Three unprecedented thioether-linked dimeric pyrimidines isolated from the medicinal-edible herb Ligusticum striatum DC.

Three unprecedented thioether-linked dimeric pyrimidines, namely ligusticumines A-C, together with twelve known compounds were isolated and identified from the traditional Chinese medicinal-edible herb, Ligusticum striatum DC. The structures of all the isolated compounds were determined from NMR, HRESIMS and X-ray diffraction spectroscopies. Additionally, a novel 3-step synthetic route was developed to synthesize ligusticumine C by substitution, thiolation and coupling, with an overall yield of 5.4%. The inhibitory activities of the isolated compounds against phosphatidylinositol 3-kinase (PI3K) were tested, of which, (3S)-butylphthalide, a characteristic component of L. striatum, showed a potent inhibitory effect on PI3Kα (IC50: 3.6 µg/mL).

A norbisabolane and an arabitol benzoate from Talaromyces marneffei, an endophytic fungus of Epilobium angustifolium.

A norbisabolane and an arabitol benzoate, Talaromarnine A (1), Talaromarnine B (2), together with eight known compounds were obtained from cultures of Talaromyces marneffei, an endophytic fungus of Epilobium angustifolium. Their structures were elucidated by IR, MS, 1D and 2D NMR spectra, and their absolute configuration was determined by single-crystal X-ray diffraction and molecular computation. These compounds were tested for monoamine oxidase, acetylcholinesterase and PI3K inhibitory activity, but no compounds exhibited significant activities.

Two new compounds, Talaromycin A and B, isolated from an endophytic fungus, Talaromyces aurantiacus.

Two new compounds Talaromycin A (1) and Talaromycin B (2) were isolated from a liquid culture of Talaromyces aurantiacus. The structures of 1 and 2 were elucidated by IR, MS, 1D and 2D NMR spectra and comparison of the experimental and calculated electronic circular dichroism spectra. Additional known compounds (3-6) were also isolated. These compounds were tested for monoamine oxidase, acetylcholinesterase and PI3K inhibitory activity, but showed only weak activity.

Colletotrilactam A-D, novel lactams from Colletotrichum gloeosporioides GT-7, a fungal endophyte of Uncaria rhynchophylla.

Four novel lactams, colletotrilactam A-D (1-4), along with six known compounds (5-10) were isolated from the culture broth of Colletotrichum gloeosporioides GT-7, a fungal endophyte of Uncaria rhynchophylla. The structures of these compounds were elucidated by comprehensive NMR spectroscopy. Isolates were tested for monoamine oxidase (MAO) inhibitory activity and compound 9 showed potent MAO inhibitory activity with IC50 value of 8.93±0.34µg/mL, when the IC50 value of iproniazid as a standard was 1.80±0.5µg/mL.

A new furanosteroid from Talaromyces sp. lgt-4, a fungal endophyte isolated from Tripterygium wilfordii.

Wortmannolol (1), a new furanosteroid, along with five known compounds, wortmannolone (2), ergosterol (3), p-hydroxyphenyl ethanol (4), trans-6-dodecene (5), (2Z, 4E) -5-(8-hydroxy-1,5-dimethyl-3-oxo-6-oxabicyclo [3.2.1] octan-8-yl) -3-methylpenta-2,4-dienoic acid (6) were isolated from a fungal endophyte Talaromyces sp. lgt-4. Their structures were elucidated by IR, MS, 1D and 2D NMR spectra. Compound 1 show weak monoamine oxidase inhibitory activity.

Desmodeleganine, a new alkaloid from the leaves of Desmodium elegans as a potential monoamine oxidase inhibitor.

Desmodeleganine (1), a new potential monoamine oxidase inhibitor, along with three known alkaloids, bufotenin (2), hydroxy-N, N-dimethyltryptamine N(12)-oxide (3), 2-(5-methoxy-1H-indol-3-yl)-N, and N-dimethylethylamine (4) were isolated from the leaves of Desmodium elegans. Their structures were elucidated by IR, MS, 1D and 2D NMR spectra. 1 showed strong monoamine oxidase inhibitory activity with IC50 value of 13.92 ± 1.5 µM, when the IC50 value of iproniazid as a standard was 6.5 ± 0.5 µM. The molecular modeling was also performed to explore the binding mode of compounds 1, 2 at the active site of MAO-A and MAO-B.

A rapid thin-layer chromatography bioautographic method for detecting the monoamine oxidase inhibitors in plants.

