Two new asterosaponins from the antarctic starfish Diplasterias brucei. Structures and cytotoxic activities

Two new asterosaponins, diplasteriosides A and B, with the same oligosaccharide chains beta-D-Fucp-(1-->2)-beta-D-Galp-(1-->4)-[beta-D-Quip-(1-->2)]-beta-D-Quip-(1-->3)-beta-D-Quip-(1-->, linked to C6 of known genins, 3-O-sulfates of thornasterols A and B, respectively, were isolated along with the previously known asteriidoside A from the Antarctic starfish Diplasterias brucei. The structures of new compounds were elucidated by spectroscopic methods (mainly 2D NMR and mass spectrometry). The cytotoxicity of isolated asterosaponins against human colon cancer cell line HCT-116, human breast cancer cell line T-47D, and human melanoma cancer cell line RPMI-7951 was investigated.     

Structures and cytotoxic activities of two new asterosaponins from the antarctic starfish <Emphasis Type="Italic">Diplasterias brucei</Emphasis>

Two new asterosaponins, diplasteriosides A and B, bearing the same β-D-Fucp-(1→2)-β-D-Galp-(1→4)-[β-D-Quip-(1→2)]-β-D-Quip-(1→3)-β-D-Quip-(1→ oligosaccharide chains linked to the C6 atom of the known genins, 3-O-sulfates of thornasterols A and B, respectively, were isolated from the Antarctic Diplasterias brucei starfish along with the previously known asteriidoside A. The structures of the new compounds were elucidated by two-dimensional NMR spectroscopy and mass spectrometry. Cytotoxicities of the isolated asterosaponins against the human colon cancer HCT-116, human breast cancer T-47D cell line, and human melanoma cancer RPMI-7951 cell lines were studied.     

Chemical constituents of the rhizomes of Hedychium coronarium and their inhibitory effect on the pro-inflammatory cytokines production LPS-stimulated in bone marrow-derived dendritic cells

The rhizomes of Hedychium coronarium have been used for the treatment of inflammation, skin diseases, headache, and sharp pain due to rheumatism in traditional medicine. From this plant, three new labdane-type diterpenes 1–3, named coronarins G–I as well as seven known 4–10, coronarin D, coronarin D methyl ether, hedyforrestin C, (E)-nerolidol, β-sitosterol, daucosterol, and stigmasterol were isolated. Their chemical structures were elucidated by mass, 1D- and 2D-nuclear magnetic resonance spectroscopy. They were evaluated for inhibitory effects on lipopolysaccharide-stimulated production of pro-inflammatory cytokines in bone marrow-derived dendritic cells. Among of them, compounds 1, 2, and 6 were significant inhibitors of LPS-stimulated TNF-α, IL-6, and IL-12 p40 productions with IC₅₀ ranging from 0.19 ± 0.11 to 10.38 ± 2.34 μM. The remains of compounds showed inactivity or due to cytotoxicity. These results warrant further studies concerning the potential anti-inflammatory benefits of labdane-type diterpenes from H. coronarium.     

Triterpenoid saponins with antifeedant activities from stem bark of Catunaregam spinosa (Rubiaceae) against Plutella xylostella (Plutellidae)

Seven triterpenoid saponins, including four new compounds, catunarosides A–D (1–4), and three known compounds, swartziatrioside (5), aralia-saponin V (6), araliasaponin IV (7) were isolated from the stem bark of Catunaregam spinosa, a Chinese mangrove associate. Their structures were elucidated on the basis of their spectral data and hydrolysis experiments. The antifeedant activities of compounds 1–7 against Plutella xylostella were also evaluated.     

Constituents from Chimonanthus praecox (wintersweet)

One new (1) and seven (2–8) known sesquiterpenoids, four dimeric tryptamine-related alkaloids (9–12) and six glycosides (13–18) were isolated from the fruits and leaves of Chimonanthus praecox (wintersweet). Based on its spectroscopic data, the new structure of compound 1, an oppositane-type sesquiterpenoid, was elucidated to be the C-4 epimer of bullatantriol (2). All isolated compounds were evaluated for their cytotoxicities against a small panel of human cancer cell lines, and only the chimonanthine-type alkaloids (10–12) were found to have cytotoxic effects against gastric carcinoma NUGC3 and hepatocarcinoma SNU739 cancer cells, with IC₅₀ values ranging from 10.3 to 19.7 μM.     

