제주 자생식물 54종을 대상을 70% 메탄올로 추출하여, 총페놀 함량, DPPH radical 소거능, xanthine oxidase(XOD), tyrosinase 저해활성을 측정한 후, 생리활성이 높은 5가지 식물을 선정하여 고압 유기용매(100% 메탄올, 13.6 MPa, $40^{circ}C$)로 추출하여 DPPH, tyrosinase, elastase 저해활성을 측정하였다. 70% 메탄올 추출물의 총페놀 함량은 새우나무, 이질풀, 아그배나무, 자금우, 짚신나물이 250 mg GAE/g 이상으로 높은 함량을 나타내었다. DPPH radical 소거활성은 백량금이 94.1%로 가장 높았다. DPPH radical 소거활성과 총페놀 함량 사이에는 높은 상관관계($R^2=0.87$)를 나타내었다. Tyrosinase 저해활성은 이삭여뀌, 붉나무, 사방오리나무, 소귀나무가 85% 이상을 나타내었으며, XOD 저해활성은 이삭여뀌와 소귀나무가 90% 이상을 나타내었다. 고압 유기용매 추출물은 70% 메탄올 추출물과 마찬가지로 DPPH 소거능과 tyrosinase 저해활성이 높았다. Tyrosinase 와 elastase의 저해활성에 대한 $IC_{50}$은 자금우가 각각 802와 88 ppm이었고, 소귀나무가 각각 959와 66 ppm이었다.
Fifty-four natural plants from Jeju Island, Korea were extracted by 70% methanol. The extracts containing the highest total phenolic contents (TPC) (>250 mg gallic acid equivalents/g dry sample) were obtained from Ostrya japonica, Geranium thunbergii, Malus sieboldii, Ardisia japonica, and Agrimonia pilosa. DPPH inhibition activity was greatest in Ardisia crenata at 94.1%. A high correlation was observed between DPPH inhibition activity and TPC ($R^2=0.87$). Tyrosinase inhibition activities of more than 85% were obtained from the extracts of Persicaria filiformis, Rhus javanica, Alnus firma, and Myrica rubra. On the other hand, the P. filiformis and M. rubra extracts each showed more than 90% XOD inhibition activity. The five natural plants with the highest biological activities were also extracted by pressurized liquid (PLE, 100% methanol, 13.6 MPa, $40^{circ}C$). The DPPH and tyrosinase inhibition activities were almost the same in both the 70% methanol and PLE extracts. The $IC_{50}$ for tyrosinase and elastase inhibition activities in PLE were 802 and 88 ppm in A. japonica, and 959 and 66 ppm in M. rubra, respectively.
