FDA Application Summary

This is high power polarized light photomicrograph showing the protocatechuic acids crystals after a spray has dried on glass

Summary of Supporting Evidence:

The following is a summary of the Emergency Use Authorization (EUA) application to the FDA. This shows what has been learned in more than 10 years basic science research on the use protocatechuic acid as an antibiotic.

As of December 2020, there was no known therapy for COVID19.  Vaccination of segments of the population in USA was initiated.  If successful, wide spread vaccination of the populous was months away.

The defense remains as mitigation; wearing of masks, hand washing and social distancing. Sanitizing hard surfaces is not as critical since the virus dies when dry.

A recent discovery of a phytochemical called protocatechuic acid was viricidal for the SARS CoV2 virus on contact.  Since PCA is a nutraceutical, it can be legally marketed without prior FDA approval. Its practical application as a sanitizer is for increasing the protective coating on face masks, personal protective equipment, and hands. It may be used for coating of filters in ventilation recirculation systems.

Alcohol sprays have limited effect.  The kill germs when wet, but not after evaporation. That is where the genius of residual coating of PCA becomes important.  PCA crystalline coating on hands, masks, ventilation filters provides a long lasting antiviral effect.

Importance: The importance of this petition is that protocatechuic acid (PCA) has many clinical applications, including those for humanitarian, societal, civil defense and military health and personal well-being. The most important timely reason for this application is the pandemic and the need for interruption of the transmission and treatment of SARS CoV2 virus with immediate translation to clinical practice.

Evidence-Based Submission: Although PCA is a nutraceutical it has been subject to study as though it was a drug and securing evidence for an FDA application.

Basic Science: This submission has basic scientific evidence supporting the hypothesis that protocatechuic acid (PCA) will disrupt the transmission and treat SARS Co-2 virus; Severe Acute Respiratory Syndrome Coronavirus 2 of the genus Betacoronavirus. (see below)

The Reagent: Protocatechuic acid is a phytochemical, the primary metabolite of cyanidin-3-glucoside (C-3-G). C-3-G is an anthocyanin and a flavonoid. C-3-G is a dye that contributes to the colors found in plants, vegetables, and fruits.

Anti-Oxidant: PCA is a powerful anti-oxidant; 10 times more powerful than vitamin E. Antioxidants are fundamental to health.

Anti-Inflammatory: PCA is a powerful anti-inflammatory reagent. Inflammation is known to be the common denominator of all diseases.

Increase Expression of Growth Factors: PCA has demonstrated to have the potential to cause enhancement of local growth hormone, IGF-1, and growth factors to health and or regenerate cells and or tissue. This has been demonstrated in human and animal synovium to produce IGF-1. It has been shown in rodent taped stripped skin wounds to heal in 2 days with a collagen layer regenerated in the skin. It has been shown in dose-related amounts to cause human osteoblasts and mesenchymal stem cells to make bone.

Broad Spectrum Antibiotic: The following study established that PCA was a broad-spectrum antibiotic.

Jalali, Omid; Best, Molly; Wong, Alison; Schaeffer, Brett; Bauer, Brendon; Johnson, Lanny. Reduced Bacterial Burden of the Skin Surrounding the Shoulder Joint Following Topical Protocatechuic Acid Application Results of a Pilot Study. JBJS Open Access d 2020:e19.00078. http://dx.doi.org/10.2106/JBJS.OA.19.00078

Human Studies: The safety and effectiveness for controlling potential pathogens on human volunteer’s skin exploring PCA topical solutions as a surgical disinfectant.

The following study established that a skin penetration formulation including PCA was effective in controlling potential bacterial pathogens on the human skin, specifically C. acnes which resides below the surface in the hair follicles and sebaceous glands. There were no adverse reactions.

Jalali, Omid; Best, Molly; Wong, Alison; Schaeffer, Brett; Bauer, Brendon; Johnson, Lanny. Protocatechuic Acid as a Topical Antimicrobial for Surgical Skin Antisepsis. Preclinical Investigations. JBJS Open Access: July-September 2020 – Volume 5 – Issue 3 – p e19.00079 doi: 10.2106/JBJS.OA.19.00079

PCA is found throughout nature; in the soil and plants. It is common to the human diet. The human bowel bacteria manufacture PCA in small amounts.

Protocatechuic acid is safe. PCA is classified by the FDA as a food flavoring additive. PCA has an existing FDA G.R.A.S. designation as Generally Recognized As Safe as a flavoring substance. http://www.ift.org/~/media/Food%20Technology/pdf/2009/06/0609feat_GRAS24text.pdf

Its FEMA number is 4430 as PCA is chemically listed by its chemical designation: 3,4 dihydroxybenzoic acid.

PCA is not toxic. On 9/27/2017 toxicity testing was performed at Product Safety Labs with a dose level of 5000 mg/kilogram on rodents. It was reported in Laboratory study number 41068 that the LD50 following a single oral delivery was greater than 5000 mg/kg body weight in female rats.

The conversion to a human relative dose to exceed safety would be 350,000 milligrams per day for a 70- kilogram human. This amount not likely to be ingested at once or over a period of time. The recommended oral dose for humans would be 500-1000 milligrams per day.

The present production methods for PCA are biochemical. The products are absent of trace metals. PCA is readily available in large amounts from several international manufacturers.

PCA Biofilm Destroying Properties: PCA is a physical crystal retaining this condition in the air (dry) as well as in a liquid vehicle or environment. The physical shape is one of sharp edges and projections, even shown to be needle-like in solution. (see below) The irregular sharp projections physically disrupt a bacterial biofilm and the prongs and coating of SARS CoV2 upon contact.

This was demonstrated in the biofilm destroying studies supporting US patent 10,004,705: Antimicrobials and the methods of use. 7/26/2018. This patent was based upon an independent contract laboratory (WuXiapptec Marietta, GA) studies performed by ASTM E-2647 Drip Flow Biofilm Reactor.


Anti-viral History: PCA has been reported to be therapeutically effective against several viral diseases.


Ou C, Shi N, Yang Q, Zhang Y, Wu Z, et al. (2014) Protocatechuic Acid, a Novel Active Substance against Avian Influenza Virus H9N2 Infection. PLoS ONE 9(10): e111004. doi:10.1371/journal.pone.0111004.

