Functionally substituted 2-aminothiazoles as antimicrobial agents: in vitro and in silico evaluation

Nine new functionally substituted derivatives of 2-aminothiazole were evaluated for antimicrobial activity using microdilution method against the panel of eight bacterial and eight fungal strains. Evaluation of antibacterial activity revealed that compounds are potent antibacterial agents, more active than ampicillin and streptomycin except of some compounds against B. cereus and En. cloacae. The best compound appeared to be compound 8. The most sensitive bacteria appeared to be En. cloacae, while L. monocytogenes was the most resistant. Compounds also exhibited good antifungal activity much better than two reference drugs, ketoconazole and bifonazole. Compound 1 exhibited the best antifungal activity. The most sensitive fungus was T. viride, while A. fumigatus was the most resistant. Bacteria as well as fungi in general showed different sensitivity towards compounds tested. Molecular docking studies revealed that MurB inhibition is probably involved in the mechanism of antibacterial activity, while CYP51 of C. albicans is responsible for the mechanism of antifungal activity. Finally, it should be mentioned that all compounds displayed very good druglikeness scores.

Characterization, In Vitro Biological Activity and In Vivo Cardioprotective Properties of Trametes versicolor (L.:Fr.) Quél. Heteropolysaccharides in a Rat Model of Metabolic Syndrome

The present study aimed to examine the biological activity and cardioprotective potential of Trametes versicolor heteropolysaccharides (TVH) in a rat model of metabolic syndrome (MetS). This study included 40 Wistar rats divided into 5 groups: CTRL-healthy non-treated rats; MetS-non-treated rats; and H-TV, M-TV and L-TV-rats with MetS treated with either 300, 200 or 100 mg/kg TVH per os for 4 weeks. After finishing the treatment, we conducted an oral glucose tolerance test (OGTT), hemodynamic measurements and the animals were sacrificed, hearts isolated and subjected to the Langendorff technique. Blood samples were used for the determination of oxidative stress parameters, lipid status and insulin levels. We showed that α-amylase inhibition was not the mode of TVH antidiabetic action, while TVH showed a moderate inhibition of pathogenic microorganisms' growth (MIC 8.00 mg·mL^-1; MBC/MFC 16.00 mg·mL^-1). H-TV and M-TV significantly reduced the level of prooxidants (O₂^-, H₂O₂, TBARS; p < 0.05), increased antioxidants activity (SOD, CAT, GSH; p < 0.05), reduced blood pressure (p < 0.05), improved glucose homeostasis in the OGTT test (p < 0.05), and ejection fraction (p < 0.05) and cardiac contractility (p < 0.05) compared to MetS (p < 0.05). Moreover, TVH treatment normalized the lipid status and decreased insulin levels compared to MetS rats (p < 0.05). The obtained results demonstrated that the TVH may be considered a useful agent for cardioprotection in MetS conditions.

Alpha to Omicron (Variants of Concern): Mutation Journey, Vaccines, and Therapy

Coronavirus disease 2019 caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) initially emerged in December 2019 and has subsequently expanded globally, leading to the ongoing pandemic. The extensive spread of various SARS-CoV-2 variants possesses a serious public health threat. An extensive literature search along with deep analysis was performed to describe and evaluate the characteristics of SARS-CoV-2 variants of concern in relation to the effectiveness of the current vaccines and therapeutics. The obtained results showed that several significant mutations have evolved during the COVID-19 pandemic. The developed variants and their various structural mutations can compromise the effectiveness of several vaccines, escape the neutralizing antibodies, and limit the efficiency of available therapeutics. Furthermore, deep analysis of the available data enables the prediction of the future impact of virus mutations on the ongoing pandemic along with the selection of appropriate vaccines and therapeutics.

Pineapple by-products as a source of bioactive compounds with potential for industrial food application

Pineapple is a tropical fruit consumed fresh or processed into various food products. However, the peel and crown of this fruit are not industrially exploited, thus generating tons of by-products that represent an economic and environmental concern. In order to promote the upcycling of these by-products, this work aimed to characterize the phenolic profile of its hydroethanolic extracts obtained from pineapple peel and crown leaves and to evaluate their in vitro bioactivity. The HPLC-DAD-ESI/MS analysis allowed the identification of 25 phenolic compounds, including phenolic acids and flavonoids. The antioxidant, cytotoxic, and antimicrobial activity assays highlighted the peel extract as the most promising and, therefore, it was incorporated into a traditional Portuguese pastry cake as a functional ingredient. The nutritional parameters of the developed food were not affected by the incorporation of the extract, but it promoted the antioxidant activity during its shelf-life. Overall, pineapple peel and crown appeared as promising by-products to be exploited by the food industry, which can be achieved through a circular economy approach.

Bioactive Compounds and Functional Properties of Herbal Preparations of Cystus creticus L. Collected From Rhodes Island

The members of Cystus genus are perenial shrubs with a well-established use in traditional medicine. Among these, C. creticus is the most popular, herbal preparations obtained from its aerial parts being recognized as antimicrobial, antitumor and anti-inflammatory agents. The present study aimed to evaluate phytochemical profile and bioactive potential of aqueous and hydroethanolic extracts of C. creticus aerial parts harvested from two different areas of Rhodes island. LC-DAD-ESI/MSn analysis revealed the presence of myricetin and quercetin glycosides as main compounds, especially in aqueous extracts, being probably responsible for their enhanced antioxidant and antimicrobial potential. On the other side, hydroethanolic preparations exerted a strong anti-inflammatory and anti-biofilm activity. Our findings suggest that the use of solvents with intermediate polarity can assure the best recovery of bioactive compounds from C. creticus, increasing the extraction yield for other non-phenolic compounds which can enhance therapeutic potential of the extract through a synergistic action.

