Leptogorgins A–C, Humulane Sesquiterpenoids from the Vietnamese Gorgonian Leptogorgia sp.

Abstract

Leptogorgins A–C (1–3), new humulane sesquiterpenoids, and leptogorgoid A (4), a new dihydroxyketosteroid, were isolated from the gorgonian Leptogorgia sp. collected from the South China Sea. The structures were established using MS and NMR data. The absolute configuration of 1 was confirmed by a modification of Mosher’s method. Configurations of double bonds followed from NMR data, including NOE correlations. This is the first report of humulane-type sesquiterpenoids from marine invertebrates. Sesquiterpenoids leptogorgins A (1) and B (2) exhibited a moderate cytotoxicity and some selectivity against human drug-resistant prostate cancer cells 22Rv1.

Marine natural products

“…), 535 humulanes leptogorgins A–C 1192–1194 ( Leptogorgia sp. ), 536 caryophyllanes rumphellolides K 1195 and L 1196 , antipacids A 1197 and B 1198 and clovanediol 1199 ( Rumphella antipathes ), 537,538 linardosinenes A–C 1200–1202 , lineolemnenes A–D 1203–1206 and known neolemnane 1207 ( Litophyton nigrum ), 539 hydroperoxide heterofusceterpene A 1208 ( Heteroxenia fuscescens ), 540 and a series of sesquiterpenoids 1209–1211 and 1213 and diterpenoid 1212 ( Sinularia tumulosa ). 541 Of note was the pro-angiogenic activity observed for clavukoellian K 1191 .…”

New Bioactive Sesquiterpeniods From the Plant Endophytic Fungus Pestalotiopsis theae

“…While NOESY correlation ( Figure 3 and Supplementary Figure 12 ) of H-4 with H 3 -16 indicated that H-4 and H 3 -16 were in the β-orientation, thus establishing the relative configuration of 2 . The absolute configuration of C-9 in 2 was deduced as 9 S on the basis of biosynthetic considerations and by analogy to 1 , 4 , and 5 ( Liao et al, 2013 ; Kapustina et al, 2020 ). The absolute configurations of C-4 and C-5 in 2 were also deduced by comparison of the experimental and calculated ECD spectra for the two stereoisomers, (4 R , 5 R , 9 S )- 2 ( 2a ) and (4 S , 5 S , 9 S )- 2 ( 2b ) ( Figure 5 ).…”

“…Sesquiterpenoids are a group of naturally occurring 15-carbon isoprenoids, showing diverse structural features and interesting bioactivities ( Fraga, 2011 , 2013 ). Humulane-type sesquiterpenoids represent an uncommon type of compound possessing a characteristic 11-membered ring in the molecule, which display a wide range of bioactivities including antibacterial, antifungal, cytotoxic, and immunosuppressive activities ( Pulici et al, 1996a ; Toyota et al, 2004 ; Luo et al, 2006 ; Liao et al, 2013 ; Chen et al, 2014 ; Wang et al, 2017 ; Kapustina et al, 2020 ). Caryophyllene-derived sesquiterpenoids are a group of structurally unique compounds characterized by the presence of a bicyclo[2.7.0]undecane skeleton, which are believed to be derived from humulane ( Ayer and Browne, 1981 ; Daniewsk et al, 1981 ).…”

Chemical Diversity of Soft Coral Steroids and Their Pharmacological Activities

“…The soft coral Lobophytum michaelae that lives on the coast of Taitung and its ethyl acetate extract contained three cytotoxic polyoxygenated steroids called michosterols A-C (157-159) [148] and also ethyl acetate extract the gorgonian Leptogorgia sp. collected from the South China Sea contained dihydroxy-ketosteroid (160) [149]. The structures of the steroids are shown in Figure 8 and the potential biological activities are shown in Table 9.…”