title: Extraction and Identification of Phlorotannins from the Brown Alga, Sargassum fusiforme (Harvey) Setchell.
abstract: Phlorotannins are a group of complex polymers of phloroglucinol (1,3,5-trihydroxybenzene), which are unique compounds from marine brown algae. In our present study, a procedure for extraction and enrichment of phlorotannins fromS. fusiformewith highly antioxidant potentials was established. After comparison of different extraction methods, the optimal extraction conditions were established as follows. The freeze-dried seaweed powder was extracted with 30% ethanol-water solvent with a solid/liquid ratio of 1:5 at temperature of 25 °C for 30 min. After extraction, the phlorotannins were fractioned by different solvents, among which the ethyl acetate fraction exhibited both the highest total phlorotannin content (88.48 ± 0.30 mg PGE/100 mg extract) and the highest antioxidant activities. The extracts obtained from these locations were further purified and characterized using a modified UHPLC-QQQ-MS method. Compounds with 42 different molecular weights were detected and tentatively identified, among which the fuhalol-type phlorotannins were the dominant compounds, followed by phlorethols and fucophlorethols with diverse degree of polymerization. Eckol-type phlorotannins including some newly discovered carmalol derivatives were detected inSargassumspecies for the first time. Our study not only described the complex phlorotannins composition inS. fusiforme, but also highlighted the challenges involved in structural elucidation of these compounds.
authors.affiliation: College of Food Science & Engineering, Ocean University of China, Qingdao 266000, China. Sakura_yj@163.com.
authors.forename: Yajing
authors.initials: Y
authors.lastname: Li
authors.affiliation: College of Food Science & Engineering, Ocean University of China, Qingdao 266000, China. xiaotingfu@ouc.edu.cn.
authors.forename: Xiaoting
authors.initials: X
authors.lastname: Fu
authors.affiliation: Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China. dlduan@qdio.ac.cn.|State Key Lab of Seaweed Bioactive Substances, Qingdao 266000, China. dlduan@qdio.ac.cn.
authors.forename: Delin
authors.initials: D
authors.lastname: Duan
authors.affiliation: Shandong Haizhibao Ocean Science and Technology Co., Ltd., Qingdao 266000, China. xyliu@chengshan.com.
authors.forename: Xiaoyong
authors.initials: X
authors.lastname: Liu
authors.affiliation: College of Food Science & Engineering, Ocean University of China, Qingdao 266000, China. xujia@ouc.edu.cn.
authors.forename: Jiachao
authors.initials: J
authors.lastname: Xu
authors.affiliation: College of Food Science & Engineering, Ocean University of China, Qingdao 266000, China. xingao@ouc.edu.cn.
authors.forename: Xin
authors.initials: X
authors.lastname: Gao
mesh_terms: D000975:Antioxidants / Q000737:chemistry; D001688:Biological Products / Q000737:chemistry*; D008970:Molecular Weight; D000459:Phaeophyceae / Q000737:chemistry*; D010696:Phloroglucinol / Q000737:chemistry; D058105:Polymerization; D011108:Polymers / Q000737:chemistry; D044647:Sargassum / Q000737:chemistry*; D012624:Seaweed / Q000737:chemistry; D013634:Tannins / Q000737:chemistry*
chemical_list: D000975:Antioxidants; D001688:Biological Products; D011108:Polymers; D013634:Tannins; D010696:Phloroglucinol
keywords: Sargassum fusiforme; UHPLC-DAD-ESI-MS; brown alga; extraction method; identification; phlorotannins; polyphenol