Phlomis fruticosa L. exerts in vitro antineurodegenerative and antioxidant activities and induces prooxidant effect in glioblastoma cell line

Despite the significant advances in drug development we are witnessing the inability of health systems to combat both neurodegenerative diseases and cancers, especially glioblastoma. Hence, natural products are comprehensively studied in order to provide novel therapeutic options. This study aimed to explore anti-neurodegenerative and anti-glioblastoma potential of extract of Phlomis fruticosa L. using in vitro model systems. It was found that the methanol extract of P. fruticosa was able to efficiently reduce activities of enzymes linked to neurodegenerative disease including acetylcholinesterase, butyrylcholinesterase and tyrosinase. Furthermore, P. fruticosa extract has shown excellent antioxidant potential, as evidenced by six different methods. Analysis of cytotoxic effect of P. fruticosa extract on A172 glioblastoma cell line revealed that the concentration of the extract necessary for 50 % inhibition of A172 growth (IC₅₀) was 710 μg/mL. The extract did not induce changes in proliferation and morphology of A172 glioblastoma cells. On the other side, production of ROS was increased in A172 cells treated with the extract. Observed cytotoxic effect of P. fruticosa extract might be based on increase in ROS generation upon treatment. Quantitative chemical analysis revealed the presence of twelve different polyphenols with the cis 3-O-caffeoylquinic acid being the most abundant. This study provided scientific evidence for further exploration of P. fruticosa as a promising natural anti-neurodegenerative therapeutic option.

A Prospective of Multiple Biopharmaceutical Activities of Procyanidins-Rich Uapaca togoensis Pax Extracts: HPLC-ESI-TOF-MS Coupled with Bioinformatics Analysis

The article reports the chemical composition, antioxidant, six key enzymes inhibitory and antimicrobial activities of two solvent extracts (water and methanol) of leaves and stem bark of Uapaca togoensis. For chemical composition, methanol extract of stem bark exhibited significant higher total phenolic (129.86 mg GAE/g) and flavanol (10.44 mg CE/g) contents. Methanol extract of leaves and water extract of stem bark showed high flavonoids (20.94 mg RE/g) and phenolic acid (90.40 mg CAE/g) content, respectively. In addition, HPLC-ESI-TOF-MS analysis revealed that U. togoensis was rich in procyanidins. The methanol and water extracts of stem bark had overall superior antioxidant activity; however, only methanol extract of stem bark showed higher inhibition of cholinesterase (AChE: 2.57 mg GALAE/g; BChE: 4.69 mg GALAE/g), tyrosinase (69.53 mg KAE/g) and elastase (2.73 mmol CE/g). Potent metal chelating ability was showed by water extract of leaves (18.94 mg EDTAE/g), higher inhibition of amylase was detected for water extracts of leaves (0.94 mmol ACAE/g) and stem bark (0.92 mmol ACAE/g). The tested extracts have shown wide-spectrum antibacterial properties and these effects have shown to be more effective against Aspergillus ochraceus, Penicillium funiculosum, Trichoderma viride, Bacillus cereus, Escherichia coli and Pseudomonas aeruginosa. The results revealed that the antioxidant, enzyme inhibitory and antimicrobial activities depended on the extraction solvents and the parts of plant. Bioinformatics analysis on the 17 major compounds showed modulation of pathway associated with cancer. In brief, U. togoensis might be valuable as potential source of natural agents for therapeutic application.

5-Benzyliden-2-(5-methylthiazol-2-ylimino)thiazolidin-4-ones as Antimicrobial Agents. Design, Synthesis, Biological Evaluation and Molecular Docking Studies

In this study, we report the design, synthesis, computational and experimental evaluation of the antimicrobial activity, as well as docking studies of new 5-methylthiazole based thiazolidinones. All compounds demonstrated antibacterial efficacy, some of which (1, 4, 10 and 13) exhibited good activity against E. coli and B. cereus. The evaluation of antibacterial activity against three resistant strains, MRSA, P. aeruginosa and E. coli, revealed that compound 12 showed the best activity, higher than reference drugs ampicillin and streptomycin, which were inactive or exhibited only bacteriostatic activity against MRSA, respectively. Ten out of fifteen compounds demonstrated higher potency than reference drugs against a resistant strain of E. coli, which appeared to be the most sensitive species to our compounds. Compounds 8, 13 and 14 applied in a concentration equal to MIC reduced P. aeruginosa biofilm formation by more than 50%. All compounds displayed antifungal activity, with compound 10 being the most active. The majority of compounds showed better activity than ketoconazole against almost all fungal strains. In order to elucidate the mechanism of antibacterial and antifungal activities, molecular docking studies on E. coli Mur B and C. albicans CYP51 and dihydrofolate reductase were performed. Docking analysis of E. coli MurB indicated a probable involvement of MurB inhibition in the antibacterial mechanism of tested compounds while docking to 14α-lanosterol demethylase (CYP51) and tetrahydrofolate reductase of Candida albicans suggested that probable involvement of inhibition of CYP51 reductase in the antifungal activity of the compounds. Potential toxicity toward human cells is also reported.

New insights on Phyllanthus reticulatus Poir. leaves and stem bark extracts: UPLC-ESI-TOF-MS profiles, and biopharmaceutical and in silico analysis

Our results could provide a great scientific starting point on the way from the bench to functional applications through the use of P. reticulatus, namely novel nutraceuticals, pharmaceuticals and cosmeceuticals.

2-Aryl-3-(6-trifluoromethoxy)benzo[d]thiazole-based thiazolidinone hybrids as potential anti-infective agents: Synthesis, biological evaluation and molecular docking studies

The search for new antimicrobial agents is greater than ever due to the perpetual threat of multidrug resistance in known pathogens and the relentless emergence of new infections. In this manuscript, ten thiazole-based thiazolidinone hybrids bearing a 6-trifluoromethoxy substituent on the benzothiazole core were synthesized and evaluated against a panel of four bacterial strains Salmonella typhimurium, Staphylococcus aureus, Escherichia coli and Listeria monocytogenes and three resistant strains Pseudomonas aeruginosa, E. coli and MRSA. The evaluation of minimum bactericidal and minimum inhibitory concentrations was accomplished by microdilution assay. As reference compounds ampicillin and streptomycin were employed. All compounds displayed antibacterial efficiencies with MBCs/MICs at 0.25-1 mg/mL and 0.12-1 mg/mL respectively while ampicillin displayed MBCs/MICs at 0.15-0.3 mg/mL and at 0.1-0.2 mg/mL respectively. MICs/MBC of streptomycin varied from 0.05 to 0.15 mg/mL and from 0.1 to 0.3 mg/mL respectively. The best overall effect was observed for compound h4, while compound h1 exhibited the highest effective action against E. coli (MIC/MBC 0.12/0.25 mg/ml) among all tested compounds.

Synthesis and Evaluation of Antimicrobial Activity and Molecular Docking of New N-1,3-thiazol-2-ylacetamides of Condensed Pyrido[3',2':4,5] furo(thieno)[3,2-d]pyrimidines

Background:

From the literature it is known that many derivatives of fused thienopyrimidines and furopyrimidines possess broad spectrum of biological activity.

