A New Flavone from Erythrina suberosa, its Biological Screening and Application as pH Indicator

A new flavone is isolated, characterized and its pH indicator property is studied for titration between strong/weak acids and bases. Flavone (Z)-3-hydroxy-2-(4-hydroxy-3-methoxyphenyl)-5-(isopentyloxy)-7-methoxy-6-(2-methylpent-1-en-1- yl) chromenylium chloride has been isolated by extracting ether and methanol. Compound is separated using column chromatography and identified with the help of spectroscopic techniques such as mass, [sup.1]HNMR, IR and UV. Compound is also screened for its antibacterial and anti-fungal activity from the flower extract of Erythrina suberosa. Activity of the isolated compound is observed for E Coli bacteria as a gram-negative organism. The compound shows significant color change in acidic and alkaline medium and its potential as pH indicator is encouraging. Keywords: anti-bacterial; anti-fungal activity; erythrina suberosa; flavone; pH indicator