Bioactive asterosaponins from the starfish Luidia quinaria and Psilaster cassiope. Isolation and structure characterization by two-dimensional NMR spectroscopy

Identification of azukisapogenol triterpenoid saponins from Oxytropis hirta Bunge and their aphicidal activities against pea aphid Acyrthosiphon pisum Harris

BACKGROUND

Acyrthosiphon pisum Harris is the most destructive pest worldwide because of its ability to feed on plants directly and transmit plant viruses as a vector. This study aims to identify triterpenoid saponins from Oxytropis hirta Bunge as biopesticides to control aphids.

RESULTS

Three new azukisapogenol triterpenoid saponins (1-3), a new pinoresinol lignan glycoside (8), and four known saponins (4-7) were identified from the root of O. hirta. Compounds 4-7 displayed significant aphicidal activities against A. pisum with oral toxicities (LC₅₀  = 51.10-147.43 μg/mL, 72 h), deterrent effects (deterrence index = 1.00, 100-200 μg/mL, 24 h), and aphid reproduction inhibitory effects (inhibition rates = 75.91-86.73%, 400 μg/mL, 24 h), respectively. The carboxyl groups at C-3 GlcA and C-30 were functional groups for their aphicidal activities. The toxic symptoms caused by the optimal 5 involved insect body-color changes from light green to dark or gray-green, and then brown until death. The intestinal cavity, apical microvilli, nuclei, mitochondria, and electron dense granules in the midgut tissues of A. pisum were the target sites showing aphicidal activity. The suppression of pepsin and α-amylase, and the activation of lipase and trypsin could be the signs of organelle damage in the midgut tissues.

CONCLUSION

Azukisapogenol triterpenoid saponins from O. hirta could be used as biopesticides to control aphids for their multiple efficacies, including oral toxicity, deterrent activity, and reproduction inhibitory activity. The toxic symptoms involved insect body-color changes. Midgut tissues and their related enzymes were the targets for saponins showing aphicidal activities. © 2022 Society of Chemical Industry.

New triterpenoid saponins from the whole plants of Clematis heracleifolia

Three new triterpenoid saponins, heracleifolianosides A-C (1-3), together with seven known compounds (4-10), were isolated from the whole plants of Clematis heracleifolia. Moreover, three new secondary saponins (1a, 2a and 3a), two known secondary metabolites (5a and 7a) were obtained by alkaline hydrolysis. Their structures were elucidated by extensive spectroscopic analysis and chemical evidences. The cytotoxicity of eight native saponins and five prosapogenins against human breast tumor MDA-MB-231 and gastric carcinoma SGC-7901 cell lines were evaluated by MTT method. Remarkably, the prosapogenin monodesmosidic saponin 7a showed significant cytotoxicity against MDA-MB-231 or SGC-7901 cell lines with IC₅₀ values in the range of 6.05-6.32 μmol/L. It is suggested that it might be a feasible way to change the inactive bisdesmosic triterpenoid saponins to active monodesmosic saponins by a simple procedure of alkaline hydrolysis.

Asterosaponins: Structures, Taxonomic Distribution, Biogenesis and Biological Activities

Asterosaponins are a class of steroid oligoglycosides isolated from starfish with characteristic structures and diverse biological activities. In this review, we have attempted to combine the most important data concerning asterosaponins and give a list of these secondary metabolites with their structural peculiarities. The purpose of this review is to provide a brief but as complete as possible principal information about their chemical structures, taxonomic distribution in the marine environment, distribution in different geographical areas and depths, some properties, biological activities, and functions. Some other rare steroid metabolites from starfish, closely related in structures and probably biogenesis to asterosaponins, are also discussed.

Triterpene glycosides from Silene odontopetala

Silene species are known for their use in traditional medicine in treating several diseases. To the authors' knowledge there is no report on the chemical composition of S. odontopetala. Therefore, the phytochemical investigation of the methanol extract of S. odontopetala was carried out, leading to the isolation of six undescribed oleanane-type glycosides along with the known saponin azukisaponin IV. Their structures were elucidated by the analysis of 1D and 2D-NMR experiments, along with mass spectrometry analysis. The cytotoxic activity of oleanane-type saponins was evaluated against a small panel of cancer cell lines, including PC-3 (prostate carcinoma cells), MCF-7 (breast cancer cells), A549 (alveolar basal carcinoma cells), and HeLa (cervical carcinoma cells). Furthermore, the activity of isolated compounds against a normal cell line HEK-293, used for assessing their cytotoxicity, was evaluated.

