Kadanguslactones A-E, further oxygenated terpenoids from Kadsura angustifolia fermented by a symbiotic endophytic fungus, Penicillium ochrochloron SWUKD4.1850

The fermentation of Kadsura angustifolia with an endophytic fungus, Penicillium ochrochloron SWUKD4.1850 yielded five additional undescribed oxygenated terpenoids, kadanguslactones A-E, together with ten known compounds. Their structures were established by the extensive 1D, 2D-NMR, HR-ESI-MS, CD and X-ray crystallography data analysis. Kadanguslactone A is the first example of 1,30-cyclo-3,4; 9,10-disecocycloartanes that combine a five-membered lactone ring A with a cyclopentane ring B consisting of C-1, C-4, C-5, C-10, C-30. Kadanguslactone B was a rare highly oxygenated 18-norschiartane-type bisnortriterpenoid with spirocyclis rings F and G, whereas kadanguslactone C was an uncommon henrischinin-type schitriterpenoid containing a unique 3-one-2-oxabicyclo [3,2,1]-octane motif. The cytotoxicity against HepG2 cell line of all compounds were evaluated. Except nigranoic acid, all other metabolites have been first found in unfermented K. angustifolia, suggesting that main functional ingredients from K. angustifolia may be converted by P. ochrochloron SWUKD4.1850 into highly oxygenated terpenoids. This study provided a fascinating prospective for setting up alternative processing techniques to enhance the functionality and utility of Chinese herbal medicine.