Laurencia viridis

In 1996, Norte and co-workers elucidated the structures of two new antitumor polyoxygenated squalene derivatives that were isolated from the acetone extracts of Laurencia viridis [9]. Isodehydrothyrsiferol [12, Fig. (3)] possesses an appended tetrahydropyran unit instead of the common tetrahydrofuran moiety observed in previous chemical structures. 

Among the marine natural products shown in Fig. (4), predehydrovenustatriol acetate (16) presents an attractive structural feature in regards to its biogenesis. The absence of the A-ring and the presence of the trisubstituted double bond between C2 and C3 points to a step-wise biosynthetic pathway this subject is discussed in the next section of this Chapter. Laurencia viridis has also been the source of thyrsenol A (19) and thyrsenol B [20, Fig. (5)]. Both of these compounds display an unusual enol ether moiety in the C-ring [11]. 

Vhc and /hh couplings have been a useful tool in determination of the structures of three new cytotoxic oxasqualenoids isolated by Cen-Pacheco et al from the red alga Laurencia viridis, 15-dehydroxythyrsenol A, prethyrsenol A and 13-hydroxyprethyrsenol A. 

Laurencia viridis, has exhibited promising cytotoxic activity. Therefore, the cytotoxic effect of DT on human estrogen receptor ER and ER" breast cancer cell lines was studied in a preclini-cal pharmacological evaluation. Although it was... 

The application of /-based analysis to either sp quaternary carbon centres or to consecutive methylene units, has been reported by Cen-Pacheco et for a highly flexible natural product, nivariol, a new pentacyclic polyether isolated from a Macaronesian endemic species of Laurencia Viridis. The obtained results allowed the authors to support a DFT-NMR-predicted stereostructure. Further examples of application of a /-based configuration analysis by the use of long-range couplings... 

Viridiol A Laurencia viridis Norte, Souto, and Fernandez, 1996... 

Some other structures related to the previous ones were isolated from Laurencia viridis (Fernandez et al., 2000 Souto et al, 2002). 

---