Guo Y, Zhang Q, Zuo Z, et al. Protocatechuic acid (PCA) induced a better antiviral effect by immune enhancement in SPF chickens. Microb Pathog. 2018;114:233-238. doi:10.1016/j.micpath.2017.11.068

Infectious Bursal Disease Virus

Ou CB, Pan Q, Chen X, Hou N, He C. Protocatechuic acid, a new active substance against the challenge of avian infectious bursal disease virus [published correction appears in Poult Sci. 2012 Oct;91(10):2722. Pang, Q [corrected to Pan, Q]]. Poult Sci. 2012;91(7):1604-1609. doi:10.3382/ps.2011-02069

Hepatitis B

Jiyang Li1, Hai Huang1, Meiqing Feng, Wei Zhou, Xun long, ShiPei ZhouIn vitro and in vivo anti-hepatitis B virus activities of a plant extract from Geranium carolinianum L.


Avian Influenza Virus

Ou C, Shi N, Yang Q, Zhang Y, Wu Z, et al. (2014) Protocatechuic Acid, a Novel Active Substance against Avian Influenza Virus H9N2 Infection. PLoS ONE 9(10): e111004. doi:10.1371/journal.pone.0111004

Influenza A and B:

Hils J, May A, Sperber M, Klocking R, Helbig B, et al. (1986) Inhibition of several strains of influenza virus type A and B by phenolic polymers. Biomed Biochim Acta 45: 1173–1179.

Xiao-Qing Dai 1 , Wen-Tao Cai 1 , Xiao Wu, Yong Chen , Feng-Mei Han.  Protocatechuic acid inhibits hepatitis B virus replication by activating ERK1/2 pathway and down-regulating HNF4α and HNF1α in vitro.  Life Sciences     Volume 180, 1 July 2017, Pages 68-74.

Lu, F., Tseng, S., Li, M. et al. In vitro anti-influenza virus activity of synthetic humate analogues derived from protocatechuic acid. Arch. Virol. 147, 273–284 (2002). https://doi-org.proxy1.cl.msu.edu/10.1007/s705-002-8319-5


Hassan, Sherif T. S.; Švajdlenka, Emil; Berchová-Bímová, Kateřina.  Hibiscus sabdariffa L. and Its Bioactive Constituents Exhibit Antiviral Activity against HSV-2 and Anti-enzymatic Properties against Urease by an ESI-MS Based Assay. Molecules.  Vol. 22 Issue 5, p. 722, 2017.

PCA’s Mode of Action on SARS CoV2:

Crystals Physical Properties: Traditional antimicrobials function chemically or biochemically.  Their biochemical inter-action disrupts the viral interaction with the host and/or physically disrupts the virus prongs or wall.  Crystals by their physical nature have similar known cytotoxic properties.

Mulay, S., Desai, J., Kumar, S. et al. Cytotoxicity of crystals involves RIPK3-MLKL-mediated necroptosis. Nat Commun 7, 10274 (2016). https://doi.org/10.1038/ncomms10274

Mulay et al further state:

“Crystals are deposits of various sizes and shapes composed of atoms, ions or biomolecules, frequently with tissue injury, inflammation and re-modelling. Two mechanisms may explain this association:

  • nucleation or crystal growth from a seed crystal formed on a surface medium, for example tubular epithelial cells, urolithiasis forming at Randall’s plaques, calcifications in injured tendons, damaged cartilage or atheromatous vascular lesions,
  • crystal formation itself causes tissue injury and inflammation, for example in gouty arthritis, pulmonary silicosis or asbestosis, cholesterol crystals driving atherogenesis and in oxalate, cystine or urate nephropathy.

Crystals trigger tissue inflammation via the NLRP3 inflammasome- and caspase-1-mediated secretion of IL-1β and IL-18.

However, crystals also exert direct cytotoxic effects leading to necrotic rather than apoptotic cell death.”

This is evidence that the physical properties of crystals have an antimicrobial property, independent or in conjunction with their biochemical properties.  They have the potential to physically disrupt the microbe’s integrity.

The coronaviruses are particularly vulnerable.  The covering of the coronavirus is surrounded by many projections like a crown.  The projections called “prongs” or “spikes”.  These spikes are the virulent contact agent with the host cell.  They penetrate the human cell and the infection is propagated.

“One of the few mercies during this crisis is that, by their nature, individual coronaviruses are easily destroyed. Each virus particle consists of a small set of genes, enclosed by a sphere of fatty lipid molecules, and because lipid shells are easily torn apart by soap, 20 seconds of thorough hand-washing can take one down. Lipid shells are also vulnerable to the elements; a recent study shows that the new coronavirus, SARS-CoV-2, survives for no more than a day on cardboard, and about two to three days on steel and plastic. These viruses don’t endure in the world. They need bodies.”  https://www.theatlantic.com/science/archive/2020/03/biography-new-coronavirus/608338/

The spikes and underlying thin coating are vulnerable to physical disruption.  Physical disruption is one potential method of stopping the invasion and the clinical disease.

Crystals have a physical structure that is irregular, rough and sharp with potential to physically disrupt a microbes’ spikes and cover.

Various other crystals have this anti-microbial potential.

  • Benzalkonium Chloride.
  • 3-Trimethoxy silyl propyl dimethyloctadecyl Ammonium Chloride.
  • Salts
    • Sodium Chloride.
    • Calcium chloride.
    • Magnesium chloride.
  • Protocatechuic acid (PCA)
  • Co-Crystals of protocatechuic acid

Benzalkonium Chloride action is thought to be due to disruption of intermolecular interactions. This can cause dissociation of cellular membrane lipid bilayers, which compromises cellular permeability controls and induces leakage of cellular contents. Other biomolecular complexes within the bacterial cell can also undergo dissociation.

3-Trimethoxy silyl propyl dimethyl octadecyl Ammonium Chloride.  Zoono’s reagent creates a defensive, antimicrobial layer at a nano-scale (1 nm = 1 billionth of a meter), ZOONO® is not only claimed to be more effective than traditional disinfectants, it also has the benefit of working consistently over a protracted period of time. ZOONO ® is proven effective for up to 30 days on a hard surface & 24 hours on human skin. The ZOONO ® technology not only offers unmatched consistent antimicrobial efficacy, but because it does not kill pathogens by toxicity, the organisms cannot adapt to it, so there is no possibility of immunity developing as they can with traditional forms of disinfection. ZOONO® is also compatible with current sanitation regimens and can be used to augment current practices providing the continuous efficacy traditional sanitizers cannot offer.

