Variability of Isoquinoline Alkaloid Profiles and Anticholinesterase Activities with Binding-Mode Predictions of Glaucium flavum Population.

In this study, phytochemical and biological activity studies supported by docking were carried out on a species of the genus Glaucium, a repository of isoquinoline alkaloids. The GC-MS (Gas Chromatography-Mass Spectrometry) method is used to characterize the isoquinoline alkaloids of Glaucium flavum Crantz. (Papaveraceae). G. flavum was collected from seven different regions of Türkiye (Antalya, Urla-Izmir, Mordogan-Izmir, Mugla, Assos-Canakkale, Karabiga-Canakkale, Giresun) and totally 17 compounds were detected by GC-MS. Glaucine was found to be the major constituent in the sample collected from Mugla, whereas isocorydine was recorded to be the principal alkaloid in other samples. Further fractionation studies on G. flavum collected from Antalya province in Southwestern Türkiye, yielded five major alkaloids (isocorydine 1, dihydrosanguinarine 2, glaucine 3, dehydroglaucine 4, protopine 5) which were characterized by spectroscopic methods. Anticholinesterase activities of the extracts and isolated alkaloids were also tested by in vitro Ellman method. The isolated compounds were also analyzed by a molecular docking technique to determine the binding orientations in the gorge of the active site of acetylcholinesterase (AChE) and a homology model of butyrylcholinesterase (BuChE). This is the first comparative investigation of the phytochemical composition and biodiversity of Glaucium flavum species growing in Türkiye.

Anti-Alzheimer's disease potential of traditional chinese medicinal herbs as inhibitors of BACE1 and AChE enzymes.

Alzheimer's disease (AD) is a common neurodegenerative disease that often occurs in the elderly population. At present, most drugs for AD on the market are single-target drugs, which have achieved certain success in the treatment of AD. However, the efficacy and safety of single-target drugs have not achieved the expected results because AD is a multifactorial disease. Multi-targeted drugs act on multiple factors of the disease network to improve efficacy and reduce adverse reactions. Therefore, the search for effective dual-target or even multi-target drugs has become a new research trend. Many of results found that the dual-target inhibitors of the beta-site amyloid precursor protein cleaving enzyme 1 (BACE1) and acetylcholinesterase (AChE) found from traditional Chinese medicine have a good inhibitory effect on AD with fewer side effects. This article reviews sixty-six compounds extracted from Chinese medicinal herbs, which have inhibitory activity on BACE1 and AChE. This provides a theoretical basis for the further development of these compounds as dual-target inhibitors for the treatment of AD.

Suillin: A mixed-type acetylcholinesterase inhibitor from Suillus luteus which is used by Saraguros indigenous, southern Ecuador.

Suillus luteus (L.) Roussel is an edible mushroom commonly known as slippery jack or "Kallampa" by indigenous people from Loja province. It is used in traditional medicine to manage gastrointestinal disorders and headaches. In addition, edible mushrooms have been used for neurodegenerative diseases; however, there is no report about the anticholinesterase effect produced by this species. The aim of this work was to isolate the main secondary metabolite of Suillus luteus and characterize its inhibitory potential against acetylcholinesterase. Fruiting bodies were extracted with ethanol (EtOH) and ethyl acetate (EtOAc). From the EtOAc, suillin, is reported as the major compound. The cholinesterase inhibitory potential of extracts and the major isolated compound was assessed by Ellman´s method and progression curves were recorded at 405 nm for 60 min. Donepezil hydroclhoride was used as a positive control. The samples were dissolved in methanol at 10 mg/mL and two more 10× dilutions were included to obtain final concentrations of 1, 0.1 and 0.01 mg/mL at the mix of reaction. IC50, Km, Vmax, and Ki were calculated for suillin. Suillin (200 mg) along with linoleic acid, ergosterol peroxide and ergosterol were isolated. The EtOH and EtOAc extracts exerted a moderate inhibitory effect (IC50 > 200 µg/mL. In adittion, suillin exerted a non-competitive mixed mechanism. against AChE with an IC50 value of 31.50 µM and Ki of 17.25 µM. To the best of our knowledge, this is the first report of the anticholinesterase effect of Suillus luteus and suillin. The kinetic parameters and the moderate potency of the compound determined in this study, encourage us to propose suillin as a promising chemopreventing agent for the treatment of neurodegenerative diseases such as Alzheimer.

