Abstract

Phenolic compounds are known to inhibit the nitrosation or oxidation reaction. In the present work, the effects of phenolic compounds including phenolic acids and flavonoids on the nitrite-scavenging and electron donating ability were tested as scavenger of nitrite which is believed to participate in the formation of N-nitroso compounds and investigated as electron donator. The nitrite scavenging ability appeared in all the phenolic acids and showed the highest value at PH 1.2. Among the Phenolic compounds, phenolic acids showed higher nitrite-scavenging action than some flavonoids. Futhermore, the nitrite scavenging action of phenolic compounds was pH dependent highest at pH 1.2 and lowest at pH 6.0. The electron donating ability (EDA) by reduction of ${\alpha},{\alpha}$-diphenyl-${\beta}$-picrylhydrazyl (DPPH) among hydroxybenzoic acids was in the decreasing order of gallic acid, gentisic acid, syringic acid, protocatechuic acid, salicylic acid, vanillic acid, benzoic acid and p-hydroxybenzoic acid. EDA of hydroxycinnamic acids was in the decreasing order of hydrocaffeic acid, caffeic acid, ferulic acid, p-coumaric acid and trans-cinnamic acid. EDA of flavonoids was in the decreasing order of (+)catechin, rutin, quercetin, naringin and hesperidin. Other phenolic compounds were significantly high in electron donating abilities.

천연에 광범위하게 존재하고 있는 각종 폐놀성 화합물은 니트로화 반응의 저해제로 관여하거나 항산화제로 작용하는 것으로 알려져 있어 본 연구에서는 이들 각종 페놀성 화합물의 아질산염 소거작용과 전자공여 작용 유무를 알아보기 위하여 이들 화합들의 농도를 $0.1mM{\sim}6mM$용액을 조제한 후, 이 액 일정량을 이용해 아질산염 소거작용과 전자공여 작용을 비교하였다. 아질산염 소거율에서 phenolic acid류는 높은 활성을 보였으며, 일부는 pH 1.2, 3.0에서 flavonoids보다 높은 활성을 나타내었다. 전자공여능에서 phenolic acid류 가운데 hydroxybenzoic acids는 gallic acid> gentisic acid> syringic acid> protocatechuic acid> salicylic acid> vanillic acid> benBoic acid>p-hydroxy benzoic acid 순으로 나타났으며, hydroxycinnarnic acids가운데 전자공여능의 크기는 hydrocaffeic acid> caffeic acid> ferulic acid> p-coumaric acid>trans-cinnamic acid 순으로 나타났고, flavonoids 가운데에서는 (+)catechin> rutin> quercetin>naringin=hesperidin 순으로 나타났다. 또한 tannic acid를 포함한 기타 phenol성 화합물에 없어서도 높은 전자공여능을 나타내었다.

Keywords

• phenolic compounds;
• flavonoids;
• nitrite-scavenging ability;
• electron donating ability