Aqueous and methanol extracts of Vernonia amygdalina leaves exert their anti-obesity effects through the modulation of appetite-regulatory hormones

Abstract

Context: Aqueous and methanol extracts of Vernonia amygdalina Del. (Asteraceae) (AEVA and MEVA, respectively) leaves are reported to possess anti-obesity properties, exerted through unknown mechanisms.Objective: This study investigated the effects of AEVA and MEVA on relevant hormones and enzymes in high-fat diet (HFD)-induced obese rats. Materials and methods: Forty-two Wistar rats were placed into seven groups. The test groups received 100 mg/kg.bw AEVA (AEVA100), 500 mg/kg.bw AEVA (AEVA500), 50 mg/kg.bw MEVA (MEVA50) and 200 mg/kg.bw MEVA (MEVA200), respectively. The positive control (PC) group received 20 mg/kg.bw Orlistat, while the negative control (NeC) and normal control (NoC) groups received distilled water. The extracts were given orally daily for 12 weeks. Thereafter, the concentrations/activities of relevant hormones/enzymes in their sera were determined. Results: Insulin concentrations (ng/ml) in the test groups ranged from 1.08 ± 0.01 (AEVA100) to 1.09 ± 0.01 (AEVA500). They were all similar (p > .05) to the NoC and PC controls. Leptin concentrations (pg/ml) in the test rats ranged from 0.02 ± 0.01 (AEVA500) to 0.03 ± 0.00 (MEVA50), and were all similar to the NoC group. The ghrelin concentrations of only the AEVA500 and MEVA200 groups were similar to those of the PC group (0.10 ± 0.01 pg/ml). AEVA100 and MEVA200 resulted in adiponectin concentrations (ng/ml) of the rats (0.27 ± 0.04 and 0.28 ± 0.04 respectively) that were similar to the PC group. The activities of lipoprotein lipase and the concentrations of intestinal amylase in the test rats were similar to values obtained for the control groups. Conclusion: Appetite regulation may be the mechanism through which the weight-loss properties of AEVA and MEVA are expressed. ARTICLE HISTORY

Modulatory effects of dietary supplementation by Vernonia amygdalina on high-fat-diet-induced obesity in Wistar rats

“…Therefore reduction in body weight is possible by means of a decrease in plasma leptin levels. These results are consistent with our previous report on extracts of Vernonia amygdalina restoring leptin sensi-tivity levels in rats (Egedigwe et al, 2016b). Similarly, there was a significant (p < 0.05) increase in insulin levels in HFD-fed rats relative to HFDVA, suggesting insulin resistance.…”

“…Therefore, a decrease in insulin levels in HFDVA could have reversed the high levels observed when animals were fed HFD. This is in agreement with our previous report, where extracts of Vernonia amygdalina reduced insulin levels, thereby restoring insulin sensitivity (Egedigwe et al, 2016b). Figure 1A shows the photomicrograph of the liver section in animals fed CDs, which appears normal with no inflammatory cells.…”

Obesity and Comorbidity: Could Simultaneous Targeting of esRAGE and sRAGE Be the Panacea?

“…(Priyanto et al, 2016; Richard et al, 2019). Furthermore, recent studies reported it to be one of the leading cause of deaths in the world with an annual mortality rate of 2.8–3.4 million (Egedigwe et al, 2016; Priyanto et al, 2016; Victoria et al, 2018).…”