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.

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.

Flavonoids, anti-inflammatory activity and cytotoxicity of Macfadyena unguis-cati L.

Ethyl acetate and ethanol extracts of unflowering aerial part of Macfadyena unguis-cati L. (Fam. Bignoniaceae) were found to be rich in phenolic compounds. From ethyl acetate extract, six flavonoids were identified, 8, methoxy, acacetin, 7-O glucoside; 6, methoxy apigenin 7-O glucoside; 4'-O methyl scutellarin, 6-O apiosyl galactoside; acacetin, 7-O glucosyl, 8-C rhamnosyl, 3-O-alpha arabinofuranoside; 4'-methyl, 6- methoxy kaempferol, 7-O, 8-C diglucoside and vicenin II were isolated, while 6, methoxy, acacetin 7-O glucoside; and quercitrin were isolated from ethanol extract. These compounds were characterized and identified by their physicochemical and spectral data. The crude ethanol extract exhibited significant anti-inflammatory activity (80.47%) and moderate cytotoxic activity against lung cell line.

Polyphenols of Melaleuca quinquenervia leaves--pharmacological studies of grandinin.

Four polyphenolic acid derivatives and three ellagitannins were isolated from the leaves of Melaleuca quinquenervia (Clav.) S. T. Blake for the first time. Their structures were elucidated as gallic acid (1), ellagic acid (2), 3-O-methylellagic acid (3), 3,4,3'-tri-O-methylellagic acid (4), 2,3-O-hexahydroxydiphenoyl-(alpha/beta)-D-(4)C(1)-glucopyranose (5), castalin (6) and grandinin (7) on the basis of chemical, mass spectrometric (-ve ESI-MS) and spectroscopic (UV, (1)H-, (13)C NMR, (1)H,(1)H-, (1)H,(13)C-COSY, (1)H,(1)H-TOCSY and HMBC) analyses. Grandinin (the major compound) showed radical scavenging properties by its reaction with 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical [EC(50) = 4.3 +/- 0.3 micro g mL(-1)]. It was found to be relatively nontoxic in mice [LD(50) = 316 mg Kg(-1) b.wt.]. It exhibited a significant dose-dependent (35-70 mg Kg(-1)) hypoglycemic effect by significantly reducing blood glucose level in basal condition and after heavy glucose load in normal mice. Moreover, it reduced the elevated blood glucose level in STZ-induced diabetic mice. In addition, grandinin reduced the elevated blood urea nitrogen and serum lipid peroxides in STZ-induced diabetic mice.

Iridoids from Phlomis aurea Decne growing in Egypt.

A new iridoid gentiobioside (4, assigned the name phlomiside) was isolated from the leaves of Phlomis aurea growing in Egypt, in addition to auroside (1), lamiide (2), 8-epi-loganin (3), forsythoside B (5), quercetin-3-O-beta-D-glucopyranoside (6) and kaempferol-3-O-beta-D-glucopyranosyl-(1-6)-beta-D-glucopyranoside (7). Structures of these compounds were elucidated by conventional methods of analysis as well as by different spectroscopic techniques.

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.

Flavonoids of Melaleuca quinquenervia.

From the leaves of Melaleuca quinquenervia (Clav.) S. T. Blake, the new flavonoid 5,7,3',4'-tetrahydroxyflavone 2'-O-beta-D-glucopyranuronide, as well as eight known flavonol glycosides have been isolated and characterized. The structures were established by chromatography, chemical degradation and UV spectroscopy and confirmed by ESI-MS and NMR spectroscopy. This is the first report on the isolation and identification of these flavonoids in the genus Melaleuca.

Bioactivity studies of Salvia transsylvanica (Schur ex Griseb) grown in Egypt.

Some pharmacological effects of the ethanol extract of Salvia transsylvanica (Schur ex Griseb) were experimentally investigated. The tested extract of the plant proved to be relatively nontoxic (LD50 = 4.437 g/kg b.wt.). The extract induced significant analgesic, antipyretic, antiepileptic, antiinflammatory, antiulcerogenic, as well as tranquillizing activities, besides increasing the bleeding time and exhibiting no central skeletal muscle relaxant effect compared with control groups and standard drugs.

Study into wild Egyptian plants of potential medicinal activity. Ninth communication: hypoglycaemic activity of some selected plants in normal fasting and alloxanised rats.

31 desert plants belonging to 17 families were collected from different Egyptian localities. 21 plants extracts were orally given to normal rats, and 15 were tested on fasted and to alloxanised rats. The results were compared with a standard oral hypoglycaemic drug (Daonil, Hoechst) used as a positive control. The following findings were obtained: 8 plants exhibited persistent hypoglycaemic effects, Lycium shawii, Salvia (S.) aegyptiaca, Pergularia tomentosa, Convolvulus (C.) althaeoides, Haloxylon salicornicum, Ephedra alata, Scrophularia deserti, and Crotalaria aegyptiaca. Transient hypoglycaemic effects appeared only 1 hour after administration in response to 4 plants, Silena succulenta, Lygos raetam, C. lanatus, and Pulicaria incisa. In the cases of Ochradenus baccatus and Zygophyllum album, slow hypoglycaemic activity was produced and appeared 3 hours after administration. 5 plants showed hypoglycaemic effects viz, Thymus capitatus, Launaea nudicaulis, Conyza dioscorides, Nitraria retusa, and Limonium tubiflorum. Among the 15 plant extracts tested on alloxanised diabetic rats only 4 showed hypoglycaemic effects more potent than those of the administered dose of Daonil. These were Matthiola livida, S. aegyptiaca, Astragalus species, and Arthrocnemum glaucum. The hypoglycaemic effect of S. aegyptiaca in fasting rats has been confirmed also in alloxanised diabetic animals. This emphasises the importance of conducting both experiments in order to obtain a reliable conclusion.

The essential oil of olibanum.

The essential oil of the oleogum resin "Olibanum" was prepared by direct steam distillation as well as by steam distillation of an N-hexane extract. Physical and chemical constants of the oil were determined. GC-MS was used for the analysis of the oil. Thirty-three components were identified in the steam distilled oil by their Kováts indices on stabilized OV-1 columns and by mass spectral data. The oil contains 62.1% esters, 15.4% alcohols, 9.9% monoterpene hydrocarbons, and 7.1% diterpenes. Certain minor constituents of the steam distilled oil failed to show up in the oil prepared by steam distillation of the N-hexane extract. Both oils exhibit antimicrobial activity, the activity of the steam distilled oil being higher than that of the oil prepared by steam distillation of the N-hexane extract.

PMR assay of natural products in pharmaceuticals-III Assay of griseofulvin.

A rapid, accurate and specific PMR method for the determination of griseofulvin in the bulk drug, tablets and dry suspension powder has been developed. The determination is based on the integration of the 4- and 6-methoxy protons of griseofulvin, relative to that of the methyl protons of acetanilide (internal standard).