Natural Isatin Derivatives Against Black Fungus: In Silico Studies.

During this coronavirus pandemic, when a lot of people are already severely afflicted with SARS-CoV-19, the dispersion of black fungus is making it worse, especially in the Indian subcontinent. Considering this situation, the idea for an in silico study to identify the potential inhibitor against black fungal infection is envisioned and computational analysis has been conducted with isatin derivatives that exhibit considerable antifungal activity. Through this in silico study, several pharmacokinetics properties like absorption, distribution, metabolism, excretion, and toxicity (ADMET) are estimated for various derivatives. Lipinski rules have been used to observe the drug likeliness property, and to study the electronic properties of the molecules, quantum mechanism was analyzed using the density functional theory (DFT). After applying molecular docking of the isatin derivatives with sterol 14-alpha demethylase enzyme of black fungus, a far higher docking affinity score has been observed for the isatin sulfonamide-34 (derivative 1) than the standard fluconazole. Lastly, molecular dynamic (MD) simulation has been performed for 100 ns to examine the stability of the proposed drug complex by estimating Root Mean Square Deviation (RMSD), Radius of gyration (Rg), Solvent accessible surface area (SASA), Root Mean Square Fluctuation (RMSF), as well as hydrogen bond. Listed ligands have precisely satisfied every pharmacokinetics requirement for a qualified drug candidate and they are non-toxic, non-carcinogenic, and have high stability. This natural molecule known as isatin derivative 1 has shown the potential of being a drug for fungal treatment. However, the impact of the chemicals on living cells requires more investigation and research.

Liposomal nanoformulations with trans-caryophyllene and caryophyllene oxide: do they have an inhibitory action on the efflux pumps NorA, Tet(K), MsrA, and MepA?

This study aimed to evaluate the antibacterial and inhibitory action of NorA, Tet(K), MsrA and MepA efflux pumps in S. aureus strains using the sesquiterpenes named trans-caryophyllene and caryophyllene oxide, both isolated and encapsulated in liposomes. The antibacterial and inhibitory action of these efflux pumps was evaluated through the serial microdilution test in 96-well microplates. Each sesquiterpene and liposome/sesquiterpene was combined with antibiotics and ethidium bromide (EtBr). The antibiotics named norfloxacin, tetracycline and erythromycin were used. The 1199 B, IS-58, RN4220 and K2068 S. aureus strains carrying NorA, Tet(K), MsrA and MepA, respectively, were tested. In the fluorescence measurement test, K2068 S. aureus was incubated with the sesquiterpenes and EtBr, and the fluorescence emission by EtBr was measured. The tested substances did not show direct antibacterial activity, with MIC >1024 µg/mL. Nonetheless, the isolated trans-caryophyllene and caryophyllene oxide reduced the MIC of antibiotics and EtBr, indicating inhibition of NorA, Tet(K) and MsrA. In the fluorescence test, these same sesquiterpenes increased fluorescence emission, indicating inhibition of MepA. Therefore, the sesquiterpenes named trans-caryophyllene and caryophyllene oxide did not show direct antibacterial action; however, in their isolated form, they showed possible inhibitory action on NorA, Tet(K), MsrA and MepA efflux pumps. They may also act in antibiotic potentiation. Further studies are needed to identify the mechanisms involved in antibiotic potentiation and efflux pump inhibitory action.

Pharmacological potential of limonene against opportunistic fungi: Impact on Candida virulence.

The present article aims to evaluate the antifungal and antivirulence effect of the phytoconstituent Limonene against Candida spp. Antifungal assays were performed, where the concentration capable of inhibiting 50 % of fungal growth, the growth inhibition curve, the minimum fungicidal concentration, the evaluation of the modifying effect with fluconazole, the inhibitory effect of the substances on the morphological transition of Candida spp. and the statistical analysis of the results were determined. With this study, it was seen that limonene demonstrated growth inhibition for the strains tested and when associated the natural compound with Fluconazole, there was potentiation of the effect of the drug, since the inhibition of growth by the combination occurred at lower concentrations against all strains tested, when compared to the drug alone, which inhibited growth at the highest concentration. In the test to determine the Minimum Fungicidal Concentration of the products tested alone and in combination, it was found that in the case of Candida strains, growth inhibition by limonene occurred at a concentration of 1024 µg/mL. For Fluconazole, growth impairment ranged from > 1024 µg/mL to 256 µg/mL for the strains. And when combined, limonene potentiated the action of FCZ, making fungal colonization unfeasible at concentrations below 1024 µg/mL. Regarding the morphological transition from yeast to hyphae, limonene was used at concentrations of 1024 µg/mL and 512 µg/mL, and it was found that, for CA and CK, the filaments were reduced in number and size at the highest concentration and against CT, the morphological transition from yeast to hyphae/pseudohyphae was totally inhibited, and if compared to the growth control, limonene was able to reduce fungal growth at concentrations greater than 512 µg/mL. This compound has antimicrobial activity described, due to its ability to interfere in the gene expression of the fungus, the limited therapeutic options and the recent emergence of multidrug-resistant Candida species represent a significant challenge for human medicine and highlight the need for new therapeutic approaches, and in this study a great potential of limonene was revealed in relation to the perspective of increasing the efficiency of commercial drug. This work can bring an important contribution to the scientific database, while emphasizing that in-depth studies and tests on the subject, in order to better investigate its effectiveness and mechanisms by which they exert their effects, are still necessary.

