M.A. Al-Yahya’s research while affiliated with King Saud University and other places

The present study was conducted to determine whether an ethanolic extract of Citrus medica ‘Otroj’ (EEOT) can possibly exert nephroprotective and antioxidant activity against gentamicin-induced renal toxicity in rats. Wistar albino rats of either sex were divided into four groups. Group-1 received normal saline. Group-2 received gentamicin (GM) (80 mg/kg/d, for 8 days intraperitoneally). Group-3 and 4 received EEOT (250 and 500 mg/kg/d, for 21 days orally) plus gentamicin simultaneously. The rats were sacrificed on the twenty first day and kidneys were collected for histopathological assessment. Renal activities were determined in serum for gamma glutamyl transferase (GGT), creatinine, urea and uric acid. Moreover, non-protein sulfhydryl (NP-SH) malondialdehyde (MDA) and total protein (TP) were determined in renal tissues. Additionally, in vitro protection against 2′,7′-dichlorofluorescein-induced human nephrotoxicity was carried out with HEK293 cells using MTT assay. GM caused an elevation in serum GGT, creatinine, urea and uric acid, a reduction of the NP-SH and TP levels and an increase the MDA concentration in the kidney tissue. Administration of EEOT significantly protected kidney tissues against nephrotoxic effect of gentamicin as evident from amelioration of the marker enzymes and lipid peroxidation and elevated NP-SH and TP levels, besides some indices of histopathological alterations. The MTT-test showed a 48% protection at a concentration of 1 mg/ml. It is concluded that C. medica could protect the kidney against oxidative stress induced by gentamicin probably through its antioxidant and/or free radical scavenging properties caused by flavonoids and limonene.

The effect of oral administration of 0.25 g/kg/day of Citrullus colocynthis fruits, 0.25 g/kg/day of Rhazya stricta leaves or mixture of the two plants at 0.25 g/kg/day of C. colocynthis fruits plus 0.25 g/kg/day of R. stricta leaves in Najdi sheep was examined. Oral administration of 0.25 g/kg/day of C. colocynthis fruits or 0.25 g/kg/day of R. stricta leaves for 42 days proved not fatal but that of the mixture of the two plants (0.25 g + 0.25 g/kg/day) proved fatal within 26 days with profuse diarrhea, dehydration, loss in condition, ataxia and recumbency, prior to death. These manifestations accompanied by enterohepatonephrotoxicity, gelatinization of the renal and epicardial fat and transudate in serous cavities were correlated with alterations in serum LDH and AST activities and concentrations of total protein, albumin, globulin, bilirubin, cholesterol and urea and hematology.

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The fruits of Cucumis prophetarum Jusl. ap. L (N. O. Cucurbitaceae) has afforded a new diseco -sterol characterized as 5 (10), 13 (14)- diseco -stigma-5 (6), 9 (11)-diene-3-a-ol (1) on the basis of chemical and spectral analysis, and has been designated as cucumidisecosterol, along with earlier reported triterpenoids, namely, cucurbitacin-A and B.

Abstract An ethanol extract of Cyamopsis tetragonoloba (Guar) has been studied for its ability to inhibit gastric secretion and to protect gastric mucosa against the injury caused by pylorus ligation, hypothermic restraint stress, indomethacin, and various necrotizing agents including 80% ethanol, 0.2 M NaOH and 25% NaCl in rats. An oral dose of 500 mg/kg of the extract produced inhibition of normal gastric secretion in rats. The extract inhibited acetylcholine-induced contractions of isolated guinea pig ileum, suggesting anti-cholinergic activity. The intensity of gastric lesions induced by hypothermic restraint stress and indomethacin was reduced significantly by Guar extract. It produced a marked cytoprotective effect against all the necrotizing agents used in this study. The extract not only increased the gastric wall mucus significantly but also restored the ethanol-induced depletion of nonprotein sulfhydryl (NP-SH) content in the glandular stomachs of rats.

Abstract Chenopodium botrys L. growing in Saudi Arabia is rich in essential oil (2% v/w). The GC/MS and spectroscopic data of the gross terpenoid constituents are presented. α and β-eudesmol were the major sesquiterpenes in the oil. The antimicrobial activity of the oil is also recorded.

Abstract An ethanol extract of Aframomum melegueta (AMZ) has been studied for its ability to inhibit gastric secretion and to protect gastroduodenal mucosa against the injuries caused by pyloric ligation, hypothermic restraint stress, indomethacin, cysteamine and cytodestructing agents (80% ethanol, 0.6 M HCl, 0.2 M NaOH and 25% NaCl) in rats. The results of this study demonstrate that ethanol extract of AMZ had significant effects on various experimentally-induced ulcers. It produced a dose-dependent inhibition of basal gastric secretion in pylorus-ligated rats and reduced significantly the intensity of gastric lesions induced by pylorus ligation, hypothermic restraint stress, indomethacin, mucosal damaging agents and duodenal ulcers induced by cysteamine. The concentration of nonprotein-sulfhydryls was decreased significantly in gastric mucosa after administration of 80% ethanol. Treatment with AMZ extract replenished the reduced level of gastric mucosal nonprotein sulfhydryls. Acute toxicity tests showed no toxic symptoms and mortality over a period of 14 days with doses of 0.25–4g/kg. These findings suggest that AMZ extract exerts antiulcer effects by its antisecretory activity, increasing gastric mucosal resistance and cytoprotective activities.

Abstract Ethanol and/or the chloroform from chloroform: water partitioned ethanol extracts of 106 higher plant species growing in Saudi Arabia were examined in a series of in vitro and in vivo antitumor bioassays. Bioactivity in the form of 9KB or 9PS cytotoxicity, brine shrimp toxicity, toxicity to mice during 3PS testing, inhibition of crown gall tumors on potatoes, and for in vivo 3 PS antileukemic effects was detected in over 25 species which now are candidates for future bioactivity-directed fractionations. The results are presented in tabular form alphabetically by plant families.

Abstract The composition of the steam distilled oils of the fresh aerial parts of Pulicaria arabica (L.) Cass, and P. undulata (L.) Kostel was investigated by coupled GC-MS. Based on comparing the resultant mass spectra with available standards as well as with those delivered by the electronic data system attached to the apparatus and with reported data, many volatile components of the two species could be identified and compared. The oil of P. arabica is characterized by the presence of high percentage of sesquiterpene hydrocarbons and alcohols while that of P. undulata is rich in phenolic compounds and monoterpene hydrocarbons and comparatively low in sesquiterpene hydrocarbons.

Abstract The ethanolic extract of Euphorbia peplis L. has been screened for anti-inflammatory, analgesic and antipyretic activities in suitable experimental models. It produces significant inhibition of carrageenan-induced paw oedema and cotton pellet-induced granuloma pouch in rats and a significant reduction of yeast-induced hyperpyrexia in mice. It failed to produce any analgesic activity on the hot plate reaction time test. On hematological parameters contradictory observations were recorded as it showed a proaggregatory effect on platelets and reduced fibrinogen level without affecting prothrombin time. Among the phytoconstituents detected in this plant, flavonoids may be responsible for the observed anti-inflammatory effect of the ethanolic extract.