DOI: 10.14457/tu.the.2015.646
title: The effect of Benjakul water extract on pancreas in rats fed a high-fat diet

description: Benjakul is a name of the medicinal formula widely used in Thai traditional medicine. The formula is composed of five species of medicinal plants, Piper sarmentosum Roxb. (wild betal leaf bush), Piper retrofractum Vahl. (long pepper), Piper interruptum Opiz. (Pepper wood), Plumbago indica Linn. (rose-color lead wood) and Zingiber mekongense Gagnep. (ginger). Decoction of Benjakul has been used as a kind of adaptogenic agent. The certain formula of Benjakul has been prescribed to reduce hyperglycemia. Since one of the symptoms found in metabolic syndrome is the prediabetes state defined as mild hyperglycemia and glucose intolerance, it is interesting to study the effect of Benjakul on this situation in metabolic syndrome. The study extends its intention, furthermore, to evaluate its effect on the other relating biochemical disturbance and pathological signs of tissue, especially pancreas. The study was done in Sprague Dawley rats fed with a high fat diet. The investigation includes the determination of blood parameters associated with the syndrome, organ weight and the effect on the specific organ, pancreas. The later includes the effect of Benjakul on insulin secreting function in relating to blood parameters and some pathological effects of the pancreas. Decoction of Benjakul was freeze-dried. High-fat fed rats were gavaged with 41.3 mg/kg rat weight (HFB1) or 413 mg/kg rat weight (HFB10). The study was compared to rats fed with high-fat alone (HF) and the control, fed with standard chow. The effect of the whole plant of Piper sarmentosum Roxb., a single herb remedy, was studied in comparison to the formula as Benjakul. Metformin was used as a positive control since it was usually prescribed in metabolic syndrome. The results showed abdominal and epididymal fat weights, adipocyte size, and total cholesterol and low-density lipoprotein-cholesterol (LDL-C) levels were decreased, whereas serum high-density lipoprotein-cholesterol (HDL-C) levels were increased in the short-term HFB1 group in comparison with the HF group. Short-term HFB10 group showed a significant decrease in abdominal fat weight, adipocyte size and serum triglyceride levels when compared with the HF group. The same trends were observed in HFW and HFM groups. Although there were no significant differences in total cholesterol, LDL-C and HDL-C levels between the control and HFB10 groups. Consistently, intermediate-term treatment with low dose of BWE reduced abdominal fat weight and adipocyte size. For the effects of BWE on glucose homeostasis parameter, all short-term treatments had no effect on the FBG and fasting serum insulin levels, in high-fat diet-fed rats. Unexpectedly, the intermediate-term HFB1 group had significantly increased AUC, whereas the HF group did not have any significant change compared with the control group. When focus on the effects of BWE on pancreatic abnormalities, in the short-term experiment, low and high dose BWE increased the expression of pancreatic insulin signaling gene, insulin receptor substrate-2 (IRS-2), but had no effect on glucose-sensing genes, glucose transporter-2 (GLUT-2) and glucokinase (GK). Short-term treatments with WWE and metformin significantly prevented the decrease of IRS-2 and GLUT-2 mRNA levels in high-fat diet-fed rats. In contrast to the short-term study, intermediate-term treatment with BWE suppressed the expression of pancreatic IRS-2, GLUT-2 and GK mRNA. Notably, histological study of pancreas from all treatment groups showed a reduction of vacuoles formation in pancreatic acinar cells but had no effect on pancreatic senescence. In addition, only the intermediate-term HFB1 group showed a significant decrease in the pancreatic nuclear factor-kappa B p65 (NF-κB p65) mRNA levels. In conclusion, the results suggested that BWE has a protective effect against pancreatic abnormalities in rats fed-high fat diet. The mechanisms may be related to up-regulation of insulin signaling gene and inhibition of vacuole accumulation in the pancreas. It is compatible with the compensation mechanism of pancreas in early stage of diabetes, same as the compensation mechanism in metabolic syndrome. Since intermediate-term treatment of BWE may not appropriate. Therefore, BWE may appropriate for short-term used, same as metformin in metabolic syndrome treatment. Further pharmacological evaluations are required to identify and isolate the active compounds in BWE for elucidating their mechanisms of active on lipid metabolism.