Two New Flavonoids and Biological Activity of Astragalus abyssinicus (Hochst.) Steud. ex A. Rich. Aerial Parts.

2 new flavonoid glycosides, kaempferol 3-O-(4",6"-di-O-α-L-rhamnopyranosyl)-ß-D-glucopyranoside (1) and quercetin 3-O-(4",6"-di-O-α-L-rhamnopyranosyl)-ß-D-glucopyranoside (2), were isolated from the n-butanol soluble fraction of the methanol extract (BF) of Astragalus abyssinicus aerial parts, together with 3 known compounds, rutin (3), kaempferol 3-O-ß-D-rutinoside (4) and 5,7,4'-trihydroxy-3'-methoxyisoflavone (5). The structures of the isolated compounds were characterized on the basis of UV, NMR and negative ESI-MS analyses. The BF fraction showed in vitro weak antibacterial activity against Staphylococcus aureus, while 2 and 3 exhibited in vitro antioxidant activity higher than ascorbic acid using DPPH free radical scavenging activity method.

Leaf extract of Markhamia platycalyx: polyphenolic profile, acute toxicity, anti-inflammatory, hepatoprotective and in vitro antioxidant activities.

10 polyphenols were identified from 80% aqueous methanol extract (AME) of Markhamia platycalyx [(Baker) Sprague] leaf. Their structures were characterized as protocatechuic acid (1), E-caffeic acid (2), E-methyl caffeate (3), isoverbascoside (4), verbascoside (5), jacraninoside-I (6), cosmosiin (7), cinaroside (8), luteolin (9) and apigenin (10) based on chemical and extensive spectral studies (UV, ESI-MS, (1)H, (13)C and 1D/2D NMR). Biological evaluation indicated that AME is non-toxic to the experimental animals. It exhibited a significant inhibition of oedema after 1, 2, 3 and 4 h for all examined doses (250, 500 and 1 000 mg/kg). In comparison with silymarin, the AME demonstrated a significant hepatoprotective effect in the form of high reduction in elevated ALT and AST serum levels in regard to paracetamol treated group. As well as, it revealed a marked significant scavenging activity by 62.9, 82.5, 88.3, 83.7 and 83.7%, for the concentrations 20, 40, 60, 80 and 100 mg/ml of the extract, respectively, relative to L-ascorbic acid (86.8%), which was used as a reference antioxidant drug.

Novel macrocyclic monoterpene glycosides from bioactive extract of Parkinsonia aculeata L.

Five novel macrocyclic monoterpene O-glycosides, parkinsenes A-E (1-5), and eleven known phenolic metabolites including three 3-O-glycosylflavonols (6-8), five C-glycosylflavones (9-13), p-hydroxybenzoic acid (14), esculetin (15), and diosmetin (16) were isolated from the leaves and small twigs of Parkinsonia aculeata L. (Fabaceae). Their structures were established by chemical and spectroscopic analyses (UV, ESI-MS, and 1D/2D NMR). The investigated 80 % aqueous methanol extract (AME) showed significant analgesic, antipyretic, anti-inflammatory, hepatoprotective, hypoglycemic, hypocholesterolemic, and antioxidant activities in a dose-dependent manner using two different doses 250 and 500 mg/kg b. wt.

Two new flavonol glycosides from leaves of Koelreuteria paniculata.

Two new flavonol glycosides were isolated from dried leaves of Koelreuteria paniculata Laxm. (Sapindaceae) and characterized as 6,8-dihydroxy-afzelin and afzelin 3"-O-gallate, based on chemical and spectral evidences, in addition to nine known polyphenolic metabolites, including eight isolated for the first time from this species.