Minimum Bactericidal Concentration Values Research Articles

Antimicrobial activity of Cinnamomum zeylanicum essential oil against colistin-resistant gram-negative bacteria

ABSTRACT In the current study, we evaluated the antimicrobial activity of Cinnamomum zeylanicum Blume essential oil (Cinn-EO) against a group of thirteen clinical colistin-resistant Gram-negative bacteria, including Escherichia coli, Klebsiella pneumoniae, and Pseudomonas aeruginosa. The GCMS analysis showed that cinnamaldehyde was the major compound (94.29%) of the Cinn-EO. The diameter of the inhibition zone by Cinn-EO varied from 24 to 37 mm. The minimum inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) values ranged between 0.625 and 5 mg/mL. Interestingly, the MBC/MIC was equal to 1 for most tested bacterial strains, indicating an advanced bactericidal effect of Cinn-EO against colistin-resistant Gram-negative bacteria. The absorption, distribution, metabolism, elimination, and toxicity (ADMET) prediction showed good pharmacokinetic properties of the tested cinnamaldehyde. The results suggest that cinnamaldehyde could be a potential alternative to treat infection caused by colistin-resistant Gram-negative bacteria.

Influence of low-cost Thai leucoxene minerals on the growth, bioactive compounds, and antibacterial activities of Chrysanthemum indium L. cuttings in in vitro culture

The effects of low-cost Thai leucoxene mineral (LM) at different concentrations (10, 20, 30, 40, 50, and 60 mg/L) on the growth and antibacterial properties of Chrysanthemum indium L. cuttings under in vitro were evaluated. The primary chemical composition of LM was approximately 86% titanium dioxide (TiO2), as determined by dispersive X-ray spectroscopy. The crystalline structure, shape, and size were investigated by X-ray diffraction and scanning electron microscopy. LM at 40 and 50 mg/L significantly increased plant height, leaf number, node number, and fresh and dry weight. These growth-promoting properties were accompanied by improved chlorophyll and carotenoid contents and antioxidant enzyme activities and reduced malondialdehyde levels. Additionally, LM treatment at 40 and 50 mg/L had positive effects on antibacterial activity, as indicated by the lowest minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) values. The high levels of phenolic compounds in the plants contributed to the MIC and MBC values. In conclusion, these findings provide evidence for the effectiveness of LM in enhancing the growth of Chrysanthemum plants in in vitro culture and improving their antibacterial abilities.

Synergistic Potential Sof Cinnamon Extracts, Antibiotics, and Alum on Selected Clinical Microbes

Antibiotics are natural or synthetic substances used to inhibit or kill susceptible microorganisms. Due to the increase rate of bacterial resistance to antibiotics, there is the need to venture in other methods involving the coalescence effect of antibiotics and other substances such as cinnamon and alum to effectively eradicate these pathogenic organisms using less concentrated conventional antibiotics. The minimum inhibitory concentration (MIC) and the minimum bactericidal concentration (MBC) of the selected antimicrobial agents were determined using the broth dilution method, following standards and procedures set by the national council of clinical laboratory standards (NCCLS). The synergistic potentials of all the antimicrobics used were analyzed by the checkerboard assay. The MIC values of 25, 0.25, 0.75,25mg/ml were obtained for cinnamon extracts, gentamicin, penicillin G, and aq. Alum respectively against S. aureus. For E. coli O157H:H7, the MIC values of cinnamon extracts, gentamicin, penicillin G, and aq. Alum were 12.5, 0.25, 0.75 and 25mg/ml respectively,s while the MIC values of cinnamon extracts alum and fluconazole for C. albicans were 12.5, 25 and 0.05mg/ml respectively. There is a reduction in the MIC values for the various combinations against the same clinical microbes. All the antimicrobics used in this study inhibited the growth of the clinical microbes. All the microbes used in this study inhibited the tested microbes in dose dependent manner. The combinations of these agents resulted in reduction in MIC and MBC values, with an additive, indifference, and antagonistic effects using checkerboard assay which resulted to a fractional inhibitory concentration index which ranged from 0.56 to 7.9. Therefore, application of cinnamon, alum, and their combinations with conventional antibiotics can be used as treatment measure against infections caused by S. aureus, E. coli O157H:H7, and C. albicans.