The active ingredient in ZoonoÔ is 3-Trimethoxy silyl propyl dimethyl octadecyl Ammonium Chloride.  After drying it forms a crystal on the surface that are 100 times smaller than the human hair. ZoonoÔ kills microbes using lysis, the disruption of a micro-organism’s cellular membrane.


Sodium Chloride:  This common salt has been used to coat face masks.  As a result, the crystal attached to the fibers result in an antimicrobial barrier.  https://www.businessinsider.com/mask-coated-in-salt-neutralizes-viruses-like-coronavirus-2020-2

The salt is a crystal and acts by puncturing the covering of the virus.  The salt coating has worked effectively against three viruses.  See:  https://www.nature.com/articles/srep39956

Quan, F., Rubino, I., Lee, S. et al. Universal and reusable virus deactivation system for respiratory protection. Sci Rep 7, 39956 (2017). https://doi.org/10.1038/srep39956

The crystals of Calcium and Magnesium chloride salts may also be used or combined for this purpose.

In addition to physical disruption many microorganisms cannot live in a salty environment: water is drawn out of their cells by osmosis.

Protocatechuic acid (PCA):  PCA is a broad-spectrum antibacterial biofilm destroying antibiotic when coating of cloth and or metal surfaces (US patent 10,004,705).  PCA has the physical properties of a crystal with sharp protrusions that have been reported to disrupt the coating of microbes.

Ajiboye TO, Habibu RS, Saidu K, et al. Involvement of oxidative stress in protocatechuic acid-mediated bacterial lethality. Microbiologyopen. 2017;6(4):e00472. doi:10.1002/mbo3.472

The crystal structure of a reagent causes physical disruption of bacterial and viral coating resulting in microbe death.  The PCA crystal was first reported to be in three forms in 1949.

The following publication from 1949 is extensively illustrated.  The present-day significance is that PCA in a fluid environment retains its crystalline anti-viral properties.  The crystalline physical nature is constantly changing in solution.

Copied from https://royalsocietypublishing.org/doi/10.1098/rspa.1949.0064

Robert Williams Wood

Published:22 June 1949.  https://doi.org/10.1098/rspa.1949.0064

Abstract:  In this paper an extensive study is reported of the very remarkable, and thus far apparently unique, case of the deformation in three dimensions of protocatechuic acid, to which attention was drawn many years ago by Otto Lehmann. The deformations are spontaneous, and are probably due to progressive gliding of the lattice planes, which exist in two configurations, one stable and the other unstable, the latter being the condition of the long prismatic rods when they first form. Such a prism presently deforms into a zigzag crystal, with stable and unstable sections in alternation which, with continuation of the deformation, becomes again straight, but now in the stable configuration. The bending is progressive, like that of an umbrella case, pendant from the end of an oblique cane pointed down, when the latter is pushed into it. The movements are so rapid that motion pictures, made with a microscope, were necessary for the observation of certain stages of the deformation. The deformations have been shown to many chemists and physicists during the past decade or more, none of whom had ever seen or heard of this remarkable type of crystal movement. The deformations are usually observed as the warm saturated solution cools, but they also occur after the crystal has been dried for many hours.

From Wood figures showing crystalline nature of PCA in solution.

In 1983 Agmon, et al supported Wood’s work and showed that some crystalline shapes were stable in form and other were rapidly changing.

Agmon I, Herbstein FH, Thomas JM.  Spontaneous deformation of protocatechuic acid monohydrate crystals: crystallographic aspects. Proc. R. Soc. Lond. 1983. A387311–330. http://doi.org/10.1098/rspa.1983.0062

The following illustrations were taken from Agmon, et al.  1983

PCA Crystalline Coating of Surfaces: The dual method has clinical importance in that PCA in a liquid (water, alcohol or other vehicles) retains various crystalline form of varying shapes, but all with sharp edges.  This crystalline antimicrobial factor exists whether in a liquid vehicle or dried on a hard surface.  The alcohol kills when wet and then leaves a PCA crystalline coating for continued anti-microbial effect.

The PCA viricidal property would exist for the dry crystalline PCA on a surface.  The SARS CoV2 virus in the liquid droplet would engage the dry crystal, immediately changing the environment to liquid.  The PCA crystal is only slowly 1.24% soluble in water and its transition to the fluid state would be slow and the virus would have been inactivated before the PCA in any significant amount was soluble.  The SARS CoV2 virus would inactivated upon engagement with the PCA crystal.

Recent studies verified the crystalline nature of PCA in alcohol and water.  The following photomicrographs show by polarized light microscopy the PCA crystals appearance while in in water and or alcohol before drying.

Clinical Therapeutic Significance: The sharp edges of the crystals disrupt the prongs and lipid coating of the SARS CoV2 virus.  The other therapeutic characteristics of PCA take over; low pH, anti-protease, blocking of docking, anti-tyrosinase, anti-inflammation factors, and hormonal and cellular immunity enhancement.

This photomicrograph on the left in water shows the needle physical shapes of PCA in early phase of going into solution.  Note the prism shapes not yet converted to needle shapes in interval of 30 minutes.  On the right the PCA is already needle shaped in alcohol solution in the same time frame due to increased solubility in alcohol as compared to water.

The associated in vitro studies reported below replicated the clinical environment in reducing transmission.  The PCA crystal coating on a hard or cloth article was viricidal for SARS CoV2 virus. The same would be for any coating on skin or other like surfaces.

Low pH:  Drugs that change the pH at the surface of the cell membrane and inhibit the fusion of the virus to the cell membrane. It can also inhibit nucleic acid replication, glycosylation of viral proteins, virus assembly, new virus particle transport, virus release, and other processes to achieve its antiviral effects.

Fox RI. Mechanism of action of hydroxychloroquine as an antirheumatic drug.

Semin Arthritis Rheum 1993; 23:82–91.

PCA has an acid pH of 5.4 which is disruptive to viral coating.

Takeda Y1Okuyama Y2Nakano H3Yaoita Y2Machida K2Ogawa H4Imai K5.

