Tannins and Related Compounds from Quisqualis Indica

Continuous exploration of the chemical constituents of Combretaceous plants has led to the discovery of two novel ellagitannins, quisqualin A ( 1 ) and quisqualin B ( 2 ), from the fruits of Quisqualis indica. A total of twenty-one other tannins were also isolated from either the fruits or leaves of Q. indica. including [I] eleven ellagitannins: 2,3-(S)-HHDP-D-glucose ( 3 ), 2,3-(S)-HHDP-4-O-galloyl-D-glucose ( 4 ), 2,3-(S)-HHDP-6-O-galloyl-D-glucose ( 5 ), 2,3-(S)-HHDPA6-di-O-galloyl-D-glucose ( 6 ). pedunculagin ( 7 ), punicalagin ( 8 ), eugeniin ( 9 ), 1-desgalloyleugeniin ( 10 ), casuariin ( 11 ), 5-desgalloylstachyurin ( 12 ), castalagin ( 13 ); [II] five gallotannins-. 6-O-galloyl-D-glucose ( 14 ), 1,6-di-O-galloyl-β-D-glucose ( 15 ), 2,3-di-O-galloyl-D-glucose ( 16 ), 3,4-di-O-galloyl-D-glucose ( 17 ), 4,6-di-O-galloyl-D-glucose ( 18 ); [III] four phenol-carboxylic acids: gallic acid ( 19 ), ellagic acid ( 20 ), flavogallonic acid ( 21 ), brevifolin carboxylic acid ( 22 ) and [IV] one other hydrolyzable tannin: punicalin ( 23 ).     

Cheritamine,A New N-Fatty Acyl Tryptamine and Other Constituents from the Stems of Annona cherimola

A new N-fatty acyl tryptamine, cheritamine ( 30 ), along with thirty-two compounds including nineteen benzenoids, p-hydroxybenzadehyde ( 1 ), p-hydroxybenzoic acid ( 2 ), methylparabene ( 3 ), 3-chlorobenzoic acid ( 4 ), vanillin ( 5 ), isovanillin ( 6 ), vanillic acid ( 7 ), isovanillic acid ( 8 ), methyl vanillate ( 9 ), methyl isovanillate ( 10 ), syringaldehyde ( 11 ), syringic acid ( 12 ), 3,4,5-trimethoxybenzoic acid ( 13 ), trans-methyl p-coumarate ( 14 ), ferulic acid ( 15 ), p-dihydrocoumaric acid ( 16 ), 3-(4-hydroxy-3,5-dimethoxyphenyl)-1,2-propanediol ( 17 ), 3,4,5 -trimethoxyphenyl-β-D-glucopyranoside ( 18 ) and thalictoside ( 19 ); one p-quinone, 2,6-dimethoxy-p-quinone ( 20 ); one purine, uridine ( 21 ); eight alkaloids, nicotinic acid ( 22 ), thalifoline ( 23 ), doryphornine ( 24 ), (–)-norstephalagine ( 25 ), (-)-romucosine ( 26 ), (+)-pronuciferine ( 27 ), (+)-norisocorydine ( 28 ) and oxoasimilobine (29) and three steroids, β-sitosterol-D-glucoside ( 31 ), stigmasterol-D-glucoside ( 32 ) and 6′-(β-sitosteryl-3-O-β-glucopyranosidyl)hexadecanoate ( 33 ), are isolated from the stems of Annona cherimola. These compounds were characterized and identified by physical and spectral evidence.     

Diversity of Chemical Constituents from Saxifraga Montana H.

