New steroidal alkaloids from Sarcococca saligna

Two new steroidal alkaloids, salonine-A [(20S)-20-(N,N-dimethylamino)-3beta-(tigloylamino)-5alpha-pregn-14-en-2beta,4beta-diol] (1), and salonine-B [(20S)-20-(N,N-dimethylamino)-3beta-methoxy-pregn-5,16-diene] (2), were isolated from the MeOH extract of Sarcococca saligna, along with a known base, alkaloid-C (3). Their structures were elucidated on the basis of spectroscopic methods. All three compounds were found to be cholinesterase inhibitors.     

Cholinesterase inhibiting and antiplasmodial steroidal alkaloids from Sarcococca hookeriana

Bioguided phytochemical investigation of Sarcococca hookeriana with respect to the cholinesterase enzyme inhibitory assay yielded two new pregnane-type steriodal alkaloids hookerianamide H (1) and hookerianamide I (2), along with three known alkaloids N(a)-methylepipachysamine D (3), sarcovagine C (4) and dictyophlebine (5). Their structures were determined with the aid of extensive spectroscopic analysis. All compounds showed good inhibitory activities against the enzymes acetylcholinesterase (IC(50) 2.9-34.1 microM) and butyrylcholinesterase (IC(50) 0.3-3.6 microM). These compounds also showed moderate antiplasmodial activity (IC(50) 2.4-10.3 microM) against the Plasmodium falciparum chloroquine resistant W2 strain.     

New steroidal alkaloids from Fritillaria imperialis and their cholinesterase inhibiting activities

Two new cevanine steroidal alkaloids, impericine (1) and forticine (2) along with known bases delavine (3), persicanidine A (4), and imperialine (5) were isolated from the bulbs of Fritillaria imperialis. The structures of impericine (1) [(20R,22S,25S)-5alpha-cevanin-23-ene-3beta,6beta,16beta-triol] and forticine (2) [(20S,22S,25S)-5alpha-cevanine-3beta,6beta-diol] were determined with the help of spectroscopic studies. These steroidal bases showed anti-acetylcholinesterase and anti-butyrylcholinesterase inhibitory activity.     

New cholinesterase inhibiting bisbenzylisoquinoline alkaloids from Cocculus pendulus

Phytochemical investigation on Cocculus pendulus (J. R. & G. FORST.) resulted in the isolation of two new and three known bisbenzylisoquinoline alkaloids. The structures of the new alkaloids, kurramine-2'-beta-N-oxide (1) and kurramine-2'-alpha-N-oxide (2), were elucidated with the help of spectroscopic techniques. The cholinesterase inhibitory activities of these bisbenzylisoquinoline alkaloids are reported here for the first time.     

Structure activity relationship studies on antileishmanial steroidal alkaloids from Sarcococca hookeriana

The search for antileishmanial constituents from the medicinal plant Sarcococca hookeriana (Buxaceae) of Nepalese origin has resulted in the isolation of 17 (1-17) active steroidal alkaloids. Compounds 1, 2, and 10 were subjected to derivatization and five chemically derived derivatives (1a, 2a, 10a, 10b, 10c) were also obtained. All these natural compounds and derivatives were found to have potent to mild antileishmanial properties. The IC(50) values were found to be in the range of 0.20-61.44 microg mL(-1) (IC(50) value of standard drug amphotericin B = 0.12 microg mL(-1)). The structure activity relationship indicated that the varieties of functionalities present in ring A of the steroidal alkaloids were found to play a characteristic role to increase the antileishmanial activity.     

Triterpene derivatives from Abies spectabilis leaves of Nepalese origin

Our ongoing studies of Nepalese medicinal plants has led to the isolation and characterization of five new triterpenes, two known triterpenes and two phenolic derivatives from Abies spectabilis (D.Don) Mirb leaves grown in the high mountain. The structures of the isolated compounds were characterized by means of 1D and 2D NMR spectroscopic and MS techniques.     

New steroidal alkaloids from Solanum hypomalacophyllum

Two new steroidal alkaloids (1-2) have been isolated from the leaves and roots of Solanum hypomalacophyllum Bitter, respectively. Their structures have been elucidated as deacetoxysolaphyllidine-3-O-beta-D-glucopyranoside (1) and 4-keto-5,6-dihydro-(20S)-verazine (2). Furthermore, two known steroidal alkaloids, 20R-verazine and 20S-verazine, and the common secondary metabolites oleanolic acid and beta-sitosterol were isolated from the roots, whereas deacetoxysolaphyllidine was obtained from the leaves.     

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.     

