In vitro and in silico cholinesterase inhibitory and antioxidant effects of essential oils and extracts of two new Salvia fruticosa mill. cultivars (Turgut and Uysal) and GC-MS analysis of the essential oils.

The EtOH extracts of the leaves of two new cultivars (Uysal-SFU and Turgut-SFT) of Salvia fruticosa Mill. was tested against acetylcholinesterase (IC50: 30.62 ± 3.27 and 32.97 ± 2.33 µg/mL for SFU and SFT, respectively) and butyrylcholinesterase (IC50: 69.91 ± 1.08 µg/mL and 86.55 ± 1.26 µg/mL), respectively, relevant to Alzheimer's disease. The essential oils showed a stumpy inhibition against AChE and no inhibition against BChE. DPPH radical scavenging activity of the extracts (86.70 ± 0.17% and 86.14 ± 1.13% for SFU and SFT, respectively) was stronger than that of quercetin (85.51 ± 0.17%): Their (1.24 ± 0.05 and 1.04 ± 0.16 for SFU and SFT, respectively) ferric-reducing antioxidant power were close to that of the reference (e.g. quercetin, 1.42 ± 0.14). Molecular docking simulations were performed on their major monoterpenes. Our findings revealed that the leaf EtOH extracts of two cultivars are promising inhibitors of both AChE and BChE.

Cholinesterase Inhibitory and In Silico Toxicity Assessment of Thirty-Four Isoquinoline Alkaloids - Berberine as the Lead Compound.

BACKGROUND: Cholinesterase (ChE) inhibitors used currently in clinics for the treatment of Alzheimer's disease (AD) are the most prescribed drug class with nitrogen-containing chemical formula. Galanthamine, the latest generation anti-ChE drug, contains an isoquinoline structure. OBJECTIVE: The aim of the current study was to investigate the inhibitory potential of thirty-four isoquinoline alkaloids, e.g. (-)-adlumidine, ß-allocryptopine, berberine, (+)-bicuculline, (-)-bicuculline, (+)-bulbocapnine, (-)-canadine, (±)-chelidimerine, corydaldine, (±)-corydalidzine, (-)-corydalmine, (+)-cularicine, dehydrocavidine, (+)-fumariline, (-)-fumarophycine, (+)-α-hydrastine, (+)-isoboldine, 13-methylcolumbamine, (-)-norjuziphine, norsanguinarine, (-)-ophiocarpine, (-)-ophiocarpine-N-oxide, oxocularine, oxosarcocapnine, palmatine, (+)-parfumine, protopine, (+)-reticuline, sanguinarine, (+)-scoulerine, (±)-sibiricine, (±)-sibiricine acetate, (-)-sinactine, and (-)-stylopine isolated from several Fumaria (fumitory) and Corydalis species towards acetyl- (AChE) and butyrylcholinesterase (BChE) by microtiter plate assays. The alkaloids with strong ChE inhibition were proceeded to molecular docking simulations as well as in silico toxicity screening for their mutagenic capacity through VEGA QSAR (AMES test) consensus model and VEGA platform as statistical approaches. The inputs were evaluated in a simplified molecular input-line entry system (SMILES). RESULTS: ChE inhibition assays indicated that the highest AChE inhibition was caused by berberine (IC50: 0.72 ± 0.04 µg/mL), palmatine (IC50: 6.29 ± 0.61 µg/mL), ß-allocryptopine (IC50: 10.62 ± 0.45 µg/mL), (-)-sinactine (IC50: 11.94 ± 0.44 µg/mL), and dehydrocavidine (IC50: 15.01 ± 1.87 µg/mL) as compared to that of galanthamine (IC50: 0.74 ± 0.01 µg/mL), the reference drug with isoquinoline skeleton. Less number of the tested alkaloids exhibited notable BChE inhibition. Among them, berberine (IC50: 7.67 ± 0.36 µg/mL) and (-)-corydalmine (IC50: 7.78 ± 0.38 µg/mL) displayed a stronger inhibition than that of galanthamine (IC50: 12.02 ± 0.25 µg/mL). The mutagenic activity was shown for ß-allocryptopine, (+)- and (-)-bicuculline, (±)-corydalidzine, (-)-corydalmine, (+)-cularicine, (-)-fumarophycine, (-)-norjuziphine, (-)-ophiocarpine-N-oxide, (+)-scoulerine, (-)-sinactine, and (-)-stylopine by means of in silico experiments. The results obtained by molecular docking simulations of berberine, palmatine, and (-)-corydalmine suggested that the estimated free ligand-binding energies of these compounds inside the binding domains of their targets are reasonable to make them capable of establishing strong polar and nonpolar bonds with the atoms of the active site amino acids. CONCLUSION: Our findings revealed that berberine, palmatin, and (-)-corydalmine stand out as the most promising isoquinoline alkaloids in terms of ChE inhibition. Among them, berberine has displayed a robust dual inhibition against both ChEs and could be evaluated further as a lead compound for AD.