Imino-2H-Chromene Based Derivatives as Potential Anti-Alzheimer's Agents: Design, Synthesis, Biological Evaluation and in Silico Study.

A new series of imino-2H-chromene derivatives were rationally designed and synthesized as novel multifunctional agents against Alzheimer's disease. A set of phenylimino-2H-chromenes as well as the newly synthesized iminochromene derivatives were evaluated as BACE1, acetylcholinesterase (AChE), and butyrylcholinesterase (BuChE) inhibitors. The results indicated that among the iminochromene set, 10c bearing fluorobenzyl moiety was the most potent BACE1 inhibitor with an IC50 value 6.31 µM. In vitro anti-cholinergic activities demonstrated that compound 10a bearing benzyl pendant was the best inhibitor of AChE (% inhibition at 30 µM=24.4) and BuChE (IC50 =3.3 µM). Kinetic analysis of compound 10a against BuChE was also performed and showed a mixed-type inhibition pattern. The neuroprotective assessment revealed that compound 11b, a phenylimino-2H-chromene derivative with hydroxyethyl moiety, provided 32.3 % protection at 25 µM against Aß-induced PC12 neuronal cell damage. In addition, docking and simulation studies of the most potent compounds against BACE1 and BuChE confirmed the experimental results.

Fatty acid composition, enzyme inhibitory effect, antioxidant and anticancer activity of extract from Saponaria prostrata WILLD. subsp. anatolica HEDGE.

This study attempts to evaluate the antioxidant, enzyme inhibitory, and anticancer properties as well as fatty acid compositions of endemic Saponaria prostrata WILLD. subsp. anatolica HEDGE. The gas chromatography-mass spectrometry (GC-MS) was used to determine the fatty acid content of methanol: dichloromethane extract from S. prostrata subsp. anatolica (SPA). Enzymatic activity was measured against acetylcholinesterase, butyrylcholinesterase and α-glucosidase. DPPH (2,2-diphenyl-1-picrylhydrazyl) free radical scavenging activity and Ferric reducing antioxidant power assay (FRAP) were conducted to antioxidant properties. The anticancer effect of SPA on human MCF-7 breast cancer and human HCT116 colorectal cancer cell line was evaluated by WST-1 cell viability assay, colony formation assay and wound healing assay. In addition, human VEGF Elisa method was used to determine the anti-angiogenic effect, and the quantitative real-time PCR (qRT-PCR) method on p53, Bax and Bcl-2 mRNA levels were used to evaluate apoptosis. While high amounts of palmitic acid (40.8%), linoleic acid (17.75%) and α-linolenic acid (16.84%) were detected in the SPA, the total amount of unsaturated fatty acid (51.34%) was higher than the total amount of saturated fatty acid (48.66%). SPA displayed the most promising acetylcholinesterase (AChE), butyrylcholinesterase (BuChE) and α-glycosidase (AG) inhibitory activities (AChE: IC50: 18.03 µg/mL, BuChE: IC50: 44.24 µg/mL and AG: IC50: 210.85 µg/mL). The half maximum inhibitory concentration (IC50) of SPA in MCF-7 and HCT116 cells was determined as 259.79 µg/mL and 97.24 µg/mL, respectively. In addition, it was determined that SPA suppresses colony formation and wound closure, and suppresses angiogenesis as well as triggering apoptosis at a significant level. It is true that endemic S. prostrata subsp. anatolica is a potential source of functional food ingredients, but more analytical and in vivo experiments are needed to explore further secondary metabolite diversity and pharmacological properties.

Chemometric-enhanced metabolic profiling of five Pinus species using HPLC-MS/MS spectrometry: Correlation to in vitro anti-aging, anti-Alzheimer and antidiabetic activities.

