Determination of antioxidant and antimicrobial activities of the extracts of aerial parts of Portulaca quadrifida.

BACKGROUND: The extracts from the aerial parts of Portulaca quadrifida have been reported to show the total flavonoid content, antioxidant and antibacterial activities. RESULTS: Our results revealed that the total flavonoid content of methanol and chloroform extracts is 2.335 ± 0.0097 and 1.7312 ± 0.0082 mgQE/100 g respectively. The two extracts also showed good antioxidant activity and total phenolic content as well as weak to moderate antibacterial activity against some bacteria. CONCLUSIONS: The extracts the aerial parts of the P. quadrifida showed good total flavonoid content, DPPH radical scavenging activity and antibacterial activity. In addition to this, the extracts also showed the presence of some important compounds by phytochemical analysis.

Determination of antioxidant and antimicrobial activities of leaf extracts of Otostegia integrifolia.

BACKGROUND: The extracts from the leaves of Otostegia integrifolia have been reported to show phytochemical analysis, total flavonoid content, antioxidant and antibacterial activities. RESULTS: Our results revealed that the total flavonoid content of methanol and ethyl acetate extracts is 416.5 + 0.288 and 248.9 + 0.872 mgAAE/100 g respectively. The two extracts also showed good antioxidant activity as well as weak to moderate antibacterial activity against some bacteria. CONCLUSIONS: The leaf extracts from O. integrifolia showed good total flavonoid content, DPPH radical scavenging activity and antibacterial activity. In addition to this, the extracts also showed the presence of some important compounds by phytochemical analysis.

Three new isoflavonoids from Erythrina caffra.

Three new isoflavonoids, 5,7-dihydroxy-2',4'-dimethoxy-5'-(3-methylbut-2-enyl) isoflavanone (erycaffra A) (1), 5,7-dihydroxy-2',4'-dimethoxy-5'-(2-hydroxy-3-methylbut-3-enyl)isoflavanone (erycaffra B) (2), and 5,7-dihydroxy-6,8-di-(2-hydroxy-3-methylbut-3-enyl)isoflavone (erycaffra C) (3), were isolated from the stem bark of E. caffra Thunb., along with eight known compounds, namely, alpinumisoflavone (4), isoerysenegalensein E (5), beta-amyrin (6), oleanolic acid (7), octacosyl-E-ferulate (8), triacontyl-4-hydroxycinnamate (9), n-tetracosyl p-coumarate (10) and octacosan-1-ol (11). The structures were determined on the basis of spectroscopic (1D, 2D-NMR) and MS data and by comparison with literature values.

New flavonoids from the stem bark of Erythrina caffra Thunb.

Three new flavonoids 5,7-dihydroxy-2',4'-dimethoxy-5'-formylisoflavanone (erycaffra E) (1), 5,7-dihydroxy-3'-(2″-hydroxy-3″-methylbut-3-enyl)-5'-(3‴-hydroxy-3‴-methyl-trans-but-1-enyl)-4'-methoxyflavanone (erycaffra D) (2) and 5,7-dihydroxy-4'-methoxy-3',5'-di-(3″-hydroxy-3″-methyl-trans-but-1-enyl)flavanone (erycaffra F) (3) were isolated from the stem bark of Erythrina caffra along with four known compounds, namely 5,4'-dihydroxy-6-(3″-methylbut-2″-enyl)-5‴-hydroxyisopropyldihydrofurano[2‴,3‴:7,8]isoflavone (isosenegalensein) (4), 5,7-dihydroxy-4'-methoxy-3'-(3″-methylbut-2-enyl)-5'-(3‴-hydroxy-3‴-methylbut-1-enyl)flavanone (burttinone) (5), 5,4'-dihydroxy-5″-hydroxyisopropyldihydrofurano[2‴,3‴:7,6]isoflavone (erythrinin C) (6) and 5,4'-dihydroxy-6″-hydroxymethyl-6″-methylpyrano[2″,3″:6,7]isoflavone (erysubin B) (7). The structures were determined on the basis of spectroscopic data (1D, 2D NMR and MS) and by comparison with literature values.

Reactions of salicylaldehyde and enolates or their equivalents: versatile synthetic routes to chromane derivatives.

The reported methodologies for the synthesis of chromane derivatives through the reaction of salicylaldehyde and enolates are discussed. The enolates and their equivalents involved in the reactions discussed in this article were derived from ketones, nitroalkanes, malononitrile and α,ß-unsaturated compounds.