Anticonvulsant effect of (±) citronellal possibly through the GABAergic and voltage-gated sodium channel receptor interaction pathways: In vivo and in silico studies.

This study aimed to investigate the anticonvulsant effects of citronellal (CIT) and possible underlying mechanisms through an isoniazid (INH)-induced seizure (convulsion) via in vivo and in silico studies. For this, convulsions were induced by the oral administration of INH (300 mg/kg) to the mice. The animals were treated orally with different doses of CIT (50, 100, and 200 mg/kg). Vehicle served as a negative control (NC), while diazepam (DZP) (2 mg/kg) and carbamazepine (CAR) (80 mg/kg) were provided (p.o.) as positive controls (PC). A combination therapy of CIT (middle dose) with DZP and CAR was also given to two separate groups of animals to estimate the synergistic or antagonistic effects. Molecular docking and visualization of ligand-receptor interactions are also estimated through different computational tools. The results of the in vivo study showed that CIT dose-dependently significantly (p < 0.05) exhibited a higher onset of seizures while reducing the frequency and duration of seizures in mice compared to the NC group. Besides these, in combination therapy, CIT significantly antagonized the activity of CAR and DZP, leading to a reduction in the onset of seizures and an increase in their frequency and duration compared to treatment with CAR and DZP alone. Additionally, molecular docking revealed that the CIT exhibited a moderate binding affinity (-5.8 kcal/mol) towards the GABAA receptor and a relative binding affinity (-5.3 kcal/mol) towards the voltage-gated sodium channel receptor by forming several bonds. In conclusion, CIT showed moderate anticonvulsant activity in INH-induced convulsion animals, possibly by enhancing GABAA receptor activity and inhibiting the voltage-gated sodium channel receptor.

Potential of the Blue Calm® food supplement in the treatment of alcohol withdrawal-induced anxiety in adult zebrafish (Danio rerio).

Alcohol use disorder (AUD) is characterized by a set of behavioral, cognitive, nutritional, and physiological phenomena derived from the uncontrolled use of alcoholic beverages. There are cases in which AUD is associated with anxiety disorder, and when untreated, it requires careful pharmacotherapy. Blue Calm® (BC) is a food supplement indicated to aid restorative sleep, which has traces of medicinal plant extracts, as well as myo-inositol, magnesium bisglycinate, taurine, and L-tryptophan as its main chemical constituents. In this context, this study aimed to evaluate the potential of the BC in the treatment alcohol withdrawal-induced anxiety in adult zebrafish (aZF). Initially, BC was submitted to antioxidant activity against 2,2-diphenyl-1-picrylhydrazyl radical. Subsequently, the aZF (n = 6/group) were treated with BC (0.1 or 1 or 10 mg/mL; 20 µL; p.o.), and the sedative effect and acute toxicity (96 h) were evaluated. Then, the anxiolytic-like effect and the possible GABAergic mechanism were analyzed through the Light & Dark Test. Finally, BC action was evaluated for treating alcohol withdrawal-induced anxiety in aZF. Molecular docking was performed to evaluate the interaction of the major chemical constituents of BC with the GABAA receptor. BC showed antioxidant potential, a sedative effect, was not toxic, and all doses of BC had an anxiolytic-like effect and showed potential for the treatment of alcohol withdrawal-induced anxiety in aZF. In addition to the anxiolytic action, the main chemical constituents of BC were confirmed in the molecular docking, thus suggesting that BC is an anxiolytic that modulates the GABAergic system and has pharmacological potential for the treatment of alcohol withdrawal-induced anxiety.

