Minerals salt composition and secondary metabolites of Euphorbia hirta Linn., an antihyperglycemic plant.

Phytochemical study and research on acute toxicity were performed on the aerial parts (leaves and stems) of Euphorbia hirta Linn. The phytochemical screening and chromatography revealed the presence of saponin, sterol, terpene, alkaloids, polyphenols, tannins and flavonoids and especially mucilage. The evaluation of total polyphenols and total flavonoids gave 120.97 ± 7.07 gallic acid equivalents (GAE) mg/g (mg of GAE/g of extract) of dry extract and 41.4 ± 0.5 mg quercetin equivalent per gram (QE/g) (mg of QE/g of plant extract) of dry extract respectively. The physicochemical study revealed moisture content of 7.73% ± 0.00%, total ash 7.48% ± 0.03%. Sulfuric ash 9.05% ± 0.01%, hydrochloric acid insoluble ash of 0.8% ± 0.02%. The search for minerals salt revealed the presence of Cr, Zn, K, Ca and Mg having an important role in glucose metabolism. The acute toxicity study showed that the toxic dose may be above 3000 mg/kg. The results of these studies indicate that extracts from the leaves and stem of E. hirta Linn. contains trace elements and minerals salt and bioactive secondary metabolites which explain their therapeutic uses for treating diabetes mellitus.

Anti-angiogenic activity of Entada africana root.

Entada africana roots are used in African traditional medicine for various diseases including inflammation. This application may be mediated through anti-angiogenic effects. Thus, in this study the anti-angiogenic activity of E. africana root extracts (n-hexane, chloroform, chloroform/methanol and methanol) was preliminarily evaluated by the quantitative determination of endogenous alkaline phosphatase in zebrafish embryos. A bioactivity-guided fractionation of chloroform/methanol extract yielded apigenin and robinetin as the main constituents from the most active fractions. In addition, a marked reduction on capillary formation was evidenced in chick chorioallantoic membrane after treatment with the active fractions or isolated compounds. Results obtained in this study suggest that the anti-angiogenic effects of E. africana root may account for its use in inflammatory diseases and other related pathological conditions.

Bioassay-guided isolation of proanthocyanidins with antiangiogenic activities.

The proangiogenic members of the vascular endothelial growth factor (VEGF) family and related receptors play a central role in the modulation of pathological angiogenesis. In order to identify plant compounds able to interfere in the VEGFs/VEGFR-1 (Flt-1) recognition by VEGF family members, the extracts of the aerial parts of Campsiandra guayanensis and Feretia apodanthera were screened by a competitive ELISA-based assay. By using this bioassay-oriented approach five proanthocyanindins, including the new natural compounds (2S)-4',5,7-trihydroxyflavan-(4ß→8)-afzelechin (1) and (2S)-4',5,7-trihydroxyflavan-(4ß→8)-epiafzelechin (2) and the known geranin B (3), proanthocyanidin A2 (4), and proanthocyanidin A1 (5), were isolated. The study of the antiangiogenic activities of compounds 1-5 using ELISA and SPR assays showed compound 1 as being the most active. The antiangiogenic activity of 1 was also confirmed in vivo by the chicken chorioallantoic membrane assay. Our results indicated 1 as a new antiangiogenic compound inhibiting the interaction between VEGF-A or PlGF and their receptor VEGRF-1.

Antiproliferative triterpene saponins from Entada africana.

Nine new ester saponins (1-9) were isolated from the roots of Entada africana. Their structures were elucidated by 1D and 2D NMR experiments including 1D and 2D TOCSY, DQF-COSY, HSQC, and HMBC spectroscopy, as well as ESIMS analysis, and chemical methods. The aglycon moieties were found to be echinocystic acid for compounds 1, 2, 4-6, 8, and 9 and acacic acid for 3 and 7. All isolated compounds were tested for their antiproliferative activity against the J774.A1, HEK-293, and WEHI-164 cell lines. Moderate to high cytotoxic potency was found for almost all compounds tested.

Pregnane glycosides from Leptadenia pyrotechnica.

