Role of the major terpenes of Callistemon citrinus against the oxidative stress during a hypercaloric diet in rats

Abstract

1,8-Cineole, limonene and α-terpineol are the major terpenes present in Callistemon citrinus. This study reports for the first time that terpenes attenuate the oxidative stress in rats fed with high-fat-sucrose diet (HFSD) via antioxidant and anti-inflammatory mechanisms. Thirty-six male Wistar rats were divided into six groups (n = 6). Control (fed standard food, HFSD (fed with 41.7% fat and 16.6% sucrose), HFSD + 1,8-cineole (0.88 mg/kg body weight), limonene (0.43 mg/kg body weight), α-terpineol (0.32 mg/kg body weight) and a mixture of the three terpenes, given daily by gavage for 15 weeks. Morphometric and biochemical parameters were taken. Paraoxonase (PON1), reduced glutathione (GSH), lipid peroxidation products malondialdehyde (MDA) and hydroxyalkenals (HNE), advanced oxidation protein products (AOPP) and pro-inflammatory cytokines were measured in liver homogenates. All terpenes showed a remarkable reduction in weight gain, fat deposition, serum glucose and, triacylglycerol levels. However, terpenes presented different effects on the hepatic cell and the oxidative biomarkers. Conversely, the three terpenes and the mixture showed the same positive effect on the tumor necrosis factor alpha (TNFα), interleukin-6 (IL-6), leptin and adiponectin levels. Finally, 1,8-cineole, limonene and α-terpineol demonstrate significant anti-inflammatory effects and differential effects on the oxidative stress, suggesting the importance of these terpenes in Callistemon citrinus activities.