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SummaryThe 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,β-unsaturated compounds.

BackgroundThe extracts from the aerial parts of Portulaca quadrifida have been reported to show the total flavonoid content, antioxidant and antibacterial activities.ResultsOur 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.ConclusionsThe 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.

BackgroundThe extracts from the leaves of Otostegia integrifolia have been reported to show phytochemical analysis, total flavonoid content, antioxidant and antibacterial activities.ResultsOur 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.ConclusionsThe 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.

ABSTRACT.Erythrina caffra is an important medicinal plant native to South Africa. Its stem bark was investigated for the flavonoid constituents and biological activity. Some isolated flavonoids, 3, 5, 6, 8, 9, 10, 11, 12, 13, 15 and 16 were found to be active against the human cervix carcinoma KB-3-1 cells with IC50 values in the micromolar range. Compounds 8, 9, 11, 13 and 15 also showed weak to moderate antibacterial activity against some organisms using the disc diffusion assay at loadings of 62.5 μg/disc (8, 11) and 125 μg/disc (9, 13, 15).