Piperidine alkaloids from Piperretrofractum Vahl. protect against high-fat diet-induced obesity by regulating lipid metabolism and activating AMP-activated protein kinase

► Piperidine alkaloids from Piperretrofractum Vahl. (PRPAs), including piperine, pipernonaline, and dehydropipernonaline, are isolated as the anti-obesity constituents. ► PRPA administration significantly reduces body weight gain without altering food intake and fat pad mass. ► PRPA reduces high-fat diet-induced triglyceride accumulation in liver. ► PRPAs attenuate HFD-induced obesity by activating AMPK and PPARδ, and regulate lipid metabolism, suggesting their potential anti-obesity effects.