African Under-Utilized Medicinal Leafy Vegetables Studied by Microtiter Plate Assays and High-Performance Thin-Layer Chromatography-Planar Assays.

Biological activities of six under-utilized medicinal leafy vegetable plants indigenous to Africa, i.e., Basella alba, Crassocephalum rubens, Gnetum africanum, Launaea taraxacifolia, Solanecio biafrae, and Solanum macrocarpon, were investigated via two independent techniques. The total phenolic content (TPC) was determined, and six microtiter plate assays were applied after extraction and fractionation. Three were antioxidant in vitro assays, i.e., ferric reducing antioxidant power (FRAP), cupric reduction antioxidant capacity (CUPRAC), and 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging, and the others were enzyme (acetylcholinesterase, butyrylcholinesterase, and tyrosinase) inhibition assays. The highest TPC and antioxidant activity from all the methods were obtained from polar and medium polar fractions of C. rubens, S. biafrae, and S. macrocarpon. The highest acetyl- and butyrylcholinesterase inhibition was exhibited by polar fractions of S. biafrae, C. rubens, and L. taraxacifolia, the latter comparable to galantamine. The highest tyrosinase inhibition was observed in the n-butanol fraction of C. rubens and ethyl acetate fraction of S. biafrae. In vitro assay results of the different extracts and fractions were mostly in agreement with the bioactivity profiling via high-performance thin-layer chromatography-multi-imaging-effect-directed analysis, exploiting nine different planar assays. Several separated compounds of the plant extracts showed antioxidant, α-glucosidase, α-amylase, acetyl- and butyrylcholinesterase-inhibiting, Gram-positive/-negative antimicrobial, cytotoxic, and genotoxic activities. A prominent apolar bioactive compound zone was tentatively assigned to fatty acids, in particular linolenic acid, via electrospray ionization high-resolution mass spectrometry. The detected antioxidant, antimicrobial, antidiabetic, anticholinesterase, cytotoxic, and genotoxic potentials of these vegetable plants, in particular C. rubens, S. biafrae, and S. macrocarpon, may validate some of their ethnomedicinal uses.

Deciphering Neuroprotective Effect of Rosmarinus officinalis L. (syn. Salvia rosmarinus Spenn.) through Preclinical and Clinical Studies.

Rosmarinus officinalis L. (RO, rosemary) is a well-known medicinal, aromatic, and culinary herb with traditional use in European folk medicine against memory deficits and neurodegenerative disorders. This review highlights the different neuroprotective activities of RO investigated in both preclinical and clinical studies, as well as in silico molecular docking of bioactive compounds found in RO. The neuroprotective effect of RO was searched through databases including PubMed, Web of Science (WoS), Scopus, and Clinical Trials using the keywords "Rosmarinus officinalis, rosemary, neuroprotective effect, memory, cognitive dysfunction, Alzheimer's disease." RO, which is rich in secondary metabolites that have memory-enhancing potential, has displayed neuroprotection through different molecular mechanisms such as inhibition of cholinesterase, modulation of dopaminergic and oxytocinergic systems, mediation of oxidative and inflammatory proteins, involved in neuropathic pain, among others. RO extracts exhibited antidepressant and anxiolytic activities. Also, the plant has shown efficacy in scopolamine-, lipopolysaccharide-, AlCl3 -, and H2O2 -induced amnesia as well as amyloid-beta- and ibotenic acid-induced neurotoxicity and chronic constriction injury-related oxidative stress memory and cognitive impairments in animal models. A few clinical studies available supported the neuroprotective effects of RO and its constituents. However, more clinical studies are needed to confirm results from preclinical studies further and should include not only placebo-controlled studies but also studies including positive controls using approved drugs. Many studies underlined that constituents of RO may have the potential for developing drug candidates against Alzheimer's disease that possess high bioavailability, low toxicity, and enhanced penetration to CNS, as revealed from the experimental and molecular docking analysis.

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.

A Focused Review on Cognitive Improvement by the Genus Salvia L. (Sage)-From Ethnopharmacology to Clinical Evidence.

