Anticholinesterase Activity of Eight Medicinal Plant Species: In Vitro and in Silico Studies in the Search for Therapeutic Agents against Alzheimer's Disease

Many Bangladeshi medicinal plants have been used to treat Alzheimer's disease and other neurodegenerative diseases. In the present study, the anticholinesterase effects of eight selected Bangladeshi medicinal plant species were investigated. Species were selected based on the traditional uses against CNS-related diseases. Extracts were prepared using a gentle cold extraction method. In vitro cholinesterase inhibitory effects were measured by Ellman's method in 96-well microplates. Blumea lacera (Compositae) and Cyclea barbata (Menispermaceae) were found to have the highest acetylcholinesterase inhibitory (IC50, 150 11 and 176 14 g/mL, respectively) and butyrylcholinesterase inhibitory effect (IC50, 297 13 and 124 2 g/mL, respectively). Cyclea barbata demonstrated competitive inhibition, where Blumea lacera showed an uncompetitive inhibition mode for acetylcholinesterase. Smilax guianensis (Smilacaceae) and Byttneria pilosa (Malvaceae) were also found to show moderate AChE inhibition (IC50, 205 31 and 221 2 g/mL, respectively), although no significant BChE inhibitory effect was observed for extracts from these plant species. Among others, Thunbergia grandiflora (Acanthaceae) and Mikania micrantha (Compositae) were found to display noticeable AChE (IC50, 252 22 g/mL) and BChE (IC50, 314 15 g/mL) inhibitory effects, respectively. Molecular docking experiment suggested that compounds 5-hydroxy-3,6,7,3,4-pentamethoxyflavone (BL4) and kaempferol-3-O-α-L-rhamnopyranosyl-(1LongRightArrow6)-β-D-glucopyranoside (BL5) from Blumea lacera bound stably to the binding groove of the AChE and BChE by hydrogen-bond interactions, respectively. Therefore, these compounds could be candidates for cholinesterase inhibitors. The present findings demonstrated that Blumea lacera and Cyclea barbata are interesting objects for further studies aiming at future therapeutics for Alzheimer's disease

Antidiarrheal activity of ethanolic bark extract of Mitragyna diversifolia

The ethanolic bark extract of Mitragyna diversifolia showed significant (p<0.05) antidiarrheal activity on gastrointestinal motility with barium sulfate milk model and castor oil- induced diarrheal model in rats. These results revealed that the bark extract possess pharmacological activity against diarrhea and may possibly explain the use of the plant in traditional medicine

Neuropharmacological and antiproliferative activity of Tetrastigma leucostaphyllum (Dennst.) Alston: Evidence from in-vivo, in-vitro and in-silico approaches

As the incidence of neurodegeneration and cancer fatalities remains high, researchers are focusing their efforts on discovering and developing effective medications, especially plant-based drugs, against these diseases. Hence, this research aimed to investigate the neuropharmacological potentials of aerial parts of Tetrastigma leucostaphyllum, employing some behavioral models, while the antiproliferative effect was explored against a panel of cancer cell lines (MGC-803, A549, U-251, HeLa and MCF-7) using a colorimetric assay. In addition, active extracts were analyzed by GC–MS technique to identify the active compounds, where some selective compounds were docked with the particular pure proteins to check their binding affinity. Results from neuropharmacological research indicated that the total extract and its fractions may be effective (p = 0.05, 0.01, and 0.001, respectively) at doses of 100, 200, and 400 mg/kg of animal body weight. The greatest antidepressant and anxiolytic effects were found in the n-hexane fraction. The n-haxane fraction also exhibited the highest cytotoxicity against the U-251 cell line (IC5014.3 μg/mL), followed by the A549, MG-803, HeLa, and MCF-7 cell lines, respectively. From the n-hexane fraction, ten chemicals were detected using the GC–MS method. Additionally, the in-silico research revealed interactions between the n-hexane fractions' identified compounds and the antidepressant, anxiolytic, and cytotoxic receptors. The molecules showed binding affinities that ranged from 4.6 kcal/mol to 6.8 kcal/mol, which indicates the likelihood that they would make good drug candidates. This study highlighted the plant's neuropharmacological and cytotoxic properties, however, more research is needed to determine the etymological origin of these effects

Evaluation of Various Solvent Extracts of Tetrastigma leucostaphylum (Dennst.) Alston Leaves, a Bangladeshi Traditional Medicine Used for the Treatment of Diarrhea

