Antifungal and Antioxidant Activities of Castanea crenata Inner Shell Extract against Dandruff-causing Malassezia furfur

Purpose: This study aimed to investigate the potential of Castanea crenata inner shell extract as a natural antidandruff agent. Accordingly, we analyzed the antifungal activity of C. crenata inner shell extract against Malassezia furfur as well as its antioxidant and anti-inflammatory activities. Methods: The collected C. crenata inner shells were extracted with different solvents: hot water (80℃), ethanol (25℃), and methanol (25℃) for 24 h. The antifungal efficacy of the extracts at various concentrations was assessed via a disc diffusion test. DPPH radical scavenging activity, total polyphenol content, and total flavonoid content were also analyzed. The major bioactive components of the extracts were identified using HPLC. Results: Among the solvents tested, methanol was the most effective for antifungal and antioxidant activities. In particular, the antifungal efficacy of methanolic extracts increased in a concentration-dependent manner, with an inhibition zone≤14.2 mm in diameter. The TPC and TFC of the extracts were 151.25 and 88.7 μg/g, respectively. Gallic acid and quercetin were identified as the main components. In addition, the extracts did not exhibit cytotoxic and anti-inflammatory effects at concentrations<0.8% (v/v). Conclusion: This study confirmed that the extract of C. crenata inner shell possesses notable antifungal and antioxidant activities. Therefore, it has potential as a natural ingredient and as an alternative to synthetic chemicals for manufacturing scalp care products. Further work is needed to investigate the mechanistic relationship between antifungal activity and the profile of bioactive compounds.