Antiviral Activities of Hibiscus sabdariffa L. Tea Extract Against Human Influenza A Virus Rely Largely on Acidic pH but Partially on a Low-pH-Independent Mechanism.  Food Environ Virol. 2020 Mar;12(1):9-19. doi: 10.1007/s12560-019-09408-x. Epub 2019 Oct 16.

Abstract:  Influenza A virus (IAV) infection is perennially one of the leading causes of death worldwide. Effective therapy and vaccination are needed to control viral expansion. However, current anti-IAV drugs risk inducing drug-resistant virus emergence. Although intranasal administration of whole inactivated virus vaccine can induce efficient protective immunity, formalin and β-propiolactone are the currently used and harmful inactivating agents. Here, we analyzed the antiviral activity of hibiscus (Hibiscus sabdariffa L.) tea extract against human IAV and evaluated its potential as a novel anti-IAV drug and a safe inactivating agent for whole inactivated vaccine. The in vitro study revealed that the pH of hibiscus tea extract is acidic, and its rapid and potent antiviral activity relied largely on the acidic pH. Furthermore, the mouse study showed that the acidic extract was not effective for either therapeutic or vaccination purposes. However, hibiscus tea extract and protocatechuic acid, one of the major components of the extract, showed not only potent acid-dependent antiviral activity but also weak low-pH-independent activity. The low-pH-independent activity did not affect the conformation of immunodominant hemagglutinin protein. Although this low-pH-independent activity is very limited, it may be suitable for the application to medication and vaccination because this activity is not affected by the neutral blood environment and does not lose antigenicity of hemagglutinin. Further study of the low-pH-independent antiviral mechanism and attempts to enhance the antiviral activity may establish a novel anti-IAV therapy and vaccination strategy.

The pH based (3.6) has Selective Effect on Various Food Borne Virus.

Joshi SS, Dice LD’Souza DH.  Aqueous Extracts of Hibiscus sabdariffa Calyces Decrease Hepatitis A Virus and Human Norovirus Surrogate Titers.  Food Environ Virol.  2015 Dec;7(4):366-73. doi: 10.1007/s12560-015-9209-1. Epub 2015 Jul 5.

Abstract: Hibiscus sabdariffa extract is known to have antioxidant, anti-diabetic, and antimicrobial properties. However, their effects against foodborne viruses are currently unknown. The objective of this study was to determine the antiviral effects of aqueous extracts of H. sabdariffa against human norovirus surrogates (feline calicivirus (FCV-F9) and murine norovirus (MNV-1)) and hepatitis A virus (HAV) at 37 °C over 24 h. Individual viruses (~5 log PFU/ml) were incubated with 40 or 100 mg/ml of aqueous hibiscus extract (HE; pH 3.6), protocatechuic acid (PCA; 3 or 6 mg/ml, pH 3.6), ferulic acid (FA; 0.5 or 1 mg/ml; pH 4.0), malic acid (10 mM; pH 3.0), or phosphate buffered saline (pH 7.2 as control) at 37 °C over 24 h. Each treatment was replicated thrice and plaque assayed in duplicate. FCV-F9 titers were reduced to undetectable levels after 15 min with both 40 and 100 mg/ml HE. MNV-1 was reduced by 1.77 ± 0.10 and 1.88 ± 0.12 log PFU/ml after 6 h with 40 and 100 mg/ml HE, respectively, and to undetectable levels after 24 h by both concentrations. HAV was reduced to undetectable levels by both HE concentrations after 24 h. PCA at 3 mg/ml reduced FCV-F9 titers to undetectable levels after 6 h, MNV-1 by 0.53 ± 0.01 log PFU/ml after 6 h, and caused no significant change in HAV titers. FA reduced FCV-F9 to undetectable levels after 3 h and MNV-1 and HAV after 24 h. Transmission electron microscopy showed no conclusive results. The findings suggest that H. sabdariffa extracts have potential to prevent foodborne viral transmission.

Anti-Protease:  COVID-19 main protease (Mpro) is the key enzyme of coronavirus which plays crucial role in virus replication and transcription, which can be targeted to retard the growth of virus inside the host.

Bhatia S, Giri S, Lal AF, Singh S.  Battle Against Coronavirus: Repurposing Old Friends (Food Borne Polyphenols) for New Enemy (COVID-19). ChemRxiv. 2020. https://doi.org/10.26434/chemrxiv.12108546.v1


One of the major protein of COVID 19 is Mpro (main protease), also referred to as the “3C-like protease” belonging to the proteases class of hydrolytic enzymes. This enzyme plays a key role in the processing of pp1a (responsible for generating copies of viral genome) and pp1ab (responsible for generating viral genome) as involved in their proteolytic cleavage at the conserved residues among COVID 19 genome.

These can assemble to give rise to virions inside the host cell and thus, replicate to produce multiple copies as shown in Figure 2. Mpro can act as potential target for structure based drug discovery as this enzyme not only involved in autocatalytic cleavage of itself and key viral enzymes, as well as lacks any close homologues among human host. Targeting this enzyme using suitable protease small molecule inhibitor holds immense potential to curb virus replication and transcription which are critical steps in virus life cycle.

Chandani SR, Lokhande KB, Swamy KV, Nanda RK, Chitlange SS. Data on docking of phytoconstituents of Actinidia deliciosa on dengue viral targets. Data Brief. 2019;25:103996. Published 2019 May 17. doi:10.1016/j.dib.2019.103996

Anti-docking:  Molecular docking is an important tool in computer-based drug design and drug discovery which helps to predict the small ligand conformation and orientation (Docking pose) within the active sites of the target receptor protein.

Protocatechuic acid has high docking score (-9.8) and importantly protocatechuic acid derivatives shows comparatively better pharmacokinetic predictions and lead likeness, along with the ease of synthesis.   PCA is bioavailable by oral intake as in black tea the focus of this report.

PCA as one of the polyphenolic scaffolds have affinity to bind with substrate-binding pocket of COVID-19 virus Mpro ,which is highly conserved among all CoV Mpros. This investigation intensely supports our hypothesis that small molecule inhibitors (PCA) targeting Mpro or in combination with other adjuvant therapies could provide an effective therapeutic regime to fight against all coronavirus associated diseases.

