為瞭解條斑紫菜 (Porphyra yezoensis) 之機能成分，分別以去離子水及95%乙醇萃取，取其萃取物檢測抗氧 化活性，結果顯示水萃物清除DPPH之能力優於95%乙醇萃取物2.8倍，其IC50為386 μg/mL。95%乙醇萃取物之 螯合亞鐵離子能力則比去離子水萃取物約高4.34倍，其IC50為163 μg/mL，還原力雖95%乙醇萃取物稍高但差異 不大；又將Folch’s試劑萃取物分別測定脂肪酸組成及植物固醇含量，結果顯示多元不飽和脂肪酸以二十碳五 烯酸 (eicosapentaenoic acid, EPA)、亞麻油酸 (linolic acid)、花生四烯酸 (arachidonic acid) 及次亞麻油酸 (linolenic acid) 為主，分別約佔33.8、4.2、4.0及2.1%，而主要固醇類為brassicasterol, campesterol, stigmasterol, β-sitosterol, Δ5- avenasterol, 及Δ7-stigmasterol等六種，其含量合計約127.86 ± 0.96 μg/g，以β-穀固醇 (β-sitosterol) 最高約79.50 μg/g。

Porphyra yezoensis was extracted with deionized water and 95% ethanol, respectively. The functional components were investigated by studying the antioxidant activities of the extracts. The results showed the DPPH scavenging ability of the deionized water extracts is 2.8-fold higher than 95% ethanol extracts, with an IC50 of 386 μg/mL. Ferrous ion chelating ability of the 95% ethanol extracts is 4.34-fold higher than deionized water extracts, with an IC50 of 163 μg/mL. Although the reducing power of 95% ethanol extracts is slightly higher than deionized water extracts, there is no significant difference between these two. In addition to deionized water and 95% ethanol, Porphyra yezoensis was also extracted using Folch’s reagent. The extracts were then examined for their fatty acids composition and the amount of phytosterols. The results showed the main composition of fatty acids include 33.8% of eicosapentaenoic acid (EPA, 20 : 5 ω3), 4.2% of linoleic acid, 4.0% of arachnoid acid and 2.1% of linolenic acid. The main contents of steroids are brassicasterol, campesterol, stigmasterol, β-sitosterol, Δ5-avenasterol and Δ7-stigmasterol, with a total amount of 127.86 ± 0.96 μg/g, among which the content of β-sitosterol is the highest at about 79.50 μg/g.