Steroids from the Brazilian Zoanthids Palythoa caribaeorum and Palythoa variabilis

Abstract

Two unreported ergostane-type sterols 24(R)-7α-hydroperoxy-ergost-5-en-3β-ol and 6β-carboxyl-24(R)-(8→6)-abeo-ergostan-3β,5β-diol, along with seven known ones were isolated from the hexane and alcohol extracts from the zoanthids Palythoa caribaeorum and Palythoa variabilis. The structures of the new compounds were determined using spectroscopic techniques, including 1D and 2D nuclear magnetic resonance (NMR), high-resolution electrospray ionization mass spectrometry (HRESIMS), and comparison with data previously published. 6β-Carboxyl-24(R)-(8→6)-abeo-ergostan-3β,5β-diol showed moderate cytotoxicity against colon cancer cells (HCT-116) as previously described for others abeo-sterol derivatives. Keywords: Palythoa caribaeorum, Palythoa variabilis, ergostane sterols, cytotoxic activity IntroductionZoanthids are cnidarians found in most marine environments, from temperate to tropical areas and from the intertidal zone to the deep sea below 5000 m, but are particularly common in tropical and subtropical seas. The colonial zoanthid genus Palythoa (order Zoantharia) is represented by ca. 92 species.2 It has been the subject of constant taxonomy investigations due to an incomplete understanding of their diversity. lipidic α-amino acids, 13 and pyrazines. 14 Lipids and steroids represent the commonest classes of compounds isolated from Palythoa spp. (Figure 1). The most potent toxic nonprotein known, palytoxin, has been isolated from Palythoa species. 15 The first natural lipid α-amino acids (C 30 and C 31 ) have been isolated from Protopalythoa variabilis, and exhibited cytotoxic effects against human cancer cell lines.13 Protopalythoa taxonomy previously assigned 4,13 is under revision based on mitochondrial DNA analysis, indicating that Protopalythoa and Palythoa are indeed congeneric designations. 16The present investigation reports on the steroidal composition of P. caribaeorum and P. variabilis. Both species are abundant in shallow waters along the Brazilian Northeast coastline. ExperimentalGeneral Infrared (IR) spectra were obtained on a PerkinElmer FT-IR spectrum 1000 spectrometer. Optical rotations were measured on a PerkinElmer 341 digital polarimeter at 25 °C.Steroids from the Brazilian Zoanthids Palythoa caribaeorum and Palythoa variabilis J. Braz. Chem. Soc. 486 Melting points, not corrected, were determined on a digital MQAPF-302 melting point apparatus (Microquimica), with a heating rate of 2 °C min -1 . 1 H (500 or 300 MHz) and 13 C (125 or 75 MHz) nuclear magnetic resonance (NMR) spectra were performed either on a Bruker Avance DRX-500 or Avance DPX-300 spectrometer. High resolution electrospray ionization mass spectrometry (HRESIMS) was acquired using a liquid chromatography-mass spectrometry ion trap and time-of-flight (LCMS-IT-TOF, Shimadzu) spectrometer, consisting of an UFLC (ultra fast liquid chromatography) system coupled to an IT-TOF mass spectrometer equipped with electrospray ionization (ESI) source operating either in positive or negative mode. The mass spectra were recorded in the range ...

Marine natural products

“…562 and ameristerenols A and B and ameristerol A 1342-1344 (Pseudopterogorgia americana), 563 seco-sterol 1345 and ergostane 1346 (Pinnigorgia sp. ), 564 ergostane 1347 (Palythoa caribaeorum) and rearranged ergostane 1348 (P. variabilis), 565 and klyaccisteroids K-M 1349-1351 (Klyxum accidum). 566 The structure of scleronine 1334, which inhibited tumour cell migration, was conrmed and its absolute conguration determined by X-ray diffraction.…”

New Verticillene Diterpenoids, Eudesmane Sesquiterpenoids, and Hydroperoxysteroids from the Further Chemical Investigation of a Taiwanese Soft Coral Cespitularia sp.

“…The extract of Cespitularia sp. was separated by column chromatography and HPLC to afford five new secondary metabolites ( 1 – 5 ) and twelve related known compounds, which were identified as 7α-hydroperoxycampesterol ( 6 ) [ 18 ], 7β-hydroperoxycholesterol ( 7 ) [ 19 ], 7α-hydroperoxycholesterol ( 8 ) [ 19 ], cespitulactam D ( 9 ) [ 11 ], cespitulactam F ( 10 ) [ 11 ], cespitulin S ( 11 ) [ 16 ], cespitularin D ( 12 ) [ 1 ], cespitularin O ( 13 ) [ 8 ], cespitulactone B ( 14 ) [ 10 ], cespihypotin Q ( 15 ) [ 13 ], atractylenolide II ( 16 ) [ 20 ], and atractylenolide III ( 17 ) [ 20 ] ( Figure 1 ). ( Supplementary materials, Figures S1–S68 .)…”

Network pharmacology‐based study to identify the significant pathways of Lentinula edodes against cancer

“…In detail, the dihydroxy ergostane derivative isolated from the Red Sea black coral ( Antipathies dichotoma ) shown potent anticancer effects on HepG2 (human liver cancer cell line) and MCF‐7 (human breast cancer cell line) (Xiao et al, 2020). Another ergostane steroid identified in Brazilian Zoanthids Palythoa variabilis has been demonstrated that inhibited proliferation of HCT‐116 (human colon cancer cell line) (Pinto et al, 2017). An ergostane steroid derivative isolated from Ganoderma capense was effective agent against NCI‐H1650 (human lung cancer cell line) (Tan et al, 2017).…”