Below is an excerpt from the book Clinical Botanical Medicine:
Numerous other herbs have shown potential as antiherpes treatments. As mentioned above, Chinese rhubarb root is one of these that has been shown effective, combined with sage, for treating patients with herpes labialis. Though Chinese rhubarb contains tannins that might explain its activity, most research has focused on the anthraquinones in this plant most renowned for their cathartic laxative properties in higher doses. One study found that anthraquinones from Chinese rhubarb as well as several other herbs, including Frangula purshiana (cascara sagrada) bark, Rhamnus frangula (alder buckthorn) root, Senna alexandrina (cassia) leaf, and Aloe barbadensis latex, were virucidal to HSV and other enveloped viruses in vitro.1
Injection of an ethanolic extract of Chinese rhubarb, presumably low in tannins (as the compounds are quite toxic when present in high concentrations in the body) in mice infected with HSV, was as effective as acyclovir in one Chinese study.2 Ethanol extract of Chinese rhubarb blocked HSV attachment and penetration in vitro.3
Melia azedarach (China tree, chinaberry) root bark and fruit are traditional Chinese remedies for many infectious diseases. A limonoid compound from the leaves of this tree was shown to inhibit HSV in vitro.4 A protein from the leaves, meliacine, has been more extensively studied and shown to interfere with HSV–DNA synthesis and viral maturation and envelope formation.5 This protein inhibited formation of herpetic keratitis in a mouse study when applied topically, whereas placebo had no protective effect.6 A compound in the fruit, 28- deacetylsendanin, has been shown to block HSV replication and to reduce HSV thymidine kinase production.7 Another study concluded that chinaberry compounds not only inhibit replication but also act as immunomodulators.8 We believe whole herb extracts of this plant need to be studied to find out if synergy among the various constituents provide equally or more effective results. At least one study of an aqueous extract of a close relative, Melia toosendan, has shown that it can prevent viral attachment in vitro.
1. Sydiskis RJ, Owen DG, Lohr JL, et al. Inactivation of enveloped viruses by anthraquinones extracted from plants. Antimicrob Agents Chemother 1991;35(12):2463– 2466.
2. Wang ZY, Xu B, Song YY, et al. Inhibition effects of rhubarb ethanol extract on herpes simplex virus infection in vivo. Zhonghua Shi Yan He Lin Chuang Bing Du Xue Za Zhi. 2003 June;17(2):169– 173 [in Chinese].
3. Hsiang CY, Hsieh CL, Wu SL, et al. Inhibitory effect of anti- pyretic and anti- inflammatory herbs on herpes simplex virus replication. Am J Chin Med 2001;29:459– 467.
4. Alche LE, Ferek GA, Meo M, et al. An antiviral meliacarpin from leaves of Melia azedarach L. Z Naturforsch [C] 2003;58:215– 219.
5. Alche LE, Barquero AA, Sanjuan NA, et al. An antiviral principle present in a purified fraction from Melia azedarach L. leaf aqueous extract restrains herpes simplex virus type 1 propagation. Phytother Res 2002;16:348– 352.
6. Pifarre MP, Berra A, Coto CE, et al. Therapeutic action of meliacine, a plant-derived antiviral, on HSV-induced ocular disease in mice. Exp Eye Res 2002;75:327– 334.
7. Kim M, Kim SK, Park BN, et al. Antiviral effects of 28- deacetylsendanin on herpes simplex virus- 1 replication. Antiviral Res 1999;43:103– 112.
8. Barquero AA, Michelini FM, Alche LE. 1- cinnamoyl- 3,11- dihydoximeliacarpin is a natural bioactive compound with antiviral and nuclear factor- kappaB modulating properties. Biochem Biophys Res Comm 2006;344:955– 962.
Clinical Botanical Medicine by Eric Yarnell, N.D., R.H., Kathy Abascal, B.S.,J.D. Robert Rountree, M.D.