Antibacterial Activity Of Compounds Research Articles

ANTIBACTERIAL POTENTIAL OF LIME (Citrus aurantifolia) ON THE GROWTH OF Streptococcus mutans

Streptococci have a variety of solid virulence factors that allow various infections to occur. Streptococcus mutans is an obligate biofilm organism and is considered the primary etiology of dental caries. Lime (Citrus aurantifolia) is widely consumed because of its natural safety factors and is a vital ingredient in most herbal ingredients with antibacterial properties. Prevention in dentistry needs to be improved, one of which is through the potential of herbal plants to reduce world health problems, especially in Indonesia. Objective To determine the possibility of lime antibacterial compounds inhibiting the growth of Streptococcus mutans. Streptococcal groups, especially S. mutans, are aciduric and acidogenic organisms and can create environmental conditions that lethal to other bacteria. Streptococcus mutans produces several extracellular sucrose metabolite enzymes that contribute to the organism's ability to cause dental caries. Streptococcal virulence factors are usually due to adesin attachment to cell surface proteins, glucosyltransferase (GTF) production, acid production, and acid tolerance. Oranges are one of the largest plant species distributed throughout the world. Plants of the citrus genus are mainly valued for their edible fruit and traditional medicinal value and have an important role in health. Lime is a herbal plant that has the potential as an antibacterial against streptococci because it contains beneficial active compounds such as saponins, flavonoids, citric acid, amino acids, essential oils, resins, glycosides, vitamin B1, vitamin C, citric acid, fats, iron, calcium, sulfur, phosphorus, and is expected to be a choice of chemical drugs that have many side effects. Conclusion Lime is a herbal plant that contains antibacterial compounds that show various biological activities, are proteolytic and lipolytic, and contain active antibacterial compounds that are expected to reduce the incidence of dental and oral diseases.

The Antimicrobial Efficacy Against Selective Oral Microbes, Antioxidant Activity and Preliminary Phytochemical Screening of Zingiber officinale.

IntroductionGinger (Zingiber officinale) has been one of the most commonly consumed herbal medicines for a long time to treat several common diseases. Antibacterial activity, antioxidant properties and many bioactive compounds in ginger have been identified previously, which could be used as an alternative method to treat many infectious diseases.MethodsThe current study evaluates ginger’s biochemical profile using qualitative and quantitative analysis and its bioactive potentials using antioxidant and antimicrobial assays against Streptococcus mutans and selective oral microbes. HPLC analysis was performed for the quantitative analysis. DPPH and disc diffusion assays were used for antioxidant and antimicrobial activities. The antimicrobial activity was checked against Streptococcus mutans, Enterococcus faecalis, Staphylococcus spp., and Lactobacillus spp. All solvents were removed by rotary evaporation before testing the dried extracts.ResultsThe observed IC50 value showed that distilled water extract exhibited the highest antioxidant activity (43.9), followed by ethanol extract (52.4), and the lowest activity was observed in n-butanol extract (91.2) and n-hexane (90.6). Different plant extracts have shown significant antibacterial activity (p = 0.001) against each bacterium. The highest antibacterial activity against tested bacteria was observed in n-hexane, chloroform and ethanol extracts. In comparison, the ethyl acetate, n-butanol and water extracts showed low antibacterial activity.ConclusionThis study emphasizes that Zingiber officinale (Z. officinale) against Gram-positive bacteria is an effective antimicrobial herb. Furthermore, it can be used as a potential natural source of antioxidants. Further studies on the toxicity analysis of ginger are recommended.