Objectives:

The current studies describe the synthesis and evaluation of antimicrobial activity of some new N-1,3-thiazol-2-ylacetamides of pyrido[3',2':4,5]furo(thieno)[3,2-d]pyrimidines.

Methods:

By cyclocondensation of ethyl 1-aminofuro(thieno)[2,3-b]pyridine-2-carboxylates 1with formamide were converted to the pyrido[3',2':4,5]furo(thieno)[3,2-d]pyrimidin-7(8)-ones 2.Alkylation of compound 2 with 2-chloro-N-1,3-thiazol-2-ylacetamide led to the aimed N-1,3-thiazol-2-ylaceta-mides of pyrido[3',2':4,5]furo(thieno)[3,2-d]pyrimidines 3. Starting from compound 2 the relevant S-alkylated derivatives of pyrido[3',2':4,5]furo(thieno)[3,2-d]pyrimidines 6 were also synthesized.

Results:

All the compounds showed antibacterial activity to non-resistant strains. Compounds 3a-3m showed antibacterial activity with MIC/MBC at 0.08-2.31 mg/mL/0.11-3.75 mg/mL .The two most active compounds, 3j and 6b, appeared to be more active towards MRSA than the reference drugs. Half of the tested compounds appeared to be equipotent/more potent than ketoconazole and more potent than bifonazole. The docking analysis provided useful information about the interactions occurring between the tested compounds and the different enzymes.

Conclusion:

Gram-negative and Gram-positive bacteria and fungi showed different response towards tested compounds, indicating that different substituents may lead to different modes of action or that the metabolism of some bacteria/fungi was better able to overcome the effect of the compounds or adapt to it.

Revealing the astragalin mode of anticandidal action

Due to limited arsenal of systemically available antifungal agents, infections caused by Candida albicans are difficult to treat and the emergence of drug-resistant strains present a major challenge to the clinicians worldwide. Hence further exploration of potential novel and effective antifungal drugs is required. In this study we have explored the potential of a flavonoid, astragalin, in controlling the growth of C. albicans, in both planktonic and biofilm forms by microdilution method; and in regulating the morphological switch between yeast and hyphal growth. Astragalin ability to interfere with membrane integrity, ergosterol synthesis and its role in the regulation of genes encoding for efflux pumps has been addressed. In our study, astragalin treatment produced good antimicrobial and significant antibiofilm activity. Anticandidal activity of astragalin was not related to ERG11 downregulation, neither to direct binding to CYP51 enzyme nor was linked to membrane ergosterol assembly. Instead, astragalin treatment resulted in reduced expression of CDR1 and also affected cell membrane integrity without causing cytotoxic effect on human gingival fibroblast cells. Considering that astragalin-mediated decreased expression of efflux pumps increases the concentration of antifungal drug inside the fungal cells, a combinatorial treatment with this agent could be explored as a novel therapeutic option for candidiasis.

Synthesis and antimicrobial activity of new 2-piperazin-1-yl-N-1,3-thiazol-2-ylacetamides of cyclopenta[c]pyridines and pyrano[3,4-c]pyridines

In this study, we report the synthesis and antimicrobial activity of some new disubstituted piperazines. Thus, 3-chlorocyclopenta[c]pyridines and 6-chloropyrano[3,4-c]pyridine 1 under mild reaction conditions with piperazine gave the 3(6)-piperazine-substituted cyclopenta[c]pyridines and pyrano[3,4-c]pyridine 2. Furthermore, the latter, by alkylation with 2-chloro-N-1,3-thiazol-2-ylacetamide, led to the formation of the target compounds. The evaluation of the antibacterial activity revealed that 3k was the most potent compound. The most sensitive bacterium was found to be Listeria monocytogenes, whereas Staphylococcus aureus was the most resistant one. Three compounds, 3d, 3g, and 3k, were tested also against the following resistant strains: methicillin-resistant S. aureus (MRSA), Escherichia coli, and Pseudomonas aeruginosa. All three compounds appeared to be more potent than ampicillin against MRSA. Moreover, compound 3d showed a better activity than the reference drug ampicillin against P. aeruginosa, whereas 3g was more efficient against E. coli. The best antifungal activity was observed again for compound 3k. The most resistant fungi appeared to be Aspergillus fumigatus, whereas Trichoderma viride seemed the most sensitive one toward the compounds tested. Molecular docking studies on E. coli MurB, as well as on Candida albicans CYP51 and dihydrofolate reductase, were used for the prediction of the mechanisms of the antibacterial and antifungal activities, confirming the experimental results.

The Triazole Ring as a Privileged Scaffold for Putative Antifungals: Synthesis and Evaluation of a Series of New Analogues

The significant antifungal activity of a series of novel 1,2,4-triazole derivatives against different strains of Candida albicans, Candida krusei and Aspergillus fumigatus, compared to the commercial fungicides ketoconazole and itraconazole, is reported. Systemic mycosis and invasive fungal infections, whether from immunodeficiency or hospital-acquired infection, have been on an upward trend for several years. The 1,2,4-triazole ring substituted with other aromatic and heteroaromatic systems plays an important role in the field of antifungal drug discovery and development. Thus, an extensive series of 29 triazoles, substituted in different positions with a variety of aromatic rings, has been designed, synthesized, and evaluated for their fungicidal activity. Almost all the agents tested in vitro showed high activity against all examined fungal strains. It is noteworthy that, in the case of A. fumigatus, all the examined compounds achieved equal or higher antifungal activity than ketoconazole, but less activity than itraconazole. Among all the derivatives studied, the dichlorourea analogue and bromo-substituted triazole stand out as the most promising compounds. Quantitative structure-activity relationship (QSAR) models were built for a systematic structure-activity relationship (SAR) profile to explain and potentially explore the potency characteristics of 1,2,4-triazole analogues.