In vitro evaluation of the susceptibility of bacterial biofilms to hecogenin acetate.

Biofilms are a bacterial resistance strategy through which microorganisms organize themselves in the form of a colony fixed to a surface that is protected by a polymer matrix. Infectious diseases that result in biofilm formation have been considered a relevant public health problem due to the potential to increase patient morbidity and mortality, in addition to increasing the burden on health services. Such pathologies are treated with the use of antimicrobial drugs, the indiscriminate use of which has contributed to the process of bacterial resistance, demanding the need to invest in new alternatives to combat them. Based on this, the present work aimed to evaluate the anti-biofilm formation and eradication capacity of Hecogenin Acetate, a steroidal sapogenin of natural origin with important antibacterial properties. For this, we used strains of Streptococcus mutans INCQS 00,446 (ATCC 25,175), Enterococcus faecalis INCQS 00,018 (ATCC 14,506), Staphylococcus epidermidis INCQS 00,016 (ATCC 12,228), Staphylococcus aureus ATCC 25,923, Pseudomonas aeruginosa ATCC 9027 and Escherichia coli ATCC 259,223. The formation, formation inhibition and treatment assays were carried out in microdilution plates and revealed using the crystal violet method. Readings were carried out using absorbance at wavelengths of 492 nm. All tests were performed in triplicate and statistical analyzes were performed using Graphpad Prism v.5.0 software. It was observed that the bacterial strains used have a relevant capacity for biofilm formation, with the Gram positive ones identified in the present study as the best former. In the results of the analyzes with bacterial biofilm, it was identified that Hecogenin Acetate had a relevant antibiofilm capacity, and could therefore serve as a basis for further research into the development of new antimicrobial drugs.

Chemical composition, antifungal, and anti-virulence action of the stem bark of Hancornia speciosa Gomes (Apocynaceae) against Candida spp.

ETHNOPHARMACOLOGICAL RELEVANCE: Hancornia speciosa Gomes is a fruit and medicinal species used for treating infectious diseases of the genitourinary system. However, its mechanism of action against microbes is still not fully understood. Infections in the genitourinary system caused by Candida spp. are associated with its fungal resistance and pathogenicity. New plant-derived compounds are an alternative to fight these Candida infections. AIM OF THE STUDY: The objective of this study was to evaluate the anti-Candida effects of extracts of the stem bark of H. speciosa. This research investigated the chemical composition of sulfuric ether (EEHS) and methanolic (MEHS) extracts, their drug-modifying action on fluconazole, and their anti-virulence action on the morphological transition of Candida species. MATERIALS AND METHODS: The extracts (EEHS and MEHS) of the stem bark of H. speciosa were chemically characterized via qualitative phytochemical screening and by liquid chromatography coupled with mass spectrometry (UPLC-MS-ESI-QTOF). The extracts were evaluated regarding their antifungal effects and fluconazole-modifying activity against Candida albicans, Candida krusei, and Candida tropicalis using the broth microdilution method. Additionally, the study evaluated the inhibition of fungal virulence in Candida species through morphological transition assays. RESULTS: The phytochemical screening revealed the presence of anthocyanidins, anthocyanins, aurones, catechins, chalcones, flavones, flavonols, flavanones, leucoanthocyanidins, tannins (condensed and pyrogallic), and xanthones in both extracts of the stem bark of H. speciosa. The UPLC-MS-ESI-QTOF analysis identified the same compounds in both extracts, predominating phenolic compounds. Some compounds were first time recorded in this species: gluconic acid, cinchonain IIb, cinchonain Ib isomer, and lariciresinol hexoside isomers. Most of the intrinsic antifungal activity was observed for the MEHS against C. krusei (IC50: 58.41 µg/mL). At subinhibitory concentrations (MC/8), the EEHS enhanced the action of fluconazole against all Candida strains. The MEHS exhibited greater efficacy than fluconazole inhibiting C. krusei growth. The EEHS completely inhibited hyphae appearance and reduced pseudohyphae formation in C. albicans. CONCLUSION: The stem bark of H. speciosa is a rich source of bioactive compounds, especially phenolic. Phenolic compounds can have important roles in fighting infectious diseases of the genitourinary system, such as candidiasis. The extracts of H. speciosa improved the action of the drug fluconazole against Candida species, inhibited hyphae appearance, and reduced pseudohyphae formation. The results of this study can support the development of new therapeutics against resistant strains of Candida.

