Neurite outgrowth-inducing Drimane-type Sesquiterpenoids Isolated from Cultures of the Polypore Abundisporus violaceus MUCL 56355

Abundisporin (1), together with seven previously undescribed drimane sesquiterpenes named abundisporins A–G (2–8), were isolated from a polypore Abundisporus violaceus (Polyporaceae), collected in Kenya. Chemical structures of the isolated compounds were elucidated based on exhaustive 1D and 2D NMR spectroscopic measurements and supported by HRESIMS data. The absolute configurations of isolated compounds were determined by using Mosher’s method for 1-4 and TDDFT-ECD calculations for 4, and 5-8. None of the isolated compounds exhibited significant activities in either antimicrobial or cytotoxicity assays. All the tested compounds demonstrated neurotrophic effects with 1 and 6 significantly increasing neurite outgrowth when treated with 5 ng/mL NGF.