Lipoxygenase inhibiting ethyl substituted glycoside from Symplocos racemosa

Phytochemical investigation of Symplocos racemosa resulted in the isolation of a new ethyl substituted glycoside, 1-ethyl brachiose-3'-acetate (1) along with four known compounds ketochaulmoogric acid (2), nonaeicosanol (3), triacontyl palmitate (4) and methyl triacontanoate (5). The substitution of ethyl group on 1 was natural because during the course of extraction and purification ethanol was not used. The structural elucidation of the isolated compounds was based primarily on 1D- and 2D-NMR analysis, including COSY, HMQC, and HMBC correlations. The glycoside 1 and triacontyl palmitate (4) displayed the inhibitory potential against lipoxygenase and urease enzyme, respectively.     

Isolation and characterisation of three new anthraquinone secondary metabolites from Symplocos racemosa

Three new anthraquinone secondary metabolites were isolated from Symplocos racemosa, a small tree of family symplocaceae. The structures of compounds (1–3) were elucidated to be 1,4-dihydroxy-6-(ethoxymethyl)-8-propylanthracene-9,10-dione (1), 1,4-dihydroxy-6-(hydroxymethyl)-8-butylanthracene-9,10-dione (2) and 1,4-dihydroxy-6-(hydroxymethyl)-8-propyl anthracene-9,10-dione (3) using their spectral data, i.e. through IR, UV, ¹H NMR, ¹³C NMR and two-dimensional (2D) NMR techniques including heteronuclear multiple quantum coherence, heteronuclear multiple bond correlation and correlation spectroscopy.     

Berchemins A and B: Novel Enzyme‐Inhibiting Dimeric Lignan Glycosides from Berchemia pakistanica

Phytochemical investigation of Berchemia pakistanica by extensive bioassay‐guided fractionation resulted in the isolation of two novel dimeric lignan glycosides, berchemin A ( 1 ) and berchemin B ( 2 ), and of the four known compounds β‐sitosterol, β‐sitosterol 3‐O‐β‐D ‐glucoside, vavain, and daphnetin 8‐β‐D ‐glucoside. The structures of 1 and 2 were elucidated with the help of modern spectroscopic techniques, and the known compounds were identified by comparing their spectral data with those reported in the literature. Berchemins A and B were found to inhibit lipoxygenase and α‐glucosidase enzymes in a concentration‐dependent fashion.     

New Isoflavone C‐Glycosides from Pueraria lobata

Three new isoflavone C‐glycosides, along with two known isoflavone O‐glycosides, were isolated from the roots of Pueraria lobata (Willd .) Ohwi . The structures of the new compounds were elucidated as 4′,7‐dihydroxy‐3′‐methoxyisoflavone 8‐C‐[β‐d‐ glucopyranosyl‐(1→6)]‐β‐d‐ glucopyranoside ( 1 ), 4′,7‐dihydroxy‐3′‐methoxyisoflavone 8‐C‐[β‐d‐ apiofuranosyl‐(1→6)]‐β‐d‐ glucopyranoside ( 2 ), and 8‐C‐β‐d‐ glucopyranosyl‐4′,7‐dihydroxy‐3′‐methoxyisoflavone 4′‐O‐β‐d‐ glucopyranoside ( 3 ) on the basis of spectroscopic methods, especially 2D‐NMR and MS analyses. The known compounds isolated were identified by comparison of their physical and spectroscopic data with those reported in the literature.     

Site‐Selective O‐Arylation of Glycosides

Direct and site‐selective O‐arylation of carbohydrates has been a challenge in synthesis. Herein we report a method based on copper‐catalyzed O‐arylation to address this challenge. Proper choice of the ancillary ligand on copper is critical for the efficiency and site selectivity of this transformation. This method features mild conditions, tolerates various functional groups, and demonstrates broad substrate scope.     

Dihydrochalcones from Symplocos vacciniifolia

A new dihydrochalcone glucoside, vacciniifolin, along with confusoside, trilobatin and sieboldin were isolated from the leaves of Symplocos vacciniifolia. By the method of spectral analysis, this new compound was elucidated as 2‘,3,4,4‘-tetrahydroxydihydrochalcone 4‘-O-β-D-glu-copyranoside.     

