Phytotoxic and Anti-microbial activities of Flavonoids in Ocimum gratissimum

In this study, the leaves of Ocimum gratissimum have been investigated and found to contain flavonoids as part of their secondary metabolites. This observation agrees with the few available reports on the presence of flavonoids in O.gratissimum plants. The flavonoids were extracted from dried powdered leaves of Ocimum gratissimum using soxhlet extraction method. The crude extract was partially purified on column chromatography using an eluting system of formic acid and ethyl acetate in the ratio of 15:85.Qualitative tests were carried out to confirm the presence flavonoids in the O. gratissimum extract. Frothing test, as a follow up was also done on the extract to ensure the absence of saponins which are usually abundant as secondary metabolites in plants. The allelopatic investigation of the partially purified extract on bean and maize seeds germination, and on seedlings growth showed that O.gratissimum flavonoids are phytotoxic. The inhibition of the radicle and coleoptile growth was observed to be dose-dependent, and the radicles of both seeds were comparatively more inhibited. Eight human pathogenic microbes; six bacteria and two fungi were used to evaluate the antimicrobial activities of the flavonoid extract. A broad-spectrum antimicrobial effect was observed with the flavonoids. However, they had no effect on fungi growt