Antileukemic activity of Bidens pilosa L. var. minor (Blume) Sherff and Houttuynia cordata Thunb.

To evaluate the anti-leukemic activity of Bidens pilosa L. var. minor (Blume) Sherff and Houttuynia cordata Thunb., cytotoxicity tests with an XTT-based colorimetric assay were used. Five leukemic cell lines, namely L1210, U937, K562, Raji and P3HR1, were cultured with hot water extracts of B. pilosa var. minor or H. cordata. Hot water extracts of B. pilosa var. minor inhibited these five leukemic cells with IC50s between 145 microg/ml and 586 microg/ml. The effect was greatest on four cell lines, namely L1210, P3MR1, Raji and K562, with IC50s below 200 microg/ml and a selective index of more than 5. Hot water extract of H. cordata inhibited these five leukemic cells with IC50s between 478 microg/ml and 662 microg/ml. The selective index was between 1.5 and 2.1. B. pilosa var. minor was more effective than H. cordata in inhibiting most of the leukemic cells in our study. We suggest that B. pilosa L. var. minor (Blume) Sherff may prove to be a useful medicinal plant for treating leukemia.

Antioxidant and free radical scavenging effects of baicalein, baicalin and wogonin.

Xanthine oxidase inhibitors are known to be therapeutically useful for the treatment of hepatitis and brain tumor. Baicalein, baicalin and wogonin, isolated from Scutellaria rivularis, have been reported to exhibit a strong activity on xanthine oxidase inhibition. In this study, their antioxidant activity was evaluated by modified xanthine oxidase inhibition and cytochrome c reduced methods. The results showed that the order of activity on xanthine oxidase inhibition was baicalein > wogonin > baicalin, IC50 = 3.12, 157.38 and 215.19 microM, respectively, whereas the activity on cytochrome c reduction was baicalin > wogonin > baicalein (IC50 = 224.12, 300.10 and 370.33 microM, respectively). In another study, an electron spin resonance (ESR) technique was used to further confirm the direct free radical scavenging activity. Both baicalein and baicalin demonstrated a strong activity on eliminating the superoxide radical (.O2-) (baicalein: 7.31 x 10(4) u/g; baicalin: 1.19 x 10(5) u/g). The IC50 of baicalein was 2.8 fold higher than that of baicalin. However they had no significant effect on scavenging hydroxyl radical (.OH). The present results demonstrated that baicalein and baicalin posed a different pathological pathway. The antioxidant function of baicalin was mainly based on scavenging superoxide radical whilst baicalein was a good xanthine oxidase inhibitor.