Cytotoxic constituents from Andrographis paniculata induce cell cycle arrest in jurkat cells

Herbal medicines are now attracting attention as potential sources of anticancer agents. Andrographis paniculata is a traditionally used anticancer herb in Indian and Chinese herbal medicine. Phytochemical investigation of the ethanol extract of the aerial parts of this herb resulted in the isolation of 14 compounds including flavonoids and labdane diterpenoids. This is the first isolation of compound 6 from a natural source, and the aerial parts of A. paniculata are a rich source for the molecule andrographolide (9, 1.375%, w/w). The structures of the isolated compounds were established by means of spectral data. The cytotoxic activities of these isolates were evaluated against Jurkat, PC‐3, HepG2 and Colon 205 tumor cells, and normal cells PBMCs. The bioactivity assays showed that metabolites 1–4 and 6–8 exhibited moderate cytotoxic activity against Jurkat, PC‐3 and Colon 205 cell lines, where compound 6 had IC 50 values of 0.05, 0.07 and 0.05 m m , respectively. Further, among these effective compounds, 3 and 6 selectively blocked the cell cycle progression at G0/G1, while 1, 2, 4, 7 and 8 blocked the same at G2/M phase of the Jurkat cell line. This is the first cell cycle analysis for the above mentioned isolates on the Jurkat cells. Therefore, these plant‐derived compounds may play a role in the prevention and/or management of cancer. Copyright © 2008 John Wiley & Sons, Ltd.