A thorough phytochemical investigation of the whole plant of Saxifraga montana H. afforded a new glucoside, methyl 6″‐O‐(E)‐p‐hydroxycinnamoxyl‐glucosyringate ( 1 ), and seventeen known natural products, 3‐methyl‐6‐methoxy‐3,4‐dihydroisocoumarin‐8‐O‐β‐D‐glucospyranoside ( 2 ), gallic acid ( 3 ), glucosyringic acid ( 4 ), daphnoretin ( 5 ), chamaejasmoside ( 6 ), myricetin ( 7 ), quercetin ( 8 ), quercetin‐3‐O‐β‐D‐galactopyranoside ( 9 ), quercetin‐3‐O‐α‐L‐arabinoside ( 10 ), quercetin‐3‐O‐β‐D‐glucospyranoside ( 11 ), rutin ( 12 ), quercetin‐3‐O‐β‐D‐glucopyranosyl (6‐1) glucopyranoside ( 13 ), ursolic acid ( 14 ), 5,28‐stigmastadien‐3β‐ol ( 15 ), β‐sitosterol ( 16 ), β‐daucosterin ( 17 ), 6′‐palmitoxyl‐β‐daucosterin ( 18 ). On the basis of various spectroscopic methods, especially intensive 2D‐NMR (COSY, HMQC and HMBC), FAB‐MS and HR‐ESI‐MS techniques, their structures were elucidated.     

Constituents of Flowers of Murraya Paniculata

Three new coumarins, yuehgesin-A (1), -B (2) and -C (3) and 22 compounds—murracarpin (4), mupanidin (5), isomeranzin (6), murralongin (7), scopoletin (10), 7-methoxy-8-(l′-ethoxy-2′-hydroxy-3′-methyl-3′-butenyl)coumarin (11), umbelliferone (12), paniculatin (13), braylin (14), auraptenol (15), meranzin hydrate (16), minumicrolin (17), scopolin (18), caffeine (19), 3,3′,4′,5,5′,6,7-heptamethoxyflavone (20), 4-hy-droxybenzaldebyde (21), p-hydroxybenzoic acid (22), cis- and trans-ferulic acid (23), cis- and transmethyl ferulate (24) and trans-ethylferulate (25)—were isolated and characterized from fresh flowers of Murraya paniculata collected in Taiwan. Their structures were elucidated by spectral methods. The chemotaxonomy of Murraya paniculata is, discussed.     

Contribution à la phytochimie du genre Gentiana. XXV. Etude des composés flavoniques et xanthoniques dans les feuilles de Gentiana X marcailhouana RY. Nouveaux cinnamoyl-C-glucosides flavoniques

Phytochemistry of genus Gentiana XXV: Study of the flavonic and xanthonic compounds in leaves of Gentiana X marcailhouana RY . New cinnamoyl-C-glucosyl-flavones Nine flavonic compounds: isoorientin ( 1 ), isovitexin ( 2 ), isoorientin-4′-O-β-D -glucoside ( 3 ), isovitexin-4′-O-β-D -glucoside ( 4 ), luteolin-7-O-β-D -glucoside ( 5 ), trans-cafeoyl-2′′-isoorientin ( 6 ), trans-feruloyl-2′′-isoorientin ( 7 ), trans-p-coumaroyl-2′′-isoorientin ( 8 ), p-O-β-D -glucosyl-trans-cafeoyl-2′′-isoorientin ( 9 ) and three xanthones: gentioside ( 10 ), isogentisine ( 11 ), mangiferin ( 12 ), have been identified from leaves of Gentiana X marcailhouana RY . Compounds 8 and 9 were described for the first time. The cyclitol L -(+)-bornesitol ( 13 ) has been also isolated.     

Biflavonoids,Lignans, and Related Compounds from the Roots of Diplomorpha canescens

Two new biflavonoids, 14″‐O‐methyldihydrodaphnodorin B ( 1 ) and 14″‐O‐methyldaphnodorin J ( 2 ), along with 16 known compounds, i.e., dihydrodaphnodorin B ( 3 ), daphnodorin J ( 4 ), 3″‐epidihydrodaphnodorin B ( 5 ), daphnodorin B ( 6 ), neochamaejasmin B ( 7 ), sikokianin B ( 8 ), (?)‐syringaresinol ( 9 ), (?)‐syringaresinol 4‐O‐β‐D ‐glucopyranoside ( 10 ), (+)‐nortrachelogenin ( 11 ), (?)‐lariciresinol ( 12 ), (?)‐pinoresinol ( 13 ), syringin ( 14 ), syringinoside ( 15 ), daphnoretin ( 16 ), phorbol 13‐acetate ( 17 ), and methyl paraben ( 18 ) were isolated from the roots of Diplomorpha canescens (Meisn.) C.A. Meyer . The structures were determined on the basis of spectroscopic data.     

