Enzyme inhibition activities of the extracts from rhizomes ofGloriosa superbaLinn (Colchicaceae)

Lipoxygenase inhibitory synthetic derivatives of methyl gallate regulate gene expressions of COX-2 and cytokines to reduce animal model arthritis

Mammalian lipoxygenases (LOXs) are involved in the biosynthesis of mediators of anaphylactic reactions and have been implicated in cell maturation, the pathogenesis of bronchial asthma, atherosclerosis, rheumatoid arthritis, cardiovascular diseases, Alzheimer's disease and osteoporosis. Hence LOX inhibition in chronic conditions can lead to reducing the disease progression, which can be a good target for treating these diseases. The present study deals with designing methyl gallate derivatives and their anti-inflammatory effect by in silico, in vitro and in vivo methods. Designed derivatives were docked against LOX enzyme, and molecular dynamic simulations were carried out. Following the synthesis of derivatives, in vitro LOX inhibition assay, enzyme kinetics and fluorescence quenching studies were performed. One of the derivatives of methyl gallate (MGSD 1) was demonstrated as an anti-inflammatory agent for the treatment of rheumatoid arthritis in the animal model. Amelioration of Freund's complete adjuvant (FCA)-induced arthritis by methyl gallate and its derivative with a concentration of 10-40 mg.kg-1 has been assessed in vivo in a 28-day-long study. TNF-α and COX-2 gene expression were also studied. Methyl gallate synthetic derivatives (MGSDs) inhibited LOX with an IC50 of 100 nM, 304 nM, and 226 nM for MGSD 1, MGSD 2, and MGSD 3, respectively. Fluorescence quenching methods also prove their binding characteristics, and 200 ns simulations studies showed that the RMSDs for the entire complex were less than 2.8 Å. The in vivo results showed that methyl gallate was required approximately five times diclofenac for the same level of effect, and the synthesised (MGSD 1) compound required only approximately 1/12 of diclofenac for the same level of effect in in-vivo studies. The preeminent expression of COX-2 and TNF-α genes was significantly decreased after the treatment of the methyl gallate derivative. Hence, the in vivo results showed that the referenced synthetic derivative might have more arthritis-reducing properties than the parent compound methyl gallate and is more potent than the standard drug diclofenac, with no apparent induced toxicity.

Mineral Profile, Antioxidant, Anti-Inflammatory, Antibacterial, Anti-Urease and Anti-α-Amylase Activities of the Unripe Fruit Extracts of Pistacia atlantica

Pistacia Atlantica in folk medicine is used by Algerian traditional healers for treating a wide variety of diseases and conditions including dyspepsia, digestive problems, peptic ulcers, and, in particular, inflammatory diseases. The present study aimed to assess the phytochemical composition, in vitro antioxidant activity (using 2,2-diphenyl-1-picrylhydrazyl (DPPH), ABTS+, and reducing power methods), enzyme inhibitory activity (towards α-amylase and urease), antibacterial activity, and in vivo anti-inflammatory activity of the unripe fruit extracts of Pistacia atlantica collected from different parts of the Djelfa region of Algeria. According to the findings, various aqueous extracts exhibited significant antioxidant and enzymatic activities in all tests, but showed that they have a weak inhibitory effect against all tested bacterial strains. Twenty-one minerals comprising both macro- and microelements (Ba, Br, Ca, Cl, Co, Cr, Cs, Eu, Fe, K, Mg, Mn, Mo, Na, Rb, Sb, Sc, Sr, Th, U, and Zn) were determined using the technique of neutron activation analysis (INAA). The result indicates that the concentration of the mineral element is close to the minimal FAO recommendation. In addition, the result revealed significant anti-inflammatory activities. The data generated can be a valuable source of information for the pharmaceutical industry and medical research. These results suggest that the unripe fruit extracts of Pistacia atlantica have an appropriate potential to be utilized across a wide range of contexts as an agent with multifunctional uses, as well as a natural remedy for other physiological diseases.

