Introduction Soil extract materials, particularly the class of substances known collectively as “Humus,” “humics,” “humic Acid(s),” or “humates,” have been widely used in a number of applications for many years. Both natural soil extracts and synthetic humates have been employed extensively in horticultural and related industries, particularly for soil enhancement and as soil remediation agents. In addition, both natural and synthetic materials have been employed as additives for use in organic gardening and landscaping, and in fresh-water aquaria. Medicinal benefits have also been claimed for both synthetic and naturally occurring humates. For example, humic materials have long been used as “Folk remedies” for a wide variety of illnesses; their anti-inflammatory properties are also well documented. In addition, humic substances have been shown to exhibit anti-microbial as well as anti-viral efficacy, and are particularly active against coxsackie virus A9, herpes simplex virus (HSV) types 1 and 2, human immunodeficiency virus (HIV), and influenza virus types A and B. Laub BioChemicals Corporation contracted with Specialty Laboratories (SL) to investigate the antiviral activities of proprietary synthetic humic acid as well as naturalproduct humic acid on HSV-1 (ATCC Strain VR-260) and HSV-2 (ATCC Strain VR734), respectively. SL agreed to test both naturally-occurring humic acid and synthetic products at different concentrations to determine their respective IC50 and IC99. Three series of experiments were designed and performed to verify the antiviral activities natural-product humic acid:

• (1) Experiment Series I: Cell Protection against Viral Infection (a). Fresh monkey kidney cells (target cells) were incubated with virus and testing compounds for one hour, then cultured without the testing compounds.
• (2) Experiment Series II: Cell protection against viral infection (b). Target cells were first exposed to drugs, then to virus, and then were cultured without drugs.
• (3) Experiment Series III: Infected-cells recovery from viral infection. Target cells were first infected with virus first and then cultured with drugs.

Conclusions No cytotoxicities were observed in any of the compounds tested up to 500 ug/mL, suggesting that neither the synthetic humic acid compounds nor the natural-product humate material are toxic to the cells tested The anti-HSV-1 and anti-HSV-2 effects were examined. Furthermore, three series of experiments were designed to explore the potential mechanisms of action. The first series of experiment demonstrated that both compounds can inactivate both HSV-1 and HSV-2 infections with different anti-viral activities. The second series of experiments demonstrated that the compounds can protect cells against HSV-1 and HSV-2 infection. The third series of experiments demonstrated that the compounds can interfere the proliferation of HSV-1 and HSV-2 after the virus enters the cells. The primary goal of these experiments was to provide “proof of the principle.” It is concluded that synthetic as well as natural-product humates have anti-viral effects on well-characterized HSV-1 and HSV-2 testing strains. Different potencies were observed against HSV-1 and HSV-2 under different experimental conditions. Further evaluation of the anti-viral effects on drug-resistant HSV-1 or HSV-2 strains is warranted.