Efek ekstrak bunga telang (Clitoria ternatea) sebagai anti bakteri alami terhadap pertumbuhan bakteri Staphylococcus aureus

This research was conducted to determine the effect of the extract of telang flower (Clitoria ternatea) as a natural antibacterial on the growth of Stapylococcus aureus bacteria in terms of the results of the inhibition test and phytochemical screening. This study used 5 treatments with 5 replications in positive control and negative control, for the extract treatment using duplo replication. P0 as a positive control using Amoxicillin antibiotic, P0 as a negative control using a blank disk, P1 as a treatment using a telang flower extract with a concentration of 80%, P2 as a treatment using a telang flower extract with a concentration of 90%, and P3 a treatment using a telang flower extract with a concentration of 100 %. The results of the inhibition zone measurements showed the highest average in the positive control. The average diameter of the inhibition zone using the Agar Well Diffusion Method showed a significant difference (P<0.05). These results are supported by the ANOVA test with H1 accepted so that it can be said that there is an effect of telang flower extract (Clitoria ternatea) on the growth of Staphylococcus aureus bacteria. The results of phytochemical screening showed that the telang flower extract contained antibacterial active compounds, namely flavonoids, tannins, saponins, alkaloids, steroids and terpenoids.

Design, synthesis and anti-Mycobacterium tuberculosis evaluation of new thiazolidin-4-one and thiazolo[3,2-a][1,3,5]triazine derivatives

In response to the urgent need to encounter infection diseases, and upon increasing concerns about the devastating effects of tuberculosis (TB), the promising thiazolidin-4-one scaffold was used as a starting point to design and synthesize seventeen new compounds, relying on the pharmacophoric features of different anti-Mycobacterium tuberculosis and antibacterial active compounds. Thiazolidin-4-one was elaborated to result in bi-functioning formation, and further ring fusion into a thiazolo[3,2-a][1,3,5]triazine, which was hybridized with different heterocyclic rings and sulfonamide moieties. All the newly synthesized compounds were evaluated for their activity against drug sensitive (DS), multi-drug resistant (MDR) and extensive drug resistant (XDR) Mycobacterium tuberculosis (Mtb) strains. Additionally, their anti-bacterial activity against several bronchitis causing-bacteria (ATCC) and their antifungal activity were assessed. Several compounds showed promising results regarding all of the mentioned assays without any antifungal activities. Particularly, compound 3 showed a promising activity against the three Mtb strains (DS, MDR and XDR) with MIC of 2.49, 9.91 and 39.72 µM, respectively. Furthermore, compound 7c revealed antituberculosis activity with MIC of 2.28, 18.14 and 36.31 µM against DS, MDR and XDR strains, respectively. Both of compounds 3 and 7c surpassed azithromycin on several bronchitis causing-bacteria and showed enhanced inhibitory activity against Mycobacterium tuberculosis enoyl-acyl carrier protein reductase (InhA), with IC50 of 3.90 and 2.47 µM, respectively. The enzymatic activity was augmented by the binding characteristics of 3 and 7c in the InhA active site. Further investigations confirmed their safety on normal cell lines, and promising predicted ADME characteristics.

Synthesis, antibacterial, antibiofilm evaluation and molecular docking studies of 3-methyl- 2-propyl-2H-[1,2,4]triazolo[4,3b] [1,2,4,6]thiatriazine-1,1-dioxide

ABSTRACT. In the current study, a simple method for the synthesis of 3-methyl-2-propyl-2H-[1,2,4]triazolo[4,3b][1,2,4,6]thiatriazine-1,1-dioxide (2) was carried out. In the presence of pyridine, a reaction between amidine (1) and sulfuryl chloride occurs. FTIR spectroscopy, 1H and 13C NMR, mass spectra, and elemental analysis were utilized in order to verify the structure of a novel synthetic molecule. The antibacterial activities of compound (2) were tested against eight pathogenic bacteria and the minimum inhibitory concentration as well as minimum bactericidal concentration were determined. Moreover, the possible antibiofilm effect of compound (2) was evaluated. Molecular docking was investigated to determine the interaction between compound (2) and eight crystal structures of bacterial and yeast proteins associated with virulence activity and antimicrobial resistance. Our results showed that the new 3-methyl-2-propyl-2H-[1,2,4]triazolo[4,3b][1,2,4,6]thiatriazine-1,1-dioxide (2) compound has a moderate antibacterial activity toward the selected pathogenic bacteria. The obtained MICs varied from 32 to 512 µg/mL being the lowest values attributed to Staphylococcus epidermidis ATCC 14990 and Streptococcus mutans ATCC 25175 (MIC = 32 µg/mL).We noted also that heterocyclic compound (2) may inhibit bacterial biofilm formation at concentration depend manner with a lowest value obtained against S.mutans ATCC 25175 (BIC50 = 490 µg/mL). Molecular docking showed a promising inhibitory activity of compound (2) on TetM-mediated tetracycline resistance (3J25) and Staphylococcus aureus gyrase (3G7B) with lower binding energy compared to the other target proteins.
 