Ethnopharmacology has been an important starting point in medical and pharmaceutical sciences for discovering drug candidates from natural sources. In this regard, the genus Salvia L., commonly known as sage, is one of the best-known medicinal and aromatic plants of the Lamiaceae family; it has been recorded as being used for memory enhancement in European folk medicine. Despite the various uses of sage in folk medicines, the records that have pointed out sage's memory-enhancing properties have paved the way for the aforementioned effect to be proven on scientific grounds. There are many preclinical studies and excellent reviews referring to the favorable effect of different species of sage against the cognitive dysfunction that is related to Alzheimer's disease (AD). Hence, the current review discusses clinical studies that provide evidence for the effect of Salvia species on cognitive dysfunction. Clinical studies have shown that some Salvia species, i.e., hydroalcoholic extracts and essential oils of S. officinalis L. and S. lavandulaefolia leaves in particular, have been the most prominently effective species in patients with mild to moderate AD, and these species have shown positive effects on the memory of young and healthy people. However, the numbers of subjects in the studies were small, and standardized extracts were not used for the most part. Our review points out to the need for longer-term clinical studies with higher numbers of subjects being administered standardized sage preparations.

Medicinal and mechanistic overview of artemisinin in the treatment of human diseases.

Artemisinin (ART) is a bioactive compound isolated from the plant Artemisia annua and has been traditionally used to treat conditions such as malaria, cancer, viral infections, bacterial infections, and some cardiovascular diseases, especially in Asia, North America, Europe and other parts of the world. This comprehensive review aims to update the biomedical potential of ART and its derivatives for treating human diseases highlighting its pharmacokinetic and pharmacological properties based on the results of experimental pharmacological studies in vitro and in vivo. Cellular and molecular mechanisms of action, tested doses and toxic effects of artemisinin were also described. The analysis of data based on an up-to-date literature search showed that ART and its derivatives display anticancer effects along with a wide range of pharmacological activities such as antibacterial, antiviral, antimalarial, antioxidant and cardioprotective effects. These compounds have great potential for discovering new drugs used as adjunctive therapies in cancer and various other diseases. Detailed translational and experimental studies are however needed to fully understand the pharmacological effects of these compounds.

Absolute configuration of spiro-flavostilbenoids from Yucca schidigera Roezl ex Ortgies: First indication of (2R)-naringenin as the key building block.

The absolute configurations of the known but unusual spiro-flavostilbenoids found in the bark of Yucca schidigera Roezl ex Ortgies, were determined by applying time-dependent density functional theory simulation of electronic circular dichroism spectra. The absolute configurations obtained were as follows: (2S,3R) for yuccaol A, yuccaol D and yuccalide A; (2S,3S) for yuccaol B, yuccaol C and yuccaol E; (2S,3S,2'S,3'S) for gloriosaol A; (2S,3R,2'S,3'R) for gloriosaol C; (2S,3S,2'S,3'R) for gloriosaol D; (2S,3R,2'S,3'S) for gloriosaol E. These findings indicate that the compounds are all biosynthetic derivatives either of (2R)-naringenin and trans-resveratrol or of trans-3,3',5,5'-tetrahydroxy-4'-methoxystilbene. In contrast, gloriosaols are direct derivatives of yuccaols (note that substituting by stilbenoid changes the absolute configuration of C-2 naringenin carbon to 2S). A putative mechanism for their biosynthesis is proposed taking into account key aspects of regio- and stereoselectivity. Yuccaol B and gloriosaol A showed in vitro moderate inhibitory effects against acetyl-/butyrylcholinesterases (AChE/BChE) with IC50 values of 43/81 and 45/65 µM respectively. The selectivity index values calculated from the IC50 values of BChE and AChE were 1.9 and 1.4. Molecular docking simulations showed their interaction with the peripheral anionic site of human AChE and the catalytic site of the human BChE.

X-ray crystalographic data, absolute configuration, and anticholinesterase effect of dihydromyricitrin 3-O-rhamnoside.

