Anticholinesterase Activity Research Articles

Revisiting Purine Nucleoside Cholinesterase Inhibitors - An Experimental Glycon Structure/Activity Relationship Study.

A new family of purine nucleoside cholinesterase inhibitors was disclosed by us, with potency and selectivity over acetylcholinesterase or butyrylcholinesterase controlled by tuning structural and stereochemical features of nucleosides with perbenzylated glycosyl moieties. Design, synthesis, and biological evaluation of new purine nucleosides were used to investigate glycon protecting group pattern required for anticholinesterase activity and selectivity. Regioselective chemistry to introduce methyl/benzyl groups in glycon donors and Nglycosylation was used to acquire the target nucleosides. Evaluation of their biological potential and selectivity as cholinesterase inhibitors was performed. Synthetic strategies chosen resulted in high glycon donor's overall yield and regio- and stereoselectivity was found in N-glycosylation reaction. Some of the new nucleosides are cholinesterase inhibitors and selectivity for butyrylcholinesterase was also achieved. N-glycosylation reaction was stereoselective for the β-anomers while regioselectivity was achieved for the N9 isomers when glycon positions 2 and 3 were methylated. Cholinesterase inhibition was found when the 2,3-di-O-benzyl-4-O-methyl pattern is present in the sugar moiety. Amongst the new compounds, the two most promising ones showed micromolar inhibition (mixed inhibition), being one of them selective for butyrylcholinesterase inhibition.

Donepezil-induced psychosis: a cautionary report of a rare adverse reaction

IntroductionDonepezil is an acetylcholinesterase inhibitor approved by the Food and Drug Administration for the treatment of dementia in Alzheimer’s disease. While it is not curative for Alzheimer’s disease, donepezil has been shown to improve symptoms and slow disease progression; however, cases of rare psychiatric adverse effects, including hallucinations, mania, and increased confusion, have been reported. This report presents a case of donepezil-induced psychosis, which quickly resolved following cessation of the offending medication.ObjectivesTo illustrate a unique case of donepezil-induced psychosisMethodsThe patient is an 81-year-old male with a history of late-onset Alzheimer’s disease, mild depression, hypertension, hyperlipidemia, gastroesophageal reflux disease, and myocardial infarction. The patient was prescribed oral donepezil 10mg twice daily to manage his late-onset Alzheimer’s disease. Subsequently, he began developing persecutory delusions, increased agitation toward his family, and auditory hallucinations. His symptoms were worse at night after taking the donepezil, and he regularly requested to have a firearm for self-defense in the late hours of the night. His symptoms progressed for several weeks before his family brought him into the geriatric psychiatry clinic to address his psychosis. The family recognized that these new symptoms started shortly after the patient began taking donepezil and had already started decreasing the dose to half of what was originally prescribed.ResultsThis patient experienced symptom remission from psychosis immediately upon discontinuation of donepezil. The patient and his family reported significant improvement with no continuation of hallucinations or paranoia. There was also reported improvement in mood and irritability, and the patient appeared significantly better upon follow-up with geriatric psychiatry. Due to this immediate improvement, the suspected causative factor in the precipitation of psychosis in this patient is the anticholinesterase activity of the donepezil. Although the prescribing information of donepezil details inadequate data proving an association between donepezil and psychotic symptoms, two other published case reports (Yorston GA et al. J Psychopharmacol 2000;14:303-4, Pozzi FE et al. Case Rep Neurol 2022; 14:359-365), along with this one, provide evidence of a causal relationship between the two. The patient was switched to memantine therapy and has remained free of psychotic symptoms thus far.ConclusionsThis case demonstrates the caution required among clinicians when prescribing donepezil for the treatment of Alzheimer’s disease. There needs to be a more focused risk evaluation of potential psychiatric adverse effects in patients treated with donepezil.Disclosure of InterestNone Declared

Non-targeted metabolomics and chemometrics for saffron (Crocus sativus L.) authentication and adulteration detection in relation to its anticholinesterase activity

