Discovery of Helminthosporin, an Anthraquinone Isolated from Rumex abyssinicus Jacq as a Dual Cholinesterase Inhibitor

Data Mining and in Silico Analysis of Ethiopian Traditional Medicine: Unveiling the Therapeutic Potential of Rumex abyssinicus Jacq

Multicomponent traditional medicine prescriptions are widely used in Ethiopia for disease treatment. However, inconsistencies across practitioners, cultures, and locations have hindered the development of reliable therapeutic medicines. Systematic analysis of traditional medicine data is crucial for identifying consistent and reliable medicinal materials. In this study, we compiled and analyzed a dataset of 505 prescriptions, encompassing 567 medicinal materials used for treating 106 diseases. Using association rule mining, we identified significant associations between diseases and medicinal materials. Notably, wound healing-the most frequently treated condition-was strongly associated with Rumex abyssinicus Jacq., showing a high support value. This association led to further in silico and network analysis of R. abyssinicus Jacq. compounds, revealing 756 therapeutic targets enriched in various KEGG pathways and biological processes. The Random-Walk with Restart (RWR) algorithm applied to the CODA PPI network identified these targets as linked to diseases such as cancer, inflammation, and metabolic, immune, respiratory, and neurological disorders. Many hub target genes from the PPI network were also directly associated with wound healing, supporting the traditional use of R. abyssinicus Jacq. for treating wounds. In conclusion, this study uncovers significant associations between diseases and medicinal materials in Ethiopian traditional medicine, emphasizing the therapeutic potential of R. abyssinicus Jacq. These findings provide a foundation for further research, including in vitro and in vivo studies, to explore and validate the efficacy of traditional and natural product-derived medicines.

Synthesis and Biological Evaluation of Colchicine─Aryl/Alkyl Amine Hybrids as Potential Noncytotoxic Cholinesterase Inhibitors: Identification of SBN-284 as a Dual Inhibitor of Cholinesterases and NLRP3 Inflammasome

Colchicine, one of the oldest anti-inflammatory natural products still used clinically, inhibits NF-κB signaling and NLRP3 inflammasome activation. Despite its cytotoxicity and narrow therapeutic range, colchicine continues to intrigue medicinal chemists exploring its anti-inflammatory potential. This study aimed to investigate the colchicine scaffold for its role in Alzheimer's disease by targeting neuroinflammation and cholinesterases. Molecular docking revealed that colchicine's hydrophobic trimethoxyphenyl framework can potentially bind to the peripheral anionic site of cholinesterases. Hybrid structures combining colchicine with aryl/alkyl amines were designed to bind both peripheral and catalytic sites of cholinesterases. We describe here the design, synthesis, and in vitro cytotoxicity evaluation of these colchicine-aryl/alkyl amine hybrids, along with their in silico interactions with the cholinesterase active site gorge. Nontoxic analogs demonstrating strong cholinesterase binding affinity were further evaluated for their anticholinesterase and antineuroinflammatory activities. The colchicine-donepezil hybrid, SBN-284 (3x), inhibited both acetylcholinesterase and butyrylcholinesterase as well as the NLRP3 inflammasome complex at low micromolar concentrations. It achieved this through noncompetitive inhibition, occupying the active site gorge and interacting with both peripheral and catalytic anionic sites of cholinesterases. Analog 3x was shown to cross the blood-brain barrier and exhibited no toxicity to neuronal cells, primary macrophages, or epithelial fR2 cells. These findings highlight the potential of this lead compound for further preclinical investigation as a promising anti-Alzheimer agent.

New opportunities and perspectives on biosynthesis and bioactivities of secondary metabolites from Aloe vera

Historically, the genus Aloe has been an indispensable part of both traditional and modern medicine. Decades of intensive research have unveiled the major bioactive secondary metabolites of this plant. Recent pandemic outbreaks have revitalized curiosity in aloe metabolites, as they have proven pharmacokinetic profiles and repurposable chemical space. However, the structural complexity of these metabolites has hindered scientific advances in the chemical synthesis of these compounds. Multi-omics research interventions have transformed aloe research by providing insights into the biosynthesis of many of these compounds, for example, aloesone, aloenin, noreugenin, aloin, saponins, and carotenoids. Here, we summarize the biological activities of major aloe secondary metabolites with a focus on their mechanism of action. We also highlight the recent advances in decoding the aloe metabolite biosynthetic pathways and enzymatic machinery linked with these pathways. Proof-of-concept studies on in vitro, whole-cell, and microbial synthesis of aloe compounds have also been briefed. Research initiatives on the structural modification of various aloe metabolites to expand their chemical space and activity are detailed. Further, the technological limitations, patent status, and prospects of aloe secondary metabolites in biomedicine have been discussed.

Experimental and pharmacoinformatic approaches unveil the neuropharmacological and analgesic potential of chloroform fraction of Roktoshirinchi (Achyranthes ferruginea Roxb.)

ETHNOPHARMACOLOGICAL RELEVANCE

Achyranthes ferruginea (A. ferruginea) Roxb. is a common plant used in traditional medicine in Asia and Africa. It has a variety of local names, including "Gulmanci" in Nigeria, "Dangar" in Pakistan, "Thola" in Ethiopia, and "Roktoshirinchi" in Bangladesh. It is edible and has several ethnomedical uses for a wide range of illnesses, including hysteria, dropsy, constipation, piles, boils, asthma, and shigellosis. However, the neuropharmacological and analgesic potential of A. ferruginea remains uninvestigated.

AIM OF THE STUDY

To assess the neuropharmacological and analgesic potential of A. ferruginea through a multifaceted approach encompassing both experimental and computational models.

MATERIALS AND METHODS

Methanol was used to extract the leaves of A. ferruginea. It was then fractionated with low to high polar solvents (n-hexane, chloroform, ethyl acetate, and water) to get different fractions, including chloroform fraction (CLF). The study selected CLF at different doses and conducted advanced chemical element and proximate analyses, as well as phytochemical profiling using GC-MS. Toxicological studies were done at 300 μg per rat per day for 14 days. Cholinesterase inhibitory potential was checked using an in-vitro colorimetric assay. Acetic acid-induced writhing (AAWT) and formalin-induced licking tests (FILT) were used to assess anti-nociceptive effects. The forced swim test (FST), tail suspension test (TST), elevated plus maze (EPM), hole board test (HBT), and light and dark box test (LDB) were among the behavioral tests used to assess depression and anxiolytic activity. Network pharmacology-based analysis was performed on selected compounds using the search tool for interacting chemicals-5 (STITCH 5), Swiss target prediction tool, and search tool for the retrieval of interacting genes and proteins (STRING) database to link their role with genes involved in neurological disorders through gene ontology and reactome analysis.

RESULTS

Qualitative chemical element analysis revealed the presence of 15 elements, including Na, K, Ca, Mg, P, and Zn. The moisture content, ash value, and organic matter were found to be 11.12, 11.03, and 88.97%, respectively. GC-MS data revealed that the CLF possesses 25 phytoconstituents. Toxicological studies suggested the CLF has no effects on normal growth, hematological and biochemical parameters, or cellular organs after 14 days at 300 μg per rat. The CLF markedly reduced the activity of both acetylcholinesterase and butyrylcholinesterase (IC50: 56.22 and 13.22 μg/mL, respectively). Promising dose-dependent analgesic activity (p < 0.05) was observed in chemically-induced pain models. The TST and FST showed a dose-dependent substantial reduction in immobility time due to the CLF. Treatment with CLF notably increased the number of open arm entries and time spent in the EPM test at doses of 200 and 400 mg/kg b.w. The CLF showed significant anxiolytic activity at 200 mg/kg b.w. in the HBT test, whereas a similar activity was observed at 400 mg/kg b.w. in the EPM test. A notable increase in the amount of time spent in the light compartment was observed in the LDB test by mice treated with CLF, suggesting an anxiolytic effect. A network pharmacology study demonstrated the relationship between the phytochemicals and a number of targets, such as PPARA, PPARG, CHRM1, and HTR2, which are connected to the shown bioactivities.

