BACKGROUND/OBJECTIVESYacon (Samallanthus sonchifolius), a common edible plant grown throughout the world, is well known for its antidiabetic properties. It is also known to have several other pharmacological properties including anti-inflammatory, anti-oxidant, anti-allergic, and anti-cancer effects. To date, the effect of yacon on gliomas has not been studied. In this study, we investigated the effects of yacon on the migration and proliferation of C6 glioma cells stimulated by fetal bovine serum (FBS).MATERIALS/METHODSCell growth and proliferation were determined by evaluating cell viability using an EZ-Cytox Cell Viability Assay Kit. FBS-induced migration of C6 glioma cells was evaluated by performing the scratch wound healing assay and the Boyden chamber assay. We also used western blot analysis to determine the expression levels of extracellular signal-regulated kinase 1/2 (ERK1/2), a major regulator of migration and proliferation of glioma cells. Matrix metallopeptidase (MMP) 9 and TIMP-1 levels were measured by performing reverse transcription PCR.RESULTSYacon (300 µg/mL) reduced both the FBS-induced proliferation of C6 glioma cells and the dose-dependent migration of the FBS-stimulated C6 cells. FBS-stimulated C6 glioma cells treated with yacon (200 and 300 µg/mL) showed reduced phosphorylation of ERK1/2 and inhibition of MMP 9 expression compared to those shown by the untreated FBS-stimulated C6 cells. In contrast, yacon (200 and 300 µg/mL) induced TIMP-1 expression.CONCLUSIONSOn the basis of these results, we suggest that yacon may exert an anti-cancer effect on FBS-stimulated C6 glioma cells by inhibiting their proliferation and migration. The most likely mechanism for this is down-regulation of ERK1/2 and MMP9 and up-regulation of TIMP-1 expression levels.

Yacon has been used in folk medicines as a medicinal tea for hypoglycemia treatment. In a recent study described herein, antioxidative, antibacterial, antifungal activities, and cell-protective functions of yacon leaves have been reported. To evaluate the effects on fibrosis on pancreatitis, the efficacy of 1% of yacon extract (YE) on dibutyltin dichloride (DBTC) (8 mg/kg)-induced pancreatitis in rats was examined. On the 21st day after the DBTC treatment, a large increase in collagen was observed in the pancreas in the DBTC-treatment group (DT). But this was noticeably decreased with YE. In relation to the expression of COX-2, there was no response or a very weak response in the pancreas of the control group (CON). However, in DT, strong expression of COX-2 was observed in the pancreas on the 14th day, and COX-2 was present in inflammatory cells in the pancreas of the DT, especially on the 21st day. The expression was decreased for YE compared with DT. A remarkable increase in TGF-β1 expression was observed in inflammatory cells in the pancreas in DT on the 21st day, whereas the expression was not found in YE after 21 days. However, on the 21th day, TGF-β1 expression was increased in acinar cells of YE compared with DT. VEGF expression was very similar to the expression of in the pancreas. These results suggest that YE has an inhibitory effect on DBTC-induced pancreatic fibrosis.