Justiciosides E-G, triterpenoidal glycosides with an unusual skeleton from Justicia betonica

Three new triterpenoidal glucosides, justiciosides E, F and G, were isolated from the aerial portion of Justicia betonica. Their structures were established through chemical and spectroscopic analyses, and showed an unusual A-nor-B-homo oleanan-12-ene skeleton type for the aglycone moiety as A-nor-B-homo-oleanan-10,12-diene-3β,11α,28-triol 28-O-β-d-glucopyranosyl-(1→2)-β-d-glucopyranoside, A-nor-B-homo-oleanan-10,12-diene-3β,11α,28-triol 28-O-β-d-glucopyranosyl-(1→2)-β-d-glucopyranosyl-(1→2)-β-d-glucopyranoside, and 11α-methoxy-A-nor-B-homo-oleanan-10,12-diene-3β,11α,28-triol 28-O-β-d-glucopyranosyl-(1→2)-β-d-glucopyranosyl-(1→2)-β-d-glucopyranoside, respectively.     

Tripenoid glycosides of alfalfa. VII. Medicosides E and F

Two hederagenin glycosides — medicosides E and F — have been isolated from the roots ofMedicago sativa L. (Leguminosae). Medicoside E has the structure of hederagenin 28-O-β-D-glucopyranoside 3-O-[O-β-G-glucopyranosyl-(1→3)-β-D-xylopyranoside]. Medicoside F has the structure of hederagenin 28-O-β-D-glucopyranoside 3-O-[O-β-D-glucopyranosyl-(1→2)-α-L-arabinopyranoside].     

A new triterpene and a saponin from Centella asiatica

A new triterpene and a saponin,named 2α,3β,23-trihydroxyurs-20-en-28-oic acid(1)and 2α,3β,23-trihydroxyurs-20-en-28-oic acid O-α-L-rhamnopyranosyl-(1→4)-O-β-D-glucopyranosyl-(1→6)-O-β-D-glucopyranosyl ester(2),have been isolated from the aerial part of Centella asiatica.Their structures were elucidated by spectral methods,including 2D-NMR spectra.     

Steroid alcohols from the ascidianHalocynthia aurantium

The total sterols have been isolated fromHalocynthia aurantium by column chromatography on silica gel. The following steroid alcohols have been identified in it with the aid of GLC, GLC-MS, and¹H NMR: 5α-cholestan-3β-ol, 24ξ-methylcholestan-3β-ol, 24ξ-ethylcholestan-3β-ol, 4ξ-methyl-24ξ-ethyl-5α-cholestan-3β-ol, cholest-5-en-3β-ol, 24ξ-methylcholest-5-en-3β-ol, 24ξ-ethylcholes-5-en-3β-ol, 5α-cholest-22-en-3β-ol, 24-nor-5α-cholest-22-en-3β-ol, cholesta-5,22-dien-3β-ol, 24ξ-methylcholesta-5,22-dien-3β-ol, 24-norcholesta-5,22-dien-3β-ol, 24-ethylcholesta-5,24(28)-dien-3β-ol, and 24-methylcholesta-5,24(28)-dien-3β-ol.     

An appraisal of Luffa aegyptiaca extract and its isolated triterpenoidal saponins in Trichinella spiralis murine models

Trichinella spiralis is an intestinal and tissue parasitic nematode, emerging and re-emerging causative agent of a serious foodborne parasitic infection. This study aimed to evaluate the effect of Luffa aegyptiaca leaf extract and its triterpene glycosides on the intestinal and muscle stages of T. spiralis infection in vitro and in vivo. Phytochemical investigations of the extract led to the isolation of five compounds, namely (1) 3-O-β-d-glucopyranosyl-16-O-β-hydroxyolea12-en 23, 28-β-d-diglucopyranoside ester, (2) 3β-hydroxylolea12-en-28-oic acid (Oleanoic acid), (3) oleanolic acid 3-O-α-l-rhamnopyranosyl-(1 → 4)-β-d-glucopyranoside, (4) 3-O-β-d-glucopyranosyl-28-β-d-glucopyranosyl oleanolate, and (5) stigmast-5, 22-dien-3-O-β-d-glucopyrano-side. Moreover, the in vitro study showed marked degeneration and destruction of adult worms and larval teguments with tested drugs. Also, in the in vivo study, mice were divided into six groups; group I: infected and untreated, group II: received leaf extract as prophylaxis, group III: infected and treated with leaf extract, group IV: treated with compound (4), group V: treated with compound (1), and group VI: treated with albendazole. Furthermore, the treatment efficacy was assessed by the adult and total larval counts, histopathological study of the small intestinal and muscle tissues, and immunohistochemical staining of CD34 in muscles. The results revealed a significant reduction of total adult and larval counts in prophylactic and treated groups compared to the positive control group, with a reduction of total adult count by 63.48% and 74.4% in compound (1) and compound (4) treated groups, respectively. Also, a reduction was detected in larval counts by 36.5%, and 93.6% in compound (1) and compound (4) treated groups during both the muscular and intestinal phases, respectively.Additionally, histopathological examination of the small intestine and muscles showed marked improvement with a reduction in the inflammatory infiltrates in treated groups. CD34 expressions were reduced in treated groups with more reduction in compound (4) treated group. In conclusion, this study implies that L. aegyptiaca leaf extract and its tested triterpene glycosides might be used for anti-trichinellosis treatments.     