CONCLUSIONS

This study demonstrated the safety of A. ferruginea and its efficacy in attenuating cholinesterase inhibitory activity, central and peripheral pain, anxiety, and depression, warranting further exploration of its therapeutic potential.

Application of two-dimensional reversed phase countercurrent chromatography × high-performance liquid chromatography to bioactivity-guided screening and isolation of α-glucosidase inhibitors from Rheum palmatum L

In the present work, comprehensive two-dimensional reversed-phase countercurrent chromatography × reversed-phase liquid chromatography combined (2D RPCCC × RPLC) with 2D microfraction bioactive evaluation was employed to screen and isolate α-glucosidase inhibitors from Rheum palmatum L. Countercurrent chromatography was employed to improve 2D analysis and preparative separation. A selected biphasic solvent system composed of petroleum ether/ethyl acetate/methanol/water with gradient elution mode was used for the first dimension RPCCC separation (1D RPCCC). Solid-phase extraction was applied to eliminate interfering polar compounds before the second dimension analysis (2D RPLC). 76 components were shown in 2D contour plot in UV 280 nm. 11 Candidates were separated by a scaled-up CCC and identified by 1H NMR and 13C NMR, including anthraquinones, flavonoids, stilbenes, phenols, and glucoside derivatives. In addition, it was found that two components, resveratrol-4'-O-(6″-galloyl)glucoside (36) and lyciumaside (43) were identified as natural α-glucosidase inhibitors in Rheum palmatum L. for the first time.

Neuroprotective, Anti-Inflammatory and Antifibrillogenic Offerings by Emodin against Alzheimer's Dementia: A Systematic Review

Background: Alzheimer's disease (AD) is among the major causes of dementia in the elderly and exerts tremendous clinical, psychological and socio-economic constraints. Currently, there are no effective disease-modifying/retarding anti-AD agents. Emodin is a bioactive phytochemical with potent multimodal anti-inflammatory, antioxidant, and antifibrillogenic properties. In particular, emodin may result in significant repression of the pathogenic mechanisms underlying AD. The purpose of this review is to accumulate and summarize all the primary research data evaluating the therapeutic actions of emodin in AD pathogenesis. Methodology: The search, selection, and retrieval of pertinent primary research articles were systematically performed using a methodically designed approach. A variety of keyword combinations were employed on online scholarly web-databases. Strict preset inclusion and exclusion criteria were used to select the retrieved studies. Data from the individual studies were summarized and compiled into different sections, based upon their findings. Results: Cellular and animal research indicates that emodin exerts robust multimodal neuroprotection in AD. While emodin effectively prevents tau and amyloid-beta (Aβ) oligomerization, it also mitigates their neurotoxicity by attenuating neuroinflammatory, oxidative, and bioenergetic defects. Evidences for emodin-mediated enhancements in memory, learning, and cognition were also found in the literature. Conclusion: Emodin is a potential anti-AD dietary supplement; however, further studies are warrantied to thoroughly understand its target players and mechanisms. Moreover, human clinical data on emodin-mediated amelioration of AD phenotype is largely lacking, and must be addressed in the future. Lastly, the safety of exogenously supplemented emodin must be thoroughly evaluated.

Green approach to the synthesis of α-aminophosphonate-tetrahydroisoquinoline hybrids and their anti-cholinesterase activity

A series of 19 novel α-aminophosphonate-tetrahydroisoquinoline hybrids were synthesized through a cross dehydrogenative coupling reaction between N-aryl-tetrahydroisoquinolines and dialkylphosphites, using tert-butyl hydroperoxide as oxidazing agent. This simple procedure provided products with high atom economy and moderate to high yields. In vitro cholinesterase inhibitory activity of these compounds was evaluated. All the synthesized compounds showed good to excellent selective inhibition against butyrylcholinesterase. Compound 3bc was found to be the most active derivative with an IC50 of 9 nM. Molecular modelling studies suggested that the inhibitor is located in the peripheral anionic site (PAS) of the enzyme and interacts with some residue of the catalytic anionic site. Kinetic studies revealed that 3bc acts as a non-competitive inhibitor. Predicted ADME showed good pharmacokinetics and drug-likeness properties for most hybrids. Each newly synthesized compound was characterized by IR, 1H NMR, 13C NMR, 31P NMR spectral studies and also HRMS. The results of this study suggest that α-aminophosphonate-tetrahydroisoquinoline hybrids can be promising lead compounds in the discovery of new and improved drugs for the treatment of Alzheimer's disease and related neurodegenerative disorders.

DNA protection, molecular docking, antioxidant, antibacterial, enzyme inhibition, and enzyme kinetic studies for parietin, isolated from Xanthoria parietina (L.) Th. Fr

Parietin was isolated from Xanthoria parietina (L.) Th. Fr.' (methanol:chloroform) extract, using a silica column. 13 C NMR and 1H NMR were used to confirm the structure of the isolated parietin. For the first time, parietin was investigated for its antioxidant, antibacterial and DNA protective activities. Molecular docking was carried out to determine the binding affinity and interactions between the enzymes and our molecule. Inhibition and kinetic mechanism studies for the action of the enzymes were performed too. Parietin exhibited high metal chelating activity. The MIC values of parietin were sufficient to inhibit different bacterial strains; E. coli, P. aeruginosa, K. pneumoniae and S. aureus. Molecular docking applications exhibited that acetylcholinesterase (AChE), butyrylcholinesterase (BChE), lipase, and tyrosinase have high potential for binding with the parietin. Especially, the parietin's highest binding affinity was recorded with AChE and tyrosinase. These results were confirmed by the inhibition and kinetics results, where, parietin observed a potent inhibition with an IC50 values between 0.013-0.003 µM. Moreover, parietin acts' as a non-competitive inhibitor against AChE, BChE, and lipase, and as a competitive inhibitor against tyrosinase with a high rate of inhibition stability. The promising biological properties of parietin revealed its effectiveness in terms of suitability in the food and pharmaceutical industries.Communicated by Ramaswamy H. Sarma.

Naturally Occurring Cholinesterase Inhibitors from Plants, Fungi, Algae, and Animals: A Review of the Most Effective Inhibitors Reported in 2012-2022

Since the development of the "cholinergic hypothesis" as an important therapeutic approach in the treatment of Alzheimer's disease (AD), the scientific community has made a remarkable effort to discover new and effective molecules with the ability to inhibit the enzyme acetylcholinesterase (AChE). The natural function of this enzyme is to catalyze the hydrolysis of the neurotransmitter acetylcholine in the brain. Thus, its inhibition increases the levels of this neurochemical and improves the cholinergic functions in patients with AD alleviating the symptoms of this neurological disorder. In recent years, attention has also been focused on the role of another enzyme, butyrylcholinesterase (BChE), mainly in the advanced stages of AD, transforming this enzyme into another target of interest in the search for new anticholinesterase agents. Over the past decades, Nature has proven to be a rich source of bioactive compounds relevant to the discovery of new molecules with potential applications in AD therapy. Bioprospecting of new cholinesterase inhibitors among natural products has led to the discovery of an important number of new AChE and BChE inhibitors that became potential lead compounds for the development of anti-AD drugs. This review summarizes a total of 260 active compounds from 142 studies which correspond to the most relevant (IC50 ≤ 15 μM) research work published during 2012-2022 on plant-derived anticholinesterase compounds, as well as several potent inhibitors obtained from other sources like fungi, algae, and animals.

