Sahar El-Mekkawy

ANTI-HIV-1 AND ANTI-HIV-1-PROTEASE SUBSTANCES FROM GANODERMA LUCIDUM

A new highly oxygenated triterpene named ganoderic acid alpha has been isolated from a methanol extract of the fruiting bodies of Ganoderma lucidum together with twelve known compounds. The structures of the isolated compounds were determined by spectroscopic means including 2D-NMR. Ganoderiol F and ganodermanontriol were found to be active as anti-HIV-1 agents with an inhibitory concentration of 7.8 micrograms ml-1 for both, and ganoderic acid B, ganoderiol B, ganoderic acid C1, 3 beta-5 alpha-dihydroxy-6 beta-methoxyergosta-7,22-diene, ganoderic acid alpha, ganoderic acid H and ganoderiol A were moderately active inhibitors against HIV-1 PR with a 50% inhibitory concentration of 0.17-0.23 mM.

Anti-HIV-1 phorbol esters from the seeds of Croton tiglium

Five phorbol diesters, together with three known ones, were isolated from a MeOH extract of the seeds of Croton tiglium, and their structures were determined by spectroscopic methods and selective hydrolysis of acyl groups. These compounds were assessed for their abilities to inhibit an HIV-induced cytopathic effect (CPE) on MT-4 cells and to activate protein kinase C (PKC) associated with tumor-promoting action. 12-O-Acetylphorbol-13-decanoate and 12-O-decanoylphorbol-13-(2-methylbutyrate) effectively inhibited the cytopathic effect of HIV-1 [complete inhibitory concentration (IC100) values of 7.6 ng/ml and 7.81 microg/ml, and minimum cytotoxic concentration (CC0) value of 62.5 and 31.3 microg/ml, respectively]; however, 12-O-acetylphorbol-13-decanoate showed no activation of PKC at concentrations of 10 and 100 ng/ml. 12-O-Tetradecanoylphorbol-13-acetate (TPA) was found to be not only the most potent inhibitor of HIV-1-induced CPE (IC100 value of 0.48 ng/ml), but also the most potent activator of PKC (100% activation at 10 ng/ml).

Acylated pregnane glycosides from Caralluma tuberculata and their antiparasitic activity.

Five pregnane glycosides were isolated from Caralluma tuberculata (1-5), in addition to a known one (russelioside E, 6). The structures of the isolated compounds were elucidated by the analysis of NMR data and FAB-MS experiments. All the isolated compounds were tested for their antimalarial and antitrypanosomal activities as well as their cytotoxicity against human diploid embryonic cell line (MRC5).

Three new α-glucosidase inhibitors from guggul, the oleogum resin of Commiphora wightii

Three new compounds; epi-mukulin, (Z)-Δ 1,2 dehydroguggulsterone and Δ 6,7dehydro-20-hydroxygugglsterone were isolated from the n-hexane-soluble fraction (HSF) of the methanol extract of guggul, the oleogum resin of Commiphora wightii together with six known compounds: diasesartemin, (+)-epi-magnolin, (+)-diayangambin, gugglsterol I, (E)-guggulsterone and (Z)-guggulsterone. Their structures were elucidated on the basis of different spectroscopic data. α-Glucosidase inhibitory effects of HSF and the isolated compounds were evaluated calorimetrically. The HSF showed significant α-glucosidase inhibitory effect [IC50 value of 140 µg mL−1 (p < 0.05)]. Under the assay conditions, diasesartemin (IC50 = 60.6 ± 0.01 µM) was found to be more potent than the positive control, acarbose (IC50 = 92.94 ± 0.01 µM); a known α-glucosidase inhibitor (p < 0.05). The IC50 values of epi-mukulin and (Z)-guggulsterone were found to be 159.33 and 132.14 µM, respectively. Other compounds showed weak α-glucosidase inhibitory effects, <30% inhibition of the enzyme activity at 0.1 mg mL−1.

New sulphide derivative from Ferula rutabensis

Reinvestigation of CH2Cl2 extract of roots and rhizomes of Ferula rutabensis led to the isolation of a new trisulphide (1) and phthalic acid derivative (2). Their characterisation was based on their spectral data, including MS, 1D- and 2D-NMR.