Potentiating-antibiotic activity and absorption, distribution, metabolism, excretion and toxicity properties (ADMET) analysis of synthetic thiadiazines against multi-drug resistant (MDR) strains.

BACKGROUND: Thiadiazines are heterocyclic compounds that contain two nitrogen atoms and one sulfur atom in their structure. These synthetic molecules have several relevant pharmacological activities, such as antifungal, antibacterial, and antiparasitic. OBJECTIVES: The present study aimed to evaluate the possible in vitro and in silico interactions of compounds derived from thiadiazines. METHODS: The compounds were initially synthesized, purified, and confirmed through HPLC methodology. Multi-drug resistant bacterial strains of Staphylococcus aureus 10 and Pseudomonas aeruginosa 24 were used to evaluate the direct and modifying antibiotic activity of thiadiazine derivatives. ADMET assays (absorption, distribution, metabolism, excretion, and toxicity) were conducted, which evaluated the influence of the compounds against thousands of macromolecules considered as bioactive targets. RESULTS: There were modifications in the chemical synthesis in carbon 4 or 3 in one of the aromatic rings of the structure where different ions were added, ensuring a variability of products. It was possible to observe results that indicate the possibility of these compounds acting through the cyclooxygenase 2 mechanism, which, in addition to being involved in inflammatory responses, also acts by helping sodium reabsorption. The amine group present in thiadiazine analogs confers hydrophilic characteristics to the substances, but this primary characteristic has been altered due to alterations and insertions of other ligands. The characteristics of the analogs generally allow easy intestinal absorption, reduce possible hepatic toxic effects, and enable possible neurological and anti-inflammatory action. The antibacterial activity tests showed a slight direct action, mainly of the IJ23 analog. Some compounds were able to modify the action of the antibiotics gentamicin and norfloxacin against multi-drug resistant strains, indicating a possible synergistic action. CONCLUSIONS: Among all the results obtained in the study, the relevance of thiadiazine analogs as possible coadjuvant drugs in the antibacterial, anti-inflammatory, and neurological action with low toxicity is clear. Need for further studies to verify these effects in living organisms is not ruled out.

Synthesis, spectroscopic characterization, and antibacterial activity of chalcone (2E)-1-(3'-aminophenyl)-3-(4-dimethylaminophenyl)-prop-2-en-1-one against multiresistant Staphylococcus aureus carrier of efflux pump mechanisms and ß-lactamase.

BACKGROUND: The bacterium Staphylococcus aureus has stood out for presenting a high adaptability, acquiring resistance to multiple drugs. The search for natural or synthetic compounds with antibacterial properties capable of reversing the resistance of S. aureus is the main challenge to be overcome today. Natural products such as chalcones are substances present in the secondary metabolism of plants, presenting important biological activities such as antitumor, antidiabetic, and antimicrobial activity. OBJECTIVES: In this context, the aim of this work was to synthesize the chalcone (2E)-1-(3'-aminophenyl)-3-(4-dimethylaminophenyl)-prop-2-en-1-one with nomenclature CMADMA, confirm its structure by nuclear magnetic resonance (NMR), and evaluate its antibacterial properties. METHODS: The synthesis methodology used was that of Claisen-Schmidt, and spectroscopic characterization was performed by NMR. For microbiological assays, the broth microdilution methodology was adopted in order to analyze the antibacterial potential of chalcones and to analyze their ability to act as a possible inhibitor of ß-lactamase and efflux pump resistance mechanisms, present in S. aureus strain K4100. RESULTS: The results obtained show that CMADMA does not show direct antibacterial activity, expressing a MIC of ≥1024 µg/mL, or on the enzymatic mechanism of ß-lactamase; however, when associated with ethidium bromide in efflux pump inhibition assays, CMADMA showed promising activity by reducing the MIC of the bromide from 64 to 32 µg/mL. CONCLUSION: We conclude that the chalcone synthesized in this study is a promising substance to combat bacterial resistance, possibly acting in the inhibition of the QacC efflux pump present in S. aureus strain K4100, as evidenced by the reduction in the MIC of ethidium bromide.

Synthesis, structural, characterization, antibacterial and antibiotic modifying activity, ADMET study, molecular docking and dynamics of chalcone (E)-1-(4-aminophenyl)-3-(4-nitrophenyl)prop-2-en-1-one in strains of Staphylococcus aureus carrying NorA and MepA efflux pumps.