Outlining In Vitro and In Silico Cholinesterase Inhibitory Activity of Twenty-Four Natural Products of Various Chemical Classes: Smilagenin, Kokusaginine, and Methyl Rosmarinate as Emboldening Inhibitors.

Cholinesterase (ChE) inhibition is an important treatment strategy for Alzheimer's disease (AD) as acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) are involved in the pathology of AD. In the current work, ChE inhibitory potential of twenty-four natural products from different chemical classes (i.e., diosgenin, hecogenin, rockogenin, smilagenin, tigogenin, astrasieversianins II and X, astragalosides I, IV, and VI, cyclocanthosides E and G, macrophyllosaponins A-D, kokusaginin, lamiide, forsythoside B, verbascoside, alyssonoside, ipolamide, methyl rosmarinate, and luteolin-7-O-glucuronide) was examined using ELISA microtiter assay. Among them, only smilagenin and kokusaginine displayed inhibitory action against AChE (IC50 = 43.29 ± 1.38 and 70.24 ± 2.87 µg/mL, respectively). BChE was inhibited by only methyl rosmarinate and kokusaginine (IC50 = 41.46 ± 2.83 and 61.40 ± 3.67 µg/mL, respectively). IC50 values for galantamine as the reference drug were 1.33 ± 0.11 µg/mL for AChE and 52.31 ± 3.04 µg/mL for BChE. Molecular docking experiments showed that the orientation of smilagenin and kokusaginine was mainly driven by the interactions with the peripheral anionic site (PAS) comprising residues of hAChE, while kokusaginine and methyl rosmarinate were able to access deeper into the active gorge in hBChE. Our data indicate that similagenin, kokusaginine, and methyl rosmarinate could be hit compounds for designing novel anti-Alzheimer agents.

Natural Products as Potential Leads Against Coronaviruses: Could They be Encouraging Structural Models Against SARS-CoV-2?

New coronavirus referred to SARS-CoV-2 has caused a worldwide pandemic (COVID-19) declared by WHO. Coronavirus disease 2019 (COVID-19) is an infectious disease with severe acute respiratory syndrome caused by coronavirus-2 (SARS-CoV-2). SARS-CoV-2 is akin to SARS-CoV, which was the causative agent of severe acute respiratory syndrome (SARS) in 2002 as well as to that of Middle East respiratory syndrome (MERS) in 2012. SARS-CoV-2 has been revealed to belong to Coronaviridiae family as a member of ß-coronaviruses. It has a positive-sense single-stranded RNA with the largest RNA genome. Since its genomic sequence has a notable similarity to that of SARS-CoV, antiviral drugs used to treat SARS and MERS are now being also applied for COVID-19 treatment. In order to combat SARS-CoV-2, many drug and vaccine development studies at experimental and clinical levels are currently conducted worldwide. In this sense, medicinal plants and the pure natural molecules isolated from plants have been reported to exhibit significant inhibitory antiviral activity against SARS-CoV and other types of coronaviruses. In the present review, plant extracts and natural molecules with the mentioned activity are discussed in order to give inspiration to researchers to take these molecules into consideration against SARS-CoV-2.

Norditerpenoids with Selective Anti-Cholinesterase Activity from the Roots of Perovskia atriplicifolia Benth.

Inhibition of cholinesterases remains one of a few available treatment strategies for neurodegenerative dementias such as Alzheimer's disease and related conditions. The current study was inspired by previous data on anticholinesterase properties of diterpenoids from Perovskia atriplicifolia and other Lamiaceae species. The acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) inhibition by the three new natural compounds-(1R,15R)-1-acetoxycryptotanshinone (1), (1R)-1-acetoxytanshinone IIA (2), and (15R)-1-oxoaegyptinone A (3)-as well as, new for this genus, isograndifoliol (4) were assessed. Three of these compounds exhibited profound inhibition of butyrylcholinesterase (BChE) and much weaker inhibition of acetylcholinesterase (AChE). All compounds (1-4) selectively inhibited BChE (IC50 = 2.4, 7.9, 50.8, and 0.9 µM, respectively), whereas only compounds 3 and 4 moderately inhibited AChE (IC50 329.8 µM and 342.9 µM). Molecular docking and in silico toxicology prediction studies were also performed on the active compounds. Natural oxygenated norditerpenoids from the traditional Central Asian medicinal plant P. atriplicifolia are selective BChE inhibitors. Their high potential makes them useful candidate molecules for further investigation as lead compounds in the development of a natural drug against dementia caused by neurodegenerative diseases.

Novel pyridazinone derivatives as butyrylcholinesterase inhibitors.