Xanthone O‐Glycosides from the Roots of Pteris Multifida

Two new xanthone glycosides and six known compounds were isolated from the roots of Pteris multifida. Based on spectroscopic and chemical methods, the structures of the new compounds were elucidated as 1‐hydroxy‐4,7‐dimethoxy‐8‐(3‐methyl‐2‐butenyl)‐6‐O‐α‐L‐rhamnopyranosyl‐(1→2)‐[β‐D‐glucopyranosyl‐(1→3)]‐β‐D‐glucopyranosylxanthone ( 1 ), and 1,3‐dihydroxy‐7‐methoxy‐8‐(3‐methyl‐2‐butenyl)‐6‐O‐α‐L‐rhamnopyranosyl‐(1 →2)‐[β‐D‐glucopyranosyl‐(1→3)]‐β‐D‐glucopyranosylxanthone ( 2 ), respectively.     

Megastigmane Glycosides from Docynia indica and Their Anti‐inflammatory Activities

Using various chromatographic methods, three new megastigmane glycosides, docynicasides A – C ( 1  –  3 ) and ten known, (6S,9R)‐vomifoliol 9‐O‐β‐d ‐xylopyranosyl‐(1′′→6′)‐O‐β‐d ‐glucopyranoside ( 4 ), hyperin ( 5 ), quercitrin ( 6 ), quercetin 3‐α‐l ‐arabinofuranoside ( 7 ), naringenin 7‐O‐β‐d ‐glucopyranoside ( 8 ), phloridzin ( 9 ), phloretin 2′‐O‐β‐d ‐xylopyranosyl‐(1→6)‐β‐d ‐glucopyranoside ( 10 ), pinosylvin 3‐O‐β‐d ‐glucopyranoside ( 11 ), tormentic acid ( 12 ), and chlorogenic acid methyl ester ( 13 ) were isolated from the fruits of Docynia indica. Their chemical structures were elucidated by physical and chemical methods. All the isolated compounds were evaluated for the inhibitory activity on NO production in LPS‐stimulated BV2 cells. As the results, compounds 3  –  5 showed significant inhibitory activity on LPS‐stimulated NO production in BV2 cells with the IC₅₀ values ranging from 21.0 to 29.3 μm .     

New Cholinesterase‐Inhibiting Steroidal Alkaloids from Sarcococca saligna

Seven new steroidal alkaloids, 2‐hydroxysalignarine‐E (=(2′E,20S)‐20‐(dimethylamino)‐2β‐hydroxy‐3β‐(tigloylamino)pregn‐4‐ene; 1 ), 5,6‐dihydrosarconidine (=(20S)‐20‐(dimethylamino)‐3β‐(methylamino)‐5α‐pregn‐16‐ene; 2 ), salignamine (=(20S)‐20‐(methylamino)‐3β‐methoxypregna‐5,16‐diene; 3 ), 2‐hydroxysalignamine (=(20S)‐20‐(dimethylamino)‐2β‐hydroxy‐3β‐methoxypregna‐5,16‐diene; 4 ), salignarine‐F (=(2′E, 20S)‐20‐(dimethylamino)‐4β‐hydroxy‐3β‐(tigloylamino)pregn‐5‐ene; 5 ), salonine‐C (=(2′E,20S)‐20‐(dimethylamino)‐3β‐(tigloylamino)pregna‐4,14‐diene; 6 ), and N‐[formyl(methyl)amino]salonine‐B (=(20S)‐20‐[formyl(methyl)amino]‐3β‐methoxypregna‐5,16‐diene; 7 ) have been isolated from the MeOH extract of Sarcococca saligna, along with the six known alkaloids dictyophlebine ( 8 ), epipachysamine‐D ( 9 ), saracosine ( 10 ), iso‐N‐formylchonemorphine ( 11 ), sarcodinine ( 12 ), and alkaloid‐C ( 13 ). The structures of 1 – 7 were deduced from spectral data. Compounds 1 – 13 demonstrated significant activity against acetyl‐ and butyrylcholinesterase.     

