Pharmacologyonline 2: 5368 (2011) Khade et al. 53 ATICACER ACTIVITY OF THE ETHAOLIC EXTRACTS OF AGAVE AMERICAA LEAVES. Ketan V. Khade, Harikesh Dubey*, Chandrashekhar R. Tenpe, Pramod G. Yeole, Angad M. Patole Institute of Pharmaceutical Education and Research (IPER), Wardha (MS) 442 001, India. E/mail: dubey.harikesh@gmail.com Summary The present study was designed to determine the anticancer activity of the ethanolic extract of leaves of Agave americana L. (Agavaceae) using three reported methods. For brine shrimp lethality bioassay ten nauplii were placed in test tube filled with 5 ml total volume of artificial sea water and different concentrations (100, 500, 1000, 2000, 5000 µg/ml) of ethanolic extract of Agave americana leaves in a set of test tubes per dose. After 24 hours, live nauplii were counted and LC 50 value was estimated. In Allium cepa root meristem model, onion bulbs were suspended inside 100 ml beakers at different concentration (1 mg/ml and 10 mg/ml) of extract. The percentage root growth inhibition after treating with ethanolic extract at 48 and 96 hrs was determined. MTT assay have been utilised to measure the antitumor activity of ethanolic extract of A. americana leaves by using PA/1 human cell line of ovarian teratocarcinoma. Brine shrimp lethality bioassay (LC 50 = 923.10g/ml), Allium cepa root meristem model and MTT assay (IC 50 =0.01µg/ml) showed potent cytotoxic and anticancer activity of ethanolic extract of A. americana leaves. The ethanolic extract of A. americana leaves has a cytotoxic and antitumor activity. Therefore, this plant has potential to be utilized for the development of novel anticancer drug leads. Keywords: MTT assay (3/(4, 5/dimethylthiazol/2/yl)/2,5/diphenyltetrazolium bromide) assay, Brine shrimp lethality bioassay (BSLB), teratocarcinoma, PA 1 cell line.