The Constituents from the Stems of Annona cherimola

Thirty-five compounds including twenty-one alkaloids, lysicamine ( 1 ), liriodenine ( 2 ), atherospermidine ( 3 ), oxoxylopine ( 4 ), oxoanolobine ( 5 ), oxoglaucine ( 6 ), (-)-anonaine ( 7 ), (-)-asimilobine ( 8 ), (-)-xylopine ( 9 ), (-)-anolobine ( 10 ), (-)-norisocorydine ( 11 ), (+)-laurotetanine ( 12 ), (+)-isocorydine ( 13 ), (-)-N-methylasimilobine ( 14 ), (+)-N-methyllaurotetanine ( 15 ), (-)-norushinsunine ( 16 ), (-)-ushinsunine ( 17 ), (-)-N-formylanonaine ( 18 ), (+)-stepharine ( 19 ), (+)-orentaline ( 20 ), and (-)-kikemanine ( 21 ); four kauranes, ent-kaur-16-en-19-oic acid ( 22 ), 16β-hydroxy-17-acetoxy-ent-kauran-19-al ( 23 ), 17-acetoxy-16β-ent-kauran-19-oic acid ( 24 ), and 16β-hydroxy-17-acetoxy-ent-kauran-19-oic acid ( 25 ); two amides, N-trans-femloyltyramine ( 26 ), and N-trans-caffeoyltyramine ( 27 ); one purine, adenosine ( 28 ); one lactam amide, squamolone ( 29 ); and six steroids, β-sitosterol ( 30 ), stigmasterol ( 31 ), β-sitostenone ( 32 ), stigmasta-4,22-dien-3-one ( 33 ), 6β-hydroxy-β-sitosterone ( 34 ), and 6β-hydroxystigmasterone ( 35 ) are isolated from the stems of Annona cherimola. These compounds were characterized and identified by physical and spectral evidence. Among them, (-)-norisocorydine (11) was elucidated as a new enantiomer with a levorotary configuration, which is isolated for the first time.     

The Constituents of Cananga odorata

Sixteen compounds, (+)-ushinsunine-β-N-oxide ( 1 ), cleistopholine ( 2 ), liriodenine ( 3 ), (-)-anonaine ( 4 ), (+)-nornuciferine ( 5 ), (+)-N-acetylnornuciferine ( 6 ), (-)-ushinsunine ( 7 ), (-)-norushinsunine ( 8 ), (-)-asimilobine ( 9 ), (+)-reticuline ( 10 ), N-trans-feruloyltyramine ( 11 ), β-sitosterol (12) and stigmasterol ( 13 ), lyscamine ( 14 ), (-)-anaxagoreine ( 15 ) and trans-cinnamic acid ( 16 ) were isolated from the methanolic extract of the Cananga odorata. Among them, 1 is a new stereoisomer of ushinsunine-β-N-oxide. The structures of these compounds were established by means of spectral experiments.     

