Polyhydroxylated Steroids Research Articles

Cytotoxic evaluation of new polyhydroxylated steroids from the Red Sea soft coral Litophyton mollis (Macfadyen, 1936)

An efficient column chromatography of the CH2Cl2/MeOH crude extract from the soft coral Litophyton mollis (Macfadyen, 1936) yielded seven steroids, including five 4α-methylated steroids (1–5) and two 19-oxygenated steroids (6–7). Notably, both compounds 3 and 7 are new, identified as (22E)-4α,24-dimethyl-5α-cholesta-22,24(28)-dien-3β,8β-diol (3) and (22E,24R)-7β-acetoxy-24-methyl-cholesta-5,22-dien-3β,19-diol (7). The chemical structures and relative configurations were elucidated through comprehensive spectroscopic analyses, including 1D and 2D NMR, as well as HRESIMS analysis. The cytotoxicity of metabolites 1–7 was evaluated against three cancer cell lines: MCF-7, HepG2, and NCI-1299. Remarkably, metabolites 6 and 7 exhibited strong cytotoxic activity against MCF-7, with IC50 values of 8.6 and 8.4 μM, respectively, while also showing moderate effects against NCI-1299, with IC50 values of 15.7 and 15.1 μM, respectively. Additionally, steroids 4 and 5 displayed weak cytotoxicity against all three cell lines, with IC50 values in the ranges of 34.7–37.5 and 30.8–46.3 μM, respectively.

Total Syntheses of Polyhydroxylated Steroids by an Unsaturation-Functionalization Strategy.

Highly oxygenated cardiotonic steroids such as ouabain possess a wide spectrum of biological functions and remain significant synthetic challenges. Herein we have applied an unsaturation-functionalization strategy and developed a synthetic method in addressing the C19-hydroxylation issue for efficient synthesis of polyhydroxylated steroids. An effective asymmetric dearomative cyclization allowed the construction of the C19-hydroxy unsaturated steroidal skeleton in only 4 steps from the Hajos-Parrish ketone ketal 7. A synthetic sequence featured C3-OH directed hydrogenation/epoxidation, m-CPBA triggered epoxidation/S N 2' nucleophilic substitution, Birch reduction of enone, and regioselective LiAlH4 reduction furnished the polyhydroxy functionalities on the steroid skeleton in high stereochemical control and efficiency, which has ultimately enabled thetotal synthesis of 19-hydroxysarmentogenin and ouabagenin in 18 and 19 overall steps, respectively. The syntheses of these polyhydroxylated steroids has offered synthetic versatility and practicality in search for new therapeutic agents.

Total Syntheses of Polyhydroxylated Steroids by an Unsaturation‐Functionalization Strategy

AbstractHighly oxygenated cardiotonic steroids, such as ouabain, possess a wide spectrum of biological functions and remain significant synthetic challenges. Herein, we have applied an unsaturation‐functionalization strategy and developed a synthetic method in addressing the C19‐hydroxylation issue for efficient synthesis of polyhydroxylated steroids. An effective asymmetric dearomative cyclization allowed the construction of the C19‐hydroxy unsaturated steroidal skeleton in only four steps from the Hajos‐Parrish ketone ketal 7. The synthetic sequence featured C3−OH‐directed hydrogenation/epoxidation, m‐CPBA‐triggered epoxidation/SN2′ nucleophilic substitution, Birch reduction of an enone, and regioselective LiAlH4 reduction to furnish the polyhydroxy functionalities on the steroid skeleton with high stereochemical control and efficiency. This approach ultimately enabled the total synthesis of 19‐hydroxysarmentogenin and ouabagenin in 18 and 19 steps, respectively, overall. The synthesis of these polyhydroxylated steroids offers synthetic versatility and practicality in the search for new therapeutic agents.

Four bioactive new steroids from the soft coral Lobophytum pauciflorum collected in South China Sea.

Four new polyhydroxylated steroids lobophysterols E–H (1–4), together with three known compounds (5–7), were isolated from the soft coral Lobophytum pauciflorum collected at Xisha Island, China. The structures of the new compounds were elucidated by extensive spectroscopic analysis and comparison with NMR data of structurally related compounds reported in the literature. The absolute configuration of 1–3 was determined by X-ray diffraction. All the compounds have assessed the cytotoxicity against HL-60, K562, and Hela cells. Compound 1 showed weak cytotoxicity against K562 cells with an IC50 value of 19.03 μM. In addition, compound 1 also showed a moderate anti-inflammatory effect in zebrafish.