 KEY WORDS: Synthesis, Thiatriazine-1,1-dioxide, Antibacterial, Antibiofilm, Molecular docking
 Bull. Chem. Soc. Ethiop. 2022, 36(1), 109-117. 
 DOI: https://dx.doi.org/10.4314/bcse.v36i1.10

Phytochemical Screening of Active Secondary Metabolites and Antibacterial Activity Kaffir Lime Leaf (Citrus hystrix) and Tumeric Leaf (Curcuma longa Linn.) Against Escherichia coli

This study aims to determine the content of active compounds of secondary metabolites and antibacterial activity of secondary metabolites from a maceration of turmeric leaf (Curcuma longa Linn.) and kaffir lime leaf (Citrus hystrix) against Escherichia coli (E. coli). Each sample of kaffir lime leaf and turmeric leaf was extracted by maceration method using 96% ethanol solvent for 3 x 24 hours and the solvent was changed every 1 x 24 hours, then the filtered filtrate was thickened using a rotary evaporator. The phytochemical screening test was carried out by qualitative method using chemical reagents. The antibacterial activity test of the extract of the combination of turmeric leaves (Curcuma longa Linn.) and kaffir lime leaves (Citrus hystrix) used the Punch Hole Diffusion method with various concentrations of 20%, 40%, 60%, 80%, and 100%. The results showed that the combined extract of turmeric leaf (Curcuma longa Linn.) and kaffir lime leaf (Citrus hystrix) contained secondary metabolites in the form of flavonoids, alkaloids, steroids, tannins, and saponins. The optimum zone of inhibition to inhibit the growth of E. coli produced was 9.73 ± 0.78 mm. Overall, it can be concluded that the combined extract of turmeric leaf (Curcuma longa Linn.) and kaffir lime leaf (Citrus hystrix) has potential as an alternative to antibacterial active compounds.

Synthesis of N-Methylspiropyrrolidine Hybrids for Their Structural Characterization, Biological and Molecular Docking Studies

A set of novel N-methylspiropyrrolidine hybrids have been synthesized regio selectively employing 1,3-dipolar cycloaddition reaction of substituted chalcones with azomethine ylides (work up in situ from isatin and sarcosine). The spiropyrrolidines structures were studied using FT-IR, 1H and 13C NMR spectroscopic data, and was finally confirmed by X-ray diffraction study. Hirshfeld surface analysis was correlated with X-ray diffraction and described different intermolecular contacts. Good antibacterial activity was reported against gram-positive and gram-negative bacterial strains of Bacillus subtillis, Enterococcus faecalis, E. coli, and Pseudomonas aeruginosa. Initially, antibacterial activity of compounds was confirmed by the zone of inhibition. Most of the compounds have shown MIC and MBC in the range between 50-200 µg∕mL against both types of bacteria. Further, for mechanism of action, the tested compounds were checked for the inhibition of an established bacterial drug target, DNA gyrase using in silico approaches.

Antibacterial Electrospun Polycaprolactone Nanofibers Reinforced by Halloysite Nanotubes for Tissue Engineering.

