Biotechnology and Bioinformatics (1+1)

5.1.9. Tunicates

Rinehart et al. (1981) have described antiviral and antitumor depsipeptides from a Caribbean tunicate.

• The extracts prepared from the sea squirt of the family Didemnidae, inhibit growth of DNA and RNA viruses , as well as L1210 leukemic cells.
• The tunicate of the Trididemnum genus, when extracted with methanol-tolulene (3:1), showed activity against herpes simplex virus, type I, grown in CV-1 cells (monkey kidney tissue), indicating that the extract inhibited the growth of the virus.
• This antiviral activity may also involve antitumor activity. When tested against other viruses, essentially all extracts of the tunicate collected at a number of sites showed activity in inhibiting both RNA and DNA viruses. The suggestion that the extracts might also have antitumor properties was evidenced from their high potency against L1210 murine leukemic cells.
• Didemnin B, a cyclic antiproliferative depsipeptide isolated from the Caribbean tunicate Trididemnum solidum, was the first marine natural product to enter clinical trial as an antitumor agent. It showed antitumor activity against a variety of models and has been investigated in phase II clinical trials for the treatment of breast, ovarian, cervical, myeloma, glioblastoma/astrocytoma, and lung cancers. Didemnin B inhibits the synthesis of RNA, DNA, and protein s and binds noncompetitively to palmitoyl protein thioesterase.