Ecdysteroids

Ecdysteroid: member of a class of polyhydroxylated steroids found in invertebrate animals (zooecdysteroids; moulting hormones), plants (phytoecdysteroids) and fungi (mycoecdysteroids). Over 500 structural analogues are currently known. Biosynthetically, they derive from C27-, C28- or C29-sterols. The most frequently encountered analogue (in arthropods and plants) is 20-hydroxyecdysone (2β,3β,14α,20R,22R,25-hexahydroxycholest-7-en-6-one). In arthropods, ecdysteroids occur universally and regulate development by inducing moulting and reproduction, where their action is mediated by high-affinity binding to an intracellular member of the class of nuclear receptor (NR) proteins (ecdysteroid receptor; EcR) dimerised with a second NR (USP/RxR). This receptor complex binds to specific DNA promoter sites and regulates gene expression. In plants, ecdysteroids are a class of secondary compounds, occurring in varying amounts in certain species, but not all in others. Phytoecdysteroids are believed to contribute to the reduction of invertebrate predation by acting as feeding deterrents or endocrine disruptors. Ecdysteroids also possess a wide range of positive pharmacological effects in mammals, where the mode of action involves moderate-affinity binding to plasma-membrane-bound receptors and not interaction with the classical NRs for vertebrate steroid hormones.

Isolation of Sesquiterpenoids and Steroids from the Soft Coral Sinularia brassica and Determination of Their Absolute Configuration.

Two undescribed rearranged cadinane-type sesquiterpenoids (1–2), named sinulaketol A-B, together with one new chlorinated steroid (3), one new gorgosterol (4), one known sesquiterpene (5), one known dibromoditerpene (6) and two known polyhydroxylated steroids (7–8) were isolated from the soft coral Sinularia brassica. The structures of these compounds were established by extensive spectroscopic analysis, including HRESIMS, 1D, and 2D NMR spectroscopy. Their absolute configurations were also determined by the ECD calculations and DP4+ probability analysis. Antileishmanial activity of compounds 1–8 was evaluated in vitro against the amastigote forms of Leishmania donovani, in which compounds 3, 6, and 7 inhibited the growth of L. donovani by 58.7, 74.3, 54.7%, respectively, at a concentration of 50 μM. Antimicrobial effect of the isolated compounds were also evaluated against Candida albicans, Staphylococcus aureus, and Escherichia coli. Compound 6, a brominated diterpene, exhibited antimicrobial effect against S. aureus.

Four new polyhydroxylated steroids from the South Sea sponge Plakortis sp.

Four new polyhydroxylated steroids plaksterols A-D (1-4), together with two known related steroids ergost-7,9(11),22-trien-3β,5α,6α-triol (5) and ergosta-6β-methoxy-7,22-diene-3β,5α-diol (6), were isolated from methanol extract of the South China Sea marine sponge Plakortis sp. Their structures were identified by spectroscopic analysis, including NMR, MS, and IR. The cytotoxicity of the polyhydroxylated steroids were evaluated, and compound 6 showed moderate inhibitory activities against K562, HL-60 and BEL-7402 cells.

Unusual Polyhydroxylated Steroids from the Starfish Anthenoides laevigatus, Collected off the Coastal Waters of Vietnam.

Four new polyhydroxylated steroids 1–4 were isolated along with two previously known related steroids 5 and 6 from the methanolic extract of the starfish Anthenoides laevigatus collected off the coastal waters of Vietnam. Structures of new compounds were substantially elucidated by one-dimensional (1D) and two-dimensional (2D) NMR spectroscopy and HRESIMS techniques. Heptaol 1 and hexaol 2 contain the common 5α-cholestane skeleton, while hexaol 3 and heptaol 4 have the rare among starfish steroid compounds 5β-cholestane skeleton. Compounds 1, 5, and 6 do not show cytotoxic effects against normal JB6 Cl41 and cancer HT-29 and MDA-MB-231 cells, however they inhibit cell proliferation and colony formation of cancer HT-29 and MDA-MB-231 cells.

Six new polyhydroxylated steroids conjugated with taurine, microdiscusols A-F, from the Arctic starfish Asterias microdiscus

Six new polyhydroxylated steroids conjugated with taurine, microdiscusols A-F, were isolated from the alcoholic extract of the Arctic starfish Asterias microdiscus. Three of them have been found to have additional sulfate groups in tetracyclic cores. The structures of new compounds were established by 1D and 2D NMR and HRESIMS techniques. The found steroid taurine conjugates resemble, by their structures, salts of bile acids and alcohols of lower vertebrates.