Microbial Transformation of Sesquiterpenes, (−)‐Ambrox® and (+)‐Sclareolide

The microbial transformation of (?)‐Ambrox^® ( 1 ), a perfumery sesquiterpene, by a number of fungi, by means of standard two‐stage‐fermentation technique, afforded ambrox‐1α‐ol ( 2 ), ambrox‐1α,11α‐diol ( 3 ), ambrox‐1α,6α‐diol ( 4 ), ambrox‐1α,6α,11α‐triol ( 5 ), ambrox‐3‐one ( 6 ), ambrox‐3β‐ol ( 7 ), ambrox‐3β,6β‐diol ( 8 ), 13,14,15,16‐tetranorlabdane‐3,8,12‐triol ( 9 ), and sclareolide ( 10 ) (Schemes 1 and 2). Further incubation of compound 10 with Cunninghamella elegans afforded 3‐oxosclareolide ( 11 ), 3β‐hydroxysclareolide ( 12 ), 2α‐hydroxysclareolide ( 13 ), 2α,3β‐dihydroxysclareolide ( 14 ), 1α,3β‐dihydroxysclareolide ( 15 ), and 3β‐hydroxy‐8‐episclareolide ( 16 ) (Scheme 3). Metabolites 2 – 5, 12, 13 , and 16 were found to be new compounds. The major transformations include a reaction path involving hydroxylation, ether‐bond cleavage and inversion of configuration. Metabolites 11 – 16 of sclareolide showed significant phytotoxicity (Table 1). The structures of the metabolites were characterized on the basis of spectroscopic techniques.     

Angular polycyclic thiophenes containing two thiophene rings. I

We describe the synthesis of thieno[2,3-c]dibenzothiophene ( 6 ), thieno[3,2-c]dibenzothiophene ( 10 ), thieno-[3,2-a]dibenzothiophene ( 14 ), thieno[2,3-a]dibenzothiophene ( 16 ), benzo[1,2-b:4,3-b]bisbenzo[b]thiophene ( 18 ), benzo[1,2--6:3,4-b]bisbenzo[b]thiophene ( 20 ), benzo[2,1--6:3,4-b]bisbenzo[b]thiophene ( 22 ), benzo[1,2-b:3,4-g]bisbenzo[b]thiophene ( 27 ), benzo[1,2-b:4,3-e]bisbenzo[b]thiophene ( 29 ), benzo[2,1--6:3,4-g]bisbenzo[b]thiophene ( 36 ), benzo[2,1--6:4,3-e]bisbenzo[b]thiophene ( 38 ), benzo[1,2--6:4,3-g]bisbenzo[b]thiophene ( 41 ), benzo[1,2-b:4,5-g]bisbenzo[b]thiophene ( 42 ), benzo[1,2-b:3,4-e]bisbenzo[b]thiophene ( 44 ) and benzo-[1,2-b:5,4-e]bisbenzo[b]thiophene ( 45 ).     

Benzolignanoid and Polyphenols from Origanum Vulgare

A new dihydrobenzodioxane derivative, origalignanol ( 10 ), together with nine polyphenolic compounds, salvianolic acid A ( 1 ), salvianolic acid C ( 2 ), lithospermic acid ( 3 ), apigenin 7‐O‐β‐D‐glucuronide ( 4 ), apigenin 7‐O‐β‐D‐(6″‐methyl)glucuronide ( 5 ), luteolin, ( 6 ), luteolin 7‐O‐β‐D‐glucopyranoside ( 7 ), luteolin 7‐O‐β‐D‐glucuronide ( 8 ), and luteolin 7‐O‐β‐D‐xylopyranoside ( 9 ), were isolated from the aqueous ethanolic extract of the aerial parts of Origanum vulgare for the first time. The structure of new compound 10 was determined on the basis of spectroscopic methods. Compound 5 is probably an artifact formed during the isolation. Compounds 1, 2 and 3 showed strong DPPH radical scavenging activity with an EC₅₀ of 7.2 ± 0.4, 9.6 ± 0.9, and 9.5 ± 0.7 μM, respectively, and protected rat hepatocytes from CCl₄‐damage at 100 μM.     