Annual assessment of the sea urchin (Paracentrotus lividus) humoral innate immune status: Tales from the north Portuguese coast

Innate immune status of the sea urchin Paracentrotus lividus population from two different rocky shore beaches in the northern Portuguese coast was evaluated for a period of one year. Although some ecological studies regarding the effect of toxics on the immune parameters of the sea urchin were made in Portuguese waters, there is a current lack of knowledge concerning their immune status all over the year. In perspective of a changing ecosystem in these waters due to global warming and colonization of new species, it is important to assess the status of the major species living in the area. In this way, immune parameters such as total protein content, nitric oxide concentration, haemolytic activity, protease activity, lysozyme concentration and bactericidal activity were evaluated in the perivisceral coelomic fluid, and were correlated with the gonadal index of the population and water parameters. Also, the spawning period can upset some immune status parameters, and others such as haemolytic activity and bactericidal activity against Vibrio anguillarum, showed a clear correlation with the gonad maturation status. The knowledge of the basal immune status of the species could serve as ecological indicator of some stress agent or contaminant into the field; also, coelomic fluid is suggested as good quality marker to assess the immune status of sea urchins.

Ancient acquisition of "alginate utilization loci" by human gut microbiota

In bacteria from the phylum Bacteroidetes, the genes coding for enzymes involved in polysaccharide degradation are often colocalized and coregulated in so-called “polysaccharide utilization loci” (PULs). PULs dedicated to the degradation of marine polysaccharides (e.g. laminaran, ulvan, alginate and porphyran) have been characterized in marine bacteria. Interestingly, the gut microbiome of Japanese individuals acquired, by lateral transfer from marine bacteria, the genes involved in the breakdown of porphyran, the cell wall polysaccharide of the red seaweed used in maki. Sequence similarity analyses predict that the human gut microbiome also encodes enzymes for the degradation of alginate, the main cell wall polysaccharide of brown algae. We undertook the functional characterization of diverse polysaccharide lyases from family PL17, frequently found in marine bacteria as well as those of human gut bacteria. We demonstrate here that this family is polyspecific. Our phylogenetic analysis of family PL17 reveals that all alginate lyases, which have all the same specificity and mode of action, cluster together in a very distinct subfamily. The alginate lyases found in human gut bacteria group together in a single clade which is rooted deeply in the PL17 tree. These enzymes were found in PULs containing PL6 enzymes, which also clustered together in the phylogenetic tree of PL6. Together, biochemical and bioinformatics analyses suggest that acquisition of this system appears ancient and, because only traces of two successful transfers were detected upon inspection of PL6 and PL17 families, the pace of acquisition of marine polysaccharide degradation system is probably very slow.

Chemical Profile of the Sulphated Saponins from the Starfish Luidia senegalensis Collected as by-Catch Fauna in Brazilian Coast

The by-catch fauna of the shrimp fishery includes a number of marine invertebrates that are discarded because they do not have commercial value. In order to try to add some value to these materials, we analyzed the chemical composition of the starfish Luidia senegalensis collected in the Brazilian coast as a consequence of the trawling fishery method. In order to access their chemical composition, we used a combination of solid phase extraction (SPE) followed by ultra-high performance liquid chromatography coupled to electrospray ionization ion trap tandem mass spectrometry (UPLC-ESI-IT-MSⁿ). Luidia senegalensis contains asterosaponins, which are sulphated glycosilated steroids, containing five and six sugar moieties, in addition to polyhydroxysteroids. This study helped us to support the presence of important and potentially bioactive compounds in invertebrates associated to the by-catch fauna of the shrimp fishery, using a fast and efficient method.