It is well known that the isolation of monoamine oxidase (MAO) inhibitors from natural sources is an important strategy for drug development in the treatment of depression, Parkinson's disease and Alzheimer's disease. The present work describes developing a thin-layer chromatography (TLC) bioautographic method for detecting MAO inhibitors from plant extracts. The basic principle of the method is that the enzyme oxidises tryptamine into an aldehyde which in turn reacts with 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyltetrazolium bromide to form a blue formazan which makes a blue-coloured background on the TLC plates. Inhibitors of MAO produced white spots on the background. The new TLC bioautographic method has several advantages such as lower consumption of the enzyme, shorter experimental time, more easily observed background of TLC plate and better reproducibility. The detection limits were 10 ng for several known MAO inhibitors.

Isolation, characterization and acetylcholinesterase inhibitory activity of alkaloids from roots of Stemona sessilifolia.

Two new alkaloids, named stenine A (1) and stenine B (2), along with the known compounds neostenine (3), stenine (4) and neotuberostemonine (5), were isolated from the roots of Stemona sessilifolia. Their structures were elucidated by 1D- and 2D-NMR spectra and X-ray single-crystal diffraction experiment. Anti-acetylcholinesterase (AChE) activity of compounds 1-5 were also tested. Compounds 2 and 4 showed significant anti-acetylcholinesterase activities, with IC50 values of 2.1±0.2 µM and 19.8±2.5 µM, resp. The mode of AChE inhibition by Compound 2 (the most potential AChE inhibitor) was reversible and competitive. In addition, molecular modeling was performed to explore the binding mode of compound 2 with AChE.

Steroidal alkaloids from Holarrhena antidysenterica as acetylcholinesterase inhibitors and the investigation for structure-activity relationships.

AIMS: Inhibition of acetylcholinesterase (AChE) is still considered as a strategy for the treatment of neurological disorders such as Alzheimer's disease (AD). Many plant derived alkaloids (such as huperzine A, galanthamine and rivastigmine) are known for their AChE inhibitory activity. The aim of the present work was to isolate and identify new AChE inhibitors from Holarrhen antidysenterica. MAIN METHODS: These compounds were tested for AChE inhibiting activity by the Ellman's method in 96-well microplates. In addition, molecular modeling was performed to explore the binding mode of inhibitors 1-5 at the active site of AChE, and the preliminary structure-activity relationships (SARs) were discussed. KEY FINDINGS: In the course of searching for AChE inhibitors from herb medicines, the total alkaloidal extract from the seeds of H. antidysenterica was found having potent AChE inhibitory activity with an IC(50) value of 6.1 µg/mL. Further bioactivity-guided chromatographic fractionation afforded five steroidal alkaloids, conessine 1, isoconessimine 2, conessimin 3, conarrhimin 4 and conimin 5. All the isolated compounds, except for 2, showed strong AChE inhibiting activity with IC(50) values ranging from 4 to 28 µM. The most active inhibitor is compound 3 with an IC(50) value of 4 µM. The mode of AChE inhibition by 3 was reversible and non-competitive. SIGNIFICANCE: The results suggest that these alkaloids could be potential candidates for further development of new drugs against AD.

Geissoschizine methyl ether, a corynanthean-type indole alkaloid from Uncaria rhynchophylla as a potential acetylcholinesterase inhibitor.

Geissoschizine methyl ether (1), a newly discovered strong acetylcholinesterase (AChE) inhibitor, along with six weakly active alkaloids, vallesiachotamine (2), hisuteine (3), hirsutine (4), isorhynchophylline (5), cisocorynoxeine (6) and corynoxeine (7) have been isolated from Uncaria rhynchophylla. Geissoschizine methyl ether (1) inhibited 50% of AChE activity at concentrations of 3.7 ± 0.3 µg mL(-1) while the IC(50) value of physostigmine as a standard was 0.013 ± 0.002 µg mL(-1). The mode of AChE inhibition by 1 was reversible and non-competitive. In addition, molecular modelling was performed to explore the binding mode of inhibitor 1 at the active site of AChE.

A new alkaloid from Fritillaria ussuriensis Maxim.

Pingbeimunone A (1), a new compound, together with the known ussuriedine (2), benzo[7,8]fluoreno[2,1-b]quinolizine cevane-3,6,16,20-tetrol (3), ebeiedinone (4), pingbeimine C (5) and verticine (6) were isolated from Fritillaria ussuriensis. The structure was elucidated on the basis of spectral analysis (IR, NMR and MS spectroscopy). In addition, their AChE inhibitory activities were also tested.

Improved thin-layer chromatography bioautographic assay for the detection of actylcholinesterase inhibitors in plants.