Detailed metabolic profiling of needles of five Pinus species was investigated using complementary HPLC-MS/MS techniques together with supervised and unsupervised chemometric tools. This resulted in putative identification of 44 compounds belonging to flavonoids, phenolics, lignans, diterpenes and fatty acids. Unsupervised principal component analysis showed that differences were maintained across the metabolites characteristic of each Pinus species, are mainly related to di-O-p-coumaroyltrifolin, p-coumaroyl quinic acid derivative, arachidonic acid, hydroxypalmitic acid, isopimaric acid and its derivative. A supervised Partial Least Squares regression analysis was performed to correlate HPLC-MS/MS profiles with the variation observed in the in vitro anticholinesterase, antiaging and anti-diabetic potential. All investigated Pinus extracts exerted their antiaging activity via increasing telomerase and TERT levels in normal human melanocytes cells compared to the control (untreated cells). Profound inhibition activities of acetylcholinesterase and dipeptidyl peptidase-4 were also observed with P. pinea and P. canariensis extracts having comparable antidiabetic activities to sitagliptin as a standard antidiabetic drug. Our findings suggested that pine needles are a good source of phenolics and diterpenoids that have possible health promoting activities in management and alleviation of diabetic conditions and Alzheimer disease.

Discovery of a Potent Dual Inhibitor of Acetylcholinesterase and Butyrylcholinesterase with Antioxidant Activity that Alleviates Alzheimer-like Pathology in Old APP/PS1 Mice.

The combination of the scaffolds of the cholinesterase inhibitor huprine Y and the antioxidant capsaicin results in compounds with nanomolar potencies toward human acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) that retain or improve the antioxidant properties of capsaicin. Crystal structures of their complexes with AChE and BChE revealed the molecular basis for their high potency. Brain penetration was confirmed by biodistribution studies in C57BL6 mice, with one compound (5i) displaying better brain/plasma ratio than donepezil. Chronic treatment of 10 month-old APP/PS1 mice with 5i (2 mg/kg, i.p., 3 times per week, 4 weeks) rescued learning and memory impairments, as measured by three different behavioral tests, delayed the Alzheimer-like pathology progression, as suggested by a significantly reduced Aß42/Aß40 ratio in the hippocampus, improved basal synaptic efficacy, and significantly reduced hippocampal oxidative stress and neuroinflammation. Compound 5i emerges as an interesting anti-Alzheimer lead with beneficial effects on cognitive symptoms and on some underlying disease mechanisms.

Alkaloids of Abuta panurensis Eichler: In silico and in vitro study of acetylcholinesterase inhibition, cytotoxic and immunomodulatory activities.

Natural products obtained from species of the genus Abuta (Menispermaceae) are known as ethnobotanicals that are attracting increasing attention due to a wide range of their pharmacological properties. In this study, the alkaloids stepharine and 5-N-methylmaytenine were first isolated from branches of Abuta panurensis Eichler, an endemic species from the Amazonian rainforest. Structure of the compounds was elucidated by a combination of 1D and 2D NMR spectroscopic and MS and HRMS spectrometric techniques. Interaction of the above-mentioned alkaloids with acetylcholinesterase enzyme and interleukins IL-6 and IL-8 was investigated in silico by molecular docking. The molecules under investigation were able to bind effectively with the active sites of the AChE enzyme, IL-6, and IL-8 showing affinity towards the proteins. Along with the theoretical study, acetylcholinesterase enzyme inhibition, cytotoxic, and immunomodulatory activity of the compounds were assessed by in vitro assays. The data obtained in silico corroborate the results of AChE enzyme inhibition, the IC50 values of 61.24µM for stepharine and 19.55µM for 5-N-methylmaytenine were found. The compounds showed cytotoxic activity against two tumor cell lines (K562 and U937) with IC50 values ranging from 11.77 µM to 28.48 µM. The in vitro assays revealed that both alkaloids were non-toxic to Vero and human PBMC cells. As for the immunomodulatory activity, both compounds inhibited the production of IL-6 at similar levels. Stepharine inhibited considerably the production of IL-8 in comparison to 5-N-methylmaytenine, which showed a dose dependent action (inhibitory at the IC50 dose, and stimulatory at the twofold IC50 one). Such a behavior may possibly be explained by different binding modes of the alkaloids to the interleukin structural fragments. Occurrence of the polyamine alkaloid 5-N-methylmaytenine was reported for the first time for the Menispermaceae family, as well as the presence of stepharine in A. panurensis.

