title: Antifungal Enantiomeric Styrylpyrones from Sanrafaelia ruffonammari and Ophrypetalum odoratum.
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 µM 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.
authors.affiliation: Department of Traditional Medicine Research, National Institute for Medical Research, P.O. Box 9653, Dar es Salaam, Tanzania.
authors.forename: Hamisi M
authors.initials: HM
authors.lastname: Malebo
authors.affiliation: Department of Environmental Science and Management, Ardhi University, P.O. Box 35176, Dar es Salaam, Tanzania.
authors.forename: Charles
authors.initials: C
authors.lastname: Kihampa
authors.affiliation: Department of Chemistry, University of Dar es Salaam, P.O. Box 35061, Dar es Salaam, Tanzania.
authors.forename: Clarence A
authors.initials: CA
authors.lastname: Mgina
authors.affiliation: Department of Chemistry, University of Dar es Salaam, P.O. Box 35061, Dar es Salaam, Tanzania.
authors.forename: Fortunatus
authors.initials: F
authors.lastname: Sung'hwa
authors.affiliation: Department of Pharmaceutical Chemistry, Institute of Pharmacy, University of Erlangen, Schuhstrasse 19, 91052 Erlangen, Germany.
authors.forename: Reiner
authors.initials: R
authors.lastname: Waibel
authors.affiliation: Department of Chemistry, University of Dar es Salaam, P.O. Box 35061, Dar es Salaam, Tanzania.
authors.forename: Stephan A
authors.initials: SA
authors.lastname: Jonker
authors.affiliation: Department of Chemistry, University of Dar es Salaam, P.O. Box 35061, Dar es Salaam, Tanzania.
authors.forename: Mayunga H H
authors.initials: MH
authors.lastname: Nkunya
keywords: Antifungal; Ophrypetalum odoratum Diels; Sanrafaelia ruffonammari Verd; Styrylpyrones