In vitro antifungal activity of 2-(3,4-dimethyl-2,5-dihydro-1H-pyrrol-2-yl)-1-methylethyl pentanoate, a dihydropyrrole derivative

Ethnobotanical uses and phytochemical, biological, and toxicological profiles of Datura metel L.: A review

Datura metel L., a recognized poisonous plant in the Solanaceae family, is widely distributed in the world. Traditionally, D. metel is used in many diseases, including neurological and heart diseases; fever; catarrh; pain; diarrhea; skin diseases; chronic bronchitis; asthma; digestive disorders; and so on. It possesses many important phytochemicals that can be used to treat various types of diseases. This review aims at summarizing the traditional uses, phytochemical, biological, and toxicological profiles of D. metel based on the database reports. For this, an up-to-date (till March 20, 2023) search was made in the databases: PubMed, Google Scholar, Science Direct, Scopus, and MedLine, with relevant keywords for the published evidence. Findings suggest that the plant has many traditional uses, such as a cure for madness, epilepsy, psoriasis, heart diseases, diarrhea, mad dog bites, indigestion, etc. It possesses various important phytochemicals, including withanolides, daturaolone, datumetine, daturglycosides, ophiobolin A, baimantuoluoline A, and many others. D. metel has many important biological activities, including antioxidant, anti-inflammatory, anti-microbial, insecticidal, anti-cancer, anti-diabetic, analgesic, anti-pyretic, neurological, contraceptive, and wound healing capacity. In conclusion, the toxic plant, D. metel, can be considered a potential source of phyto-therapeutic lead compounds.

A Review on Antifungal Efficiency of Plant Extracts Entrenched Polysaccharide-Based Nanohydrogels

Human skin acts as a physical barrier; however, sometimes the skin gets infected by fungi, which becomes more severe if the infection occurs on the third layer of the skin. Azole derivative-based antifungal creams, liquids, or sprays are available to treat fungal infections; however, these formulations show various side effects on the application site. Over the past few years, herbal extracts and various essential oils have shown effective antifungal activity. Additionally, autoxidation and epimerization are significant problems with the direct use of herbal extracts. Hence, to overcome these obstacles, polysaccharide-based nanohydrogels embedded with natural plant extracts and oils have become the primary choice of pharmaceutical scientists. These gels protect plant-based bioactive compounds and are effective delivery agents because they release multiple bioactive compounds in the targeted area. Nanohydrogels can be applied to infected areas, and due to their contagious nature and penetration power, they get directly absorbed through the skin, quickly reaching the skin's third layer and effectively reducing the fungal infection. In this review, we explain various skin fungal infections, possible treatments, and the effective utilization of plant extract and oil-embedded polysaccharide-based nanohydrogels.

A New Family of Benzo[h]Chromene Based Azo Dye: Synthesis, In-Silico and DFT Studies with In Vitro Antimicrobial and Antiproliferative Assessment

The high biological activity of the chromene compounds coupled with the intriguing optical features of azo chromophores prompted our desire to construct novel derivatives of chromene incorporating azo moieties 4a-l, which have been prepared via a three-component reaction of 1-naphthalenol-4-[(4-ethoxyphenyl) azo], 1, with the benzaldehyde derivatives and malononitrile. The structural identities of the azo-chromene 4a-l were confirmed on the basis of their spectral data and elemental analysis, and a UV-visible study was performed in a Dimethylformamide (DMF) solution for these molecules. Additionally, the antimicrobial activity was investigated against four human pathogens (Gram-positive and Gram-negative bacteria) and four fungi, employing an agar well diffusion method, with their minimum inhibitory concentrations being reported. Molecules 4a, 4g, and 4h were discovered to be more efficacious against Syncephalastrum racemosum (RCMB 05922) in comparison to the reference drugs, while compounds 4b and 4h demonstrated the highest inhibitory activity against Escherichia coli (E. coli) in evaluation against the reference drugs. Moreover, their cytotoxicity was assessed against three different human cell lines, including human colon carcinoma (HCT-116), human hepatocellular carcinoma (HepG-2), and human breast adenocarcinoma (MCF-7) with a selection of molecules illustrating potency against the HCT-116 and MCF-7 cell lines. Furthermore, the molecular modeling results depicted the binding interactions of the synthesized compounds 3b and 3h in the active site of the E. coli DNA gyrase B enzyme with a clear SAR (structure-activity relationship) analysis. Lastly, the density functional theory's (DFTs) theoretical calculations were performed to quantify the energy levels of the Frontier Molecular Orbitals (FMOs) and their energy gaps, dipole moments, and molecular electrostatic potentials. These data were utilized in the chemical descriptor estimations to confirm the biological activity.