UJI EFEKTIVITAS ANTIBAKTERI EKSTRAK DAUN RAMANIA (Bouea Macrophylla Griff) TERHADAP PERTUMBUHAN BAKTERI Streptococcus mitis

Background: The presence of cavities causes bacterial invasion and spread of infection to the pulp tissue. If left untreated, infection will lead to pulpal necrosis. Root canal treatment can prevent caries from developing into necrosis. The success of treatment is influenced by the preparation and irrigation stages. One of the bacteria that survived after the treatment was Streptococcus mitis. The irrigation solution used in treatment is a 2% chlorhexidine gluconate. Ethanol extract from Ramania leaves is known to contain flavonoids, phenols, alkaloids, steroids and terpenoids which proven to have antibacterial activity. Objective: To analyze the antibacterial effectiveness of Ramania leaf extract  concentrations of 10%, 15%, 20%, 25% and 30% against the growth of Streptococcus mitis . Methods: The research conducted was a true experimental study with 6 treatment groups and 4 repetitions. This study used broth and agar dilution methods to determine the minimum inhibitory concentration (MIC) and the minimum bactericidal concentration (MBC) of ramania leaf extract against Streptococcus mitis. Results: The MIC was shown by 10% concentration with a decrease in absorbance value of 1.726. The MBC in this study were not found because there was still bacterial growth in the concentrations of 10%, 15%, 20%, 25% and 30%. Conclusion: Ramania leaf extract concentrations of 10%, 15%, 20%, 25% and 30% can inhibit the growth of Streptococcus mitis with MIC value at a concentration of 10%. The MBC value was not found because the extract had not been able to kill the growth of Streptococcus mitis. Keywords : MBC,  MIC, Ramania Leaf Extract, Streptococcus mitis

Synthesis and characterization of antimicrobial colloidal polyanilines

The potential application of colloidal polyaniline (PANI) as an antimicrobial is limited by challenges related to solubility in common organic solvents, scalability, and antimicrobial potency. To address these limitations, we introduced a functionalized PANI (fPANI) with carboxyl groups through the polymerisation of aniline and 3-aminobenzoic acid in a 1:1 molar ratio. fPANI is more soluble than PANI which was determined using a qualitative study. We further enhanced the solubility and antimicrobial activity of fPANI by incorporating Ag nanoparticles onto the synthesized fPANI colloid via direct addition of 10mM AgNO3. The improved solubility can be attributed to an approximately 3-fold reduction in size of particles. Mean particle sizes are measured at 1322nm for fPANI colloid and 473nm for fPANI-Ag colloid, showing a high dispersion and deagglomeration effect from Ag nanoparticles. Antimicrobial tests demonstrated that fPANI-Ag colloids exhibited superior potency against Gram-positive Staphylococcus aureus, Gram-negative Escherichia coli, and Bacteriophage PhiX 174 when compared to fPANI alone. The minimum bactericidal concentration (MBC) and minimum virucidal concentration (MVC) values were halved for fPANI-Ag compared to fPANI colloid and attributed to the combination of Ag nanoparticles with the fPANI polymer. The antimicrobial fPANI-Ag colloid presented in this study shows promising results, and further exploration into scale-up can be pursued for potential biomedical applications.

Simultaneous effect of medicinal plants as natural photosensitizers and low-level laser on photodynamic inactivation.