Flavone 8‐C‐Glycosides from Haberlea rhodopensis Friv. (Gesneriaceae)

Phytochemical profiling of a MeOH extract from Haberlea rhodopensis by a combination of liquid/liquid extraction, and preparative and semi‐preparative HPLC afforded three new flavone C‐glycosides, hispidulin‐8‐C‐(2″‐O‐syringoyl)‐β‐glucopyranoside ( 3 ), hispidulin 8‐C‐(6‐O‐acetyl‐β‐glucopyranoside) ( 4 ), and hispidulin 8‐C‐(6‐O‐acetyl‐2‐O‐syringoyl‐β‐glucopyranoside) ( 5 ), along with two known phenolic glycosides, myconoside ( 1 ) and paucifloside ( 2 ). The structures were established by extensive spectroscopic analyses including 1D‐ and 2D‐NMR (COSY, HSQC, and HMBC), and HR‐ESI‐TOF‐MS, and by comparison with published data.     

Three New Paeonidanin‐Type Monoterpene Glycosides from Paeonia suffruticosa Andr.

Three new paeonidanin‐type monoterpene glycosides, named suffrupaeonidanins A–C, were isolated as minor components from the root cortex of Paeonia suffruticosa Andr. Their structures were elucidated by a combination of 1D‐ and 2D‐NMR, and mass spectral techniques.     

Three New Cycloartane (=9,19‐Cyclolanostane) Glycosides from Cimicifuga foetida

Three new cycloartane glycosides, 24‐epicimigenol 3‐(α‐L ‐arabinopyranoside) ( 1 ), (3β,16β)‐cycloartane‐3,16,22,24,25‐pentol 3‐(β‐D ‐xylopyranoside) ( 2 ), and (3β,15α,16β)‐cycloartane‐3,15,16,24,25‐pentol 3‐(β‐D ‐xylopyranoside) ( 3 ), together with five known compounds, including four cycloartane glycosides and bergenin, were isolated from the rhizomes of Cimicifuga foetida. Their structures were elucidated by spectroscopic methods.     

Iridoid Glycosides and Phenolic Compounds from the Flowers of Vitex agnus‐castus

A new and rare type of iridoid glycoside, agnusoside ( 1 ), a new caffeoylquinic acid derivative, castusic acid ( 2 ), and a new sugar ester, 1,2‐di‐(4‐hydroxybenzoyl)‐β‐glucopyranose ( 3 ), along with ten known compounds belonging to iridoid glycosides (agnuside, trans‐eurostoside), caffeoylquinic acid derivatives (chlorogenic acid and isochlorogenic acid A), flavonoids (isoorientin, isovitexin, kaempferol 3‐O‐sophoroside, luteolin 6‐C‐(2′′‐O‐trans‐caffeoyl)glucopyranoside, and simple phenolic acids (4‐hydroxybenzoic acid, 3,4‐dihydroxybenzoic acid), chemical classes were isolated from the flowers of Vitex agnus‐castus. The structures of the isolates were established by extensive 1D‐ and 2D‐NMR spectroscopic analysis as well as HR‐ESI‐MS. Agnusoside ( 1 ) represents an unusual type of iridoid glycoside with its 6‐keto C(4) nonsubstituted aglycone.     

Cholinesterase‐Inhibiting New Steroidal Alkaloids from Sarcococca hookeriana of Nepalese Origin