Natural Products as Fungicide and Their Role in Crop Protection

Seeking solutions from nature for solving one and all problems is the age-old practice for mankind, and natural products are proved to be the most effective one for keeping up the balance of development as well as the “healthy, wealthy, and well” condition of mother nature. Fungal pathogens are proved to be a common and popular contaminant of agroecosystem that approximately causes 70–80% of total microbial crop loss. To meet the proper global increasing need of food products as a result of population explosion, managing agricultural system in an eco-friendly and profitable manner is the prime target; thus the word “sustainable agriculture” plays it part, and this package is highly effective when coupled with nature-derived fungicidal products that can minimize the event of fungal infections in agrarian ecosystem. Present study enlists the most common and effective natural products that might be of plant or microbial origin, their mode of action, day-by-day development of phytopathogenic resistance against the prevailing fungicides, and also their role in maintenance of sustainability of agricultural practices with special emphasis on their acceptance over the synthetic or chemical one. A large number of bioactive compounds ranging from direct plant (both cryptogams algae and moss and phanerogams)-derived natural extracts, essential oil of aromatic plants, and low-molecular-weight antimicrobial compounds known as phytoalexins to secondary metabolites that are both volatile and nonvolatile organic compounds of microbes (fungal and actinobacterial members) residing inside the host tissue, called endophyte, are widely used as agricultural bioweapons. The rhizospheric partners of plant, mycorrhizae, are also a prime agent of this chemical warfare and protect their green partners from fungal invaders and emphasize the concept of “sustainable agriculture.”

Chemoenzymatic Synthesis, Nanotization, and Anti-Aspergillus Activity of Optically Enriched Fluconazole Analogues

Despite recent advances in diagnostic and therapeutic methods in antifungal research, aspergillosis still remains a leading cause of morbidity and mortality. One strategy to address this problem is to enhance the activity spectrum of known antifungals, and we now report the first successful application of Candida antarctica lipase (CAL) for the preparation of optically enriched fluconazole analogues. Anti-Aspergillus activity was observed for an optically enriched derivative, (-)-S-2-(2',4'-difluorophenyl)-1-hexyl-amino-3-(1‴,2‴,4‴)triazol-1‴-yl-propan-2-ol, which exhibits MIC values of 15.6 μg/ml and 7.8 μg/disc in broth microdilution and disc diffusion assays, respectively. This compound is tolerated by mammalian erythrocytes and cell lines (A549 and U87) at concentrations of up to 1,000 μg/ml. When incorporated into dextran nanoparticles, the novel, optically enriched fluconazole analogue exhibited improved antifungal activity against Aspergillus fumigatus (MIC, 1.63 μg/ml). These results not only demonstrate the ability of biocatalytic approaches to yield novel, optically enriched fluconazole derivatives but also suggest that enantiomerically pure fluconazole derivatives, and their nanotized counterparts, exhibiting anti-Aspergillus activity may have reduced toxicity.