Composition of essential oils from four Apiaceae and Asteraceae species growing in Uzbekistan

The chemical composition of essential oils isolated from the aerial parts of Heracleum lehmannianum, Prangos pabularia, Pseudohandelia umbellifera and Pulicaria salviifolia, all of them growing in Uzbekistan, were determined by GC-MS analysis. The main components of the oil from H. lehmannianum were α-phellandrene (10.5%), 1-butanol (9.0%), δ-cadinene (6.2%), α-cadinol (5.7%), τ-muurolol (3.1%), 4-terpineol (2.4%) and α-muurolene (2.6%), while cis-allo-ocimene (17.6%), δ-3-carene (14.2%), limonene (7.6%), 2,4,6-trimethylbenzaldehyde (6.8%), α-terpinolene (6.1%), β-ocimene (4.3%), α-ocimene (4.2%), α-phellandrene (4.2%) were the major oil components in P. pabularia, and borneol (4.4%), t-cadinol (4.1%), α-humulene oxide (4.0%), caryophyllene oxide (3.6%), bornyl chloride (3.1%), β-pinene (2.9%) in P. umbellifera. The essential oil of P. salviifolia had a much more complex composition which was dominated by 4-terpineol (13.4%), α-cadinol (5.7%), 6-epi-shyobunol (5.2%), γ-terpinene (5.0%), δ-cadinene (4.4%), α-terpinene (3.5%).     

Lycopodium Alkaloids from Huperzia serrata

Three new lycopodium alkaloids, huperserramines A–C ( 1 – 3 , resp.), along with 15 known ones, lycopodine‐6α,11α‐diol ( 4 ), lycoposerramine H ( 5 ), lycoposerramine I ( 6 ), lycopodine‐6α‐ol ( 7 ), lycoposerramine M ( 8 ), diphaladine A ( 9 ), lycoposerramine K ( 10 ), lycoposerramine W ( 11 ), huperzine M ( 12 ), luciduline ( 13 ), phlegmariuine N ( 14 ), huperzine A ( 15 ), huperzine B ( 16 ), lycodine ( 17 ), and lycoposerramine R ( 18 ), were isolated from the whole plant of Huperzia serrata. Their structures were established by spectroscopic methods, including 2D‐NMR and MS analyses. All the isolates were evaluated for their inhibitory effects on acetylcholinesterase (AChE) and α‐glucosidase. As a result, lycopodine‐6α,11α‐diol ( 4 ) exhibited more potent α‐glucosidase inhibitory activity (IC₅₀ 148±5.5 μM ) than the positive control acarbose (IC₅₀ 376.3±2.7 μM ).     

Chemical Components of Seriphidium Santolium Poljak

A new biflavonoid glucoside, apigenin‐7‐O‐β‐D‐glucopyranoside‐(3′‐O‐7″)‐quercetin‐3″‐methyl ether ( 1 ) together with twenty known compounds, apigenin ( 2 ), luteolin ( 3 ), chrysoeriol ( 4 ), tricin ( 5 ), hispidulin ( 6 ), pectolinarigenin ( 7 ), eupatilin ( 8 ), 5,7‐dihydroxy‐6,3′,4′,5′‐tetramethoxyflavone ( 9 ), 5,7,4′‐trihydroxy‐6,3′,5′‐trimethoxyflavone ( 10 ), 3,6‐O‐dimethylquercetagetin‐7‐O‐β‐D‐glucoside ( 11 ), 6‐hydroxy‐5,7‐dimethoxy‐coumarin ( 12 ), taraxerol ( 13 ), taraxeryl acetate ( 14 ), a mixture of β‐sitosterol ( 15 ) and stigmasterol ( 16 ), a mixture of the n‐alkyl trans‐p‐coumarates ( 17 ), a mixture of the n‐alkyl trans‐ferulates ( 18 ), 2‐hydroxy‐4,6‐dimethoxyacetophenone ( 19 ), 4‐hydroxy‐2,6‐dimethoxyphenol‐1‐O‐β‐D‐glucopyranoside ( 20 ), and 2‐hydroxycinnamoyl‐β‐D‐glucopyranoside ( 21 ), were isolated from the whole plant of Seriphidium santolium Poljak. The structures of these compounds were determined by means of spectral and chemical studies.     

