Beneficial Effect of Thymelaea hirsuta on Pancreatic Islet Degeneration, Renal Fibrosis, and Liver Damages as Demonstrated in Streptozotocin-Induced Diabetic Rat

Objective. In Morocco, Thymelaea hirsuta (T. hirsuta) (Thymelaeacea) is a medicinal plant widely used to treat and prevent diabetes. The present study aimed to evaluate the medium-term antidiabetic effect of aqueous extract (AqTh) and ethyl acetate fraction (EaTh) of Th and to investigate their putative protective effect on pancreatic islet degeneration, diabetic nephropathy, and liver damages in streptozotocin (STZ)-diabetic rats. Methods. Experimental diabetes in rats was induced by a single intraperitoneal injection of 50 mg/kg of STZ. During the treatment period (4 weeks), 200 mg/kg AqTh and 50 mg/kg EaTh were orally administrated daily to STZ-diabetic rats. A group of parameters including fasting blood glucose, biochemical parameters, and intestinal α-glucosidase inhibition were studied. Furthermore, histological study of the pancreas, kidney, liver, and aorta was also realized. Results. At the end of the treatment, both AqTh and EaTh had normalized fasting blood glucose to 1.08 and 1.25 g/l, respectively. AqTh has also reduced urinary creatinine and HbAc1. The EaTh showed inhibitory activity against intestinal α-glucosidase, whereas AqTh did not have this inhibitory effect. Furthermore, pancreas hematoxylin and eosin staining showed that AqTh or EaTh prevents pancreatic islet cell degeneration. As the same kidney, Masson’s trichrome staining has shown a significant prevention of renal fibrosis in AqTh- or EaTh-treated diabetic rats. On the other hand, liver hematoxylin and eosin staining showed that AqTh and EaTh prevent liver damage. Conclusion. We conclude that medium-term administration of AqTh and EaTh exerts significant antihyperglycemic effect in STZ-diabetic rats possibly through intestinal α-glucosidase inhibition and protection against pancreatic islet cell damage. Moreover, AqTh and EaTh treatment prevent nephropathy and liver complications in STZ-diabetic rats

Inhibition of α-Glucosidase, Intestinal Glucose Absorption, and Antidiabetic Properties by Caralluma europaea

Many medicinal plants around the world are used for therapeutic purposes against several diseases, including diabetes mellitus. Due to their composition of natural substances that are effective and do not represent side effects for users, unlike synthetic drugs, in this study, we investigated the inhibitory effect of Caralluma europaea (CE) on α-glucosidase activity in vitro; then the kinetics of the enzyme were studied with increasing concentrations of sucrose in order to determine the inhibition type of the enzyme. In addition, this effect of Caralluma europaea (CE) was confirmed in vivo using rats as an experimental animal model. Among the five fractions of CE, only the ethyl acetate fraction of C. europaea (EACe) induced a significant inhibition of α-glucosidase and its inhibition mode was competitive. The in vivo studies were conducted on mice and rats using glucose and sucrose as a substrate, respectively, to determine the oral glucose tolerance test (OGTT). The results obtained showed that the EACe and the aqueous extract of C. europaea (AECe) have significantly reduced the postprandial hyperglycemia after sucrose and glucose loading in normal and diabetic rats. AECe, also, significantly decreased intestinal glucose absorption, in situ. The results obtained showed that Caralluma europaea has a significant antihyperglycemic activity, which could be due to the inhibition of α-glucosidase activity and enteric absorption of glucose

In Vitro Antioxidant Properties, Glucose-Diffusion Effects, α-Amylase Inhibitory Activity, and Antidiabetogenic Effects of <i>C. Europaea</i> Extracts in Experimental Animals

Caralluma europaea (Guss.) N.E.Br. (C. europaea), is a medicinal plant used traditionally to treat diabetes mellitus (DM) in Morocco. This study aimed to investigate the in vitro antioxidant properties, glucose diffusion effects, α-amylase inhibitory activity, and pancreatic protective effects of C. europaea in experimental alloxan-induced diabetes in mice. Total phenolic contents were determined by Folin–Ciocalteu colorimetric method, total flavonoid contents were measured by aluminum chloride colorimetric assay, and tannins contents were determined by employing the vanillin method. C. europaea ethyl acetate fraction exhibited high antioxidant potential in terms of radical scavenging (DPPH) (IC50 = 0.22 ± 0.01 mg/mL), β-carotene bleaching activity (IC50 = 1.153 ± 0.07 mg/mL), and Ferric-reducing antioxidant power. Glucose diffusion was significantly inhibited by the ethyl acetate fraction at 60,120and 180 min, while the aqueous extract did not have this inhibitory effect when compared with the control group. Potent α-amylase inhibitory activity was observed in the ethyl acetate fraction and the aqueous extract in vitro and in vivo using STZ-diabetic rats. On the other hand, the administration of the ethyl acetate fraction (60 mg/kg) significantly attenuated alloxan-induced death and hyperglycemia in treated mice. Furthermore, histopathological investigations revealed that the ethyl acetate fraction protected islets of Langerhans against alloxan-induced tissue alterations. These results suggest that C. europaea exhibited an important antihyperglycemic effect via the inhibition of glucose diffusion and pancreatic α-amylase activity. In addition, the antidiabetogenic effect of C. europaea might be attributed to their polyphenol and flavonoid compounds, which could be reacted alone, or in synergy, to scavenge the free radicals produced by the alloxan