Quinones: Biosynthesis, Characterization of 13 C Spectroscopical Data and Pharmacological Activities

Quinones are natural products widely distributed in nature, which are involved in stages of several vital biological processes, with mostly having a variety of pharmacological properties. The main groups comprising most of these compounds are benzoquinones, naphthoquinones, anthraquinones, and phenanthraquinones. Quinone isolation has been a focus of study around the world in recent years; for this reason, this study approaches the junction of natural quinones identified by 13 C Nuclear Magnetic Resonance (NMR) spectroscopic analytical techniques. The methodology used to obtain the data collected articles from various databases on quinones from 2000 to 2022. As a result, 137 compounds were selected, among which 70 were characterized for the first time in the period investigated; moreover, the study also discusses the biosynthetic pathways of quinones and the pharmacological activities of the compounds found, giving an overview of the various applications of these compounds.

Antibacterial constituents of Rumex nepalensis spreng and its emodin derivatives

The CH2Cl2-MeOH (1:1) extract of roots of Rumex nepalensis (Polygonaceae) displayed significant antibacterial activity against five bacterial strains with MICs (62.5-31.2 μg.mL-1). The EtOAc soluble fraction displayed a significant activity against the same strains with MICs (31.2-3.9 μg.mL-1). The purification of the EtOAc fraction yielded one new phenylisobenzofuranone derivative, berquaertiide (1), along with 19 known compounds (2-20). Their structures were elucidated based on the analysis of their NMR and MS data. All the isolated compounds were assessed for their antibacterial activity. Compound 2 was the most active against all the tested strains (15.7 to 1.9 μg.mL-1), while compounds 3-7 displayed good activities on at least one of the tested strains. In addition, seven analogues (21-27) of compound 2 were prepared and further assessed for their antibacterial activity. Compounds 26 and 27 were most active than 2 against Salmonella enterica and Klebsiella pneumoniae with MIC (125 and 15.6 μg.mL-1, respectively).

A Review of the Chemistry and Biological Activities of Natural Colorants, Dyes, and Pigments: Challenges, and Opportunities for Food, Cosmetics, and Pharmaceutical Application

Natural pigments are important sources for the screening of bioactive lead compounds. This article reviewed the chemistry and therapeutic potentials of over 570 colored molecules from plants, fungi, bacteria, insects, algae, and marine sources. Moreover, related biological activities, advanced extraction, and identification approaches were reviewed. A variety of biological activities, including cytotoxicity against cancer cells, antioxidant, anti-inflammatory, wound healing, anti-microbial, antiviral, and anti-protozoal activities, have been reported for different pigments. Considering their structural backbone, they were classified as naphthoquinones, carotenoids, flavonoids, xanthones, anthocyanins, benzotropolones, alkaloids, terpenoids, isoprenoids, and non-isoprenoids. Alkaloid pigments were mostly isolated from bacteria and marine sources, while flavonoids were mostly found in plants and mushrooms. Colored quinones and xanthones were mostly extracted from plants and fungi, while colored polyketides and terpenoids are often found in marine sources and fungi. Carotenoids are mostly distributed among bacteria, followed by fungi and plants. The pigments isolated from insects have different structures, but among them, carotenoids and quinone/xanthone are the most important. Considering good manufacturing practices, the current permitted natural colorants are: Carotenoids (canthaxanthin, β-carotene, β-apo-8'-carotenal, annatto, astaxanthin) and their sources, lycopene, anthocyanins, betanin, chlorophyllins, spirulina extract, carmine and cochineal extract, henna, riboflavin, pyrogallol, logwood extract, guaiazulene, turmeric, and soy leghemoglobin.

Antileishmanial anthraquinones from the rhyzomes of Rumex abyssinicus Jacq (Polygonaceae)

Phytochemical investigation of the rhyzomes of Rumex abyssinicus (Polygonaceae) afforded six anthraquinones viz chrysophanol (1), physcion (2), emodin (3), mixture of physcion-8-O-β,D-glucopyranoside (4) and chrypsophanol-8-O-β,D-glucopyranoside (5), and emodin-8-O-β,D-glucopyranoside (6). All the compounds were characterised and identified by comparison of their MS and NMR data with available literature data. The isolated compounds were evaluated for their antileishmanial activity. Emodin (3) was the most active compounds with IC50 13.82 and 0.26 µg/mL against Leishmania donovani amastigotes and promastigotes, respectively. Emodin-8-O-β,D-glucopyranoside (6) also showed a moderate activity with IC50 27.53 and 37.08 µg/mL. This is the first report of antileishmanial compounds from R. abyssinicus and the antileishmanial activities of compounds 2, 4, 5 and 6 are here reported for the first time.

Nutritional and medicinal plants as potential sources of enzyme inhibitors toward the bioactive functional foods: an updated review

Enzymes are biologically active complex protein molecules that catalyze most chemical reactions in living organisms, and their inhibitors accelerate biological processes. This review emphasizes medicinal food plants and their isolated chemicals inhibiting clinically important enzymes in common diseases. A mechanistic overview was investigated to explain the mechanism of these food bases enzyme inhibitors. The enzyme inhibition potential of medicinal food plants and their isolated substances was searched in Ovid, PubMed, Science Direct, Scopus, and Google Scholar. Cholinesterase, amylase, glucosidase, xanthine oxidase, tyrosinase, urease, lipoxygenase, and others were inhibited by crude extracts, solvent fractions, or isolated pure chemicals from medicinal food plants. Several natural compounds have shown tyrosinase inhibition potential, including quercetin, glabridin, phloretin-4-O-β-D-glucopyranoside, lupinalbin, and others. Some of these compounds' inhibitory kinetics and molecular mechanisms are also discussed. Phenolics and flavonoids inhibit enzyme activity best among the secondary metabolites investigated. Several studies showed flavonoids' significant antioxidant and anti-inflammatory activities, highlighting their medicinal potential. Overall, many medicinal food plants, their crude extracts/fractions, and isolated compounds have been studied, and some promising compounds depending on the enzyme have been found. Still, more studies are recommended to derive potential pharmacologically active functional foods.

Methoxy-naphthyl-Linked N-Benzyl Pyridinium Styryls as Dual Cholinesterase Inhibitors: Design, Synthesis, Biological Evaluation, and Structure-Activity Relationship

The multifaceted nature of Alzheimer's disease (AD) indicates the need for multitargeted agents as potential therapeutics. Both cholinesterases (ChEs), acetylcholinesterase (AChE) and butyrylcholinesterase (BChE), play a vital role in disease progression. Thus, inhibiting both ChEs is more beneficial than only one for effectively managing AD. The present study provides a detailed lead optimization of the e-pharmacophore-generated pyridinium styryl scaffold to discover a dual ChE inhibitor. A structure-activity relationship analysis indicated the importance of three structural fragments, methoxy-naphthyl, vinyl-pyridinium, and substituted-benzyl, in a dual ChE inhibitor pharmacophore. The optimized 6-methoxy-naphthyl derivative, 7av (SB-1436), inhibits EeAChE and eqBChE with IC₅₀ values of 176 and 370 nM, respectively. The kinetic study has shown that 7av inhibits AChE and BChE in a non-competitive manner with k_i values of 46 and 115 nM, respectively. The docking and molecular dynamics simulation demonstrated that 7av binds with the catalytic and peripheral anionic sites of AChE and BChE. Compound 7av also significantly stops the self-aggregation of Aβ. The data presented herein indicate the potential of 7av for further investigation in preclinical models of AD.

