Cancer is a leading cause of death worldwide and sustained focus is on the discovery and development of newer and better tolerated anticancer drugs especially from plants. The sulforhodamine B (SRB) in vitro cytotoxicity assay, sarcoma-180 (S-180) ascites and solid tumor, and L1210 lymphoid leukemia in vivo models were used to investigate the anticancer activity of root extracts of Aristolochia ringens Vahl. (Aristolochiaceae; mə dou líng). AR-A001 (IC50 values of 20 μg/mL, 22 μg/mL, 3 μg/mL, and 24 μg/mL for A549, HCT-116, PC3, and THP-1 cell lines, respectively), andAR-A004 (IC50 values of 26 μg/mL,19.5 μg/mL,12 μg/mL, 28 μg/mL, 30 μg/mL, and 22 μg/mL for A549, HCT-116, PC3, A431, HeLa, and THP-1, respectively), were observed to be significantlyactive in vitro. Potencywashighest withAR-A001 andAR-A004 for PC3withIC50values of 3 μg/mL and 12 μg/mL, respectively. AR-A001 and AR-A004 produced significant (p < 0.05e0.001) dose-dependent inhibition of tumor growth in the S-180 ascites model with peak effects produced at the highest dose of 120mg/kg. Inhibitionvalueswere 79.51%and89.98%forAR-A001andAR-A004, respectively. Inthe S-180solid tumormodel, the inhibition of tumor growth was 29.45% and 50.50% for AR-A001 (120mg/kg) and AR-A004 (110 mg/kg), respectively, compared to 50.18% for 5-fluorouracil (5-FU; 20 mg/kg). AR-A001 and AR-A004 were also significantly active in the leukemia model with 211.11% and 155.56% increase in mean survival time (MST) compared to a value of 211.11% for 5-FU. In conclusion, the ethanolic (AR-A001) and dichloromethane: methanol (AR-A004) root extracts of AR possess significant anticancer activities in vitro and in vivo.
