Symposium: Antiviral Therapy Using Natural ProductsPreclinical In Vitro Activity of QR-435 Against Influenza A Virus as a Virucide and in Paper Masks for Prevention of Viral TransmissionOxford, John S PhD1; Lambkin, Robert PhD1; Guralnik, Mario PhD2*; Rosenbloom, Richard A MD, PhD3; Petteruti, Michael P BS3; DiGian, Kelly PhD2; LeFante, Carolyn RN2Author Information 1Retroscreen Virology, London, United Kingdom; 2Synergy Research, Teaneck, NJ; and 3Quigley Pharma, Doylestown, PA. QR-435 was provided by Quigley Pharma Inc., Doylestown, PA. These studies were funded by a grant provided by Quigley Pharma Inc. *Address for correspondence: 266 Johnson Avenue, Teaneck, NJ 07666. E-mail: [email protected] American Journal of Therapeutics: September 2007 - Volume 14 - Issue 5 - p 455-461 doi: 10.1097/MJT.0b013e3180a6f9c2 Buy Metrics Abstract Prophylaxis against influenza is difficult, and current approaches against pandemics may be ineffective because of shortages of the two proven classes of antivirals in the face of a large-scale infection. Herbal/natural products may represent an effective alternative to conventional attempts to protect against infection by avian influenza virus. QR-435, an all-natural compound of green tea extract and other agents, has been developed to provide protection against a wide range of viral infections. The antiviral activities of several QR-435 preparations as well as QR-435 (1) green tea extract were tested against A/Sydney/5/97 and A/Panama-Resvir 17 strains of avian influenza virus H3N2 by means of an assay based on Madin-Darby canine kidney cells. Toxic effects of QR-435 formulations on these cells were also evaluated as were the virucidal properties of a commercially available mask impregnated with QR-435. The efficacy of a QR-435/mask combination was compared with that of the QR control/mask combination, an untreated mask, and no mask. QR-435 had significant in vitro activity against H3N2 at concentrations that were not associated with significant cellular toxic effects. The antiviral activity of QR-435 (1) was similar to that of QR-435. Masks impregnated with QR-435 were highly effective in blocking the passage of live H3N2 virus. These preclinical results warrant further evaluation of the prophylactic use of QR-435 against viral infection in humans. © 2007 Lippincott Williams & Wilkins, Inc.