Cadinane Sesquiterpenes from the Brown Alga Dictyopteris divaricata

Abstract

Seven new cadinane sesquiterpenes, (-)-(1R,6S,7S,10R)-1-hydroxycadinan-3-en-5-one (1), (+)-(1R,5S,6R,7S, 10R)-cadinan-3-ene-1,5-diol (2), (+)-(1R,5R,6R,7S,10R)-cadinan-3-ene-1,5-diol (3), (+)-(1R,5S,6R,7S,10R)-cadinan-4(11)-ene-1,5-diol (4), (+)-(1R,5R,6R,7R,10R)-cadinan-4(11)-ene-1,5,12-triol (5), (-)-(1R,4R,5S,6R,7S, 10R)-cadinan-1,4,5-triol (6), and (-)-(1R,6R,7S,10R)-11-oxocadinan-4-en-1-ol (7), together with nine known compounds were isolated from the brown alga Dictyopteris divaricata. The structures of the new natural products, as well as their absolute configuration, were established by means of spectroscopic data including IR, HRMS, 1D and 2D NMR, single-crystal X-ray diffraction, and CD. All compounds were inactive against several human cancer cell lines including lung adenocarcinoma (A549), stomach cancer (BGC-823), breast cancer (MCF-7), hepatoma (Bel7402), and colon cancer (HCT-8) cell lines.

A New Epoxy-cadinane Sesquiterpene from the Marine Brown Alga Dictyopteris divaricata

“…The 13 C-NMR spectrum along with the DEPT and HSQC experiments revealed the presence of four methyls, four methylenes, five methines, and two quaternary carbon atoms. A detailed comparison of the above spectral data with those reported for cadinan-1,4,5-triol ( 2 ) revealed that 1 differed from 2 mainly at C-4 and C-5 [5], so 1 could be a dehydrated product of 2 between the hydroxyl groups at C-4 and C-5 according to the upfield-shifted C-4, C-5, and H-5 [10]. The 1 H- 1 H COSY correlations as shown in Table 1 and the observed HMBC (Figure 2) correlations from H-12 to C-7, C-11, and C-13, from H-13 to C-7, C-11, and C-12, from H-14 to C-1, C-9, and C-10, from H-15 to C-3, C-4, and C-5, from H-5 to C-1, C-4, C-6, and C-15, and from HO-1 to C-1, C-6, and C-10 confirmed the gross structure of 1 .…”

“…Continuing chemical investigation of the secondary metabolites of D. divaricata collected off the coast of Yantai has led to the isolation of one new cadinane sesquiterpene, 4 β ,5 β -epoxycadinan-1 β -ol ( 1 ), and six known cadinane sesquiterpenes: cadinan-1,4,5-triol ( 2 ) [5], 4 α ,5 β -dihydroxycubenol ( 3 ) [6], cubenol ( 4 ) [6], cadinan-3-ene-1,5-diol ( 5 ) [5], cubenol-3-one ( 6 ) [6], and torreyol ( 7 ) [6]. The isolation of compounds 1 – 7 and structural determination of compound 1 are presented.…”

What are and where are the bioactive terpenoids metabolites from Dictyotaceae (Phaeophyceae)

“…Halogenated sesquiterpenes (whose main sources are the red algae) are reported in Padina antillarum (Parameswaran et al, 1994(Parameswaran et al, , 1996 and Dictyopteris divaricata , and sesquiterpenes without halogens in Dictyopteris divaricata (Song et al, 2005(Song et al, , 2006Qiao et al, 2009;Wen et al, 2009), D. undulata (Song et al, 2004a) and Taonia atomaria (De Rosa et al, 1994). For the latter two genera, 36 and six species are recognized, respectively, while for Padina 37 species are still valid.…”

Brominated Selinane Sesquiterpenes from the Marine Brown Alga Dictyopteris divaricata

“…The marine brown alga Dictyopteris divaricata , found widely spread along the coasts of China, has provided many structurally interesting sesquiterpenes and norsesquiterpenes [1–4]. However, to date there have been no reports of halogenated structures isolated from this species.…”