Plant-Derived Compounds Targeting Pancreatic Beta Cells for the Treatment of Diabetes

Mechanistic In vitro Evaluation of Prosopis farcta Roots Potential as an Antidiabetic Folk Medicinal Plant

OBJECTIVE

Prosopis farcta has been used as a traditional herbal medicine for treating Diabetes mellitus. The aim of this study is to investigate the antidiabetic mechanisms of infusion (INF) extract of P. farcta and discovering the active extract for the first time.

MATERIALS AND METHODS

Six different extracts of P. farcta were prepared using five different solvents (ethanol, n-hexane, acetone, ethanol:water (1:1 v/v), and water). Cytotoxicity and cell proliferation assays were performed on mouse pancreatic β-cells (β-TC3) using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium method. The effects of P. farcta on glucose metabolism (in a hepatocellular carcinoma cell line [HepG2]) and glucose diffusion across a dialysis membrane (as a model of cellular glucose absorption) were evaluated. The protective effect of various P. farcta extracts on cytotoxicity, mitochondrial membrane potential (MMP), and streptozotocin (STZ)-induced apoptosis in β-TC3 cells was investigated.

RESULTS

Cytotoxicity study indicated that extracts were safe on β-TC3 and HepG2 (≤0.5 mg/ml). INF protected β-TC3 cells from apoptosis induced by STZ and improved cell viability for 20% and significantly decrease depolarization of MMP (P < 0.005). The results showed that INF inhabited breaking/streaking the DNA. Proliferation study showed no significant increase in the number of cells either at single or multiple doses. In moderate hyperglycemia (11.1 mmol/l), a significant glucose-lowering effect was observed but glucose diffusion was not the probable mechanism of extracts antidiabetic effect. In conclusion, only INF, the traditionally used extract, has an antidiabetic potential by attenuating the death and apoptosis induced by STZ in β-TC3 cells and increase glucose consumption.

CONCLUSION

The present study demonstrates that only INF extract have an antidiabetic potential by attenuating the death and apoptosis induced by STZ in β-TC3 cells and increase glucose consumption.

SUMMARY

Six different extracts from P. farcta were prepared using five different solvents [ethanol, n-hexane, acetone, ethanol: water (1:1 v/v), and water]The protective effect of various P. farcta extracts on cytotoxicity, mitochondrial membrane potential (MMP), and Streptozotocin-induced apoptosis in β-TC3 cells were investigated.Infusion has an antidiabetic potential by attenuating the death and apoptosis induced by STZ in β-TC3 cells and increase glucose consumptionThe effect of infusion extract on glucose consumption in hepatocellular carcinoma cell line cells (a) and effect of infusion extract on glucose consumption in hepatocellular carcinoma cell line cells adjusted by optical density MTT (b). Significance was calculated by analysis of variance (*P ≤ 0.05). MTT: 3 (4,5 dimethylthiazol 2 yl) 2,5 diphenyltetrazolium. Abbreviations used: AC: Acetone extract; ANOVA: Analysis of variance; BSA: Bovine serum albumin; β-TC3: Mouse pancreatic β-cells; DMEM: Dulbecco modified Eagle medium; DMSO: Dimethyl sulfoxide; ETH: Ethyl acetate extract; FBS: Fetal bovine serum; HDETH: Hydroethanolic extract; HepG2: Hepatocellular carcinoma cell line; HEX: Hexane extract; INF: Infusion; KUMS: Kermanshah University of Medical Sciences; MMP: Mitochondrial membrane potential; MTT: 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium; NaCl: Natrium chloride; OD: Optical density; spp: Species; STZ: Streptozotocin; Tag: T-antigen; USA: United States of America.

A Lanosteryl Triterpene from Protorhus longifolia Improves Glucose Tolerance and Pancreatic Beta Cell Ultrastructure in Type 2 Diabetic Rats

Type 2 diabetes remains one of the leading causes of death worldwide. Persistent hyperglycemia within a diabetic state is implicated in the generation of oxidative stress and aggravated inflammation that is responsible for accelerated modification of pancreatic beta cell structure. Here we investigated whether a lanosteryl triterpene, methyl-3β-hydroxylanosta-9,24-dien-21-oate (RA-3), isolated from Protorhus longifolia can improve glucose tolerance and pancreatic beta cell ultrastructure by reducing oxidative stress and inflammation in high fat diet and streptozotocin-induced type 2 diabetes in rats. In addition to impaired glucose tolerance, the untreated diabetic rats showed increased fasting plasma glucose and C-peptide levels. These untreated diabetic rats further demonstrated raised cholesterol, interleukin-6 (IL-6), and lipid peroxidation levels as well as a destroyed beta cell ultrastructure. Treatment with RA-3 was as effective as metformin in improving glucose tolerance and antioxidant effect in the diabetic rats. Interestingly, RA-3 displayed a slightly more enhanced effect than metformin in reducing elevated IL-6 levels and in improving beta cell ultrastructure. Although the involved molecular mechanisms remain to be established, RA-3 demonstrates a strong potential to improve pancreatic beta cell ultrastructure by attenuating impaired glucose tolerance, reducing oxidative stress and inflammation.

Changes in pancreatic histology, insulin secretion and oxidative status in diabetic rats following treatment with Ficus deltoidea and vitexin

BACKGROUND

The potential application of Ficus deltoidea and vitexin for the management of symptomatologies associated with diabetes mellitus (DM) has gained much attention. However, less firm evidence comes from data to augment our understanding of the role of F. deltoidea and vitexin in protecting pancreatic β-cells. The aim of this study was to assess histological and oxidative stress changes in the pancreas of streptozotocin (STZ)-induced diabetic rats following F. deltoidea extract and vitexin treatment.

METHODS

F. deltoidea and vitexin was administrated orally to six-weeks STZ-induced diabetic rats over 8 weeks period. The glucose and insulin tolerances were assessed by intraperitoneal glucose (2 g/kg) tolerance test (IPGTT) and intraperitoneal insulin (0.65 U/kg) tolerance test (IPITT), respectively. Subsequently, insulin resistance was assessed by homeostasis assessment model of insulin resistance (HOMA-IR), quantitative insulin sensitivity check index (QUICKI) and the insulin/triglyceride-derived McAuley index. The histological changes in the pancreas were then observed by hematoxylin-eosin (H&E) staining. Further, the pattern of fatty acid composition and infrared (IR) spectra of the serum and pancreas were monitored by gas chromatography (GC) method and Fourier Transform Infrared (FT-IR) spectroscopy.

RESULTS

F. deltoidea and vitexin increased pancreatic antioxidant enzymes and promoted islet regeneration. However, a significant increase in insulin secretion was observed only in rats treated with F. deltoidea. More importantly, reduction of fasting blood glucose is consistent with reduced FT-IR peaks at 1200-1000 cm^-1.

CONCLUSIONS

These results accentuate that F. deltoidea and vitexin could be a potential agent to attenuate pancreatic oxidative damage and advocate their therapeutic potential for treating DM.