Development and validation of a high-performance liquid chromatography method for standardization of the bioactive ethyl acetate fraction of Alstonia scholaris (Linn.) R. Br. growing in Egypt.

Bio-guided fractionation of the ethanolic extract of the leaves of Alstonia scholaris (Apocynaceae) growing in Egypt was carried out to evaluate its antihyperglycemic activity in alloxan-induced diabetic rats and its hepatoprotective activity against CCl4-induced hepatotoxicity in rats. The ethyl acetate fraction of the ethanolic extract showed the highest antihyperglycemic [(133.6 +/- 4.

Bioguided isolation of pentacyclic triterpenes from the leaves of Alstonia scholaris (Linn.) R. Br. growing in Egypt.

Ethanolic and aqueous extracts of the leaves and flowers of Alstonia scholaris were evaluated for their antioxidant activity by investigating their effect on blood glutathione levels in alloxan-induced diabetic rats. The ethanolic extract of the leaves was the most active; therefore, its cytotoxicity against HepG2 cells was also tested. Promising GI₅₀ values of 1.

Flavonoids and terpenoids from Helichrysum forskahlii.

Three new flavonoids, namely helichrysone A (1), helichrysone B (2) and helichrysone C (3) were isolated from the aerial parts of Helichrysum forskahlii, together with 10 known flavonoids, three triterpenes, and one sesquiterpene. The structures of the new flavonoids 1-3 were established by 1D and 2D NMR spectral data. In addition, the antimicrobial activities of the isolated compounds were determined.