Cytotoxic Effect and Insulin-Like Characteristic of Peganum harmala: An in vitro Study

 Peganum harmala has emerged as a promising anti-diabetic medicine. There is no study regarding the impact of P. harmala concentration on the insulin secretion, C-peptide secretion, and glucose uptake. We investigated the effect of different concentrations of methanolic extracts of P. harmala seed and leaf on insulin and C-peptide secretion, and glucose uptake.

 After the cell passaging, pancreatic carcinoma cell line (PANC-1) and HT1080 were treated with different concentrations of seed and leaf extract of P. harmala, harmine, and ghrelin agonists. The MTT was employed to assess the cell survival at the selective doses, and using a spectrophotometer, the absorbance was determined at 570 nm. After 72-h treatment, the insulin and C-peptide secretion were measured by ELISA. To measure the intracellular glucose concentrations after treating muscle carcinoma cell lines, glucose oxidase method was utilized.

 P. harmala seed and leaf extracts increased the secretion of insulin and C-peptide in a dose-dependent manner compared to ghrelin and harmine. These extracts increased the intracellular glucose concentration at high doses (150 and 1500 µg/ml for the seed and leaf extract, respectively) of HT1080 cell line. However, their high concentration was toxic and reduced the cell survival. The methanolic extracts of seed showed a higher insulin (17.5-fold) and C-peptide (7.8-fold) secretion compared to the leaf methanolic extracts.

 Due to the presence of β-carbolines, the P. harmala seed extract has toxicity and affects insulin secretion and C-peptide uptake secretion at lower concentrations than those of leaf extract.