Antidiabetic activity of phenolic compounds from Pecan bark in streptozotocin-induced diabetic rats

The n-butanol fraction (BF) of bark of Pecan tree, Carya illinoinensis (Wangenh) K. Koch (Juglandaceae) afforded two new flavonol methyl ether: caryatin-3′ sulfate (6) and caryatin-3′ methyl ether-7-O-β-d-glucoside (7) while five known phenolics (1–5) were isolated from its ethyl acetate fraction (EAF). The structures of isolated compounds were established based on 1D and 2D NMR spectroscopy. The isolated compounds were investigated for their hypoglycaemic, antioxidant as well as the aldose reductase (AR) inhibitory effect in lenses of streptozocin diabetic rats. All the isolated compounds showed significant hypoglycaemic and antioxidant activities, except 5 and 6. A marked AR-inhibitory effect was identified for compounds 2, 3 and 7.     

Brominated aliphatic hydrocarbons and sterols from the sponge Xestospongia testudinaria with their bioactivities

Four brominated aliphatic hydrocarbons (1–4), including a novel brominated ene-tetrahydrofuran named as mutafuran H (1), and five sterols (5–9) were isolated from the South China Sea sponge Xestospongia testudinaria. The structure of 1 was determined on the basis of NMR (¹H, ¹³C NMR, HSQC, HMBC, ¹H–¹H COSY, and NOESY), MS, and optical rotation analysis. Known compounds were identified by comparison of their NMR data with those reported in the literature. Compounds 1–4, and 6–9 were evaluated for their toxicity against Artemia salina larvae, and anti-acetylcholinesterase activity.     

Cytotoxic and haemolytic steroidal glycosides from the Caribbean sponge Pandaros acanthifolium

Six new steroidal saponins, pandarosides K–M (1–3) and their methyl esters (4–6), were isolated as minor components, after a careful chemical reinvestigation of the Caribbean sponge Pandaros acanthifolium. Their structures were established on the basis of spectroscopic analyses and comparison with the data obtained from previous metabolites of this family. All new compounds showed moderate to weak activity against four parasitic protozoa. Additionally, these compounds and previously reported pandarosides and acanthifoliosides were tested on three human tumour cell lines, and their haemolytic and liposome permeabilizing activity were assessed. Two pandarosides exhibited moderate to strong cytotoxic effect, while three acanthifoliosides showed strong haemolytic activity.     

Bis(monoterpenoid) indole alkaloid glucosides from Uncaria hirsuta

One novel bis(monoterpenoid) indole alkaloid glucoside, hirsutaside D (1), along with three known compounds, bahienoside A (2), bahienoside B (3) and neonaucleoside B (4), were isolated from the leaves of U. hirsuta. The structure of compound 1 was elucidated on the basis of extensive spectroscopic data analysis and chemical means. Characterization of compounds 2–4 was based on spectral analysis and comparison with the literature. Their cytotoxic effects on four human tumor cell lines were examined.     

Cytotoxic activity of withanolides isolated from Tunisian Datura metel L

Withanolide-type steroids, withametelin Q (1) and 12α-hydroxydaturametelin B (2) along with three known withanolides, were isolated from leaves of Datura metel L. (Solanaceae). The respective structures, characterized mainly by NMR spectroscopy, were identified as (20R,22R,24R)-21,24-epoxy-1α,3β-dihydroxywitha-5,25(27)-dienolide-3-O-β-d-glucopyranoside (1) and (20R,22R,24R)-12α,21,27-trihydroxy-1-oxowitha-2,5,24-trienolide-27-O-β-d-glucopyranoside (2). The cytotoxicity of isolated compounds was evaluated against human lung carcinoma cells (A549) and human colorectal adenocarcinoma cells (DLD-1), respectively. Compound 2 exhibited cytotoxicity against A549 and DLD-1 cell lines, with IC₅₀ values of 7 and 2.0 μM, respectively. However, for compounds 6 and 7, cytotoxicities were higher against DLD-1 cells with IC₅₀ values of 0.6 and 0.7 μM. Both compounds blocked the cell cycle in the S-phase and induced apoptosis.     

