- Isolation a large amount of the bioactive compound rivularin A.
- Discovery of bioactive compounds equivalent to rivularin A from the sea slug Aplysia sp. and the sea snail Monodonta labio (Linnaeus, 1758).
- Evaluation for the biological activities of isolated compounds and study the ability of rivularin A to kill cancer cells.

Theoretical results:
- Two sample of the sea slug Aplysia dactylomela were collected at Hon Me, Thanh Hoa, and at Nhat Le, Quang Binh. One sample of the sea snail Monodonta labio was collected at Lang Co, Thua Thien - Hue.
- Chemical study on the extract of the sea snail Monodonta labio resulted in the identification of 6 compounds, in which compound ML1 (rivularin A) was purified in large amount (100 mg). Two polibrominated bi-indole compounds (ML1 and ML7) exhibited cytotoxic activity on HepG2, DU145 and A549 cell lines, of which ML01 (at 10 µM) was found to be a inducer apoptosis in the human liver cancer cell HepG2.
- The investigation on the sea slug Aplysia dactylomela, collected from Quang Binh, led to the isolation and structural elucidation of nine compounds (ADR1 - ADR9). Among these metabolites, ADR1 and ADR2 were two new 10-bromo-chamigrane sesquiterpenes. The absolute configurations of ADR1 and ADR3 were determined by quantum chemical electronic circular dichroism (ECD) calculation. ADR2 was the first chamigrane sesquiterpenoid containing the B ring with two epoxide groups. The cytotoxicity study showed the cytotoxic effects for six compounds, in which ADR5 exhibited the strong activity against 4 cell lines MCF7, HepG2, Hela and A549 with IC50 in the range of 0.45 - 2.74 μM. Comparison of IC50 values showed that elatol (IC50 = 0.66 μM) inhibited the growth of HepG2 cell more strongly than rivularin A (IC50 = 7.74 μM).
- Three new sesquiterpenes, aplydactylonin A-C (AD1-AD3), were isolated from the sea slug Aplysia dactylomela, collected at Thanh Hoa province. The absolute configurations of compounds AD1 and AD3 were established by single crystal X-ray diffraction (X-ray) and ECD methods. Compound AD3 is a rare rearranged chamigrane sesquiterpene containing a 3,11-epoxy linkage. The cytotoxicity test results showed that compound AD2 was active on HepG2 and A549 cell lines with IC50 of 4.08 ± 0.63 and 12.33 ± 0.95 μM, respectively. In addition, compound AD2 (at 5 µM) was also shown to induce apoptosis in HepG2 cell, that was better than the apoptotic activity of rivularin A.  
Applied results: Compound ML1 (rivularin A) was obtained in large volume, which can be used for further studies on biological activity and pharmacology.

- Five new sesquiterpenes were isolated and identified from two samples of the sea hare Aplysia dactylomela collected in Quang Binh and Thanh Hoa.
- Nine compounds derived from the sea slug A. dactylomela and the sea snail M. labio were found to have cytotoxic activity. Among these compounds, elatol (ADR5), aplydactylonin B (AD2) and rivularin A (ML1) exhibited potent cytotoxic effects.
- Compounds aplydactylonin B (AD2) and rivularin A (ML1) were found to induce apoptosis in the cell HepG2 for the first time.

- Scientific papers in referred journals (list):
3.    Pham Thi Mai Huong, Nguyen Viet Phong, Nguyen Thi Huong, Duong Thu Trang, Do Thi Thao, Nguyen Xuan Cuong, Nguyen Hoai Nam, Nguyen Van Thanh*. “Aplydactylonins A-C, three new sesquiterpenes from the Vietnamese sea hare Aplysia dactylomela and their cytotoxicity”. Journal of Natural Medicines (2022) 76:210–219.
4.    Pham Thanh Binh, Duong Thu Trang, Nguyen Phuong Thao, Nguyen Chi Mai, Nguyen Xuan Cuong, Nguyen Hoai Nam, Nguyen Van Thanh*. “Structure elucidation of new brominated sesquiterpenes from the sea hare Aplysia dactylomela by experimental and DFT computational methods”. Journal of Molecular Structure 1259 (2022) 132744.
- Technological products (describe in details: technical characteristics, place):
The rivularin A (100 mg) and 17 pure compounds were kept at the department of Bioactive Natural Products, Institute of Marine Biochemistry.

The research group would like to make further studies on cytotoxic mechanisms of the new compound aplydactylonin B (AD2) and two known compunds, rivularin A (ML1) and elatol (ADR5). In addition, we would like to continue to investigate on new bioactive compounds from Vietnamese sea slug and sea snail.