Bioassay‐guided phytochemical investigation of Sarcococca hookeriana has resulted in the isolation and structure elucidation of five new pregnane‐type steroidal alkaloids: (?)‐hookerianamide A (=(2β,3β,4β,20S)‐20‐(dimethylamino)‐3‐[(3‐methylbut‐2‐enoyl)amino]‐5α‐pregn‐16‐ene‐2,4‐diol; 1 ), (+)‐hookerianamide B (=(2α,3β,4β,20S)‐4‐acetoxy‐20‐(dimethylamino)‐3‐[(3‐methylbut‐2‐enoyl)amino]‐5α‐pregnan‐2‐ol; 2 ), (?)‐hookerianamide C (=(2β,3β,20S)‐2‐acetoxy‐20‐(dimethylamino)‐3‐[(3‐methylbut‐2‐enoyl)amino]‐5α‐pregnane; 3 ), (?)‐hookerianamine A (=(3β,20S)‐20‐(dimethylamino)‐3‐(methylamino)‐5α‐pregn‐14‐ene; 4 ), and (+)‐phulchowkiamide A (=(3β,20S)‐20‐(methylamino)‐3‐[(2‐methylbut‐2‐enoyl)amino]‐5α‐pregn‐2‐en‐4‐one; 5 ). These compounds, as well as the two chemically derived acetyl derivatives 6 and 7 , displayed cholinesterase inhibition in a concentration‐dependent manner.     

Discovery of New S‐Glycosides and N‐Glycosides of Pyridine‐biphenyl System with Antiviral Activity and Induction of Apoptosis in MCF7 Cells

Glycosylation of small molecule‐based drugs can dramatically improve the biological activities of the parent scaffold. In the current study, S‐glycosides and N‐glycosides of polyfunctionalized pyridine‐biphenyl system tethered with benzotriazole moiety were designed and synthesized. S‐Glycosides of pyridine‐2‐thione derivatives 5a – h and N‐glycosides of pyridine‐2‐one derivatives 9a , b were synthesized by a facile, convenient, and high‐yielding procedure. The epimers glucose and galactose, acetylated or deacetylated, were used to form the glycone part. The structures of these compounds were confirmed by microanalysis and spectroscopic data (IR, ¹ H–NMR, and ¹³C‐NMR). The anticancer activities of the target compounds, in comparison with standard cisplatin, were assessed by MTT assay against MCF7 cell line. Compounds 4f , 4g , 5f , and 5h exhibited the highest cytotoxic effect on MCF7. The anticancer effect of these four compounds induced the apoptosis as evident by the up‐regulated expression of the apoptotic genes Bax and p53 and down‐regulated expression of the anti‐apoptotic gene BCl₂. S‐Glycoside derivatives are more active than N‐glycosides. Moreover, the nontoxic doses of the tested compounds were evaluated in MA104, FRHK4, BGM, Hep2, and Vero cells. Compounds 4a – d and 5a – d were also evaluated for their antiviral effect against HSV‐1, HAV, and rotavirus Wa strain. The compounds' results showed less, moderated, and high antiviral activities. The docking study for these compounds with MDM2 revealed that deacetylated galactose is important for binding with the receptor as it facilitates the formation of hydrogen bond in the receptor. Rapid overlay of chemical structures analysis was employed to understand the compounds' similarity on the basis of their shape structure using the Tanimoto scores.     

8‐(3,3‐Dimethylallyl)‐Substituted Flavonoid Glycosides from the Aerial Parts of Epimedium koreanum

Ten 8‐(3,3‐dimethylallyl)‐substituted flavonoid glycosides, including the four new flavonol glycosides 1 and 3 – 5 and the new flavanonol glycoside 2 , besides five known flavonol glycosides, were isolated from the aerial parts of Epimedium koreanum Nakai . Their structures were determined by spectroscopic methods, including UV, IR, 1D‐ and 2D‐NMR, ESI‐MSⁿ, HR‐ESI‐MS, and circular dichroism (CD) experiments.     

Five New Xanthenone O‐Glycosides from the Roots of Polygala sibirica L.

Five new xanthenone O‐glycosides, sibiricaxanthone C ( 1 ), sibiricaxanthone D ( 2 ), sibiricaxanthone E ( 3 ), sibiricaxanthone F ( 4 ), and sibiricaxanthone G ( 5 ) were isolated from the roots of Polygala sibirica L., together with the six known xanthenone glycosides 6 – 11 . The structures of new compounds were elucidated on the basis of spectral data and acid hydrolysis.