Elsayed A. Aboutabl

Phytochemical and pharmacological studies on Sideritis taurica Stephan ex Wild

Fatty acids (FA), hydrocarbons, alpha-amyrin, stigmasterol and beta-sitosterol were identified in the n-hexane extract of the aerial parts of Sideritis taurica Stephan ex Wild. Xanthotoxin, as well as 2-acetyl-3-hydroxy-5,6,8-trimethoxy-1,4-naphthoquinone were isolated from the methylene chloride extract of the plant. In addition to apigenin 7-O-beta-D-glucopyranoside and apigenin, previously reported from the plant, hypolaetin 7-O-beta-D-allopyranosyl-O-beta-D-glucopyranoside was isolated from the ethyl acetate extract. From the methanol extract, isoscutellarein 7-O-beta-D-allopyranosyl-O-beta-D-glucopyranoside was also isolated. Toxicity study of petroleum ether extract (f(1)), ethanolic extract (f(2)), dichloromethane fraction of f(2) (f(3)) and n-butanolic fraction of f(2) (f(4)) of the plant proved that it is relatively nontoxic. The tested extracts and fractions exhibited significant analgesic, anti-inflammatory, anti-ulcerogenic and antihyperglycaemic activities, but no anticonvulsant and antipyretic effects, as compared with control groups and reference drugs.

Secondary metabolites and bioactivities of Myrtus communis

Background: Myrtus species are characterized by the presence of phenolic acids, flavonoids, tannins, volatile oils and fatty acids. They are remedies for variety of ailments. This study therefore investigated medicinal effects of Myrtus communis L. Methods: Bioactivity studies of Myrtus communis L. leaves were carried out on volatile oil, 7% methanol and aqueous extracts and the isolated compounds myricetin 3-O-β-glucopyranoside, myricetin 3-O-∝–rhamnopyranoside and gallic acid. Results: Determination of the median lethal dose (LD50) revealed that the volatile oil, alcoholic and aqueous extracts were practically nontoxic and highly safe as no lethality was observed. The tested materials (volatile oil, alcoholic and aqueous extracts, myricetin 3-O-β-glucopyranoside, myricetin 3-O-∝–rhamnopyranoside and gallic acid) showed significant antihyperglycemic, anti-inflammatory and antinociceptive effects as compared with control groups and reference drugs. Conclusion: Administration of extracts of M. communis leaves could be safe at the dose used in this study.

A possible general mechanism for ultrasound-assisted extraction (UAE) suggested from the results of UAE of chlorogenic acid from Cynara scolymus L. (artichoke) leaves

The use of ultrasound-assisted extraction (UAE) for the extraction of chlorogenic acid (CA) from Cynara scolymus L., (artichoke) leaves using 80% methanol at room temperature over 15 min gave a significant increase in yield (up to a 50%) compared with maceration at room temperature and close to that obtained by boiling over the same time period. A note of caution is introduced when comparing UAE with Soxhlet extraction because, in the latter case, the liquid entering the Soxhlet extractor is more concentrated in methanol (nearly 100%) that the solvent in the reservoir (80% methanol) due to fractionation during distillation. The mechanism of UAE is discussed in terms of the effects of cavitation on the swelling index, solvent diffusion and the removal of a stagnant layer of solvent surrounding the plant material.

3-Keto-22-epi-28-nor-cathasterone, a brassinosteroid-related metabolite from Cystoseira myrica

Bioassay-guided purification of an ethanolic extract of Cystoseira myrica against HEPG-2 (liver) and HCT116 (colon) human cancer cell lines led to the isolation of 3-keto-22-epi-28-nor-cathasterone, 1 and cholest-4-ene-3,6-dione, 2. This finding allowed us to report for the first time that a brassinosteroid-related metabolite occurs in seaweed. These compounds showed activity in the range of 12.38-1.16 microM with selective activity of compound 2 to liver cancer cell lines.

Antioxidant activity of methanolic extract of Bombax ceiba.

Abstract The antioxidant activity of a methanolic extract of Bombax ceiba was evaluated using several antioxidant assays, in terms of its: (i) ability to scavenge DPPH (1,1-diphenyl-2-picryl-hydrazyl) and hydroxyl free radicals; (ii) action against lipid peroxidation (in rat liver microsomes and soy bean phosphatidylcholine liposomes), induced by ascorbyl radicals and peroxynitrite; and (iii) effect on myeloperoxidase activity. The cytotoxicity was monitored through the mitochondrial activity in the Vero cell line. The extract showed antioxidant activity in all assays, the EC50 (μg/ml) for DPPH was 87 and for lipid peroxidation of microsomes and soy bean liposomes induced by ascorbyl radicals were 141 and 105, respectively, and by peroxynitrite were 115 and 77, respectively. The K0.5 value for myeloperoxidase activity inhibition by the extract was 264 μg/ml. The extract showed very low toxicity toward Vero cells.

