BackgroundThe leaves of Strobilanthes crispus (S. crispus) which is native to the regions of Madagascar to the Malay Archipelago, are used in folk medicine for their antidiabetic, diuretic, anticancer and blood pressure lowering properties. Crude extracts of this plant have been found to be cytotoxic to human cancer cell lines and protective against chemically-induced hepatocarcinogenesis in rats. In this study, the cytotoxicity of various sub-fractions of dichloromethane extract isolated from the leaves of S. crispus was determined and the anticancer activity of one of the bioactive sub-fractions, SC/D-F9, was further analysed in breast and prostate cancer cell lines.MethodsThe dichloromethane extract of S. crispus was chromatographed on silica gel by flash column chromatography. The ability of the various sub-fractions obtained to induce cell death of MCF-7, MDA-MB-231, PC-3 and DU-145 cell lines was determined using the LDH assay. The dose-response effect and the EC50 values of the active sub-fraction, SC/D-F9, were determined. Apoptosis was detected using Annexin V antibody and propidium iodide staining and analysed by fluorescence microscopy and flow cytometry, while caspase 3/7 activity was detected using FLICA caspase inhibitor and analysed by fluorescence microscopy.ResultsSelected sub-fractions of the dichloromethane extract induced death of MCF-7, MDA-MB-231, PC-3 and DU-145 cells. The sub-fraction SC/D-F9, consistently killed breast and prostate cancer cell lines with low EC50 values but is non-cytotoxic to the normal breast epithelial cell line, MCF-10A. SC/D-F9 displayed relatively higher cytotoxicity compared to tamoxifen, paclitaxel, docetaxel and doxorubicin. Cell death induced by SC/D-F9 occurred via apoptosis with the involvement of caspase 3 and/or 7.ConclusionsA dichloromethane sub-fraction of S. crispus displayed potent anticancer activities in vitro that can be further exploited for the development of a potential therapeutic anticancer agent.

Endothelial cell dysfunction is considered to be one of the major causes of vascular complications in diabetes. Polyphenols are known as potent antioxidants that can contribute to the prevention of diabetes. Corn silk has been reported to contain polyphenols and has been used in folk medicine in China for the treatment of diabetes. The present study aims to investigate the potential protective role of the phenolic-rich fraction of corn silk (PRF) against injuries to vascular endothelial cells under high glucose conditions in vitro and in vivo. The protective effect of PRF from high glucose toxicity was investigated using human umbilical vein endothelial cells (HUVECs). The protective effect of PRF was subsequently evaluated by using in vivo methods in streptozotocin (STZ)-induced diabetic rats. Results showed that the PRF significantly reduced the cytotoxicity of glucose by restoring cell viability in a dose-dependent manner. PRF was also able to prevent the histological changes in the aorta of STZ-induced diabetic rats. Results suggested that PRF might have a beneficial effect on diabetic patients and may help to prevent the development and progression of diabetic complications such as diabetic nephropathy and atherosclerosis.

Diabetes Mellitus (DM) has become a significant public health problem worldwide and primarily correlated to hyperglycaemia and abnormal lipid and antioxidant levels. Fruit and vegetable wastes are rich in phenolic compounds thus suitable for antioxidant sources. Cornsilk (CS), a maize cultivar waste, also contains phenolic compounds. The current study investigated the anti-hyperglycemic and antioxidative properties of the Phenolic-Rich Fraction of Cornsilk (PRF-CS) in Streptozotocin (STZ)-induced diabetic rats. Five groups of 30 male Sprague Dawley rats were employed in this study. A sample size of six rats each is placed in five groups: Normal-Control (NC), Diabetic-Control (DC), Diabetic-PRF-CS treated 100 mg/kg (DPRF100) and 200 mg/kg (DPRF200), and Diabetic-Metformin Treated (Dmet) groups. The PRF-CS was administered at 100 and 200 mg/kg doses for 28 consecutive days to the diabetic rats. Treatment with both doses of PRF-CS (DPRF100 and DPRF200) significantly decreased the blood glucose levels of the rats (p<0.05). Additionally, the PRF-treated rats demonstrated significantly decreased (p<0.05) lipid peroxidation (3.60±0.23 and 3.31±0.56 µmol/g, respectively). The hepatic antioxidant enzyme activities of Superoxide Dismutase (SOD) (169.35±4.75 and 175.30±3.69 U/mg, respectively), Catalase (CAT) (1457.51±152.74 and 2011.99±396.96 U/mg), and Glutathione Peroxidase (GSH-Px) (63.43±2.99 and 78.47±4.51 U/mg) were also elevated in contrast to the DC group. Furthermore, the PRF-CS administration improved the histological alterations in the liver tissues of the DPRF100 and DPRF200 rats. In conclusion, PRF-CS treatment exhibited protective effects in the diabetic rat model by decreasing oxidative stress and preserving liver integrity.

Presently, there is growing interest to use agricultural wastes as by-products for further exploitation as food additives or supplements. The waste product which is typically thrown into the environment has been revealed to exhibit certain nutritional and pharmacological properties. Some functional compounds have been reported to exert significant nutritional and pharmacological properties such as antioxidant, anticancer, antidiabetic, antimicrobial, etc. Based on recent literature, many reports or studies focused on the utilization and pharmacological effects of some selected agro-industrial by-products. This trend could provide the theoretical basis for further rational development and utilization of the waste for the therapeutic and health purposes.