Anti-obesity effect of argel (Solenostemma argel) on obese rats fed a high fat diet

Abstract

Ethnopharmacological relevance: Solenostemma argel (Argel) is a desert plant commonly used in Egyptian and Sudanese traditional medicine to suppress appetite, for treatment of diabetes, and as an antispasmodic and anti-inflammatory agent. Previously the anti-diabetic, hypolipidemic and lipase inhibitory activities of Argel were reported in animal studies and in-vitro assays. However, its specific mechanism of action as an anti-obesity agent has not been studied before.

Aim of the study: Assessment of the possible anti-obesity effect of Solenostemma argel on diet-induced obesity and elucidation of its mechanism of action, as well as, standardization of the active plant extract.

Materials and methods: The ethanolic extract (EtOH-E) and its fractions (CH₂Cl₂-F: methylene chloride and BuOH-F: n-butanol) were prepared from the aerial parts of S. argel and studied at two dose levels; 200 and 400 mg kg^-1 in a model of high fat diet (HFD) fed rats. The animals (72 Male Wister rats) were assigned into 9 groups: group (i) fed with normal diet and groups (ii-iv) fed with high fat diet (HFD) for 16 weeks and treated with orlistat, EtOH-E, CH₂Cl₂-F and BuOH-F in the beginning of the 8th week. At the end of the experiment, blood samples were analysed for lipid and liver biomarkers, glucose and insulin levels, as well as, adipokines and inflammatory markers. Liver and adipose tissues were examined histopathologically and their homogenates were used to determine levels of oxidative stress markers and lipogenesis-related genes. Body weight was monitored weekly during the experiment.

Results: Our data showed that consumption of S. argel significantly controlled weight gain, attenuated liver steatosis, improved the lipid profile, modulated adipokines activities, increased β-oxidation gene expression, as well as, decreased the expression of lipogenesis-related genes and ameliorated inflammatory and lipid peroxidation derangement. The ethanolic extract was also standardized using LC-MS analysis for its content of stemmoside C.

Conclusions: The current study revealed that S. argel is a promising Egyptian natural drug, rich in pregnane glycosides, and could be considered a new therapeutic candidate targeting obesity.

Keywords: Adipokines; Body weight gain control; Diet-induced obesity; Lipolysis; Solenostemma argel; Stemmoside C.