Tetrastigma leucostaphylum (TL) is an important ethnic medicine of Bangladesh used to treat diarrhea and dysentery. Hence, current study has been designed to characterize the antidiarrheal (in vivo) and cytotoxic (in vitro) effects of T. leucostaphylum. A crude extract was prepared with methanol (MTL) and further partitioned into n-hexane (NTL), dichloromethane (DTL), and n-butanol (BTL) fractions. Antidiarrheal activity was investigated using castor oil induced diarrhea, enteropooling, and gastrointestinal transit models, while cytotoxicity was evaluated using the brine shrimp lethality bioassay. In antidiarrheal experiments, all doses (100, 200, and 400 mg/kg) of the DTL extract significantly reduced diarrheal stool frequency, volume and weight of intestinal contents, and gastrointestinal motility in mice. Similarly, in the cytotoxicity assay, all extracts exhibited activity, with the DTL extract the most potent (LC50 67.23 &mu;g/mL). GC-MS analysis of the DTL extract identified 10 compounds, which showed good binding affinity toward M3 muscarinic acetylcholine, 5-HT3, Gut inhibitory phosphodiesterase, DNA polymerase III subunit alpha, and UDP-N-acetylglucosamine-1 carboxyvinyltransferase enzyme targets upon molecular docking analysis. Although ADME/T analyses predicted the drug-likeness and likely safety upon consumption of these bioactive compounds, significant toxicity concerns are evident due to the presence of the known phytotoxin, 2,4-di-tert-butylphenol. In summary, T. leucostaphylum showed promising activity, helping to rationalize the ethnomedicinal use and importance of this plant, its safety profile following both acute and chronic exposure warrants further investigation

Evaluation of anti-nociceptive and anti-inflammatory activities of the methanol extract of Holigarna caustica (Dennst.) Oken leaves

Ethnopharmacological relevance: Holigarna caustica (Dennst.) is commonly used in traditional medicine to treat a variety of painful conditions such as eye irritation, inflammation, arthritis, skin diseases, cuts and wounds.Aim of the study: The present study was undertaken to investigate the anti-nociceptive and anti-inflammatory activities of the methanol extract of H. caustica leaves and to elucidate its possible mechanism(s) of action.Materials and methods: Fresh leaves of H. caustica were collected, dried, and extracted with methanol (MEHC). MEHC was subjected to activity testing, using chemical-induced (acetic acid and formalin test) and heat-induced (hot plate and tail immersion test) pain models. To determine the possible mechanism behind the anti-nociceptive activity of MEHC, the opioid antagonist naltrexone was used to evaluate the involvement of opioid receptors in the case of formalin, hot plate and tail immersion tests, while the involvement of the cGMP and ATP-sensitive K+ channel pathways were assessed using methylene blue and glibenclamide respectively, in the acetic acid-induced writhing test. In parallel, the carrageenan-induced paw oedema model was used to determine the anti-inflammatory potential of the extract. Exploratory and motor behaviours were evaluated by the open-field test. Various bioactive compounds potentially responsible for the anti-nociceptive and anti-inflammatory activities were ascertained using GC-MS analysis.Results: MEHC showed strong, significant and dose-dependent anti-nociceptive activity in all chemical-induced and heat-induced pain models at all experimental doses. The association of opioid receptors with the observed anti-nociceptive effects was confirmed by using naltrexone. The cGMP and ATP-sensitive K+ channel pathway was also shown to be involved in the anti-nociceptive activity of MEHC. In addition, MEHC exhibited a dose-dependent inhibition of inflammatory oedema induced by carrageenan. MEHC was not connected with changes in either the locomotor activity or motor responses of mice. In a GC-MS analysis, 40 compounds were identified, among which twelve are documented bioactive compounds with potent analgesic and anti-inflammatory properties.Conclusions: Our current study revealed that MEHC possesses strong central and peripheral anti-nociceptive as well as anti-inflammatory activity. It may also be concluded that both opioid receptors as well as the cGMP and ATP-sensitive K+ channel pathway are involved in the anti-nociceptive mechanism of MEHC. This study rationalizes the ethnomedicinal use of H. caustica leaves in various painful conditions.</p

Investigation of the Biological Activities and Characterization of Bioactive Constituents of <i>Ophiorrhiza rugosa</i> var. <i>prostrata</i> (D.Don) &amp; Mondal Leaves through In Vivo, In Vitro, and In Silico Approaches

Ophiorrhiza rugosa var. prostrata is one of the most frequently used ethnomedicinal plants by the indigenous communities of Bangladesh. This study was designed to investigate the antidiarrheal, anti-inflammatory, anthelmintic and antibacterial activities of the ethanol extract of O. rugosa leaves (EEOR). The leaves were extracted with ethanol and subjected to in vivo antidiarrheal screening using the castor oil-induced diarrhea, enteropooling, and gastrointestinal transit models. Anti-inflammatory efficacy was evaluated using the histamine-induced paw edema test. In parallel, in vitro anthelmintic and antibacterial activities were evaluated using the aquatic worm and disc diffusion assays respectively. In all three diarrheal models, EEOR (100, 200 and 400 mg/kg) showed obvious inhibition of diarrheal stool frequency, reduction of the volume and weight of the intestinal contents, and significant inhibition of intestinal motility. Also, EEOR manifested dose-dependent anti-inflammatory activity. Anthelmintic action was deemed significant (P &lt; 0.001) with respect to the onset of paralysis and helminth death. EEOR also resulted in strong zones of inhibition when tested against both Gram-positive and Gram-negative bacteria. GC-MS analysis identified 30 compounds within EEOR, and of these, 13 compounds documented as bioactive showed good binding affinities to M3 muscarinic acetylcholine, 5-HT3, tubulin and GlcN-6-P synthase protein targets in molecular docking experiments. Additionally, ADME/T and PASS analyses revealed their drug-likeness, likely safety upon consumption and possible pharmacological activities. In conclusion, our findings scientifically support the ethnomedicinal use and value of this plant, which may provide a potential source for future development of medicines