Antioxidant effects of bioactive compounds isolated from cordyceps and their protective effects against UVB-irradiated HaCaT cells

Excessive free radicals, generated from the metabolic reaction in organisms, have been implicated in many human diseases as well as aging process. Nowadays, many synthetic substances have been developed as anti-oxidation cosmetic ingredients. However, man-made antioxidants often have certain toxicity and side effects, which make their application under strict control. Therefore, more and more researchers focus on natural antioxidants because of their advantages.

In this study, CE obtained from natural Chinese medicine was used to investigate whether it had antioxidant effect in vitro and repair effect on HaCaT cell damage caused by UVB.

UV-Vis and HPLC were adopted for qualitative and quantitative analysis of CE. We investigated the antioxidant potential of CE by assessing its ABTS⁺ , DPPH•, hydroxyl (OH•), and superoxide anions ( $$ ) free-radical quenching ability. The safety of CE was studied by CCK-8 assay. To evaluate the anti-oxidation effect of CE on UVB-induced damage on HaCaT cells, superoxide dismutase (SOD) activity, and malondialdehyde (MDA) content were tested.

Experiment data showed that the CE displayed high scavenging ability: ABTS⁺ , DPPH•, OH•, and $$ quenching rates were 88%, 64%, 94%, and 58%, respectively. Furthermore, after UVB radiation (30 mJ/cm² ), adding CE (50-500 μg/mL) could increase the SOD activity in HaCaT cells and reduce the MDA contents.

All results illustrate that the CE shows significant antioxidant effect on scavenging free radicals in vitro. Besides, the CE can repair UVB-induced oxidant damage by improving SOD activity and reducing MDA content.