In vitro antifungal activity and probable fungicidal mechanism of aqueous extract of Barleria grandiflora

Barleria grandiflora Dalz. (Acanthaceae) is being used in India to treat different types of disorders including skin infections. Therefore, there are good possibilities to find antifungal compounds in its extracts with novel mechanism of action. The main objectives of the present study were to evaluate the antifungal activity of plant extracts and to study its effects on metabolic pathways of A. fumigatus. The microbroth dilution assay was used to explore antifungal activity and MIC of various extracts. Metabolic profiles of control and treated cultures were collected from Q-TOF-MS interfaced with HPLC. Affected metabolic pathways of A. fumigatus after the treatment were analyzed by discrimination analysis of mass data. Antifungal activities were observed in hot and cold water extracts of the plant. Hot water extract of B. grandiflora showed significant activity against tested fungi in the range 0.625-1.25 mg/mL. Partial least discrimination analysis revealed that the hot water plant extract downregulated amino acid, glyoxylate pathway, and methylcitrate pathways at the same time due to the synergistic effects of secondary metabolites. Hot water extract also downregulated several other metabolic pathways unique to fungi indicating its specific activity toward fungi. B. grandiflora showed promising antifungal activity which can further be exploited by identification of active compounds, to inhibit the specific fungal pathways and development of novel therapeutic antifungal drugs.

Quantitative analysis of catechins in Saraca asoca and correlation with antimicrobial activity

Herbal medicines are highly complex and have unknown mechanisms in diseases treatment. Saraca asoca (Roxb.), De. Wild has been recommended to treat gynecological disorders and used in several commercial polyherbal formulations. In present study, efforts have been made to explore antimicrobial activity and its co-relation with the distributions of catechins in the organs of S. asoca using targeted MS/MS. Eight extracts (cold and hot water) from four different organs of S. asoca and two drugs were prepared and antimicrobial activity was assessed by microbroth dilution assay. Quantitative and qualitative analysis of catechins in crude extracts was done by using targeted and auto-MS/MS and correlated with antimicrobial activity. (+)-Catechin and (+)-epicatechin and their biosynthesis related compound were found to be up-regulated in regenerated bark and leaves extracts. (−)-Epigallocatechin was found to be significantly higher in bark water extract as compared to others but showed low antimicrobial activity. Result showed down-regulation of (−)-epigallocatechin and up-regulation of (+)-catechin and (+)-epicatechin in the regenerated bark and leaves of S. asoca. It might be the contributing factor in the antimicrobial activity of regenerated bark and leaves of the plant. The concentration of (+)-epicatechin in processed drugs (Ashokarishta) from Baidyanath was found to be seven times higher than that of Dabur Pvt. Ltd., but no antimicrobial activity was observed, indicating the variations among the plant based drugs. This will be helpful in rational use of S. asoca parts. Furthermore, the analytical method developed is sensitive, repeatable and reliable; therefore, it is suitable for quality control of herbal drugs.

Proteomic characterization of Aspergillus fumigatus treated with an antifungal coumarin for identification of novel target molecules of key pathways

A synthetic coumarin, N,N,N-triethyl-11-(4-methyl-2-oxo-2H-chromen-7-yloxy)-11-oxoundecan-1-aminium bromide (SCD-1), having potent activity against pathogenic Aspergilli (MIC90 15.62 μg/mL), was investigated to identify its molecular targets in the pathogen. The proteome of Aspergillus fumigatus was developed after treatment with sublethal doses of compound and analyzed. The results demonstrated 143 differentially expressed proteins on treatment with SCD-1. The expression of four proteins, namely cell division control protein, ubiquitin-like activating enzyme, vacuolar ATP synthase catalytic subunit A, and UTP-glucose-1-phosphate uridylyltransferase of A. fumigatus, was completely inhibited, whereas there were 13 newly expressed and 96 overexpressed proteins, mainly belonging to stress pathway. The treatment of A. fumigatus with SCD-1 also led to attenuation of proteins involved in cell replication and other important biosynthetic processes, including riboflavin biosynthesis, which has been pathogen-specific. In addition to key enzymatic players and antioxidants, nine hypothetical proteins were also identified, seven of which have been novel, being described for the first time. As no cellular functions have yet been described for these hypothetical proteins, their alteration in response to SCD-1 provides significant information about their putative roles in pathogen defense.

