Antibacterial scalarane from Doriprismatica stellata nudibranchs (Gastropoda, Nudibranchia), egg ribbons, and their dietary sponge Spongia cf. agaricina (Demospongiae, Dictyoceratida)

• Cora Hertzer,
• Stefan Kehraus,
• Nils Böhringer,
• Fontje Kaligis,
• Robert Bara,
• Dirk Erpenbeck,
• Gert Wörheide,
• Till F. Schäberle,
• Heike Wägele and
• Gabriele M. König

Beilstein J. Org. Chem. 2020, 16, 1596–1605, doi:10.3762/bjoc.16.132

• , Demospongiae). We describe the structure elucidation of the new scalarane sesterterpene 12-deacetoxy-4-demethyl-11,24-diacetoxy-3,4-methylenedeoxoscalarin (Figure 2), isolated from all our Doriprismatica stellata nudibranch, egg ribbon and Spongia cf. agaricina samples (Figure 3). It is the first scalarane

• mentioned in previous studies on nudibranch egg ribbons [17][34][35][36]. The antibacterial activity of 12-deacetoxy-4-demethyl-11,24-diacetoxy-3,4-methylenedeoxoscalarin could point towards a potential protective role against bacterial biofilm formation. Unfortunately, the metabolite was unstable over time

• (Ac) and consecutively methanol (MeOH). The ethanolic storage solutions of D. stellata nudibranch, egg ribbon, and Spongia cf. agaricina samples were each combined with the respective Ac/MeOH extracts of the samples and dried under vacuum to give the crude extracts. After liquid–liquid separation of

Synthesis and determination of the absolute configuration of (−)-(5R,6Z)-dendrolasin-5-acetate from the nudibranch Hypselodoris jacksoni

• I. Wayan Mudianta,
• Victoria L. Challinor,
• Anne E. Winters,
• Karen L. Cheney,
• James J. De Voss and
• Mary J. Garson

Beilstein J. Org. Chem. 2013, 9, 2925–2933, doi:10.3762/bjoc.9.329

• , Australia 10.3762/bjoc.9.329 Abstract A small sample of (−)-(5R,6Z)-dendrolasin-5-acetate, which was fully characterized by 2D NMR studies, was isolated from the nudibranch Hypselodoris jacksoni, along with the sesquiterpenes (+)-agassizin, (−)-furodysinin, (−)-euryfuran, (−)-dehydroherbadysidolide and

• obtained by preparative enantioselective HPLC. Keywords: enantioselective HPLC; E/Z-isomers; Hypselodoris; natural products; nudibranch; sesquiterpene; Introduction Marine organisms have been proven a prolific source of natural products that potentially can be used as lead compounds or which have