Pharmacological Activity of Cha-Miang (Camellia sinensis var. assamica) in High Fat Diet-Induced Insulin-Resistant Rats

Obesity, a major global health concern, is represented by an accumulation of adipose tissue and body mass, leading to a higher incidence of non-communicable diseases (NCDs). <i>Camellia sinensis</i> var. <i>assamica</i>, known as cha-miang, contains catechin and its derivatives, which have been reported to affect several health-related concerns such as anti-cancer, anti-inflammatory, anti-hyperlipidemia, and against cardiovascular disease. The research aimed to examine the anti-obesity and insulin resistance effects of fresh cha-miang extract (CME) and fermented cha-miang extract (FCME), and to investigate the anti-obesity and anti-diabetic effects of CME and FCME in obese rats generated by a high-fat diet. The extracts demonstrated significant antioxidant potential, with CME demonstrating greater DPPH radical scavenging activity, whereas FCME excelled in ABTS radical scavenging. In the animal model, CME and FCME significantly reduced body weight, plasma insulin levels, insulin resistance, and accumulation of fat compared to the obese control group. Moreover, plasma biochemical analysis indicated that both extracts enhanced lipid profiles by reducing cholesterol, triglycerides, and LDL-cholesterol levels, while elevating HDL-cholesterol. Histological analysis revealed decreased hepatic fat accumulation, especially when extracts were concurrently treated with metformin. The research indicates that CME and FCME, especially in conjunction with metformin, have potential anti-obesity and anti-insulin resistance benefits attributed to their abundant polyphenolic content and antioxidant characteristics. This indicates that cha-miang may serve as an effective option for the management of obesity and metabolic diseases.