Based on our continuous effort to investigate chemistry and biology of the plant secondary metabolites, we were able to isolate a glycosidal flavonoid 1 from the Wild Egyptian Artichoke. The activity of dihydromyricetin 3-O-rhamnoside (sin. dihydromyricitrin, ampelopsin 3-O-rhamnoside) (1) against acetylcholinesterase (AChE) and butyrylcholinesterase (BChE); its absolute configuration using X-ray crystallography were determined for the first time. Inhibitory activity of 1 against AChE and BChE enzymes were determined using a slightly modified version of Ellman's method. Compound 1 was revealed to have a potent inhibition against acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) with IC50 values of 0.070 ± 0.008 and 0.071 ± 0.004 mM, respectively, where IC50 values of the reference drug (galanthamine) were 0.023 ± 0.15 and 0.047 ± 0.91 mM. Compound 1 could be a promising molecule against Alzheimer's disease.

Phytochemical profiling, in vitro biological activity, docking studies, and cytotoxicity assessments of Rondeletia odorata Jacquin: An unexplored plant of the coffee family.

Rondeletia odorata Jacquin is a flowering plant that belongs to the coffee family. As a rich source of polyphenols with significant antioxidant potential, R. odorata may have health benefits. Therefore, in the current work, ethanolic extract of aerial parts and its n-hexane, ethyl acetate, and n-butanol soluble fractions were analyzed for their antioxidant potential and various enzyme inhibition properties. The total phenolic and flavonoid contents of the crude ethanol extract (ROE) and its n-hexane (ROH), ethyl acetate (ROEA), and n-butanol (ROB) fractions were determined spectrophotometrically, while metabolic profiling was established through UHPLC-MS analysis, which revealed the presence of 58 phytochemicals. Total phenolic and flavonoid contents of ROE extract were measured as 51.92 mg GA.Eq./g of dry extract and 52.35 mg Qu.Eq./g of the dry extract, respectively. In the DPPH radical scavenging activity assay, ROE and ROEA showed the highest potential with values of 62.13 ± 0.62 and 76.31% ± 1.86%, respectively, comparable to quercetin (80.89% ± 0.54%). Similarly, in the FRAP assay, the same pattern of the activity was observed with ROE and ROEA, which displayed absorbance values of 1.32 ± 0.01 and 0.80 ± 0.02 at 700 nm, respectively, which are comparable (1.76 ± 0.02) with the reference compound quercetin, whereas the ROH showed maximum metal-chelating capacity (62.61% ± 1.01%) among all extracts and fractions. Antibacterial activity assay indicated that the ROEA fraction was the most active against Serratia marcescens, Stenotrophomonas maltophilia, Bacillus subtilis, Klebsiella pneumonia, and Staphylococcus aureus, while the rest of the fractions showed good to moderate activity. Enzyme inhibition assays showed that ROEA fraction exhibited the highest activity with IC50 values of 2.78 ± 0.42 and 3.95 ± 0.13 mg/mL against urease and carbonic anhydrase (CA), respectively. Furthermore, the docking studies of some of the major compounds identified in the extract revealed a strong correlation with their inhibitory activity. All extracts and fractions were also tested for their thrombolytic activity, and the ROB fraction showed a notable potential. Antiviral assay led to remarkable outcomes. Thus, it can be inferred that aerial parts of R. odorata are potential sources of bioactive components with several significant pharmacological activities.

Chemical Composition, Antioxidant and Anti-Enzymatic Activity of Golden Root (Rhodiola rosea L.) Commercial Samples.

