SEAWEED EXTRACTS AS A POTENTIAL TOOL FOR THE ATTENUATION OF OXIDATIVE DAMAGE IN OBESITY‐RELATED PATHOLOGIES 1

Recent studies suggest that seaweed extracts are a significant source of bioactive compounds comparable to the dietary phytochemicals such as onion and tea extracts. The exploration of natural antioxidants that attenuate oxidative damage is important for developing strategies to treat obesity‐related pathologies. The objective of this study was to screen the effects of seaweed extracts of 49 species on adipocyte differentiation and reactive oxygen species (ROS) production during the adipogenesis in 3T3‐L1 adipocytes, and to investigate their total phenol contents and 2,2‐diphenyl‐1‐picrylhydrazyl (DPPH) radical scavenging activities. Our results show that high total phenol contents were observed in the extracts of Ecklonia cava (see Table 1 for taxonomic authors) (681.1 ± 16.0 μg gallic acid equivalents [GAE] · g −1 ), Dictyopteris undulata (641.3 ± 70.7 μg GAE · g −1 ), and Laurencia intermedia (560.9 ± 48.1 μg GAE · g −1 ). In addition, DPPH radical scavenging activities were markedly higher in Sargassum macrocarpum (60.2%), Polysiphonia morrowii (55.0%), and Ishige okamurae (52.9%) than those of other seaweed extracts ( P  <   0.05). Moreover, treatment with several seaweed extracts including D. undulata , Sargassum micracanthum , Chondrus ocellatus , Gelidium amansii , Gracilaria verrucosa , and Grateloupia lanceolata significantly inhibited adipocyte differentiation and ROS production during differentiation of 3T3‐L1 preadipocytes. Furthermore, the production of ROS was positively correlated with lipid accumulation ( R 2  = 0.8149). According to these preliminary results, some of the seaweed extracts can inhibit ROS generation, which may protect against oxidative stress that is linked to obesity. Further studies are required to determine the molecular mechanism between the verified seaweeds and ROS, and the resulting effects on obesity. 1  List of Korean seaweed extracts of 49 species evaluated in this experiment.Type No. Scientific name Collection time TP 1 (μg GAE · g −1 )Brown macroalgae SE‐1 Chondracanthus tenellus (Harv.) Hommers. April 27, 2006 112.8 ± 15.1 lmSE‐2 Colpomenia sinusa (F. C. Mertens ex Roth) Derbes et Solier in Castagne May 11, 2006 44.0 ± 4.1 opqrsSE‐3 Dictyopteris divaricata (Okamura) Okamura April 6, 2006 41.5 ± 5.6 pqrsSE‐4 Dictyopteris pacifica (Yendo) I. K. Hwang, H.‐S. Kim et W. J. Lee April 27, 2006 80.9 ± 8.3 mnoSE‐5 Dictyopteris prolifera (Okamura) Okamura November 26, 2007 48.4 ± 3.0 nopqrsSE‐6 Dictyopteris undulata Holmes July 28, 2007 641.3 ± 70.7 bSE‐7 Dictyota asiatica I. K. Hwang April 6, 2006 52.9 ± 7.6no nopqrSE‐8 Ecklonia cava Kjellm. October 22, 2006 681.1 ± 16.0 aSE‐9 Ecklonia stolonifera Okamura November 26, 2007 36.5 ± 3.4 pqrsSE‐10 Endarachne binghamiae J. Agardh March 10, 2006 50.4 ± 2.6 nopqrsSE‐11 Hizikia fusiformis (Harv.) Okamura July 23, 2006 16.4 ± 1.2 rsSE‐12 Hydroclathrus clathratus (C. Agardh) M. Howe May 11, 2006 18.1 ± 0.9 rsSE‐13 Ishige okamurae Yendo May 26, 2006 237.4 ± 1.6 hSE‐14 Lethesia difformis (L.) Aresch. May 11, 2006 11.2 ± 1.9 sSE‐15 Myelophycus simplex (Harv.) Papenf. April 27, 2006 39.5 ± 3.2 pqrsSE‐16 Padina arborescens Holmes July 29, 2007 172.9 ± 23.1 ijSE‐17 Sargassum fulvellum (Turner) C. Agardh April 27, 2006 119.1 ± 5.6 klSE‐18 Sargassum micracanthum (Kütz.) Endl. December 21, 2006 468.0 ± 22.7 eSE‐19 Sargassum patens C. Agardh January 21, 2007 41.5 ± 5.7 pqrsSE‐20 Sargassum confusum C. Agardh f. validum Yendo March 8, 2008 110.9 ± 3.5 lmSE‐21 Sargassum horneri (Turner) C. Agardh March 1, 2006 84.8 ± 9.4 lmnSE‐22 Sargassum macrocarpum C. Agardh January 21, 2007 353.9 ± 59.1 gSE‐23 Sargassum muticum (Yendo) Fensolt January 21, 2007 72.1 ± 14.9 nopSE‐24 Sargassum nipponium Yendo April 6, 2006 54.0 ± 3.5 nopqrSE‐25 Sargassum sagamianum Yendo March 8, 2008 41.0 ± 6.7 pqrsSE‐26 Sargassum thunbergii (Mertens ex Roth) Kuntze July 23, 2006 27.7 ± 0.8 qrsSE‐27 Scytosiphon gracilis Kogame May 26, 2006 30.2 ± 5.6 qrsSE‐28 Scytosiphon lomentaria (Lyngb.) Link May 11, 2006 66.5 ± 8.9 nopqRed macroalgae SE‐29 Bonnemaisonia hamifera Har. April 27, 2006 44.1 ± 2.3 opqrsSE‐30 Callophyllis crispata Okamura May 11, 2006 37.6 ± 12.6 pqrsSE‐31 Chondria crassicaulis Harv. May 11, 2006 45.4 ± 4.4 opqrsSE‐32 Chondrus crispus Stackh. May 26, 2006 40.7 ± 8.0 pqrsSE‐33 Chondrus ocellatus Holmes May 11, 2006 47.2 ± 1.7 nopqrsSE‐34 Gelidium amansii (J. V. Lamour.) J. V. Lamour. April 27, 2006 525.3 ± 35.9 dSE‐35 Gloioperltis furcata (Postels et Rupr.) J. Agardh May 26, 2006 147.7 ± 6.4 jkSE‐36 Gloioperltis complanta (Harv.) Yamada May 26, 2006 58.2 ± 6.4 nopqSE‐37 Gracilaria verrucosa (Hudson) Papenf. March 6, 2008 55.1 ± 7.5 nopqrSE‐38 Grateloupia elliptica Holmes May 26, 2006 154.4 ± 12.9 jSE‐39 Grateloupia filicina (J. V. Lamour.) C. Agardh May 11, 2006 38.2 ± 2.2 pqrsSE‐40 Grateloupia lanceolata (Okamura) Kawag. July 23, 2006 32.7 ± 3.0 pqrsSE‐41 Laurencia intermedia J. V. Lamour. May 11, 2006 560.9 ± 48.1 cSE‐42 Laurencia intricata J. V. Lamour. April 27, 2006 35.4 ± 4.0 pqrsSE‐43 Laurencia okamurae Yamada May 11, 2006 193.2 ± 41.9 iSE‐44 Lomentaria hakodatensis Yendo April 27, 2006 165.2 ± 15.1 ijSE‐45 Polyopes affinis (Harv.) Kawag. et H.‐W. Wang May 26, 2006 42.9 ± 2.3 opqrsSE‐46 Polysiphonia morrowii Harv. May 11, 2006 392.4 ± 40.3 fSE‐47 Prionitis cornea (Okamura) E. Y. Dawson October 22, 2006 47.9 ± 3.6 nopqrsGreen macroalgae SE‐48 Enteromorpha prolifera (O. F. Müll.) J. Agardh March 26, 2006 42.0 ± 5.3 pqrsSE‐49 Ulva pertusa Kjellm. April 27, 2006 48.3 ± 3.8 nopqrsGAE, gallic acid equivalents; SE, seaweed extracts.1 TP, total phenol content is micrograms of total phenol contents per gram of seaweed extract based on gallic acid as standard. The values are means ± SD from three replications.a–s Means in the same column not sharing a common letter are significantly different ( P  <   0.05) by Duncan’s multiple test.