Systematic analysis of in vitro photo-cytotoxic activity in extracts from terrestrial plants in Peninsula Malaysia for photodynamic therapy

One hundred and fifty-five extracts from 93 terrestrial species of plants in Peninsula Malaysia were screened for in vitro photo-cytotoxic activity by means of a cell viability test using a human leukaemia cell-line HL60. These plants which can be classified into 43 plant families are diverse in their type of vegetation and their natural habitat in the wild, and may therefore harbour equally diverse metabolites with potential pharmaceutical properties. Of these, 29 plants, namely three from each of the Clusiaceae, Leguminosae, Rutaceae and Verbenaceae families, two from the Piperaceae family and the remaining 15 are from Acanthaceae, Apocynaceae, Bignoniaceae, Celastraceae, Chrysobalanaceae, Irvingiaceae, Lauraceae, Lythraceae, Malvaceae, Meliaceae, Moraceae, Myristicaceae, Myrsinaceae, Olacaceae and Sapindaceae. Hibiscus cannabinus (Malvaceae), Ficus deltoidea (Moraceae), Maranthes corymbosa (Chrysobalanaceae), Micromelum sp., Micromelum minutum and Citrus hystrix (Rutaceae), Cryptocarya griffithiana (Lauraceae), Litchi chinensis (Sapindaceae), Scorodocarpus bornensis (Olacaceae), Kokoona reflexa (Celastraceae), Irvingia malayana (Irvingiaceae), Knema curtisii (Myristicaceae), Dysoxylum sericeum (Meliaceae), Garcinia atroviridis, Garcinia mangostana and Calophyllum inophyllum (Clusiaceae), Ervatamia hirta (Apocynaceae), Cassia alata, Entada phaseoloides and Leucaena leucocephala (Leguminosae), Oroxylum indicum (Bignoniaceae), Peronema canescens, Vitex pubescens and Premna odorata (Verbenaceae), Piper mucronatum and Piper sp. (Piperaceae), Ardisia crenata (Myrsinaceae), Lawsonia inermis (Lythraceae), Strobilanthes sp. (Acanthaceae) were able to reduce the in vitro cell viability by more than 50% when exposed to 9.6 J/cm² of a broad spectrum light when tested at a concentration of 20 μg/mL. Six of these active extracts were further fractionated and bio-assayed to yield four photosensitisers, all of which are based on the pheophorbide-a and -b core structures. Our results suggest that the main photosensitisers from terrestrial plants are likely based on the cyclic tetrapyrrole structure and photosensitisers with other structures, if present, are present in minor amounts or are not as active as those with the cyclic tetrapyrrole structure.     

A Hydroxylated Lupeol‐Based Triterpenoid Ester Isolated from the Scurrula parasitica Parasitic on Nerium indicum

(3β,7β)‐7‐Hydroxylup‐20(29)‐en‐3‐yl hexadecanoate ( 1 ), a new lupeol‐based triterpenoid ester, along with sixteen known compounds, 7β,15α‐dihydroxylup‐20(29)‐ene‐3β‐O‐palmitate ( 2 ), lupeol palmitate ( 3 ), lupeol ( 4 ), 3‐oxolup‐20(29)‐ene ( 5 ), ursolic acid ( 6 ), cycloeucalenol ( 7 ), stigmasterol ( 8 ), β‐sitosterol ( 9 ), β‐daucosterol ( 10 ), quercetin ( 11 ), quercetin 3‐O‐α‐L ‐arabinoside ( 12 ), quercetin 3‐O‐α‐L ‐rhamnoside ( 13 ), catechin ( 14 ), gitoxigenin 3‐O‐α‐L ‐rhamnoside ( 15 ), gitoxigenin 3‐O‐α‐D ‐glucoside ( 16 ), and digitoxigenin 3‐O‐α‐L ‐rhamnoside ( 17 ), was isolated from the leaves of the Southern China mistletoe, Scurrula parasitica Linn parasitic on Nerium indicum Mill . Their structures were elucidated by spectroscopic analyses, including 2D‐NMR techniques. Cytotoxic activities of compounds 1 – 7 and 11 – 17 were evaluated against three cancer cell lines, PANC‐1, HL‐60, and SGC‐7901, revealing that compounds 4, 6, 11 , and 15 – 17 exhibited effective cytotoxicities, while others were inactive. A structure? activity relationship study of compounds 1 – 5 indicated that the 3‐OH group in lupeol‐based triterpenoids is essential for antitumor activity.     