Synthesis and Biological Evaluation of Coumarin Triazoles as Dual Inhibitors of Cholinesterases and β-Secretase

Coumarin is a naturally occurring bioactive pharmacophore with wide occurrence among central nervous system (CNS)-active small molecules. 8-Acetylcoumarin, one of the natural coumarins, is a mild inhibitor of cholinesterases and β-secretase, which are vital targets of Alzheimer's disease. Herein, we synthesized a series of coumarin-triazole hybrids as potential multitargeted drug ligands (MTDLs) with better activity profiles. The coumarin-triazole hybrids occupy the cholinesterase active site gorge from the peripheral to the catalytic anionic site. The most active analogue, 10b, belonging to the 8-acetylcoumarin core, inhibits acetylcholinesterase (AChE), butyrylcholinesterase (BChE), and β-secretase-1 (BACE-1) with IC₅₀ values of 2.57, 3.26, and 10.65 μM, respectively. The hybrid, 10b, crosses the blood-brain barrier via passive diffusion and inhibits the self-aggregation of amyloid-β monomers. The molecular dynamic simulation study reveals the strong interaction of 10b with three enzymes and forming stable complexes. Overall, the results warrant a detailed preclinical investigation of the coumarin-triazole hybrids.

Design, Synthesis, and Pharmacological Evaluation of Embelin-Aryl/alkyl Amine Hybrids as Orally Bioavailable Blood-Brain Barrier Permeable Multitargeted Agents with Therapeutic Potential in Alzheimer's Disease: Discovery of SB-1448

The complex and multifaceted nature of Alzheimer's disease has brought about a pressing demand to develop ligands targeting multiple pathways to combat its outrageous prevalence. Embelin is a major secondary metabolite of Embelia ribes Burm f., one of the oldest herbs in Indian traditional medicine. It is a micromolar inhibitor of cholinesterases (ChEs) and β-site amyloid precursor protein cleaving enzyme 1 (BACE-1) with poor absorption, distribution, metabolism, and excretion (ADME) properties. Herein, we synthesize a series of embelin-aryl/alkyl amine hybrids to improve its physicochemical properties and therapeutic potency against targeted enzymes. The most active derivative, 9j (SB-1448), inhibits human acetylcholinesterase (hAChE), human butyrylcholinesterase (hBChE), and human BACE-1 (hBACE-1) with IC₅₀ values of 0.15, 1.6, and 0.6 μM, respectively. It inhibits both ChEs noncompetitively with k_i values of 0.21 and 1.3 μM, respectively. It is orally bioavailable, crosses blood-brain barrier (BBB), inhibits Aβ self-aggregation, possesses good ADME properties, and protects neuronal cells from scopolamine-induced cell death. The oral administration of 9j at 30 mg/kg attenuates the scopolamine-induced cognitive impairments in C57BL/6J mice.

Isolation and characterisation of pharmaceutically versatile molecules from Rumex dentatus and evaluation of their cytotoxic activity against human cancer cell lines

The disclosed study reveals isolation, characterization and anticancer evaluation of Rumex dentatus. The extracts and isolated compounds were used for cytotoxic activity against (lung (A549), pancreatic (MIAPaCa), colon (HCT-116), breast (MDA-MB-231) and breast (MDA-MB-468) cell lines. The extracts were screened for cytotoxicity using MTT colorimetric assay. Out of all extracts, methanolic (30) %: chloroform fraction (TAW6) with 75.01% inhibition at a concentration 100 µg/mL was observed. The selected extracts were further processed for column chromatography and led to isolation of seven compounds (A to G). The structural determination of isolated compounds was carried out using ¹HNMR, ¹³CNMR, IR and HRMS. All the isolates were tested for cytotoxic activity and compound B was found most active with IC₅₀ values 11.29 µg against HCT-116 (Colon). The compound B was then used for detailed study via transwell invasion assay and wound healing assay. Thus the significant anticancer activity particularly against colon cancerous cell lines recommends that the (Rumex dentatus) could act as a potential drug candidate for cancer, more particularly for colon cancer.

Traditional Herbal Remedies in the Management of Metabolic Disorders in Ethiopia: A Systematic Review of Ethnobotanical Studies and Pharmacological Activities

Background

MetS are common throughout the world, including Ethiopia. These have traditionally been treated using medicinal plants, particularly in rural areas where they are freely accessible. This systematic review tried to investigate the treatment of MetS with Ethiopian medicinal herbs and made recommendations for more validation research. A careful analysis of the literature was also conducted on the therapeutic effects of these and other Ethiopian medicinal plants with hepatoprotective and antihypertensive activities.

Methods

The relevant keywords "Ethnomedicinal + hypertension," "Ethnopharmacological + hypertension," "Ethnomedicinal + hepatitis, jaundices, and liver disease," "Ethnopharmacological + hepatic disorder," and "Ethnomedicinal + weight loss" were used to search for relevant articles in the major electronic scientific databases, including PubMed, Science Direct, Web of Science, and Google Scholar. The search strategy included all articles with descriptions that were accessible until April 30, 2022. The study's subjects, methods, or year of publication were no restrictions in the search. The outcomes were compiled using descriptive statistics.

Results

Fifty-four (54) studies were examined in the review that satisfied the inclusion and exclusion criteria for the treatment of MetS in Ethiopia. The most often used ethnobotanical plant species for the treatment of hypertension and hepatic disorders were Moringa stenopetala and Croton macrostachyus. Both hepatic and hypertensive disorders were treated more frequently with leaves (52% and 39%, respectively) than with roots (20% and 13%, respectively). Some intriguing studies came from an ethnobotanical investigation into medicinal herbs' hepatoprotective and antihypertensive properties. The most often investigated medicinal plant for its antihypertensive effects is Moringa stenopetala.

Conclusion

The study revealed that Ethiopians often use anti-MetS herbal remedies. We advocate the experimental validation of the commonly used medicinal plants with the identification of active compounds and the development of effective alternative drugs for the treatment of MetS.

Discovery of Pongol, the Furanoflavonoid, as an Inhibitor of CDK7/Cyclin H/MAT1 and Its Preliminary Structure-Activity Relationship

Natural products have been a great source of leads for cancer drug discovery. The cyclin-dependent kinases (CDKs) play a vital role in the initiation and progression of cancer. The CDK-activating kinase, CDK7/cyclin H/MAT1, has recently gained tremendous attention in targeted cancer drug discovery. Herein, we screened a small library of pure natural products in an ADP-Glo CDK7/H kinase assay that yielded a series of furano- and naphthoflavonoids among actives. Pongol (SBN-88), the hydroxy-substituted furanoflavonoid, inhibits CDK7/H as well as CDK9/T1 with IC₅₀ values of 0.93 and 0.83 μM, respectively, and >20-fold selectivity over CDK2/E1 (IC₅₀ > 20 μM). The molecular docking and molecular dynamics simulation revealed that the presence of phenolic -OH in pongol is vital for kinase inhibition, as its absence resulted in a significant loss in activity (e.g., lanceolatin B). The prime MM-GBSA calculations revealed the presence of strong lipophilic and H-bonding interactions of pongol with CDKs.

