Antioxidant and Pancreatic Lipase Inhibitory Activities of Panax japonicus (T. Nees) C.A. Meyer.

Obesity and its associated complications, including oxidative stress, pose significant global health challenges. Natural products offer a promising avenue for developing novel therapeutic strategies. In this study, we investigated the potential of Panax japonicus (T. Nees) C.A. Meyer, a traditional medicinal plant known for its antioxidant and anti-obesity properties. A methanol extract of Panax japonicus and its fractions were evaluated for their in vitro antioxidant activities (tested using DPPH and reducing power assays), pancreatic lipase (PL) inhibitory capacities, and underlying mechanisms of action. The results indicated that the ethyl acetate fraction of P. japonicus (PJEA) exhibited the greatest potency, demonstrating strong antioxidant activity and significantly inhibiting digestive enzyme activity (pancreatic lipase). Mechanistic studies revealed that the PL inhibition was of a mixed type, combining both competitive and non-competitive mechanisms. Furthermore, PJEA demonstrated the ability to inhibit the differentiation of preadipocytes, primarily exerting its anti-adipogenic effects by downregulating the mRNA expression of PPARγ and the gene expression of C/EBPα. In addition, the extract suppressed the gene expression of FAS and ACC in adipose tissue. Isolation of the bioactive compounds from PJEA identified kaempferol 3-O-α-L-rhamnoside and catechin, which potentially contribute to the observed anti-obesity effects. Overall, this study highlights P. japonicus as a promising natural ingredient for scavenging free radicals and managing obesity, suggesting its potential for development into functional foods or therapeutic agents.