In vitro and in vivo bioactivities of aqueous and ethanol extracts from Helicteres angustifolia L. root.

ETHNOPHARMACOLOGICAL RELEVANCE: Helicteres angustifolia L. (H. angustifolia L.) has been used as traditional medicine in the treatment of cancer in China and Laos. Its medical benefits, however, are still lacking of scientific evidence. Two extracts successively obtained from the root of H. angustifolia L., namely the aqueous root extract (ARE) and the ethanolic root extract (ERE), were used to evaluate the antioxidant and anticancer activities in vitro, and the antitumor efficacy of ARE was examined in vivo, respectively. MATERIALS AND METHODS: ARE and ERE were extracted successively from H. angustifolia L. root with water and ethanol. In vitro antioxidant activities were assessed by radicals scavenging assay, ferrous chelating assay and reducing power assay. In vitro anticancer activities of ARE and ERE were evaluated by their cytotoxic effects against three human cancer cell lines. In addition, the anti-tumor activities of ARE in vivo were assessed by using Ht1080 (human fibrosarcoma cell line Ht1080) tumor xenografts mice. BALB/c nude mice were orally administrated with 200mg/kg/d of ARE. The tumor inhibition rate was determined on day 42 after treatment by using histopathology analysis of the tumor tissues. Furthermore, relevant biochemical parameters in blood were analyzed to monitor their cytotoxic effect. RESULTS: In vitro assays indicated that ARE possessed relatively higher antioxidant and anticancer activities than ERE, with IC50 values of 82.31 ± 9.62, 62.50 ± 6.99, and 127.49 ± 2.9 µg/mL against DLD-1, A549, and HepG2 cells, respectively. In vivo tumor inhibition experiments suggested that ARE possessed significant antitumor efficacy in BALB/c nude mice with a tumor inhibition rate of 49.83 ± 14.38% (p<0.05) and little toxicity was observed to the host. CONCLUSION: ARE from H. angustifolia L. possessed high antioxidant activities is active against liver cancer HepG2, lung cancer A549 and colon cancer DLD-1 cells in vitro and tumor xenografts bearing BALB/c nude mice in vivo. Further studies on elucidation of the mechanisms involved and isolation of the active components may provide more valuable information for the development of functional products from H. angustifolia L. and their application in cancer treatment.