Cytotoxicity (IC50)a of the extracts of P. watsonii and fractions and sub-fractions of PW-H.

aData are presented as mean ± SD from 3 independent experiments, triplicate for each. Values in bold characters are considered to have cytotoxic activity (IC50 ≤ 20 µg/mL).bSelectivity index.cPW-M, PW-H & PW-E: extracts of P. watsonii in 3 different solvents, MeOH, hexane and EtOAc, respectively.dPWH-1, PWH-2,…….,PWH-10: fractions of PW-H of P. watsonii.ePPWH-1, PPWH-2,….,PPWH-8: sub-fractions from pooled fractions (PWH-4,…,PWH-8).