Dang Diem Hong1, 2, Le Thi Thom1, Nguyen Cam Ha1, Luu Thi Tam1, Ngo Thi Hoai Thu1, Hoang Thi Minh Hien1, Tran Mai Duc2, Nguyen Van Tru1, Nguyen Thi Minh Hang3
1 Institute of Biotechnology, Vietnam Academy of Science and Technology, Hanoi, Vietnam
2 Graduate University of Science and technology, Vietnam Academy of Science and Technology, Hanoi, Vietnam
3Institute of Marine Biochemistry, Vietnam Academy of Science and Technology, Hanoi, Vietnam
Vietnam is very diverse and rich in seaweed/macroalgae species. The major economically important seaweed groups can be used for food and feed (humans and animals), industrial materials, traditional medicine, biofertilizers as well as biofuel and new material. The present study aims to optimize the extraction conditions and evaluate the antioxidant and neuroprotective activities of 60 compounds and extracts obtained from 30 seaweed species belonging to Caulerpa, Sargassum, Gracilaria, Ulva, Kappaphycus and Eucheuma genera collecting from NinhThuan, KienGiang, Ba Ria-VungTau and KhanhHoa provinces of Vietnam from Jan to May, 2022. The survey conditions of seaweed biomass extraction include different solvents (as ethanol 70%, ethanol 96%, n-hexane, ethyl acetate and water), raw seaweed biomass: solvent ratio (as from 1:3 to 1:8), extraction time (1-10 h) and with or without the ultrasound-assisted extraction (ultrasound power 80W, 1 h, 4.7 KHz). Six bioactive seaweed-derived compounds and extracts per 60 compounds/extracts isolated were screened by evaluating of antioxidant activity using 2,2-diphenyl-1-picrylhydrazyl radical scavenging (DPPH) assay (with IC50 £ 5 mg/mL for extracts and IC50 £ 200 mM for compounds); acetylcholinesterase inhibitory property using acetylcholinesterase inhibitor screening KIT (with IC50 values < 100 µg/mL for extracts and IC50 £ 100 mM for compounds) when compared to standard drug galantamine (IC50 value < 6 µg/mL). On the other hand, potential neuroprotective activity against amyloid beta (Aβ25-35) induced neurotoxicity in C6 cells was conducted. Overall, the outcome of the study signifies the neuroprotective effect of 6 compounds and extracts from 30 seaweed species of Vietnam.