Three New Polyoxygenated Steroids from Two Species of the South China Sea Gorgonian Muricella flexuosa and Menella verrucosaBrundin

Abstract

Three new polyoxygenated steroids, muricesteroid (1), and menellsteroids A (2) and B (3), were isolated from two species of the South China Sea gorgonian Muricella flexuosa and Menella verrucosa BRUNDIN, respectively. The structures of these new compounds were elucidated on the basis of extensive spectroscopic analysis, chemical methods and comparison with known related compounds. Introduction. -Gorgonians of the genera Muricella and Menella (both of them belong to the family Paramuriceidae, order Gorgonacea, class Anthozoa) is prolific in the South China Sea. A literature survey revealed that the chemical constituents of the gorgonians of the genus Muricella have been intensively investigated. A variety of secondary metabolites with different C-skeletons such as eunicellane diterpenoids [1 -3], 9,11-secosteroids [4] [5], and a carotenoid [6] were reported from various species of this genus, and some of them exhibited potent cytotoxic activities against several tumor cell lines [2] [3] [5], and toxic effects to brine-shrimp as well [2 -6]. In contrast, chemical studies on the genus Menella were relatively rare. In particular, no chemical study has been done on the Hainan gorgonian Menella verrucosa BRUNDIN, except for our recent work [7c] reporting five new uncommon guaiane lactones from the species. Recently, in the course of our systematic studies on the chemical constituents of the South China Sea gorgonians [7], we have made a collection of Muricella flexuosa off Sanya, Hainan Province, China. Chemical investigation of the Et 2 Menella verrucosa, allowed to isolate two new polyhydroxylated steroids, named menellsteroids A (2) and B (3), respectively. Herein, we describe the isolation and structural elucidation of these new metabolites. Results and Discussion. -Both gorgonians were collected off the coast of Xiaodong Hai, Hainan Province, China, in December 2001, at a depth of 20 m. The animals were immediately put at À 208 and kept frozen until extraction. Frozen materials of Muricella

A Novel Cyclopentene Derivative and a Polyhydroxylated Steroid from a South China Sea Gorgonian Menella sp.

“…The 1 Hand 13 C-NMR spectra showed characteristic signals of five methyls, including two tertiary ones (C-18, 19) and three secondary methyls at d H /d C 0.99/19.2 (C-21), 0.89/22.9 (C-26) and 0.89/23.2 (C-27), which in collaboration with its typical C-3 oxygenated proton signal at d H 4.02 (m, H-3) and one at d H 3.46 (br s, H-6) due to both C-5 and C-6 hydroxylated in its 1 H-NMR, suggested 2 a polydroxylated cholestan-type steroid. A detailed comparison of its NMR data with those of menellsteroid A (3) 7,9) showed both are isomers with high structural similarity (Fig. 1), which was supported and confirmed by the HMBC spectra (Fig.…”

“…Its molecular formula was determined as C 11 7. These data implied 1 to be a highly oxygenated compound with a single ring.…”

“…[1][2][3][4] However, one of the prolific gorgonian in the South China Sea, the Menella sp., has been given comparatively less attention, with the exception of four papers that described the guaiane sesquiterpenoids, polyhydroxylated steroids and other known compounds. [5][6][7][8] As a part of our systematic research on the structurally novel and significantly bioactive metabolites from South China Sea invertebrates, we undertook a chemical investigation on an unidentified gorgonian species Menella sp., collected on Hainan Island. This resulted in the isolation and structure elucidation of a novel constituent, we named menellin A (1), and a polyhydroxylated steroid menellsteroid C (2), together with eight known compounds (3)(4)(5)(6)(7)(8)(9)(10), including a new natural product (7).…”

“…[5][6][7][8] As a part of our systematic research on the structurally novel and significantly bioactive metabolites from South China Sea invertebrates, we undertook a chemical investigation on an unidentified gorgonian species Menella sp., collected on Hainan Island. This resulted in the isolation and structure elucidation of a novel constituent, we named menellin A (1), and a polyhydroxylated steroid menellsteroid C (2), together with eight known compounds (3)(4)(5)(6)(7)(8)(9)(10), including a new natural product (7). The structures of these new compounds were elucidated by spectrum analysis of MS, 1D and 2D NMR.…”

(-)-Hydroxylindestrenolide, a New Sesquiterpenoid from a Gorgonian Coral Menella sp. (Plexauridae)

“…Based on these findings, the C-8 hydroxy group in 1 should be a-oriented by comparison the structure of 1 with that of 2. Chemical investigations of the gorgonian corals belonging to the genus Menella have afforded a diverse range of secondary metabolites, [1][2][3][4][5][6][7] however, the sesquiterpenoids possessing the carbon skeleton as presented as 1 are rarely found in marine organisms. 12) In bioactivity testing, sesquiterpenoid 1 was found to exhibit marginal cytotoxicity toward HL-60 human promyelocytic leukemia and K562 human erythromyeloblastoid leukemia tumor cells (IC 50 ϭ15.6, 38.7 mg/ml), respectively, but not active toward DU-145 human prostate tumor cells IC 50 Ͼ40 mg/ml).…”