Thunbergia grandiflora(Acanthaceae) has been investigated for isolation of its secondary metabolites and evaluation of biological activities of the crude extractive. One compound had been isolated, which was identified by extensive analyses of resolution NMR spectral data. The powdered leaf of T. grandiflora was extracted separately with methanol. The solid extract was then subjected to vacuum liquid chromatography (VLC). Repeated chromatographic separation and purification the leaves of Thunbergia grandiflora afforded one flavonoid named 5 hydroxy-4',6,7- trimethoxy flavone, C18H16O6. The Methanolic crude extract of Thunbergia grandiflora showed moderate analgesic activity. Out of all the samples only chloroform fraction methanolic crude extract were appeared mild potent in terms of both zone of inhibition & spectrum of activity against some gram positive, gram negative bacteria and fungi. In antidiarrhoeal test and brine shrimp lethality bioassay, hexane, carbon tetrachloride, chloroform and aqueous fractions exhibited insignificant activities whereas Carbon tetra chloride fraction showed some hypoglycemic effect at a dose of 300 mg/kg body weight compared to control group.