Medicinal uses, chemical constituents and biological activities of Rumex abyssinicus: A Comprehensive review

Rumex abyssinicus is a valuable medicinal plant species that is native to tropical Africa. Traditionally, R. abyssinicus is used to treat different disease such as, liver diseases, hepatitis, malaria, scabies, blood pressure, jaundice, wound and pneumonia. The purpose of the current study was to review the literature on the ethnomedicinal uses, chemical constitutes and biological activities of R. abyssinicus in an attempt to create information for future studies aimed towards exploring the therapeutic ability of the species. A scientific search engines, namely Google Scholar, PubMed, Scopus, Science Direct and Web of knowledge for the search terms: Rumex abyssinicus, ethnomedicinal studies, phytochemical investigations, and pharmacological activities were undertaken. The search strategy included all articles with descriptors that were available until December 30, 2021. Only published works in English have been used on this study. The data was collected using textual descriptions of the studies, tabulation, grouping, and figures. The principal phytochemicals of R. abyssinicus are anthraquinones, flavonoids, terepenoids and phenolic compounds. The in vitro and in vivo studies on the crude extracts and compounds of R. abyssinicus showed antibacterial, antioxidant, anticancer, anti-inflammatory, antifungal, wound healing, antialzeimer’s and hepatoprotective activities of it. R. abyssinicus afforded drug leads such as helminthosporin (4) with anti-alzheimer and physicon (3) with antifungal and antioxidant activity. R. abyssinicus have traditionally been used to cure a variety of diseases. Pharmacological actions of phytochemicals were shown to be promising. Despite this, further studies on crude extracts and promising compounds are needed to find new drug candidates.

Antimicrobial and Cytotoxic Potential of Helminthosporin from Rumex abyssiniscus Jacq. Discovered as a Novel Source of Syringic Acid and Bis(2-ethyloctyl) Phthalate

Rumex abyssinicus Jacq. is a perennial medicinal herb widely used in traditional medicine to treat many diseases. Phytochemicals of the plant were isolated using column chromatography and thin layer chromatography techniques. Extract, fractions and pure compounds were screened for antimicrobial activity against sensitive and multi-drug resistant microbes and their cytotoxicity was performed on different cancer cell lines. The mechanism of action of purified helminthosporin as well as the potent fraction containing a mixture of two compounds was assessed. Fraction R7C3 was the most potent antibacterial with the lowest MIC value of 0.12 µg/mL. Helminthosporin was the most potent compound with the lowest MIC value of 1.95 µg/mL. The compound was more potent than the antibiotic chloramphenicol against multi-drug resistant (MDR) bacteria with MIC equal to 16 µg/mL. The fraction and helminthosporin were shown to destroy the cell wall of the yeast and bacteria, and DNA fragmentation effect on the genome of Candida albicans and Bacillus cereus. Helminthosporin was the most cytotoxic compound with IC₅₀ ˂ 10 µM. Fraction R7C3 showed the most potent cytotoxic effects on all cancer cell lines, with IC₅₀ ranging from ˂1 to 4.35 ng/mL. Our study is the first report on the mechanism of action of helminthosporin, a potent candidate in the development of new drugs against multi-resistant bacteria and cancer cells. In addition, this study uncovered Rumex abyssinicus as a new source of syringic acid and bis(2-ethyloctyl) phthalate.

Design, synthesis, in-vitro, in-vivo and ex-vivo pharmacology of thiazolidine-2,4-dione derivatives as selective and reversible monoamine oxidase-B inhibitors

Neurodegenerative ailments are a diverse set of syndromes distinguished by gradual deterioration of the structure as well as functions of the central nervous system or peripheral nervous system. Alzheimer's disease (AD) and Parkinson's disease (PD) have no cure, common, and are high prevalent neurodegenerative pathologies. In current research, rationally designed thiazolidine-2,4-dione based analogs were synthesized and tested for their inhibition potential against two isoforms of monoamine oxidase (MAO-A / MAO-B). Structure activity relationships were explored. Pyridinyl and thiazolyl hydrazone derivative 43 and 44 with IC₅₀ value of 0.013 µM and 0.008 µM (selectivity 228 / 226 times) exhibited higher potency than reference drug safinamide. Most active compounds showed BBB penetration in PAMPA in-vitro assay. Except nitro derivative 41, all compounds were non-neurotoxic in the studied concentration. Molecular docking studies supported the in-vitro experimental results and the selectivity by comparing the binding energy values against both MAO-A and MAO-B isoforms. All the results of current research suggest compounds 43 and 44 may serve as promising candidates for further research for treatment of neurodegenerative diseases.

Bioactive Metabolite Production in the Genus Pyrenophora (Pleosporaceae, Pleosporales)

The genus Pyrenophora includes two important cereal crop foliar pathogens and a large number of less well-known species, many of which are also grass pathogens. Only a few of these have been examined in terms of secondary metabolite production, yet even these few species have yielded a remarkable array of bioactive metabolites that include compounds produced through each of the major biosynthetic pathways. There is little overlap among species in the compounds identified. Pyrenophora tritici-repentis produces protein toxin effectors that mediate host-specific responses as well as spirocyclic lactams and at least one anthraquinone. Pyrenophora teres produces marasmine amino acid and isoquinoline derivatives involved in pathogenesis on barley as well as nonenolides with antifungal activity, while P. semeniperda produces cytochalasans and sesquiterpenoids implicated in pathogenesis on seeds as well as spirocyclic lactams with phytotoxic and antibacterial activity. Less well-known species have produced some unusual macrocyclic compounds in addition to a diverse array of anthraquinones. For the three best-studied species, in silico genome mining has predicted the existence of biosynthetic pathways for a much larger array of potentially toxic secondary metabolites than has yet been produced in culture. Most compounds identified to date have potentially useful biological activity.

Molecular interactions of niclosamide with hydroxyethyl cellulose in binary and ternary amorphous solid dispersions for synergistic enhancement of water solubility and oral pharmacokinetics in rats

The cellulose-based polymers are extensively employed in oral formulations for addressing ADMET issues of API. Herein, we report the synergistic effect of hydroxyethyl cellulose in solubility/dissolution enhancement of BCS class II, anthelmintic drug niclosamide. The low solubility and poor oral bioavailability are the primary reasons for its high daily dose. The amorphous solid dispersions (ASDs) developed herein demonstrated reproducible solubility and dissolution enhancement in smaller-to-pilot batches. The significant boost in niclosamide solubility in HEC-based binary SD was rationalized as a result of intermolecular H-bonding as indicated by in-silico studies and further supported by characterization data. HEC is plausibly inhibiting the precipitation of drug and thereby enabling high dissolution and permeation across the membrane. The comparative oral pharmacokinetics in Wistar rats at 25 mg/kg provided 4.4-fold higher plasma exposure of niclosamide in SD formulation SB-ASD-N2 over the plain drug. The results presented herein warrant validation of this ASD under clinical settings. Teaser Amorphous solid dispersions of niclosamide.

Diclofenac derivatives as concomitant inhibitors of cholinesterase, monoamine oxidase, cyclooxygenase-2 and 5-lipoxygenase for the treatment of Alzheimer's disease: synthesis, pharmacology, toxicity and docking studies

Targeting concomitantly cholinesterase (ChEs) and monoamine oxidases (MAO-A and MAO-B) is a key strategy to treat multifactorial Alzheimer's disease (AD). Moreover, it is reported that the expression of cyclooxygenase-2 (COX-2) and lipoxygenase (LOX) is increased significantly in the brain of AD patients. Using the triazole of diclofenac 12 as a lead compound, we synthesized a variety of analogs as multipotent inhibitors concomitantly targeting COX-2, 5-LOX, AChE, BChE, MAO-A and MAO-B. A number of compounds showed excellent in vitro inhibition of the target biological macromolecules in nanomolar concentration. Compound 39 emerged as the most potent multitarget ligand with IC50 values of 0.03 μM, 0.91 μM, 0.61 μM, 0.01 μM 0.60 μM and 0.98 μM towards AChE, BChE, MAO-A, MAO-B, COX-2 and 5-LOX respectively. All the biologically active compounds were found to be non-neurotoxic and blood-brain barrier penetrant by using PAMPA assay. In a reversibility assay, all the studied active compounds showed reversibility and thus were found to be devoid of side effects. MTT assay results on neuroblastoma SH-SY5Y cells showed that the tested compounds were non-neurotoxic. An in vivo acute toxicity study showed the safety of the synthesized compounds up to a 2000 mg kg-1 dose. In docking studies three-dimensional construction and interaction with key residues of all the studied biological macromolecules helped us to explain the experimental results.