The aim of the study was to compare the chemical composition of the water and hydromethanolic extracts of R. rosea commercial samples in relation to their biological activity. For this purpose, the HPLC method was used for the determination of eleven phenolic compounds and AAS/AES was used for determination of five essential elements. Moreover, the contents of total phenolic, total flavonoid, total phenolic acids, and L(+)-ascorbic acid were determined. The antioxidant activity was assessed by DPPH (2,2-diphenyl-1-picrylhydrazyl) and ABTS radical scavenging activity, ferric-reducing/antioxidant power (FRAP), and cupric-reducing antioxidant capacity (CUPRAC) assays, while the inhibitory activity against AChE and BChE enzymes was determined using Ellman's method. The results showed that the hydromethanolic extracts of R. rosea were richer in phenolic compounds and showed higher antioxidant and neurobiological activity than the water extracts. However, the water extracts gave higher contents of determined elements. Among the individual phenolic compounds gallic acid (2.33 mg/g DW) and sinapic acid (386.44 µg/g DW) had the highest concentrations in the hydromethanolic and water extracts, respectively. Moreover, the most extracts were observed to be more efficient on BChE. Moreover, the correlation analysis indicated a high positive relationship between chemical composition and biological activity in both extracts of R. rosea.

Kombucha - An ancient fermented beverage with desired bioactivities: A narrowed review.

Kombucha, originated in China 2000  years ago, is a sour and sweet-tasted drink, prepared traditionally through fermentation of black tea. During the fermentation of kombucha, consisting of mainly acidic compounds, microorganisms, and a tiny amount of alcohol, a biofilm called SCOBY forms. The bacteria in kombucha has been generally identified as Acetobacteraceae. Kombucha is a noteworthy source of B complex vitamins, polyphenols, and organic acids (mainly acetic acid). Nowadays, kombucha is tended to be prepared with some other plant species, which, therefore, lead to variations in its composition. Pre-clinical studies conducted on kombucha revealed that it has desired bioactivities such as antimicrobial, antioxidant, hepatoprotective, anti-hypercholestorelomic, anticancer, anti-inflammatory, etc. Only a few clinical studies have been also reported. In the current review, we aimed to overhaul pre-clinical bioactivities reported on kombucha as well as its brief compositional chemistry. The literature data indicate that kombucha has valuable biological effects on human health.

Flavonoids as Sirtuin Modulators.

Sirtuins (SIRTs) are described as NAD+-dependent deacetylases, also known as class III histone deacetylases. So far, seven sirtuin genes (SIRTS 1-7) have been identified and characterized in mammals and are also known to occur in bacteria and eukaryotes. SIRTs are involved in various biological processes, including endocrine system, apoptosis, aging and longevity, diabetes, rheumatoid arthritis, obesity, inflammation, etc. Among them, the best-characterized one is SIRT1. Small molecules seem to be the most effective SIRT modulators. Flavonoids have been reported to possess many positive effects favorable for human health, while relatively less research has been reported so far on their functions as SIRT modulation mechanisms. In this regard, we aimed to focus on the modulatory effects of flavonoids on SIRTs as the most common secondary metabolites in natural products. Our literature survey covering the years from 2006 to 2021 pointed out that flavonoids frequently interact with SIRT1 and SIRT3, followed by SIRT6. It can also be concluded that some popular flavonoid derivatives, eg., resveratrol, quercetin, and catechin derivatives, came forward in terms of SIRT modulation.

7-Acetoxyhorminone from Salvia multicaulis Vahl. as Promising Inhibitor of 3-Hydroxy-3-methylglutaryl Coenzyme A (HMG-CoA) Reductase.

3-Hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase is a key enzyme involved in cholesterol biosynthesis and one of the most important targets for the treatment of hypercholesterolemia. A limited number of studies on the HMG-CoA reductase inhibitory potential of natural products are available. Thus, in the current study, we aimed to test the HMG-CoA reductase inhibitory capacity of extracts from the roots and aerial parts of Salvia multicaulis Vahl., through activity-guided isolation. Our findings revealed that the root extract prepared with dichloromethane-acetone (1:1) showed the highest inhibition (71.97 ± 0.37%) at 100 µg/mL. The extract was then initially fractionated by column chromatography and the obtained fractions were monitored by thin layer chromatography. Fractions which were similar to each other were combined and a total of 15 fractions were obtained. Further conventional chromatographic studies were carried out on the active fractions. Based on these fractions, 10 known compounds, comprising 9 terpenes and 1 steroid derivative in total, were isolated and their structures were verified by a combination of IT-TOF-MS, and 1D and 2D NMR techniques. According to the enzyme inhibition data of the identified compounds, 7-acetoxyhorminone exerted the highest inhibition (84.15 ± 0.10%, IC50 = 63.6 ± 1.21 µg/mL). The molecular docking experiments on 7-acetoxyhorminone and horminone indicated that both compounds strongly bind to the active site of the enzyme.