Chalcones have an open chain flavonoid structure that can be obtained from natural sources or by synthesis and are widely distributed in fruits, vegetables, and tea. They have a simple and easy to handle structure due to the α-ß-unsaturated bridge responsible for most biological activities. The facility to synthesize chalcones combined with its efficient in combating serious bacterial infections make these compounds important agents in the fight against microorganisms. In this work, the chalcone (E)-1-(4-aminophenyl)-3-(4-nitrophenyl)prop-2-en-1-one (HDZPNB) was characterized by spectroscopy and electronic methods. In addition, microbiological tests were performed to investigate the modulator potential and efflux pump inhibition on S. aureus multi-resistant strains. The modulating effect of HDZPNB chalcone in association with the antibiotic norfloxacin, on the resistance of the S. aureus 1199 strain, resulted in increase the MIC. In addition, when HDZPNB was associated with ethidium bromide (EB), it caused an increase in the MIC value, thus not inhibiting the efflux pump. For the strain of S. aureus 1199B, carrying the NorA pump, the HDZPNB associated with norfloxacin showed no modulatory, and when the chalcone was used in association with EB, it had no inhibitory effect on the efflux pump. For the tested strain of S. aureus K2068, which carries the MepA pump, it can be observed that the chalcone together the antibiotic resulted in an increase the MIC. On the other hand, when chalcone was used in association with EB, it caused a decrease in bromide MIC, equal to the reduction caused by standard inhibitors. Thus, these results indicate that the HDZPNB could also act as an inhibitor of the S. aureus gene overexpressing pump MepA. The molecular docking reveals that chalcone has a good binding energies -7.9 for HDZPNB/MepA complexes, molecular dynamics simulations showed that Chalcone/MetA complexes showed good stability of the structure in an aqueous solution, and ADMET study showed that the chalcone has a good oral bioavailability, high passive permeability, low risk of efflux, low clearance rate and low toxic risk by ingestion. The microbiological tests show that the chalcone can be used as a possible inhibitor of the Mep A efflux pump.Communicated by Ramaswamy H. Sarma.

Assessment of Quercetin Antiemetic Properties: In Vivo and In Silico Investigations on Receptor Binding Affinity and Synergistic Effects.

Quercetin (QUA), a flavonoid compound, is ubiquitously found in plants and has demonstrated a diverse range of biological activities. The primary objective of the current study is to assess the potential antiemetic properties of QUA using an in vivo and in silico approach. In this experiment, 4-day-old chicks were purchased to induce emesis by orally administering copper sulfate pentahydrate (CuSO4·5H2O) at a dose of 50 mg/kg (orally). Domperidone (DOM) (6 mg/kg), Hyoscine (HYS) (21 mg/kg), and Ondansetron (OND) (5 mg/kg) were treated as positive controls (PCs), and distilled water and a trace amount of Tween 80 mixture was employed as a negative control (NC). QUA was given orally at two distinct doses (25 and 50 mg/kg). Additionally, QUA (50 mg/kg) and PCs were administered separately or in combination to assess their antagonistic or synergistic effects on the chicks. The binding affinity of QUA and referral ligands towards the serotonin receptor (5HT3), dopamine receptors (D2 and D3), and muscarinic acetylcholine receptors (M1-M5) were estimated, and ligand-receptor interactions were visualized through various computational tools. In vivo findings indicate that QUA (25 and 50 mg/kg) has a significant effect on reducing the number of retches (16.50 ± 4.65 and 10.00 ± 4.19 times) and increasing the chick latency period (59.25 ± 4.75 and 94.25 ± 4.01 s), respectively. Additionally, QUA (50 mg/kg) in combination with Domperidone and Ondansetron exhibited superior antiemetic effects, reducing the number of retches and increasing the onset of emesis-inducing time. Furthermore, it is worth noting that QUA exhibited the strongest binding affinity against the D2 receptor with a value of -9.7 kcal/mol through the formation of hydrogen and hydrophobic bonds. In summary, the study found that QUA exhibited antiemetic activity in chicks, potentially by interacting with the D2 receptor pathway.

Comparative Antibacterial and Efflux Pump Inhibitory Activity of Isolated Nerolidol, Farnesol, and α-Bisabolol Sesquiterpenes and Their Liposomal Nanoformulations.