Triterpenoid Saponins from Anemone rivularis var. Flore-Minore and Their Anti-Proliferative Activity on HSC-T6 Cells

Five previously undescribed triterpenoid saponins (1–5), along with eight known ones (6–13), were isolated from the whole plants of Anemone rivularis var. flore-minore. Their structures were clarified by extensive spectroscopic data and chemical evidence. For the first time, the lupane-type saponins (3 and 12) were reported from the Anemone genus. The anti-proliferative activity of all isolated saponins was evaluated on hepatic stellate cells (HSC-T6). Saponins 12 and 13, which possess more monosaccharides than the others, displayed potent anti-proliferative activity, with IC₅₀ values of 18.21 and 15.56 μM, respectively.

Polar steroid derivatives from the Vietnamese starfish Astropecten polyacanthus

Five polar steroid derivatives, including one new glycosylated polyhydroxysteroid namely polyacanthoside A (1), were isolated from the water-soluble materials from the MeOH extract of the Vietnamese starfish Astropecten polyacanthus using various chromatographic separations. The structure elucidation was confirmed by spectroscopic experiments such as HR-ESI-MS, 1D and 2D NMR. Among the isolated compounds, (20R,24S)-3β,6α,8,15β,24-pentahydroxy-5α-cholestane (3) showed significant cytotoxic effect against five human cancer cell lines as HepG2, KB, LNCaP, MCF7 and SK-Mel2 with the IC₅₀ values from 18.03 ± 2.63 to 21.59 ± 3.23 μM.

Fimbriatols A-J, Highly Oxidized ent-Kaurane Diterpenoids from Traditional Chinese Plant Flickingeria fimbriata (B1.) Hawkes

Fimbriatols A–J (1–10), ten new ent-kaurane diterpenoids possessing differently highly oxidized sites, were isolated from Flickingeria fimbriata (B1.) Hawkes. The structures of these new compounds were determined by HRESI-MS, NMR, CD spectra and X-ray diffraction analysis. Compound 1 displayed moderately inhibitory ratio (48.5%) compared with the positive compound NSC-87877 (81.6%) at the concentration of 0.022 μg/mL. Compounds 7–10 possess 3, 4-seco-ent-kaurane skeleton containing a disaccharide moiety with an unusual linkage at C-2′ to C-1′′ instead of the common linkage at C-6′ to C-1′′, and this is the first report in 600 more ent-kauranes found in nature, which might be originated from ent-kaurane diterpenoids through post-modified reactions of Baeyer-Villiger oxygenation and glycosylation.

Synthesis of the pentasaccharide moiety of starfish asterosaponin luidiaquinoside and its conformational analysis

Pentasaccharide moiety of starfish asterosaponin luidiaquinoside has been synthesized using sequential glycosylation strategy and its conformational analysis was carried out.

Two new triterpenoid saponins from the aerial parts of Anemone taipaiensis

Phytochemical study on the aerial parts of Anemone taipaiensis for the first time led to the isolation of two new oleanane-type triterpenoid saponins 1 and 2, together with four known saponins (3-6). Their structures were elucidated by extensive spectroscopic analysis and chemical evidences. Saponins 2-4 exhibited cytotoxicity against human glioblastoma U251MG cell line with IC50 values ranging from 1.56 to 80.62 μM.

Four new furostanol saponins from the rhizomes and roots of Smilax scobinicaulis and their cytotoxicity

Four new furostanol saponins 1–4, along with two known furostanol saponins 5 and 6 and one known spirostanol saponin 7 were isolated from the rhizomes and roots of Smilax scobinicaulis. The structures of the new saponins were elucidated as 26-O-β-d-glucopyranoside-3β,26-dihydroxy-(25R)-5α-furostan-22-methoxyl-6-one-3-O-α-l-arabinopyranosyl-(1→6)-β-d-glucopyranoside (1), 26-O-β-d-glucopyranoside-3β,26-dihydroxy-(25R)-5α-furostan-22-methoxyl-6-one (2), 26-O-β-d-glucopyranoside-3β,26-dihydroxy-(25R)-5α-furostan-20(22)-en-6-one (3), 26-O-β-d-glucopyranoside-3β,23,26-trihydroxy-(23R, 25R)-5α-furostan-20(22)-en-6-one (4) on the basis of spectroscopic analysis. The isolated saponins were evaluated for cytotoxic activity against two human cancer cell lines including Hela (cervical carcinoma) and SMMC-7221 (hepatocellular carcinoma). Compounds 1 and 7 demonstrated cytotoxicity against the tested cell lines.

