Seaweed is more than the wrap that keeps rice together in sushi. Seaweed biomass is already used for a wide range of other products in food, including stabilising agents. Biorefineries with seaweed as feedstock are attracting worldwide interest and include low-volume, high value-added products and vice versa. Scientific research on bioactive compounds in seaweed usually takes place on just a few species and compounds. This paper reviews worldwide research on bioactive compounds, mainly of nine genera or species of seaweed, which are also available in European temperate Atlantic waters, i.e. Laminaria sp., Fucus sp., Ascophyllum nodosum, Chondrus crispus, Porphyra sp., Ulva sp., Sargassum sp., Gracilaria sp. and Palmaria palmata. In addition, Undaria pinnatifida is included in this review as this is globally one of the most commonly produced, investigated and available species. Fewer examples of other species abundant worldwide have also been included. This review will supply fundamental information for biorefineries in Atlantic Europe using seaweed as feedstock. Preliminary selection of one or several candidate seaweed species will be possible based on the summary tables and previous research described in this review. This applies either to the choice of high value-added bioactive products to be exploited in an available species or to the choice of seaweed species when a bioactive compound is desired. Data are presented in tables with species, effect and test organism (if present) with examples of uses to enhance comparisons. In addition, scientific experiments performed on seaweed used as animal feed are presented, and EU, US and Japanese legislation on functional foods is reviewed.

Bioactive compounds in seaweed: functional food applications and legislation

In vitro antioxidant properties of crude extracts and compounds from brown algae

Towards a better understanding of medicinal uses of the brown seaweed Sargassum in Traditional Chinese Medicine: a phytochemical and pharmacological review.

Extracts from 48 marine macroalgae species (17 Chlorophyta, 8 Phaeophyta and 23 Rhodophyta) from the coasts of Yucatan and Quintana Roo (Mexico) were evaluated for antioxidant activity. The antioxidant activity was measured with the DPPH (2,2-diphenyl-1-picrylhydra- syl) method, and the phenolic content of each extract were also evaluated. All species exhibited a DPPH radical scavenging activity, and three species (Avrainvillea long- icaulis, Chondria baileyana and Lobophora variegata) demonstrated great antioxidant potential with very low oxidation index EC50 (1.44±0.01, 2.84±0.07 and 0.32± 0.01 mg mL �1 , respectively), significantly equivalent to EC50 of some commercial antioxidants such as α-tocoph- erol, ascorbic acid, BHA and BHT. Moreover, extracts of the most active species exhibited reducing activities, superoxide anion radical scavenging and inhibition of lipid peroxidation. These results suggest that some macroalgae from the Yucatan peninsula have a great antioxidant potential which could be considered for future applications in medicine, food production or cosmetic industry.

Antioxidant activities in tropical marine macroalgae from the Yucatan Peninsula, Mexico

The Recent Impact of Solid-Phase Synthesis on Medicinally Relevant Benzoannelated Nitrogen Heterocycles

Essential oil from the leaves of Tateyamasugi (Cryptomeria japonica) exhibited strong inhibitory activity on ulceration induced by HCl/ethanol, HCl/aspirin, water-immersion stress and pylorus-ligation. We separated the antiulcer compounds from cedar essential oil by use of distillation and chromatography. As a result, terpinen-4-ol, a monoterpene, and elemol, a sesquiterpene, were isolated as active compounds. The antiulcer activity of the former was more potent than that of the latter. Terpinen-4-ol was a mixture of optical isomers and each possessed potent antiulcer activity. Secretion of gastric juice and output of acid and pepsin activity were lowered by terpinen-4-ol. These results suggest that terpinen-4-ol isolated from cedar essential oil could be a valuable antiulcer agent.

Isolation of the antiulcer compound in essential oil from the leaves of Cryptomeria japonica.

Martefragin A (1), a novel indole alkaloid, was isolated from a red alga, Martensia fragilis, by repeated column chromatography. The structure of 1 was elucidated on the basis of spectral analysis of its methyl ester (2), including 1H- and 13C-NMR, 1H-1H correlation spectroscopy (COSY), and 13-1H COSY. A single crystal X-ray analysis of the hydrochloride of 1 confirmed the assignment. Martefragin A (1) showed inhibitory activity on NADPH-dependent lipid peroxidation in rat liver microsomes. The IC50 values of 1, α-tocopherol and ascorbic acid were 2.8, 87 and 200 μM, respectively.

Martefragin A, a Novel Indole Alkaloid Isolated from Red Alga, Inhibits Lipid Peroxidation.

Several extracts from marine brown alga Sargassum micracanthum (Kuetzing) Endlicher were screened for their inhibitory activity on lipid peroxidation. In an in vitro study, methanol extract (Sm-M), chloroform/ methanol (3:1) extract and ethyl acetate fraction of Sm-M inhibited lipid peroxidation in rat liver homogenates. The IC(50) values were 0.70, 0.70 and 0.37 micro g/mL, respectively. These inhibitions were stronger than vitamin C and E. These extracts showed reductive activity on DPPH, the IC(50) values were 34, 37 and 11 micro g/mL, respectively. In an in vivo study, Sm-M had the effect on CCl4 induced liver injury in rats and Sm-M (120-1200 mg/kg, p.o.) lowered dose-dependently the level of lipid peroxidation in liver.

Inhibitory activity on lipid peroxidation of extracts from marine brown alga.

PROBLEM TO BE SOLVED: To provide a method for culturing a marine microalga having an excellent hyaluronidase inhibitory activity and high safety and to obtain a hyaluronidase inhibitor and a medicinal agent, a cosmetic and a food comprising an extract thereof as an active ingredient. SOLUTION: This hyaluronidase inhibitor comprises an extract from a marine microalga isolated from seawater, especially deep water as an active ingredient and the extract is an extract from a diatom of the genus Navicula. The extract from the marine microalga is an ethanol-insoluble fraction extracted therefrom with hot water. The hyaluronidase inhibitor has antiinflammatory actions or antiallergic actions.

Method for culturing marine microalga, hyaluronidase inhibitor, medicinal agent, cosmetic and food comprising its extract as active ingredient

Novel stereoisomeric indole compounds represented by general formula (1), wherein Y is (2) or (3), (wherein * represents the position of an asymmetric carbon atom), [wherein X is C1-C5 alkyl optionally substituted with OH, carboxyl, amino, methylthio, mercapto, guanidyl, imidazolyl or benzyl; and R1 and R2 are each independently H, alkyl, aralkyl, cycloalkyl or aryl]; and R is H, alkyl, aralkyl, cycloalkyl, aryl, monovalent metal, amine or ammonium). The compounds can be prepared by condensing tryptophan with a stereoisomeric α-amino acid or carboxylic acid to form an amide and subjecting the amide to oxidative cyclization to form an oxazole ring at once. The compounds exhibit physiological activities such as inhibitory activity against lipid peroxidation, and can be therefore utilized in the form of lipid peroxidation inhibitors containing the same as the active ingredient.

Chika Hasegawa

Papers

Isolation of the antiulcer compound in essential oil from the leaves of Cryptomeria japonica.

Martefragin A, a Novel Indole Alkaloid Isolated from Red Alga, Inhibits Lipid Peroxidation.

Inhibitory activity on lipid peroxidation of extracts from marine brown alga.

Method for culturing marine microalga, hyaluronidase inhibitor, medicinal agent, cosmetic and food comprising its extract as active ingredient

Stereoisomeric indole compounds, process for the preparation of the same, and use thereof