The efflux systems are considered important mechanisms of bacterial resistance due to their ability to extrude various antibiotics. Several naturally occurring compounds, such as sesquiterpenes, have demonstrated antibacterial activity and the ability to inhibit efflux pumps in resistant strains. Therefore, the objective of this research was to analyze the antibacterial and inhibitory activity of the efflux systems NorA, Tet(K), MsrA, and MepA by sesquiterpenes nerolidol, farnesol, and α-bisabolol, used either individually or in liposomal nanoformulation, against multi-resistant Staphylococcus aureus strains. The methodology consisted of in vitro testing of the ability of sesquiterpenes to reduce the Minimum Inhibitory Concentration (MIC) and enhance the action of antibiotics and ethidium bromide (EtBr) in broth microdilution assays. The following strains were used: S. aureus 1199B carrying the NorA efflux pump, resistant to norfloxacin; IS-58 strain carrying Tet(K), resistant to tetracyclines; RN4220 carrying MsrA, conferring resistance to erythromycin. For the EtBr fluorescence measurement test, K2068 carrying MepA was used. It was observed the individual sesquiterpenes exhibited better antibacterial activity as well as efflux pump inhibition. Farnesol showed the lowest MIC of 16.5 µg/mL against the S. aureus RN4220 strain. Isolated nerolidol stood out for reducing the MIC of EtBr to 5 µg/mL in the 1199B strain, yielding better results than the positive control CCCP, indicating strong evidence of NorA inhibition. The liposome formulations did not show promising results, except for liposome/farnesol, which reduced the MIC of EtBr against 1199B and RN4220. Further research is needed to evaluate the mechanisms of action involved in the inhibition of resistance mechanisms by the tested compounds.

Investigation of mechanisms of action involved in the antidepressant-like effect of Trans,trans-farnesol in mice.

This study aimed to investigate, through in vivo and biochemical methodologies, the effect of trans,trans-farnesol (12.5, 25, 50 or 100 mg/kg, p.o.) acute administration, adopting different behavioral and neurochemical parameters associated with an acute induced-depression model in mice. The initial results showed that, the oral treatment with trans,trans-farnesol, at the dose of 100 mg/kg induced a possible antidepressant-like effect in animals subjected to forced swim test (FST) and reserpine-induced akinesia. In addition, it was observed that the compound in question has an effect size and properties similar to imipramine (prototype of tricyclic antidepressants), but devoid of proconvulsant adverse effect. In biochemical assays, the pretreatment with trans,trans-farnesol, at a dose of 100 mg/kg (p.o.), decreased the hippocampal concentration of thiobarbituric acid reactive substances (TBARS) and restored striatal levels of noradrenaline and serotonin in mice subjected to FST. Altogether, these results suggest that trans,trans-farnesol showed a significant antidepressant-like effect, which seems to be mediated by the antagonism of muscarinic cholinergic receptors, reduction of oxidative stress and the modulation of noradrenaline and serotonin content in the central nervous system.

Valencene, Nootkatone and Their Liposomal Nanoformulations as Potential Inhibitors of NorA, Tet(K), MsrA, and MepA Efflux Pumps in Staphylococcus aureus Strains.

Valencene and nootkatone are aromatic sesquiterpenes with known biological activities, such as antimicrobial, antioxidant, anti-inflammatory, and antitumor. Given the evidence that encapsulation into nanosystems, such as liposomes, could improve the properties of several compounds, the present study aimed to evaluate the activity of these sesquiterpenes in their isolated state or in liposomal formulations against strains of Staphylococcus aureus carrying efflux pumps. The broth microdilution method evaluated the antibiotic-enhancing activity associated with antibiotics and ethidium bromide (EtBr). The minimum inhibitory concentration was assessed in strains of S. aureus 1199B, IS-58, and RN4220, which carry the efflux proteins NorA, Tet(K), and MsrA. In tests with strain 1199B, valencene reduced the MIC of norfloxacin and EtBr by 50%, while the liposomal formulation of this compound did not show a significant effect. Regarding the strain IS-58, valencene, and its nanoformulation reduced norfloxacin MIC by 60.3% and 50%, respectively. In the non-liposomal form, the sesquiterpene reduced the MIC of EtBr by 90%. Against the RN4220 strain, valencene reduced the MIC of the antibiotic and EtBr by 99% and 93.7%, respectively. Nootkatone and its nanoformulation showed significant activity against the 1199B strain, reducing the EtBr MIC by 21.9%. Against the IS-58 strain, isolated nootkatone reduced the EtBr MIC by 20%. The results indicate that valencene and nootkatone potentiate the action of antibiotics and efflux inhibitors in strains carrying NorA, Tet(K), and MsrA proteins, which suggests that these sesquiterpenes act as efflux pump inhibitors in S. aureus. Therefore, further studies are needed to assess the impact of incorporation into liposomes on the activity of these compounds in vivo.

