Halogenated Metabolites from the New Okinawan Red AlgaLaurencia yonaguniensis

Abstract

A novel brominated diterpene based on the rare neoirieane skeleton, named neoirietetraol (1), has been isolated along with a halogenated C15 acetogenin, (3Z)-laurenyne (2), from a new Laurencia species, L.yonaguniensis Masuda et Abe, species inedita, collected at Yonaguni Island, Okinawa Prefecture, Japan. The structures of these metabolites were elucidated by spectroscopic data (IR, 1H NMR, 13C NMR, 2D NMR, and MS). Neoirietetraol (1) was toxic to the brine shrimp (Altemia salina; LC50, 40.1 microM) and also showed weak antibacterial activities against two marine bacteria, Alcaligenes aquamarinus and Escherichia coli.

Halogenated Organic Molecules of Rhodomelaceae Origin: Chemistry and Biology

“…162 Following extensive analyses of NOESY correlations, the stereochemistry of 219 was revised in a recent report, which also described the structures of four similar compounds 220− 223 from L. obtusa collected at Milos Island in the Aegean Sea, Greece. 163 L. obtusa (Serifos Island in the central Aegean Sea, Greece) was the source of the sesquiterpene 8-bromo-9,11-cyclo-4-perforen-3-one (224), 140 while L. tenera (Townsville region of the Great Barrier Reef, Australia) produced 2-epiperforatone (225) 164 and tenerol acetate (226). 165 The structure of 2-epi-perforatone (225) was determined by single-crystal X-ray diffraction.…”

“…67,149,221,225,228 Irieane diterpenes were solely isolated from L. irieii (276−284), 189,190 L. pinnata (285− 287), 191 L. decumbens (288), 192,193 and more recently, from an unrecorded Laurencia species (289), 194 192 and L. similis (576, 577, and 584−586, 588), 185,355,357 352,353,356,358,410 Bromophenols with a 3-bromo-4,5-dihydroxybenzyl unit (598, 360 Despite of some of the characteristic metabolites were found in certain species of the Rhodomelaceae family, it is interesting to note that recollection of the same algal species at the same site and the same season over the consecutive years does not guarantee that only the same metabolites will be obtained. 98 It thus should be noted that, although the presence of these halogenated molecules can be informative, it is not advisable to rely solely on them to make taxonomic assignments, but instead to combine consideration of chemical composition with examination of morphological and cytological features.…”

“…96 The brominated diterpene neoirietetraol (336) exhibited inhibitory activity against two of six species of bacterial isolates tested, Alcaligenes aquamarinus and E. coli, at 100 μg/disc. 225 The halochamigranes elatol (55), iso-obtusol (64), 10,15-dibromo-1,3(15),7(14)-chamigratrien-9-ol (107), and (3E)-bromomethylidene-10β-bromo-β-chamigrene-9β-ol (114) displayed antibacterial activity against"ice-ice" disease pathogens Alteromonas sp1., Alteromonas sp2., Proteus mirabilis, Proteus sp., Cytophaga−Flavobacterium, and Vibrio sp.. 506 The above results suggest that halogenated molecules may play ecological roles in defending the algae against the intrusion of pathogenic marine bacteria.…”

Extracts and Sesquiterpene Derivatives from the Red Alga Laurencia chondrioides with Antibacterial Activity against Fish and Human Pathogenic Bacteria

“…Diterpenes have been discovered in Laurencia obtusa (prevezol A and B) and Laurencia yonaguinensis (neoirietetraol) [6] [7]. Laurencia rigida contains brominated sesquiterpenes; in Laurencia perforata also sesquiterpenes were detected [8] [9].…”

Atividade biológica de metabólitos secundários de algas marinhas do gênero Laurencia

“…Este metabólito foi testado por ensaios de difusão em disco para verificar atividade antibacteriana contra seis espécies de bactérias marinhas. O neoirietetraol mostrou-se ativo contra Alcaligenes aquamarinus e Escherichia coli em uma concentração de 100 µg/disco (Takahashi et al, 2002).…”