The oxygenated products of cryptotanshinone by biotransformation with Cunninghamella elegans exerting anti-neuroinflammatory effects by inhibiting TLR 4-mediated MAPK signaling pathway.

Cryptotanshinone (1), a major bioactive constituent in the traditional Chinese medicinal herb Dan-Shen Salvia miltiorrhiza Bunge, has been reported to possess remarkable pharmacological activities. To improve its bioactivities and physicochemical properties, in the present study, cryptotanshinone (1) was biotransformed with the fungus Cunninghamella elegans AS3.2028. Three oxygenated products (2-4) at C-3 of cryptotanshinone (1) were obtained, among them 2 was a new compound. Their structures were elucidated by comprehensive spectroscopic analysis including HRESIMS, NMR and ECD data. All of the biotransformation products (2-4) were found to inhibit significantly lipopolysaccharide-induced nitric oxide production in BV2 microglia cells with the IC50 values of 0.16-1.16 µM, approximately 2-20 folds stronger than the substrate (1). These biotransformation products also displayed remarkably improved inhibitory effects on the production of inflammatory cytokines (IL-1ß, IL-6, TNF-α, COX-2 and iNOS) in BV-2 cells via targeting TLR4 compared to substrate (1). The underlying mechanism of 2 was elucidated by comparative transcriptome analysis, which suggested that it reduced neuroinflammatory mainly through mitogen-activated protein kinase (MAPK) signaling pathway. Western blotting results revealed that 2 downregulated LPS-induced phosphorylation of JNK, ERK, and p38 in MAPK signaling pathway. These findings provide a basal material for the discovery of candidates in treating Alzheimer's disease.

Sensitive and reversible perylene derivative-based fluorescent probe for acetylcholinesterase activity monitoring and its inhibitor.

A reversible fluorescence probe for acetylcholinesterase activity detection was developed based on water soluble perylene derivative, N,N'-di(2-aspartic acid)-perylene-3,4,9,10-tetracarboxylic diimide (PASP). Based on the photo-induced electron transfer (PET), PASP fluorescence in aqueous is quenched after combining with copper ions (Cu2+). Acetylcholinesterase (AChE) is well known to catalyze the hydrolysis of acetylcholine (ATCh) to produce thiocholine, whose affinity is strong enough to capture Cu2+ by thiol (-SH) group from the complex PASP-Cu, resulting in the fluorescence signal of PASP recovers up to 90%. This optical switch is highly sensitive depended on the coordination and dissociation between PASP and Cu2+. We proposed its application for AChE activity detection, as well as its inhibitor screening. According to the change of fluorescence intensity, quantifying the detection limit of AChE was 1.78 mU·mL-1. Classical inhibitors, tacrine and organophosphate pesticide diazinon, were further evaluated for drug screening. The IC50 value of tacrine was calculated to be 0.43 µM, and the detection limit of diazinon was 0.22 µM. Both of these performances were much better than previous results, revealing our probe is sensitive and reversible for screening applications.

Discovery and Biological Evaluation of a Novel Highly Potent Selective Butyrylcholinsterase Inhibitor.

To discover novel BChE inhibitors, a hierarchical virtual screening protocol followed by biochemical evaluation was applied. The most potent compound 8012-9656 (eqBChE IC50 = 0.18 ± 0.03 µM, hBChE IC50 = 0.32 ± 0.07 µM) was purchased and synthesized. It inhibited BChE in a noncompetitive manner and could occupy the binding pocket forming diverse interactions with the target. 8012-9656 was proven to be safe in vivo and in vitro and showed comparable performance in ameliorating the scopolamine-induced cognition impairment to tacrine. Additionally, treatment with 8012-9656 could almost entirely recover the Aß1-42 (icv)-impaired cognitive function to the normal level and showed better behavioral performance than donepezil. The evaluation of the Aß1-42 total amount confirmed its anti-amyloidogenic profile. Moreover, 8012-9656 possessed blood-brain barrier (BBB) penetrating ability, a long T1/2, and low intrinsic clearance. Hence, the novel potential BChE inhibitor 8012-9656 can be considered as a promising lead compound for further investigation of anti-AD agents.

