Identification of light-independent inhibition of human immunodeficiency virus-1 infection through bioguided fractionation of Hypericum perforatum
1 Department of Microbiology, University of Iowa, Iowa City, IA 52242, USA
2 Department of Chemistry, University of Iowa, Iowa City, IA 52242, USA
3 Department of Microbiology, Immunology and Preventive Medicine, Iowa State University, Ames, IA 50011, USA
4 Department of Food Science and Human Nutrition, Iowa State University, Ames, IA 50011, USA
5 Department of Horticulture, Iowa State University, Ames, IA 50011, USA
6 Department of Chemistry°, Iowa State University, Ames, IA 50011, USA
7 Department of Biochemistry, Biophysics and Molecular Biology, Iowa State University, Ames, IA 50011, USA
8 US Department of Agriculture-Agricultural Research Service, North Central Regional Plant Introduction Station, Ames, IA 50011, USA
Virology Journal 2009, 6:101 doi:10.1186/1743-422X-6-101Published: 13 July 2009
Light-dependent activities against enveloped viruses in St. John's Wort (Hypericum perforatum) extracts have been extensively studied. In contrast, light-independent antiviral activity from this species has not been investigated.
Here, we identify the light-independent inhibition of human immunodeficiency virus-1 (HIV-1) by highly purified fractions of chloroform extracts of H. perforatum. Both cytotoxicity and antiviral activity were evident in initial chloroform extracts, but bioassay-guided fractionation produced fractions that inhibited HIV-1 with little to no cytotoxicity. Separation of these two biological activities has not been reported for constituents responsible for the light-dependent antiviral activities. Antiviral activity was associated with more polar subfractions. GC/MS analysis of the two most active subfractions identified 3-hydroxy lauric acid as predominant in one fraction and 3-hydroxy myristic acid as predominant in the other. Synthetic 3-hydroxy lauric acid inhibited HIV infectivity without cytotoxicity, suggesting that this modified fatty acid is likely responsible for observed antiviral activity present in that fraction. As production of 3-hydroxy fatty acids by plants remains controversial, H. perforatum seedlings were grown sterilely and evaluated for presence of 3-hydroxy fatty acids by GC/MS. Small quantities of some 3-hydroxy fatty acids were detected in sterile plants, whereas different 3-hydroxy fatty acids were detected in our chloroform extracts or field-grown material.
Through bioguided fractionation, we have identified that 3-hydroxy lauric acid found in field grown Hypericum perforatum has anti-HIV activity. This novel anti-HIV activity can be potentially developed into inexpensive therapies, expanding the current arsenal of anti-retroviral agents.