INTRODUCTION: Thin-layer chromatography (TLC) bioautographic method is a simple and rapid method to screen acetylcholinesterase inhibitors from plant extracts. However, the high consumption of enzyme (6 U/mL) in current methods makes the procedure expensive, which is an obstacle to scientific research centers lacking funding. OBJECTIVE: To develop a new low-cost TLC bioautographic method. METHODOLOGY: A series of compounds, as substrates, were synthesised and their ability to be hydrolysed by acetylcholinesterase was evaluated by the HPLC method. RESULTS: 4-Methoxyphenyl acetate (14) was proved to be an appropriate substrate for TLC bioautographic assay. Therefore a new and cheap TLC bioautographic assay was set up. The mechanism of this new method is that the enzyme converts 4-methoxylphenyl acetate into 4-methoxyphenol, which reacts with a solution of potassium ferricyanide ([K3(FeCN)6]) and iron chloride hexahydrate (FeCl3·6H2O) to make an aquamarine blue coloured background on the TLC plates. Regions of the TLC plate which contain acetylcholinesterase inhibitors show up as light yellow spots against the background. The consumption of enzyme (1 U/mL) in the new method is low and the detection limit of two known acetylcholinesterase inhibitors, huperzine A (0.0001 µg) and physostigmine (0.001 µg), for this assay are close to published values. CONCLUSION: A low-cost TLC bioautographic method was developed, which will benefit research groups pursuing natural acetylcholinesterase inhibitors.

Sesquiterpenoids from the root tubers of Lindera aggregata.

Six new sesquiterpenoids, linderanlide A-F (1-5 and 12), and nine previously reported sesquiterpenoids (6-11 and 13-15) have been isolated from the root tubers of Lindera aggregata. The new structures have been elucidated by extensive spectroscopic interpretation, including UV, IR, NMR, HR-ESI-MS, and CD spectra. The structures of compounds 1, 2, 6, 7, and 9 were further confirmed by single-crystal X-ray diffraction analysis. The absolute configurations of compounds 3-5 were determined by CD spectral analysis.

[Chemical constituents from bark of Caragana opulens].

OBJECTIVE: To investigate the chemical constituents of the bark of Caragana opulens. METHODS: The constituents of the CH3Cl-soluble portion in the 95% ethanol extract were isolated and purified by means of chromatography. The compounds were identified by their physical characteristics and spectral features. RESULTS: Eight compounds were isolated and identified as encelin(1), (+)-13-Hydroxyspathulenol(2), (+) -3alpha,9beta-aromaden dranediol(3), quercetin(4), penduletin(5), lupenol(6), Lup-20(29) -en-3-one (7), beta-sitosterol(8). CONCLUSION: Compounds 1, 2, 5, 7 are isolated for the first time from Caragana genus.

[Chemical constituents in root of Hemerocallis fulva].

OBJECTIVE: To study the chemical constituents of the root of Hemerocallis fulva. METHOD: Compounds were isolated by repeated silica gel, Sephadex LH-20, MCI gel, etc. column chromatography and their structures were determined by spectral analyses and physicochemical properties. RESULT: From the n-butanol fraction of the EtOH extract of the roots of H. fulva, 9 glycosides were isolated and identified as sweroside (1), laganin (2), picraquassioside C (3), puerarin (4), 3'-methoxypuerarin (5), 7-hydro xylnaphthalide-O-beta-D-glucopyranoside (6), orcinol-3-O-beta-glucopyranoside (7), HN saponin F (8), hederagenin-3-0-beta D-glucopyranosyl-(1-3)-alpha-L-arabinopyranoside-28-O-beta-D-glucopyranosyl ester (9). CONCLUSION: Compounds 1-9 were isolated from the genus Hemerocallis for the first time.

[Isolation and structure identification of chemical constituents from Anabasis brevifolia].

AIM: To study the chemical consitituents of the n-butanol-extracts of Anabasis salsa and Various chromatographic techniques were used to the chloroform-extract of Anabasis brevifolia. METHODS: separate and purify the constituents. Their physico-chemical properties and spectral data were used to elucidate their structures. RESULTS: Five compounds were isolated and identified as 2-O-beta-D-glucopyranosyloxy-4,6-dimethoxy phenylenthanone (1), 2-O-(2)-beta-D-glucopyranosyloxy-4, 6-dimethoxy phenylenthanone (2), 3-methyl-but-2-enoic acid-[2-(4-methoxy phenyl)-ethyl]-amide (3), 5,6,7,2'-tetramethoxy isoflavonoid (4), 2'-hydroxy-5,6,7-trimethoxyisoflavonoid (5). CONCLUSION: Compounds 2, 3, and 5 are new compounds. And the others were isolated from Anabasis L. for the first time.

Eudesmane derivatives and other constituents from Saussurea parviflora.

A survey of the whole plant of Saussurea parviflora afforded three compounds 11,12,13-trihydroxy-4(15),8-eudesmadiene-9-one, eudesman-8beta,12-olide-1-O-beta-D-glucoside and 1beta,3beta-dihydroxyursa-9(11),12-diene-3-octadecanoate, as well as 13 known compounds. Their structures were elucidated on the basis of spectral evidence, especially by using NMR spectroscopic techniques. In addition, encelin exhibited effective antitumor activity on L02, SMMC-7721 and HO-8910 cells.