Iso-N-formyl-5-en-chonemorphine, a steroidal alkaloid from Sarcococca zeylanica

Chemical investigation of the non-quaternary alkaloidal fraction of the aerial parts of Sarcococca zeylanica of the family Buxaceae furnished a steroidal alkaloid iso-N-formyl-5-en-chonemorphine, which has not been previously reported as a natural product. The structure of this alkaloid was established on the basis of spectroscopic evidence.     

New alkaloids from the leaves of Evodia rutaecarpa

One new indole alkaloid (1) and one new indole alkaloidal glycoside (2), together with nine known alkaloids (3–11), were isolated from the leaves of Evodia rutaecarpa. Their structures were determined on the basis of spectroscopic and chemical methods. Compound 4 exhibited potent activity against Pseudomonas aeruginosa with an MIC value of 7.13 μg/ml.     

Haloxylines A and B, antifungal and cholinesterase inhibiting piperidine alkaloids from Haloxylon salicornicum

Haloxylines A (1) and B (2), new piperidine alkaloids, have been isolated from the chloroform soluble fraction of Haloxylon salicornicum and their structures elucidated by spectroscopic techniques including 2D-NMR. Both the compounds displayed antifungal and cholinesterase enzymes inhibitory potentials.     

New Acetogenins from the Seeds of Annona coriacea

From the hexane and MeOH extracts of Annona coriacea Mart . (Annonaceae) seeds, two novel acetogenins, coriapentocins A and B ( 1 and 2 , resp.) were isolated. The known acetogenin bullacin ( 3 ) was also isolated from the hexane extract. The structures of compounds 1 – 3 were elucidated by NMR and MS analysis, and relative configurations were established by comparison with literature data.     

4-dehydroxyepisarcovagine A,a new steroidal alkaloid from Sarcococca pruniformis Lindl.

A new steroidal alkaloid, 4-dehydroxyepisarcovagine A (1), along with seven known alkaloids, sarcovagine D (2), sarcovagenine C (3), epoxysarcovagenine D (4), Pachysamine L (5), Pachysamine E (6), sarcovagine A (7) and sarcovagine B (8), was isolated from the roots and stems of Sarcococca pruniformis Lindl. The structure of compound 1 was elucidated by means of spectroscopic analysis.     

Four New Steroidal Alkaloids from the Roots of Sarcococca Vagans

SarcococcavagansstaPt(Buxacea),whoserootsareawell-knOWnchnesefolkdrugcalledas"JieGuMu",growsinsouthrmChina(l)fferootSareedintreatInenoftraumahcinjwr.OIilyfewinvestigationsonsteroidalalkloidsofforcavaganshavebeendriedout(2'3).ThisPapermainlythewithstruCturaleluctdationoffourocwseddalaltaloids,edsarcovaginA-D(1,2,3and4).nHffetotal-alkaloidmixnaswereobtainedbothecoarennd95%Et0HexthectsofSrmvngamb}'extractionatbotPHvalues.ffefrachonexndatPH3wasedysubectedt0silicagelcolumnchIomatograph}'.…     

Erythrina alkaloids from leaves of Erythrina arborescens

Continued interest in Erythrina alkaloids resulted in the isolation of 38 alkaloids including 7 undescribed ones from the leaves of Erythrina arborescens Roxburgh. Among the new compounds, erythrivarines H-I were two dimeric alkaloids, while others were Erythrina alkaloid glucosides. Dimeric Erythrina alkaloids and monomers, turcomanidine and isoboldine, showed medium xanthine oxidase inhibition.     

Two new steroidal alkaloids from Veratrum nigrum var. ussuriense

<正>Two new steroidal alkaloids,veraussines A(1) and B(2) were isolated from the roots and rhizomes of Veratrum nigrum var.ussuriense.Their structures were determined as N-(ethoxycarbonyl)- 1α,2β,3α,15α-tetrahydroxy-5β-jervanin- 12-en- 11-one(1) andN-(methoxycarbonyl)- 1α,2β,3α,15α-tetrahydroxy-5β-jervanin- 12-en- 11 -one(2) by spectroscopic analysis.     

Isolation and cholinesterase activity of Amaryllidaceae alkaloids from Nerine bowdenii

Amaryllidaceae species are known as ornamental plants. Some contain galanthamine, an acetylcholinesterase inhibitor. The chemical composition of the alkaloid extract of bulbs of Nerine bowdenii Watson has been analyzed by means of GC/MS. Twenty-two compounds were detected and nineteen of them identified, one of which was belladine. The alkaloid extract showed promising cholinesterase inhibitory activities against human blood acetylcholinesterase (HuAChE; IC50 = 87.9 +/- 3.5 microg/mL) and human plasma butyrylcholinesterase (HuBuChE; IC50 = 14.8 +/- 1.1 microg/mL). Belladine inhibited HuAChE and HuBuChE in a dose-dependent manner with IC50 values of 781 +/- 12.5 microM and 284.8 +/-4.2 microM, respectively.