Photodynamic inactivation (PDI) technology is a promising alternative to antibiotics. This technology is defined as the inhibition of bacterial growth with photosensitizers while irradiated with low-level laser light in the wavelength of 532 ± 2.08nm. A challenging area in this field is selecting photosensitizers with antibacterial potential. In this paper, to enhance the antibacterial efficiency, the photosensitizers (the selected plant extracts) with a high absorption peak at the selected laser frequency, 532nm, were prepared. Low-concentration ethanolic plant extracts of Hibiscus sabdariffa and Opuntia ficus-indica were found to exhibit significant antibacterial activity against, Acinetobacter baumannii ATCC 19606 and, Staphylococcus aureus ATCC 33591 as two important human pathogenic bacteria. The effectiveness of these natural photosensitizers was measured by determining their Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) values and by performing a time-killing assay in the absence and the presence of laser irradiation. Our results showed that the combination of low-level laser irradiation and the selected photosensitizers had excellent potential for treating in vitro bacterial infections. Therefore, PDI technology has great potential as a viable alternative to traditional antibiotics for combating bacterial infections. This study presents a promising avenue for further exploration of PDI and the use of laser technology in medical science.

Phytochemical characterization and biological activities evaluation of Opuntia sp. cladodes

The prickly pear is a plant belonging to the Cactaceae family, and it is the best-known species that has gained significant recognition in recent years. Opuntia sp. cladodes have been traditionally utilized as a functional food and in traditional medicine for treating chronic diseases. Therefore, this study aims to evaluate the antioxidant, antimicrobial, and pharmacological activities of cladode extracts from Opuntia microdasys (Cl1) and Opuntia macrorhiza (Cl2), as well as to identify their phytochemical compounds. The chemical composition of the cladode extracts was analyzed using spectrophotometric methods, while the antioxidant activity was determined through DNA nicking assays. Microdilution assays were employed to assess the antimicrobial activity. Analgesic and anti-inflammatory activities were determined using the acetic acid writhing test in mice and the carrageenan-induced Wistar rat paw edema test. The results revealed that the two extracts of cladodes from Cl1 and Cl2 were characterized by a high phenolic content (58.13 and 44.58 GAE/g of extract, respectively). All the tested extracts exhibited antimicrobial activity against the strains tested, with Minimum Inhibitory Concentration (MIC) values ranging from 0.312 to 5 mg/mL and Minimum Bactericidal Concentration (MBC) values ranging from 1.25 to 10 mg/mL. The cladode extracts of Cl1 and Cl2 at a dose of 300 mg/kg showed a dose-dependent inhibition of acetic acid-induced writhing in mice, with respective values of 64.76 % and 61.91 %. The maximum anti-inflammatory activity of all doses of cladode extracts was observed 5 h after carrageenan-induced paw edema, and all tested doses significantly inhibited the induced inflammation.

Aktivitas Antibakteri dan Antioksidan dari Senyawa Bioaktif Asal Bakteri Endofit Tanaman Nyatoh (Palaquium amboinense B.)

Nyatoh plant (Palaquium amboinense B.) is native to Indonesia which is known to have the ability to produce potential secondary metabolites. The aim of this study was to evaluate the antibacterial and antioxidant activities from bioactive compounds produced by endophytic bacteria from nyatoh leaves. Five endophytic bacteria were tested against 4 targeted bacteria including Escherichia coli ATCC 8739, Pseudomonas aeruginosa ATCC 15442, Bacillus subtilis ATCC 19659, and Staphylococcus aureus ATCC 6538. Bacterial isolate which had the strongest antibacterial activity was then fermented and extracted. The corresponding extract was further tested on disc diffusion method, determination of Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) values, antioxidant evaluation, and analyzed for its bioactive compound components via GC-MS analysis. The results showed that one isolate, namely D1 can produce secondary metabolite which act as antibacterial and antioxidant potentials. This corresponding extract has the strongest MIC and MBC against B. subtilis with value of 39.5 and >78.1 µg/ml and exhibited antioxidant activity against 2,2-difenil-1-pikrilhidrazil (DPPH) with inhibition value of 85.37%. Based on GC-MS analysis, secondary metabolites derived from this potential extract contained some major active constituents including Tributyl acetylcitrate and bis (2-ethylhexyl) ester which might act as antibacterial and antioxidant agents.