Selective in vitro and in silico enzymes inhibitory activities of phenolic acids and flavonoids of food plants: Relations with oxidative stress.

In this study, the inhibitory potentials of food originated 34 phenolic acids, and flavonoid compounds were screened against acetylcholinesterase, butyrylcholinesterase, urease, and tyrosinase enzymes. All compounds included in this study exhibited high antioxidant activity with an ignorable cytotoxic activity. In general, they also showed poor anti-urease and anti-tyrosinase activities. Compounds in aglycone form (quercetin, myricetin, chrysin, and luteolin) showed strong anticholinesterase activities. No relation was observed between the tested bioactivities except from the case that aglycone compounds exhibited a strong positive relationship between antioxidant activities and anticholinesterase activity. Interestingly, there was a relation between the molecular weights of aglycone compounds and their anticholinesterase activities. The study showed that flavonoids with molecular mass of 250-320 g/mol have high potential of anticholinesterase activities and are valuable for future experiments on animals and humans. Potential inhibitory effects of these molecules on target proteins were investigated using docking and molecular dynamics calculations.

A new fluorescent probe for sensing of biothiols and screening of acetylcholinesterase inhibitors.

A new N2O-type BODIPY probe (LF-Bop) has been proposed for the selective and sensitive detection of biologically relevant small molecular thiols. This detection is based on the Michael addition reaction between the thiol and nitrostyrene groups in the probe, which decreases the quenching effect from the nitro group, thus resulting in the recovery of the deep-red fluorescence from the BODIPY structure. The results show that LF-Bop is able to detect all tested free thiols through a fluorescence turn-on assay. The lowest limit of detection (LOD) for glutathione was found to be down to nanomolar levels (220 nM). Based on this probe, we have developed a new fluorescence assay for the screening of acetylcholinesterase inhibitors. In total, 11 natural and synthetic alkaloids have been evaluated. Both experimental measurements and theoretical molecular docking results reveal that both natural berberine and its synthetic derivative dihydroberberine are potential inhibitors of acetylcholinesterase.

Identification of a Huperzine A-producing endophytic fungus from Phlegmariurus taxifolius.

Highly prized huperzine A (Hup A), a natural alkaloid formerly isolated from the Chinese medicinal plant Huperzia serrata, has been widely used for the treatment of Alzheimer disease, inspiring us to search for endophytic fungi that produce this compound. In this study, we obtained the C17 fungus isolate from the Mexican club moss Phlegmariurus taxifolius, which produced a yield of 3.2 µg/g Hup A in mycelial dry weight, when cultured in potato dextrose broth medium. The C17 isolate was identified as belonging to the genus Fusarium with reference to the colony´s morphological characteristics and the presence of macroconidia and microconidia structures; and this was confirmed by DNA-barcoding analysis, by amplifying and sequencing the ribosomal internal transcribed spacer (rITS).

Inducing secondary metabolite production from Daldinia eschscholzii JC-15 by red ginseng medium.

Red ginseng (RG) is one of the most popular herbal medicines and used as a dietary supplement in recent years. The bioactive ingredient in RG can induce the production of novel microbial metabolite from fermented RG. Using the one strain-many compounds strategy, the reinvestigation of the metabolites from Daldinia eschscholzii JC-15 cultured in red ginseng medium led to the isolation of an unprecedented benzopyran-naphthalene hybrid, daldinsin (1) and a new lactone (2). In this research, a new lactone, 8-hydroxylhelicascolide A (2) instead of helicascolide A was produced by the D. eschscholzii JC-15 induced by the red ginseng medium. Compound 1 showed anti-acetylcholinesterase activity with the inhibition ratio of 38.8% at 50 µM. Compound 2 indicated antimicrobial activities against Fusarium Solani, F. oxysporum, and Escherichia coli with MICs at 128 µg/mL. RG is therefore a promising activator in production of novel microbial metabolite.