Oleanane-type glycosides from Tremastelma palaestinum (L.) Janchen

Three new oleanane-type glycosides, 1-3, were isolated from the whole plant of Tremastelma palaestinum (L.) Janchen, along with eight known triterpene glycosides. The structures of the new compounds were established as 3-O-[β-d-glucopyranosyl-(1→3)-α-l-rhamnopyranosyl-(1→3)-β-d-glucopyranosyl-(1→3)-α-l-rhamnopyranosyl-(1→2)-α-l-arabinopyranosyl]hederagenin (1), 3-O-[β-d-glucopyranosyl-(1→3)-α-l-rhamnopyranosyl-(1→3)-β-d-glucopyranosyl-(1→3)-α-l-rhamnopyranosyl-(1→2)-α-l-arabinopyranosyl]hederagenin 28-O-β-d-glucopyranosyl-(1→6)-β-d-glucopyranosyl ester (2), and 3-O-[α-l-rhamnopyranosyl-(1→3)-β-d-glucopyranosyl-(1→3)-α-l-rhamnopyranosyl-(1→2)-α-l-arabinopyranosyl]oleanolic acid 28-O-β-d-glucopyranosyl-(1→6)-β-d-glucopyranosyl ester (3) by using 1D- and 2D-NMR techniques and mass spectrometry. This is the first report on the phytochemical investigation of a species belonging to Tremastelma genus.

Unusual fernane and gammacerane glycosides from the aerial parts of Spergula fallax

The aerial parts of Spergula fallax afforded four glycosides (1-4) based on two new triterpene aglycones (1a and 2a), along with the known hopane glycoside succulentoside A. Compound 1 was identified as belonging to the fernane class, unusual migrated hopane triterpenoids, mainly isolated from ferns and only rarely from higher plants. Compounds 2-4 were assigned as gammacerane glycosides, having as aglycone a hydroxylated derivative of tetrahymanol. The structures of the isolated compounds 1-4 and their aglycones 1a and 2a obtained by acid hydrolysis were elucidated by spectroscopic data interpretation. The growth inhibitory activity of the isolated compounds and their aglycones was evaluated against the HeLa and DLD-1 cancer cell lines.

Cytotoxic oleanane-type triterpenoid saponins from the Rhizomes of Anemone rivularis var. flore-minore

Phytochemical investigation of the n-BuOH extract of the rhizomes of Anemone rivularis var. flore-minore led to the isolation of five new oleanane-type triterpenoid saponins 1-5, together with five known saponins 6-10. Their structures were determined by the extensive use of 1D and 2D NMR experiments, along with ESIMS analyses and acid hydrolysis. The aglycone of 4 and 5 was determined as 21α-hydroxyoleanolic acid, which was reported in this genus for the first time. The cytotoxicity of these compounds was evaluated against four human cancer cell line, including HL-60 (promyelocytic leukemia), HepG2 (hepatocellular carcinoma), A549 (lung carcinoma) and HeLa (cervical carcinoma). The monodesmosidic saponins 6-8 exhibited cytotoxic activity toward all tested cancer cell lines, with IC50 values in the 7.25-22.38 μM range.

Unusual secondary metabolites from Astragalus halicacabus LAM

From the whole plant of Astragalus halicacabus (Sect. Halicacabus), a new cycloartane-type glycoside, (20R,24S)-3-O-[α-L-arabinopyranosyl-(1→2)-β-D-xylopyranosyl]-20,24-epoxy-16-O-β-D-glucopyranosyl-3β,6α,16β,25-tetrahydroxycycloartane, and a new glycoside, 3-O-[β-D-apiofuranosyl-(1→2)-β-D-glucopyranosyl]maltol were isolated together with seven known cycloartane-type glycosides, i.e., cyclocanthoside D, askendosides D, F, and G, cyclosieversioside G, cyclostipuloside A, elongatoside, and a known maltol glucoside, 3-O-β-D-glucopyranosylmaltol. The structures were elucidated by means of high-resolution mass spectrometry, and extensive 1D- and 2D-NMR spectroscopic analysis. This is the first phytochemical work on A. halicacabus, and a maltol glycoside was encountered for the first time in the Leguminosae family.