Withasteroids ofPhysalis. V. A study of the1H and13C NMR spectra of the withasteroids visconolide and 28-hydroxywithaperuvin C

The PMR and¹³C NMR spectra of new withasteroids — visconolide and 28-hydroxywithaperuvin C, isolated fromPhysalis viscosa L. — have been investigated. A detailed analysis of the spectral characteristics obtained is given. For visconolide is proposed the structure of 4β,12α,17β,28-pentahydroxy-1-oxo-5β, 6β-epoxy-22R-witha-2,24-dienolide, and for 28-hydroxywithaperuvin C that of 6β,14α,17β,20R, 28-pentahydroxy-l-oxo-22R-witha-2, 4, 24-trienolide.     

Triterpene saponins fromThalictrum minus. V. Structure of thalicoside B

The epigeal part ofThalictrum minus L. has yielded a new bidesmoside — thalicoside B — which has the structure of oleanolic acid 28-O-β-D-glucopyranoside 3-O-[O-α-L-rhamnopyranosyl-(1 → 2)-O-β-D-glucopyranosyl-(1 → 3)-α-L-arabinopyranoside].     

19-nor-11-Oxooleanan-12-ene and 18,19-seco-19-oxours-11,13(18)-diene triterpenes from Diospyros decandra bark

Four new triterpenes, 2α,3β-dihydroxy-19-nor-11-oxo-20-dimethylurs-12-en-24,28-dioic acid (equivalent to 2α,3β-dihydroxy-19-nor-11-oxoolean-12-en-24,28-dioic acid), 2α,3β-dihydroxy-18,19-seco-19-oxours-11,13(18)-dien-24,28-dioic acid, 2α,3β,19α-trihydroxy-11-oxours-12-en-24,28-dioic acid and 2α,3β,19α-trihydroxy-28-1′-β-d-[glucopyranosyl-(1″→6′)-glucopyranosyl]-urs-12-en-24,28-dioic acid were isolated from the methanol extract of the bark of Diospyros decandra as their acetate-methyl ester derivatives. The first two compounds represent the biosynthetic transformation products of 2α,3β,19-trihydroxyurs-24,28-dioic acid via oxidative rearrangement of ring E.     

Triterpene glycosides ofSilphium perfoliatum. III. Structure of silphioside E

A new triterpene glycoside — silphioside E — has been isolated from the epigeal part ofSilphium perfoliatum L. and its structure has been established on the basis of chemical transformations and spectral characteristics as oleanolic acid 28-0-β-D-glycopyranoside 3-0-[0-β-D-glycopyranosyl-(1 → 2)-β-D-glucopyranoside].     

Two new olean-type triterpene fatty esters from Scorzonera mongolica

Two new triterpene fatty esters, 33-tetradecanoyl moradiol 1 and 3β-dodecanoyl moradiol 2, were isolated from Scorzonera mongolica. Their structures were elucidated as 3β-tetradecanoyloxy-28-hydroxylolean-18-ene and 3β-dodecanoyl-28-hydroxyl-olean-18-ene on the basis of IR, MS, ID NMR and extensive 2D NMR spectroscopic analyses.     

Triterpene glycosides and their genins fromThalictrum foetidum. I. The structure of foetoside C

A new glycoside — foetoside C — has been isolated from the epigeal part ofThalictrum foetidum L. and, on the basis of chemical transformations and spectral characteristics its structure has been established as oleanolic acid 28-[O-α-D-glycopyranosyl-(1 → 6)-O-β-D-glucopyranoside] 3-O-[O-β-D-xylopyranosyl-(1 → 3)-O-α-L-rhamnopyranosyl-(1 → 2)-α-L-arabinopyranoside].     