New seco-anthraquinone glucoside from the roots of Rumex crispus

A new seco-anthraquinone, crispuside A (1), and three new 3,4-dihydronaphthalen-1(2H)-ones, napthalenones A-C (2-4), were isolated from the roots of Rumex crispus L., along with 10 known anthraquinones (6-14) and naphthalenone (5). Their structures were fully determined by extensive spectroscopic analyses, including ECD, and X-ray crystallography in case of compound 5, whose absolute configuration was determined for the first time. The isolates 1, 6-14 were evaluated for their anti-inflammatory and anti-fungal activity against three skin fungi, e.g., Epidermophyton floccosum, Trichophyton rubrum, and Microsporum gypseum. Most of the isolates showed weak anti-fungal and anti-inflammatory activity. Only compound 9 exhibited obvious anti-fungal activity against E. floccosum (MIC₅₀ = 2.467 ± 0.03 μM) and M. gypseum (MIC₅₀ = 4.673 ± 0.077 μM), while the MIC₅₀ values of the positive control terbinafine were 1.287 ± 0.012 and 0.077 ± 0.00258 μM, respectively. The results indicated that simple emodin type anthraquinone is more potential against skin fungi than its oxyglucosyl, C-glucosyl and glycosylated seco analogues.

A Coumarin-donepezil Hybrid as a Blood-brain Barrier Permeable Dual Cholinesterase Inhibitor: Isolation, Synthetic Modifications and Biological Evaluation of Natural Coumarins

Plants have immensely contributed to the drug discovery for neurodegenerative diseases. Herein, we undertook the phytochemical investigation of Nardostachys jatamansi (D.Don) DC. rhizomes followed by semisynthetic modifications to discover cholinesterase (ChE) and beta-site amyloid precursor protein cleaving enzyme 1 (BACE-1) inhibitors. The 8-acetyl-7-hydroxycoumarin isolated from the bioactive extract moderately inhibits acetylcholinesterase (AChE) and BACE-1 with IC50 values of 22.1 and 17.7 μM, respectively. The semisynthetic trifluoromethyl substituted coumarin chalcone display a 5-fold improvement in BACE-1 inhibition (IC50 3.3 μM). Another semisynthetic derivative, a coumarin-donepezil hybrid, exhibits dual inhibition of both ChEs with IC50 values of 1.22 and 3.09 μM, respectively. Molecular modeling and enzyme kinetics revealed that the coumarin-donepezil hybrid is a non-competitive inhibitor of AChE. It crosses the blood-brain barrier and also inhibits Aβ self-aggregation. The results presented herein warrant a detailed investigation of the coumarin-donepezil hybrid in preclinical models of Alzheimer's disease.

The genus Rumex (Polygonaceae): an ethnobotanical, phytochemical and pharmacological review

Rumex L., a genus in Polygonaceae family with about 200 species, is growing widely around the world. Some Rumex species, called "sorrel" or "dock", have been used as food application and treatment of skin diseases and hemostasis after trauma by the local people of its growing areas for centuries. To date, 29 Rumex species have been studied to contain about 268 substances, including anthraquinones, flavonoids, naphthalenes, stilbenes, diterpene alkaloids, terpenes, lignans, and tannins. Crude extract of Rumex spp. and the pure isolates displayed various bioactivities, such as antibacterial, anti-inflammatory, antitumor, antioxidant, cardiovascular protection and antiaging activities. Rumex species have important potential to become a clinical medicinal source in future. This review covers research articles from 1900 to 2022, fetched from SciFinder, Web of Science, ResearchGate, CNKI and Google Scholar, using "Rumex" as a search term ("all fields") with no specific time frame set for the search. Thirty-five Rumex species were selected and summarized on their geographical distribution, edible parts, traditional uses, chemical research and pharmacological properties.

Design, Synthesis, and Bioevaluation of Indole Core Containing 2-Arylidine Derivatives of Thiazolopyrimidine as Multitarget Inhibitors of Cholinesterases and Monoamine Oxidase A/B for the Treatment of Alzheimer Disease

In continuation of our previous study to identify multitarget inhibitors of cholinesterases (ChEs) and monoamine oxidase (MAOs) isoforms, we synthesized and evaluated 2-arylidine derivatives of thiazolopyrimidine for the treatment of Alzheimer disease. Three series of compounds with different linker size and target-anchoring functional groups were synthesized. Compounds 34-37 showed excellent to good AChE and BChE inhibition potential at nanomolar to low micromolar concentration. While all the compounds showed excellent MAO-B inhibition and selectivity relative to MAO-A, compounds 25 and 36 emerged as the most potent MAO-B inhibitors of all the series of synthesized compounds with IC₅₀ values of 0.13 μM and 0.10 μM, respectively. Furthermore, kinetic studies of inhibitor 35 showed mixed inhibition mode. Exploration of structure activity relationship (SAR) revealed the role of functionalities and length of linkers on potency. Acute toxicity evaluation showed the safety of tested compounds up to 2000 mg/kg dose. PAMPA-BBB evaluation showed BBB permeability of the tested compounds, while MTT assay performed on neuroblastoma SHSY5Y cells showed that all the tested compounds are non-neurotoxic in the tested concentrations. Docking studies showed a strong correlation with experimental in vitro results via binding orientations and interaction patterns of the synthesized compounds into the binding sites of target enzymes. We have successfully identified safe, non-neurotoxic, and blood brain barrier permeable multitarget lead compounds for the treatment of AD.

Enhancing Biopharmaceutical Attributes of Khellin by Amorphous Binary Solid Dispersions

Khellin, a furanochromone isolated from fruits and seeds of Ammi visnaga, is traditionally used in many eastern Mediterranean countries. The plant decoction and the crystalline substance khellin have many pharmacological activities. For instance, it acts as a bronchodilator and also relieves renal colic and urethral stones, etc. However, the low water solubility (~ 120 µg/mL) and low bioavailability limit its therapeutic application. Thus, the present research explores the development of its binary and ternary solid dispersion formulations to improve its solubility and dissolution behavior. A 24-well plate miniaturized protocol was established to identify the optimal hydrophilic polymer to prepare its solid dispersions. PEG-4000 was recognized as the favorable hydrophilic carrier in preparation of solid dispersion, SSB17. The formulation displayed ~ five-fold enhancement in the aqueous solubility of khellin. The binary solid dispersion SSB17 was manufactured at a gram scale and evaluated using ¹H-NMR, ¹³C-NMR, FT-IR, p-XRD, SEM, DSC, in vitro dissolution, and predicted pharmacokinetics. The quantitative dissolution data of SSB17 demonstrated ~ 2-3-fold improvement in AUC at physiological pH conditions. These conclusions highlight the basis for further preclinical studies on solid dispersions of khellin with improved biopharmaceutical properties.

Identification of plant-based multitargeted leads for Alzheimer's disease: In-vitro and in-vivo validation of Woodfordia fruticosa (L.) Kurz

BACKGROUND

Alzheimer's disease (AD) is a complex neurodegenerative disease with no availability of disease-modifying therapeutics. The complex etiology and recent failures in clinical trials indicate the need for multitargeted agents.

PURPOSE

The present study aims to discover new plant-based multitargeted anti-AD leads.

