Herbal drugs are widely used in the primary health care system now-a-days and the use is increasing day by day. Thus extensive research to confirm the bioactivity of plant extract is very essential. The aim of this research was to determine the antitumor and cytotoxic actions of solvent-solvent partitioned fraction (n-hexane, ethyl acetate and hydro-methanol) of the methanol extract of root of Tremaorientalis. The antitumor activity of different fractions of plant extract was evaluated by potatodisc bioassay method where Agrobacterium tumefaciens was used to induce tumor on potato disc. On the other hand, the cytotoxic effect was determined by brine shrimp lethality bioassay technique. The ethyl acetate fraction of the plant extract showed 35.51% and 62.89% inhibition of tumor formation in potato disc bioassay method at 50 µg/disc and 100 µg/disc respectively. The hydro-methanol extract showed 37.51% inhibition of tumor formation at 100 µg/disc while at 50 µg/disc no significant inhibition was observed. In contrast, n-hexane fraction did not show any antitumor activity. In cytotoxic study by brine shrimp lethality bioassay, the lethal concentration-50 (LC50) value of the n-hexane, ethyl acetate and hydro-methanol fraction was 1377.03 µg/ml, 11.67 µg/ml and 48.62 µg/ml respectively. Ethyl acetate and hydro-methanol fractions of the solvent-solvent partitioned methanol extract of T. orientalis showed high antitumor and cytotoxic effect. These fractions are highly promising for further exploration to identify the bioactive compounds.
