10.22376/ijpbs.2019.10.1.p1-12 Volume 6 Issue 3 2015 (July - September) lessThan i greaterThan Phyllanthus niruri lessThan /i greaterThan L. (Euphorbiaceae), known as "quebra-pedra" (Portuguese for "stonebreaker"), is an herb used for kidney disorders.Whole plants have been used in traditional medicine for treatment of jaundice, asthma, hepatitis and malaria. The present study was designed to determine the anticancer activity of flavonoid isolated from the acetone extract of the aerial part of lessThan i greaterThan P. niruri lessThan /i greaterThan against human lung cancer cell line (A lessThan sub greaterThan 549 lessThan /sub greaterThan ).MTT assay based cytotoxic activity study against human lung cancer cell line (A lessThan sub greaterThan 549 lessThan /sub greaterThan ) was conducted to evaluate the potent activity of flavonoid isolated from lessThan i greaterThan P. niruri. lessThan /i greaterThan TLC and GC- MS analysis were recorded to confirmthe presence of flavonoids in acetone extracts.Flavonoids isolated from the acetone extract of the aerial part of lessThan i greaterThan P.niruri lessThan /i greaterThan showed cytotoxic activity against the human lung cancer cell line (A lessThan sub greaterThan 549 lessThan /sub greaterThan ) and the inhibitory concentration at 50% growth (IC lessThan sub greaterThan 50 lessThan /sub greaterThan ) was found to contain IC lessThan sub greaterThan 50 lessThan /sub greaterThan = 30.70±0.81µg/mL respectively. The results indicated that the flavonoids isolated from the lessThan i greaterThan P.niruri lessThan /i greaterThan showed cytotoxic activity which can be effectively employed in anticancer treatment. Cytotoxic study suggested that flavonoid from the acetone extract of the aerial part of lessThan i greaterThan P. niruri lessThan /i greaterThan was found to contain maximum inhibition of 66.6% at 7.8µg/mL concentration. N. PADMAPRIYA AND T.V. POONGUZHALI Phyllanthusniruri, flavonoids, MTT assay, cytotoxicity, GC-MS analysis 296-304