[1] Bulgarian Acad Sci, Ctr Phytochem, Inst Organ Chem, Acad G Bonchev Str,Bl 9, Sofia 1113, Bulgaria
[2] Vietnam Acad Sci & Technol, Inst Marine Biochem, Hanoi 10000, Vietnam
[3] Grad Univ Sci & Technol, Vietnam Acad Sci & Technol, Hanoi 10000, Vietnam
[4] Vietnam Acad Sci & Technol, Inst Ecol & Biol Resources, Hanoi 10000, Vietnam
[5] Quy Nhon Univ, Fac Nat Sci, Quy Nhon 55000, Vietnam