사방오리(Alnus firma) 추출물의 in vitro 항산화 활성

In Vitro Antioxidant Activity of Alnus firma Extracts

Abstract

본 연구는 사방오리 추출 분획물의 항산화 활성을 검증하기 위하여 시행되었다. 사방오리는 메탄올(MeOH) 분획에 가장 높은 총 페놀화합물($452.80{\pm}7.01{\mu}g$ gallic acid equivalents/mg)을 그리고 에틸에세테이트(EA) 분획 에 가장 높은 총 플라보노이드 함량($112.29{\pm}11.14{\mu}g$ rutin equivalents/mg)과 가장 높은 총 항산화 활성($936.23{\pm}0.07{\mu}g$ ${\alpha}$-tocopherol equivalents/mg)을 가지고 있었다. 사방오리의 용매 추출분획물에 대한 항산화 활성은 아스코빅산 등 표준 물질과 비교하여 1,1-diphenyl-2-picrylhydrazyl (DPPH) 라디칼 소거능 측정, 슈퍼옥사이드 음이온 라디칼 소거능 측정, ${\beta}$-carotene-linoleate 에세이, 환원력 측정, ferric thiocyanate법으로 지질과산화 억제력 측정 그리고 금속 킬레이팅능 측정 등 다양한 항산화 활성을 측정하였다. $250{\mu}g/ml$ 농도의 사방오리 EA와 MeOH 분획은 DPPH 라디칼 소거능 측정에서 각각 92.43와 89.20% 항산화 활성을 가지고 있었다. $50{\mu}g/ml$의 EA분획은 72.49% 슈퍼옥사이드 음이온 라디칼 소거능을 보였으며 이는 gallic acid의 소거능(60.88%)보다 조금 높았다. 또한 ${\beta}$-carotene-linoleic acid 시스템에 의한 과산화 억제능 조사에서 0.5과 1 mg/ml 농도의 EA 분획이 각각 73.45와 73.29% 억제능을 보였다. 항산화 활성은 EA 분획 > BuOH 분획 > DCM분획 > HX분획 순 이였다. 이상의 본 연구 결과에서 사방오리는 천연 항산화제제 개발을 위한 용이하게 접근 가능한 잠재적인 자원으로 판단된다.

This study evaluated the antioxidant activity of the extract and fractions of Alnus firma. Alnus firma had the highest total phenolic content ($452.80{\pm}7.01{\mu}g$ gallic acid equivalents/mg) in a methanol (MeOH) fraction and the highest total flavonoid content ($112.29{\pm}11.14{\mu}g$ rutin equivalents/mg) and antioxidant capacity ($936.23{\pm}0.07{\mu}g$ ${\alpha}$-tocopherol equivalents/mg) in an ethylacetate (EA) fraction. The antioxidant activities of various solvent extract fractions of Alnus firma were evaluated using various antioxidant assays, including ${\beta}$-carotene-linoleate assay, reducing power assay, 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging assay, metal chelating activity assay, superoxide anion radical scavenging assay, and lipid peroxidation inhibition assay using the ferric thiocyanate method. These activities were compared with those of ascorbic acid, butylated hydroxyanisole (BHA), gallic acid (GA), butylated hydroxytoluene (BHT), and ${\alpha}$-tocopherol. First, at a $250{\mu}g/ml$ concentration, the EA and MeOH fractions of A. firma showed 92.43% and 89.20% DPPH radical scavenging activity, respectively. Second, $50{\mu}g/ml$ of the EA fraction exhibited 72.49% superoxide anion radical scavenging activity, a little greater than the same dose of GA (60.88%). Finally, 0.5 and 1 mg/ml of the EA fraction showed 73.45% and 73.29% inhibition of peroxidation in the ${\beta}$-carotene-linoleic acid system, respectively. The decreasing order of reducing power was EA fraction > n-butanol (BuOH) fraction > dichloromethane (DCM) fraction > n-hexane (HX) fraction. The results obtained in the present study indicated that Alnus firma can be used as an easily accessible potential source of natural antioxidants.

Fig. 1. Free radical scavenging activity of MeOH, HX, DCM and EA fractions of Alnus firma by 2,2-diphenyl-1-picrylhydrazyl (DPPH) method.

Fig. 2. Superoxide anion radical scavenging activity of MeOH, HX, DCM and EA fractions of Alnus firma by PMS/ NADH-NBT method.

Fig. 3. Antioxidant activities of Alnus firma extracts using the β-carotene linoleate model system. L-ascorbic acid and BHA were used as positive controls.

Fig. 4. Reducing power of MeOH, HX, DCM, EA and BuOH fractions of Alnus firma.

Fig. 5. Inhibition of lipid peroxidation of Alnus firma extracts. Ferric thiocyanate (FTC) method was used for determination of lipid peroxidation.

Fig. 6. Metal chelating effect of organic solvent-fractions of Alnus firma.

Table 1. Extraction yields, total phenolic contents, total flavonoid contents, total antioxidant contents and total reducing power in crude Alnus firma extracts