Extraction and antioxidant capacity of mycosporine-like amino acids from red algae in Japan.

Mycosporine-like amino acids (MAAs) are the natural UV absorbing compounds with antioxidant activity found in microalgae and macroalgae. We collected red algae Asparagopsis taxiformis, Meristotheca japonica, and Polysiphonia senticulosa from Nagasaki, where UV radiation is more intense than in Hokkaido, and investigated the effect of UV radiation on MAAs content. It was suggested that A. taxiformis and M. japonica contained shinorine and palythine, while UV absorbing compound in P. senticulosa could not be identified. The amounts of these MAAs were lower compared to those from Hokkaido. Despite an increase in UV radiation in both region from February to April, MAAs contents of red algae from Nagasaki slightly decreased, while that from Hokkaido significantly decreased. This difference was suggested the amount of inorganic nitrogen in the ocean. Antioxidant activity of MAAs increased under alkaline conditions. The extract containing MAAs from P. senticulosa showed the highest antioxidant activity among four red algae.

Fucoxanthin and Colorectal Cancer Prevention.

Colorectal cancer (CRC), which ranks among the top 10 most prevalent cancers, can obtain a good outcome with appropriate surgery and/or chemotherapy. However, the global numbers of both new cancer cases and death from CRC are expected to increase up to 2030. Diet-induced lifestyle modification is suggested to be effective in reducing the risk of human CRC; therefore, interventional studies using diets or diet-derived compounds have been conducted to explore the prevention of CRC. Fucoxanthin (Fx), a dietary carotenoid, is predominantly contained in edible brown algae, such as Undaria pinnatifida (wakame) and Himanthalia elongata (Sea spaghetti), which are consumed particularly frequently in Asian countries but also in some Western countries. Fx is responsible for a majority of the anticancer effects exerted by the lipophilic bioactive compounds in those algae. Interventional human trials have shown that Fx and brown algae mitigate certain risk factors for CRC; however, the direct mechanisms underlying the anti-CRC properties of Fx remain elusive. Fx and its deacetylated type "fucoxanthinol" (FxOH) have been reported to exert potential anticancer effects in preclinical cancer models through the suppression of many cancer-related signal pathways and the tumor microenvironment or alteration of the gut microbiota. We herein review the most recent studies on Fx as a potential candidate drug for CRC prevention.

Spatial and seasonal variations in the biofunctional lipid substances (fucoxanthin and fucosterol) of the laboratory-grown edible Japanese seaweed (Sargassum horneri Turner) cultured in the open sea.

This work studied the effect of spatial and seasonal differences on the accumulation of functional lipid components in Sargassum horneri (Turner), an edible Japanese seaweed popularly called Akamoku. S. horneri obtained from Samenoura bay area of Japan was laboratory cultured to evaluate the effect of temperature on the accumulation of total lipids (TL), fucoxanthin (Fx) and fucosterol (Fs) by the alga. The laboratory cultured 3 month old S. horneri were cultured in the open sea in two different geographical locations off Usujiri and Matsushima to evaluate the monthly variations, over a year, in their TL, Fx and Fs contents. S. horneri grown off the Usujiri area accumulated the maximum TL close to 193 mg g-1 dry weight during the coldest part of the year. Fx and Fs contributed 5.6% and 16.2% of the TL in S. horneri harvested off Usujiri in February. Further, in spite of being the same species and parent stock, S. horneri grown off the Matsushima area accumulated less TL, Fx and Fs as compared to their Usujiri counterparts. Our study clearly indicates the role of temperature and light apart from nutritional profile and depth of waters where the seaweed was grown on the accumulation of functional lipid components in S. horneri.

EVALUATION OF RECOVERABLE FUNCTIONAL LIPID COMPONENTS OF SEVERAL BROWN SEAWEEDS (PHAEOPHYTA) FROM JAPAN WITH SPECIAL REFERENCE TO FUCOXANTHIN AND FUCOSTEROL CONTENTS(1).

Fucoxanthin (Fx) and fucosterol (Fs) are characteristic lipid components of brown seaweeds that afford several health benefits to humans. This article describes the quantitative evaluation of lipids of 15 species of brown seaweeds with specific reference to Fx, Fs, and functional long-chain omega-6/omega-3 polyunsaturated fatty acids (PUFAs). In addition, fatty-acid composition of selected species was also accomplished in the study. Major omega-3 PUFAs in the brown seaweeds analyzed were α-linolenic acid (18:3n-3), octadecatetraenoic acid (18:4n-3), arachidonic acid (20:4n-6), and eicosapentaenoic acid (20:5n-3). Both Fx (mg · g(-1) dry weight [dwt]) and Fs (mg · g(-1) dwt) were determined to be relatively abundant in Sargassum horneri (Turner) C. Agardh (Fx, 3.7 ± 1.6; Fs, 13.4 ± 4.4) and Cystoseira hakodatensis (Yendo) Fensholt (Fx, 2.4 ± 0.9; Fs, 8.9 ± 2.0), as compared with other brown seaweed species. Studies related to seasonal variation in Fx, Fs, and total lipids of six brown algae [S. horneri, C. hakodatensis, Sargassum fusiforme (Harv.) Setch., Sargassum thunbergii (Mertens ex Roth) Kuntze, Analipus japonicus (Harv.) M. J. Wynne, and Melanosiphon intestinalis (D. A. Saunders) M. J. Wynne] indicated that these functional lipid components reached maximum during the period between January and March. The functional lipid components present in these seaweeds have the potential for application as nutraceuticals and novel functional ingredients after their recovery.