Anti‐acne activity of Selaginella involvens extract and its non‐antibiotic antimicrobial potential on Propionibacterium acnes

Acne is a typical condition of adolescence and is caused by multi‐factorial events including hormonal, microbiological and immunological mechanisms. Although there has been much debate about the direct involvement of bacteria, Propionibacterium acnes is now believed to contribute to the inflammatory stages of the condition, and thus initiate the inflamed lesion. The present study examined the anti‐acne properties of the Selaginella involvens extract (SIE) in cell models. Primarily, SIE was not found to be cytotoxic under 50 µg/mL, and revealed the inhibitory effect on both nitric oxide (NO) production and iNOS/IL‐1β expression as well as the NO scavenging effect. The IL‐1α and IL‐8 cytokines, triggering the inflammatory acne response, were also inhibited in keratinocytes when stimulated with viable P. acnes. Furthermore, SIE was found to have an antioxidant effect in a dose‐dependent manner in the hydroxyl radical‐mediated oxidation test. Finally, it was found that SIE has non‐antibiotic antimicrobial activity at a dose greater than 100 µg/mL on P. acnes. In conclusion, SIE may be a safe non‐antibiotic anti‐acne source in the therapeutic application of the treatment of acne development by reducing the chance of non‐specific initiation and augmentation phase of the inflammatory response. Copyright © 2007 John Wiley & Sons, Ltd.