Isolation and characterization of a novel dihydrostilbene from Indigofera capitata kotschy with antivenin activity against Naja nigricollis venom

Medicinal plants remain one of the largest sources of novel bioactive compounds. In this study, a new dihydrostilbene (3, 3′, 5′-trimethoxy-4, 5-methylenedioxy dihydrostilbene), was isolated from the hexane fraction of the aerial parts of Indigofera capitata Kotschy (Fabaceae). Assessment of antivenin activity of the compound against Naja nigricollis venom in mice was performed. The separation and purification of the hexane-soluble portion of the methanol extract, using silica gel column chromatographic techniques, followed by crystallization afford a pure compound. Structure elucidation of the isolated compound was done using 1D and 2D nuclear magnetic resonance techniques. The isolated compound was identified to be dihydrostilbene (3, 3′, 5′-trimethoxy-4, 5-methylenedioxy dihydrostilbene), and potent in vivo antivenom effect with 50% and 16.5% survival rate at the doses of 1 mg/kg and 5 mg/kg respectively was exhibited. This compound could act as a lead for the development of a more potent therapeutic antivenin agent. To the best of our knowledge and literature search, this is the first report of the isolation and characterization as well as antivenin screening of this compound.