Saffron (Crocus sativus L.), is a spice of vulnerable medical importance. It is often adulterated to lower its quality and efficacy. The present study sought to detect the level of adulteration in five traded saffron collected from different localities using a high-performance liquid chromatography coupled with high resolution tandem mass spectrometry (UPLC-HR-MS/MS) technique. In total, 62 metabolites were identified in the five extracts namely from monoterpene aldehydes, flavonoid derivatives, apocarotenoids and carotenoids classes as well as chemical markers of adulteration. One common adulterant; Gardenia jasminoides Ellis was detected through the simultaneous determination of its specific constituents including geniposide, shanzhiside and major jasminosides. Also, one synthetic dye; auramine-O was detected in one marketed saffron product. The anticholinesterase activity of the five marketed saffron was also evaluated. Furthermore, saffron samples that contain high crocin levels possessed a promising anticholinesterase activity. It was detected for the first time that auramine-O dye is sometimes used as a potential adulterant of saffron. In spite of the grand researches on saffron, it still lacks an accurate evaluation of the commercial saffron products. The results of our study showed that high adulteration rate of trade saffron not only reduces saffron efficacy as a herbal remedy but may also simultaneously represent a health risk.

Biomolecular Screening of Pimpinella anisum L. for Antioxidant and Anticholinesterase Activity in Mice Brain.

Hundreds of the plants have been explored and evaluated for antioxidant and anti-amnesic activities, so far. This study was designed to report the biomolecules of Pimpinella anisum L. for the said activities. The aqueous extract of dried P. anisum seeds was fractionated via column chromatography and the fractions so obtained were assessed for the inhibition of acetylcholinesterase (AChE) via in vitro analysis. The fraction which best inhibited AChE was so named as the P. anisum active fraction (P.aAF). The P.aAF was then chemically analyzed via GCMS, which indicated that oxadiazole compounds were present in it. The P.aAF was then administered to albino mice to conduct the in vivo (behavioral and biochemical) studies. The results of the behavioral studies indicated the significant (p < 0.001) increase in inflexion ratio, by the number of hole-pokings through holes and time spent in a dark area by P.aAF treated mice. Biochemical studies demonstrated that the oxadiazole present in P.aAF on one hand presented a noteworthy reduction in MDA and the AChE level and on the other hand promoted the levels of CAT, SOD and GSH in mice brain. The LD50 for P.aAF was calculated as 95 mg/Kg/p.o. The findings thus supported that the antioxidant and anticholinesterase activities of P. anisum are due to its oxadiazole compounds.

Potential of Tetradenia riparia leaf essential oil and its fractions in controlling Aedes aegypti and Rhipicephalus microplus larvae

Tetradenia riparia (Hochst.) Codd (Lamiaceae) is a shrub, commonly known as ginger bush or false myrrh, and several studies have shown that T. riparia exhibits a variety of biological properties. This study aimed to determine the chemical composition of T. riparia essential oil and its fractions, investigate their anticholinesterase activity, and assess their larvicidal activity against the cattle tick Rhipicephalus microplus and the mosquito Aedes aegypti. Eleven essential oil fractions were obtained by fractionation and analyzed by gas chromatography/mass spectrometry. Larvicidal activity against R. microplus and third-instar A. aegypti was assessed using a larval packet test and a larval immersion test, respectively. Anticholinesterase activity was determined by a bioautographic method. Forty-nine compounds were identified in the essential oil, of which the major classes were oxygenated sesquiterpenes (45.95%) and sesquiterpene hydrocarbons (35.20%) and the major components were isospathulenol (17.40%), β-caryophyllene (15.61%), 14-hydroxy-9-epi-caryophyllene (10.07%), 14-hydroxy-α-muurolene (8.32%), and 9β,13β-epoxy-7-abietene (5.53%). Bioassays showed that T. riparia essential oil (LC50 = 1.56 µg/mL) and FR3 (LC50 = 0.30 µg/mL) were the most active against R. microplus and A. aegypti larvae, respectively. The essential oil and FR1, FR2, and FR3 exhibited acetylcholinesterase inhibitory activity. These results indicate that T. riparia essential oil and its fractions hold promise in the development of novel, environmentally safe agents for the control of R. microplus and A. aegypti larvae.