Antiproliferative Potential of Gloriosine: A Lead for Anticancer Drug Development

Gloriosine, a colchicine-like natural product, is widely obtained from Gloriosa superba roots. Despite having remarkable anticancer potential, colchicine could not pave its way to the clinic, while gloriosine is yet to be investigated for its pharmacological effects. In the present work, 14 compounds, including gloriosine, were isolated from the G. superba roots and were characterized by NMR spectroscopy. Gloriosine (11) was evaluated for its antiproliferative activity against a panel of 15 human cancer cell lines of different tissues and normal breast cells. Gloroisine (11) displayed significant antiproliferative activity against various cancer cell lines selectively, with IC₅₀ values ranging from 32.61 to 100.28 nM. Further, gloriosine (11) was investigated for its apoptosis-inducing ability and found to form apoptotic bodies. It also inhibited A549 cell migration in the wound healing assay. Finally, molecular docking studies were performed to explore the possible binding modes of gloriosine with the colchicine-binding site of tubulin protein. Our findings suggested that gloriosine might be a potential lead for anticancer drug discovery.

Inhibitory potential of nitrogen, oxygen and sulfur containing heterocyclic scaffolds against acetylcholinesterase and butyrylcholinesterase

Heterocycles are the key structures in organic chemistry owing to their immense applications in the biological, chemical, and pharmaceutical fields. Heterocyclic compounds perform various noteworthy functions in nature, medication, innovation etc. Most frequently, pure nitrogen heterocycles or various positional combinations of nitrogen, oxygen, and sulfur atoms in five or six-membered rings can be found. Inhibition of acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) enzymes is a popular strategy for the management of numerous mental diseases. In this context, cholinesterase inhibitors are utilized to relieve the symptoms of neurological illnesses like dementia and Alzheimer's disease (AD). The present review focuses on various heterocyclic scaffolds and their role in designing and developing new potential AChE and BChE inhibitors to treat AD. Moreover, a detailed structure-activity relationship (SAR) has been established for the future discovery of novel drugs for the treatment of AD. Most of the heterocyclic motifs have been used in the design of new potent cholinesterase inhibitors. In this regard, this review is an endeavor to summarize the biological and chemical studies over the past decade (2010-2022) describing the pursuit of new N, O and S containing heterocycles which can offer a rich supply of promising AChE and BChE inhibitory activities.

Anti-cancer activities of Schedule E1 drugs used in ayurvedic formulations

Schedule E1 is an important part of Drugs and Cosmetics Act (Government of India) that comprises the list of poisonous drugs from plant, animal and mineral origins to be consumed under medical supervision. Ayurveda, the world's oldest medicinal system has a list of drugs represented in schedule E1 that are used since thousands of years. This review reports the anti-cancer activities of fifteen toxic ayurvedic drugs from plant origin represented in Drugs and Cosmetics Act, 1940. The information was collected from the various authentic sources, compiled and summarised. The plant extracts, formulations, phytoconstituents and other preparations of these drugs have shown effective activities against mammary carcinoma, neuroblastoma, non-small cell lung carcinoma, lymphocytic leukaemia, colorectal adenocarcinoma, Ehrlich ascites carcinoma, prostate adenocarcinoma, glioblastoma asterocytoma and other malignancies. They have various mechanisms of action including Bax upregulation, Bcl2 downregulation, induction of cell cycle arrest at S phase, G2/M phase, inhibition of vascular endothelial growth factors, inhibition of Akt/mTOR signalling etc. Certain traditional ayurvedic preparations containing these plants are reported beneficial and the possibilities of these drugs as the alternative and adjuvant therapeutic agents in the current cancer care have been discussed. The studies suggest that these drugs could be utilised in future for the critical care of malignancies.

An evidence based efficacy and safety assessment of the ethnobiologicals against poisonous and non-poisonous bites used by the tribals of three westernmost districts of West Bengal, India: Anti-phospholipase A2 and genotoxic effects

Introduction

To explore the ethnobiological wisdom of the tribals of three western districts of West Bengal, India against poisonous and non-poisonous bites and stings, a quantitative approach was adopted. These age-old yet unexplored knowledge can be utilized in finding lead-molecules against poisonous and non-poisonous animal-bites. Further, an evidence-based approach is needed to assess the venom-neutralization ability of plants by experimental studies.

