Brominated Selinane Sesquiterpenes from the Marine Brown Alga Dictyopteris divaricata

Abstract

Two new brominated selinane sesquiterpenes, 1-bromoselin-4(14),11-diene (1) and 9-bromoselin-4(14),11-diene (2), one known cadinane sesquiterpene, cadalene (3), and four known selinane sesquiterpenes, α-selinene (4), β-selinene (5), β-dictyopterol (6), and cyperusol C (7), were isolated from a sample of marine brown alga Dictyopteris divaricata collected off the coast of Yantai (China). Their structures were established by detailed MS and NMR spectroscopic analysis, as well as comparison with literature data.

Marine natural products

“…This was the first isolation of these compounds from a marine source. 349 This same alga was also the source of the cadinane sesquiterpenes 306 and 307, and six other known cadinanes. Sargafuran, a novel compound suggested to be of geranylgeraniol/shikimate origin, had low cytotoxicity and could be the basis of a new skin care treatment to prevent or improve acne.…”

Sesquiterpenes from the marine red alga Laurencia composita

“…An inspection of the structure-activity relationship demonstrated that exocylic double bond in 2 and epoxy group in 10-bromo-7α,8α-expoxychamigr-1-en-3-ol, respectively, might be not the key active moieties [3]. The bromine substitution at C-1 in 7 could contribute more to the brine shrimp toxicity than that at C-9 in 8 and the hydroxyl group in β-dictyopterol (lethal rate 22.3% at 100 μg/mL) [8]. Additionally, compound 2 also displayed antifungal activity against C. lagenarium with an inhibitory diameter of 10 mm and no compounds exhibited activity against F. oxysporum by the agar diffusion test at 30 μg/disk.…”

“…Compounds 5-8 were identified to be 2,10-dibromo-3-chloro-7-chamigren-9-ol acetate (5) [6], deoxyprepacifenol (6) [7], 1-bromoselin-4(14),11-diene (7) [8], and 9-bromoselin-4(14),11-diene (8) [8], respectively, based on the NMR data comparison with literature values. 5 was a new naturally occurring sesquiterpene, and its 13 C NMR data were described in Table 2.…”

“…Among our investigated species, Laurencia composita from Nanji Island has been found to be a prolific producer of halogenated chamigrane sesquiterpenes [4,5], which encouraged us to further examine the molecular diversity of this species from other places. The effort on the sample from Pingtan Island resulted in the isolation and identification of four new chamigrane derivatives, laurecomin A (1), laurecomin B (2), laurecomin C (3), and laurecomin D (4), one new naturally occurring sesquiterpene, 2,10-dibromo-3-chloro-7-chamigren-9-ol acetate (5) [6], and three known halogenated structures, deoxyprepacifenol (6) [7], 1-bromoselin-4(14),11-diene (7) [8], and 9-bromoselin-4(14), 11-diene (8) [8]. In this report, we focus on the preparation, structure elucidation, and bioactivity of compounds 1-8 in detail (Fig.…”

Seaweeds as Source of New Bioactive Prototypes

“…Eudesmane sesquiterpenes also been isolated from brown seaweeds, for example, from Dictyopteris divaricata [87]. In red seaweeds, the metabolites 1-bromoselindiene and 9-bromoselindiene (33 and 34) were isolated species Laurencia composita and demonstrate potent toxicity to brine shrimp [88].…”