Due to its slow degradation rate, polycaprolactone (PCL) is frequently used in biomedical applications. This study deals with the development of antibacterial nanofibers based on PCL and halloysite nanotubes (HNTs). Thanks to a combination with HNTs, the prepared nanofibers can be used as low-cost nanocontainers for the encapsulation of a wide variety of substances, including drugs, enzymes, and DNA. In our work, HNTs were used as a nanocarrier for erythromycin (ERY) as a model antibacterial active compound with a wide range of antibacterial activity. Nanofibers based on PCL and HNT/ERY were prepared by electrospinning. The antibacterial activity was evaluated as a sterile zone of inhibition around the PCL nanofibers containing 7.0 wt.% HNT/ERY. The morphology was observed with SEM and TEM. The efficiency of HNT/ERY loading was evaluated with thermogravimetric analysis. It was found that the nanofibers exhibited outstanding antibacterial properties and inhibited both Gram- (Escherichia coli) and Gram+ (Staphylococcus aureus) bacteria. Moreover, a significant enhancement of mechanical properties was achieved. The potential uses of antibacterial, environmentally friendly, nontoxic, biodegradable PCL/HNT/ERY nanofiber materials are mainly in tissue engineering, wound healing, the prevention of bacterial infections, and other biomedical applications.

Screening of antibacterial compounds with novel structure from the FDA approved drugs using machine learning methods.

Bacterial infection is one of the most important factors affecting the human life span. Elderly people are more harmed by bacterial infections due to their deficits in immunity. Because of the lack of new antibiotics in recent years, bacterial resistance has increasingly become a serious problem globally. In this study, an antibacterial compound predictor was constructed using the support vector machines and random forest methods and the data of the active and inactive antibacterial compounds from the ChEMBL database. The results showed that both models have excellent prediction performance (mean accuracy >0.9 and mean AUC >0.9 for the two models). We used the predictor to screen potential antibacterial compounds from FDA-approved drugs in the DrugBank database. The screening results showed that 1087 small-molecule drugs have potential antibacterial activity and 154 of them are FDA-approved antibacterial drugs, which accounts for 76.2% of the approved antibacterial drugs collected in this study. Through molecular fingerprint similarity analysis and common substructure analysis, we screened 8 predicted antibacterial small-molecule compounds with novel structures compared with known antibacterial drugs, and 5 of them are widely used in the treatment of various tumors. This study provides a new insight for predicting antibacterial compounds by using approved drugs, the predicted compounds might be used to treat bacterial infections and extend lifespan.

Pengaruh Ekstrak Patikan Kebo (Euphorbhia hirta Linn) Terhadap Serangan Hama Daun Sawi

Plant Pest Organisms that often attack mustard are Tritip caterpillar (Plutella xylostella L), armyworm (Spodoptera litura F), growing point caterpillar (Crocidolomia binotalis Zel), common pests that often attack mustard, namely Leaf Grasshopper (Phyllium pulchrifolium), Nezara viridula L, and Chrysodeixis chalcites. One of the environmentally friendly pest control techniques is the use of pesticides derived from plants which are commonly called biopesticides. Patikan kebo (Euphorbia hirta L) was known to contain antibacterial active compounds that can be used as organic herbicides. This study used patikan kebo extract with several concentrations to suppress the attack of mustard leaves destroying pests. The research took place in a vegetable growing area and was carried out for 40 days from sowing to harvesting. The research was conducted using an experimental method. The results of this study showed that all treatments of patikan kebo extract were able to suppress the attack of mustard leaf pests and the use of a very significant concentration was found in (7.5 ml) with the lowest attack intensity of 4.79%.

Discovery of Novel Pleuromutilin Derivatives as Potent Antibacterial Agents for the Treatment of MRSA Infection.