Four New Podocarpane‐Type Trinorditerpenes from Aleurites moluccana

Four new podocarpane‐type trinorditerpenenes, (5β,10α)‐12,13‐dihydroxypodocarpa‐8,11,13‐trien‐3‐one ( 1 ), (5β,10α)‐12‐hydroxy‐13‐methoxypodocarpa‐8,11,13‐trien‐3‐one ( 2 ), (5β,10α)‐13‐hydroxy‐12‐methoxypodocarpa‐8,11,13‐trien‐3‐one ( 3 ), and (3α,5β,10α)‐13‐methoxypodocarpa‐8,11,13‐triene‐3,12‐diol ( 4 ), together with four known diterpenes, 12‐hydroxy‐13‐methylpodocarpa‐8,11,13‐trien‐3‐one ( 5 ), spruceanol ( 6 ), ent‐3α‐hydroxypimara‐8(14),15‐dien‐12‐one ( 7 ), and ent‐3β,14α‐hydroxypimara‐7,9(11),15‐triene‐12‐one ( 8 ), were isolated from the twigs and leaves of Aleurites moluccana. Their structures were elucidated by means of comprehensive spectroscopic analyses, including NMR and MS. Except 8 , all compounds were evaluated for their cytotoxicity; compound 4 exhibited moderate inhibitory activity against Raji cells with an IC₅₀ value of 4.24 μg/ml.     

Crotofolane‐ and Casbane‐Type Diterpenes from Croton argyrophyllus

Phytochemical analysis of Croton argyrophyllus led to the isolation of five new diterpenes named (5β,6β)‐5,6 : 13,16‐diepoxycrotofola‐4(9),10(18),13,15‐tetraen‐1‐one ( 1 ), (5β,6β)‐5,6 : 13,16‐diepoxy‐2‐epicrotofola‐4(9),10(18),13,15‐tetraen‐1‐one ( 2 ), (5β,6β)‐5,6 : 13,16‐diepoxy‐16‐hydroxy‐2‐epicrotofola‐4(9),10(18),13,15‐tetraen‐1‐one ( 3 ), (5β,6β)‐5,6 : 13,16‐diepoxy‐16‐hydroxy‐2‐epicrotofola‐4(9), 10(18),13,15‐tetraen‐1‐one ( 4 ) and (2E,5β,6E,12E)‐5‐hydroxycasba‐2,6,12‐trien‐4‐one ( 5 ), in addition to the known diterpenes crotonepetin and depressin, and acetylaleuritolic acid and spinasterol. The structures of the isolated compounds were established by a combination of spectroscopic methods, including HR‐ESI‐MS, 2D‐NMR, and X‐ray crystallography.     

New Acetylcholinesterase‐Inhibitory Pregnane Glycosides of Cynanchum atratum Roots

