Litsea species, used in TCM, shows promise as an antiviral

Researchers from the U.S., Hong Kong, and Vietnam evaluated the anti-HIV and cytotoxic activities of compounds isolated from several Litsea plant species. The results of their study were published in The American Journal of Chinese Medicine.

• Litsea verticillata is a plant used in traditional Chinese medicine to treat swelling caused by injury or by snakebites.
• L. verticillata is the first plant with anti-HIV activities that the researchers identified for their National Institutes of Health (NIH)-funded International Cooperative Biodiversity Group (ICBG) project.
• From L. verticillata, they discovered eight novel compounds, prototypic sesquiterpenes, all of which exhibit anti-HIV activities.
• In subsequent studies, they identified 26 additional compounds from the plant with different structural types. They also discovered two new litseanes, litseaverticillols L and M, and a new sesquiterpene butenolide, litseasesquibutenolide.
• They reported that litseaverticillols L and M inhibit HIV-1 replication, with an IC50 value of 49.6 micromolar (uM).
• To further explore the antiviral properties of L. verticillata, the researchers evaluated several relatively abundant isolates, including a litseane compound, two eudesmane sesquiterpenes, and three lignans against an additional 21 viral targets.
• They found that lignans 8 and 9 are active against Epstein-Barr Virus (EBV), with EC50 values of 22.0uM (SI=3.8) and 16.2uM (SI>6.2), respectively.
• Since many antiviral compounds have already been discovered in L. verticillata, the researchers prepared 38 plant extracts from different parts of nine other Litsea species and evaluated their anti-HIV and cytotoxic activities.
• They reported that four extracts from three different Litsea species showed 97–100 percent inhibitory effects against HIV replication without showing cytotoxicity to a panel of human cell lines at a concentration of 20 micrograms per milliliter (ug/mL).

Based on their findings, the researchers concluded that the Litsea species are good plant sources of antiviral compounds that can be used against serious infections, such as HIV.

Journal Reference:

Guan Y, Wang D, Tan GT, Hung NV, Cuong NM, Pezzuto JM, Fong HH, Soejarto DD, Zhang H. LITSEA SPECIES AS POTENTIAL ANTIVIRAL PLANT SOURCES. The American Journal of Chinese Medicine. 2016;44(02):275–290. DOI: 10.1142/s0192415x16500166