Two new polyhydroxylated steroids from Egyptian soft coral Heteroxenia fuscescens (Fam.; Xeniidae)

Two new polyhydroxylated steroids, 3β-acetoxy-gorgost-5α,6β,11α-triol (3) and (23 R) methylergosta-20-ene-3β,5α,6β,17α-tetrol (4), together with three known gorgosteroid compounds, gorgost-3β, 5α,6β,11α- tetrol (1), 11α-acetoxy-gorgost- 3β,5α, 6β- triol (2), and gorgost-5 (E) ene-3-β-ol (5), as well as batyl alcohol (6), were isolated from the Egyptian soft coral Heteroxenia fuscescens. The structures of these compounds were elucidated based on NMR spectroscopic analyses, HR-FAB-MS, and comparisons with published data. The cytotoxic activities of the fractions and compounds were evaluated against MCF-7 cancer cell lines using MTT colorimetric assay. Compounds 2 and 4 showed moderate cytotoxic activity, with IC50 values equal to 33.2 and 25.1 µM, respectively, in comparison with the IC50 of 5-fluorouracil 18.7 µM.

Cytotoxic polyhydroxylated steroids from the South China Sea soft coral Lobophytum sp.

Four new polyhydroxylated steroids lobophysterols A–D (1–4), together with two known related compounds sarcophytosterol (5) and klyflaccisteroid B (6), were isolated from the South China Sea soft coral Lobophytum sp. Their structures were elucidated on the basis of spectroscopic analysis and by comparison with those reported in the literature. In bioassay, compound 4 showed weak cytotoxicities against HT-29, SNU-398, and Capan-1 cells.

Polyhydroxylated sulfated steroids derived from 5α-cholestanes as antiviral agents against herpes simplex virus.

Twelve polyhydroxylated sulfated steroids synthesized from a 5α-cholestane skeleton with different substitutions in C-2, C-3 and C-6 were evaluated for cytotoxicity and antiviral activity against herpes simplex virus (HSV) by a virus plaque reduction assay. Four compounds elicited a selective inhibitory effect against HSV. The disodium salt of 2β,3α-dihydroxy-6E-hydroximine-5α-cholestane-2,3-disulfate, named compound 7, was the most effective inhibitor of HSV-1, HSV-2 and pseudorabies virus (PrV) strains, including acyclovir-resistant variants, in human and monkey cell lines. Preliminary mechanistic studies demonstrated that compound 7 did not affect the initial steps of virus entry but inhibited a subsequent event in the infection process of HSV.

ChemInform Abstract: Cyclopentenone Derivatives and Polyhydroxylated Steroids from the Soft Coral Sinularia acuta.

AbstractFour new polyhydroxylated steroids and the racemic form of cyclopentanone, sinularone J (IV), are isolated along with four known steroids, one known cyclopentanone derivative, and one known butenolide derivative from the soft coral Sinularia acuta.

A facile method for steroid labeling by heavy isotopes of hydrogen

A new catalytic enantiospecific approach to the synthesis of epibrassinosteroids (and other polyhydroxylated steroids) regiospecifically labeled by heavy isotopes of hydrogen is reported. Chlorocarbonate, efficiently synthesized from α-hydroxy ketone by a reaction with triphosgene, undergoes reductive tritium dechlorination catalyzed by the [Pd0]/Et3N system, providing 24-[3β-3H]epicastasterone and 24-[3β-3H]epibrassinolide, respectively, in good yield and with high specific activity (5.8 Ci/mmol; 20% tritium enrichment per molecule).

Cyclopentenone derivatives and polyhydroxylated steroids from the soft coral Sinularia acuta.

Four new polyhydroxylated steroids, 1-4, and the racemic form of cyclopentenone 9, together with four known steroids, 5-8, one known cyclopentenone derivative, 10, and one known butenolide derivative, 11, were isolated from the soft coral Sinularia acuta collected from Weizhou Island of Guangxi Province, P. R. China. Their structures were elucidated on the basis of spectroscopic analyses and by comparison of the corresponding data with those previously reported. The cytotoxicities of the isolates 1-11 in vitro against the selected tumor cell lines HL-60, HeLa, and K562 were evaluated. Compounds 2 and 5 showed potent cytotoxicities against HL-60 cell lines with IC50 values of 7.3 and 9.9 μM, respectively. Compounds 5 and 6 showed moderate activities against K562 cell lines with IC50 values of 10.9 and 11.7 μM, respectively, while compounds 1, 2, and 6 showed weak activities against HeLa cell lines with respective IC50 values of 44.8, 27.1, and 18.2 μM. This is the first report on chemical and bioactivity research of S. acuta.

