Flavonoids Isolated From Vietnamese Cat's Whisker Plant Orthosiphon Stamineus Benth.

From the aerial part of the Vietnamese medicinal plant Orthosiphon stamineus Benth which was collected at Thanh Tri, Ha Noi, by using several extraction, fractionation, and isolation methods (including TLC, OP_CC with SiO2, RP_C18, and sephadex LH-20…), three flavonoid-type compounds have been isolated and purified. The chemical structure of these isolated compounds are identified as 3ʹ-hydroxy-3,5,7,4ʹ-tetramethoxyflavone (1), 5,7,3ʹ,4ʹ-tetramethoxyflavone (2), and 5,7,4ʹ-trimethoxyflavone (3)based on the analyses of the combined spectroscopic data (including NMR, MS, IR, UV) and physicochemical data interpretation. This is the first time that 5,7,3ʹ,4ʹ-tetramethoxyflavone (2)and 5,7,4ʹ-trimethoxyflavone (3) have been isolated from the Vietnamese medicinal plant Orthosiphon stamines Benth