A new triterpenoid saponin from the roots of Platycodon grandiflorum

A new triterpenoid saponin, 3-O-β-D-glucopyranosyl 16-oxo-platycodigenin 28-O-β-D-apiofuranosyl-(1→3)-β-D-xylopyranosyl-(1→4)-α-L-rhamnopyranosyl-(1→2)-α-L-arabinopyra-nosyl ester, was isolated from the roots of Platycodon grandiflorum, together with three known saponins, including platycodin D, deapio platycoside E and platycoside E. The structure of the new compound, named 16-oxo-platycodin D, was elucidated on the basis of spectroscopic data.     

A facile enantioselective synthesis of (S)-N-(5-chlorothiophene-2-sulfonyl)-β,β-diethylalaninol via proline-catalyzed asymmetric α-aminooxylation and α-amination of aldehyde

A high-yielding enantioselective synthesis of the bioactive (S)-N-(5-chlorothiophene-2-sulfonyl)-β,β-diethylalaninol (1), a Notch-1-sparing γ-secretase inhibitor metabolite (with EC₅₀ = 28 nM) effective in reduction of Aβ production in vivo, has been realized starting from readily available 3-pentanone. The key steps of the synthesis are proline-catalyzed α-aminooxylation and α-amination of aldehyde; the latter contributing an overall yield of 45.2% and 98% ee.     

Structure of marsileagenin a; A new hexahydroxy triterpene from marsilea minuta linn

The crude saponin obtainable from Marsilea minuta Linn on acid hydrolysis yielded a mixture of sapogenols. The major sapogenol named Marsileagenin A was found to be a hexahydroxy triterpene of oleanene series. From a study of various spectrometric data together with chemical reactions the structure of this sapogenol has been assigned as olean-12-ene-2α, 3β, 16β, 21β, 22α, 28-hexol (1a).     

New Triterpenes from the Heartwood of Melaleuca leucadendron L.

Fourteen chemical constituents were isolated from the CHCl₃ soluble portion of the heartwood of Melaleuca leucadendron L. These compounds include β-sitosterol (1) , β-sitostenone (2) , 6-hydroxy-4,6-dimethyl-3-hepten-2-one (3) , naphthalene (4) , squalene (5) , 2α3β-dihydroxyurs-12-en-28-oic acid (6) , 3β-hydroxylup-20(29)-en-27,28-dioic acid (7) , 2α,3β-dihydroxyolean-12-en-28-oic acid (8) , 3β,23-dihydroxyolean-12-en-28-oic acid (9) , 2α,3β,23-trihydroxyolean-12-en-28-oic acid (10) , 3β-trans-p-coumaroyloxy-2α,23-dihydroxyolean-12-en-28-oic acid (11) , and three novel oleanane derivatives 23-trans-p-coumaroyloxy-2α,3β-dihydroxyotean-12-en-28-oic acid (12), 3β-trans-caffeoyloxy-2α,23-dihydroxyolean-12-en-28-oic acid (13) , and its isomer 3β-cis-caffeoyloxy-2α,23-dihydroxyolean-12-en-28-oic acid (14) , The three novel compounds were characterized as the two and three O-methylated derivatives, respectively.     

Microbial hydroxylation and glycosidation of oleanolic acid by Circinella muscae and their anti-inflammatory activities

Biotransformation of oleanolic acid (OA) by Circinella muscae AS 3.2695 was investigated. Nine hydroxylated and glycosylated metabolites (1–9) were obtained. Their structures were elucidated as 3β,7β-dihydroxyolean-12-en-28-oic acid (1), 3β,7β,21β-trihydroxyolean-12-en-28-oic acid (2), 3β,7α,21β-trihydroxyolean-12-en- 28-oic acid (3), 3β,7β,15α-trihydroxyolean-12-en-28-oic acid (4), 7β,15α-dihydroxy- 3-oxo-olean-12-en-28-oic acid (5), 7β-hydroxy-3-oxo-olean-12-en-28-oic acid (6), oleanolic acid-28-O-β-D-glucopyranosyl ester (7), 3β,21β-dihydroxyolean-12-en-28- oic acid-28-O-β-D-glucopyranosyl ester (8), and 3β,7β,15α-trihydroxyolean-12-en- 28-oic acid-28-O-β-D-glucopyranosyl ester (9) by spectroscopic analysis. Among them, compounds 4 and 9 were new compounds. In addition, anti-inflammatory activities were assayed and evaluated for the isolated metabolites. Most of the metabolites exhibited significant inhibitory activities on lipopolysaccharides-induced NO production in RAW 264.7 cells.     

Soil bacterial hydrolysis leading to genuine aglycone—VIII : Structures of a genuine sapogenol protobassic acid and a prosapogenol of seed kernels of Madhuca longifolia L.

