Characteristics of Pressurized Liquid Extracts from Natural Plants in Jeju

Abstract

제주 자생식물 20종을 대상으로 고압용매 추출하여 총고형분 함량, 총페놀 함량, 통합적 항산화 능력, 세포독성 및 NO 생성 저해 활성, GC/MS에 의한 개별폴리페놀 성분을 정성·정량하였다. (1) 제주 자생식물 20종을 대상으로 고압용매 추출 (추출용매 100% MeOH, 추출 온도 40℃, 추출 압력 13.6 MPa, 추출 시간 10분) 하여 총고형분 함량, 총페놀 함량과 통합적 항산화 능력을 측정함으로써, 고압용매 추출에 의한 폴리페놀 성분의 추출 가능성 여부를 확인 하였다. 고압용매 추출물의 총고형분 추출수율은 붉나무, 말오줌때, 사방오리나무, 사람주나무, 팥배나무가 각각 21.8, 21.5, 21.1, 20.7, 20.1%로 가장 높았다. 총페놀 함량은 아그배나무가 68.3 mg GAE/g dry sample로 가장 높았고, 다음으로 사람주나무, 석위, 말오줌때가 각각 57.6, 56.6, 55.1 mg GAE/g를 나타내었다. 수용성 항산화 능력은 이질풀, 사람주나무, 산딸나무, 붉나무가 각각 598, 394, 293, 270 μmol ascorbic acid equivalents/g로 높았고, 지용성 항산화 능력은 백량금, 새우나무, 이질풀, 붉가시나무가 611, 314, 296, 242 μmol trolox equivalents/g로 높았다. (2) 사람주나무를 대상으로 추출변수 (추출용매의 종류 및 농도, 추출횟수, 추출온도, 추출압력)를 달리하여 고압용매 추출하고 총고형분 함량과 총페놀 함량을 측정하여 고압용매 추출조건을 최적화하였다. 추출수율은 용매 종류 및 농도, 추출 횟수, 추출온도에 의하여 변화되었다. 추출용매에 따른 고압용매 추출물의 총고형분 추출수율은 H₂O, MeOH, EtOH가 각각 17.3, 17.9, 8.4%로 MeOH 추출물이 가장 높았고, 총페놀 함량도 H₂O, MeOH, EtOH이 각각 48.8, 50.4, 27.2 mg GAE/g로 MeOH 추출물이 가장 높았다. 추출용매의 농도에 따른 고압용매 추출물의 총고형분 추출수율은 MeOH:H₂O (40:60, 60:40 v/v)와 EtOH:H₂O (40:60, 60:40 v/v)가 각각 24.4, 23.8, 23.6, 22.1%로 MeOH:H₂O (40:60, v/v) 추출물이 가장 높았고, 총페놀 함량은 MeOH:H₂O (40:60, 60:40 v/v) 와 EtOH:H₂O (40:60, 60:40 v/v) 추출물이 각각 85.0, 84.3, 90.6, 76.8 mg GAE/g로 EtOH:H₂O (40:60, v/v)추출물이 가장 높았다. 추출횟수가 증가할수록 총고형분 추출수율과 총페놀함량은 증가하였다. 추출온도에 따른 고압용매 추출물의 총페놀 함량은 추출온도가 40℃(97.4 mg GAE/g)에서 50℃ (108.3 mg GAE/g)으로 증가하였을 때 11% 증가하였으나, 그 이상의 추출온도에서는 변화가없었다. 추출압력 증가에 따른 고압용매 추출물의 총고형분 추출수율과 총페놀 함량은 추출압력에 관계없이 변화가 없었다. 고압용매 최적추출조건은 추출용매와 농도 EtOH:H₂O (40:60, v/v), 추출횟수 2회, 추출온도 40℃, 추출압력 10.2 MPa 이었다. (3) 고압용매 최적추출조건에서 제주 자생식물 20종을 추출하여 항산화 활성, 세포독성 및 NO 생성 저해 활성, 폴리페놀 성분을 동정·정량하여 식품산업에 응용할 천연항산화소재로서의 가능성을 검정하였다. 고압용매 추출물의 추출수율은 이삭여뀌가 28.5%로 가장 높았으며, 사람주나무, 귀룽나무, 말오줌때가 각각 27.3, 25.8, 25.2%를 나타내었다. 총페놀 함량은 새우나무, 사람주나무, 이질풀, 짚신나물, 석위가 각각 105.4, 105.1, 104.4, 92.2, 90.6, 90.5 mg GAE/g로 가장 높았다. 수용성 항산화 능력은 이질풀과 석위가 976, 948 μmol ascorbic acid equivalents/g로 가장 높았고, 지용성 항산화 능력은 백량금과 이질풀이 945, 520 μmol trolox equivalents/g로 가장 높았다. GC/MS에 의하여 폴리페놀 성분을 동정한 결과 8개의 폴리페놀 피크를 얻었는데, gallic acid와 catechin이 가장 많이 함유되어 있었다. 폴리페놀 전체 함량은 catechin이 많이 함유된 새우나무와 gallic acid가 많이 함유된 사람주나무가 2,970 ppm, 2,963 ppm로 가장 높았다. 세포독성을 고려한 NO 생성 저해 활성인 선택지수는 사람주나무, 사방오리나무, 산딸나무, 아그배나무가 각각 4.5, 3.4, 2.3, 2.2로 자생식물 추출물 중 가장 높았다. 자금우, 된장풀, 아그배나무, 귀룽나무, 붉나무 추출물은 HS-68 세포에 대한 독성이 없었다.

