Selecting Australian marine macroalgae based on the fatty acid composition and anti-inflammatory activity

Abstract

Increasingly, macroalgae are being recognised as a growth opportunity for functional foods and nutritional security in the future. Dominating traits of interest are metabolites that function as anti-inflammatories and are antiproliferative. However, seaweeds from the northern hemisphere dominate this field of research. Australia has a unique flora of macroalgae, and it is poorly understood which species should be targeted for cultivation towards food and health markets. Here, six Australian marine macroalgae were selected for screening of one anti-inflammatory group; n-3 polyunsaturated fatty acids (PUFA). PUFA profiles were determined using gas chromatography-mass spectrometry and multivariate analysis. Thirty-one fatty acids (FA) were identified across the six macroalgal species with C16:0 the dominant FA in all samples, variations across taxa in the saturated FA C10:0, C14:0, C16:0, C18:0 and C20:0 and variations in monounsaturated FA attributed to C16:1 n-7 and C18:1 n-9. For PUFA profiles, all six species had significantly different n-6/n-3 ratios, while the green seaweed Ulva species possessed the lowest n-6/n-3 ratio of 0.4, along with a 2-fold higher C18:3 n-3 to C18:2 n-6 content. Ulva sp. was the only species that contained docosahexaenoic acid. Extracts of both the Ulva sp. and Hormosira banksii showed selective cytotoxicity towards a human pancreatic cancer cell line, while the nonpolar extracts of all six algae species strongly inhibited production of the inflammatory-mediator nitric oxide. Abstract Increasingly macroalgae are being recognized as a growth opportunity for functional foods and nutritional security in the future. Dominating traits of interest are metabolites that function as anti-inflammatories and are antiproliferative. However seaweeds cultivated in the northern hemisphere dominate this field of research. Australia has a unique flora of macroalgae and it is poorly understood which species should be targeted for cultivation towards food and health markets. Herein, six Australian marine macroalgae were selected for screening of one antiinflammatory group; n-3 polyunsaturated fatty acids (PUFA). PUFA profiles were determined using gas chromatography -mass spectrometry and multivariate analysis. Thirty-one fatty acids (FA) were identified across the six macroalgal species with C16:0 the dominant FA in all samples, variations across taxa in the saturated FA C10:0, C14:0, C16:0, C18:0 and C20:0 and variations in monounsaturated FA attributed to C16:1 n-7 and C18:1 n-9. For PUFA profiles, all six species had significantly different n-6/n-3 ratios, while the green seaweed Ulva sp. possessed the lowest n-6/n-3 ratio of 0.4, along with a 2-fold higher C18:3 n-3 to C18:2 n-6 content. Ulva sp. was the only species that contained docosahexaenoic acid. Extracts of both the Ulva sp. and H. banksii showed selective cytotoxicity towards a human pancreatic cancer cell line, while the non-polar extracts of all six algal species strongly inhibited production of the inflammatory-mediator nitric ...

Algae as nutritional and functional food sources: revisiting our understanding

“…Several recent studies analyzed the constituent fatty acids of large numbers of red, brown, and green macroalgae from polar (Graeve et al 2002 , 20 species), temperate (Schmid et al 2014 , 16 species; McCauley et al 2015 , 10 species), and tropical (Kumari et al 2010 , 27 species; Kumar et al 2011 , 22 species) habitats, and, despite some species variability, red (Rhodophyta) and brown (Phaeophyceae) macroalgae had a high proportion of total FAs in EPA and arachidonic acid across latitudes, whereas the green (Chlorophyta) algae had low EPA (as % of total FA) but some DHA, and, were enriched in C18 LC PUFA. Phytoplankton contain more PUFA, as expected, when grown at low temperature (e.g., DHA in Crypthecodinium , Jiang and Chen 2000 ), and higher temperatures good for maximal biomass production can be lowered for as little as 12 h to induce maximal EPA content in the diatom Phaeodactylum (Jiang and Gao 2004 ).…”

Anti-inflammation effects of 8-oxo-9-octadecenoic acid isolated from Undaria peterseniana in lipopolysaccharide-stimulated macrophage cells

“…These compounds include fucoxanthin isolated from brown algae, dieckol isolated from Ecklonia cava , and polyphenolics isolated from Saccharina japonica . In the same studies, fatty acids derived from the seaweeds were also shown to have anti-inflammatory effects by reducing cytokine production via inhibiting MAPK pathways in macrophages (Robertson et al, 2015[ 34 ]; McCauley et al, 2015[ 29 ]). In our present study, similar results were obtained, with OOA significantly inhibiting the LPS activation of ERK and JNK pathway, which suggests that OOA is at least partly responsible for the anti-inflammatory effects previously observed.…”

Application of Glyceroglycolipids, Photosynthetic Pigments and Extracts of Brown Algae for Suppression ROS

“…As shown in several studies, the activity of the lipid extracts depends on the composition and ratio of fatty acids in them [23] [34]. It is believe, that a low n − 6/n − 3 ratio may be one of the factors influencing their anti-inflammatory properties [23].…”

“…As shown in several studies, the activity of the lipid extracts depends on the composition and ratio of fatty acids in them [23] [34]. It is believe, that a low n − 6/n − 3 ratio may be one of the factors influencing their anti-inflammatory properties [23]. These assumptions were based on experimental studies, which showed that incorporation of n − 3 PUFA modifies inflammatory and immune reactions, making n − 3 PUFA potential therapeutic agents for inflammatory and autoimmune diseases.…”

“…The methanol extract and their ethyl acetate and dichloromethane fractions of Saccharina japonica demonstrated the high inhibition of LPS-induced NO production in RAW 264.7 macrophage cells [22]. Investigation extracts of four species of brown algae Ecklonia radiata, Hormosira banksii, Phyllospora comosa and Myriogloea sciurus shown that nonpolar lipid-rich dichloromethane extracts of these algae had greatest anti-inflammatory activity (via inhibition of nitric oxide), compared with intermediate polarity ethyl acetate extracts and with the lowest activity observed in the polar butanol extracts [23]. Methanol extract and its hexane and chloroform fractions of brown seaweed Spatoglossum schroederi showed anti-inflammatory effect, which may be related to the presence of flavonoids [24].…”