Chemical identification of the Viola phillipina extracts and their anti-acne activity: A comparison with isotretinoin and salicylic acid.

Since acne is a multifactorial condition, its treatment remains challenging. The multi-target efficacy of plant extracts may be a better way to treat it. In this paper, the components of Viola philippica extracts with different polarity were analyzed by HPLC, and the anti-acne activities were studied from sebum inhibition, anti-inflammatory and bacteriostasis. Results revealed that 6,7-Dihydroxycoumarin was enriched in dichloromethane (DE，308.125 ± 0.151 μg / mg) and ethyl acetate (EAE，344.748 ± 0.071 μg / mg) extracts, while cichoriin accumulated in ethanol (EEP，56.494 ± 0.019 μg / mg) and n-butanol (BE，42.888 ± 0.069 μg / mg) extracts. In androgen-stimulated SZ95 cells, the extract reduced lipid accumulation via Androgen Receptor (AR) downregulation. In Cutibacterium acnes(C. acnes),-stimulated HaCaT cells, it suppressed tumor necrosis factor-α (TNF-α) and Interleukin-8(IL-8) secretion by lowering Toll-like receptor 2 (TLR2). Both DE and EAE demonstrated significant sebum-inhibiting and anti-inflammatory activities within safe concentrations, along with strong antibacterial effects against Staphylococcus epidermidis (S. epidermidis) and C. acnes-surpassing isotretinoin in efficacy. EAE showed exceptional sensitivity toward S. epidermidis, with a Minimum Inhibitory Concentration (MIC) of 0.391 mg/mL. Its Minimum Bactericidal Concentration (MBC) was 0.780 mg/mL. Spearman correlation confirmed that anti-acne activity was positively correlated with synergistic effects of caffeic acid and 6,7-dihydroxycoumarin. In summary, Viola philippica extract exhibits promising multi-target anti-acne potential, supporting its development as a novel multifunctional treatment strategy.