Anti-obesity potentials of aqueous and methanol extracts of <i>Vernonia amygdalina</i> Del. Leaves in high-fat diet fed rats

Abstract

Background: Obesity is currently a global epidemic. Conventional treatments have not been very satisfactory to patients, warranting a search for alternative therapeutic options that are natural, safe and affordable. This study therefore investigated the anti-obesity potentials of aqueous and methanol extracts of Vernonia amygdalina Del (AEVA and MEVA respectively) in a rat model in which obesity was induced using a high-fat diet. Materials and Methods: Forty two Wistar rats were randomised into 7 groups of 6 rats each. One group served as the Normal Control group and obesity was induced in the other 6 groups. One of the 6 groups each served as Positive Control and Negative Control while the 4 test groups were designated AEVA100, AEVA500, MEVA50 and MEVA200, respectively. The study lasted for 12 weeks after which standard protocols were followed for all analyses and determinations. Results: The results show that both AEVA and MEVA at the tested concentrations resulted in significant (P < 0.05) weight loss (without affecting internal organs negatively), and significant (P < 0.05) improvement in some metabolic markers of obesity in the test rats compared to the negative control rats. MEVA 200 had the greatest anti-obesity effect while MEVA 50 was the least effective. All the test extracts compared well with Orlistat used as the positive control drug on all counts. Conclusion: The observed weight-loss benefits of AEVA and MEVA are attributable to the rich milieu of phytochemicals found in Vernonia amygdalina Del. Further studies to unlock the mechanisms through which the observed weight loss is mediated are warranted.

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

“…Thus, Vernonia amygdalina incorporation into diets could inhibit body fat accumulation by reducing cholesterol build-up in the rats. The results and interpretations agree with that of previous findings by Egedigwe et al (2016a), Akah and Okafor (1992a;1992b), Adaramoye et al (2008), Egedigwe and Ijeh (2010a), Atangwho et al (2012), Ijeh et al (2014). Several researchers have also reported the hypolipdaemic effects of saponins from Parkia biglbosa leaves (Zhao et al, 2008) and Platycodin grandiflorum (Komolafe et al, 2013).…”

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

“…The very high concentrations of leptin found in the NeC are likely due to increased production of the hormone in response to a reduced sensitivity to leptin as mentioned earlier. The extracts may have restored leptin sensitivity to the test rats; a fall-out of which would be the reduced feed intake in the test groups reported earlier (Egedigwe et al 2016).…”

“…The weight loss reported in rats given extracts of VA is believed to be due to the rich milieu of phytochemicals present in the leaves of the plant (Egedigwe et al 2016). Such phytochemicals include (but are not limited to) saponins, sesquiterpenes, lactones and flavonoids (Ijeh & Ejike 2011).…”

“…The materials used for this study and the study design were published recently (Egedigwe et al 2016) and will, therefore, be described only briefly here.…”

“…Recently, our group reported that aqueous and methanol extracts of Vernonia amygdalina Del. (Asteraceae), a popularly consumed dark green leafy vegetable in Nigeria, was effective in causing significant weight loss (while sparing vital organs) and normalizing metabolic markers of obesity in a murine model fed a high-fat diet (HFD) (Egedigwe et al 2016). Subsequent to that report, the possible mechanism(s) of action of the extracts were investigated.…”