The present study evaluated the antiviral activity of Bidens pilosa L. var. minor (Blume) Sherff and Houttuynia cordata Thunb., using cytotoxicity test with XTT-based colorimetric assay. BCC-1/KMC cells were infected with herpes simplex virus (HSV) and then were cultured with hot water extract of B. pilosa (HWBP) or H. cordata (HWHC). Results showed that HWBP significantly inhibited the replication of HSV at a concentration of 100 microg/ml (11.9% for HSV-1, p < 0.01; 19.2% for HSV-2, p < 0.005), whereas HWHC had the same effect at a concentration of 250 microg/ml (10.2% for HSV-1, p < 0.05; 32.9% for HSV-2, p < 0.005). The ED50 of HSV type 1 (HSV-1) and HSV type 2 (HSV-2) for HWBP was 655.4 microg/ml and 960 microg/ml respectively, for HWHC it was 822.4 microg/ml and 362.5 microg/ml respectively. Both drugs had selective indexes above 1.04. H. cordata had better effect against HSV-2 than HSV-1, and had a low ED50 against HSV-2. We suggest that H. cordata might be a useful medicinal plant against infection of HSV-2.

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.

Medicinal plants have been historically used as treatment for different kinds of human diseases. In this study, hot water (HW) extract of five Taiwanese traditionally used medicinal plants was evaluated for their in vitro anti-leukemic (including anti-K562, L1210, P3HR1, Raji and U937 leukemia cells) and antiviral (including HSV-1 and HSV-2) activities. Results showed that Blumea lacera exhibited broad anti-leukemic activity at magnitudes ranging from moderate to mild and Ixeris chinensis is effective at inhibiting the proliferation of K562 cells. B. lacera and Tithonia diversifolia suppressed the replication of HSV-1 and HSV-2, and had IC50 values below 100 microg/ml. The medicinal plants showed no cytotoxic effect at concentrations that inhibited HSV infection. It was, therefore, concluded that the HW extract of tested medicinal plants exhibited anti-leukemic and antiviral activities at different magnitudes of potency.