Flavonoids extracted from the roots of Petasites japonicus were evaluated for their cytoprotective, antioxidant, and anti-aging effects. The MTT assay confirmed that cell viability remained above 95% across concentrations up to 12 μg/mL, indicating no cytotoxicity. The extract demonstrated strong DPPH radical scavenging activity in a concentration-dependent manner, reaching 86.7% at 12 μg/mL, which is comparable to vitamin C. ROS scavenging activity also increased with dosage, showing significant suppression at concentrations of 6 μg/mL and above, thus effectively mitigating oxidative stress. Collagen synthesis assays revealed an initial decrease at low concentrations, followed by a clear recovery and significant enhancement at higher doses (10–12 μg/mL). Additionally, the extract inhibited collagenase activity, with notable suppression occurring at concentrations above 10 μg/mL, suggesting protective effects against collagen degradation. Elastase activity was reduced in a dose-dependent manner, achieving over 60% inhibition at 10–12 μg/mL. These results imply that flavonoids have dual functions: they stimulate collagen production while suppressing the enzymes that degrade collagen and elastin. The strong antioxidant and anti-inflammatory potential of these flavonoids likely contributes to their protective effects on dermal structure and function. Collectively, these findings highlight the potential of flavonoids as promising natural ingredients for anti-aging cosmetics and skin health applications.

Steaming is a method that has traditionally been used for medicinal plant extraction. This study investigated nitrite oxide production, ferrous ion chelating activity, α-glucosidase, xanthine oxidase, and acetylcholinesterase inhibitory activities of ethanol, acetone and hot-water extracts of Codonopsis lanceolata prepared by steaming seven times. MTT assay showed that each extract was non-toxic up to a concentration of 700 μg/mL confirming that there was no cytotoxicity in all extracts. The α-glucosidase, xanthine oxidase, and acetylcholinesterase inhibitory activities exhibited by the hot-water extract obtained from steaming seven times were higher (83.1%) than the other extracts. Higher production of nitrite oxide and better ferrous chelating activity was recorded with hot-water extract compared to ethanol and acetone extracts. These results indicated that more steaming of Codonopsis lanceolata extracts would be required to validate the possibility of developing antioxidants. Also, further study is needed to determine if the components present in the tested extracts might be useful in the prevention of Alzheimer's disease. These results showed that hot-water extracts may be useful for their antioxidant and the production inhibitory activity of nitrite oxide. It will be helpful in the investigation of the constituent analysis of the steam-processed product of Codonopsis lanceolata.