The top six docked polyphenols which were mainly derivatives of protocatechuic acid polyphenols.

Their pharmacokinetics study pointed out the poor bioavailability of these polyphenols if taken 22 individually as active compound. However, protocatechuic acid (1 Lipinski violation) derivative among all have shown better pharmacokinetic profile.

The focus of this study suggested that the dietary intake of black tea” can improve the resistance to fight against COVID 19 virus in early stages of human infection. Importantly though, the enriched subset of six compounds identified from the larger library has to be validated experimentally.  PCA is one of the ingredients needing further study.

Ganesh SM, Awasthi P, Timiri AK, Ghosh M.  A novel approach for rationale selection of medicinal plants against viruses via molecular docking studies.  December 2014.  In

Oak Jubilee Volume 2015; pages 18-30.  ISSN 0379-556X (Print)/ ISSN 2347-6001 (Online) The Pharmstudent.  https://old.iitbhu.ac.in/phe/pharmsociety/issue_2015/3.GaneshM_et_al.pdf

In Ganesh we learn that flavonoids are found to be good antiviral agents and have excellent docking scores and inhibition constant values.  PCA is a flavonoid and found in Euphorbia hirta which is rich in flavonoids; i.e. protocatechuic acid.  PCA has anti-protease inhibition.

The following publication showed PCA docking potential in HIV-1 virus.

Pattarapan Panthong, Kingkan Bunluepuech, Nawong Boonnak, Prapaporn Chaniad, Somsak Pianwanit, Chatchai Wattanapiromsakul & Supinya Tewtrakul (2015) Anti-HIV-1 integrase activity and molecular docking of compounds from Albizia procera bark, Pharmaceutical Biology, 53:12, 1861-1866, DOI: 10.3109/13880209.2015.1014568

Enhanced Hormonal and cellular immunity: The results of Ou, et al indicate that PCA may improve the poultry health by enhancing both the humoral and cellular immune response.

Guo Y, Zhang Q, Zuo Z, et al. Protocatechuic acid (PCA) induced a better antiviral effect by immune enhancement in SPF chickens. Microb Pathog. 2018;114:233-238. doi:10.1016/j.micpath.2017.11.068

This evidence is particularly important in that recent reports have shown COVID19 has changed form a biological disease to one of attacking the patient’s immunity.

Anti-inflammatory properties as a catabolic cytokine blocker:  One of the ways the human body responds to SARS CoV-2 is with a massive anti-inflammatory response.  This has been termed a “cytokine storm” in the lungs.  It results in further inflow of fluids to the already compromised lungs.

PCA has powerful anti-inflammatory properties with clinical relevance for the “cytokine storm” associated with clinical SARS CoV2 infections.  It also reduced the C-reactive protein (Lin, et al)

Lin CY, Huang CS, Huang CY, Yin MC. Anticoagulatory, antiinflammatory, and antioxidative effects of protocatechuic acid in diabetic mice. J Agric Food Chem. 2009;57(15):6661-6667. doi:10.1021/jf9015202

Lende AB, Kshirsagar AD, Deshpande AD, et al. Anti-inflammatory and analgesic activity of protocatechuic acid in rats and mice.  Inflammopharmacol.12 July 2011.  DOI 10.1007/s10787-011-0086-4


PCA has powerful anti-inflammatory by its anti-catabolic cytokine blocker properties.

Anti-tyrosinase Inhibitor: PCA acts as a tyrosinase inhibitor in other applications and has potential in viral treatment.

Miyazawa M, Oshima T, Koshio K, Itsuzaki Y, Anzai J. Tyrosinase Inhibitor from Black Rice Bran.  J. Agric. Food Chem. 2003, 51, 24, 6953-6956.  October 28, 2003.


Van Tieghem N, Doyen A, Liteanu D, Cogniaux J, Frühling J. Modulation of tyrosinase activity and viral information by 5-iodo-deoxyuridine and L-dopa in a human melanoma cell line [proceedings]. Arch Int Physiol Biochim. 1979;87(4):857-858.

Anti-thrombosis Properties:  PCA, similar in structure to aspirin will slightly increase the prothrombin time.  This is especially beneficial for prophylactic or therapeutic treatment in covid19 clinical cases that may have thrombosis.

Lin CY, Huang CS, Huang CY, Yin MC. Anticoagulatory, anti-inflammatory, and antioxidative effects of protocatechuic acid in diabetic mice. J Agric Food Chem. 2009;57(15):6661-6667. doi:10.1021/jf9015202.

Huang L, Lin C, Li A, Wei B, Teng J, Li L. Pro-coagulant activity of phenolic acids isolated from Blumea riparia. Nat Prod Commun. 2010;5(8):1263-1266.

Independent Contract Laboratory Testing:  The experimental model was such that it primarily replicated the clinical liquid environment in which the SARS CoV-2 comes in contact with the crystals of PCA.  This method replicated the transmission and the environment for treatment.

A dry environment was created at 60 minutes in the first phase of one of the labs testing, so both liquid and drying of the crystal coating was tested.

Illinois Technical Institute

July 17, 2020

Dr. Lanny L. Johnson, M.D.
314 East Crystal Downs Drive
Frankfort, MI 49635

Re:         Study 2969001001001: Testing Protocatechuic Acid (PCA) as a Possible Treatment Against SARS-CoV-2 Infected cells in vitro

Dear Dr. Johnson,

The study investigation (Study # 2969001001001) of the effectiveness of Protocatechuic Acid (PCA) against SARS-CoV-2, the causative virus for COVID19 has been completed.  Testing of the PCA was initiated on June 16, 2020.

Test Article and Test Substrate identification and preparation.

The Test Article (TA) used for this study was Protocatechuic Acid (PCA) and was provided by the Sponsor.  The TA was received as an off-white powder.  The PCA solution was prepared to be 30% PCA w/v in Ethanol.  The PCA was prepared in 5g increments to pre-warmed 50-60 mL ethanol until dissolved for a total of 30g PCA in the solution.  Additional ethanol was then added volumetrically to be equivalent to 100mL.

The Test Substrates (TS) were a Plastic-type material sourced from a clear plastic laboratory bottle (Corning 431731 Octagonal bottle, 150mL), cloth (the top layer of a N95 mask [3M 8210]), and a Sponsor-provided wire mesh to serve as a substrate for the TA. All test substrates were cut to approximately 1”x 1” in size.  The test substrates were submerged into the PCA solution and dried horizontally to allow for even coating.  After the substrate was thoroughly dried, the test substrate was re-submerged into the PCA solution for an additional coating.