Antifungal constituents isolated from the seeds of Aegle marmelos

Antifungal constituents, 2-isopropenyl-4-methyl-1-oxa-cyclopenta[b]anthracene-5,10-dione and (+)-4-(2'-hydroxy-3'-methylbut-3'-enyloxy)-8H-[1,3]dioxolo[4,5-h]chromen-8-one in addition to known compounds imperatorin, beta-sitosterol, plumbagin, 1-methyl-2-(3'-methyl-but-2'-enyloxy)-anthraquinone, beta-sitosterol glucoside, stigmasterol, vanillin and salicin were isolated during phytochemical investigation on seeds of Aegle marmelos Correa.

Tuning anti-microbial activity of poly(4-vinyl 2-hydroxyethyl pyridinium) chloride by anion exchange reactions

A series of new bioactive polymers with pendant choline analogous group was prepared by anion exchange reaction direct at the quaternary nitrogen of the polycation. Poly(4-vinyl 2-hydroxyethyl pyridinium) chloride was prepared in situ by simultaneous polymerization and quaternization of 4-vinyl pyridine with 2-chloroethanol that also acts as catalyst. The counter anion (Cl(-)) of the polycation was exchanged by anion exchange reaction with Br(-), (-)OH, (-)SH, NO(3) (-), BF(4) (-) or CF(3)COO(-). Evidence of anion exchange was obtained by the characterization of the resultant polymers. The nature of the counter anion has profound effect on their properties including strong anion-dependent anti-microbial activity against bacteria and fungus. Polymer containing (-)OH was observed to be the most potent anti-microbial agent with the lowest minimum inhibitory concentration against both the classes of microbes studied.

Anion effects on anti-microbial activity of poly[1-vinyl-3-(2-sulfoethyl imidazolium betaine)]

Recent investigations in the anti-microbial properties of the functional polymers are predominantly focused on the structure of the cationic moieties. In the present study, we investigated that the nature of the anion present in polysulfobetaines affects activity against certain microorganisms and their anti-microbial properties have been rationalized in terms of the structure-activity relationship. Vinyl imidazolium-based polysulfobetaines were prepared by the quaternization of poly(N-vinyl imidazole) with sodium salt of 2-bromo ethanesulfonic acid. The bromide counter anion of the resulting polymer was exchanged with different anions to generate a series of polymers. These were characterized by FTIR, DSC, XRD, SEM, elemental analysis (C, H, N and S) and viscosity measurements. The anti-microbial activity studies were carried against three fungi (Aspergillus niger, Byssochlamys fulva and Mucor circenelliods) and two bacteria (Bacillus coagulans BTS-3 and Pseudomonas aeruginosa BTS-2). The nature of the anion affects the structure of polysulfobetaine by realignment of polymer chains. The anion-dependent anti-microbial properties of polysulfobetaines result from the interaction of the microbes at the polymer interface.

Preparation and characterization of N-heterocyclic chitosan derivative based gels for biomedical applications

The novel N-heterocyclic chitosan aerogel derivatives were prepared by reacting 79% deacetylated chitosan separately with 4-pyridinecarboxaldehyde and 2,6-pyridinedicarboxaldehyde followed by subsequent solvent exchange into acetone, filteration and lyophilization. The identity of the Schiff bases was confirmed by UV-vis absorption spectroscopy and Fourier transform infrared (FTIR) spectroscopy. The N-heterocyclic chitosan derivatives were evaluated by X-ray diffraction (XRD), thermo-gravimetric analysis (TGA), differential scanning calorimetry (DSC), scanning electron microscopy (SEM), rheological studies and biological activity. Overall, the N-heterocyclic chitosan derivative based gels open new perspectives in biomedical applications.