Materials and methods

During 2008–2009 and 2012–2017, 11 ethnomedicinal surveys were carried out to explore the use of medicinal flora and fauna via conducting open semi-structured interviews with 47 traditional healers (THs) or informants. The retrieved dataset was statistically evaluated using seven quantitative-indexes: use-value (UV), informants'-consensus-factor (ICF), fidelity-level (FL), relative-importance (RI), cultural importance-index (CI), index of agreement on remedies (IAR) and cultural agreement-index (CAI). Anti-phospholipaseA₂ (PLA₂) properties of selected plant extracts were also examined. In addition, the cytotoxicity and genotoxicity of the water extract of the plants showing high FL as well as significant PLA₂ inhibitory potential were investigated using Allium cepa root tip assay.

Results

A total of 41 traditional-formulations (TFs) containing 40 plant species (of 39 genera from 28 families) and 3 animal species were prescribed by the THs. Fabaceae exhibited most number of medicinal plants. Piper nigrum (1.78) and Apis cerana indica and Crossopriza lyoni (both 0.21) exhibited the highest UV among the plants and the animals respectively. Stinging of centipede and dog/cat/hyena bite displayed highest ICF (1.00 each). Among the plants, the maximum RI (0.91) and CI (4.98) values were observed for Aristolochia indica. IAR (1.00) was recorded maximum for Achyranthes aspera, Gloriosa superba, Lycopodium cernuum, Smilax zeylanica and Streblus asper. Maximum CAI value was noted for Piper nigrum (5.5096). Among the animals, Apis cerana indica (0.31) and Crossopriza lyoni (1.52) displayed the highest RI and CI values respectively. Crossopriza lyoni (0.99) and Apis cerana indica (1.3871) exhibited maximum IAR and CAI values respectively. Plants showing higher FL exhibited higher anti-PLA₂ activity via selective inhibition of human-group PLA₂. In addition, Allium cepa root tip assay has indicated the safety and/or toxicity of the plant parts prescribed by the THs. Root water extracts of Aristolochia indica and Gloriosa superba exhibited significant genotoxicity and cytotoxicity.

Conclusions

Three western districts of West Bengal is the natural abode for many tribal and non-tribal communities. A noteworthy correlation was established between the plants used against poisonous-bites and their anti-PLA₂ activity. A few plant parts used by the THs also exhibited high toxicity. Such alternative medical practices serve as the only option in these underprivileged and backward areas during medical-exigencies.

Exploitation of apple pomace towards extraction of triterpenic acids, antioxidant potential, cytotoxic effects, and inhibition of clinically important enzymes

Apple pomace (AP) utilised for analysis of triterpenic acids (TTAs) using HPLC-MS/MS. The methanol, ethanol and ethyl acetate extracts showed high phenolic content with significant antioxidant activity compared to chloroform and n-hexane. AP TTAs; ursolic acid, betulinic acid and maslinic acid showed potent antioxidant and enzyme inhibitory effects. The IC₅₀ values were 13.2-30.8 μg/mL (tyrosinase), 19.6-42.5 μg/mL (xanthine oxidase) and 16.6-38.6 μg/mL (urease) for AP extracts and 8.4-25.8 μg/mL (tyrosinase), 12.6-30.2 μg/mL (xanthine oxidase) and 10.1-28.6 μg/mL (urease) for TTAs, compared to the positive controls; kojic acid (10.4 ± 0.06 μg/mL), allopurinol (9.6 ± 0.04 μg/mL) and thiourea (8.9 ± 0.02 μg/mL) towards respective enzymes. UA showed a competitive type of inhibition for tyrosinase, while BA showed a noncompetitive type of inhibition towards xanthine oxidase. In addition, the AP extracts and TTAs exerted significant cytotoxic effects towards the proliferation of cancer cell lines. AP methanol extract (IC₅₀ of 38.5 ± 4.1, 47.1 ± 3.5, 70.6 ± 2.3, and 50.5 ± 3.9 μg/mL) and ursolic acid (IC₅₀ of 6.5 ± 0.7, 15.5 ± 1.4, 20.8 ± 1.3, and 5.6 ± 0.8 μg/mL) showed prominent anticancer activity on Hela, Skov-3, Caski, and NCL cancer cell lines, respectively. Thus, this study shows that the AP & TTAs could be utilized for functional food development and as a potent antioxidant, anticancer, skin whitening, and anti-urolithic agents.