Test Virus and Cell Culture.

The Test Virus used for this study was 2019 Novel Coronavirus, Isolate USA-WA1/2020 (SARS-CoV-2). The virus was stored at approximately ≤ -65°C prior to use. The multiplicity of infection (MOI) was 0.01 TCID50/cell.

The Cell Culture used for the TCID50 test was African Green Monkey Kidney Cells (Vero E6 cells) that were maintained in Dulbecco’s Minimum Essential Medium with 10% fetal calf serum (DMEM-2).  All growth media contained heat-inactivated fetal calf serum and antibiotics.

Study Design:

The test design is shown below in Table 1.  This test will assess the TA on a substrate in various conditions as shown in Table 1.

  1. The Test Substrates were coated with PCA as described above. The test substrates were treated with PCA twice and allowed to fully dry overnight.  In general, the time from the first coat to the next day’s virus exposure was approximately 24 hours and the second coat was applied approximately 203 hours later.  Total time between the final PCA coat to the initiation of the study was approximately 21-22 hours. The coated test substrates were stored in a Safety Hood that was continuously operating until the initiation of the study.
  2. The PCA-treated Test Substrate was placed into a sterile 6 well cell culture plate and approximately 100 µL total of a ≥1 x 106 TCID50/mL SARS-CoV-2 virus was such that 50 µL of virus was layered on each sides of the treated test substrates. This was the procedure used for the initial Day 1 experiment.

For the Day 2 test, in an attempt to increase the recorded titer of the controls, the treated test substrate plus TA was placed into a sterile 6 well cell culture plate and the same amount of virus was layered onto both sides of the test substrate.  However, an addition 50 µL of DMEM was added to each side to reduce the inactivation of the virus due to desiccation.  Additionally, a glass coverslip was also added to help mitigate against evaporation.  The Day 2 test also served as a confirmatory for the Day 1 test.

Note: In comparison between the Day 1 test to the Day 2 test procedures, the Day 1 test, examined the inactivation of the virus in an environment with less humidity/moisture than the Day 2 confirmatory test which was modified to have 100 µL (50 µL per side) extra DMEM and a cover slip to mitigate against evaporation.

  1. After application of the virus, the virus was contact with the test substrates for approximately 10 minutes (Groups 1, 2, and 3, Control groups 7, 8, and 9), 60 minutes (Groups 4, 5, and 6, Control Groups 10, 11, and 12). Each substrate per time per test article was performed in duplicate.

A cell culture-only control was included to indicate that cells without any TA or virus remain healthy throughout the assay.  Virus-only controls without substrate was added for each time point to verify that the assay was performing as expected.

  1. After the incubation time, the treated substrates and control substrates were washed with 1 mL of cell culture media (DMEM-2) for approximately 5-10 minutes within the 6-well cell culture plate and the glass cover slip removed if necessary. This was the equivalent to a 10-fold dilution.  The plate was gently stirred via an orbital shaker to enhance the recovery of the virus.
  2. For the TCID50, the cell culture media (DMEM-2) used to wash the test substrate was serially diluted 10 fold and transferred into respective wells of a 96-well plate which contained a monolayer of African Green Monkey Kidney Cells (Vero E6 cells) for titration. The TCID50 assay was performed non-GLP according to IITRI Standard Operating Procedures for the assay.  The TCID50 titers were calculated using the method of Reed-Meunch.

Table 1: Study Design

GroupTest and Control GroupsPCA
1Plastic (10 minute exposure)2 replicates
2Cloth (10 minute exposure)2 replicates
3Mesh (10 minute exposure)2 replicates
4Plastic (60 minute exposure)2 replicates
5Cloth (60 minute exposure)2 replicates
6Mesh (60 minute exposure)2 replicates
7Virus Control- Plastic (10 minute exposure)2 replicates
8Virus Control- Cloth (10 minute exposure)2 replicates
9Virus Control- Mesh (10 minute exposure)2 replicates
10Virus Control- Plastic (60 minute exposure)2 replicates
11Virus Control-Cloth (60 minute exposure)2 replicates
12Virus Control-Mesh (60 minute exposure)2 replicates


The test article, test substrates and virus (SARS-CoV-2) were prepared according to protocol and each preparation was noted in the study notebook for this study.

Two experimental days were run for this study with the second day as run as a confirmatory.  For Day 1, after coating the test substrates with PCA as described above (Groups shown in Table 1 above), a TCID50 was performed at 10 minutes or 60 minutes after initial application of the virus.  There was an observed log difference between the experimental groups (Group 1: Plastic-10 min, Group 2: Cloth-10 min, Group 3: Mesh-10 min, Group 7: Plastic-60 min, Group 8: Cloth-60 min, Group 9: Mesh-60 min ) when compared to the controls (Group 4: Plastic-10 min, Group 5: Cloth-10 min, Group 6: Mesh-10 min, Group 10:Plastic-60 min, Group 11: Cloth-60 min, Group 12: Mesh-60 min).

Observed Day 1 results did indicate some log reductions in infectious virus titers under the experimental conditions performed for this study when compared to controls.  The results are shown below in Table 2.

Table 2: Initial Experimental Run Results

GroupTest Article/substrateReplicateIncubation timeTCID50 Log10/mL*Log averageSt.Dev.log difference^
1PCA/plastic110 Min3.753.750.00-0.63
PCA/plastic210 min3.75
2PCA/Cloth110 min2.752.750.00-1.25
PCA/Cloth210 min2.75
3PCA/Mesh110 min3.503.380.18-0.25
PCA/Mesh210 min3.25
4Control/plastic110 Min3.754.380.88N/A
Control/plastic210 min5.00
5Control/Cloth110 min3.754.000.35N/A
Control/Cloth210 min4.25
6Control/Mesh110 min3.753.630.18N/A
Control/Mesh210 min3.50
7PCA/plastic160 Min3.252.880.53-1.13
PCA/plastic260 Min2.50
8PCA/Cloth160 Min2.502.750.35-1.00
PCA/Cloth260 Min3.00
9PCA/Mesh160 Min1.001.500.71-2.00
PCA/Mesh260 Min2.00
10Control/plastic160 Min3.754.000.35N/A
Control/plastic260 Min4.25
11Control/Cloth160 Min4.003.750.35N/A
Control/Cloth260 Min3.50
12Control/Mesh160 Min3.253.500.35N/A
Control/Mesh260 Min3.75
13Virus control (no coupon)N/A10 min5.75N/AN/AN/A
14Virus control (no coupon)N/A60 min5.75N/AN/AN/A

*limit of detection is 1.5 TCID50 Log10/mL

^Log difference is defined as the averaged TCID50 Log10/mL from virus control on substrates – TCID50 Log10/mL from replicate test group.  Log difference indicates amount of reduction in infectious virus when comparing the virus control on substrate to the test group.