Phytochemical Analysis, Antioxidant, and Acetylcholinesterase Inhibitory Activity of Propolis from Northeastern Algeria

Propolis is a bee resinous substance consisting mainly of phenolic compounds having nutritional and therapeutic properties and formed by the mixing of the tree and plant secretions collected by honey bees. Herein, the present study was aimed to assess the antioxidant and anticholinesterase activity of ethanolic and acetone propolis extracts from two sampling sites in Souk Ahras city (northeast Algeria). The antioxidant activity of the extracts was determined by using the common antioxidant assays (1,1-diphenyl-2-picrylhydrazyl [DPPH], acide 2-2’-azino-bis (3-ethylbenzothiazoline-6-sulphonique) [ABTS], galvinoxyl radical [GOR], and cupric reducing antioxidant capacity [CUPRAC]), and the anticholinesterase activity was determined against acetylcholinesterase (AChE). Moreover, the total phenolic (TPC), flavonoid (TFC), and condensed tannins (CTC) contents were quantified. The propolis extracts showed a potent antioxidant/inhibitory activity which almost met that of synthetic antioxidants used as standards (butylated hydroxytoluene [BHT] and butylated hydroxyanisole [BHA]). In addition, the AChE activity was highly strongly inhibited in a dose-dependent manner by the propolis extracts. The propolis extracts proved their richness in bioactive molecules able to enhance various biological activities and processes.

Ethnopharmacological review, phytochemistry and bioactivity of the genus Geissospermum (Apocynaceae)

This narrative review aims to update the ethnopharmacology, phytochemistry and biological activities of Geissospermum species described in the literature, in order to contribute to the knowledge of bioactive compounds of therapeutic interest and establish directions for future research with this genus. The term “Geissospermum” was used to perform searches in different databases such as NDLTD (Digital Library Network of Theses and Dissertations), Google Scholar, PubChem, Scifinder, Web of Science, SciELO, PubMed and Science Direct. Google's National Institute of Industrial Property and Patents (INPI) was also consulted. The keywords indole alkaloids, quina-quina, Geissospermum, Geissospermum reticulatum and malaria were used in the search. Publications in Portuguese, French, Spanish and English published between 1950 and 2022 were included. Indole alkaloids are the main secondary metabolites found in this genus, and several molecules have already been isolated, which may be related to the described pharmacological activities. Extracts and isolated compounds showed antitumor, antimalarial, antinociceptive, anti-inflammatory, anticholinesterase, anti-HIV, antimicrobial and antioxidant activity. Plants of the genus Geissospermum are used in Brazil mainly by the Amazonian peoples to treat various pathologies. Biological activities reported for extracts and isolated compounds are consistent with etonopharmacological use against malaria, cancer and other diseases. Future work with Geissospermum species is needed to elucidate the mechanism of action of the isolated alkaloids, as well as their toxicological profile.

Therapeutic potential of blackberry extract in the preventing memory deficits and neurochemical alterations in the cerebral cortex, hippocampus and cerebellum of a rat model with amnesia.

The blackberry (Rubus sp.) is a popular fruit that has a high concentration of phenolic compounds. Pharmacological investigations have demonstrated the important biological activities of the blackberry extract, such as neuroprotective actions. This study aimed to evaluate the effects of blackberry extract on memory and neurochemical parameters in rats subjected to scopolamine (SCO)-induced amnesia. Male rats were divided into five groups: I, control (saline); II, SCO; III, SCO + Rubus sp. (100mg/kg); IV, SCO + Rubus sp. (200mg/kg); and V, SCO + donepezil (5mg/kg). Blackberry extract and donepezil were orally administered for 10days. On day 11, group I received saline, and groups II, III, IV, and V received SCO (1mg/kg) intraperitoneally after object recognition behavioral training. Twenty-four hours after the training session, animals were subjected to an object recognition test. Finally, the animals were euthanized, and the cerebral cortex, hippocampus, and cerebellum were collected to evaluate the oxidative stress and acetylcholinesterase (AChE) activity. Rubus sp. extract prevented memory impairment induced by SCO in a manner similar to that of donepezil. Additionally, Rubus sp. extract and donepezil prevented the increase in AChE activity induced by SCO in all the evaluated brain structures. SCO induced oxidative damage in the cerebral cortex, hippocampus, and cerebellum, which was prevented by Rubus sp. and donepezil. Our results suggest that the antioxidant and anticholinesterase activities of Rubus sp. are associated with memory improvement; hence, it can potentially be used for the treatment of neurodegenerative diseases.

