Abstract: Phytochemical investigation of Sanrafaelia ruffonammari Verd and Ophrypetalum odoratum Diels that belongs to the rare genera confined to East African coastal forests led to the isolation of enantiomeric styrylpyrone dimer,(±)-5-methoxy-7-phenyl-[4-methoxy-2-pyronyl]-1-(E)-styryl-2-oxabicyclo-[4.2.0]-octa-4-en-3-one(1) alongside(+)-6-styryl-7, 8-epoxy-4-methoxypyran-2-one(2) and the enantiomeric(+)-(3) and(-)-6-styryl-7, 8-dihydroxy-4-methoxypyran-2-ones(4). Their structures were established by means of spectroscopic methods. In this paper we reveal for the first time the occurrence of styrylpyrones in East African biodiversity.(+)-6-Styryl-7, 8-epoxy-4-methoxypyran-2-one(2) and the dihydroxystyrylpyrone enantiomer(3) showed in vitro antifungal activity against Candida albicans at a concentration of 24.4 and 26.2 lM with zones of inhibition of 17 and 9 mm, respectively. Compound 2 exhibited strong activity in the brine shrimp test with LC₅₀=1.7 μg/mL. Their high cytotoxic and antifungal activities render them candidates for further scientific attention for drug development programs against cancer and microbial infections.

Key words: Sanrafaelia ruffonammari Verd, Ophrypetalum odoratum Diels, Styrylpyrones, Antifungal

摘要： Phytochemical investigation of Sanrafaelia ruffonammari Verd and Ophrypetalum odoratum Diels that belongs to the rare genera confined to East African coastal forests led to the isolation of enantiomeric styrylpyrone dimer,(±)-5-methoxy-7-phenyl-[4-methoxy-2-pyronyl]-1-(E)-styryl-2-oxabicyclo-[4.2.0]-octa-4-en-3-one(1) alongside(+)-6-styryl-7, 8-epoxy-4-methoxypyran-2-one(2) and the enantiomeric(+)-(3) and(-)-6-styryl-7, 8-dihydroxy-4-methoxypyran-2-ones(4). Their structures were established by means of spectroscopic methods. In this paper we reveal for the first time the occurrence of styrylpyrones in East African biodiversity.(+)-6-Styryl-7, 8-epoxy-4-methoxypyran-2-one(2) and the dihydroxystyrylpyrone enantiomer(3) showed in vitro antifungal activity against Candida albicans at a concentration of 24.4 and 26.2 lM with zones of inhibition of 17 and 9 mm, respectively. Compound 2 exhibited strong activity in the brine shrimp test with LC₅₀=1.7 μg/mL. Their high cytotoxic and antifungal activities render them candidates for further scientific attention for drug development programs against cancer and microbial infections.

关键词: Sanrafaelia ruffonammari Verd, Ophrypetalum odoratum Diels, Styrylpyrones, Antifungal