Saponins with highly hydroxylated oleanane-type aglycones from Silphium asteriscus L

Silphium asteriscus L., commonly known as starry rosinweed, is a plant found in prairies, glades, woodlands and savannas of the southeastern United States. The phytochemical investigation of the methanolic extract of S. asteriscus leaves led to the isolation of eighteen saponins with highly hydroxylated oleanane-type aglycones never reported before. Their structures were elucidated by extensive spectroscopic methods including 1D- ((1)H and (13)C) and 2D-NMR (DQF-COSY, HSQC, HMBC, TOCSY and ROESY) experiments as well as ESIMS analysis. The antiproliferative activity of the isolated compounds was evaluated against three cancer cell lines including Hela (human epitheloid cervix carcinoma), Jurkat cells (leukaemic T-cell line) and DLD-1 (colorectal adenocarcinoma). Compounds 1, 5 and 17 displayed weak activity with IC50 values ranging from 50 to 75 μM.

Triterpene saponins from the aerial parts of Trifolium medium L. var. sarosiense

Seven previously unreported triterpene glycosides (1-7) were isolated from methanol extract of the aerial parts of Trifolium medium var. sarosiense (zigzag clover). Their structures were established by the extensive use of 1D and 2D NMR experiments along with ESI-MS and HRMS analyses. Compounds 1-7 are oleanane derivatives characterized by the presence of a keto group at C-22 of an aglycone and a primary alcoholic function at C-24 and differing functions at C-30. Among these, compounds 1-3 and 6 showed a secondary alcoholic function at C-11, which is methoxylated in compounds 4 and 7. Compound 5 was shown to possess a known aglycone, wistariasapogenol A; however, it is described here for the first time as a saponin constituent of the Trifolium genus. Some aspects of taxonomic classification of zigzag clover are also discussed.

Anti-inflammatory asterosaponins from the starfish Astropecten monacanthus

Four new asterosaponins, astrosteriosides A-D (1-3 and 5), and two known compounds, psilasteroside (4) and marthasteroside B (6), were isolated from the MeOH extract of the edible Vietnamese starfish Astropecten monacanthus. Their structures were elucidated by chemical and spectroscopic methods including FTICRMS and 1D and 2D NMR experiments. The effects of the extracts and isolated compounds on pro-inflammatory cytokines were evaluated by measuring the production of IL-12 p40, IL-6, and TNF-α in LPS-stimulated bone marrow-derived dendritic cells. Compounds 1, 5, and 6 exhibited potent anti-inflammatory activity comparable to that of the positive control. Further studies are required to confirm efficacy in vivo and the mechanism of effects. Such potent anti-inflammatory activities render compounds 1, 5, and 6 important materials for further applications including complementary inflammation remedies and/or functional foods and nutraceuticals.

Bioactive oleanane-type saponins from the rhizomes of Anemone taipaiensis

Investigation of the n-BuOH extract of the rhizomes of Anemone taipaiensis led to the isolation of five new oleanane-type triterpenoid saponins (1-5), together with seven known saponins (6-12). Their structures were determined by the extensive use of (1)D and (2)D NMR experiments along with ESIMS analyses and acid hydrolysis. The aglycone of 1, 2 and 4 was determined as siaresinolic acid, which was reported in this genus for the first time. The cytotoxicities of the saponins 1-12, prosapogenins 4a, 5a, 10a-12a and sapogenins siaresinolic acid (SA), oleanolic acid (OA), hederagenin (HE) were evaluated against five human cancer cell lines, including HepG2, HL-60, A549, HeLa and U87MG. The monodesmosidic saponins 6-8, 5a, 10a-12a and sapogenins SA, OA, HE exhibited cytotoxic activity toward all cancer cell lines, with IC50 values ranging from 2.25 to 57.28 μM. Remarkably, the bisdesmosidic saponins 1-4 and 9 showed selective cytotoxicity against the U87MG cells.