Natural products--antifungal agents derived from plants

A new spectrum of human fungal infections is increasing due to increased cancer, AIDS, and immunocompromised patients. The increased use of antifungal agents also resulted in the development of resistance to the present drugs. It makes necessary to discover new classes of antifungal compounds to cure fungal infections. Plants are rich source of bioactive secondary metabolites of wide variety such as tannins, terpenoids, saponins, alkaloids, flavonoids, and other compounds, reported to have in vitro antifungal properties. Since the plant kingdom provides a useful source of lead compounds of novel structure, a wide-scale investigation of species from the tropics has been considered. Therefore, the research on natural products and compounds derived from natural products has accelerated in recent years due to their importance in drug discovery. A series of molecules with antifungal activity against different strains of fungus have been found in plants, which are of great importance to humans. These molecules may be used directly or considered as a precursor for developing better molecules. This review attempts to summarize the current status of important antifungal compounds from plants.

Post-antifungal effects of the antifungal compound 2-(3,4-dimethyl-2,5-dihydro-1H-pyrrol-2-yl)-1-methylethyl pentanoate on Aspergillus fumigatus

The post-antifungal effect (PAFE) of the antifungal compound 2-(3,4-dimethyl-2,5-dihydro-1H-pyrrol-2-yl)-1-methylethyl pentanoate (DHP) upon Aspergillus fumigatus was investigated. The conidia of A. fumigatus were exposed to DHP at concentrations of 1× and 4× MIC90 for variable times at 37 °C. Amphotericin B (AmB)-treated or drug-free controls were included in the study. DHP as well as AmB exposure resulted in prolonged lag phases of the turbidimetric growth curves. Both the treatments gave rise to delayed growth, with lag phases of 11 h upon treatment with a concentration of 4× MIC90 for 4 h. Furthermore, it was observed that DHP inhibited the expression of three A. fumigatus secretory proteins of 18, 42 and 55 kDa. One protein of 42 kDa was found to be a metalloprotease, which is an important virulence factor. Analysis of time-dependent antigenic profiles showed the early expression of high-molecular-mass antigens. Expression of low-molecular-mass antigens started after 24 h culture. The antigens of A. fumigatus that are expressed during the early phase of growth were observed to be adversely affected after treatment with DHP. Although the mechanism of action of DHP to inhibit these proteins/antigens is unknown, the observations may be valuable to understand their role in the virulence of the pathogen, as well as the antigen-mediated responses caused by A. fumigatus.

An antifungal protein from Escherichia coli

A cytosolic protein was purified fromEscherichia coliBL21 that demonstrated potent antifungal activity against pathogenic strains ofAspergillus fumigatus,Aspergillus flavus,Aspergillus nigerandCandida albicans. The MIC of purified protein fromE. coliBL21 (PPEBL21) againstAspergillusspecies andC. albicanswas 1.95–3.98 and 15.62 μg ml−1, respectively.In vitrotoxicity tests demonstrated no cytotoxicity of PPEBL21 to human erythrocytes up to the tested concentrations of 1250 μg ml−1. Amphotericin B was lethal to 100 % of human erythrocytes at a concentration of 37.5 μg ml−1. The N-terminal amino acid sequence of PPEBL21 was found to be DLAEVASR, which showed 75 % sequence similarity with alcohol dehydrogenase of yeast. Mass fingerprinting by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry also substantiated these observations. The results suggested thatE. coliBL21 might be an important bioresource of lead molecules for developing new peptide-based therapies for treating fungal infections.

Efficacy of 2-(3,4-dimethyl-2,5-dihydro-1h-pyrrole-2-yl)-1-methylethyl pentanoate in a murine model of invasive aspergillosis

2-(3,4-Dimethyl-2,5-dihydro-1H-pyrrole-2-yl)-1-methylethyl pentanoate, an antifungal compound, was found to be nontoxic to RAW cells up to a concentration of 312.5 microg/ml, whereas amphotericin B was lethal to all cells at 37.5 microg/ml. The treatment of Aspergillus fumigatus-infected mice with a dose of 200.0 mg of compound/kg of body weight increased their survival rate by 60%, with a decrease in CFU in organ tissues. The protection afforded by the compound against experimental aspergillosis was found to be dose dependent.