Valorization of sesame (Sesamum indicum L.) seed coats: Optimization of polyphenols’ extraction using Ired-Irrad® and assessment of their biological activities

Sesame (Sesamum indicum L.) seed coat (SSC) is a by-product generated during the production of sesame paste, known as tahini. Research has demonstrated that this by-product is abundant in valuable nutritional compounds. Various extraction methods are employed to enhance the value of industrial waste by recovering its bioactive compounds. The study aims to optimize the extraction of polyphenols utilizing an infrared technique Ired-Irrad® (IR), in comparison to the water bath (WB) extraction. To optimize the extraction of polyphenols from SSC using both the IR and WB extraction methods, the study utilized Response Surface Methodology (RSM). Under optimal conditions, IR extraction resulted in an improved polyphenol yield, which was 20% higher than that obtained using WB extraction. Similarly, the antiradical activity, quantified as mg of Trolox equivalent per milliliter, increased from 0.58 mg TE/mL in the WB extract to 0.68 mg TE/mL in the IR extract. The phytochemical profile of the IR and WB extracts was examined through High-Performance Liquid Chromatography (HPLC). The major polyphenols identified in both extracts were the flavonoids rutin (3.87 mg/L in IR, 1.72 mg/L in WB) and catechin (3.05 mg/L in IR, 1.32 mg/L in WB). The IR extract revealed the highest yield of polyphenols among the majority of compounds, compared to WB. The lyophilized SSC extracts obtained through both the IR and WB methods demonstrated the most effective antibacterial activity against Listeria monocytogenes, with a minimal bactericidal concentration (MBC) value exceeding 100 mg/mL. However, minor antibacterial effects were detected against the Gram-negative strains, Salmonella Typhimurium and Escherichia coli O157:H7, for extracts obtained with both the IR and WB methods.

Oxidative Stress-Mediated Repression of Virulence Gene Transcription and Biofilm Formation as Antibacterial Action of Cinnamomum burmannii Essential Oil on Staphylococcus aureus.

This work aimed to identify the chemical compounds of Cinnamomum burmannii leaf essential oil (CBLEO) and to unravel the antibacterial mechanism of CBLEO at the molecular level for developing antimicrobials. CBLEO had 37 volatile compounds with abundant borneol (28.40%) and showed good potential to control foodborne pathogens, of which Staphylococcus aureus had the greatest inhibition zone diameter (28.72 mm) with the lowest values of minimum inhibitory concentration (1.0 μg/mL) and bactericidal concentration (2.0 μg/mL). To unravel the antibacterial action of CBLEO on S. aureus, a dynamic exploration of antibacterial growth, material leakage, ROS formation, protein oxidation, cell morphology, and interaction with genome DNA was conducted on S. aureus exposed to CBLEO at different doses (1/2-2×MIC) and times (0-24 h), indicating that CBLEO acts as an inducer for ROS production and the oxidative stress of S. aureus. To highlight the antibacterial action of CBLEO on S. aureus at the molecular level, we performed a comparative association of ROS accumulation with some key virulence-related gene (sigB/agrA/sarA/icaA/cidA/rsbU) transcription, protease production, and biofilm formation in S. aureus subjected to CBLEO at different levels and times, revealing that CBLEO-induced oxidative stress caused transcript suppression of virulence regulators (RsbU and SigB) and its targeted genes, causing a protease level increase destined for the biofilm formation and growth inhibition of S. aureus, which may be a key bactericidal action. Our findings provide valuable information for studying the antibacterial mechanism of essential oil against pathogens.

