Diabetes mellitus is a chronic metabolic disease and predicted to increase about 366 million cases globally by end of 2030. Type 2 Diabetes is characterized by abnormal insulin secretion followed by inability of beta cells to compensate for insulin resistance. Most individuals diagnosed with diabetes are found to be obese and obesity as well is one of the major risk factors contributing to diabetes. Although modern medicine is used to control blood glucose level in diabetic patients but there is demand for natural products as anti-diabetic agents due to the side effects seen in the current drugs. In this study, we explore Nephelium lappaceum.L’s (or locally known as rambutan rind) ability as an anti-hyperglycemic agent in a type 2 diabetic animal model. The rind of N. lappaceum is found to consist of high antioxidant activity and possess in-vitro anti-hyperglycemic activity. This study is aimed initially to prepare standardised ethanolic extracts of N. lappaceum rind, evaluate toxicity effects in rat model, develop obesity induced type 2 diabetes rat model and finally investigate the anti-glycemic effects of Nephelium lappaceum rind in the diabetic rat model. Ethanolic extraction was followed as previously described to obtain N. lappaceum rind extract. Geraniin being the major bioactive compound in N. lappaceum rind was detected in LC/MS and quantified using HPLC chromatogram method to ensure a standardised sample was prepared. Biological standardisation was also carried out by subjecting the N. lappaceum rind to both alpha glucosidase and alpha amylase assay’s and to establish its in-vitro anti-hyperglycemic activity. Toxicity studies of N. lappaceum rind were carried out in Sprague dawley rats. In the acute toxicity study, rats were given 50mg, 200mg, 1000mg and 2000mg/kg of N.lappaceum rind orally for 14 days whereas in the sub-chronic toxicity study the rats were given a low and high concentration of N. lappaceum rind for 28days (500mg and 2000mg/kg). Type 2 diabetes was seen to develop in the rat model by feeding them with a high fat diet for 12 weeks and injected with 55mg/kg streptozotocin and 210mg/kg nicotinamide. Then, the diabetes induced rats were treated with N. lappaceum rind at 500mg and 2000mg concentrations for 28 days. Positive control rats were treated with 200mg metformin. In this study, we obtained a 41.06% yield of ethanolic extracts from powdered N. lappaceum rind, while geraniin present in the extract was quantified at 33.0 ± 0.2 mg geraniin/g extract. N. lappaceum rind did not show any toxic effect in the rats both during acute and sub-chronic toxicity study. All biochemical analysis, histology of organs, body weight and relative organ weight clearly showed that there were no significant changes in treated rats. Our study also revealed that, the diabetes induced rats treated with 2000mg N. lappaceum showed reduction in blood glucose level and improved insulin levels which were similar to metformin treated group. Pancreas histology revealed that, the group treated with 2000mg of N. lappaceum had a good distribution of healthy islets and the treatment is comparable to the effect of metformin-treated group. Immunohistochemical staining with Glut-4 and PPAR-gamma antibody also markers for regeneration was over expressed in N. lappaceum treated group with large regenerating islets and the effects were similar to metformin-treated group. In conclusion, N. lappaceum rind extract was able to display anti-hyperglycemic activity at a dose of 2000mg/kg without any toxic effects in high fat diabetes-induced rats.

Immune system plays pivotal role against cancer progression. However, in the event of cancer development, tumour cells trigger immunosuppressive environment via the myeloid-derived suppressor cells and the T-regulatory (Treg) cells. The Treg T cells are a subset of CD4+ T lymphocytes, which have crucial roles in regulating immune homeostasis and promoting the establishment and maintenance of peripheral tolerance. Studies have reported palm oil as rich source of tocotrienol that able to exhibit anti-tumour and immunomodulatory properties in mouse breast cancer model. However, the most potent isomer of tocotrienol namely gamma-tocotrienol (γT3) modulating host immune system of mouse breast cancer model has not yet been elucidated. Hence, this study was targeted to investigate T-helper and T-regulatory cell population and mechanism involved upon supplementation of γT3. The in vivo study consists of treatment and prevention model. In treatment model, female BALB/c mice were induced with breast cancer and once a tumour was palpable, fed with either soy oil (vehicle) or gamma-tocotrienol (γT3) up to 35 days. In prevention model, female BALB/c mice were fed with either soy oil (vehicle) or gamma-tocotrienol (γT3) for two weeks. Then two groups were inoculated with tumour cells and remaining two groups were not inoculated with tumour cells. All the mice continued to receive the same supplementation until day 49. Every seven days six mice from each group were culled. The peripheral blood was used for flowcytometry analysis, organs collected for histology, tumour collected for immunohistochemistry, and spleen culture for CD4+ T-cell isolation and gene expression study. Although treatment model showed reduction in tumour volume and weight other immunological results were not promising. The prevention model results showed reduction in tumour volume and weight in γT3 fed mice. Interestingly, γT3 increased necrosis in tumour tissue and prevents metastasis in lung and liver of tissue sections. Flow cytometry analysis revealed T-helper cell population (CD4+, CD8+ and NK cell) were increased and T-regulatory cells were suppressed in γT3 treated mice. Increased level of IFN-γ and suppressed level of TGF-β cytokines were noted in γT3 mice. In addition, immunohistochemistry analysis showed strong expression of CD4+, moderate expression of IL-12Rβ2, IL-24 and weak expression of FoxP3 in the γT3 fed mice. Results from mouse T-helper array showed, γT3 regulated immune response pathway by expressing 10 genes namely IFN-γ, IL-2, IL-5, CCL5, CCL11, CCR4, RORA, RORC, IL-9 and FoxP3. Among this, IFN-γ, IL-2 and IL-17A were identified as robustly expressed genes by γT3. In conclusion, γT3 showed anti-tumour and immune modulatory activities by increasing T-helper population in immunocompetent mice via immune response pathway. Therefore, γT3 supplementation showed good prognosis in breast cancer induced mouse and can be considered as an immunotherapeutic agent for the treatment of breast cancer.