This bilateral project with scientists at Osaka University is aimed to  achieve long-term goals of sustainable and efficient use of plant resources in Vietnam. Phase 1 of the project focused on mangrove species of Avicennia genus and Excoecaria. Main compounds from collected plant samples are isolated, structural characterized, and  preliminary evaluated with some biological activities. In parallel, the genes coding for key enzymes (P450 enzymes) in terpenoid biosynthesis were isolated for developing potential terpenoids in yeast cells. During project, ehancement in research for members will be peformed.

Researchand application: From aerial part samples of Excoecaria agallocha species, 05 compounds were isolated and structural characterized. Among them, two compounds are new compounds and belong to diterpenoid group: 3β,20-epoxy-3α,6α,17-trihydroxy-18-nor-beyer-15-ene and 3β,20-epoxy-3,17,18-trihydroxy-beyer-15-ene. From aerial part samples of Avicennia marina species, 02 compounds were isolated and structurally characterized: acteoside and isoacteoside. The transcriptome sequence of A. marina leaves was identified and registed at  DDBJ gene bank with the accession number of DRA006410. Five gene fragments encoding P450 cytochrome enzymes were isolated from A. marina leaves (gene ID at DDBJ: LC325358-LC325362). Functional characterization of enzymes from those genes indicated that 02 enzymes played roles in biosynthesis of important triterpenoids such as  β-amyrin, α-amyrin, ursolic acid, erythrodiol, uvaol, betulin, lupeol, betulinic acid, oleanolic acid, maslinic acid and corosolic acid. The presence of these triterpenoids was confirmed by GC-MS analysis of A. marina leave extracts.  It is noted that three compounds, oleanolic acid, maslinic acid and corosolic acid are firstly recorded in  A. marina species.

Publication: 02 SCIE paper was published (Phytochemisty Letters, Plant Biotechnology Journal) and 01 scientific paper was published (Vietnam Journal of Chemistry Journal).

Education and training: In frame of the project, 06 researchers visited Osaka Universtiy for scientific training (1 month/member) and 03 delegations of Japanese researchers visited VAST for discussion.

- Isolation and characterization of 02 new compounds (3β,20-epoxy-3α,6α,17-trihydroxy-18-nor-beyer-15-ene và 3β,20-epoxy-3,17,18-trihydroxy-beyer-15-ene) from the mangrove species E. agallocha in Vietnam
- Identifying and analysing the RNA-sequences (accession number at DDBJ: DRA006410) from A. marina leaves.
-  Isolation of 5 gene fragments encoding P450 enzyme from A. marina leaves. Among them 02 genes were functional chareacterized in  triterpenoid biosyntheisis. 03 triterpenoid compounds: oleanolic acid, maslinic acid and corosolic acid are firstly recorded from A. marina species

- Publications: 02 SCIE papers and 01 national paper.
•    Excoecarins L and O from the mangrove plant Excoecaria agallocha L. Nguyen Van Thanh, Lai Hop Hieu, Phan Thi Thanh Huong, Le Thi Vien, Tran My Linh, Nguyen The Cuong, Nguyen Xuan Cuong, Nguyen Hoai Nam, Ngo Dai Quang, Chau Van Minh. Phytochemistry Letter (2018), Vol. 25, 52-55. ISSN 1874-3900.
•    Phenolic compounds isolated from the mangrove plant Avicennia marina (Forsk.) Vierh. Nguyen Van Thanh, Pham Thi Mai Huong, Le Viet Lan Huong, Tran Thu Huong, Tran My Linh, Nguyen Xuan Cuong, Nguyen Hoai Nam, Chau Van Minh. Vietnam Journal of Chemistry (2017), 55(5E3, 4) 521-525. ISSN 0866-7144.
•    Transcriptome sequencing and identification of cytochrome P450 monooxygenases involved in the biosynthesis of maslinic acid and corosolic acid in Avicennia marina. Nakamura Mitsuki, Tran My Linh, Le Quynh Lien, Suzuki Hayato, Nguyen Chi Mai, Vu Huong Giang, Tamura Keita, Nguyen Van Thanh, Suzuki Hideyuki, Misaki Ryo, Muranaka Toshiya, Ninh Khac Ban, Fujiyama Kazuhito, Seki Hikaru. Plant Biotechnology, 2018, Vol 35, 1-8. ISSN 1342-4580.

Conclusion: Chemical analysis of two mangrove species collected in Vietnam revealed that 03 compounds and 02 new compounds were isolated and characterized from E. agallocha,   02 compounds were isolated from A. marina. For isolation of key genes involved in terpenoid biosynthesis of A. marina, 05 gene fragments encoding P450 enzymes were successfully identified from leave samples. Among them, 02 genes were functionally characterized as enzymes involved in triterpenoid biosynthesis of A. marina leaves.
Suggestion:
- Further investigation can be concentrated on application of the isolated P450 genes in efficient expression systems for producing value triterpenoids.
-Enhancement of research collaboration between Institute of Marine Biochemistry, Vietnam Academy of Science and Technology and Osaka University.