Bouchra Meddah

Nigella sativa inhibits intestinal glucose absorption and improves glucose tolerance in rats.

AIM OF THE STUDY Nigella sativa L. (Ranunculaceae) seeds have been used traditionally for centuries, notably for treating diabetes. MATERIALS AND METHODS We studied the effects of the crude aqueous extract of Nigella sativa seeds on intestinal glucose absorption in vitro using a short-circuit current technique and in vivo using an oral glucose tolerance test. RESULTS The aqueous extract of Nigella sativa (0.1 pg/ml to 100 ng/ml) exerted dose-dependent inhibition of sodium-dependent glucose transport across isolated rat jejunum. Maximal inhibition exceeded 80% and IC50 was close to 10 pg/ml. An oral glucose tolerance test was carried out in rats after the initial dose and after a 6-week treatment of Nigella sativa (2 g/(kg day)), and compared to metformin (300 mg/(kg day)). Chronic Nigella sativa treatment improved glucose tolerance as efficiently as metformin. Nigella sativa and metformin also reduced body weight without any toxic effect. CONCLUSIONS To our knowledge, this is the first demonstration that Nigella sativa directly inhibits the electrogenic intestinal absorption of glucose in vitro. Together with the observed improvement of glucose tolerance and body weight in rats after chronic oral administration in vivo, these effects further validate the traditional use of Nigella sativa seeds against diabetes.

Bioactive metabolites from Chaetomium aureum: Structure elucidation and inhibition of the Hsp90 machine chaperoning activity

Chemical investigation of the EtOAc extract of the fungus Chaetomium aureum, an endophyte of the Moroccan medicinal plant Thymelaea lythroides, afforded one new resorcinol derivative named chaetorcinol, together with five known metabolites. The structures of the isolated compounds were determined on the basis of one- and two-dimensional NMR spectroscopy and high-resolution mass spectrometry as well as by comparison with the literature. All compounds were tested for their activity towards the Hsp90 chaperoning machine in vitro using the progesterone receptor (PR) and rabbit reticulocyte lysate (RRL). Among the isolated compounds, only sclerotiorin efficiently inhibited the Hsp90 machine chaperoning activity. However, sclerotiorin showed no cytotoxic effect on breast cancer Hs578T, MDA-MB-231 and prostate cancer LNCaP cell lines. Interestingly, deacetylation of sclerotiorin increased its cytotoxicity toward the tested cell lines over a period of 48 h.

[Atractylis gummifera: from poisoning to the analytic methods].

Atractylis L gummifera is a plant that causes every year serious and often deadly poisonings. In Morocco, 153 cases of poisoning have been recorded between January 1980 and June 1995 by the Moroccan Antipoison Centre. The ignorance by the clinicians, the fast evolution and the frequency of these poisonings are the origin of diagnosis problems. The solution of those problems is to detect atractyloside and carboxyatractyloside in the biologic liquids. Since several decades, some toxicological analytical methods were established in view of an assay. The aim of our paper is to describe the poisoning by this plant and to review the methods of toxicological analysis used from the colorimetric technique until the news recent chromatographic methods.

In Vitro and In Vivo Antioxidant and Anti-Hyperglycemic Activities of Moroccan Oat Cultivars

Improvement of oat lines via introgression is an important process for food biochemical functionality. This work aims to evaluate the protective effect of phenolic compounds from hybrid Oat line (F11-5) and its parent (Amlal) on hyperglycemia-induced oxidative stress and to establish the possible mechanisms of antidiabetic activity by digestive enzyme inhibition. Eight phenolic acids were quantified in our samples including ferulic, p-hydroxybenzoic, caffeic, salicylic, syringic, sinapic, p-coumaric and chlorogenic acids. The Oat extract (2000 mg/kg) ameliorated the glucose tolerance, decreased Fasting Blood Glucose (FBG) and oxidative stress markers, including Superoxide dismutase (SOD), Catalase (CAT), Glutathione peroxidase (GPx), Glutathione (GSH) and Malondialdehyde (MDA) in rat liver and kidney. Furthermore, Metformin and Oat intake prevented anxiety, hypercholesterolemia and atherosclerosis in diabetic rats. In vivo anti-hyperglycemic effect of Oat extracts has been confirmed by their inhibitory activities on α-amylase (723.91 μg/mL and 1027.14 μg/mL) and α-glucosidase (1548.12 μg/mL & 1803.52 μg/mL) enzymes by mean of a mixed inhibition.

In vitro Antibacterial Potential Activity of the Methanolic and Aqueous Extracts of Corrigiola telephiifolia Pourr. and Mesembryanthemum nodiflorum

Abstract The present study was conducted to investigate antibacterial activity of methanolic and aqueous extracts obtained from aerial parts of Mesembryanthemum nodiflorum and Corrigiola telephiifolia Pourr., root, using the disc-diffusion and microdilution assays. The extracts were tested against Gram-positive bacteria: Bacillus subtilis, Staphylococcus aureus, Micrococcus luteus and Gram-negative bacteria: Escherichia coli, Pseudomonas aeruginosa and Klebsiella pneumoniae. The methanol extracts of plants screened revealed promising antibacterial activities against most pathogens bacteria. Maximum activity of corrigiola telephiifolia Pourr., and Mesembryanthemum nodiflorum methanol extracts were observed against Pseudomonas aeriginosa, Klebsiella pneumoniae, Escherichia coli and Micrococcus luteus with minimal inhibitory concentration (MIC) values ranging from 3.12 to 6.25 mg/ml. The antibacterial activity of aqueous extract was less than this of methanolic extract (MIC 3.12 and 12.5 mg/ml) were observed against all tested bacteria. These species might provide promising therapeutic agents against infections with multi-resistant and pathogens bacteria.