Terpenes and Phenylpropanoids as Acetyl- and Butyrylcholinesterase Inhibitors: A Comparative Study.

BACKGROUND: Cholinesterase inhibitors are routinely applied in the treatment of Alzheimer's disease, and seeking new cholinesterase inhibitors is a priority. OBJECTIVES: Twenty seven compounds were compared, including ones not previously tested. An attempt was undertaken to precisely describe the role of alcohol in the inhibitory activity. This paper underlines the role of a "false positive" blank sample in the routine analysis. METHODS: The inhibition of cholinesterase was measured using Ellman's colorimetric method with a few modifications designed by the authors (including the "false-positive" effect). The inhibitory role of ethanol and methanol was also carefully evaluated. The present and past results were compared taking the source of enzyme and alcohol content into consideration. RESULTS: For the first time, new inhibitors were identified, namely: methyl jasmonate, 1R-(-)-nopol ((anti-acetyl-(AChE) and butyrylcholinesterase (BChE) activity)) and 1,4-cineole, allo-aromadendrene, nerolidol, ß-ionone, and (R)-(+)-pulegone (anti-BChE activity). Oleanolic acid and (+)-ß-citronellene (not previously studied) proved to be inefficient inhibitors. For a number of well-known inhibitors (such as nerol, (-)-menthol, (+)-menthol, isoborneol, (-)-bornyl acetate, limonene, α-pinene, ß-pinene, α- ionone, and eugenol) some serious discrepancies were observed between our findings and the results of previous studies. Ethanol and methanol showed no anti-AChE activity up to 0.29% (v/v) and 0.23% (v/v), respectively. Similarly, ethanol up to 0.33% (v/v) and methanol up to 0.29% (v/v) did not inhibit the activity of BChE. CONCLUSION: It can be stated that the impact of alcohol should be precisely determined and that blank "false-positive" samples should be processed together with test samples. Furthermore, the effect of the enzyme origin on the result of this test must be taken into consideration.

[Isolation and identification of endophytic fungi from Huperzia serrata and their metabolites' inhibitory activities against acetylcholinesterase and anti-inflammatory activities].

A total of 27 endophytic fungal strains were isolated from Huperzia serrata,which were richly distributed in the stems and leaves while less distributed in roots. The 27 strains were identified by Internal Transcribed Spacer( ITS) r DNA molecular method and one of the strains belongs to Basidiomycota phylum,and other 26 stains belong to 26 species,9 general,6 families,5 orders,3 classes of Ascomycota Phylum. The dominant strains were Colletotrichum genus,belonging to Glomerellaceae family,Glomerellales order,Sordariomycetes class,Ascomycota Phylum,with the percentage of 48. 15%. The inhibitory activities of the crude extracts of 27 endophytic fungal strains against acetylcholinesterase( ACh E) and nitric oxide( NO) production were evaluated by Ellman's method and Griess method,respectively. Crude extracts of four fungi exhibited inhibitory activities against ACh E with an IC50 value of 42. 5-62. 4 mg·L~(-1),and some fungi's crude extracts were found to inhibit nitric oxide( NO) production in lipopolysaccharide( LPS)-activated RAW264. 7 macrophage cells with an IC50 value of 2. 2-51. 3 mg·L~(-1),which indicated that these fungi had potential anti-inflammatory activities.The chemical composition of the Et OAc extract of endophytic fungus HS21 was also analyzed by LCMS-IT-TOF. Seventeen compounds including six polyketides,four diphenyl ether derivatives and seven meroterpenoids were putatively identified.

Subchronic use of rivastigmine increases procognitive flexibility across multimodal behavioral tasks in healthy male rats.