Diabetic nephropathy-related active cyclic peptides from the roots of Brachystemma calycinum

Three new cyclic peptides, namely duanbanhuains A–C (1–3), were isolated from the roots of Brachystemma calycinum which is a traditional medicine used to treat rheumatic diseases. Their structures were identified by means of a suite of MS and NMR experiments. These compounds were purposely evaluated for their inhibitory effects on the release of MCP-1, IL-6, collagen IV and reactive oxygen species (ROS) against high-glucose-stimulated mesangial cells. The results showed that compounds 1 and 2 exhibited potent inhibition on the production of IL-6, collagen IV and ROS at the concentration of 10 μM.     

New lanostane-type triterpenoids, inonotsutriols D, and E, from Inonotus obliquus

Two new lanostane-type triterpenoids, inonotsutriols D (1) and E (2), were isolated from the sclerotia of Inonotus obliquus (Pers.: Fr.) Pil. (Japanese name: kabanoanatake; Russian name: chaga). Their structures were determined to be lanost-8-ene-3β,22R,24R-triol (1) and lanost-8-ene-3β,22R,24S-triol (2) on the basis of spectral data, including 2D NMR analysis. In addition, major compounds, inotodiol (3), trametenolic acid (4), 3β-hydroxylanosta-8,24-dien-21-al (5), 21-hydroxylanosterol (6), inonotsuoxide A (7) and inonotsuoxide B (8) were identified, and all compounds, except 2, were evaluated for their cancer cell growth inhibitory activity against P388, HL-60, L1210 and KB cell lines.     

Bis(oxyphenylene)benzimidazoles: a novel class of anti-Plasmodium falciparum agents

A small library of 26 2,2′-[alkane-α,ω-diylbis(oxyphenylene)]bis-1H-benzimidazoles has been prepared and evaluated against Giardia intestinalis, Entamoeba histolytica, Trypanosoma brucei rhodesiense, Trypanosoma cruzi, Leishmania donovani, and Plasmodium falciparum. Among the tested compounds, eight derivatives (17, 19, 20, 24, 27, 30, 32 and 35) exhibited an anti-Plasmodium falciparum activity characterized by IC₅₀ values in the range of 180–410 nM (0.11–0.21 μg/mL) and selectivity indexes (IC₅₀ rat skeletal myoblasts L6 cells vs IC₅₀P. falciparum K1 strain) varying between 92 and more than 450. Two of the eight novel drug leads, namely compounds 19 and 32, were also active against G. intestinalis and L. donovani with selectivity indexes of 122 and >164 respectively.     

Limonoids from the fruits of Melia toosendan

Four (1–4) new and seven known limonoids were isolated from the EtOH extract of the fruits of Melia toosendan. The structures of the new compounds were established on the basis of spectroscopic methods to be 12-O-methyl-1-O-deacetylnimbolinin B (1), 12-O-methy-1-O-tigloyl-1-O-deacetylnimbolinin B (2), 12-O-ethylnimbolinin B (3), and 1-O-cinnamoyl-1-O-debenzoylohchinal (4). Additionally, two new tirucallane-type triterpenoids, named meliasenins S (5) and T (6), were obtained from the same fractions during purification of the limonoids.     

Four new phenolic diglycosides from the roots of Illicium oligandrum

Four new phenolic diglycosides (1–4), named illoliganoside A–D, and three known glycosides (5–7), were isolated from the roots of Illiciumoligandrum. The structures of the new diglycosides were determined on the basis of HRMS, NMR spectroscopic, and chemical methods. The anti-inflammatory and cytotoxic activities for 1–7 were evaluated.     

