Identification of terpenoids from Rubus corchorifolius L. f. leaves and their anti-proliferative effects on human cancer cells. Issue 3 (30th January 2017) - Chen, Xuexiang
Abstract : Two novel and four known terpenoids were isolated and identified from Rubus corchorifolius L. f. leaves. Two exhibited strong inhibitory effects on HCT116 human colon cancer cells, causing cell cycle arrest and apoptosis. Abstract : The leaves of Rubus corchorifolius L. f. have been consumed as a herbal tea for a long time. In this study, two novel (1 and5 ) and four known (2, 3, 4 and6 ) terpenoids were isolated from the leaves of Rubus corchorifolius L. f. Structural analysis was performed using various spectroscopic methods ( 1 H NMR, 13 C NMR and MS) to identify the following six compounds: (16α)-16, 17, 18-trihydroxy- ent -kauran-18- O -β-d -glucoside (1 ), ent -16β, 17-dialkyl-3-oxygen-kaurane (2 ), ent -kaurane-3α, 16β, 17-triol (3 ), ent -kaurane(5 R, 8 S, 9 R, 10 R, 13 R, 16 R )-2-one-16α, 17-diol (4 ), (16 R )-16β, 17, 19-trihydroxy- ent -kaur-3-one (5 ) and ent -16α, 17-dihydroxy-kauran-19-oic-acid (6 ). These compounds showed different inhibitory effects on various human cancer cells. Compounds3 and6 exhibited stronger inhibitory effects on human colon cancer HCT116 cells than the other 4 compounds. Flow cytometry analysis demonstrated that both compounds3 and6 caused cell cycle arrest at the G0/G1 phase and induced cellular apoptosis in HCT116 cells. Compounds3 and6 modulated the expression levels of key signaling proteins closely related to cell proliferation and apoptosis, i.e., increasing the levels of poly(ADP-ribose) polymerase, p53, and p27, and decreasing the levels of EGFR, cyclin D1, CDK2 and CDK4. Overall, our findings provided insight into the anticancer components of Rubus corchorifolius L. f. leaves, which could facilitate their utilization as functional food ingredients.