Five new C26 tetracyclic terpenes from a sponge (Lendenfeldia sp.)

Abstract

Five new scalarane sesterterpenes have been isolated from a Western Australian sponge (Lendenfeldia sp.). As with earlier reported examples of these compounds, several of these metabolites of this sponge are extremely potent inhibitors of platelet aggregation.

Cytotoxic Metabolites from an Indonesian Sponge Lendenfeldia sp.

“…Analysis of the 1 H-1 H COSY and 1 H-13 C HMQC spectra suggested that the structure of 2 contained four spin systems: -CH(1)-CH(2)-, -CH 2 (5)-CH 2 (6)-CH (7) H spin systems were connected through the observation of longrange 1 H-13 C correlations in the HMBC spectrum from C-3 to H-1, H-2, H-4, H-5, H-6; from C-8 to H-6, H-7, H-9, H-10, H-20; and from C-12 to H-10, H-11, H-13, H-14, H-21. Therefore, the structure was deduced to be that of a new furanolipid.The 1 H, 13 C and 13 C DEPT NMR spectra of 3 -5 were closely comparable with those of three previously reported Lendenfeldia homoscalarane sesterterpenes, namely, 16β,22-dihydroxy-24-methyl-24-oxoscalaran-25,12β-olactone (3), 6 24-methyl-12,24,25-trioxoscalar-16-en-22-oic acid (4), 6 and 12,16-dihydroxy-24-methylscalaran-25,24-olide (5), 7 respectively.The effects of 1-5 on HIF-1 activity were examined initially in a cell-based reporter assay. 2 The level of HIF-1 activation was measured using the T47D breast tumor cell line that was transiently transfected with the pHRE-TK-Luc reporter as described previously.…”

“…The active fraction that eluted with 100% EtOAc (45.1 mg) was separated by column chromatography over 450 mg silica gel with hexanes-CH 2 Cl 2 -EtOAc (1:1:2) to give 3 (7.0 mg, 0.17% yield), and 4 (10.0 mg, 0.25% yield). (4aR,4bS,6aS,7S,10aS,10bS,3,4,4b,5,6,6a,7,10,10a,10b,11,12,12a-t etradecahydro-1,1,6a,10b-tetramethyl-6-oxo-4a(2H)-chrysenecarboxylic acid. …”

Concise stereoselective synthesis of marine sesterterpene, 16-deacetoxy-12-epi-scalarafuran acetate and its 14-epimer via intramolecular Diels–Alder addition

“…A range of scalarane sesterterpenoids, 1 which display a variety of biological activities, such as cytotoxicity, 2 antifeedant activity, 3 anti-inflammatory 4 and platelet-aggregation inhibitory effects, 5 have been isolated from different marine organisms during the past three decades. Many members of this group of scalaranic sesterterpenes possess ABCDE pentacyclic fused ring skeletons I ( Fig.…”

Investigations of the Marine Flora and Fauna of the Islands of Palau

“…71), 43 three of which had been described previously from an Australian Lendenfeldia sp. 44 and it was reported that 24-methylscalaradial 71 inhibited platelet aggregation with an IC 50 of 0.5 µg mL Ϫ1 .…”