Effect of the herbal medicines in obesity and metabolic syndrome: A systematic review and meta‐analysis of clinical trials

Abstract

Obesity is a medical situation in which excess body fat has gathered because of imbalance between energy intake and energy expenditure. In spite of the fact that the variety of studies are available for obesity treatment and management, its “globesity” still remains a big challenge all over the world. The current systematic review and meta‐analysis aimed to evaluate the efficacy, safety, and mechanisms of effective herbal medicines in the management and treatment of obesity and metabolic syndrome in human. We systematically searched all relevant clinical trials via Web of Science, Scopus, PubMed, and the Cochrane database to assess the effects of raw or refined products derived from plants or parts of plants on obesity and metabolic syndrome in overweight and obesity adult subjects. All studies conducted by the end of May 2019 were considered in the systematic review. Data were extracted independently by two experts. The quality assessment was assessed using Consolidated Standards of Reporting Trials checklist. The main outcomes were anthropometric indices and metabolic syndrome components. Pooled effect of herbal medicines on obesity and metabolic syndrome were presented as standardized mean difference (SMD) and 95% confidence interval (CI). A total of 279 relevant clinical trials were included. Herbals containing green tea, Phaseolus vulgaris, Garcinia cambogia, Nigella sativa, puerh tea, Irvingia gabonensis, and Caralluma fimbriata and their active ingredients were found to be effective in the management of obesity and metabolic syndrome. In addition, C. fimbriata, flaxseed, spinach, and fenugreek were able to reduce appetite. Meta‐analysis showed that intake of green tea resulted in a significant improvement in weight ([SMD]: −0.75 [−1.18, −0.319]), body mass index ([SMD]: −1.2 [−1.82, −0.57]), waist circumference ([SMD]: −1.71 [−2.66, −0.77]), hip circumference ([SMD]: −0.42 [−1.02, −0.19]), and total cholesterol, ([SMD]: −0.43 [−0.77, −0.09]). In addition, the intake of P. vulgaris and N. sativa resulted in a significant improvement in weight ([SMD]: −0.88, 95 % CI: [−1.13, −0.63]) and triglyceride ([SMD]: −1.67, 95 % CI: [−2.54, −0.79]), respectively. High quality trials are still needed to firmly establish the clinical efficacy of the plants in obesity and metabolic syndrome.

Metabolic Impact of Flavonoids Consumption in Obesity: From Central to Peripheral

“…In humans and animal models, flavanols or flavanols-rich foods (mainly, cocoa or tea derivates) have demonstrated the ability to reduce body weight, decrease waist circumference and fat percentages, improve glucose metabolism in individuals with type 2 diabetes, obesity or MetS and increase energy expenditure [ 75 , 131 , 132 , 133 , 134 , 135 , 136 , 137 , 138 , 139 ]. One of the most described molecular mechanism underlying theses effects are the activation of the AMPK enzyme [ 140 ].…”

Nanophytomedicines for the Prevention of Metabolic Syndrome: A Pharmacological and Biopharmaceutical Review

“…Oral administration of plant extracts is shown to be effective on MetS and its complication by reducing visceral obesity, systolic and diastolic blood pressure, and blood glucose. Additionally, medicinal plants enhance insulin secretion and cardiovascular function, and suppress gluconeogenesis, inflammation and oxidative stress (Naseri et al, 2018;Payab et al, 2019). The main mechanisms of medicinal plants for managing MetS are presented in Figure 2.…”

Apoptosis Exerts a Vital Role in the Treatment of Colitis-Associated Cancer by Herbal Medicine

“…Overall, no serious adverse effects have been reported by the studies conducted in herbal medicine Payab et al, 2020). There was reportedly a low risk of adverse events associated with the uses of American ginseng, Licorice, Ginger, and Lentinula edodes in maintaining well-being, decreasing nausea or vomiting in early-stage pregnant women, ameliorating postoperative sore throat, and preventing nodal metastasis in breast cancer patients, respectively (Arring et al, 2018;Stanisiere et al, 2018;Kuriyama and Maeda, 2019).…”

“…Generally, herbal medicines exert low toxicity and have no serious side effects even with a long period of use; the typical side effects are slight skin or gastrointestinal disorders like skin rash and nausea. This suggests that herbal medicines have a relatively wide range of safety (Payab et al, 2020).…”