Antiangiogenesis and antioxidant activity of ethanol extracts of Pithecellobium jiringa.

BACKGROUND: Angiogenesis plays a critical role in embryonic development and various physiological processes. However, excessive angiogenesis is associated with several pathological conditions including cancer. Pithecellobium jiringa (Jack) Prain is a traditional medicinal plant from the family Leguminosae. It is native to the Southeast Asia, where it has been used traditionally for treatment of various ailments such as hypertension and diabetes. The present work is aimed to study antioxidant and antiangiogenesis activities of P. jiringa ethanol extracts. METHODS: P. jiringa fruit rinds were extracted with ethanol and 50% ethanol. The antioxidant property was analysed using, 1,1-diphenyl-2-picryl-hydrazyl free radical scavenging assay. Phytochemical analysis was performed using thin layer chromatography and colorimetric methods. Then, cell growth inhibition was studied against a panel of human cell lines by MTT test. In vitro inhibition of angiogenesis was studied by the following assays: isolated rat aortic rings cell viability, colony formation, endothelial cell migration, endothelial tube formation on matrigel, and expression of vascular endothelial growth factor by endothelial cells. In vivo antiangiogenesis effect was studied by utilising fertilised chick embryos assay. The results were statistically analysed by analysis of variance. RESULTS: Ethanolic and 50% hydro-ethanolic extracts showed relatively high concentration of total phenolics associated with potent antioxidant activity. The rat aortic rings study conducted showed potent inhibition of the microvessels outgrowth with IC50s 5.27 ± 0.81 µg/ml (ethanolic) and 4.45 ± 0.63 µg/ml (50% hydro-ethanolic). Both extracts arrested the growth of human endothelial cells via down-regulation of VEGF expression, leading to inhibition of other angiogenesis cascades including migration of endothelial cells, and formation of capillary network on matrigel matrix. The extracts also inhibited the neovascularisation of chick embryo chorioallantoic membrane. CONCLUSIONS: P. jiringa extracts inhibit angiogenesis by blocking the VEGF expression thus inhibiting endothelial cells proliferation, migration and differentiation most likely due to presence of the antioxidant phenolics.

Koetjapic acid, a natural triterpenoid, induces apoptosis in colon cancer cells.

Deregulated cell signaling pathways result in cancer development. More than one signal transduction pathway is involved in colorectal cancer pathogenesis and progression. Koetjapic acid (KA) is a naturally occurring seco-A-ring oleanene triterpene isolated from the Sandoricum koetjape stem bark. We report the cellular and molecular mechanisms of anticancer activity of KA towards human colorectal cancer. The results showed that KA induces apoptosis in HCT 116 colorectal carcinoma cells by inducing the activation of extrinsic and intrinsic caspases. We confirmed that KA-induced apoptosis was mediated by DNA fragmentation, nuclear condensation and disruption in the mitochondrial membrane potential. Further studies on the effect of KA on cancer pathways show that the compound causes down-regulation of Wnt, HIF-1α, MAP/ERK/JNK and Myc/Max signaling pathways and up-regulates the NF-κB signaling pathway. The result of this study highlights the anticancer potential of KA against colorectal cancer.