ChemInform Abstract: NF‐ϰB Inhibitory Activity of Polyoxygenated Steroids from the Vietnamese Soft Coral Sarcophyton pauciplicatum.

AbstractThe new steroid sarcopanol A (I) is isolated along with two known polyhydroxylated steroids from the soft coral Sacrophyton pauciplicatum.

9,11-Secosteroids and polyhydroxylated steroids from two South China Sea soft corals Sarcophyton trocheliophorum and Sinularia flexibilis

A new 9,11-secosteroid, 25(26)-dehydrosarcomilasterol (1), two new polyhydroxylated steroids, 7α-hydroxy-crassarosterol A (2) and 11-acetoxy-7α-hydroxy-crassarosterol A (3), together with three known related ones (4–6), were isolated from the South China Sea soft corals Sarcophyton trocheliophorum and Sinularia flexibilis, respectively. The structures of the new steroids were elucidated on the basis of extensive spectroscopic analyses, comparison with the literature data and chemical correlation. Compound 2 exhibited a moderate protein tyrosine phosphatase 1B (PTP1B) inhibitory activity with an IC50 value of 33.05μM. Compounds 1–3 showed weak in vitro cytotoxicities against the tumor cell lines K562 and HL-60.

Metabolite profiling of polar steroid constituents in the Far Eastern starfish Aphelasterias japonica using LC–ESI MS/MS

Numerous polar steroids are characteristic metabolites of starfish which determine physiological activities of their extracts. The Far Eastern starfish Aphelasterias japonica is a rich source of different steroid glycosides and polyhydroxysteroids. For detailed analysis of complicated mixture of steroids from this species, isolated by solid-phase extraction, a liquid chromatography–electrospray tandem mass spectrometry (LC–ESI MS/MS) approach was selected and applied. The characteristic fragmentations in ESI MS/MS spectra of steroid glycosides allowed determining types of aglycones, presence of sulfate groups, sugar sequences as well as branching. In addition, main structural features of polyhydroxylated polar steroids including position of hydroxylation and level of sulfation were also established. Totally, 68 metabolites, comprising of 33 asterosaponins, 28 sulfated polyhydroxysteroid mono- and biosides and 7 sulfated polyhydroxysteroid compounds were found by this method. In addition to 15 previously isolated compounds from A. japonica, many new steroid glycosides including asterosaponins with unusual carbohydrate chains were discovered and characterized by their ESI product ion mass spectra. Some details of biosynthesis of polyhydroxylated steroids and their conjugated forms in the species studied such as a role of sulfation and order of introduction of hydroxyl group in A. japonica were proposed.

Novel polyhydroxylated steroids from the East China Sea gorgonian Echinogorgia sassapo reticulata with suppressive activity of leukotriene C4 generation and degranulation in bone marrow-derived mast cells

The gorgonian Echinogorgia sassapo reticulata contains two new bioactive polyhydroxylated steroids, sassapols A (1), B (2), and five related known compounds (3–7). Compound 6 has been encountered for the first time in natural sources. The structures of these new compounds were defined by spectroscopic analysis. All the compounds (1–7) isolated from E. sassapo reticulata were tested for anti-inflammatory activity. Compounds 1, 3, 5, and 7 inhibited both the generation of leukotriene C4 and the degranulation reaction in mouse bone marrow-derived mast cells.

Polyhydroxylated steroids from the South China Sea soft coral Sarcophyton sp. and their cytotoxic and antiviral activities.

Chemical investigation on the soft coral Sarcophyton sp. collected from the South China Sea yielded three new polyhydroxylated steroids, compounds (1–3), together with seven known ones (4–10). Their structures were established by extensive spectroscopic methods and comparison of their data with those of the related known compounds. All the isolates possessed the 3β,5α,6β-trihydroxylated steroidal nucleus. The cytotoxicities against selected HL-60, HeLa and K562 tumor cell lines and anti-H1N1 (Influenza A virus (IAV)) activities for the isolates were evaluated. Compounds 2, 3 and 5–8 exhibited potent activities against K562 cell lines with IC50 values ranging from 6.4 to 10.3 μM. Compounds 1, 6–8 potently inhibited the growth of HL-60 tumor cell lines, and 6 also showed cytotoxicity towards HeLa cell lines. In addition, preliminary structure-activity relationships for the isolates are discussed. The OAc group at C-11 is proposed to be an important pharmacophore for their cytotoxicities in the 3β,5α,6β-triol steroids. Compounds 4 and 9 exhibited significant anti-H1N1 IAV activity with IC50 values of 19.6 and 36.7 μg/mL, respectively.