Antioxidant effect of the constituents of susabinori (Porphyra yezoensis)

Abstract

The antioxidant activities of several extracts from Susabinori (Porphyra yezoensis) were measured by the ferric thiocyanate method and the thiobarbituric acid method. The methanol, acetone, ethyl acetate, and hexane extracts, and the chloroform-soluble and water-soluble fractions from the chloroform-methanol extract exhibited higher activities than α-tocopherol. The hot water extract showed little activity. Thinlayer chromatography analysis of the active extracts suggested the existence of several antioxidants. The activity of the chloroform soluble fraction was due to chlorophyll analogs. A strong antioxidant was isolated from the methanol extract, accompanied by several amino acids such as leucine and phenylalanine. This compound was identified as usujilene, a kind of mycosporine-glycine like amino acid.Paper no. J8916 in JAOCS 76, 649-653 (May 1999).Seaweeds, such as laver and kelp, are commonly eaten in Japan and their high dietary fiber and vitamin content have stimulated their evaluation as health foods. In addition, seaweeds contain high levels of polyunsaturated fatty acids (1). Although polyunsaturated fatty acids are very easily oxidized, seaweeds are known to resist oxidation during storage. Fujimoto et al.(2) reported the antioxidant effect of 21 species of marine algae and found that the phospholipid fraction in arame (Eisenia bucyclis) showed efficient activities. Tutour (3) described that brown algae had strong antioxidant activity and that they synergistically enhanced the effect of vitamin E. Furthermore, Nishibori et al. (4) identified pheophytin a, one of the chlorophyll analogs, as a major antioxidant in Aonori (Enteromorpha sp.). In this paper, we describe the antioxidant effect of several extracts from Susabinori (Porphyra yezoensis), one of laver, and the isolation of antioxidants from the methanol extract. EXPERIMENTAL PROCEDURESMaterials and extraction. Cultured P. yezoensis was purchased from Akashiura Fisherman's Union (Hyogo, Japan) in February 1995. A part (10 g each) of the ground freeze-dried material was extracted independently with 200 mL of n-hexane, ethyl acetate, acetone, chloroform/methanol (2:1), methanol, and hot water (90°C) under stirring. Each extract was filtered and concentrated in vacuo. Water was added to the chloroform/methanol extract and then partitioned with chloroform to afford a chloroform-soluble fraction and an aqueous fraction. Antioxidative assay. (i) Ferric thiocyanate method (FTC). The method of Kikuzaki et al. (5) was slightly modified. To a mixture of 2 mg of the fractions of the Susabinori extract, α-tocopherol or isolated compounds in 2 mL of 99.5% ethanol in a vial (φ = 35, h = 80 mm), 2.05 mL of 2.51% linoleic acid in 99.5% ethanol, 4 ml of a 0.05 M phosphate buffer (pH 7.0), and 1.95 mL of water were added. The solution including linoleic acid without any antioxidant or extract was used as control. The vial was placed in an oven at 40°C in the dark. At each test time, to 0.1 mL of this sample solution were added 9.7 mL of 75% ethanol and 0.1 mL of 3...

Photoprotective compounds from marine organisms

“…The antioxidant activities of the MAAs glycine and usujilene have been reported to inhibit lipid peroxidation in aqueous extracts of marine organisms and to scavenge 1 O 2 generated from certain endogenous photosensitizers [147,209]. Yoshiki et al [227] reported a new antioxidant compound from the MAA porphyra-334 by heat treatment.…”

Evaluation of phenolic contents and antioxidant activities of brown seaweeds belonging to Turbinaria spp. (Phaeophyta, Sargassaceae) collected from Gulf of Mannar

“…The higher ABTS radical scavenging ability exhibited by the n-hexanic fraction may be explained due to the presence of carotenes/other pigments with long hydrocarbon chain [4] . There are reports which showed that also reported that hexane, chloroform and methanol extracts of Porphyra yezoensis exhibited antioxidant activities [19] attributed to the presence of β-carotene, chlorophyll analogues (pheophytin) and amino compounds (leucine, phenylalanine and mycosporine-like amino acid, usujirene). There are also other reports claiming that seaweeds contain antioxidant compounds which include some pigments such as fucoxanthin and astaxanthin, polyphenols such as phlorotannins, chlorophyll related compounds, phospholipids, flavonoids, bromophenols and polysaccharides [4,15] .…”

Mycosporine-Like Compounds in Chlorolichens: Isolation from Dermatocarpon luridum and Dermatocarpon miniatum, and their Photoprotective Properties

“…Therefore, we investigated some biological activities related to UV filter requirements including the ethyl derivative 3, which exhibited a higher molar extinction coefficient 21 295 M − 1 .cm −1 . Until now, most mycosporine-like compounds tested for their antioxidant activities are either pure imino-mycosporines or a mixture of several imino-mycosporines [7,[22][23][24][25][26]. Thus, oxo-mycosporines are less reported, and only mycosporine glycine and mycosporine glutaminol glucoside have been tested so far [23,[27][28][29].…”