Background: The adverse effects of obesity on human health necessitate the development of effective interventions for the prevention and treatment of obesity. Mixture of natural products, including crude extracts and isolated pure natural compounds can cause a body weight reduction and prevent diet-induced obesity. Consequently, they have been widely utilized in treating obesity.

Obesity is a universal health concern that can lead to serious diseases. The side effects of synthetic anti-obesity drugs necessitate the finding of suitable natural/herbal alternatives. Mother nature offers a wide range of plants with medicinal properties that include crude extracts and isolated compounds which are effective for controlling and reducing weight gain. Obesity was induced in 60, 3-week-old male ICR mice, using high-fat diet (60% dietary energy from fat) for 16-week. The mice were divided at random into six groups with 10 mice: mice fed with high-fat diet (HFD) only, mice fed normal diet only (NC), and orlistat at 15.9 mg/kg (HFD+Orlistat), and mice in three other high-fat diet groups treated with methanolic leaf extract of Clinacanthus nutans (MECN) at 500, 1000 and 1500 mg/kg. After 21-day of the treatment, MECN significantly reduced (P<0.05) the body weight, visceral fat and muscle saturated fatty acid compositions. There was also significant downregulation of HSL, PPAR α and PPAR γ and SCD genes expressions in the obese mice treated with 1500 mg/kg MECN compared to the HFD group. Therefore, MECN is a potentially useful natural supplement for alleviating obesity and obesity-mediated metabolic diseases.