Three New Cytotoxic Polyhydroxysteroidal Glycosides from Starfish Craspidaster hesperus

Bright Spots in The Darkness of Cancer: A Review of Starfishes-Derived Compounds and Their Anti-Tumor Action

The fight against cancer represents a great challenge for researchers and, for this reason, the search for new promising drugs to improve cancer treatments has become inevitable. Oceans, due to their wide diversity of marine species and environmental conditions have proven to be precious sources of potential natural drugs with active properties. As an example, in this context several studies performed on sponges, tunicates, mollusks, and soft corals have brought evidence of the interesting biological activities of the molecules derived from these species. Also, echinoderms constitute an important phylum, whose members produce a huge number of compounds with diverse biological activities. In particular, this review is the first attempt to summarize the knowledge about starfishes and their secondary metabolites that exhibited a significant anticancer effect against different human tumor cell lines. For each species of starfish, the extracted molecules, their effects, and mechanisms of action are described.

Cytotoxic Polyhydroxysteroidal Glycosides from Starfish Culcita novaeguineae

Four new polyhydroxysteroidal glycosides—culcinosides A–D (1, 2, 4, and 7)—along with three known compounds—echinasteroside C (3), linckoside F (5), and linckoside L3 (6)—were isolated from the ethanol extract of starfish Culcita novaeguineae collected from the Xisha Islands of the South China Sea. The structures of new compounds were elucidated through extensive spectroscopic studies and chemical evidence, especially two-dimensional (2D) NMR techniques. The cytotoxicity of the new compounds against human glioblastoma cell lines U87, U251, and SHG44 were evaluated.

Marine natural products

Covering: 2016. Previous review: Nat. Prod. Rep., 2017, 34, 235-294This review covers the literature published in 2016 for marine natural products (MNPs), with 757 citations (643 for the period January to December 2016) referring to compounds isolated from marine microorganisms and phytoplankton, green, brown and red algae, sponges, cnidarians, bryozoans, molluscs, tunicates, echinoderms, mangroves and other intertidal plants and microorganisms. The emphasis is on new compounds (1277 in 432 papers for 2016), together with the relevant biological activities, source organisms and country of origin. Reviews, biosynthetic studies, first syntheses, and syntheses that led to the revision of structures or stereochemistries, have been included.

Three New Cytotoxic Steroidal Glycosides Isolated from Conus pulicarius Collected in Kosrae, Micronesia

Three new sulfated steroidal glycosides (3–5), along with known cholesterol derivatives (1,2), were isolated from the visceral extract of the cone snail Conus pulicarius. The structure of each new compound was elucidated by nuclear magnetic resonance spectroscopy and high-resolution mass spectrometry. The three new compounds exhibited significant in vitro cytotoxicity (GI₅₀ values down to 0.49 μM) against the K562 human leukemia cell line.

A New Steroidal Glycoside Granulatoside C from the Starfish Choriaster granulatus, Unexpectedly Combining Structural Features of Polar Steroids from Several Different Marine Invertebrate Phyla

A new unique steroidal glycoside, granulatoside C (1), was isolated from the ethanol extract of the starfish Choriaster granulatus. The structure of 1 was elucidated by extensive NMR and ESI-MS techniques as (20 R)-16,21- O-di-(P-D-fucopyranosyl)-24-methyl-cholesta-5,24(28)-diene-3p,7a,16a,21-tetraol (1). This glycoside is unusual one, because combines some characteristic structural peculiarities of steroids from several different phyla of marine invertebrates, it has a range of structural features that not previously found in starfish polyhydroxysteroidal glycosides, such as Δ5-3β,7α,16α-trihydroxysteroidal nucleus, Δ24(28)-21-hydroxy-24-methyl-cholestane side chain and 16,21-diglycosylation by D-fucopyranosyl residues, but also characteristic of sponges, ophiuroids and soft corals, respectively.