Flavonoids as acetylcholinesterase inhibitors: Current therapeutic standing and future prospects

BACKGROUND

Acetylcholinesterase (AChE), a serine hydrolase, is primarily responsible for the termination of signal transmission in the cholinergic system, owing to its outstanding hydrolyzing potential. Its substrate acetylcholine (ACh), is a neurotransmitter of the cholinergic system, with a predominant effect on motor neurons involved in memory formation. So, by decreasing the activity of this enzyme by employment of specific inhibitors, a number of motor neuron disorders such as myasthenia gravis, glaucoma, Lewy body dementia, and Alzheimer's disease, among others, can be treated. However, the current-available AChE inhibitors have several limitations in terms of efficacy, therapeutic range, and safety.

SCOPE AND APPROACH

Primarily due to the non-compliance of current therapies, new, effective and safe inhibitors are being searched for, especially those which act through multiple receptor sites, but do not elicit undesirable effects. In this regard, the evaluation of phytochemicals such as flavonoids, can be a rational approach. The therapeutic potential of flavonoids has already been recognized agaisnt several ailments. This review deals with various plant-derived flavonoids, their preclinical potential as AChE inhibitors, in established assays, possible mechanisms of action, and structural activity relationship (SAR).

RESULTS AND CONCLUSIONS

Subsequently, a number of plant-derived flavonoids with outstanding efficacy and potency as AChE inhibitors, the mechanistic, their safety profiles, and pharmacokinetic attributes have been discussed. Through derivatization of these reported flavonoids, some limitation in efficacy or pharmacokinetic parameters can be addressed. The selected flavonoids ought to be tested in clinical studies to discover new neuro-therapeutic candidates.

NMR, Novel Pharmacological and In Silico Docking Studies of Oxyacanthine and Tetrandrine: Bisbenzylisoquinoline Alkaloids Isolated from Berberis glaucocarpa Roots

Urease enzyme is responsible for gastric cancer, peptic ulcer, hepatic coma, and urinary stones in millions of people across the world. So, there is a strong need to develop new and safe antiurease drugs, particularly from natural sources. In search for new and effective drugs from natural sources bioassay-guided fractionation and isolation of Berberis glaucocarpa Stapf roots bark resulted in the isolation and characterization, on the basis of 1D and 2D NMR data, of two bisbenzylisoquinoline alkaloids, oxyacanthine (1) and tetrandrine (2), followed by urease inhibition studies. Crude extract, all the subfractions and the isolated compounds 1 and 2 displayed excellent urease enzyme inhibition properties in vitro. The antiurease nature and possible mode of action for compounds 1 and 2 were verified and explained through their molecular docking studies against jack-bean urease enzyme. Half-maximum inhibitory concentration (IC₅₀) was calculated for compounds 1 and 2. The IC₅₀ value was found to be 6.35 and 5.51 µg/mL for compounds 1 and 2, respectively. Both compounds 1 and 2 have minimal cytotoxicity against THP-1 monocytic cells.

