NIGRANOIC ACID, A TRITERPENOID FROM SCHISANDRA-SPHAERANDRA THAT INHIBITS HIV-1 REVERSE-TRANSCRIPTASE

An A ring-secocycloartene triterpenoid, nigranoic acid (3,4-secocycloa rta-4(28),24-(Z)-diene-3, 26-dioic acid, (1) was isolated from the ste ms of Schisandra sphaerandra, a Chinese traditional medicinal plant. I ts structure elucidation and unambiguous NMR spectral assignment were achieved by the combination of 1D- and 2D-NMR techniques with the aid of computer modeling. Nigranoic acid showed activity in several. anti- HIV reverse transcriptase and polymerase assays.