High potential of the genus Allanblackia (Guttiferae): Phytochemistry, pharmacology, and traditional uses over the past half-century

The genus Allanblackia is part of the flowering plants of the Guttiferae family, with all its ten species growing across the rainforest belts of West, Central and East Africa. Allanblackia species have the largest fruits of all plants in the African rainforest. They are evergreen, dioecious, and medium-sized trees with average heights in the range 25–40 m and can produce more than 250 fruits per year. Their stem barks are reddish-brown, with small circular or rectangular scales over small red pits. The trunk is straight, cylindrical, without buttresses but sometimes basally thickened; with numerous branches and longitudinal grooves. Leaves are opposite, simple and entire; while flowers are unisexual, fragrant, and of pink/red or white/cream colour. Fruits are large, ellipsoid berries 10–50 cm × 15 cm in size, with five longitudinal ridges, while seeds are ovoid 3 cm × 2 cm × 1.5 cm. In addition to the numerous uses of Allanblackia in traditional medicine, the consumption and commercial exploitation of its seed oils are of great current interest. However, to date, there is no literature review collating the traditional uses, phytochemistry and biological activities of this genus. Therefore, the present review aims to provide a current, relevant and comprehensive summary of the botany, ethnomedicinal uses, phytochemistry, and biological activities of plants of the genus Allanblackia over the past half-century (1971 to 2021). To this end, a review of all published literature was conducted using various online scientific databases. According to the findings, the Allanblackia species are mostly used in folk medicine for the management of infectious and respiratory diseases. Chemical analysis of the genus Allanblackia revealed that xanthones and biflavonoids represent 51% and 16% of the total secondary metabolites, respectively and could therefore be considered as taxonomic markers of the genus. Extracts and isolates from some species of this genus were reported to exhibit promising antimicrobial, antileishmanial, anticholinesterase and cytotoxic activities, and therefore are vital enough to deserve further attention in new drug discovery.

Design, synthesis, antioxidant and anticholinesterase activities of novel isonicotinic hydrazide-hydrazone derivatives

The design and synthesis of hydrazone derivatives are increasing in popularity day by day due to the significant biological activities of this scaffold. In the present study, twelve novel isonicotinic hydrazide-hydrazone analogues were synthesized by the condensation reaction of isonicotinic hydrazide with benzaldehyde possessing sulfonate moiety. The structures of the novel compounds have been characterized in detail using spectroscopic techniques. All compounds have shown inhibitory effects against the AChE enzyme at rates ranging from 21.00 to 59.48%. Among them, compound 5 has exhibited the best inhibitory effect of 59.48% against AChE at a concentration of 0.1 mM. Furthermore, to determine how effective the novel compounds are as antioxidants, FRAP and DPPH studies were also carried out. FRAP values in compounds 1–12 were found to range from 26.989–3415.556 µmol FeSO4.7H2O/mg. They also displayed moderate antioxidant potential in the range of SC50=0.03–87.32 mg/mL compared with the control Trolox (SC50 =0.004) in DPPH radical scavenging activities. It was seen that the AChE inhibition percentages of the compounds were in the range of 23.04–58.10% at 0.1 mM concentration. This is the first research on the synthesis, antioxidant and enzyme inhibition properties of these compounds.

Para-Substituted Thiosemicarbazones as Cholinesterase Inhibitors: Synthesis, In Vitro Biological Evaluation, and In Silico Study.

The current research reports the synthesis of 14 para-substituted thiosemicarbazone derivatives in good to excellent yields using standard procedures. Initially, 4-ethoxybenzaldehyde (1) and 4-nitrobenzaldehyde (2) were refluxed with thiosemicarbazide in the presence of acetic acid in ethanol for 4-5 h. Then, various substituted phenacyl bromides were treated with the desired thiosemicarbazones (3 and 4) in the presence of triethylamine in ethanol with constant stirring for 5-6 h. The resulting derivatives were confirmed through electron impact mass spectrometry and 1H NMR spectroscopy and evaluated for anticholinesterase inhibitory activity. Among the series, four compounds, 19, 17, 7, and 6, showed potent inhibitory activity against the acetylcholinesterase (AChE) enzyme, having IC50 values of 110.19 ± 2.32, 114.57 ± 0.15, 140.52 ± 0.11, and 160.04 ± 0.02 μM, respectively, compared with standard galantamine (IC50 = 104.5 ± 1.20 μM). Similarly, compounds 19 (IC50 = 145.11 ± 1.03 μM), 9 (IC50 = 147.20 ± 0.09 μM), 17 (IC50 = 150.36 ± 0.18 μM), and 6 (IC50 = 190.21 ± 0.13 μM) were the most excellent inhibitors of butyrylcholinesterase (BChE) when compared with the standard drug galantamine (IC50 = 156.8 ± 1.50 μM). In silico studies were accomplished on the produced derivatives in order to explain the binding interface of compounds with the active sites of AChE and BChE enzymes.

