Cytotoxic natural products from thai plants: a recent study

Potent Antiproliferative Effect on Liver Cancer of Medicinal Plants Selected from the Thai/Lanna Medicinal Plant Recipe Database "MANOSROI III"

Thai/Lanna medicinal plant recipes have been used for the treatment of several diseases including liver cancer. In this study, methanolic extracts (MEs) of 23 plants were tested for antiproliferative activity on human hepatoma cell line (Hep G2) by the sulforhodamine B (SRB) assay. Nine MEs with potent antiproliferative activity (IC50 < 100 µg/mL) were obtained and further semipurified by liquid/liquid partition extraction. The semipurified fractions were tested for the antiproliferative and antioxidative activities. ME of Stemona collinsae and the semipurified extract and methanol-water fraction (MF) of Gloriosa superba gave the highest antiproliferative activity on HepG2 which were 4.79- and 50.07-fold cisplatin, respectively. The semipurified fractions showed an increased antiproliferative activity. MF of Caesalpinia sappan and HF of Senna alata showed the highest free radical scavenging and metal chelating activities, respectively. The compound in n-hexane fraction (HF) of Ventilago denticulata which showed an increase in antiproliferative activity comparing to its ME was isolated and identified as emodin. This study has demonstrated the potential of the ME from S. collinsae, MF from G. superba, and emodin isolated from V. denticulata, for further development as an antiliver cancer agent.

In vitro anti-proliferative activity on colon cancer cell line (HT-29) of Thai medicinal plants selected from Thai/Lanna medicinal plant recipe database "MANOSROI III"

ETHNOPHARMACOLOGICAL RELEVANCE

Thai/Lanna region has its own folklore wisdoms including the traditional medicinal plant recipes. Thai/Lanna medicinal plant recipe database "MANOSROI III" has been developed by Prof. Dr. Jiradej Manosroi. It consists of over 200,000 recipes for all diseases including cancer. To investigate the anti-proliferative and apoptotic activities on human colon cancer cell line (HT-29) as well as the cancer cell selectivity of the methanolic extracts (MEs) and fractions of the 23 selected plants from the "MANOSROI III" database.

MATERIALS AND METHODS

The 23 selected plants were extracted with methanol under reflux and evaluated for their anti-proliferative activity by sulforhodamine B assay. The 5 plants (Gloriosa superba, Caesalpinia sappan, Fibraurea tinctoria, Ventilago denticulata and Psophocarpus tetragonolobus) with potent anti-proliferative activity were fractionated by liquid-liquid partition to give 4 fractions including each hexane (HF), methanol-water (MF), n-butanol (BF) and water (WF) fractions. They were tested for anti-proliferative activity and cancer cell selectivity. The ME and fractions of G. superba which showed potent anti-proliferative activity were further examined for morphological changes and apoptotic activities by acridine orange (AO)/ethidium bromide (EB) staining.

RESULTS

The ME of G. superba root showed active with the highest anti-proliferative activity at 9.17 and 1.58 folds of cisplatin and doxorubicin, respectively. After liquid-liquid partition, HF of V. denticulata, MFs of F. tinctoria, V. denticulata and BF of P. tetragonolobus showed higher anti-proliferative activities than their MEs. The MF of G. superba indicated the highest anti-proliferative activity at 7.73 and 1.34 folds of cisplatin and doxorubicin, respectively, but only 0.86 fold of its ME. The ME and HF, MF and BF of G. superba and MF of F. tinctoria demonstrated high cancer cell selectivity. At 50 µg/ml, ME, HF, MF and BF of G. superba demonstrated higher apoptotic activities than the two standard drugs.

CONCLUSIONS

This present study has not only confirmed the traditional use of the Thai/Lanna medicinal plant recipes for cancer treatments, but also the potential of the selected plant, G. superba for the further development as a modern anti-cancer drug.