For Day 2, after coating the test substrates with PCA as described above (Groups shown in Table 1 above), a TCID50 was performed at 10 minutes or 60 minutes after initial application of the virus.  There was a modification to the procedures to see if the viral titers could be increased.  The Day 2 test as an attempt to mitigate against the drying effect observed in the Day 1 test had modifications that included adding an additional 50 µl of DMEM on each side of the test substrate and a glass coverslip placed on top of the test substrate, thereby creating a more aqueous environment than the Day 1 run. As with the Day 1 run, there was an observed log difference between the experimental groups (Group1: Plastic-10 min, Group 2: Cloth-10 min, Group 3: Mesh-10 min, Group 7:Plastic-60 min, Group 8: Cloth-60 min, Group 9: Mesh-60 min ) when compared to the controls (Group 4:Plastic-10 min, Group 5: Cloth-10 min, Group 6: Mesh-10 min, Group 10:Plastic-60 min, Group 11: Cloth-60 min, Group 12: Mesh-60 min ) as shown in Table 3, thereby confirming the log differences observed from the Day 1 run.

Table 3: Confirmatory Experimental Run Results

GroupTest Article/substrateReplicateIncubation timeTCID50 Log10/mL*Log averageSt.Dev.log difference^
1PCA/plastic110 Min4.254.380.18-1.13
PCA/plastic210 min4.50
2PCA/Cloth110 min4.254.250.00-1.13
PCA/Cloth210 min4.25
3PCA/Mesh110 min4.754.630.18-1.13
PCA/Mesh210 min4.50
4Control/plastic110 Min5.505.500.00N/A
Control/plastic210 min5.50
5Control/Cloth110 min5.505.380.18N/A
Control/Cloth210 min5.25
6Control/Mesh110 min5.755.750.00N/A
Control/Mesh210 min5.75
7PCA/plastic160 Min3.503.630.18-1.50
PCA/plastic260 Min3.75
8PCA/Cloth160 Min2.002.751.06-2.38
PCA/Cloth260 Min3.50
9PCA/Mesh160 Min4.504.380.18-0.88
PCA/Mesh260 Min4.25
10Control/plastic160 Min5.005.130.18N/A
Control/plastic260 Min5.25
11Control/Cloth160 Min4.505.130.88N/A
Control/Cloth260 Min5.75
12Control/Mesh160 Min5.255.250.00N/A
Control/Mesh260 Min5.25
13Virus control (no coupon)N/A10 min5.75N/AN/AN/A
14Virus control (no coupon)N/A60 min5.75N/AN/AN/A

*limit of detection is 1.5 TCID50 Log10/mL

^Log difference is defined as the averaged TCID50 Log10/mL from virus control on substrates – TCID50 Log10/mL from replicate test group.  Log difference indicates amount of reduction in infectious virus when comparing the virus control on substrate to the test group.

Table 4, below, compares the Day 1 results with the Confirmatory.

Table 4: Comparison Between Day 1 and Day 2 Runs

Test Article/substrateIncubation timeDay 1: Log differenceDay 2: Log difference
PCA/plastic10 Min-0.63-1.13
PCA/Cloth10 min-1.25-1.13
PCA/Mesh10 min-0.25-1.13
PCA/plastic60 Min-1.13-1.50
PCA/Cloth60 min-1.00-2.38
PCA/Mesh60 min-2.00-0.88


A PCA coating on the three test substrates, appeared to show some effectiveness in reducing infectious virus titers in the experimental condition shown in the protocol after the 10 minutes and 60 minutes post-exposure incubation when compared to the virus control on substrate. From both the Day 1 and the Day 2 runs, the log reduction varied between a 0.63 to a 2.38 log reduction.

Overall, although overall effectiveness was somewhat varied between runs and test substrate, these results show that PCA. when coated approximately 24 hours prior to virus exposure, can reduce infectious virus performance on treated (PCA) substrates in both the drier and more aqueous test conditions of the Day 1 and Day 2 runs, respectively. Additionally, it appears that a longer incubation time may be slightly more effective than the shorter 10-minute time. For your reference, a 1 to 2 log reduction/difference corresponds to a 90 to 99% inactivation while a 3 log reduction corresponds to a 99.9% inactivation.

Respectfully Submitted,

Winston C. Lin, Ph.D

Sr. Research Biologist

Microbiology and Molecular Biology Division

Life Sciences Group

Robert O. Baker, Ph.D

Assistant Vice-President and Manager

Microbiology and Molecular Biology Division

Life Sciences Group


MRI Global Preliminary Result Report:

“Sorry I didn’t get this to you last week, I was out of office. You will still be getting a formal report but for now I just wanted to send you a preliminary summary of your results. Please keep in mind the numbers may change slightly after another round of QC but for the most part will remain the same.”

Assay: Test coupons made of stainless steel, plastic and K95 mask were coated in 30% w/v PCA in 70% ethanol. Each coupon was dipped in PCA, allowed to dry, dipped again and allowed to dry with the opposite side of the coupon facing up. Once dry, 200 ul virus was added to each coupon and allowed to dry (45 minutes – 1h drying time). Virus was recovered by adding 2 ml DMEM/F12 media and washing the coupon, without scraping so as not to dislodge PCA crystals. A yellow color change in the media was observed indicating acidification of the media upon addition to the PA-coated coupon. The recovered virus was added to empty 96 well plates and diluted 1:10 down the plate. This was then added to Vero E6 cells that had grown to ~70% confluence. Cytotoxicity controls without virus and recovery controls without PCA were also done in the same manner. After addition to the cells, plates were read at day 4 for the presence of cytopathic effect (CPE) due to viral infection of cells. Note that cytotoxicity and CPE cannot be differentiated in this assay, thus any dead cells are marked as positive.