Therapeutic potential of songorine, a diterpenoid alkaloid of the genus Aconitum

Alkaloids are well-studied secondary metabolites, with recent preclinical studies evidencing that many of them exhibit anti-cancer, anti-depressant, anti-nociceptive, anti-inflammatory, anti-pyretic, anti-platelet, anti-oxidant, and anti-bacterial properties. Aconitum is a genus rich of diverse alkaloids. More than 450 alkaloids have been identified in a variety of species. Songorine is a C₂₀ diterpenoid alkaloid and 12-keto analog of napelline, isolated from Aconitum soongaricum and was associated with a heterogeneous panel of biological functions. However, the bioactivity profile of this natural product has not been reviewed up to now. The present manuscript aims to summarize the most important biological activities associated with songorine administration in preclinical models. The most significant data found in the scientific literature were evaluated in order to summarize the potential clinical utility of songorine in a diverse spectrum of pathologies and conditions. Songorine and its derivatives have many pharmacological effects including anti-arrhythmic, anti-cardiac-fibrillation, excitation of synaptic transmission, anxiolytic effects, anti-nociceptive, anti-inflammatory, anti-arthritis effects, and a regenerative effect in a skin excision wound animal model. Despite its outstanding pharmacotherapeutic potential, songorine has never been tested in clinical trials. Therefore, further evaluation is required to better evaluate its clinical utility.

Antimicrobial and antioxidant activities of a new metabolite from Quercus incana

Phytochemical investigations of Quercus incana led to the isolation of a new catechin derivative quercuschin (1), along with six known compounds: quercetin (2), methyl gallate (3), gallic acid (4), betulinic acid (5), (Z)-9-octadecenoic acid methyl ester (6) and β-sitosterol glucoside (7) from the ethyl acetate fraction of methanolic extract of the bark. Compound 1 was screened for its antibacterial, antifungal and antioxidant potential. Antibacterial and antifungal activities of the compound were tested against different bacterial and fungal strains, employing the agar well diffusion methods. The antibacterial activity was the highest against Streptococcus pyogenes with 80.0% inhibition, while the antifungal activity of the compound was the highest against Candida glabrata with 80.5% inhibition. The results of the antioxidant activity indicated that the compound exhibited antioxidant activity comparable to that of standard, butylated hydroxyanisole (51.2 μg/10 μl versus 45.9 μg/10 μl).

Antiulcer Effect of Extract/Fractions of Eruca sativa: Attenuation of Urease Activity

Eruca sativa (Rocket salad) is known for its antiulcer properties in the traditional system of treatment. The present study was, therefore, designed to scrutinize its effect on urease activity in vitro. The results demonstrated marked attenuation of urease by the crude extract of various test concentrations with IC₅₀ value of 7.77 mg/mL. On fractionation, marked change in inhibitory profile was observed. The ethyl acetate fraction was the most potent urease inhibitor with IC₅₀ value of 4.17 mg/mL followed by the aqueous fraction with an IC₅₀ value of 5.83 mg/mL. However, hexane did not show significant urease inhibition. In conclusion, the present study illustrated strong antagonism of urease activity and thus validated scientifically the traditional use of the plant in the treatment of ulcers.

Urease Inhibitory Activity of Aerial Parts of Artemisia scoparia: Exploration in an In Vitro Study

Artimisia scoparia has been used in the treatment of different disorders including ulcers. The current study was therefore designed to investigate the aerial parts of  Artemisia scoparia (crude extract, total sterol and flavonoidal contents, and aqueous fraction) for its urease inhibitory potential. The crude of the plant evoked marked attenuation on urease activity, when tested in various concentrations with IC50 values of 4.06 mg/ml. The inhibitory potential was further augmented in the aqueous fraction (IC50: 2.30 mg/ml) of the plant. When the total sterol and flavonoidal contents were challenged against urease, both showed concentration dependent activity; the latter showed maximum potency with IC50 values of 8.04 and 2.10 mg/ml, respectively. In short, the aerial parts of the plant demonstrated marked antagonism on urease and thus our study validated the traditional use of Artemisia scoparia in the treatment of ulcer.

Attenuation of erythrocytic actylcholinesterase by antidepressants

The current study was aimed to scrutinize acetylcholinesterase (AchE) inhibitory profile of two antidepressants, diazepam and phenobarbitone. The experimental designed was based on Michaelis–Menten parameters (apparent Michaelis constant (aKm) and apparent maximum velocity (aVm)) that estimate inhibition (%) as well as the type of inhibition (mechanism). The results showed marked inhibition of AchE by diazepam and the values of aKm and aVm were 65.5% and 52.63%, respectively. These values suggested a competitive type of antagonism for diazepam. Similar trend of antagonism was shown by phenobarbitone when it was subjected to the challenge of AchE with aKm and aVm values of 51.99% and 71.80%, respectively. It is concluded that diazepam and phenobarbitone exhibited prominent AchE attenuation apart from their well-established antidepressant activity, which could be more useful in related diseased conditions.