Oleanane-type saponins from Anemone taipaiensis and their cytotoxic activities

Phytochemical investigation of the n-BuOH extract of the rhizomes of Anemone taipaiensis led to the isolation of three new oleanane-type triterpenoid saponins (1-3), together with four known saponins (4-7). Their structures were elucidated on the basis of spectroscopic analysis and chemical derivatization. All the compounds were isolated for the first time from A. taipaiensis. The cytotoxicity of these compounds was evaluated in five human cancer cell lines including A549 (lung carcinoma), HeLa (cervical carcinoma), HepG2 (hepatocellular carcinoma), HL-60 (promyelocytic leukemia), and U87MG (glioblastoma). The monodesmosidic saponin 4 exhibited cytotoxic activity toward all cancer cell lines, with IC50 values ranging from 6.42 to 18.16 μM. In addition, the bisdesmosidic saponins 1 and 7 showed selective cytotoxicity against the U87MG cells.

Oleanane glycosides from Astragalus tauricolus: isolation and structural elucidation based on a preliminary liquid chromatography-electrospray ionization tandem mass spectrometry profiling

As a part of our ongoing research for bioactive compounds from Turkish Astragalus species, the investigation of Astragalus tauricolus has been carried out. An approach based on HPLC-ESIMS(n) experiments has been used to profile the triterpene glycosides occurring in the butanol extract of the whole plant. On the basis of the results of the online screening by HPLC-ESIMS(n), 22 oleanane-type triterpene glycosides, including ten compounds never reported before, were isolated, and their structures were established by the extensive use of 1D and 2D-NMR experiments along with ESIMS and HRMS analysis. Noteworthy, cycloartane-type triterpene glycosides, the main constituents of Astragalus spp., were not found. This peculiar feature characterizes a very limited group of Astragalus spp. The antiproliferative activity of the isolated compounds 1-12, 15, 17-19 was evaluated against a small panel of cancer cell lines. Only compound 11 showed an IC(50) of 22 μM against human leukemia cell line (U937). The other tested compounds, in a range of concentrations between 1 and 50 μM, did not cause any significant reduction of the cell number.

Pyrrole and furan oligoglycosides from the starfish Asterina batheri and their inhibitory effect on the production of pro-inflammatory cytokines in lipopolysaccharide-stimulated bone marrow-derived dendritic cells

Three new pyrrole oligoglycosides, astebatheriosides A-C (1-3), and a new furan oligoglycoside, astebatherioside D (4), were isolated from the starfish Asterina batheri by various chromatographic methods. Their structures were elucidated by spectroscopic and chemical methods. Compounds 2, 3, and 4 moderately inhibited IL-12 p40 production in lipopolysaccharide (LPS)-stimulated bone marrow-derived dendritic cells (BMDCs) with IC50 values of 36.4, 31.6, and 22.8μM, respectively.

Saponins from Astragalus hareftae (NAB.) SIRJ

Four cycloartane- (hareftosides A-D) and oleanane-type triterpenoids (hareftoside E) were isolated from Astragalus hareftae along with fifteen known compounds. Structures of the compounds were established as 3,6-di-O-β-D-xylopyranosyl-3β,6α,16β,24(S),25-pentahydroxycycloartane, 3,6,24-tri-O-β-D-xylopyranosyl-3β,6α,16β,24(S),25-pentahydroxycycloartane, 3-O-β-D-xylopyranosyl-3β,6α,16β,25-tetrahydroxy-20(R),25(S)-epoxycycloartane, 16-O-β-D-glucopyranosyl-3β,6α,16β,25-tetrahydroxy-20(R),24(S)-epoxycycloartane, 3-O-[β-D-xylopyranosyl-(1→2)-O-β-D-glucopyranosyl-(1→2)-O-β-D-glucuronopyranosyl]-soyasapogenol B by the extensive use of 1D- and 2D-NMR experiments along with ESI-MS and HR-MS analyses.

Revised structures of avenacosides A and B and a new sulfated saponin from Avena sativa L

The revised structures of avenacosides A and B and a new sulfated steroidal saponin isolated from grains of Avena sativa L. were elucidated. Their structures and complete NMR assignments are based on 1D and 2D NMR studies and identified as nuatigenin 3-O-{α-L-rhamnopyranosyl-(1→2)-[β-D-glucopyranosyl-(1→4)]-β-D-glucopyranoside}-26-O-β-D-glucopyranoside (1), nuatigenin 3-O-{α-L-rhamnopyranosyl-(1→2)-[β-D-glucopyranosyl-(1→3)-β-D-glucopyranosyl-(1→4)]-β-D-glucopyranoside}-26-O-β-D-glucopyranoside (2), and nuatigenin 3-O-{α-L-rhamnopyranosyl-(1→2)-[β-D-6-O-sulfoglucopyranosyl-(1→4)]-β-D-glucopyranoside}-26-O-β-D-glucopyranoside (3).