Conjugates of Tacrine and Salicylic Acid Derivatives as New Promising Multitarget Agents for Alzheimer's Disease.

A series of previously synthesized conjugates of tacrine and salicylamide was extended by varying the structure of the salicylamide fragment and using salicylic aldehyde to synthesize salicylimine derivatives. The hybrids exhibited broad-spectrum biological activity. All new conjugates were potent inhibitors of acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) with selectivity toward BChE. The structure of the salicylamide moiety exerted little effect on anticholinesterase activity, but AChE inhibition increased with spacer elongation. The most active conjugates were salicylimine derivatives: IC50 values of the lead compound 10c were 0.0826 µM (AChE) and 0.0156 µM (BChE), with weak inhibition of the off-target carboxylesterase. The hybrids were mixed-type reversible inhibitors of both cholinesterases and displayed dual binding to the catalytic and peripheral anionic sites of AChE in molecular docking, which, along with experimental results on propidium iodide displacement, suggested their potential to block AChE-induced β-amyloid aggregation. All conjugates inhibited Aβ42 self-aggregation in the thioflavin test, and inhibition increased with spacer elongation. Salicylimine 10c and salicylamide 5c with (CH2)8 spacers were the lead compounds for inhibiting Aβ42 self-aggregation, which was corroborated by molecular docking to Aβ42. ABTS•+-scavenging activity was highest for salicylamides 5a-c, intermediate for salicylimines 10a-c, low for F-containing salicylamides 7, and non-existent for methoxybenzoylamides 6 and difluoromethoxybenzoylamides 8. In the FRAP antioxidant (AO) assay, the test compounds displayed little or no activity. Quantum chemical analysis and molecular dynamics (MD) simulations with QM/MM potentials explained the AO structure-activity relationships. All conjugates were effective chelators of Cu2+, Fe2+, and Zn2+, with molar compound/metal (Cu2+) ratios of 2:1 (5b) and ~1:1 (10b). Conjugates exerted comparable or lower cytotoxicity than tacrine on mouse hepatocytes and had favorable predicted intestinal absorption and blood-brain barrier permeability. The overall results indicate that the synthesized conjugates are promising new multifunctional agents for the potential treatment of AD.

An Overview of 1,2,3-triazole-Containing Hybrids and Their Potential Anticholinesterase Activities.

Acetylcholine (ACh) neurotransmitter of the cholinergic system in the brain is involved in learning, memory, stress responses, and cognitive functioning. It is hydrolyzed into choline and acetic acid by two key cholinesterase enzymes, viz., acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE). A loss or degeneration of cholinergic neurons that leads to a reduction in ACh levels is considered a significant contributing factor in the development of neurodegenerative diseases (NDs) such as Alzheimer's disease (AD). Numerous studies have shown that cholinesterase inhibitors can raise the level of ACh and, therefore, enhance people's quality of life, and, at the very least, it can temporarily lessen the symptoms of NDs. 1,2,3-triazole, a five-membered heterocyclic ring, is a privileged moiety, that is, a central scaffold, and is capable of interacting with a variety of receptors and enzymes to exhibit a broad range of important biological activities. Recently, it has been clubbed with other pharmacophoric fragments/molecules in hope of obtaining potent and selective AChE and/or BuChE inhibitors. The present updated review succinctly summarizes the different synthetic strategies used to synthesize the 1,2,3-triazole moiety. It also highlights the anticholinesterase potential of various 1,2,3-triazole di/trihybrids reported in the past seven years (2015-2022), including a rationale for hybridization and with an emphasis on their structural features for the development and optimization of cholinesterase inhibitors to treat NDs.