Chenopodium quinoa Willd. (quinoa) grains: A good source of phenolic compounds

The ingestion of bioactive compounds has revealed health benefits, namely in the prevention and/or treatment of several diseases. This work aims to characterize the phenolic profile of three colour varieties of Chenopodium quinoa Willd. grains (black, red and white), and also evaluate their cytotoxic and antimicrobial activity. All varieties revealed the presence of phenolic compounds, namely, quercetin and kaempferol derivatives. In this study, quinoa grains did not reveal any anti-proliferative capacity in tumour cell lines, and, as expected, they were devoid of any toxicity. All of the analysed extracts possessed antibacterial and antifungal activities (inhibitory and bactericidal/fungicidal) against the microbial strains considered, exhibiting promising values of minimum bactericidal concentrations (mean MBC 0.153-0.916 mg/mL) and minimum fungicidal concentrations (mean MFC 0.211-0.884 mg/mL). Quinoa varieties represent a good source of bioactive compounds, interfering beneficially in the organism, specifically as antimicrobial agents. Thus, these extracts could be used in the development of bioactive ingredients.

New vinyl-1,2,4-triazole derivatives as antimicrobial agents: Synthesis, biological evaluation and molecular docking studies

1,2,4-Triazole is a very important scaffold in medicinal chemistry due to the wide spectrum of biological activities and mainly antifungal activity of 1,2,4-triazole derivatives. The main mechanism of antifungal action of the latter is inhibition of 14-alpha-demethylase enzyme (CYP51). The current study presents synthesis and evaluation of eight triazole derivatives for their antimicrobial activity. Docking studies to elucidate the mechanism of action were also performed. The designed compounds were synthesized using classical methods of organic synthesis. The in vivo evaluation of antimicrobial activity was performed by microdilution method. All tested compounds showed good antibacterial activity with MIC and MBC values ranging from 0.0002 to 0.0069 mM. Compound 2 h appeared to be the most active among all tested with MIC at 0.0002-0.0033 mM and MBC at 0.0004-0.0033 mM followed by compounds 2f and 2g. The most sensitive bacterium appeared to be Xanthomonas campestris while Erwinia amylovora was the most resistant. The evaluation of antifungal activity revealed that all compounds showed good antifungal activity with MIC values ranging from 0.02 mM to 0.52 mM and MFC from 0.03 mM to 0.52 mM better than reference drugs ketoconazole (MIC and MFC values at 0.28-1.88 mM and 0.38 mM to 2.82 mM respectively) and bifonazole (MIC and MFC values at 0.32-0.64 mM and 0.64-0.81 mM). The best antifungal activity is displayed by compound 2 h with MIC at 0.02-0.04 mM and MFC at 0.03-0.06 mM while compound 2a showed the lowest activity. The results showed that these compounds could be lead compounds in search for new potent antimicrobial agents. Docking studies confirmed experimental results.

Antimicrobial Activity of Nitrogen-Containing 5-Alpha-androstane Derivatives: In Silico and Experimental Studies

We evaluated the antimicrobial activity of thirty-one nitrogen-containing 5-α-androstane derivatives in silico using computer program PASS (Prediction of Activity Spectra for Substances) and freely available PASS-based web applications (such as Way2Drug). Antibacterial activity was predicted for 27 out of 31 molecules; antifungal activity was predicted for 25 out of 31 compounds. The results of experiments, which we conducted to study the antimicrobial activity, are in agreement with the predictions. All compounds were found to be active with MIC (Minimum Inhibitory Concentration) and MBC (Minimum Bactericidal Concentration) values in the range of 0.0005–0.6 mg/mL. The activity of all studied 5-α-androstane derivatives exceeded or was equal to those of Streptomycin and, except for the 3β-hydroxy-17α-aza-d-homo-5α-androstane-17-one, all molecules were more active than Ampicillin. Activity against the resistant strains of E. coli, P. aeruginosa, and methicillin-resistant Staphylococcus aureus was also shown in experiments. Antifungal activity was determined with MIC and MFC (Minimum Fungicidal Concentration) values varying from 0.007 to 0.6 mg/mL. Most of the compounds were found to be more potent than the reference drugs Bifonazole and Ketoconazole. According to the results of docking studies, the putative targets for antibacterial and antifungal activity are UDP-N-acetylenolpyruvoylglucosamine reductase and 14-α-demethylase, respectively. In silico assessments of the acute rodent toxicity and cytotoxicity obtained using GUSAR (General Unrestricted Structure-Activity Relationships) and CLC-Pred (Cell Line Cytotoxicity Predictor) web-services were low for the majority of compounds under study, which contributes to the chances for those compounds to advance in the development.

Wild and Cultivated Centaurea raphanina subsp. mixta: A Valuable Source of Bioactive Compounds

Centaurea raphanina subsp. mixta (DC.) Runemark is a wild edible species endemic to Greece. This study evaluated the chemical composition and bioactive properties of wild and cultivated C. raphanina subsp. mixta plants. Wild plants had higher nutritional value than cultivated ones, whereas cultivated plants contained more tocopherols. Glucose and sucrose were higher in cultivated plants and trehalose in wild ones. Oxalic and total organic acids were detected in higher amounts in cultivated samples. The main fatty acids were α-linolenic, linoleic and palmitic acid, while wild plants were richer in polyunsaturated fatty acids. Two pinocembrin derivatives were the main phenolic compounds being detected in higher amounts in wild plants. Regarding the antioxidant activity, wild and cultivated plants were more effective in the oxidative haemolysis (OxHLIA) and thiobarbituric acid reactive substances (TBARS) assays, respectively. Moreover, both extracts showed moderate cytotoxicity in non-tumor cell lines (PLP2), while cultivated plants were more effective against cervical carcinoma (HeLa), breast carcinoma (MCF-7) and non-small lung cancer (NCI-H460) cell lines. Finally, wild plants showed higher antimicrobial activity than cultivated plants against specific pathogens. In conclusion, the cultivation of C.raphanina subsp. mixta showed promising results in terms of tocopherols content and antiproliferative effects, however further research is needed to decrease oxalic acid content.

Nutritional value, physicochemical characterization and bioactive properties of the Brazilian quinoa BRS Piabiru

Quinoa is a very interesting food due to its nutritional and chemical composition, as well as its bioactive properties, such as antioxidant and antimicrobial activity.