Lipoxygenase and urease inhibition of the aerial parts of the Polygonatum verticillatum

Over expression of lipoxygenase (LOX) and urease has already contributed to the pathology of different human disease. Targeting the inhibition of these enzymes has proved great clinical utility. The aim of the present study was to scrutinised the inhibitory profile of the aerial parts of the Polygonatum verticillatum enzyme against LOX, urease, acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) using standard experimental protocols. When checked against lipoxygenase, the extracts revealed significant attenuation. Of the tested extracts, the ethyl acetate fraction was the most potent (half-maximal inhibitory concentration (IC(50)): 97 µg/mL) followed by aqueous fraction IC(50): 109 µg/mL). Regarding urease inhibition, n-butanol was the most potent fraction (IC(50): 97 µg/mL). However, the extracts did not show significant inhibition on AChE and BChE. In the preliminary phytochemical tests, the aerial parts of the plant showed the presence of saponins, alkaloids, flavonoids, phenols, tannins and terpenoids. The current findings could be attributed to these groups of compounds.

Bronchodilator activity of aerial parts of Polygonatum verticillatum augmented by anti-inflammatory activity: attenuation of Ca²⁺ channels and lipoxygenase

Polygonatum verticillatum is commonly used for the treatment of asthma and inflammation. The current study was aimed to scrutinize the pharmacological profile of methanolic extract of the aerial parts (PA). Isolated tracheal preparations were used for the evaluation of bronchodilatory activity, whilst the in vivo carrageenan-induced paw oedema test and an in vitro lipoxygenase (LOX) inhibitory assay were used for the assessment of the anti-inflammatory profile of PA. When tested against carbachol and K⁺ (80 mM)-induced contractions, PA caused complete inhibition of isolated rabbit tracheal preparations in a dose-dependent mode, similar to verapamil. While elucidating possible mechanism, PA shifted the Ca²⁺ concentration-response curves to the right, analogous to that produced by verapamil, confirming a Ca²⁺ channel blocker-like activity. PA provoked profound reduction in paw oedema with a maximum protection of 60.87% at 200 mg/kg i.p. in a dose-dependent manner which was augmented by its prominent LOX inhibitory activity (IC₅₀ : 125 µg/mL). These findings authenticated its therapeutic potential in the treatment of asthmatic and inflammatory conditions.

The antinociceptive activity of Polygonatum verticillatum rhizomes in pain models

AIM OF THE STUDY

The current study was designed to establish the pharmacological rationale for the traditional use of the rhizomes of Polygonatum verticillatum in the treatment of painful conditions and as a plant diuretic.

MATERIALS AND METHODS

The crude methanolic extract of the rhizomes of Polygonatumverticillatum (PR) was tested in various established pain models in rodents at 50, 100 and 200mg/kg i.p. while the diuretic activity was assessed at 300 and 600 mg/kg p.o. in rats.

RESULTS

PR demonstrated significant reduction (14-72%) in the number of writhes induced by acetic acid in a dose-dependent manner. When nociceptive threshold was measured in the formalin test, PR strongly attenuated the formalin-induced flinching behaviour in both phases (6-30% in first phase while 12-72% in second phase). Central involvement in the analgesic profile of PR was confirmed by the hot plate test, in which PR elicited a significant (P<0.01) analgesic activity by increasing latency time. However, an opioid receptor antagonist, naloxone (2mg/kg s.c.) strongly antagonized the antinociceptive activity of PR. As a plant diuretic, PR showed mild but statistically insignificant diuretic activity at 300 mg/kg. The crude extract and solvent fractions of the plant contained reasonable quantity of total saponin and alkaloid contents.

CONCLUSIONS

The mechanisms underlying the analgesic action of PR shows that the opioid dependant central mediation has synergistic effect by enforcing the peripheral analgesic effects. Interestingly, our findings not only substantiated the folk use of the plant as an analgesic but also reported for the first time in the whole genus.