Water soluble polysaccharides extracted from Pterocladia capillacea and Dictyopteris membranacea and their biological activities

Cold and hot water extracts (CWE, HWE) of both the red alga Pterocladia capillacea (P. capillacea) and the brown alga Dictyopteris membranacea (D. membranacea) were studied for their polysaccharide contents. In both (CWE) and (HWE) extracts. Relatively higher yields were obtained in case of P. capillacea pillacea (2.87 and 6.46%, respectively). The polysaccharide contents of the CWE hydrolyzate of both studied algae analyzed by HPLC were found to be enriched with glucuronic acid, arabinose and glucose, whereas, HWE hydrolyzate were found to be rich in glucuronic acid and fructose. The polysaccharide contents of the CWE and HWE extracts of (D. membranacea) showed appreciable antimicrobial activity in addition to a moderate antitumor activity against HELA (Cervix carcinoma cell line) at IC50 = 9.83 μg/dl, respectively. Whereas the polysaccharide contents of the CWE and HWE extracts of (P. capillacea) exhibited a promising anticoagulant activity.

Flavonoid glycosides and pharmacological activity of Amphilophium paniculatum

Background: Nothing is reported on Amphilophium paniculatum (L.) Kunth. This study aimed at investigation of chemical constituents of the leaves of Amphilophium paniculatum, grown in Egypt, in addition to pharmacological evaluation. Materials and Methods: Isolation of a new compound, along with 5 known flavonoids. Pharmacological activities were carried out on different extracts of A. paniculatum leaves. Results: Identification of a new flavone glycoside, acacetin 8-C-β-D- glucopyranosy l-(1→2)-α-L-rhamnopyranoside (1) in addition to 5 known flavonoids. The 70% ethanol crud extract and its successive chloroform, ethyl acetate, and 100% ethanol extracts showed significant anti-inflammatoryactivity,analgesic effect, antipyretic activity, antioxidant activity, and anti-hyperglycemic activity. Determination of the median lethal dose (LD50) revealed that the different extracts were safe.

Bioactive terpenoids from the Red Sea soft coral Sinularia polydactyla

Chemical investigation of an ethyl acetate soluble fraction of Sinularia polydactyla (Ehrenberg) led to the isolation of three known terpenoides, two of them sterols, 24-methylcholestane-3β,5α,6β,25-tetrol 25-monoacetate (1), 24-methylcholestane-5-en-3β,25-diol (2), in addition to a cembranoid diterpene, durumolide C (3), for the first time. The cytotoxicity and antimicrobial activities of the ethyl acetate extract and the isolated compounds 1–3 were evaluated in vitro. Durumolide C (3) showed selective cytotoxicity against HepG2 (IC50 1.0 μg/mL), whereas 24-methylcholestane-3β,5α,6β,25-tetrol 25-monoacetate (1) showed IC50 of 6.1 and 8.2 μg/mL against Hep2 and HCT human cancer cell lines, respectively.

Phytochemical and pharmacological studies on Leonotis leonurus

The present study aimed at isolation of the flavonoid constituents of Leonotis leonurus R. Br. (Lamiaceae) flowering aerial parts, identification of the isolated compounds, and evaluation of the hepatoprotective, anti-inflammatory and cytotoxic activities of the aqueous alcoholic and chloroform extracts. Isolation of the flavonoid constituents was performed using chromatographic techniques. Ten flavonoid compounds were isolated and identified as six flavone glycosides, two methylated flavones, and two flavone aglycons. The structures were established through chemical and spectral analysis. Paracetamol-induced hepatotoxicity, carrageenan-induced hind rat paw edema and sulforhodamine B (SRB) assay were used in the evaluation of hepatoprotective, anti-inflammatory and cytotoxic activities, respectively. The 70% methanol and chloroform extracts showed strong hepatoprotective and anti-inflammatory activity; no cytotoxic activity was observed at the chosen extract concentrations and they possess promising protective activity against paracetamol-induced hepatic damage and anti-inflammatory activity in rats. The flavonoids isolated from Leonotis leonurus in this study were found to be isolated for the first time from the genus Leonotis.

Hopane-type saponins from Polycarpon succulentum growing in Egypt

Abstract Two new hopane-type saponins, succulentosides A and B, were isolated from Polycarpon succulentum (whole plant). Based on spectral analyses (including 2D NMR, and FAB-mass spectroscopy), the structures of succulentosides A and B were characterized as 6α-O-[α- L-arabinopyranosyl-(1-3)-α- l -arabinopyranosyl ]-β-O-β- d -xylopyranosyl -16β-O-β- d -xylopyranosyl-22- hydroxyhopane , and 6α-Oα- l -arabinopyranosyl -3β-O-β- d -xylopyranosyl -16β-O-β- d -xylopyranosyl-22-hydroxyhopane , respectively.