The objective of the project was to study metabolites (water-soluble polysaccharides, polysaccharide-metabolizing enzymes) from seaweeds, marine invertebrates and microorganisms of the Vietnamese Sea.

- This study have studied the structural characteristics of fucoidan extracted from two new species of brown seaweed, S. duplicatum and S. feldmannii, and provided the data on the antitumor activity of fucoidan fractions extracted from these two seaweed species. Among them, the structure of SfF2 fucoidan fraction of S. feldmannii was determined.
- For sulfated polysaccharides from sea cucumber, the chemical composition of 03 sea cucumber species, S. horrens, H. spinifera and H. astra collected in Vietnam Sea were analyzed. The basical structure of PS form S. horrens and H. astra were established.
- For polysaccharide metabolizing enzymes from marine invertebrates, the fucoidanase from V. flavum cleaved 1→3 links in the backbond of PS extracted from S. variegaatus sea cucumber has been found.
- For polysaccharide-metabolizing enzymes from marine microorganisms, 87 strains of marine bacteria were isolated, among them, 05 potential strains of marine bacteria were able to produce polysaccharide-metabolizing enzymes.

- The structural characteristics and data on antitumor activity of fucoidan extracted from two previously unstudied brown seaweed species, S. duplicatum and S. feldmannii have been found.
- An enzyme from the marine invertebrates V. flavum has been found to be able to cleave (1→3) linkages of PS extracted from two sea cucumber species Holothuria spinifera and Stichopus variegatus collected in Vietnam sea.
- 02 Masters in Chemistry were trained and 01 PhD student was supported data.

- Publications:
SCIE Journal: 01
- Roza V. Usoltseva, Stanislav D. Anastyuk, Valeriy V. Surits, Natalia M. Shevchenko, Pham Duc Thinh, Pavel A. Zadorozhny, Svetlana P. Ermakova 2019, “Comparison of structure and in vitro anticancer activity of native and modified fucoidans from Sargassum feldmannii and S. duplicatum”, International Journal of Biological Macromolecules, Vol.124: 220 – 228.
VAST2 Journals: 03
- Pham Duc Thinh, Tran Thanh Huyen, Tran Thi Thanh Van, Cao Thi Thuy Hang, Dinh Thanh Trung, and Pham Trung San, 2019, “Extraction and structural characteristic of polysaccharide sulfate from sea cucumber Holothuria spinifera”, Vietnam Journal of Chemistry, 57(4E1,2):108-13.
- Cao Thi Thuy Hang, Vo Thi Dieu Trang, Đinh Thanh Trung, Tran Thi Thanh Van, Nguyen Xuan Vien, Huynh Hoang Nhu Khanh, Pham Đuc Thinh, 2020, “The potential producing brown seaweed polysaccharide-modifying enzymes of marine bacteria isolated from the collected samples at Vietnam sea in the journey of the Akademik Oparin vessel in 2018”, Vietnam Journal of Marine Science and Technology, 20(4B) 345-345.
- Huynh Hoang Nhu Khanh, Vo Thi Dieu Trang, Pham Duc Thinh, Pham Trung San, 2019, “Catalytic conditions of fucoidanase from Vasticardium flavum”, Vietnam Journal of Science and Technology 57 (1) 28-37
Education: The project has supported the training of 02 Masters in Chemistry and provide data for 01 PhD student.

Conclusion: This project was carried out in 2018-2021 and completed the research contents on schedule.
Suggestion: It is necessary to continue to expand the research of biologically active substances from Vietnamese marine organisms in order to exploit and rationally use the natural resources.