Pitipeptolides C-F, antimycobacterial cyclodepsipeptides from the marine cyanobacterium Lyngbya majuscula from Guam

Pitipeptolides A (1) and B (2) are cyclic depsipeptides isolated from the marine cyanobacterium Lyngbya majuscula from Piti Bomb Holes, Guam. Additional analogues have now been isolated by revisiting larger collections of the same cyanobacterium. The four identified analogues, pitipeptolides C–F (3–6), are the tetrahydro analogue (3), an analogue with a lower degree of methylation (4) as well as two homologues (5 and 6) of pitipeptolide A. Their structures were elucidated using 2D NMR experiments, chiral HPLC analysis and comparison with pitipeptolide A. The identified analogues showed weaker cytotoxic activities compared to the two major parent compounds, pitipeptolides A (1) and B (2), against HT-29 colon adenocarcinoma and MCF7 breast cancer cells. On the other hand, pitipeptolide F (6) was the most potent pitipeptolide in a disc diffusion assay against Mycobacterium tuberculosis. The latter finding suggests that the structure of pitipeptolides could be optimized for selective antibacterial activity.     

New triterpenoid saponins from Patrinia scabiosaefolia

Phytochemical investigation of the methanol extract from the whole plants of Patrinia scabiosaefolia Fisch. resulted in the isolation of four new triterpenoid saponins (1–4) along with six known compounds (5–10). On the basis of spectroscopic and chemical methods, the structures of the new compounds were established as 3-O-β-d-xylopyranosyl-(1→3)-α-l-rhamnopyranosyl-(1→2)-β-d-xylopyranosyl-12β,30-dihydroxy-olean-28,13β-olide (1), 3-O-α-l-rhamnopyranosyl-(1→2)-β-d-xylopyranosyl-12β,30-dihydroxy-olean-28,13β-olide (2), 3-O-β-d-xylopyranosyl-(1→2)-β-d-glucopyranosyl-12β, 30-dihydroxy-olean-28,13β-olide (3), and 3-O-β-d-glucopyranosyl-(1→4)-β-d-xylopyranosyl-(1→3)-α-l-rhamnopyranosyl-(1→2)-β-d-xylopyranosyl-oleanolic acid 28-O-β-d-glucopyranoside (4), respectively. Compounds 1–3 possess a novel 12β,30-dihydroxy-olean-28,13β-lactone aglycone and a 12β-hydroxy substituent that is rarely found in this kind of triterpenoid saponin.     

Characterization of cyclic β-glucans of Bradyrhizobium by MALDI-TOF mass spectrometry

Periplasmic, cyclic β-glucans isolated from Bradyrhizobium elkanii, Bradyrhizobium liaoningense, and Bradyrhizobium yuanmingense strains have been investigated by means of Matrix-Assisted Laser Desorption/Ionization Time-of-Flight Mass Spectrometry (MALDI-TOF MS), 1D and 2D nuclear magnetic resonance (NMR), as well as standard chemical methods. These compounds are built of 10–13 d-glucose residues. The main fractions contain molecules assembled of 12 hexose units (M_w = 1945.363 Da). Glucose monomers are linked by β-(1→3) or β-(1→6) glycosidic bonds. The ratio of β-(1→3) to β-(1→6) linked glucose is approximately 1:2. Moreover, methylation analysis demonstrated the presence of terminal, non-reducing, as well as branched (i.e., 3- and 6-substituted) glucoses. Thus, the basic structure of the investigated compounds is similar to that of periplasmic oligosaccharides from Bradyrhizobium japonicum and Azorhizobium caulinodans strains. The analyzed cyclic β-glucans are substituted by phosphocholine (PC) (one or two residues per ring) and highly decorated with acetate and succinate. The substituents are arranged diversely in the population of cyclic β-glucan molecules. The concentrations of cyclic β-glucans in Bradyrhizobium periplasmic space are osmotically regulated and increase in response to a decrease of medium osmolarity.