Chemical composition, antioxidant, anticholinesterase, and alpha-glucosidase activity of Stevia rebaudiana Bertoni extracts cultivated in Algeria

Stevia rebaudiana Bertoni is an endemic species to Paraguay famous for its sweetening power and therapeutic potential for various diseases such as diabetes. The present work evaluates the chemical composition and antioxidant, anticholinesterase, and α-glucosidase activities of S. rebaudiana. The essential oil (EO) of dry Stevia leaves was analyzed by GC/MS and detected the presence of 33 components. Caryophyllene oxide (24.28%), spathulenol (12.31%) and nerolidol (11.8%), and manool oxide (7.36%) were identified as the major ones. The antioxidant activity was evaluated by four complementary methods: DPPH (2,2 diphenylpicrylhydrazyl, ABTS (2, 2’-azino-bis 3-ethylbenzthiazoline-6-sulfonic acid) free radicals scavenging, Cupric reducing antioxidant capacity (CUPRAC), and reducing power. The crude methanolic extract and its fractions showed a variable antioxidant activity and strongly correlated with the content of quantified bioactive compounds. The ethyl acetate fraction showed a very high antioxidant activity close to the tested standards, while EO was active only in the CUPRAC assy. The petrol ether and chloroform fractions showed the best butyrylcholinesterase (BChE) inhibitory activity with IC50 values: 123.7 ± 1.78 and 170.1 ± 0.78 μg/mL, respectively. On the other hand, EO and chloroform revealed a moderate inhibitory activity against acetylcholinesterase (AChE). The in vitro inhibitory effect of the extracts on α-glucosidase indicated that EO effectively inhibited the enzyme with an IC50: 74.9 ± 6.4 µg/mL, better than the standard acarbose. The EO of Stevia has a significant anti-diabetic potential.

Compounds from the Petroleum Ether Extract of Wedelia chinensis with Cytotoxic, Anticholinesterase, Antioxidant, and Antimicrobial Activities.

Wedelia chinensis is a folk medicine used in many Asian countries to treat various ailments. Earlier investigations reported that the petroleum ether extract of the plant has potential biological activity, but the compounds responsible for activity are not yet completely known. Therefore, the current work was designed to isolate and characterize the compounds from the petroleum ether extract and to study their bioactivities. Four compounds including two diterepenes (-) kaur-16α-hydroxy-19-oic acid (1) and (-) kaur-16-en-19-oic acid (2), and two steroids β-sitosterol (3), and cholesta-5,23-dien-3-ol (4) were isolated and characterized. Among the compounds, the diterpenes were found to have more biological activities than the steroidal compounds. Compound 1 showed the highest cytotoxicity with LC50 of 12.42 ± 0.87 μg/mL. Likewise, it possesses good antioxidant activity in terms of reducing power. On the contrary, compound 2 exerted the highest antiacetylcholinesterase and antibutyrylcholinesterase activity. Both the diterpenes showed almost similar antibacterial and antifungal activity. The identification of diterpenoid and steroid compounds with multifunctional activities suggests that W. chinensis may serve as an important source of bioactive compounds which should be further investigated in animal model for therapeutic potential in the treatment of different chronic diseases.

Synthesis, spectroscopic characterization, DFT and molecular dynamics of quinoline-based peptoids

Peptoids mimic the functions of peptides which have a side chain appended to amidic nitrogen instead of α carbon. This structural change in their backbone gives them increased resistance from proteolysis, improved biostability, greater immunogenicity, and better bioavailability. Therefore, they are specifically designed for various biological activities, including antibacterial, antifungal, antioxidant, antifouling, and anticancer properties. The aim of the research is the one-pot synthesis of quinoline-based peptoids 5(a-b)via Ugi-4CR by the reaction of 1R-(-)-myrtenal 1, benzylamine 2, quinoline-based carboxylic acids 3(a-b), and cyclohexyl isocyanide 4. These peptoids were characterized by FT-IR, 1H NMR, 13C NMR, and HR ESI-MS. In computational studies, the spectral results of 5(a-b) were compared with the calculated spectral values computed at B3LYP/6-311G (d,p) level. TD-DFT method was used to predict electron excitation of 5(a-b) and the contribution of orbitals. The electronic transition of peptoids from charge distribution was computed using natural bond order (NBO) analysis. NPA and MEP analysis was calculated to predict charge distribution in 5(a-b). The FMOs analysis was executed to calculate the global reactivity descriptor to predict the reactivity and stability of peptoids. DFT analysis showed that 5b was slightly more reactive than 5a due to extended conjugation. The biological activities were also predicted using an in silico approach that involved molecular docking and molecular dynamic (MD) simulations. The antiulcer, antibacterial, and antifungal activities were predicted based on ligand–protein binding interactions, binding energy calculations, and dissociation constants. 5(a-b) were evaluated in-vitro for anticholinesterase activity, and they showed 71% inhibition. The umbrella sampling was performed to probe ligand–protein binding.

