Inhibition of Tumor Growth in Vitro by a Combination of Extracts from Rosa Roxburghii Tratt and Fagopyrum Cymosum

Objective: Traditional Chinese herbal medicines have a very long history. Rosa roxburghii Tratt and Fagopyrum cymosum are two examples of plants which are reputed to have benefits in improving immune responses, enhancing digestive ability and demonstrating anti-aging effects. Some evidence indicates that herbal medicine soups containing extracts from the two in combination have efficacy in treating malignant tumors. However, the underlying mechanisms are far from well understood. The present study was therefore undertaken to evaluate anticancer effects and explore molecular mechanisms in vitro. Methods: Proliferation and apoptosis were assessed with three carcinoma cell lines (human esophageal squamous carcinoma CaEs-17, human gastric carcinoma SGC-7901 and pulmonary carcinoma A549) by MTT assay and flow cytometry, respectively, after exposure to extract from Rosa roxburghii Tratt (CL) and extract from Fagopyrum cymosum (FR). $IC_{30}$ of CL and FR were obtained by MTT assay. Tumor cells were divided into four groups : control with no exposure to CL or FR; CL with $IC_{30}$ CL; FR with $IC_{30}$ FR; CL+FR group with 1/2 ($IC_{30}$ CL + $IC_{30}$ FR). RT-PCR and Western blot analysis were used to detect the expression of Ki-67, Bax and Bcl-2 at mRNA and protein levels. Results: Compared with the CL or FR groups, the combination of CL+FR showed significant inhibition of cell growth and increase in apoptosis; the mRNA and protein expression levels of Ki-67 and Bcl-2 in CL+FR group were all greatly decreased, while the expression of Bax was markedly increased. Conclusions: These results indicate that the synergistic antitumor effects of combination of CL and FR are related to inhibition of proliferation and induction of apoptosis.