METHODS

A library of plant extracts was screened for inhibition of acetylcholinesterase (AChE), butyrylcholinesterase (BChE), and beta-site amyloid precursor protein cleaving enzyme 1 (BACE-1). The secondary metabolites of active extracts were also tested, followed by enzyme-kinetics and molecular modeling to understand the mechanism of inhibition. The most active extract was investigated for in-vivo anti-dementia activity in behavioral mice models.

RESULTS

Among the library of 105 extracts, Woodfordia fruticosa (SBE-80) and Bergenia ciliata (SBE-65) extracts displayed significant inhibition of all three enzymes. Gallic acid, one of the constituents of both plants, shows moderate inhibition of AChE and BACE-1. Catechin-3-O-gallate (CG), another constituent of SBE-65, inhibits EeAChE, rHuAChE, and eqBChE with IC₅₀'s of 29.9, 1.77, and 8.4 µM, respectively; along with a mild-inhibition of BACE-1. Ellagic acid, the constituent of SBE-80, inhibits BACE-1 with an IC₅₀ value of 16 µM. The W. fruticosa extract SBE-80 at the dose of 25 mg/kg QD × 9 (PO) displayed memory-enhancing activity in Morris Water Maze and Passive Avoidance Test in Swiss albino mice. Treatment with SBE-80 also inhibits AChE in-vivo; whereas, a non-significant decrease in the serum TBARS was observed.

CONCLUSION

W. fruticosa is identified for the first time as an anti-AD lead candidate. The in-vitro and in-vivo data presented herein and the documented safety profile of W. fruticosa indicate its strong potential for preclinical development as a botanical drug for dementia/AD.

Non-Alkaloid Cholinesterase Inhibitory Compounds from Natural Sources

Alzheimer's disease (AD) is a severe neurodegenerative disorder of different brain regions accompanied by distresses and affecting more than 25 million people in the world. This progressive brain deterioration affects the central nervous system and has negative impacts on a patient's daily activities such as memory impairment. The most important challenge concerning AD is the development of new drugs for long-term treatment or prevention, with lesser side effects and greater efficiency as cholinesterases inhibitors and the ability to remove amyloid-beta(Aβ) deposits and other related AD neuropathologies. Natural sources provide promising alternatives to synthetic cholinesterase inhibitors and many have been reported for alkaloids while neglecting other classes with potential cholinesterase inhibition. This review summarizes information about the therapeutic potential of small natural molecules from medicinal herbs, belonging to terpenoids, coumarins, and phenolic compounds, and others, which have gained special attention due to their specific modes of action and their advantages of low toxicity and high efficiency in the treatment of AD. Some show superior drug-like features in comparison to synthetic cholinesterase inhibitors. We expect that the listed phytoconstituents in this review will serve as promising tools and chemical scaffolds for the discovery of new potent therapeutic leads for the amelioration and treatment of Alzheimer's disease.

New therapeutics beyond amyloid-β and tau for the treatment of Alzheimer's disease

As the population ages, Alzheimer's disease (AD), the most common neurodegenerative disease in elderly people, will impose social and economic burdens to the world. Currently approved drugs for the treatment of AD including cholinesterase inhibitors (donepezil, rivastigmine, and galantamine) and an N-methyl-D-aspartic acid receptor antagonist (memantine) are symptomatic but poorly affect the progression of the disease. In recent decades, the concept of amyloid-β (Aβ) cascade and tau hyperphosphorylation leading to AD has dominated AD drug development. However, pharmacotherapies targeting Aβ and tau have limited success. It is generally believed that AD is caused by multiple pathological processes resulting from Aβ abnormality, tau phosphorylation, neuroinflammation, neurotransmitter dysregulation, and oxidative stress. In this review we updated the recent development of new therapeutics that regulate neurotransmitters, inflammation, lipid metabolism, autophagy, microbiota, circadian rhythm, and disease-modified genes for AD in preclinical research and clinical trials. It is to emphasize the importance of early diagnosis and multiple-target intervention, which may provide a promising outcome for AD treatment.

Does the application of acetylcholinesterase inhibitors in the treatment of Alzheimer's disease lead to depression?

Introduction: Alzheimer's disease and depression are health conditions affecting millions of people around the world. Both are strongly related to the level of the neurotransmitter acetylcholine. Since cholinergic deficit is characteristic of Alzheimer's disease, acetylcholinesterase inhibitors are applied as relevant drugs for the treatment of this disease, elevating the level of acetylcholine. On the other hand, a high level of acetylcholine is found to be associated with the symptoms of clinical depression.Areas covered: This article aims to discuss if acetylcholinesterase inhibitors used as anti-Alzheimer's drugs could be the cause of the symptoms of clinical depression often linked to this neurological disorder. Emphasis will be put on drugs currently in use and on newly investigated natural products, which can inhibit AChE activity.Expert opinion: Currently, it is not proven that the patient treated for Alzheimer's disease is prone to increased risk for depression due to the acetylcholinesterase inhibition, but there are strong indications. The level of acetylcholine is not the only factor in highly complicated diseases like AD and depression. Still, it needs to be considered isolated, keeping in mind the nature of presently available therapy, especially during a rational drug design process.

Candidate Anti-COVID-19 Medicinal Plants from Ethiopia: A Review of Plants Traditionally Used to Treat Viral Diseases

BACKGROUND

Emerging viral infections are among the major global public health concerns. The pandemic COVID-19 is a contagious respiratory and vascular disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). There are no medicines that can treat SARS-CoV-2 except the vaccines. Therefore, searching for plant-originated therapeutics for the treatment of COVID-19 is required. Consequently, reviewing medicinal plants used to treat different viral infections is mandatory. This review article aims to review the ethnobotanical knowledge of medicinal plants traditionally used to treat different viral diseases by the Ethiopian people and suggests those plants as candidates to fight COVID-19.

METHODS

Articles written in English were searched from online public databases using searching terms like "Traditional Medicine," "Ethnobotanical study," "Active components," "Antiviral activities," and "Ethiopia." Ethnobotanical data were analyzed using the Excel statistical software program.

RESULT

From the 46 articles reviewed, a total of 111 plant species were claimed to treat viral infections. Fifty-six (50.4%) of the plant species had reported to have antiviral active components that are promising to treat COVID-19. Lycorine, gingerol shogaol, resveratrol, rhoifolin, oleanolic acid, kaempferol, rosmarinic acid, almond oil, ursolic acid, hederagenin, nigellidine, α-hederin, apigenin, nobiletin, tangeretin, chalcone, hesperidin, epigallocatechin gallate, allicin, diallyl trisulfide, ajoene, aloenin, artemisinin, glucobrassicin, curcumin, piperine, flavonoids, anthraquinone, hydroxychloroquine, and jensenone were some of them.

CONCLUSION

The Ethiopian traditional knowledge applies a lot of medicinal plants to treat different viral infections. Reports of the chemical components of many of them confirm that they can be promising to fight COVID-19.

