The crude ethanol extracts (stem and fruits), their fractions and two triterpenes, $eta$-Amyrin and 12-Oleanene 3$eta$, 21$eta$-diol, isolated as a mixture from the chloroform soluble fraction of an ethanolic extract of Duranta repens stem, were evaluated for antibacterial, antifungal activities by the disc diffusion method and cytotoxicity by brine shrimp lethality bioassay. The structures of the two compounds were confirmed by IR, $^1H$-NMR, $^{13}C$-NMR and LC-MS spectral data. The chloroform soluble fraction of stem and ethanol extract of fruits possess potent antishigellosis activity and also exhibited moderate activity against some pathogenic bacteria and fungi but the isolated compound 1 (mixture of $eta$-Amyrin and 12-Oleanene 3$eta$, 21$eta$-diol) showed mild to moderate inhibitory activity to microbial growth. The minimum inhibitory concentrations (MICs) of the extracts (stem and fruits), their fractions and compound 1 were found to be in the range of 32$sim$128 ${mu}g/ml$. The chloroform soluble fractions of stem and ethanol extract of fruit showed significant cytotoxicity with $LC_{50}$ value of 0.94 ${mu}g/ml$ and 0.49 ${mu}g/ml$, respectively against brine shrimp larvae.