Volatile compounds and bioactivities properties of Opuntia microdasys (Lehm.) and Opuntia macrorhiza (Engelm.) seeds

The seeds of Opuntia sp. require additional investigations because they could contain several active molecules. Therefore, the present study analyzed the chemical composition and biological activities of Opuntia microdasys and that of Opuntia macrorhiza using in vitro and in vivo models.  The headspace of the powders of the seeds of Opuntia have been analyzed by gas chromatography–mass spectrometry (GC–MS). The analgesic activity was assessed using the acetic acid-induced abdominal constriction response on mouse. Chemical analyses showed that the powders of the seeds of O. microdasys and O. macrorhiza were rich in nonanal and camphor. Also, the O. macrorhiza seeds has a high antioxidant activity (EC50 =0.12 mg/ml). The results showed that the ethanolic extracts, at a dose of 200 mg/kg of body weight, caused a significant (P< 0.05) inhibition of the abdominal constriction response (75.17% and 56.22% for O. microdasys and O. microdasys). The microdilution assay revealed that ethanolic extract of O. macrorhiza seeds is more active and could inhibit the growth of almost all the evaluated bacterial and fungal strains, with the minimal bactericidal concentration values (MIC) ranging from 0.039 to 2.50 mg/mL. The overall results highlighted the potential of the tested Opuntia seeds that can be used as a source of bioactive compounds that confer various important biological activities to it, which could imply other pharmacological applications.

Physicochemical properties and biological activities of new berberine-based salts with syringic acid as well as 3,5-dimethoxybenzoic acid as anions: Effect of temperature, concentration and anion

Two novel berberine-based salts (berberine syringate ([BBR][SA]) and berberine 3,5-dimethoxybenzote ([BBR][DA])) were prepared and characterized. Their thermal stability, solubility and octanol–water partition coefficient in aqueous solution and simulated physiological fluids (simulated gastric, simulated body, simulated intestinal fluids) were determined. Self-aggregation and association behaviors of two salts in aqueous solution have been investigated by conductimetric method at different temperatures and limiting molar conductivity, critical aggregation concentration, etc for [BBR][SA] and [BBR][DA] were calculated. The minimum inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) values of two salts were assessed to evaluate their antibacterial effects on four strains (Staphylococcus aureus, Bacillus subtilis, Candida albicans, and Streptococcus mutans). The effect of two synthetic salts on the esterase-like activity of BSA and their cytotoxicity evaluation against B16-F10 cancer cell line were also carried out. The obtained results were evaluated with regard to the influence of such parameters as temperature, concentration and the nature of the anion.

ANTIBACTERIAL EFFECTIVENESS TEST OF KECAPI LEAVES EXTRACTS (Sandoricum koetjape) AGAINST THE GROWTH OF Porphyromonas gingivalis

Background: Chronic periodontitis is a disease of the oral cavity that is influenced by the presence of plaque bacteria caused by Porphyromonas gingivalis which can cause chronic infection of the periodontal tissue. Kecapi leaf (Sandoricum koetjape) extract contains active compounds in the form of flavonoids, saponins, alkaloids, steroids, phenolics, and triterpenoids which function as antibacterial against the growth of Porphyromonas gingivalis. Kecapi leaf extract is used as an alternative to using herbal gluconate to prevent infection caused of Porphyromonas gingivalis. Purpose: To determine the antibacterial effectiveness of kecapi leaf extract against bacterial growth of Porphyromonas gingivalis. Methods: This study used a pure experimental research (true experimental) with post-test only with control design, consists of 7 treatment groups, including: concentrated kecapi leaf extract 5%, 10%, 15%, 25%, 50%, chlorhexidine gluconate 0.2% as positive control, and distilled water as negative control. It was repeated 7 times, the antibacterial effectiveness was assessed from Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) on BHIB and NA media by dilution method. Results: MIC on kecapi leaf extract at a concentration of 5% showed the smallest result of -0.147 and the MBC value at a concentration of 50% did not show the growth of bacterial colonies. Conclusion: Kecapi leaf extract with concentrations of 5%, 10%, 15%, 25%, 50%, and positive control was effective in inhibiting and killing bacterial growth of Porphyromonas gingivalis. Keywords: Antibacterial, Kecapi leaf extract, Porphyromonas gingivalis

Comparison of the Antibacterial Activity of Selected Deep Eutectic Solvents (DESs) and Deep Eutectic Solvents Comprising Organic Acids (OA-DESs) Toward Gram-Positive and Gram-Negative Species.