Multitarget Biological Profiling of New Naphthoquinone and Anthraquinone-Based Derivatives for the Treatment of Alzheimer's Disease

Two series of naphthoquinone and anthraquinone derivatives decorated with an aromatic/heteroaromatic chain have been synthesized and evaluated as potential promiscuous agents capable of targeting different factors playing a key role in Alzheimer’s disease (AD) pathogenesis. On the basis of the in vitro biological profiling, most of them exhibited a significant ability to inhibit amyloid aggregation, PHF6 tau sequence aggregation, acetylcholinesterase (AChE), and monoamine oxidase (MAO) B. In particular, naphthoquinone 2 resulted as one of the best performing multitarget-directed ligand (MTDL) experiencing a high potency profile in inhibiting β-amyloid (Aβ₄₀) aggregation (IC₅₀ = 3.2 μM), PHF6 tau fragment (91% at 10 μM), AChE enzyme (IC₅₀ = 9.2 μM) jointly with a remarkable inhibitory activity against MAO B (IC₅₀ = 7.7 nM). Molecular modeling studies explained the structure–activity relationship (SAR) around the binding modes of representative compound 2 in complex with hMAO B and hAChE enzymes, revealing inhibitor/protein key contacts and the likely molecular rationale for enzyme selectivity. Compound 2 was also demonstrated to be a strong inhibitor of Aβ₄₂ aggregation, with potency comparable to quercetin. Accordingly, atomic force microscopy (AFM) revealed that the most promising naphthoquinones 2 and 5 and anthraquinones 11 and 12 were able to impair Aβ₄₂ fibrillation, deconstructing the morphologies of its fibrillar aggregates. Moreover, the same compounds exerted a moderate neuroprotective effect against Aβ₄₂ toxicity in primary cultures of cerebellar granule cells. Therefore, our findings demonstrate that these molecules may represent valuable chemotypes toward the development of promising candidates for AD therapy.

Journey on Naphthoquinone and Anthraquinone Derivatives: New Insights in Alzheimer's Disease

Alzheimer's disease (AD) is a progressive neurodegenerative disease that is characterized by memory loss, cognitive impairment, and functional decline leading to dementia and death. AD imposes neuronal death by the intricate interplay of different neurochemical factors, which continue to inspire the medicinal chemist as molecular targets for the development of new agents for the treatment of AD with diverse mechanisms of action, but also depict a more complex AD scenario. Within the wide variety of reported molecules, this review summarizes and offers a global overview of recent advancements on naphthoquinone (NQ) and anthraquinone (AQ) derivatives whose more relevant chemical features and structure-activity relationship studies will be discussed with a view to providing the perspective for the design of viable drugs for the treatment of AD. In particular, cholinesterases (ChEs), β-amyloid (Aβ) and tau proteins have been identified as key targets of these classes of compounds, where the NQ or AQ scaffold may contribute to the biological effect against AD as main unit or significant substructure. The multitarget directed ligand (MTDL) strategy will be described, as a chance for these molecules to exhibit significant potential on the road to therapeutics for AD.

Natural Compounds for the Prevention and Treatment of Cardiovascular and Neurodegenerative Diseases

Secondary metabolites from plants and fungi are stimulating growing interest in consumers and, consequently, in the food and supplement industries. The beneficial effects of these natural compounds are being thoroughly studied and there are frequent updates about the biological activities of old and new molecules isolated from plants and fungi. In this article, we present a review of the most recent literature regarding the recent discovery of secondary metabolites through isolation and structural elucidation, as well as the in vitro and/or in vivo evaluation of their biological effects. In particular, the possibility of using these bioactive molecules in the prevention and/or treatment of widely spread pathologies such as cardiovascular and neurodegenerative diseases is discussed.

Identification of aplysinopsin as a blood-brain barrier permeable scaffold for anti-cholinesterase and anti-BACE-1 activity

Aplysinopsins are a group of marine-derived indole alkaloids that display diverse array of pharmacological effects. However, their effect on anti-Alzheimer targets has not been reported. Herein, we report the synthesis of aplysinopsin (1) and its effect on cholinesterases and beta-site amyloid-precursor protein cleaving enzyme 1 (BACE-1). It inhibits electric eel acetylcholinesterase (AChE), equine serum butyrylcholinesterase (BChE), and human BACE-1 with IC₅₀ values of 33.9, 30.3, and 33.7 µM, respectively, and excellent BBB permeability (P_e 8.92 × 10^-6 cm/s). To optimize its sub-micromolar activity, the first-generation analogs were prepared and screened. Two most active analogs 5b and (Z)-8g were found to effectively permeate the BBB (P_e > 5 × 10^-6 cm/s). The N-sulphonamide derivative 5b display better cholinesterase inhibition, whereas the other analog (Z)-8g strongly inhibits BACE-1 (IC₅₀ 0.78 µM) activity. The analog 5b interacts primarily with PAS of AChE, and thus exhibit a mixed-type of inhibition. In addition, aplysinopsin along with new analogs inhibited the self-induced Aβ_1-42 aggregation. The data presented herein indicate that the aplysinopsin-scaffold holds a potential for further investigation as a multi-targeted anti-Alzheimer agent.

Fungal Pigments and Their Roles Associated with Human Health

Fungi can produce myriad secondary metabolites, including pigments. Some of these pigments play a positive role in human welfare while others are detrimental. This paper reviews the types and biosynthesis of fungal pigments, their relevance to human health, including their interactions with host immunity, and recent progresses in their structure-activity relationships. Fungal pigments are grouped into carotenoids, melanin, polyketides, and azaphilones, etc. These pigments are phylogenetically broadly distributed. While the biosynthetic pathways for some fungal pigments are known, the majority remain to be elucidated. Understanding the genes and metabolic pathways involved in fungal pigment synthesis is essential to genetically manipulate the production of both the types and quantities of specific pigments. A variety of fungal pigments have shown wide-spectrum biological activities, including promising pharmacophores/lead molecules to be developed into health-promoting drugs to treat cancers, cardiovascular disorders, infectious diseases, Alzheimer's diseases, and so on. In addition, the mechanistic elucidation of the interaction of fungal pigments with the host immune system provides valuable clues for fighting fungal infections. The great potential of fungal pigments have opened the avenues for academia and industries ranging from fundamental biology to pharmaceutical development, shedding light on our endeavors for disease prevention and treatment.

In vivo Hepatoprotective and in vitro Radical Scavenging Activities of Extracts of Rumex abyssinicus Jacq. Rhizome

BACKGROUND

Liver diseases contribute a prominent global burden of mortality and morbidity. The current therapies of liver diseases have numerous limitations including severe adverse effects. This denotes that new more effective, safer, and cheaper drugs are required and medicinal plants used in traditional medicines often offer ideal opportunities. Accordingly, the present study aimed to evaluate the in vivo hepatoprotective and in vitro radical scavenging activities of dried rhizome extracts of Rumex abyssinicus (R. abyssinicus), which is traditionally claimed to provide hepatoprotection.

MATERIALS AND METHODS

Hepatoprotective activity of extracts was evaluated using carbon tetrachloride (CCl4)-induced liver injury in mice. Pre- and post-treatment models were employed to test the effect of the extracts and silymarin (standard drug). Serum biochemical markers and liver histopathology were used as parameters to evaluate hepatoprotective activities whereas in vitro radical scavenging activity was tested by 2, 2-diphenyl-2-picrylhydrazyl hydrate (DPPH) assay.

RESULTS AND CONCLUSION

Oral administration of CCl4 (1 ml/kg) significantly (P<0.001) raised the serum levels of liver enzyme markers compared to the normal control group. Pre-treatment with 125, 250, and 500 mg/kg of R. abyssinicus extract reduced the serum level of CCl4-induced rise in liver enzyme markers with the highest reduction observed at a dose of 500 mg/kg. Likewise, in the post-treatment model, the crude extract and butanol fraction at dose 500 mg/kg reduced levels of liver enzymes. Histopathological examinations revealed lesser liver damage of extract-treated mice compared to the toxic (CCl4-treated) controls. The in vitro radical scavenging activity of the different extracts showed concentration-dependent radical scavenging activity. Thus, the results of this study may justify the traditional use of the plant as a hepatoprotective agent.

CONCLUSION

Results of serum biochemical markers and histopathological examinations of CCl4-induced mice models, in the present study, show the hepatoprotective potential of extracts from the rhizome of R. abyssinicus.