Three new pregnane glycosides, cynatroside A ( 1 ), cynatroside B ( 2 ), and cynatroside C ( 3 ), isolated from the roots of Cynanchum atratum (Asclepiadaceae), were characterized as 7β‐{[O‐α‐L ‐cymaropyranosyl‐(1→4)‐O‐β‐D ‐digitoxopyranosyl‐(1→4)‐β‐D ‐oleandropyranosyl]oxy}‐3,4,4a,4b,5,6,7,8,10,10a‐decahydro‐6α‐hydroxy‐4b‐ methyl‐2‐(2‐methyl‐3‐furyl)phenanthren‐1(2H)‐one ( 1 ), 7β‐{[O‐β‐D ‐cymaropyranosyl‐(1→4)‐O‐α‐L ‐diginopyranosyl‐(1→4)‐β‐D ‐cymaropyranosyl]oxy}‐3,4,4a,4b,5,6,7,8,10,10a‐decahydro‐2,6α‐dihydroxy‐4b‐methyl‐2‐(2‐methyl‐3‐furyl)phenanthren‐1(2H)‐one ( 2 ), and 7β‐{[O‐α‐L ‐cymaropyranosyl‐(1→4)‐O‐β‐D ‐digitoxopyranosyl‐(1→4)‐β‐L ‐cymaropyranosyl]oxy}‐3,4,4a,4b,5,6,7,8,10,10a‐decahydro‐2,6α‐dihydroxy‐4b‐methyl‐2‐(2‐methyl‐3‐furyl)phenanthren‐1(2H)‐one ( 3 ), respectively. In addition, ten known constituents were identified, i.e., cynascyroside D ( 4 ), glaucoside C ( 5 ), glaucoside D ( 6 ), atratoside A ( 7 ), 2,4‐dihydroxyacetophenone ( 8 ), 4‐hydroxyacetophenone ( 9 ), syringic acid ( 10 ), azelaic acid ( 11 ), suberic acid ( 12 ), and succinic acid ( 13 ). Among these compounds, 1 – 4 significantly inhibit acetylcholinesterase activity.     

Sesquiterpenoids from the Fruits of Alpinia oxyphylla and Their Anti‐Acetylcholinesterase Activity

Fourteen sesquiterpenoids were isolated from the fruits of Alpinia oxyphylla Miq . Their structures were elucidated based on NMR analyses (¹H, ¹³C, DEPT, ¹H,¹H‐COSY, HMQC, HMBC, and NOESY) and identified as 12‐nornootkaton‐6‐en‐11‐one ( 3 ), (+)‐(3S,4aS,5R)‐2,3,4,4a,5,6‐hexahydro‐3‐isopropenyl‐4a,5‐dimethyl‐1,7‐naphthoquinone ( 5 ), nootkatene ( 6 ), 9β‐hydroxynootkatone ( 7 ), 2β‐hydroxy‐δ‐cadinol ( 8 ), 4‐isopropyl‐6‐methyl‐1‐tetralone ( 11 ), oxyphyllone E ( 12 ), oxyphyllone D ( 13 ), oxyphyllanene B ( 15 ), oxyphyllone A ( 16 ), oxyphyllol E ( 17 ), (9E)‐humulene‐2,3;6,7‐diepoxide ( 18 ), mustakone ( 20 ), and pubescone ( 21 ). Among them, 3 was a new norsesquiterpenoid, 8 was a new natural product, and 5, 6, 11, 20, 21 were isolated from A. oxyphylla for the first time. Twenty sesquiterpenoids, 1 – 5 and 7 – 21 , were investigated for their in vitro acetylcholinesterase (AChE) inhibitory activities, including previously isolated seven sesquiterpenoids from A. oxyphylla, (11S)‐12‐chloronootkaton‐11‐ol ( 1 ), (11R)‐12‐chloronootkaton‐11‐ol ( 2 ), nootkatone ( 4 ), oxyphyllenodiol A ( 9 ), oxyphyllenodiol B ( 10 ), 7‐epiteucrenone B ( 14 ), and alpinenone ( 19 ). TLC‐Bioautographic assay indicated that 1 – 4, 7, 14, 16, 18, 19 , and 21 displayed anti‐AChE activities at 10 nmol. Microplate assay confirmed that 19, 18, 16 , and 21 displayed moderate‐to‐weak anti‐AChE activities at the concentration of 100 μM , and 19 was the most potent inhibitor with an IC₅₀ value of 81.6±3.5 μM . The presence of anti‐AChE sesquiterpenoids in A. oxyphylla may partially support the traditional use of this fruit for the treatment of dementia.