This study was conducted with the goal of verifying and measuring the antimicrobial effects of evergreen woody species extracts on skin pathogens such as, Staphylococcus aureus, S. epidermidis, Propionibacterium acnes, and Trichophyton mentagrophytes, and suggesting its usability as a functional natural material aimed at skin care.

In this study, chemical substances from the leaves and stems of evergreen woody species from Jeju-do and Wando region were collected by using methanol as a solvent for 30 minutes in ultrasonics waves. In addition, the quantity of moisture content and soluble solid showed a marked difference according to the plant species and parts. There was no characteristic consequent in plant classification, such as family, or genus, etc.

As a result of analyzing the inhibitory activity of extracts from 64 evergreen wood plant species on S. aureus, the study discovered that inhibitory clear zone was formed with leaf extracts from 43 species and stem extracts from 30 species, which were used in this research, and accordingly, their antimicrobial activity was acknowledged and recorded. Among the extract of leaves and stems of 64 species, 10 species leaf extract, such as Elaeocarpus sylvestris var. ellipticus (23.30 mm), etc. showed greater inhibitory activity than methylparaben (4 mg/disc, 13.80 mm) at the control quadrat. Also, it was found that inhibitory activity of su mmer extract was more effective than winter extract against S. aureus among 13 evergreen woody species. This study selected 5 species, E. sylvestris var. ellipticus, Cleyera japonica, Quercus salicina, Camellia japonica, and Ternstroemia gymnanthera whose antimicrobial activity is excellent, to analyze the impact of the extraction condition on inhibitory activity against S. aureus. As for antimicrobial activity consequent on extraction process condition, the inhibitory activity on S. aureus was found to be the highest for the leaf extract of E. sylvestris var. ellipticus (23.3 mm) using 100% methanol in ultrasonic waves for 30 minutes. This study carried out the research to clear up an effective subdividing method using the leaf extract of E. sylvestris var. ellipticus using 100% methanol in ultrasonic waves for 30 minutes, subdividing it in the order of n-hexane, chloroform, ethyl acetate, n-butanol, and water by solvent, and doing comparative analysis of the extraction yield over each subdivided substance and inhibitory activity on S. aureus. As a result, the subdivided substance of n-butanol showed a clear zone, indicating the highest activity among the subdivided substances. This was significantly similar to crude extract (23.3 mm), and exhibited higher inhibitory activity than synthetic antimicrobials-methylparaben and phenoxyethanol.

As a result of analyzing the inhibitory activity of leaves and stems of 64 species of evergreen woody plants on growth and development of S. epidermidis, it was found that the leaf extracts of 6 species and stem extracts of 3 species showed an inhibition clear zone larger than 15.00 mm. In addition, among the leaf extracts of 13 species of evergreen woody plants by season, inhibitory activity of winter extracts on S. epidermidis was found to be more effective compared to su mmer extracts. This study also analyzed the impact of extraction condition on inhibitory activity on S. epidermidis by selecting five species, such as C. japonica, Q. salicina, E. sylvestris var. ellipticus, Rhododendron brachycarpum, and C. japonica, whose antimicrobial activity is excellent. As for antimicrobial activity consequent on extraction processing condition, the leaf extract of C. japonica with methanol for 15 minutes showed the most effective inhibitory activity on S. epidermidis with the 14.1 mm inhibition clear zone. This study carried out the research to clear up an effective subdividing method using the leaf extract of C. japonica using 100% methanol in ultrasonic waves for 30 minutes, subdividing it in the order of n-hexane, chloroform, ethyl acetate, n-butanol, and water by solvent, and doing comparative analysis of the extraction yield over each subdivided substance & inhibitory activity on S. epidermidis. Ethyl acetate subdivided substances indicated the highest activity among subdivided substances by showing 28.1 mm clear zone. This is 1.5 times greater than that of crude extract (19.3 mm). Also, n-butanol subdivided substances (23.0 mm) showed excellent antimicrobial activity in comparison with crude extract (19.3 mm), which was the inhibitory activity higher than synthetic antimicrobials, such as methylparaben and phenoxyethanol.

As a result of the analysis of inhibitory activity of the methanol-using extracts of 64 species of evergreen woody plants on P. acnes, all leaf extracts of 64 species formed the inhibition clear zone against P. acnes, and accordingly their antimicrobial activity was acknowledged. Also, this study found that the leaf extracts of Theaceae and Lauraceae exhibited very effective inhibitory activity on growth and development of P. acnes. This study analyzed the impact of extraction condition on inhibitory activity against P. acnes by selecting five species, T. gymnanthera, C. japonica, Laurus nobilis, C. japonica, and Actinodaphne lanecifolia, whose antimicrobial activity is excellent. In determining the antimicrobial activity consequent on extraction processing condition, the leaf extract of L. nobilis (10.2 mm) processed in methanol with ultrasonic waves for 30 minutes was found to be the highest in inhibitory activity against P. acnes. This study carried out the research to clear up an effective subdividing method by using the leaf extract of L. nobilis processed in methanol with ultrasonic waves for 30 minutes, subdividing it in the order of n-hexane, chloroform, ethyl acetate, n-butanol, and water by solvent, and doing comparative analysis of the extraction yield over each subdivided substance & inhibitory activity on P. acnes. As for the inhibitory activity of the subdivided substance, which was obtained by subdividing the crude extract of Laurus nobilis using a solvent, against P.acnes, the subdivided substance of ethyl acetate showed a 23.3 mm clear zone, showing the highest activity among the subdivided substances. It showed inhibitory activity 1.3 times higher than that of crude extract (10.2 mm) and significantly greater than that of phenoxyethanol (12.5 mm).

As a result of analyzing the inhibitory activity of the leaf extracts of the 64 species of evergreen woody plants obtained through methanol processing against T. mentagrophytes, it was found that leaf extract of 56 species, such as Dendropanax morbiferus, etc. among the leaf extract of 64 species formed the inhibitory clear zone, and accordingly their antimicrobial activity against T. mentagrophytes was acknowledged. Also, the leaf extract of 4 species, such as D. morbiferus (22.60 mm), A. lanecifolia (22.33 mm), Q. acuta (22.27 mm), and Daphne odora (22.13 mm) showed more effective inhibitory activity than a control quadrat-methylparaben (4 mg/disc, 21.40 mm). This study selected 5 species, E. sylvestris var. ellipticus, C. japonica, Q. salicina, C. japonica, and T. gymnanthera, whose antimicribial activity is excellent to analyzed the influence of the extraction condition on inhibitory activity against T. mentagrophytes. In the antimicrobial activity consequent on extraction processing condition, the leaf extract of Q. acuta. (23.7 mm) obtained in methanol with ultrasonic waves for 30 minutes was found to be the highest in inhibitory activity against T. mentagrophytes.

Putting the above data together, the screening process and extraction conditions of evergreen woody species, which exhibited high antimicrobial activity even in low concentrations, were effectively established. As a result, the possibility of the use of evergreen woody species as a functional natural material in the treatment of various skin conditions has been confirmed, which can promote increase in its value as a natural resource and expand its utilization in food, medical, and cosmetic industries in the future.