Results: Cytotoxicity was seen up to 1:100 dilution for the K95, and 1:10 for the stainless steel and plastic coupons. Positive CPE for virus recovery controls was seen at least down to 1:10,000 dilutions for all 3 coupon materials, thus each coupon material was adequate for coupon testing. Results are shown in the table below. The SS = stainless steel, K95 = K95 nask and P = plastic. +PCA means coupons coated with PCA (in pink). No PCA (e.g. SS-1) indicates virus recovery controls with no PCA coating that had virus dried and recovered (in blue).

Sample NameReplicate #TCID50TCID50/mLLog10 TCID50Average TCID50Average Log10 TCID50Log Reduction to Virus ControlsPercent Log Reduction

Kristy Solocinski, PhD

Staff Scientist

Medical Countermeasures

425 Volker Boulevard

Kansas City, MO 64110


2nd Study at MRIGlobal

A second study was performed starting upon drying of the sprayed PCA crystals and waiting 2 hours for determining the results.

Sample NameReplicate #TCID50Log10 TCID50Average TCID50Average Log10 TCID50Log Reduction to Virus ControlsPercent Log Reduction


The earliest time of effectiveness was immediate and up to 24 hours after the sprayed crystals had dried on the articles.

The second factor was that the PCA crystal were effective at 10 and 60 minutes as well as 2 hours after the coating had dried.

Most importantly was the evidence to support labeling of PCA as viricidal reagent based upon the up to 99.99% or 4-log reduction on the plastic article in liquid environment.

Transmission Disruption:  The transmission of this respiratory virus is primarily by person to person droplet spread by speech, cough, sneeze, shouting and singing.  The air born droplets of larger size may fall by gravity, while smaller size may be suspended in air for an extended period of time.

The other means of transmission source is the virus on hard surfaces or another person’s skin; i.e. shaking hands.  The duration is short on hard surfaces as the aqueous drop dries.  However, in the time period before dehydration the virus remains infective.  While active the virus may be engaged by the persons hands.  There is a need for coating of human hands.

The experimental model replicated the clinical transmission of the virus in a fluid medium.  In one application this replicated the virus containing liquid droplet of a host’s speech, cough or sneeze whereby the virus would engage the crystal coatings of PCA.  This replicated a preventive coating of Personal Protective Equipment (PPE) to interrupt the transmission to another person, especially a health care worker.

The experimental model replicated the clinical presence of the crystals on human skin, oral or nasal opening, or nasopharynx for the purpose of transmission interruption.  The crystals applied to these anatomical reagents take residence in the liquid medium inherent in these anatomical regions.

The experimental model replicated the delivery of the PCA crystals in solution by fogging, spraying, misting methods to deliver a residual coating of PCA crystals to subjects, hard surfaces, rooms, arenas, etc.  This interrupts the transmission by the PCA engaging the virus on the subject and or hard surface and those residual droplets known to be suspended in air of a period of time.

The experimental model in one phase replicated the coating of a hard object or mask material with PCA, allowed to dry and demonstrated the subsequent contact of the virus droplet resulted in SARS CoV2 inactivation.

This photograph illustrates three different concentrations of PCA crystals on polyester shirt material. The localized area was sprayed with the respective solutions. The 30% was used to easily visualize the deposited crystal coating. The crystals are present at 1% and 5%, but less visible to the naked eye. This illustration replicates what would exist on personal protective equipment (PPE).

Treatment: The experimental model replicated the fluid environment found perfused throughout the human body; saliva, blood, respiratory tract.  Therefore, a SARS CoV2 therapeutic route would include topical application, ingestion, but also intravenous and or intraperitoneal.

It has been reported that PCA inhibited virus replication in vitro:  Hils J, May A, Sperber M, Klocking R, Helbig B, et al. (1986) Inhibition of several strains of influenza virus type A and B by phenolic polymers. Biomed Biochim Acta 45: 1173–1179.

Since PCA retains crystalline properties in fluid there is continued potential for physical disruption of the virus in vivo in nasopharynx, bronchi, lungs, and blood plasma.

PCA is a strong anti-inflammatory reagent and would have therapeutic application in the clinical “cytokine storm” that occurs with SARS Co-2 infection.

PCA has anti-coagulant properties similar to aspirin and therefore would be of therapeutic value in prevention or treatment of the occasional thrombosis that occurs with SARS Co-2 infection.

There is the further therapeutic opportunity for nebulizer and or ventilator system filters and or delivery.

Translational Medicine:  Recognizing the safety of PCA its rapid clinical translation should be realized.  In its FDA designation as food supplement its commercialization is possible without FDA prior approval in some applications, providing all the necessary disclaimers.  This can be for oral route and or topical skin sanitizer.

There would be immediate application to nursing homes, meat and the chicken producers.  There would be immediate application to facility air filter; hospitals, operating rooms, and nursing homes.

Clinical trials would safely be initiated for prophylaxis.

Clinical trials may include any and all other modalities including disinfectants, PPE, oral route and in respirators and ventilators.

EPA:  I have application in place for bacteria and biofilms.  There are some of the above that will be EPA jurisdiction for coating of hard surfaces in disruption of SARS CoV2 transmission.

From: PRIARegistrationTracking@epa.gov <PRIARegistrationTracking@epa.gov>
Sent: Monday, April 13, 2020 4:26 PM
To: Matthew Brooks <mwbrooks@ag-chem.com>
Cc: Djapao.Banza@epa.gov <Djapao.Banza@epa.gov>; oppcommunications@epa.gov <oppcommunications@epa.gov>

Email:  mwbrooks@ag-chem.com


Your application dated 03/23/2020 for a New Registration, PCA SprayAway, 95946-R has been received by EPA’s Office of Pesticide Programs.

Receipt number assigned:       1049878

EPA receipt date:              03/26/2020

If this submission is not subject to PRIA, this will be your last automated notification related to this submission.


FDA:  The mask coating may be regulated as a device.  The skin coating may be regulated as a drug.  Further therapeutic testing will likely require clinical studies.