Exploiting the bioactive properties of γ-oryzanol from bran of different exotic rice varieties

The rice industry is one of the most significant food industries since rice is a widely consumed cereal in the world. As a result of this substantial production, the rice industry has a significant amount of side streams, including bran, representing millions of tons of raw materials mainly designated to animal feed. Rice bran is a rich source of γ-oryzanol, a bioactive compound with substantial health benefits. In this perspective, different bran rice samples from distinct germplasm origins (Philippines, Italy and Portugal) were studied for their γ-oryzanol content by HPLC-PDA, cytotoxicity in four human tumour cell lines, hepatotoxicity in a normal cell line and for their antimicrobial effects on different bacterial and fungal strains. The Ballatinao sample presented the strongest activity against all the tumour cell lines, and was also the sample showing the highest amount of γ-oryzanol, suggesting its contribution to the exhibited cytotoxic properties. Regarding the antimicrobial activity, the tested samples were able to inhibit the majority of bacterial and fungal strains, with the Portuguese Ceres sample being the one presenting the highest bacterial inhibition and the Maluit and Dinorado samples, the highest fungal inhibition. Overall, the results show that rice bran extracts may be considered as potential candidates for antimicrobial agents when incorporated into food matrices.

Chemical composition and bioactive properties of byproducts from two different kiwi varieties

Kiwis are an example of fruits with excellent bioactive properties worldwide appreciated and consumed generating tons of waste. Thus, the objective of this work was to compare two varieties of kiwi: Actinidia deliciosa cv. "Hayward" (green) and Actinidia spp. (red) regarding the nutritional value of their pulps, chemical composition and bioactivities of each pulp and peel. The results revealed that pulps have a high water content and low amount of other macronutrients. Both parts of red kiwi presented the highest tocopherols content and red kiwi pulp presented the highest content in ascorbic acid. In general, the peels exhibited the highest antioxidant activity and green kiwi peels showed cytotoxicity and anti-inflammatory activity, which could be related to its higher content in phenolic compounds, especially B-type (epi)catechin dimer. Therefore, kiwi components currently underutilized may be indicated as a source of natural functionalizing ingredients with several benefits for human health.

Novel Hit Compounds as Putative Antifungals: The Case of Aspergillus fumigatus

The prevalence of invasive fungal infections has been dramatically increased as the size of the immunocompromised population worldwide has grown. Aspergillus fumigatus is characterized as one of the most widespread and ubiquitous fungal pathogens. Among antifungal drugs, azoles have been the most widely used category for the treatment of fungal infections. However, increasingly, azole-resistant strains constitute a major problem to be faced. Towards this direction, our study focused on the identification of compounds bearing novel structural motifs which may evolve as a new class of antifungals. To fulfil this scope, a combination of in silico techniques and in vitro assays were implemented. Specifically, a ligand-based pharmacophore model was created and served as a 3D search query to screen the ZINC chemical database. Additionally, molecular docking and molecular dynamics simulations were used to improve the reliability and accuracy of virtual screening results. In total, eight compounds, bearing completely different chemical scaffolds from the commercially available azoles, were proposed and their antifungal activity was evaluated using in vitro assays. Results indicated that all tested compounds exhibit antifungal activity, especially compounds 1, 2, and 4, which presented the most promising minimum inhibitory concentration (MIC) and minimum fungicidal concentration (MFC) values and, therefore, could be subjected to further hit to lead optimization.

Bioactive properties of greenhouse-cultivated green beans (Phaseolus vulgaris L.) under biostimulants and water-stress effect

BACKGROUND

The scarcity of irrigation water is severely affecting global crop production. In this context, biostimulants are increasingly used as alternatives means against abiotic stress conditions. In this study, phenolic compounds composition and bioactive properties of common bean (Phaseolus vulgaris L.) plants grown under water stress conditions and biostimulants application were investigated.

RESULTS

Sixteen individual phenolic compounds were detected in both pods and seeds with a notable difference in their compositional profile. A significant effect on phenolic compounds content and composition was also observed for the biostimulants tested. Regarding the antibacterial activity, pods of the second harvest and seed extracts showed significant efficacy against Bacillus cereus, especially in water-stressed plants, where all biostimulant treatments were more effective than positive controls. Moreover, all biostimulant treatments for seed extracts of water-stressed plants were more effective against Staphylococcus aureus compared with ampicillin, whereas streptomycin showed the best results. Extracts from pods of the second harvest from normally irrigated plants showed the best results against the fungi tested, except for Penicillium verrucosum var. cyclopium. Finally, no significant cytotoxic effects were detected.

CONCLUSION

In conclusion, the biostimulants tested increased total phenolic compounds content compared with control treatment, especially in pods of the first harvest and seeds of water-stressed plants. Moreover, bioactive properties showed a varied response in regard to irrigation and biostimulant treatment. Therefore, biostimulants can be considered as a useful means towards increasing phenolic compounds content, and they may also affect the antimicrobial properties of pods and seeds extracts. © 2019 Society of Chemical Industry.

Chemical composition and bioactive properties of Sanguisorba minor Scop. under Mediterranean growing conditions

Sanguisorba minor Scop. is a perennial plant native to the Mediterranean region which exhibits several medicinal activities. In the present study, plant growth, chemical composition, and antitumor and antimicrobial properties of S. minor plants were evaluated under different growing conditions. In particular, plants were grown on different substrates, namely (A) peat, (B) peat : perlite (1 : 1) and (C) peat : perlite (2 : 1). The dry weight of the aerial parts and roots was higher for the peat treatment (A), whereas plant growth was severely affected in the peat : perlite (1 : 1) treatment (B). The major detected sugars were fructose and glucose, while the peat : perlite (2 : 1) treatment resulted in a significant increase of α-tocopherol, glucose and total sugars content, especially in the aerial parts. Oxalic acid and citric acid were the major organic acids detected, with a varied effect of growth substrate on organic acid profile. Growth substrate and plant part also had a significant effect on fatty acid composition, especially on linoleic acid and α-linolenic acid content which was higher in the peat : perlite (1 : 1) treatment in both aerial parts and roots. An impact on the composition of phenolic compounds was also observed, where the plants grown on peat : perlite (2 : 1) and peat : perlite (1 : 1) substrates had the highest content of individual and total phenolic compounds in their aerial parts and roots, respectively. Moreover, roots contained significantly higher amounts of phenolic compounds than the aerial parts. Moreover, plant extracts exhibited antiproliferative activity against four tumor cell lines (HeLa, HepG2, MCF-7 and NCI-H460) and a primary culture of porcine liver cells (PLP2), as well as significant antimicrobial properties. In conclusion, S. minor presented significant bioactive properties, while growth substrates affected the nutritional value, chemical composition, antitumor and antimicrobial properties of the species which could be probably attributed to the higher phenolic compound content and different compositions of phenolic compounds. Therefore, although the species is commonly found in the Mediterranean region, it is underexploited yet and its plant tissues could be a potential source of natural bioactive compounds with further use in pharmaceutical and medicinal applications.

