0000000000721813
AUTHOR
Alain Bertrand Dongmo
Antifungal steroid saponins from Dioscorea cayenensis.
From the rhizomes of Dioscorea cayenensis Lam.-Holl (Dioscoreaceae), the new 26- O- beta- D-glucopyranosyl-22-methoxy-3 beta,26-dihydroxy-25( R)-furost-5-en-3- O- alpha- L-rhamnopyranosyl-(1-->4)- alpha- L-rhamnopyranosyl-(1-->4)-[ alpha- L-rhamnopyranosyl-(1-->2)]- beta- D-glucopyranoside ( 1) was isolated together with the known dioscin ( 2) and diosgenin 3- O- alpha- L-rhamnopyranosyl-(1-->4)- alpha- L-rhamnopyranosyl-(1-->4)-[ alpha- L-rhamnopyranosyl-(1-->2)]- beta- D-glucopyranoside ( 3). Their structures were established on the basis of spectral data. Compound 2 exhibited antifungal activity against the human pathogenic yeasts Candida albicans, C. glabrata and C. tropicalis (MICs of …
A new ecdysteroid and other constituents from two Dioscorea species
Phytochemical investigation of the rhizome of Dioscorea dumetorum has led to the isolation by several chromatographic steps on normal and reversed phase silica gel of a new ecdysteroid, (20R)-5β,11α,20-trihydroxyecdysone (1), and two known ecdysteroids, ajugasterone C (2) and herkesterone (3). Their structures were determined by spectroscopic methods including 1D- and 2D-NMR (COSY, TOCSY, HSQC and HMBC). This is the first report on the occurrence of phytoecdysteroids in the Dioscoreaceae family. These compounds were devoid of antifungal activity against three Candida species (Candida albicans, Candida glabrata and Candida tropicalis, MIC > 200 μg/ml).
Antinociceptive and anti-inflammatory activities of Acacia pennata wild (Mimosaceae)
The butanolic fraction of dried leaves of Acacia pennata (Mimosaceae) was tested for analgesic and anti-inflammatory activities in animal models. It showed significant protective effects against chemical stimuli (acetic acid and formalin) in the mouse. It also produced a significant increase of the threshold of sensitivity to pressure-induced pain in the rats. The extract revealed an inhibitory effect in carrageenin-induced rat paw oedema in the late phase. The results suggested that a peripheral mechanism is involved in the analgesic, associated to anti-inflammatory effect (NSAIDs-like). Among the class of compounds characterized in this fraction, flavonoids may be mainly responsible for t…
A New Steroidal Saponin from Dioscorea cayenensis
The new 26-O-beta-D-glucopyranosyl-3beta,26-dihydroxy-20,22-seco-25(R)-furost-5-en-20,22-dione-3-O-alpha-L-rhamnopyranosyl-(1-->4)-alpha-L-rhamnopyranosyl-(1-->4)-[alpha-L-rhamnopyranosyl-(1-->2)]-beta-D-glucopyranoside (1), along with the known methyl protodioscin (2), asperoside (3) and prosapogenin A of dioscin (4) were isolated from the rhizomes of Dioscorea cayenensis LAM.-HOLL (Dioscoreaceae). Their structures were established mainly on the basis of 600 MHz 2D-NMR spectral data. 4 exhibited antifungal activity against the human pathogenic yeasts Candida albicans, C. glabrata and C. tropicalis (MICs of 20.8, 6.25, 25 microg/ml, respectively), whereas saponins 1-3 were inactive.