Deep eutectic solvents (DESs) have been intensively investigated in recent years for their antibacterial properties, with DESs that comprise organic acids (OA-DESs) showing promising antibacterial action. However a majority of the reports focused only on a limited number strains and techniques, which is not enough to determine the antibacterial potential of a substance. To bridge this gap, the antibacterial activity of classical DESs and OA-DESs is assessed on twelve Gram-negative and Gram-positive bacteria strains, with some of them exhibiting specific resistance toward antibiotics. The investigated formulations of OA-DESs comprise glycolic, malic, malonic, and oxalic acids as representatives of this group. Using a range of microbiological assays as well as physicochemical characterization methods, a major difference of the effectiveness between the two groups is demonstrated, with OA-DESs exhibiting, as expected, greater antibacterial effectiveness than classical DESs. Most interestingly, slight differences in the minimum inhibitory and bactericidal concentration values as well as time-kill kinetics profiles are observed between Gram-positive and Gram-negative strains. Transmission electron microscopy analysis reveals the effect of the treatment of the bacteria with the representatives of both groups of DESs, which allows us to better understand the possible mechanism-of-action of these novel materials.

New Insights into Cutaneous Asepsis: Synergism between Pfaffia and Rosemary Extracts.

(1) Background: In hospitals, medical and dental clinics, antiseptics or disinfectants play an essential role in the control of nosocomial infections. This study aimed to evaluate R. officinalis and P. paniculata glycolic extracts regarding: (I) their antimicrobial action on planktonic and biofilm (monotypic and cutaneous biofilm model-S. aureus, S. epidermidis and C. acnes); and (II) their cytotoxicity on human keratinocytes (HaCaT). (2) Methods: Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were performed (CLSI protocol M7-A6 and M11-A8). MTT analysis was used to evaluate the antibiofilm activity of the extracts on biofilms and their cytotoxicity on human keratinocytes. (3) Results: The combined glycolic extracts MIX A (75% P. paniculata + 25% R. officinalis); MIX B (50% P. paniculata + 50% R. officinalis); and MIX C (25% P. paniculata + 75% R. officinalis) promoted MBC values by 50 mg/mL on S. aureus, absent on S. epidermidis, and ranged 6.25-50 mg/mL for C. acnes. The cutaneous biofilm model was reduced more than 90%. In addition, it showed biocompatibility with human keratinocytes, resulting in percentages of viability greater than 50%. (4) Conclusions: The combination of extracts promoted antimicrobial action on planktonic cultures, and monotypic and heterotypic biofilms of skin pathogens. Additionally, these extracts are biocompatible against human keratinocytes.

Study on synergistic effects of curcumin and bixin against foodborne pathogens.

Various studies have shown that natural colorants, in addition to their coloring attributes, have valuable biological effects such as antioxidant, anti-inflammation, and anticarcinogenic properties. Moreover, their use as a food colorant can restrict the potential disadvantages of synthetic additives and turn foods into functional products. In this study, invitro antimicrobial activities of two natural colorants of bixin and curcumin against some important foodborne pathogens: Staphylococcus aureus (S. aureus), Listeria innocua (L. innocua), and Escherichia coli (E. coli) were investigated by disk diffusion method. Minimum inhibitory concentration and minimum bactericidal concentration values were determined by agar dilution and broth microdilution methods. The synergistic activity of the colorants against selected microorganisms was assayed by the checkerboard microdilution method. The results showed that the inhibitory effects of bixin against S. aureus were more pronounced than E. coli and L. innocua. The lowest concentration of curcumin (0.6 mg/mL) in the disk diffusion method was not inhibited by any tested bacteria. However, it was effective at the higher concentrations against three microorganisms, but its diameter of inhibition zones was lower than gentamicin in all concentrations. Synergetic effects were observed by curcumin and bixin combination against S. aureus (FICI ≤ 0.5), but they act as an antagonist against E. coli and L. innocua. The results of the synergy test were confirmed by the isobologram curves.

