D. W. Bishay

14-decarboxyquinovic and quinovic acid glycosides from Zygophyllum album

Further investigation of the leaves and stems of Zygophyllum album afforded four triterpene glycosides which were characterized as 14-decarboxyquinovic acid-3 beta-O-beta-D-quinovopyranosyl (1-->4)-quinovopyranoside, quinovic acid 28-O-beta-D-glucopyranosyl (2-->1)beta-D-glucopyranosyl ester, quinovic acid 27-O-beta-D-glucopyranosyl(2-->1)beta-D-glucopyranosyl ester and quinovic acid-3-beta-O-glucopyranosyl(2-->1)rhamnopyranoside. In addition, two flavonoid glycosides were isolated. The structures of the isolated compounds were established by GC, GC-MS, mass spectra, 1H and 13C NMR.

Further saponins from Taverniera aegyptiaca.

From the saponin fraction of the total methanolic extract of the dried root and stem barks of Taverniera aegyptiaca Boiss, six new triterpenoidal saponins of oleanane type were isolated and identified as 28-methyl serratagenate-3-beta-O-beta-xylopyranosyl (1-->2)-beta-glucopyranoside (2), 28-methyl serratagenate 3-beta-O-alpha-rhamnopyranosyl (1-->2)-beta-glucopyranoside (3), 3beta-O-alpha-rhamnopyranosyl (1-->2) beta-glucopyranosyl-olean-11,13(18)-dien-1beta, 3beta, 22beta-triol (4), 3beta-O-beta-glucopyranosyl (1-->2)-beta-glucuronopyranosylolean-11,13(18)-dien-1beta,3beta,22beta-triol (5), 3beta-O-beta-xylopyranosyl(1-->2)-beta-glucuronopyranosylolean-11,13(18)-dien-1beta,3beta,22beta-triol (6), 3beta-O-alpha-rhamnopyranosyl (1-->2)-beta-glucuronopyranosylolean-11,13(18)-dien-1beta, 3beta, 22beta-triol (7) together with the known oleanolic acid 3-beta-O-beta-glucoside (1). The identification of the isolated compounds was done on the basis of chemical and spectral evidences.

Antileishmanial metabolites from Geosmithia langdonii.

Antileishmanial bioassay guided fractionation of Geosmithia langdonii has resulted in the isolation and identification of two new compounds (1 and 2) together with 10 known compounds (3–12). The structures of the isolated metabolites were elucidated based on comprehensive 1D and 2D NMR spectroscopic data as well as mass spectrometry. The absolute configuration at C4, C5, and C6 of 2 was determined as R using a modified Mosher esterification method and NOESY correlations. The extracts and the isolated metabolites were evaluated for their antileishmanial activities. Compounds 3, 9, 11, and 12 were found to be active against Leishmania donovani with IC50 values of 6.9, 3.3, 8.5, and 9.2 μM, respectively, while compounds 1, 5, and 10 showed lower activities against L. donovani with IC50 values of 13.0, 47.3, and 34.0 μM, respectively.

Rapid Detection of Eight Volatile Alkaloids from Caryota mitis Lour. by LC-MS/MS and Antimicrobial Effects of their Extracts

Caryota mitis Lour. palm belongs to Family: Arecaceae. Pyridine and piperidine alkaloids are the most bioactive secondary metabolites reported in this Family. The dried leaves of Caryota mitis Lour. were subjected to defatting using n-hexane. The alkaloids were extracted from the defatted powder (marc) by acid base method. Eight pyridine/ piperidine alkaloids were detected by LC-MS and reported for the first time in the genus Caryota. The alkaloid fraction as well as other plant extract fractions showed antibacterial and antifungal activities (MIC) against selected strains.

Secondary Metabolites from the Fungus Quambalaria cyanescens

A phytochemical study of the fungus Quambalaria cyanescens led to the isolation of one new natural compound (1), along with four known compounds (2–5). The structures of the isolated metabolites were elucidated based on spectroscopic and spectrometric techniques. The fatty acid composition of Q. cyanescens was determined by GC/MS and found to consist of stearic, myristic, lauric, linoleic, cis-vaccenic, oleic, and pentadecanoic acids. All the isolated compounds were evaluated for their antimicrobial, antimalarial, and antileishmanial activities.