The whole plant of Leptadenia pyrotechnica afforded 18 new pregnane glycosides (1-18) with sarcostin, 11-hydroxysarcostin, and deacetylmetaplexigenin as the aglycon moieties and acetyl, benzoyl, cinnamoyl, p-coumaroyl, and nicotinoyl ester moieties linked at C-12 and/or C-20 of the aglycon and hexopyranose, 6-deoxy-3-O-methylhexopyranose, and 2,6-dideoxy-3-O-methylhexopyranose sugars linked at C-3 of their aglycon. The structures of these compounds were elucidated by spectroscopic data interpretation and from chemical evidence. The antiproliferative activity of all compounds was evaluated using three continuous murine and human culture cell lines, J774.A1, HEK-293, and WEHI-164. Compounds having deacethylmetaplexigenin as aglycon and a cinnamoyl ester moiety linked at C-12 were the most active constituents.

Antiproliferative activity of Pteleopsis suberosa leaf extract and its flavonoid components in human prostate carcinoma cells.

In this work we describe the chemical composition of Pteleopsis suberosa (Combretaceae) leaf extract and its biological activity against androgen-insensitive human prostate cancer cells (DU-145). The methanol extract of the plant leaves exhibited activity against tumor cell growth. Fractionation of this active extract led to the isolation and identification of sixteen flavonoids, including gallocatechin and flavonols having kaempferol, quercetin, and myricetin as aglycones. Among the myricetin derivatives, myricetin 3-O-(3''-acetyl)-alpha-L-arabinopyranoside (1) and myricetin 3-O-(4''-acetyl)-alpha- L-arabinopyranoside (2) are now reported for the first time. Six compounds, myricetin 3-O-alpha- L-rhamnopyranoside (4), myricetin 3-O-beta-D-galactopyranoside (7), myricetin 3-O-(6''-galloyl)-beta-D-galactopyranoside (9), myricetin 3-O-beta-D-xylopyranoside (10), myricetin 3-O-alpha-L-arabinofuranoside (12), and gallocatechin (14), exhibited significant activity, reducing cell vitality and inducing apoptosis via the caspase-dependent pathway in DU-145 cells that can be, in part, correlated to modulation of redox-sensitive mechanisms.

Anti-inflammatory activity of verminoside from Kigelia africana and evaluation of cutaneous irritation in cell cultures and reconstituted human epidermis.

Kigelia africana is a plant used in Africa for anti-inflammatory, anti-microbial, and anti-skin-aging effects. Various papers have reported on the composition and biological activities of its CH2Cl2 extracts and dermal formulations. Chemical analysis of a polar extract of fruit from K. africana indicated the presence of verminoside (1), an iridoid, as a major constituent, and of a series of polyphenols such as verbascoside (2). In vitro assays showed that 1 had significant anti-inflammatory effects, inhibiting both iNOS expression and NO release in the LPS-induced J774.A1 macrophage cell line. Cytotoxicity and cutaneous irritation of the extract and of compounds 1 and 2 were investigated. The crude extract and 1 did not affect cell viability in vitro either in cells grown in monolayers (ML) or in the reconstituted human epidermis (RHE, 3D) model; neither caused release of pro-inflammatory mediators or histomorphological modification of RHE.

New pregnane glycosides from Caralluma dalzielii.

Twenty-seven new pregnane glycosides were isolated from the whole plant of Caralluma dalzielii, and their structures elucidated from extensive 2D NMR analysis as well as ESI-MS experiments. All isolated compounds were tested for their antiproliferative activity on J774.A1, HEK-293, and WEHI-164 cell lines. Moderate to high potency of cytotoxicities were found in almost all tested compounds, confirming the significant cytotoxic activity of pregnane glycosides.

Chemical composition and antioxidant activity of phenolic compounds from wild and cultivated Sclerocarya birrea(Anacardiaceae) leaves.

A quantitative study of the phenolic constituents of wild and cultivated leaves of Sclerocarya birrea(Anacardiaceae) was carried out by HPLC-UV/PDA and LC-MS. Phytochemical analysis of the methanol extract of wild plants led to the isolation of one new flavonol glycoside, quercetin 3-O-alpha-l-(5' '-galloyl)-arabinofuranoside (1), and eight known phenolic compounds; two epicatechin derivatives were also isolated from the same extract of the cultivated species. The antioxidant activity of all isolated compounds was determined by measuring free radical scavenging effects using the Trolox equivalent antioxidant capacity assay and the coupled oxidation of beta-carotene and linoleic acid (autoxidation assay).