Antiproliferative and cytotoxic activity of Geraniaceae plant extracts against five tumor cell lines.

AIM: To determine the antiproliferative and cytotoxic activities of Geranium and Erodium species against human cancer and noncancer cell lines, respectively. METHODS: Twenty-one species of Geranium and Erodium were extracted and screened against cancerous and noncancerous human cell lines. RESULTS: In a dose-response manner, G. glaberrimum, G. asphodeloides, E. brandianum and E. leucanthum were able, with variable potency, to inhibit cellular proliferation. Except for E. brandianum, all extracts induced cellular autophagy in tumor cells with similar levels to that of rapamycin; but, only E. brandianum induced cellular apoptosis, likely through Bcl2 and BAX protein expressions. DISCUSSION: This is the first study to report the potential antiproliferative effects of ethanol extracts of several Geraniaceae species.

Oxyprenylated Secondary Metabolites as Modulators of Lipid and Sugar Metabolism.

O-Prenylcoumarins (3,3-dimethylallyl, geranyl-, farnesyl- and related biosynthetic derivatives) represent a class of rarely occurring natural compounds. Most of these secondary metabolites have been obtained from plant species belonging to the Rutaceae, Apiaceae, and Fabaceae families, and from fungi, and bacteria. In the last two decades, prenyloxycoumarins have been found to possess great potential in terms of pharmacological activities. The aim of this comprehensive review is to make a survey of the so far reported literature citations about these valuable phytochemicals and structurally related compounds about their modulatory properties of lipid and sugar metabolism. Literature data have been acquired from the main Internet database. Several oxyprenylated secondary metabolites have been surveyed. Among these, prenyloxycoumarins represented the main group displaying valuable effects as modulators of lipid and sugar metabolism. The title phytochemicals have been found in common fruits and vegetables already known to have beneficial effects, thus enforcing the nutraceutical role of these food plants. All compounds outlined in the present review article have a great potential in future for the prevention and management of acute and chronic metabolic disorders.

Natural Molecules as Talented Inhibitors of Nucleotide Pyrophosphatases/ Phosphodiesterases (PDEs).

BACKGROUND: Phosphodiesterases (PDEs) are a wide group of enzymes with multiple therapeutic actions, including vasorelaxation, cardiotonic, antidepressant, anti-inflammatory, antithrombotic, anti-spasmolytic, memory-enhancing, and anti-asthmatic. PDEs with eleven subtypes from PDE-1 to PDE-11 typically catalyze the cleavage of the phosphodiester bond and, hence, degrades either cyclic adenosine monophosphate (cAMP) or cyclic guanosine monophosphate (cGMP). OBJECTIVE: Several selective or non-selective inhibitors of the PDE subtypes are used clinically, i.e. sildenafil, rolipram, cysteine, etc. Recently, interest in plant-based pharmacologically bioactive compounds having potent PDEs inhibitory potential has increased. Purposely, extensive research has been carried out on natural products to explore new inhibitors of various PDEs. Therefore, this review summarizes the published data on natural PDEs inhibitors and their potential therapeutic applications. METHODS: For this purpose, natural compounds with PDE inhibitory potential have been surveyed through several databases, including PubMed, Web of Sciences (WoS), Scopus, and Google Scholar. RESULTS: According to a detailed literature survey, the most promising class of herbal compounds with PDE-inhibiting property has been found to belong to phenolics, including flavonoids (luteolin, kaempferol, icariin, etc.). Many other encouraging inhibitors from plants have also been identified, such as coumarins (23, 24) (licoarylcoumarin and glycocoumarin,), saponins (agapanthussaponins), lignans (31, 33) [(±)-schizandrin and kobusin], terpenes (28, 29, 31) (perianradulcin A, quinovic acid, and ursolic acid), anthraquinones (18, 19) (emodin and chrysophanol), and alkaloids (Sanjoinine-D) (36). CONCLUSION: In this review, studies have revealed the PDE-inhibitory potential of natural plant extracts and their bioactive constituents in treating various diseases; however, further clinical studies comprising synergistic use of different therapies (synthetic & natural) to acquire multi-targeted results might also be a promising option.