Potential Anti-Cholinesterase Activity of Bioactive Compounds Extracted from Cassia grandis L.f. and Cassia timoriensis DC.

Acetylcholinesterase (AChE) inhibitors remain the primary therapeutic drug that can alleviate Alzheimer's disease's (AD) symptoms. Several Cassia species have been shown to exert significant anti-AChE activity, which can be an alternative remedy for AD. Cassia timoriensis and Cassia grandis are potential plants with anti-AChE activity, but their phytochemical investigation is yet to be further conducted. The aims of this study were to identify the phytoconstituents of C. timoriensis and C. grandis and evaluate their inhibitory activity against AChE and butyrylcholinesterase (BChE). Two compounds were isolated for the first time from C. timoriensis: arachidyl arachidate (1) and luteolin (2). Five compounds were identified from C. grandis: β-sitosterol (3), stigmasterol (4), cinnamic acid (5), 4-hydroxycinnamic acid (6), and hydroxymethylfurfural (7). Compound 2 showed significant inhibition towards AChE (IC50: 20.47 ± 1.10 µM) and BChE (IC50: 46.15 ± 2.20 µM), followed by 5 (IC50: 40.5 ± 1.28 and 373.1 ± 16.4 µM) and 6 (IC50: 43.4 ± 0.61 and 409.17 ± 14.80 µM) against AChE and BChE, respectively. The other compounds exhibited poor to slightly moderate AChE inhibitory activity. Molecular docking revealed that 2 showed good binding affinity towards TcAChE (PDB ID: 1W6R) and HsBChE (PDB ID: 4BDS). It formed a hydrogen bond with TYR121 at the peripheral anionic site (PAS, 2.04 Å), along with hydrophobic interactions with the anionic site and PAS (TRP84 and TYR121, respectively). Additionally, 2 formed three H-bonds with the binding site residues: one bond with catalytic triad, HIS438 at distance 2.05 Å, and the other two H-bonds with GLY115 and GLU197 at distances of 2.74 Å and 2.19 Å, respectively. The evidence of molecular interactions of 2 may justify the relevance of C. timoriensis as a cholinesterase inhibitor, having more promising activity than C. grandis.

Novel ethyl p-methoxy cinnamate rich Kaempferia galanga (L.) essential oil and its pharmacological applications: special emphasis on anticholinesterase, anti-tyrosinase, α-amylase inhibitory, and genotoxic efficiencies.

Kaempferia galanga (L.) is one of the prospective therapeutic plants with an aromatic rhizome, and belongs to the Zingiberaceae family. This herb is commonly used by local practitioners in traditional Asian medicine. In the present investigation, the novel Kaempferia galanga rhizome essential oil rich in ethyl p-methoxy cinnamate (EMCKG) was evaluated using GC/MS for chemical composition analysis. EMCKG was analyzed for its possible antimicrobial, neurodegenerative inhibitory, acetylcholinesterase, anti-inflammatory, and antioxidant activities as well as for the genotoxic effects using the standard methodologies. ANOVA and post hoc was performed to test the statistical significance of the study. GC/MS analysis identified ethyl p-methoxy cinnamate as the major component of EMCKG essential oil with an area percentage of 66.39%. The EMCKG exhibited moderate (DPPH assay IC50 = 15.64 ± 0.263 µg/mL; ABTS assay IC50 = 16.93 ± 0.228 µg/mL) antioxidant activity than standard ascorbic acid (DPPH assay IC50 = 21.24 ± 0.413 µg/mL; ABTS assay IC50 = 21.156 ± 0.345 µg/mL). Similarly, EMCKG showed comparable activity in albumin denaturation (IC50 = 2.93 ± 0.59 µg/mL) and protease inhibitor assay (IC50 = 17.143 ± 0.506 µg/mL) to that of standard sodium diclofenac (IC50 = 23.87 ± 0.729 µg/mL and IC50 = 19.18 ± 0.271 µg/mL, respectively). The EMCKG exhibited a dose-dependent antimicrobial activity pattern with the highest inhibitory activity at 500 µg/mL against Staphylococcus aureus and considerable anticholinesterase activities (IC50 = 21.94 ± 0.109 µg/mL) compared to the standard galanthamine (IC50 = 27.18 ± 0.511 µg/mL). EMCKG also showed strong anti-diabetic activity (IC50 = 18.503 ± 0.480 µg/mL) and anti-tyrosinase activity (IC50 = 14.756 ± 0.325 µg/mL) as compared to the standards used (acarbose IC50 = 20.39 ± 0.231 µg/mL and kojic acid IC50 = 17.73 ± 0.192 µg/mL) in the study. Genotoxicity analysis of EMCKG revealed that at 1 µg/mL concentration has no toxic effects in mitosis of Allium cepa roots (Mitotic Index MI = 13.56% and chromosomal aberration CA = 07.60%). The ANOVA confirmed that except for the anticholinesterase activity, there is insignificant difference for essential oil and standards used for all the other bioactivities thus confirming their interchangeable applicability. Current research provides the basis for the fact that besides being a rich source of ethyl p-methoxycinnamate, EMCKG has the potential for future formulation and development of an inexpensive skin-care agent and for the preparation of anti-diabetic drugs.