By virtue of the soil bacterial hydrolysis method, a genuine sapogenol named protobassic acid was obtained from the saponins of seed kernels of Madhuca longifolia L. (Sapotaceae), and the structure has been established as 2β, 3β, 6β, 23-tetrahydroxy-olean-12-en-28-oic acid (2a). In addition, the structure of a prosapogenol designated as Mi-glycoside I, which was isolated concurrently during the above microbiological procedure, has been elucidated as 3-0-β-d-glucopyranosyl-protobassic acid (3a). It has been suggested that protobassic acid (2a) may be a common sapogenol of several sapotaceous plants in place of hitherto approved bassic acid (1a).     

Concentration Effect,Structural Properties,and Driving Force on Aβ28 Dimerization with and without Zn2+ Cooperation: Learning from Replica Exchange Sampling**

Zn²⁺ is a very important factor in promoting the formation of amyloid beta (Aβ) aggregates and amyloid plaques. The Zn²⁺-bound Aβ species generate amorphous or low molecular-weight oligomers. However, it is a lack of studies to approach the starting structural features (dimerization) in Aβ nucleation processes with and without Zn²⁺, which is the key point in understanding Zn²⁺-induced nucleation mechanisms. To better understand the effect of concentration, structural properties, and the driving force, 14 independent replica exchange molecular dynamics simulations were performed in Aβ₂₈ dimerization with and without Zn²⁺ (zAβ₂₈) cooperation. Our scanning results show that the aggregation propensity is easier in Aβ₂₈-Aβ₂₈ and Aβ₂₈-zAβ₂₈ systems than zAβ₂₈-zAβ₂₈ system. In binding property, the Aβ₂₈-Aβ₂₈ model (−61.5 kcal mol⁻¹) is stronger than zAβ₂₈-zAβ₂₈ (−26.6 kcal mol⁻¹) and Aβ₂₈-zAβ₂₈ (−7.24 kcal mol⁻¹) models. Further analysis confirmed that H13 and H14 residues play specific roles in the three systems. The key point is the orientation of N atom of the imidazole ring in histidine residues. Furthermore, we discovered different driving forces for each system. Our current study contributes to the understanding of how the Aβ₂₈ dimer interacts with Zn²⁺, which could lead to new insights into Zn²⁺-induced nucleation mechanisms.     

Molecular dynamic studies of amyloid-beta interactions with curcumin and Cu<Superscript>2+</Superscript> ions

Amyloid-beta (Aβ) peptide readily forms aggregates that are associated with Alzheimer’s disease. Transition metals play a key role in this process. Recently, it has been shown that curcumin (CUA), a polyphenolic phytochemical, inhibits the aggregation of Aβ peptide. However, interactions of Aβ peptide with metal ions or CUA are not entirely clear. In this work, molecular dynamics (MD) simulations were carried out to clear the nature of interactions between the 42-residue Aβ peptide (Aβ-42) and Cu²⁺ ions and CUA. Altogether nine different models were investigated, and more than 2 µs of the simulation data were analyzed. The models represent the possible modes of arrangement between Aβ-42 and Cu²⁺ ions and CUA, respectively, and were used to shed light on the Aβ-42 conformational behavior in the presence of Cu²⁺ ions and CUA molecules. Obtained data clearly showed that the presence of a CUA molecule or a higher concentration of copper ions significantly affect the conformational behavior of Aβ-42. Calculations showed that the change of the His13 protonation state (Aβ(H13δ)-Cu²⁺, Aβ(H13δ)-Cu²⁺ -CUA models) leads to higher occurrence of the Asp23-Lys28 salt bridge. Analyzes of trajectories revealed that C-terminal β-sheet structures occurred significantly less frequently, and CUA promoted the stabilization of the α-helical structure. Further, calculations of the Aβ-42 complex with CUA and Cu²⁺ ions showed that CUA can chelate the Cu²⁺ ion and directly interact with Aβ, which may explain why CUA acts as an inhibitor of Aβ aggregation.     

27-Nor-triterpenoid saponins from Adina rubella

Three new 27-nor-triterpenoid saponias named rubenorside A (1),rubenorside B(2) and rubenorside C (3) were isolated from the roots of Adina rubella.Their structures were characienzed as pyrocincholic acid 3β-O-α-L-rhamnopyranosyl(28→1 )-β-D-glucopyranosyl ester (1),pyrocinchohe acid 3β-O-β-D-glucopyranosyl(1→2)-β-D-fucopyranosyl(28→1)-β-D-glucopyranosyl(1→6)-β-D-glico-pyranosyl ester (2) and pyrocincholic acid 3β-O-β-D-glucopyranosyl(1→2)-β-D-glucopyranosyl(28→1)β-D-glucopyranosyl(1→6)-β-D-glucopyranosyl ester () by spectral methods,especially 2D NMR experiments.