Bioactive Flavonoids From Tsaoko Fructus: Antioxidant Capacity and Protection on UV-Damaged Cells and Stimulation to Caenorhabditis elegans Antioxidant System

Tsaoko Fructus (TF), the dried ripe fruit of Amomum tsaoko Crevost et Lemarie (A. tsaoko), a dietary medicine plant, has been demonstrated to have high antioxidant activity. The main objective of this research was to investigate the isolation and purification of TF flavonoids ([TFFT, TFFC, and TFFP], TFFs) and their chemical constituents and antioxidant effects by in vitro and in vivo experiments. LC-MS/MS was used to clarify the chemical substance basis. The results of antioxidant activity in vitro showed that TFFs had excellent DPPH and ABTS radical scavenging capacity, FRAP, and total reducing power. UVB-damaged HaCaT cells and C. elegans models were used to study the effect of TFFs on oxidative stress. Results revealed that TFFS could significantly postpone oxidative damage in UVB-induced HaCaT cells by suppressing the ROS, MDA, TNF-α, and MMP-1 production and increasing the activity of SOD, CAT, and GSH-Px. Furthermore, TFFs could ameliorate heat resistance and oxidative damage of C. elegans. qRT-PCR results showed that TFFs could upregulate the mRNA expressions of gst-10, sod-3, and ctl-1 in C. elegans, indicating TFFs can promote the stress resistance of C. elegans by improving the capacity of the antioxidant oxidase system. Overall, these findings suggested that TFFs may be used as an antioxidant to postpone oxidative stress conditions.