Biochemical aspects of the inflammatory process: A narrative review.

Inflammation is a protective response of the body potentially caused by microbial, viral, or fungal infections, tissue damage, or even autoimmune reactions. The cardinal signs of inflammation are consequences of immunological, biochemical, and physiological changes that trigger the release of pro-inflammatory chemical mediators at the local of the injured site thus, increasing blood flow, vascular permeability, and leukocyte recruitment. The aim of this study is to give an overview of the inflammatory process, focusing on chemical mediators. The literature review was based on a search of journals published between the years 2009 and 2023, regarding the role of major chemical mediators in the inflammatory process and current studies in pathogenesis, diagnosis, and therapy. Some of the recent contributions in the study of inflammatory pathologies and their mediators, including cytokines and chemokines, the kinin system, free radicals, nitric oxide, histamine, cell adhesion molecules, leukotrienes, prostaglandins and the complement system and their role in human health and chronic diseases.

Antiemetic effects of sclareol, possibly through 5-HT3 and D2 receptor interaction pathways: In-vivo and in-silico studies.

BACKGROUND: Emesis is a complex physiological phenomenon that serves as a defense against numerous toxins, stressful situations, adverse medication responses, chemotherapy, and movement. Nevertheless, preventing emesis during chemotherapy or other situations is a significant issue for researchers. Hence, the majority view contends that successfully combining therapy is the best course of action. In-vivo analysis offers a more comprehensive grasp of how compounds behave within a complex biological environment, whereas in-silico evaluation refers to the use of computational models to forecast biological interactions. OBJECTIVES: The objectives of the present study were to evaluate the effects of Sclareol (SCL) on copper sulphate-induced emetic chicks and to investigate the combined effects of these compounds using a conventional co-treatment approach and in-silico study. METHODS: SCL (5, 10, and 15 mg/kg) administered orally with or without pre-treatment with anti-emetic drugs (Ondansetron (ODN): 24 mg/kg, Domperidone (DOM): 80 mg/kg, Hyoscine butylbromide (HYS): 100 mg/kg, and Promethazine hydrochloride (PRO): 100 mg/kg) to illustrate the effects and the potential involvement with 5HT3, D2, M3/AChM, H1, or NK1 receptors by SCL. Furthermore, an in-silico analysis was conducted to forecast the role of these receptors in the emetic process. RESULTS: The results suggest that SCL exerted a dose-dependent anti-emetic effect on the chicks. Pretreatment with SCL-10 significantly minimized the number of retches and lengthened the emesis tendency of the experimental animals. SCL-10 significantly increased the anti-emetic effects of ODN and DOM. However, compared to the ODN-treated group, (SCL-10 + ODN) group considerably (p < 0.0001) extended the latency duration (109.40 ± 1.03 s) and significantly (p < 0.01) decreased the number of retches (20.00 ± 0.70), indicating an anti-emetic effect on the test animals. In in-silico analysis, SCL exhibited promising binding affinities with suggesting receptors. CONCLUSION: SCL-10 exerted an inhibitory-like effect on emetic chicks, probably through the interaction of the 5HT3 and D2 receptors. Further studies are highly appreciated to validate this study and determine the precise mechanism(s) behind the anti-emetic effects of SCL. We expect that SCL-10 may be utilized as an antiemetic treatment in a single dosage form or that it may function as a synergist with other traditional medicines.

Sclareol exerts synergistic antidepressant effects with quercetin and caffeine, possibly suppressing GABAergic transmission in chicks.

This study evaluated the effects of sclareol (SCL) with or without caffeine (CAF) and quercetin (QUR) using in-vivo and in-silico studies. For this, 5-day-old chicks weighing between 45 and 48 g were randomly divided into five groups and treated accordingly. The chicks were monitored to compare the occurrence, latency, and duration of sleep as well as the loss and gain of righting reflex in response to SCL-10 mg/kg, CAF-10 mg/kg, and QUR-50 mg/kg using a thiopental sodium (TS)-induced sleeping model. Data were analyzed by one-way ANOVA followed by t-Student-Newman-Keuls' as a posthoc test at 95% confidence intervals with multiple comparisons. An in-silico study was also performed to investigate the possible antidepressant mechanisms of the test and/or standard drugs with different subunits of GABAA receptors. In comparison to the SCL, CAF, and QUR individual groups, SCL+CAF+QUR significantly increased the latency while decreasing the length of sleep. The incidence of loss and gain of the righting reflex was also modulated in the combination group. SCL showed better interaction with GABAA (α2 and α5) subunits than QUR with α2, α3, and α5. All these compounds showed stronger interactions with the GABAA receptor subunits than the standard CAF. Taken together, SCL, CAF, and QUR reduced the TS-induced righting reflex and sleeping time in the combination group more than in the individual treatments. SCL may show its antidepressant effects, possibly through interactions with GABAA receptor subunits.