DEVELOPMENT AND CHARACTERIZATION OF PLANT OIL-BASED POTENT ANTICHOLINESTERASE MICROEMULSION CONTAINING WITHANIA SOMNIFERA EXTRACT WITH ENHANCED TRANSDERMAL DELIVERY OF PHYTOCONSTITUENTS FOR THE TREATMENT OF COGNITIVE DISORDERS

Objective: This work was carried out to develop Cymbopogan Citratus (lemon grass)oil based microemulsion formulation loaded with the extract of Withania somnifera which possess enhanced transdermal delivery of phytoconstituents with anticholinesterase activity useful in treating Alzheimer’s disease. Methods: Methanolic extract of Withania somnifera roots were prepared and it was investigated for the inhibition of acetylcholinesterase (AChE) activity by Ellman’s assay. Based on the acetylcholinesterase activity, the specific amount of extract was loaded on to the microemulsion formulation. The Cymbopogan Citratus oil, tween 20, ethanol was used as oil phase, surfactant, and cosurfactant, respectively, for the preparation of microemulsion. Pseudo ternary phase diagram was constructed using a water titration method. The microemulsion formulations were characterized for droplet size, PDI, zeta potential and drug content. The optimized formulation was subjected to in vitro drug release and permeation studies and compared with the extract. Results: IC50 value of ashwagandha extract for anticholinesterase activity was found to be 68.73 µg/ml. The optimized microemulsion formulation had droplet size of 199.9±0.3 nm with PDI 0.029±0.2, zeta potential of-19.49±0.7mv and drug content was found to be 97.5±1.3%. The optimized microemulsion formulation showed 85±1.02% release of withaferin A after 24 h of in vitro drug release study. The prepared microemulsion loaded with ashwagandha extract showed excellent permeation of withaferin A(1.4µg/cm2/min) than the flux obtained from extract solution (0.7µg/cm2/min). Conclusion: Optimised microemulsion formulation is suitable for transdermal delivery of anticholinesterase phytoconstituents from ashwagandha extract hence useful in the treatment of Alzheimer’s disease

Antiparasitic Activity of Hippeastrum Species and Synergistic Interaction between Montanine and Benznidazole against Trypanosoma cruzi.

Hippeastrum species have a wide range of biological properties. In Argentina, this genus comprises ten widely distributed species. To evaluate the antiparasitic and anticholinesterase activities and chemical profiles of seven Argentinean Hippeastrum species and determine the synergism between the major isolated alkaloid-montanine-and benznidazole in anti-Trypanosoma cruzi activity. The antiparasitic activity was evaluated through antiproliferative and viability assays against T. cruzi epimastigotes. Synergism assays were performed using the Chou-Talalay method. AChE and BuChE inhibitory activities were also assessed. The alkaloid composition was obtained using GC-MS analysis. All extracts showed strong growth inhibition of T. cruzi epimastigote proliferation. The extracts from H. aglaiae, H. aulicum, and H. hybrid stand out for their potent and total growth inhibition, which was comparable to benznidazole. The H. reticulatum extract showed strong Acetylcholinesterase (AChE) inhibitory activities, while five species showed moderate Butyrylcholinesterase (BuChE) inhibition. Fifteen alkaloids were identified by means of GC-MS. Regarding the synergism assessment, the highest synergistic effect was obtained from the combination of montanine and benznidazole. Hippeastrum species bulb extracts from Argentina were shown to be a good source of antiparasitic alkaloids and cholinesterase inhibitors. The synergism between montanine and benznidazole emerges as a potential combination for future studies to treat Chagas disease.