Two New Asterosaponins from the Far Eastern Starfish Lethasterias fusca

Two new asterosaponins, lethasteriosides A (1) and B (2), were isolated along with previously known thornasteroside A (3), anasteroside A (4), and luidiaquinoside (5) from the ethanolic extract of the Far Eastern starfish Lethasterias fusca. The structures of the new compounds were elucidated by extensive NMR and ESIMS techniques, and chemical transformations. Compounds 1 and 3–5 did not show any apparent cytotoxicity against cancer cell lines T-47D, RPMI-7951, and HCT-116, but glycoside 1, at concentration of 20 μM, demonstrated considerable inhibition of the T-47D (97%), RPMI-7951 (90%) and HCT-116 (90%) cell colony formations in a soft agar clonogenic assay.

HPLC-ESIMS(n) profiling, isolation, structural elucidation, and evaluation of the antioxidant potential of phenolics from Paepalanthus geniculatus

The methanol extract of the flowers of Paepalanthus geniculatus Kunth. showed radical-scavenging activity in the TEAC assay. An analytical approach based on HPLC-ESIMS(n) was applied to obtain the metabolite profile of this extract and led to the rapid identification of 19 polyphenolic compounds comprising flavonoids and naphthopyranones. The new naphthopyranone (10, 16), quercetagetin (1, 5, 7, 13), and galetine derivatives (9, 11, 17, 19), and a flavonol glucoside cyclodimer in the truxillate form (12), were identified. Compounds 2, 6, and 7 showed the highest antioxidant capacity and ability to affect the levels of intracellular ROS in human prostate cancer cells (PC3).

Cycloartane glycosides from Astragalus stereocalyx Bornm

Six cycloartane-type triterpene glycosides were isolated from Astragalus stereocalyx along with six known cycloartane-type glycosides. Their structures were established by the extensive use of 1D and 2D-NMR experiments along with ESIMS and HRMS analysis. Three compounds are based on an aglycon characterized by the occurrence of an unusual hydroxyl group at position 20, whereas three other compounds are based on cycloasgenin C as aglycon, so far reported from Astragalus spp. All the compounds were tested for their cytotoxic activity against a number of cancer cell lines. One compound exhibited activity versus human cervical cancer (Hela) with an IC(50) value = 10 μM.

Triterpene saponins from Cyclamen hederifolium

Five triterpene saponins never reported before, hederifoliosides A-E, and four known triterpene saponins were isolated from the tubers of Cyclamen hederifolium. The structures of hederifoliosides A-E were determined as 3β,16α-dihydroxy-13β,28-epoxyolean-30-oic acid 3-O-{[β-D-glucopyranosyl-(1 → 2)-O]-β-D-xylopyranosyl-(1 → 2)-O-β-D-glucopyranosyl-(1 → 4)-O-α-L-arabinopyranoside}, 3β,16α-dihydroxy-13β,28-epoxyolean-30-oic acid 3-O-{[β-D-glucopyranosyl-(1 → 2)-O]-β-D-xylopyranosyl-(1 → 2)-O-[β-D-glucopyranosyl-(1 → 3)]-O-β-D-glucopyranosyl-(1 → 4)-O-α-L-arabinopyranoside}, 3β,16α-dihydroxy-13β,28-epoxyolean-30-al 3-O-{[β-D-glucopyranosyl-(1 → 2)-O]-β-D-xylopyranosyl-(1 → 2)-O-[β-D-glucopyranosyl-(1 → 3)]-O-[β-D-glucopyranosyl-(1 → 6)]-O-β-D-glucopyranosyl-(1 → 4)-O-α-L-arabinopyranoside}, 30-O-β-D-glucopyranosyl-(1 → 2)-O-β-D-glucopyranosyl-3β,16α,30-trihydroxyolean-12-en-28-al 3-O-{[β-D-glucopyranosyl-(1 → 2)-O]-β-D-xylopyranosyl-(1 → 2)-O-β-D-glucopyranosyl-(1 → 4)-O-α-L-arabinopyranoside}, 30-O-β-D-glucopyranosyl-(1 → 2)-O-β-D-glucopyranosyl-3β,16α,28,30-tetrahydroxyolean-12-en 3-O-{[β-D-glucopyranosyl-(1 → 2)-O]-β-D-xylopyranosyl-(1 → 2)-O-[β-D-glucopyranosyl-(1 → 3)]-O-β-D-glucopyranosyl-(1 → 4)-O-α-L-arabinopyranoside}, by a combination of one- and two-dimensional NMR techniques, and mass spectrometry. The cytotoxic activity of the isolated compounds was evaluated against a small panel of cancer cell lines including Hela, H-446, HT-29, and U937. None of the tested compounds, in a range of concentrations between 1 and 50 μM, caused a significant reduction of the cell number.