Antiedematogenic and Analgesic Activities of Abietic Acid in Mice.

Exacerbated inflammatory responses to harmful stimuli can lead to significant pain, edema, and other complications that require pharmacological intervention. Abietic acid (AA) is a diterpene found as a significant constituent in pine species, and evidence has identified its biological potential. The present study aimed to evaluate abietic acid's antiedematogenic and anti-inflammatory activity in mice. Swiss mice (Mus musculus) weighing 20-30 g were treated with AA at 50, 100, and 200 mg/kg. The central nervous system (CNS) effects were evaluated using open-field and rotarod assays. The antinociceptive and anti-inflammatory screening was assessed by the acetic acid and formalin tests. The antiedematogenic activity was investigated by measuring paw edema induced by carrageenan, dextran, histamine, arachidonic acid, and prostaglandin, in addition to using a granuloma model. The oral administration of abietic acid (200 mg/Kg) showed no evidence of CNS effects. The compound also exhibited significant antiedematogenic and anti-inflammatory activities in the carrageenan and dextran models, mostly related to the inhibition of myeloperoxidase (MOP) activity and histamine action and, to a lesser extent, the inhibition of eicosanoid-dependent pathways. In the granuloma model, abietic acid's effect was less expressive than in the acute models investigated in this study. In conclusion, abietic acid has analgesic and antiedematogenic activities related to anti-inflammatory mechanisms.

Chemical composition and antibacterial effects of Etlingera elatior (Jack) R.M. Smith against Staphylococcus aureus efflux pumps.

Multidrug resistance is a significant health problem worldwide, with increasing mortality rates, especially in the last few years. In this context, a consistent effort has been made to discover new antibacterial agents, and evidence points to natural products as the most promising source of bioactive compounds. This research aimed to characterize the antibacterial effect of the essential oil of Etlingera elatior (EOEE) and its major constituents against efflux pump-carrying Staphylococcus aureus strains. The essential oil was extracted from fresh inflorescences by hydrodistillation. Chemical analysis was performed using gas chromatography coupled to mass spectrometry (GC-MS) and gas chromatography equipped with a flame ionization detector (GC-FID). The strains RN-4220, 1199B, IS-58, and 1199 of S. aureus were used to evaluate the antibacterial activity and the inhibition of efflux pumps. A total of 23 compounds were identified, including dodecanal and 1-dodecanol as major compounds. EOEE and dodecanal showed weak activity against the strains, while 1-dodecanol inhibited bacterial growth at low concentrations, indicating strong antibacterial activity. In addition, this compound potentiated the activity of norfloxacin against S. aureus 1199. In conclusion, 1-dodecanol was identified as the most effective compound of EOEE, showing significant potential to be used in antibacterial drug development.

Inhibition of the norA gene expression and the NorA efflux pump by the tannic acid.

The NorA efflux pump of Staphylococcus aureus is known to play a major role in the development of resistance against quinolone drugs by reducing their concentration inside target pathogens. The objective of this study was to evaluate the ability of tannic acid to inhibit the gene expression of the NorA efflux pump in Staphylococcus aureus and to evaluate the in silico effect on the pump. Efflux pump inhibition was evaluated by fluorimetry. The checkerboard method evaluates the effect of the test substance in combination with an antimicrobial at different concentrations. To gene expression evaluation NorA the assay was performed using: a sub-inhibitory concentration preparation (MIC/4) of the antibiotic; a sub-inhibitory concentration preparation (MIC/4) of the antibiotic associated with tannic acid at a sub-inhibitory concentration (MIC/4). In this study, docking simulations were performed by the SWISSDOCK webserver. The ability of tannic acid to inhibit the NorA efflux pump can be related to both the ability to inhibit the gene expression of this protein, acting on signaling pathways involving the ArlRS membrane sensor. As well as acting directly through direct interaction with the NorA protein, as seen in the approach and in silico and in vitro per checkerboard method and fluorimetry of bromide accumulated in the cell.