Anti-bacterial Effects of Allium atroviolaceum Hydroalcoholic Extract on Oral Bacteria of Streptococcus viridans Groups

: In light of the escalating global concern over antibiotic resistance, this study aimed to evaluate the antimicrobial activity of the hydroalcoholic extract of Allium atroviolaceum and compare it with 0.2% chlorhexidine using the well diffusion, minimum inhibitory concentration (MIC), and minimum bactericidal concentration (MBC) methods against Streptococcus mitis (ATCC 6249), Streptococcus mutans (PTCC 16836), Streptococcus sanguinis (PTCC 1449), and Streptococcus salivarius (PTCC 1448). The well diffusion method revealed the inhibitory effect of the extract, with the highest activity observed against Streptococcus salivarius. Subsequently, MIC and MBC values were determined, indicating that the hydroalcoholic extract had MIC and MBC values of 3.12 mg/mL against Streptococcus sanguinis and 6.25 mg/mL against other strains (Streptococcus mitis, Streptococcus mutans, Streptococcus sanguinis, and Streptococcus salivarius). Chlorhexidine exhibited significantly lower MIC and MBC values of 0.0003%. Based on literature reviews, Allium species exhibit antimicrobial properties. The findings highlight the potential of Allium atroviolaceum extract as an alternative or complementary antimicrobial agent and warrant further investigation to identify its bioactive components and explore their mechanisms of action. This study contributes to understanding natural antimicrobial agents and their potential applications against bacterial infections.

In vitro anti-Helicobacter pylori activity and the underlining mechanism of an empirical herbal formula - Hezi Qingyou.

Helicobacter pylori (H. pylori) is thought to primarily colonize the human stomach and lead to various gastrointestinal disorders, such as gastritis and gastric cancer. Currently, main eradication treatment is triple or quadruple therapy centered on antibiotics. Due to antibiotic resistance, the eradication rate of H. pylori is decreasing gradually. Therefore, searching for anti-H. pylori drugs from herbal sources has become a strategy for the treatment. Our team proposed a Hezi Qingyou Formula (HZQYF), composed of Chebulae Fructus, Ficus hirta Vahl and Cloves, and studied its anti-H. pylori activity and mechanism. Chemical components of HZQYF were studied using UHPLC-MS/MS and HPLC. Broth microdilution method and agar dilution method were used to evaluate HZQYF's antibacterial activity. The effects of HZQYF on expression of adhesion genes (alpA, alpB, babA), urease genes (ureE, ureF), and flagellar genes (flaA, flaB) were explored using Reverse Transcription-quantitative Polymerase Chain Reaction (RT-qPCR) technology. Effects on morphology and permeability of the extracellular membrane were studied using scanning electron microscopy (SEM) and N-phenylnaphthalen-1-amine (NPN) uptake. Effect on urease activity was studied using a urease kinetics analysis in vitro. Immunofluorescence staining method was used to examine the effect on adhesion. Western blot was used to examine the effect on cagA protein. Minimum inhibitory concentration (MIC) values of the formula against H. pylori clinical strains and standard strains were 80-160 μg/mL, and minimum bactericidal concentration (MBC) values were 160-320 μg/mL. The formula could down-regulate the expression of adhesion genes (alpA, alpB, babA), urease genes (ureE, ureF) and flagellar genes (flaA, flaB), change the morphology of H. pylori, increase its extracellular membrane permeability, and decrease its urease activity. Present studies confirmed that HZQYF had promising in vitro anti-H. pylori activities and demonstrated its possible mechanism of action by down-regulating the bacterial adhesion, urease, and flagellar gene expression, which provided scientific bases for further clinical investigations.

