Laurencia specie

Fig. 5.12 Compounds 488-505, halogenated terpenes from Portieria and Laurencia species...

Fig. 5.14 Compounds 506-518, more terpenes from Laurencia species...

Irie, T., M. Suzuki, and T. Masamune Laurencin, a Constituent from Laurencia Species. Tetrahedron Letters 1965, 1091. 

An array of new and unusual halogenated terpenes have been isolated and characterized from Laurencia red algae [14], This genus is well known as a source of halogenated sesquiterpenes. New chamigrane-type derivatives were isolated from Laurencia species, some from Laurencia... 

Francisco MEY, Erickson KL (2001) Ma iliohydrin, a Cytotoxic Chamigrene Dibromohy-drin from a Philippine Laurencia Species. J Nat Prod 64 790... 

Vairappan CS, Suzuki M, Abe T, Masuda M (2001) Halogenated Metabolites with Antibacterial Activity from the Okinawan Laurencia Species. Phytochemistry 58 517... 

Suzuki M, Nakano S, Takahashi Y, Abe T, Masuda M (1999) Bisezakyne-A and -B, Halogenated C15 Acetogenins from a Japanese Laurencia Species. Phytochemistry 51 657... 

Perforatone (46) and perforenones A (47 R = OH) and B (47 R = Cl) have been discovered in the marine alga Laurencia perforata.78 It is suggested that (46) and (47) are formed from a chamigrene cation (48), and this hypothesis provides a full rationale for the biosynthesis of the wide variety of sesquiterpenoids that have been isolated from Laurencia species. 

The formation of halogenated sesquiterpenoids in Laurencia intricata has been the subject of speculation and the finding of a- and /3-snyderol (63) and (64) in several Laurencia species was held to support the involvement of a brominated monocyclofarnesol intermediate for chamigrane derivatives [c.g. elatol (65)]. The latter and caespitol (66) co-occur in L. obtusa and it was proposed that a bisabolonium ion (67) may be the common precursor for these two skeletal types. 

Laurencia species found off the coast of Australia and it may be of biosynthetic significance that the bromoeudesmane derivative (403) co-occurs with (404) (c/. Vol. 8, p. 101). A new component of the Hawaiian marine alga Laurencia nidifica has been identified as (-i-)-selina-4,7(l l)-diene (405) on the basis of spectroscopic evidence.Detailed chromatographic analysis of the sesquiterpenoid constituents of costus plant roots has revealed the presence of a-costol (406), y-costol (407), y-costal (408), and the elemene derivative (409). ... 

Neoconcinndiol hydroperoxide (9) is an unusual diterpenoid obtained from Laurencia species of red alga. The structure may arise through rearrangement and oxidation of a 3j8-bromoIabdane. Nivenolide (10) is a diterpenoid lactone. 

The red alga Laurencia produces an unusual group of bromine and chlorine-bearing ethers based upon an n-pentadecane skeleton, of probable fatty acid origin. Specific examples of the approximately 25 described substances are the halogenated ethers 8 and 9, isolated from L. glandulifera in Japan (Irie et al., 1965) and an undescribed Laurencia species from the Gulf of California, Mexico (Fenical et al., 1974). 

In contrast to the abundance of the sesquiterpenoids, the halogenated diterpenoids are rare compounds found only in some Laurencia species and in the Mediterranean alga Sphaerococcus coronopifolius (Fenical et al., 1976 Fattorusso et al., 1976). The diterpenoids concinndiol (33) (Sims et al., 1973) and iriediol (34) (Fenical et al., 1975) represent most diterpenoid skeletons in Laurencia, while the uncommon primary halide functionality of sphaerococcenol A (35) is unique to S. coronopifolius. The sole example of a halogenated triterpenoid is the squalene-derived compound 36 from the... 

DDT (trace A) and its metabolites DDE and DDD (trace B), and traces F and G are the commercial polychlorinated biphenyl (PCB) mixtures Arochlor 1242 (trace F) and Arochlor 1254 (trace G). As is illustrated, extracts of local Laurencia species (traces C and D), and the extract of a halogenating bacterium Chromobacterium sp. (trace E), contain compounds of similar retention time to DDT and its metabolites. Traces H and J were produced from extracts of Plocamium cartilagineum and Chondria californica, two locally abundant red algae, and trace I was produced from a species unidentified sponge of the genus Verongia. In this case mixtures of halogenated natural compounds fall within the limits of detectability of the PCBs. 

CisH BrjClOj, Mr 424.56, colorless cryst., mp. 165-167°C, [a]D -257.6° (CHCI,). The allene O. I was first isolated from the alga Laurencia obtusa but also occurs in other Laurencia species. It is accompanied by numerous other halogenated Cjj-Cjo fatty acid derivatives with antifungal activities. O. exists as the 3,13-dioxabicyclo[7.3.1]trideca-5,9-diene as a result of the formation of ether bridging bonds. 

Figure 31. Selected Structures of halogenated indole alkaloids alkaloids isolated from Laurencia species.

As a result of our studies on chemical constituents of marine plants and animals in 1 intertidal zone near Karachi, we have investigated red and brown algae and various mari animals. Laurencia pinnatifida belongs to the family Rhodomalaceae. Laurencia species i well known for the halogenated compounds of varied chemical structures and diverse biologi properties such as antimicrobial activity, cytotoxicity etc. We have isolated pinnatazs... 

Francisco, M.E.Y. and Erickson, K.L. (2001) Ma iliohydrin, a cytotoxic chamigrene dibro-mohydrin from a Philippine Laurencia species. J. Nat. Prod. 64, 790-791... 

Vairappan, C.S. et al. (2001) Antibacterial halogenated metabolites from the Malaysian Laurencia species. Phytochemistry. 58, 291-297... 

Since the 1980s, these brominated squalenoids have been identified in several other Laurencia species collected in all the world s oceans (Canary Islands, Japan, Vietnam),... 

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