Appendix A. dithioloquinolinethiones as new potential multitargeted antibacterial and antifungal agents: Synthesis, biological evaluation and molecular docking studies

Herein we report the design, synthesis, molecular docking study and evaluation of antimicrobial activity of ten new dithioloquinolinethiones. The structures of compounds were confirmed by ¹H NMR, ¹³C NMR and HPLC-HRMS. Before evaluation of their possible antimicrobial activity prediction of toxicity was performed. All compounds showed antibacterial activity against eight Gram positive and Gram negative bacterial species. All compounds appeared to be more active than ampicillin and almost all than streptomycin. The best antibacterial activity was observed for compound 8c 4,4,8-trimethyl-5-{[(4-phenyl-5-thioxo-4,5-dihydro-1,3,4-thiadiazol-2-yl)thio]acetyl}-4,5-dihydro-1H-[1,2]dithiolo[3,4c]quino lone-1-thione). The most sensitive bacterium En.cloacae followed by S. aureus, while L.monocytogenes was the most resistant. All compounds were tested for antifungal activity also against eight fungal species. The best activity was expressed by compound 8d (5-[(4,5-Dihydro-1,3-thiazol-2-ylthio)acetyl]-4,4-dimethyl-4,5-dihydro-1H-[1,2]dithiolo[3,4-c]quinoline-1-thione). The most sensitive fungal was T. viride, while P. verrucosum var. cyclopium was the most resistant one. All compounds were more potent as antifungal agent than reference compound bifonazole and ketoconazole. The docking studies indicated a probable involvement of E. coli DNA GyrB inhibition in the anti-bacterial mechanism, while CYP51ca inhibition is probably responsible for antifungal activity of tested compounds. It is interesting to mention that docking results coincides with experimental.

New Caffeic Acid Derivatives as Antimicrobial Agents: Design, Synthesis, Evaluation and Docking

Background:

Phenolic acids (caffeic-, ferulic and p-coumaric acid) are widely distributed in the plant kingdom and exhibit broad spectrum of biological activities, including antimicrobial activity.

Objective:

The goal of this paper is the synthesis of some caffeic acid derivatives selected based on computer-aided predictions and evaluate their in vitro antimicrobial properties against Gram positive and Gram negative bacteria and also a series of fungi.

Methods:

In silico prediction of biological activity was used to identify the most promising structures for synthesis and biological testing, and the putative mechanisms of their antimicrobial action. The designed compounds were synthesized using classical organic synthesis methods. The antimicrobial activity was studied using microdilution method.

Results:

Twelve tested compounds have shown good antibacterial activity. Five out of twelve tested compounds appeared to be more active than the reference drugs ampicillin and streptomycin. Despite that all compounds exhibited good activity against all bacteria tested, the sensitivity of bacteria towards compounds in general was different. The evaluation of antifungal activity revealed that all compounds were more active than ketoconazole, while seven compounds (2, 3, 4, 5, 7, 8 and 12) appeared to be more active than bifonazole. Docking results indicate that gyrase inhibition is the putative mechanism of antibacterial action while the inhibition of 14α-demethylase may be responsible for antifungal action. Prediction of cytotoxicity by PROTOX showed that compounds are not toxic (LD50 1000-2000 mg/kg).

Conclusion:

Thirteen compounds, from which six are new ones, were synthesized, and twelve compounds were tested for antimicrobial activity. The studied compounds appeared to be promising potent and non-toxic antimicrobials, which could be considered as leads for new pharmaceutical agents.

Novel antimicrobial agents' discovery among the steroid derivatives

Fourteen steroid compounds were in silico evaluated using computer program PASS as antimicrobial agents. The experimental studies evaluation revealed that all compounds have good antibacterial activity with MIC at range of 0.003-0.96 mg/mL and MBC 0.06-1.92 mg/mL. Almost all compounds except of compound 4 (3β-acetoxy-1^/-p-chlorophenyl-3^/-methyl-5α-androstano[17,16-d]pyrazoline) were more potent than Ampicillin, and they were equipotent or more potent than Streptomycine. All compounds exhibited good antifungal activity with MIC at 0.003-0.96 mg/mL and MFC at 0.006-1.92 mg/mL but with different sensitivity against fungi tested. According to docking studies 14-alpha demethylase inhibition may be responsible for antifungal activity. Prediction of toxicity by PROTOX and GUSAR revealed that compounds have low toxicity and can be considered as potential lead compounds for the further studies.

The Effect of In Vitro Digestion on Antioxidant, ACE-Inhibitory and Antimicrobial Potentials of Traditional Serbian White-Brined Cheeses

This study deals with the effect of in vitro digestion on the functional potential of traditional Serbian white-brined cheeses. The total antioxidant capacity, reducing power and iron (II) chelating properties as well as angiotensin-converting enyzme-inhibitory (ACE-inhibitory) and antimicrobial activities of traditional Serbian white-brined cheeses before and after in vitro digestion were assayed. The traditional cheeses had different antioxidant properties as well as different ACE-inhibitory activities. In vitro digestion improved the total antioxidant capacity (8.42⁻58.56 times) and the reducing power (by 17.90⁻99.30%) of investigated cheeses, whereas their chelating ability was slightly improved or unaffected after digestion. In vitro digestion reduced the ACE-inhibitory potential of water-soluble protein fractions, and digested water-insoluble fractions were the major source of ACE-inhibitory peptides. The digestates did not exhibit any antibacterial potential, whereas they showed moderate antifungal potential toward selected micromycetes. The best antifungal potential had Svrljig ovine cheese and Homolje cow cheese. The results of this study clearly point to a significant functionality of traditional white-brined cheeses.

Challenges of traditional herbal teas: plant infusions and their mixtures with bioactive properties

Five traditional and medicinal plants have been individually characterized and analyzed in terms of bioactivities to determine how these characteristics are modified when preparing blends.