Phytochemical Characterization, Antimicrobial Activity, Pharmacokinetic, in silico Molecular Docking and Interaction Analysis of Ajwa (Phoenix dactylifera L.) Palm Date Seeds

Background: There is growing evidence that antibiotic resistance is increasing. As a result, the efficacy of these antibiotics is gradually declining. This poses a serious health risk in terms of treatment strategies. Therefore, the scientific community is continuously putting all efforts into looking for novel and green therapeutics to overcome the problem of antibiotic resistance. Objectives: The aim of this study is to investigate the chemical composition of the methanolic extracts obtained from Phoenix dactylifera seeds, known agricultural waste, to identify new bioactive compounds and to examine the antibacterial and antifungal potentials. Materials and Methods: Phytochemical profiling was performed by the gas chromatography-mass spectrometry (GC-MS) technique. For the antibacterial activity of the methanolic extract, 12 microorganisms were selected, including eight bacteria ( Escherichia coli ATCC 35218, Pseudomonas aeruginosa ATCC 27853, Enterobacter cloacae, Enterococcus faecium, Staphylococcus hominis, Staphylococcus aureus, Staphylococcus epidermidis, and Klebsiella pneumoniae ATCC 27736) and four Candida species (C. albicans ATCC 10231, C. tropicalis ATCC 1362, C. utilis ATCC 9255, and C. guilliermondii ATCC 6260). The antimicrobial activity of the plant extract was supported by in silico molecular docking analysis. Results: The obtained results from the GC-MS technique revealed the presence of 51 compounds, of which 6-octadecenoic acid (Z) was identified as the major component. The tested extract exhibited the highest zone of inhibition against S. aureus (growth inhibition zone 14.66 ± 0.57 mm). In addition, minimal inhibitory concentration (MIC) and minimal bactericidal concentration values obtained against S. aureus were 1.4 and 5.6 mg/mL, respectively. Regarding the antifungal assay, C. albicans was the most sensitive one to the extract among all the tested Candida strains (14.33 mm) (MIC: 1.4 mg/mL, minimal fungicidal concentration (MFC): 11.2 mg/mL). The binding free energies and root mean square deviation values obtained from the interaction of phytochemicals with two different target receptors (1JIJ and 2QZW for TyrRS from S. aureus and aspartic proteinase from C. albicans) were also determined. Ergost-5-en-3-ol, (3beta) established hydrogen, electrostatic, alkyl, and pi-alkyl interactions with five different amino acid residues (Asp40, Asp80, Pro53, His50, and Phe54) located at the TyrRS receptor of S. aureus. On the other hand, hexadecanoic acid and methyl ester established hydrogen, electrostatic, pi-sigma, and alkyl interactions with five different amino acid residues (Thr222, Asp86, Asp218, Tyr84, and Ile123) located at the aspartic proteinase receptor of C. albicans. These interactions contributed to the stability of the complex and, hence, to the biological activity of the P. dactylifera compounds. Conclusion: Our results highlighted that methanolic extract from date seeds can be a natural source of chemical compounds with promising antibacterial and antifungal activities, as demonstrated using both in vitro and in silico approaches.

Antioxidant and antimicrobial activities of mango peel and radish peel-a comparative investigation

The present study investigated the antioxidant and antimicrobial activities of Bao mango and daikon radish peel (Thai variety) ethanolic extracts. The percentage extraction yield of radish peel was higher compared to the mango peel (p < 0.05). However, Mango peel extract (MPE) contained higher total phenolic content (TPC) than radish peel extract (RPE) (p < 0.05). Similar to the TPC value, antioxidant activities including DPPH radical scavenging activity, reducing power, and peroxidation inhibition were higher in the MPE, compared to the RPE, except for metal chelating activity. The antimicrobial analyses suggested that the MPE showed lower minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) values compared to the RPE (p < 0.05) against Gram-positive and Gram-negative bacteria. High-performance liquid chromatography (HPLC) revealed that mangiferin was the major phenolic compound present in MPE, followed by 3, 4 dihydroxybenzoic acid. Therefore, MP could be used as a promising natural antioxidant and antimicrobial agent for food applications.