Twenty natural plants collected from Jeju were extracted by pressurized organic solvent. Extraction yields of total soluble solids (TSS) and total phenolics (TP), integral antioxidative capacity, individual phenolic compounds by GC/MS, and cell toxicity and NO production inhibitory activity were measured. (1) Twenty natural plants collected from Jeju were extracted by pressurized organic solvent (100% MeOH, 40℃, 13.6 MPa, 10 min). Extraction yields of total soluble solids (TSS) and total phenolics (TP), and integral antioxidative capacity were evaluated. Extraction yields of TSS were higher as 21.8, 21.5, 21.1, 20.7, and 20.1% in Rhus javanica, Euscaphis japonica, Alnus firma, Sapium japonicum, and Sorbus alnifolia, respectively. Higher TP (mg GAE/g) were obtained from Malus sieboldii (68.3), Sapium japonicum (57.6), Pyrrosia lingua (56.6), and Euscaphis japonica (55.1). Integral antioxidative capacities of water-soluble substances were 598, 394, 293, and 270 μmol ascorbic acid equivalents/g in Geranium thunbergii, Sapium japonicum, Cornus kousa, and Rhus javanica, respectively. Integral antioxidative capacities of lipid-soluble substances were 611, 314, 296, and 242 μmol trolox equivalents/g in Ardisia crenata, Ostrya japonica, Geranium thunbergii, and Quercus acuta, respectively. (2) Sapium japonicum, a natural plant in Jeju, was extracted by a pressurized liquid. Operating parameters such as the type of solvent, the ratio of solvent to water, temperature, pressure, and number of extraction steps were investigated as the main variables that influence the extraction efficiencies of total soluble solids (TSS) and total phenolics (TP). TP contents were affected by the type of solvent, solvent-water ratio, extraction step and temperature. Higher extraction yields (17.9 and 17.3%) of TSS were obtained when MeOH and H₂O were used as the extraction solvents. MeOH extracted the highest level of TP as 50.4 mg GAE/g compared with 48.8 and 27.2 mg GAE/g with H₂O and EtOH, respectively. EtOH:H₂O (40:60, v/v) was found to be the best solvent for TP extraction as 90.3 mg GAE/g compared with 85.0, 84.3, and 76.8 mg GAE/g in MeOH:H₂O (40:60, 60:40, v/v) and EtOH:H₂O (60:40, v/v), respectively. TSS and TP were increased with the increase of the number of extraction steps. TP content was increased by 11% as the extraction temperature was increased from 40℃ (97.4 mg GAE/g) to 50℃ (108.3 mg GAE/g). Extraction pressure had no effect on the extraction efficiency. The optimum extraction conditions of TSS and TP were ; 40% EtOH, 2 extraction steps, temperature 50℃, and pressure 10.2 MPa. (3) Twenty natural plants collected in Jeju were extracted at optimized pressurized liquid extraction condition (40% EtOH, 50℃, 13.6 MPa, 10 min). Extraction yields of total soluble solids (TSS) and total phenolics (TP), integral antioxidative capacity (IAC), individual phenolics by GC/MS, and cell toxicity and NO production inhibitory activity were evaluated. Extraction yield of TSS was the highest in Persicaria filiformis as 28.5% with the decreasing order of 27.3, 25.8 and 25.2 % in Sapium japonicum, and Prunus padus, respectively. Ostrya japonica and Sapium japonicum showed the highest TP (105.4 and 105.1 mg GAE/g), followed by Geranium thunbergii (104.4), Agrimonia pilosa (92.2), Pyrrosia lingua (90.6), and Prunus padus (90.5). IAC of water-soluble substances were higher as 976 and 948 μmol ascorbic acid equivalents/g in Geranium thunbergii and Pyrrosia lingua, respectively. IAC of lipid-soluble substances were 945 and 520 μmol trolox equivalents/g in Ardisia crenata, Geranium thunbergii and Pyrrosia lingua, respectively. Eight phenolic compounds were identified by GC/MS from the extracts of pressurized liquid extracts. Gallic acid and catechin were the predominant phenolics among the ones identified in the extracts of natural plants. The sum of the individual phenolics quantified by GC/MS were higher in Ostrya japonica and Sapium japonicum as 2,970 and 2,963 ppm. The extracts of Sapium japonicum, Alnus firma, Cornus kousa, and Malus sieboldii indicated NO production inhibitory activity with much less toxity. The extracts from Ardisia japonica, Desmodium caudatum, Malus sieboldii, Prunus padus, and Rhus javanica did not affect cell toxicity using HS-68 cells.