Chemical constituents and bioactivities of starfish

Starfish have been the research topic in many chemical and pharmacological laboratories due to their complex secondary metabolites and diverse bioactivities. The aim of this review is to provide an up-to-date review on the chemistry and bioactivity of compounds isolated from all kinds of starfish to illustrate the chemodiversity and biological significance of these constituents, along with their geographical distribution where it is discernible.

Cycloartane glycosides from Astragalus aureus

Eight cycloartane-type triterpene glycosides (1-8) were isolated from Astragalus aureus Willd along with ten known cycloartane-type glycosides (9-18). Their structures were established by the extensive use of 1D and 2D-NMR experiments along with ESIMS and HRMS analyses. Compounds 1-5 are cyclocanthogenin glycosides, whereas compounds 6-8 are based on cyclocephalogenin as aglycon, more unusual in the plant kingdom, so far reported only from Astragalus spp. Moreover, for the first time monoglycosides of cyclocanthogenin (5) and cyclocephalogenin (7, 8) are reported. All of the compounds tested for their cytotoxic activities against a number of cancer cell lines. Among the compounds, only 8 exhibited activity versus human breast cancer (MCF7) at 45 μM concentration.

Polyhydroxysteroidal glycosides from the starfish Anthenea chinensis

Ten new polyhydroxysteroidal glycosides, anthenosides B-K (2-11), were isolated from the ethanol extract of the starfish Anthenea chinensis. Their structures were elucidated by extensive spectroscopic studies and chemical evidence. The unprecedented carbohydrate chain 6-O-methyl-beta-d-galactofuranosyl-(1-->3)-(6-O-methyl-beta-d-galactofuranose) was present in all the compounds except compounds 10 and 11. Compounds 5, 7, a mixture of 8 and 9, and a mixture of 10 and 11 showed inhibitory activity against human tumor K-562 and BEL-7402 cells. Furthermore, the mixture of 10 and 11 also exhibited cytotoxicity against human tumor U87MG cells and promoted tubulin polymerization.

New Polar Steroids from Starfish

A short review concerning new polar steroids isolated from starfish with 75 citations is given. This review covers the literature published from 2001 through 2007. The emphasis is on new structures, together with their relevant biological activities, source organisms, and localities of collections.

Asterosaponins from the starfish Culcita novaeguineae and their bioactivities

Bioassay-guided fractionation of the n-BuOH extract of the starfish Culcita novaeguineae resulted in the isolation of one new sulfated steroidal glycoside (asterosaponin) (1), along with three known asterosaponins, thornasteroside A (2), marthasteroside A(1) (3) and regularoside A (4), as active compounds causing morphological abnormality of Pyricularia oryzae mycelia. Their structures were elucidated by extensive spectral studies and chemical evidences. All the saponins showed moderate cytotoxicity against cancer cell lines K-562 and BEL-7402.

Marine natural products

This review covers the literature published in 2003 for marine natural products, with 619 citations (413 for the period January to December 2003) referring to compounds isolated from marine microorganisms and phytoplankton, green algae, brown algae, red algae, sponges, coelenterates, bryozoans, molluscs, tunicates and echinoderms. The emphasis is on new compounds (656 for 2003), together with their relevant biological activities, source organisms and country or origin. Biosynthetic studies or syntheses that lead to the revision of structures or stereochemistries have been included (78), including any first total syntheses of a marine natural product.