Rivastigmine (RVT) is a reversible inhibitor of cholinesterase approved worldwide for the treatment of cognitive dysfunctions, especially in Alzheimer's disease. Most previous pre-clinical studies have examined the effects of RVT treatment in a wide variety of pathological research models. Nonetheless, the effects of this drug on sensorimotor gating, memory, and learning tasks in healthy subjects remains unclear. In this study, we investigate the procognitive effects of RVT treatment in healthy rats through sensorimotor gating evaluations (measured as prepulse inhibition of the acoustic startle reflex), active avoidance learning, and spatial memory learning in a radial maze. There is an increase in the amplitude of the startle reflex in RVT-treated rats compared to the control groups, whereas the latency remained constant. Sensorimotor gating values were also incremented compared to those values from controls. In active avoidance, rats treated with RVT learned faster to successfully perform the task compared to controls, but afterwards all groups exhibited virtually identical results. During the sessions in the radial maze, RVT-treated rats committed fewer errors in both the working and reference memory compared to controls. All in all, our results support the hypothesis that RVT treatment may entail procognitive effects in healthy subjects.

Metabolite Profiling by Hyphenated Liquid Chromatographic Mass Spectrometric Technique (HPLC-DAD-ESI-Q-TOF-MS/MS) and Neurobiological Potential of Haplophyllum sahinii and H. vulcanicum Extracts.

In the current study, the ethanol extracts of flower, stem, and root parts of two endemic Turkish species, e. g., Haplophyllum sahinii O. Tugay & D. Ulukus and H. vulcanicum Boiss. & Heldr., were screened against acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) associated with Alzheimer's disease as well as tyrosinase (TYR) linked to Parkinson's disease using ELISA microplate assay at 200 µg/mL. Among the extracts, the highest inhibition was caused by the stem extract of H. sahinii against BChE (IC50 =64.93±1.38 µg/mL). Consistently, all of the extracts were found to exert a selective inhibition towards BChE to some extent. It was only the root extract of H. vulcanicum that could inhibit AChE at low level (IC50 =203.18±5.33 µg/mL). None of the extracts displayed an inhibition over 50 % against TYR. Metabolite profiling of the extracts was achieved by a highly hyphenated liquid chromatographic mass spectrometric technique (HPLC-DAD-ESI-Q-TOF-MS/MS), which revealed the presence of furoquinoline (ß-fagarine, γ-fagarine) and amide (tubasenicine, tubacetine) alkaloids; furano- (rutamarin), pyrano- (xanthyletine), and geranyloxy coumarins; phenylpropanoid (secoisolariciresinol), arylnaphthalene (mono-O-acetyldiphyllin apioside), and dibenzylbutyrolactone (kusunokinin, haplomyrfolin) lignans. Several important differences were observed between the extracts analyzed. ß-Fagarine was the major alkaloid in H. vulcanicum, whereas γ-fagarine was present only in the roots of both Haplophyllum species; moreover, secoisolariciresinol and secoisolariciresinol dimethyl ether were the main lignans in the stems and flowers. This is the first study identifying ChE and TYR inhibitory effect and metabolic profiles of H. vulcanicum and H. sahinii.

Bioactivity-guided identification of flavonoids with cholinesterase and ß-amyloid peptide aggregation inhibitory effects from the seeds of Millettia pachycarpa.

Millettia pachycarpa Benth, a widely used anthelminthic drug in folk, is rich in flavonoids with various bioactivities. This study aimed to identify active flavonoids with anti-Alzheimer's disease (AD) effect from its seeds by a bioassay-guided isolation. A novel rotenoid with unusual oxidative ring-opening skeleton (10) and nine known flavonoids (1-9) were obtained, and their structures were elucidated by NMR and HR-ESIMS analysis. Among all isolates, 7 and 8 showed selective butyrylcholinesterase (BChE) inhibitory activities (IC50 = 2.34 and 11.49 µM, respectively), while 3 was classified as a dual-action inhibitor against acetylcholinesterase (AChE) and BChE (IC50 AChE = 17.14 µM, IC50 BChE = 5.68 µM). Further kinetic study revealed that 3, 7, and 8 were mixed-type BChE inhibitors, but 3 was a competitive AChE inhibitor. Their strong binding affinities to BChE were confirmed by fluorescence quenching analysis. Additionally, 3 and 8 exhibited potent inhibitory effects against ß-amyloid peptide aggregation. These results revealed M. pachycarpa could be a valuable source for anti-AD leads development, and compounds 3, 7 and 8 were worthy of further study as multifunctional or specific agents for AD treatment.