Bioactive compounds content and antimicrobial activities of wild edible Asteraceae species of the Mediterranean flora under commercial cultivation conditions

Nine wild edible species belonging to Astreaceae family, native to the Mediterranean basin were tested for their chemical composition (phenolic compounds, tocopherols, and organic acids) and antimicrobial activities over two growing periods, apart from Scolymus hispanicus and Hedypnois cretica which were tested for only one growing period. Flavonoids were the most abundant phenolic compounds in all the species, except for the case of Taraxacum species where significant amounts of chicoric acid were detected, while phenolic compounds content increased in the 2nd growing period by 4.6-397.4% for the tested species. α- and β-tocopherols were the main tocopherols, apart from Taraxacum sp. where significant amounts of γ-and δ-tocopherols (18.32 and 16.31 μg/100 g fresh weight) were detected, while total tocopherols content either increased (Reicardia picroides, Picris echioides, Urospermum picroides, and Taraxacum officinale) or decreased (Hymenonema graecum, Sonchus oleraceus, Taraxacum sp.) in the 2nd growing period. Oxalic acid was the most abundant organic acid, with the highest content (972 mg/100 g fresh weight) being observed in H. graecum (L.) DC. in the 1st growing period. Moreover, with the exception of H. graecum and S. olearaceus, total organic acids content increased in the 2nd growing period. Significant antimicrobial activities were observed against Bacillus cereus, Salmonella typhimurium and Penicillium ochrochloron for all the studied species. In conclusion, the studied species showed great potential for commercial cultivation, while plant extracts could find use in the food industry as alternative food preservatives.

Suitability of lemon balm (Melissa officinalis L.) extract rich in rosmarinic acid as a potential enhancer of functional properties in cupcakes

Melissa officinalis (lemon balm) and its extracts have been frequently reported as possessing bioactive properties, offering the potential for use in development/enrichment of food products with additional functional capabilities, providing health benefits to consumers. The antioxidant, antibacterial and antifungal activity of lemon balm extract, as well as its potential hepatotoxicity were thoroughly evaluated. The extracts were then incorporated into cupcakes and their preserving effect, chemical composition, colour parameters and antioxidant activity were compared with those provided by potassium sorbate. In general, the variables with the largest differences among different storage times were energy level, sucrose, glucose, palmitic acid (C6:0) and oleic acid (C18:1n9). On the other hand, L∗ (top), a∗ (top), b∗ (top), pH, capric acid (C10:0) and lauric acid (C12:0) showed the greatest variation according to cupcake formulation. The results observed indicate that the lemon balm extract rich in rosmarinic acid can provide advantageous functional properties to bakery products.

New Benzothiazole-based Thiazolidinones as Potent Antimicrobial Agents. Design, synthesis and Biological Evaluation

BACKGROUND

Thiazole and benzothiazole derivatives, as well as thiazolidinones are very important scaffolds in medicinal chemistry. Literature has revealed that they possess a wide spectrum of biological activities including antimicrobial activity.

OBJECTIVE

The goal of this paper is the designing of new benzothiazole based thiazolidinones and the evaluation of their biological activities.

METHODS

The designed compounds were synthesized using classical organic synthesis methods. The antimicrobial activity was evaluated using the method of microdilution.

RESULTS

The twelve newly synthesized compounds showed antimicrobial properties. All compounds appeared to be more active than ampicillin in most studied strains and in some cases, more active than streptomycin. Antifungal activity, in most cases was also better than the reference drugs ketoconazole and bifonazole. The prediction of cytotoxicity revealed that the synthesized compounds were not toxic (LD50 350-1000 mg/kg of body weight). Docking studies on the antibacterial activity confirmed the biological results.

CONCLUSION

The twelve new compounds were synthesized and studied for their antimicrobial activity. The compounds appeared to be promising antimicrobial agents and could be the lead compounds for new, more potent drugs. According to the docking prediction, the compounds could be MurB inhibitors.

Nitrate Esters of Heteroaromatic Compounds as Candida albicans CYP51 Enzyme Inhibitors

Four heteroaromatic compounds bearing nitrate esters were selected using a virtual-screening procedure as putative sterol 14α-demethylase (CYP51) Candida albicans inhibitors. Compounds were examined for their inhibition on C. albicans growth and biofilm formation as well as for their toxicity. NMR spectroscopy studies, in silico docking, and molecular dynamics simulations were used to investigate further the selectivity of these compounds to fungal CYP51. All compounds exhibited good antimicrobial properties, indicated with low minimal inhibitory concentrations and ability to inhibit formation of fungal biofilm. Moreover, all of the compounds had the ability to inhibit growth of C. albicans cells. N-(2-Nitrooxyethyl)-1Η-indole-2-carboxamide was the only compound with selectivity on C. albicans CYP51 that did not exhibit cytotoxic effect on cells isolated from liver and should be further investigated for selective application in new leads for the treatment of candidiasis.

A natural food ingredient based on ergosterol: optimization of the extraction fromAgaricus blazei, evaluation of bioactive properties and incorporation in yogurts

A. blazeibioresidues can be used to obtain promising high value-added food additives, following a circular bioeconomy concept.

Antimicrobial and antioxidant properties of various Greek garlic genotypes

Recent studies show a significant variation in antioxidant and antimicrobial properties between the various garlic genotypes mostly due to differences in chemical composition and bioactive compounds content. The aim of the present study was to evaluate antioxidant properties and antimicrobial activity of garlics collected from the main cultivation areas of Greece, as well as to correlate this activity with their total phenolics content. Genotype G5 showed the highest total phenolics content, which was significantly correlated with the lowest EC₅₀ values for all the tested antioxidant activity assays. Antimicrobial activity was significant, especially against the bacteria Proteus mirabilis and Antibiotic resistant Escherichia coli. In conclusion, significant variation was observed between the studied garlic genotypes, indicating the importance of both growing conditions and genotype on bioactive properties of dry garlic bulbs. This variation could be further exploited in breeding programs in order to select elite genotypes with increased bioactive properties.

