BackgroundThe rhizome of Hydnophytum formicarum Jack., a medicinal plant known in Thai as Hua-Roi-Roo, has been used in Thai traditional herbal medicine for treatment of cancer. We assessed the ability of its ethanolic and phenolic-rich extracts and its major phenolic compound, sinapinic acid, possessing histone deacetylase (HDAC) inhibitory activity to inhibit proliferation of 5 human cancer cell lines.MethodsHeLa cells were used to study HDAC inhibitory activity of the extracts, sinapinic acid, and a well-known HDAC inhibitor sodium butyrate. Five human cancer cell lines and one non-cancer cell line were used to study antiproliferative activities of the plant extracts, sinapinic acid and sodium butyrate, comparatively.ResultsResults indicated that ethanolic and phenolic-rich extracts of H. formicarum Jack. rhizome possessed both antiproliferative activity and HDAC inhibitory activity in HeLa cells. Sinapinic acid, despite its lower HDAC inhibitory activity than the well-known HDAC inhibitor sodium butyrate, inhibited the growth of HeLa and HT29 cells more effectively than sodium butyrate. However, sinapinic acid inhibited the growth of HCT116 and Jurkat cells less effectively than sodium butyrate. The non-cancer cell line (Vero cells) and breast cancer cell line (MCF-7 cells) appeared to be resistant to both sinapinic acid and sodium butyrate. The growth inhibitory effects of the ethanolic and phenolic-rich extracts and sinapinic acid in HeLa cells were mediated by induction of apoptosis.ConclusionsThe results of this study support the efficacy of H. formicarum Jack. rhizome ethanolic and phenolic-rich extracts for the treatment of cervical cancer, colon cancer, and T- cell leukemia in an alternative medicine. Further studies of other active ingredients from this plant are needed.

A number of Houttuynia cordata fermentation products are commercially available in Thailand. However, their anticancer activity remains to be investigated. In this study, the phenolic acid composition and anticancer activity of two commercialized H. cordata fermentation products were investigated. Reversed phase HPLC was used to identify and quantify phenolic acids. MTT and Annexin V staining assays were used to investigate antiproliferative and apoptosis induction activities, respectively. Seven phenolic acids including protocatechuic, p-hydroxybenzoic, vanillic, syringic, p-coumaric, ferulic, and sinapinic acids were detected in the water-soluble constituents of both fermentation products 1 and 2. Water-soluble constituents of fermentation product 2 containing a greater phenolic acid content were more effective than product 1 in inhibiting the growth of HeLa, HCT116, and HT29 cells in a dose-and time-dependent manner. The non-cancer cell line Vero cells appeared to be resistant to both fermentation products. The growth inhibitory effects of both fermentation products in HeLa, HCT116, and HT29 cells included induction of apoptosis. These results suggest that commercially available fermentation products of H. cordata contain several anticancer phenolic acids that may be beneficial in the treatment of human cancer.