Profiling the annual change of the neurobiological and antioxidant effects of five Origanum species in correlation with their phytochemical composition.

The ethanol extracts of five Origanum species: O. majorana L., O. onites L., O. syriacum L., O. vulgare subsp. hirtum (Link) Ietsw., and O. vulgare subsp. viride (Boiss.) Hayek, collected annually (each month), were investigated for their cholinesterase inhibition and antioxidant effects. The phytochemical composition of a total of 60 extracts was assessed by HPLC-DAD-ESI/HRMS, revealing the presence of a total of 73 compounds. Possible correlation between the bioactivity and metabolite profiles during 12 months was monitored. Acetylcholinesterase (AChE) inhibitory activity was found to be the highest between April and November (50.29-75.95%, 200 µg/mL), while the highest inhibition towards butyrylcholinesterase (BChE) was observed for the extracts between April and October (71.68-88.97%). Aromadendrin showed good correlation with anti-AChE, anti-BChE and reducing power activities. Furthermore, molecular docking data with aromadendrin, caffeoylarbutin and eriodictyol indicated that caffeoylarbutin had the lowest binding energy against both enzymes.

The neuroprotective effects of polyphenols, their role in innate immunity and the interplay with the microbiota.

Neurodegenerative disorders, particularly in the elderly population, represent one of the most pressing social and health-care problems in the world. Besides the well-established role of both oxidative stress and inflammation, alterations of the immune response have been found to be closely linked to the development of neurodegenerative diseases. Interestingly, various scientific evidence reported that an altered gut microbiota composition may contribute to the development of neuroinflammatory disorders. This leads to the proposal of the concept of the gut-brain-immune axis. In this scenario, polyphenols play a pivotal role due to their ability to exert neuroprotective, immunomodulatory and microbiota-remodeling activities. In the present review, we summarized the available literature to provide a scientific evidence regarding this neuroprotective and immunomodulatory effects and the interaction with gut microbiota of polyphenols and, the main signaling pathways involved that can explain their potential therapeutic application in neurodegenerative diseases.

Preclinical Study on the Hepatoprotective Effect of Pollen Extract of Pinus brutia Ten. (Red Pine) in Mice and Phenolic Acid Analysis

Objectives: Many agents, including those from herbal sources, have been sought as preventives or cures for hepatotoxicity. The pollen of Pinus brutia Ten., known as red pine (Pinaceae), is used against liver diseases in Anatolian folk medicine. Materials and Methods: In the current study, pollen ethanol extract of P. brutia was investigated for its possible hepatoprotective activity using a mouse model of CCl4-induced hepatotoxicity. Swiss albino mice were divided into five groups, and extract-treated groups were compared with a silymarin-treated group as the reference. The extract was tested at 100, 200, and 300 mg/kg (b.w.). Phenolic acids were analyzed using high-performance column chromatography (HPLC) in the extracts as pollens are usually known to be rich in phenolics. Results: Our data revealed that the extract displayed the best hepatoprotection at a dose of 100 mg/kg when compared with silymarin (Legalon®), the reference drug. HPLC analysis indicated presence of protocatechuic acid (0.176 mg/g extract), p-hydroxybenzoic acid (0.001 mg/g extract), vanillic acid (VA) (0.537 mg/g extract), syringic acid (0.050 mg/g extract), and tr-cinnamic acid (0.310 mg/g extract), while the major phenolic acid was VA. Conclusion: The outcomes of this study allow us to conclude that red pine pollen extract can serve as a promising hepatoprotective agent. Among the phenolic acids analyzed in the pollen extract, vanillic acid as the major one besides some other phenolic acids detected seems to be responsible for its remarkable hepatoprotective effect.

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.