Apigenin-7-O-glucoside versus apigenin: Insight into the modes of anticandidal and cytotoxic actions

Bioactive potential of apigenin derivative apigenin-7-O-glucoside related to its antifungal activity on Candida spp. and cytotoxic effect on colon cancer cells was studied and compared with bioactive potential of apigenin. Antifungal activity was tested on 14 different isolates of Candida spp. using membrane permeability assay, measuring inhibition of reactive oxidative species and inhibition of CYP51 C. albicans enzyme. Cytotoxic potential of apigenin-7-O-glucoside was tested on colon cancer HCT116 cells by measuring cell viability, apoptosis rate and apoptosis- and colon cancer-related gene expression. Obtained results indicated considerable antifungal activity of apigenin-7-O-glucoside towards all Candida isolates. Breakdown of C. albicans plasma membrane was achieved upon treatment with apigenin-7-O-glucoside for shorter period of time then with apigenin. Reduction of intra- and extracellular reactive oxidative species was achieved with minimum inhibitory concentrations of both compounds, suggesting that reactive oxidative species inhibition could be a mechanism of antifungal action. None of the compounds exhibited binding affinity to C. albicans CYP51 protein. Besides, apigenin-7-O-glucoside was more effective compared to apigenin in reduction of cell's viability and induction of cell death of HCT116 cells. Treatment with both compounds resulted in chromatin condensation, apoptotic bodies formation and apoptotic genes expression in HCT116 cells, but the apigenin-7-O-glucoside required a lower concentration to achieve the same effect. Compounds apigenin-7-O-glucoside and apigenin displayed prominent antifungal potential and cytotoxic effect on HCT116 cells. However, our results showed that apigenin-7-O-glucoside has more potent activity compared to apigenin in all assays that we used.

Diarylheptanoids from Alnus viridis ssp. viridis and Alnus glutinosa: Modulation of Quorum Sensing Activity in Pseudomonas aeruginosa

Diarylheptanoids from the barks of Alnus viridis ssp. viridis (green alder) and Alnus glutinosa (black alder) were explored for anti-quorum sensing activity. Chemicals with anti-quorum sensing activity have recently been examined for antimicrobial applications. The anti-quorum sensing activity of the selected diarylheptanoids was determined using two biosensors, namely Pseudomonas aeruginosa PAO1 and Chromobacterium violaceum CV026. Although all of the investigated compounds negatively influenced the motility of P. aeruginosa PAO1, four were able to inhibit biofilm formation of this human opportunistic pathogen for 40-70 %. Three of the diarylheptanoids (3, 4, and 5) negatively influenced the biosynthesis of pyocyanin, which is under the control of quorum sensing. Platyphyllenone (7) and hirsutenone (5) were able to inhibit the biosynthesis of violacein in C. violaceum CV026, with 5 being able to inhibit the synthesis of both biopigments. Only one of the tested diarylheptanoids (1) was shown to significantly decrease the production of acyl homoserine lactones (AHL) in P. aeruginosa PAO1, more specifically, production of the long chain N-(3-oxododecanoyl)-l-HSL. On the other side, four diarylheptanoids (2-5) significantly reduced the synthesis of 2-alkyl-4-quinolones, part of the P. aeruginosa quinolone-mediated signaling system. To properly assess therapeutic potential of these compounds, their in vitro antiproliferative effect on normal human lung fibroblasts was determined, with doses affecting cell proliferation between 10 and 100 µg/mL. This study confirms that the barks of green and black alders are rich source of phytochemicals with a wide range of biological activities that could further be exploited as natural agents against bacterial contaminations and infections.

The chemical composition, nutritional value and antimicrobial properties of Abelmoschus esculentus seeds

Okra seeds present significant nutritional value and antimicrobial properties and could be proposed for innovative okra products and functional foods with antimicrobial and bioactive properties.

An insight into anti-biofilm and anti-quorum sensing activities of the selected anthocyanidins: the case study of Pseudomonas aeruginosa PAO1

Anti-biofilm activity of three anthocyanidins (pelargonidin, cyanidin and delphinidin) was evaluated for the first time at in vitro conditions. All the compounds reduced the formation of Pseudomonas aeruginosa PAO1 biofilm at low sub-MIC (0.125 MIC) with delphinidin (c 56.25 μg/mL) being the most active (43%). In comparison, ampicillin (c 93.75 μg/mL) and streptomycin (c 21.25 μg/mL) (used as positive controls) were considerably less effective at the same sub-MIC (8 and 12%, respectively). Furthermore, at 0.5 MIC (c 225 μg/mL) this anthocyanidin molecule partly reduced the bacterial protrusions. However, no any of the aforementioned compounds inhibited the production of pyocyanin by the bacterial strain P. aeruginosa PAO1. Taken all together, the delphinidin scaffold could be taken into consideration for the design of the novel and more effective anti-biofilm agents inspired by the anthocyanidins.

Bioactive formulations prepared from fruiting bodies and submerged culture mycelia of the Brazilian edible mushroom Pleurotus ostreatoroseus Singer

Pleurotus ostreatoroseus is a Brazilian edible mushroom whose chemical characterization and bioactivity still remain underexplored. In this study, the hydrophilic and lipophilic compounds as well as the antioxidant, anti-inflammatory and antimicrobial activities of formulations (ethanol extracts) prepared with its fruiting bodies and submerged culture mycelia were compared. The bioactive formulations contain at least five free sugars, four organic acids, four phenolic compounds and two tocopherols. The fruiting body-based formulation revealed higher reducing power, DPPH scavenging activity, β-carotene bleaching inhibition and lipid peroxidation inhibition in brain homogenates than the mycelium-based preparation, as well as higher anti-inflammatory and antimicrobial activities. The absence of hepatotoxicity was confirmed in porcine liver primary cells. These functional responses can be related to the levels of bioactive components including phenolic acids, organic acids and tocopherols.

Sensitivity of clinical isolates of Candida to essential oils from Burseraceae family

The aim of this study was to investigate the chemical composition and antifungal activity of four commercial essential oils from the Burseraceae family - two Boswellia carterii Flueck oils, Canarium luzonicum (Blume) A. Gray oil, and Commiphora myrrha (Nees) Engl oil, against most common Candida spp. recovered from the human oral cavity. The essential oil samples were analyzed by GC-FID and GC/MS. The analysis showed that major essential oils' components were α-pinene (23.04 % and 31.84 %), limonene (45.62 %) and curzerene (34.65 %), respectively. Minimum inhibitory (MIC) and minimum fungicidal (MFC) concentrations were determined using a microdilution standardized technique. All tested Candida spp. clinical isolates and ATCC strains showed susceptibility to tested essential oils in a dose dependent manner. The strongest antifungal activity was shown by essential oil of B. carterii, sample 2; the average MIC values ranged from 1.25 to 1.34 mg/ml, and MFC values ranged from 2.50 to 3.75 mg/ml, depending on the fungus. This study supports the possible use of essential oils from the Bursecaceae family in reduction and elimination of Candida spp. populations in patients with oral cavity fungal infections.