In the current study, forty-four new [3-(2/3/4-methoxyphenyl)-6-oxopyridazin-1(6H)-yl]methyl carbamate derivatives were synthesized and evaluated for their ability to inhibit electric eel acetylcholinesterase (EeAChE) and equine butyrylcholinesterase (eqBuChE) enzymes. According to the inhibitory activity results, [3-(2-methoxyphenyl)-6-oxopyridazin-1(6H)-yl]methyl heptylcarbamate (16c, eqBuChE, IC50 = 12.8 µM; EeAChE, no inhibition at 100 µM) was the most potent eqBuChE inhibitor among the synthesized compounds and was found to be a moderate inhibitor compared to donepezil (eqBuChE, IC50 = 3.25 µM; EeAChE, IC50 = 0.11 µM). Kinetic and molecular docking studies indicated that compounds 16c and 14c (hexylcarbamate derivative, eqBuChE, IC50 = 35 µM; EeAChE, no inhibition at 100 µM) were mixed-type inhibitors which accommodated within the catalytic active site (CAS) and peripheral anionic site (PAS) of hBuChE through stable hydrogen bonding and π-π stacking. Furthermore, it was determined that [3-(2-methoxyphenyl)-6-oxopyridazin-1(6H)-yl]methyl (4-methylphenyl)carbamate 7c (eqBuChE, IC50 = 34.5 µM; EeAChE, 38.9% inhibition at 100 µM) was the most active derivative against EeAChE and a competitive inhibitor binding to the CAS of hBuChE. As a result, 6-(2-methoxyphenyl)pyridazin-3(2H)-one scaffold is important for the inhibitory activity and compounds 7c, 14c and 16c might be considered as promising lead candidates for the design and development of selective BuChE inhibitors for Alzheimer's disease treatment.

Profiling Auspicious Butyrylcholinesterase Inhibitory Activity of Two Herbal Molecules: Hyperforin and Hyuganin C.

Cholinergic therapy based on cholinesterase (ChE) inhibitory drugs is the mainstay for the treatment of Alzheimer's disease. Therefore, an extensive research has been continuing for the discovery of drug candidates as inhibitors of acetyl- and butyrylcholinesterase. In this study, two natural molecules, e. g. hyperforin and hyuganin C were tested in vitro for their AChE and BChE inhibitory activity. Both of the compounds were ineffective against AChE, whereas hyperforin (IC50 =141.60±3.39 µm) and hyuganin C (IC50 =38.86±1.69 µm) were found to be the highly active inhibitors of BChE as compared to galantamine (IC50 =46.58±0.91 µm) which was used as the reference. Then, these molecules were further proceeded to molecular docking experiments in order to establish their interactions at the active site of BChE. The molecular docking results indicated that both of them are able to block the access to key residues in the catalytic triad of the enzyme, while they complement some of the hydrophobic residues of the cavity, what is consistent with our in vitro data. While both compounds were predicted as mutagenic, only hyuganin C showed hepatotoxicity in in silico analysis. According to whole outcomes that we obtained, particularly hyuganin C besides hyperforin are the promising BChE inhibitors, which can be the promising compounds for AD therapy.

Combined molecular modeling and cholinesterase inhibition studies on some natural and semisynthetic O-alkylcoumarin derivatives.

Coumarins of synthetic or natural origins are an important chemical class exerting diverse pharmacological activities. In the present study, 26 novel O-alkylcoumarin derivatives were synthesized and have been tested at 100 µM for their in vitro inhibitory potential against acetylcholinesterase (AChE) and butyrlcholinesterase (BChE) targets which are the key enzymes playing role in the pathogenesis of Alzheimer's disease. Among the tested coumarins, none of them could inhibit AChE, whereas 12 of them exerted a marked and selective inhibition against BChE as compared to the reference (galanthamine, IC50 = 46.58 ±â€¯0.91 µM). In fact, 10 of the active coumarins showed higher inhibition (IC50 = 7.01 ±â€¯0.28 µM - 43.31 ±â€¯3.63 µM) than that of galanthamine. The most active ones were revealed to be 7-styryloxycoumarin (IC50 = 7.01 ±â€¯0.28 µM) and 7-isopentenyloxy-4-methylcoumarin (IC50 = 8.18 ±â€¯0.74 µM). In addition to the in vitro tests, MetaCore/MetaDrug binary QSAR models and docking simulations were applied to evaluate the active compounds by ligand-based and target-driven approaches. The predicted pharmacokinetic profiles of the compounds suggested that the compounds reveal lipophilic character and permeate blood brain barrier (BBB) and the ADME models predict higher human serum protein binding percentages (>50%) for the compounds. The calculated docking scores indicated that the coumarins showing remarkable BChE inhibition possessed favorable free binding energies in interacting with the ligand-binding domain of the target. Therefore, our results disclose that O-alkylcoumarins are promising selective inhibitors of cholinesterase enzymes, particularly BChE in our case, which definitely deserve further studies.