A series of novel pleuromutilin derivatives containing nitrogen groups on the side chain of C14 were synthesized under mild conditions. Most of the synthesized derivatives displayed potent antibacterial activities. Compound 9 was found to be the most active antibacterial derivative against MRSA (MIC = 0.06 μg/mL). Furthermore, the result of time-kill curves showed that compound 9 had a certain inhibitory effect against MRSA in vitro. Moreover, according to a surface plasmon resonance (SPR) study, compound 9 (KD = 1.77 × 10−8 M) showed stronger affinity to the 50S ribosome than tiamulin (KD = 2.50 × 10−8 M). The antibacterial activity of compound 9 was further evaluated in an MRSA-infected murine thigh model. Compared to the negative control group, tiamulin reduced MRSA load (~0.7 log10 CFU/mL), and compound 9 performed a treatment effect (~1.3 log10 CFU/mL). In addition, compound 9 was evaluated in CYP450 inhibition assay and showed only moderate in vitro CYP3A4 inhibition (IC50 = 2.92 μg/mL).

Antibacterial activity and volatile organic compounds sensing property of polypyrrole-coated cellulosic paper for food packaging purpose

Antibacterial activity and volatile organic compounds sensing property of polypyrrole-coated cellulosic paper for food packaging purpose

Potential of Antibacterial Activity in Natural Ingredients (Betel Leaves, Basil Leaves, Avocado Seeds, Lemongrass, Garlic) As Natural Hand Sanitizers: Journal Review

In an effort to reduce the use of alcohol-based hand sanitizers because of their quite dangerous impact on the skin, natural hand sanitizers are an alternative. The antibacterial substances in betel leaves, basil leaves, avocado seeds, lemongrass, and garlic can be used as materials for natural hand sanitizers. The purpose of this study was to collect, identify, and compare journals about the effectiveness of antibacterial agents in natural ingredients that are used as natural hand sanitizers. Using the journal review method through reviewing the contents of journals that discuss antibacterial activity, the results show that the five phytochemical compounds contain active antibacterial compounds so that they have the potential to make natural hand sanitizers, as well as the antibacterial inhibition zone of these five ingredients showing high results with strong to very strong categories. It was concluded that the five ingredients could be used as natural hand sanitizer materials. However, betel leaves are preferred because of their largest inhibition zone, 3.1-4.0 cm.

Uji Aktivitas Anti Bakteri Dari Formula Ekstrak Daun Ciplukan (Physalis angulata L.) dan Batang Kayu Manis (Cinnamomum burmannii) Secara In Vitro Test

Ciplukan leaves (Physalis angulata L.) and Cinnamon (Cinnamomum burmannii) are one of medicinal plants that contain antibacterial active compounds. This study aims to determine the antibacterial activity of the combination formula between extracts of ciplukan leaves and cinnamon sticks against the growth of Staphylococcus aureus bacteria in Vitro. Ciplukan leaves (Physalis angulata L.) and cinnamon (Cinnamomum burmannii) were extracted by the maceration method with 70% ethanol. Ciplukan leaf extract (Physalis angulata L.) and cinnamon (Cinnamomum burmannii) were tested against Staphylococcus aureus bacteria using the good method by measuring transmittance on a spectrophotometer at a wavelength of 580 nm with 3 repetitions, 100 ppml standard Septromycin solution as control positive and aquadest as a negative dick. Inhibition zone diameter of ciplukan leaf extract (Physalis angulata L.) x̄ = 12.46 mm, Cinnamon Extract (Cinnamomum burmannii) x̄ = 18.93 mm, while in the formulation group x̄ = 22.45 mm. One-way analysis of variance (ANOVA) of these data compared with Streptomycin activity (positive control) showed significant inhibitory activity by the formulated extract against S. aureus. Keywords: Antibacterial, Staphylococcus aureus, Ciplukan leaves (Physalis angulata L.) and Cinnamon (Cinnamomum burmannii)

Synthesis and Antimicrobial Evaluation of Amino Acid Naphthoquinone Derivatives as Potential Antibacterial Agents

Background: The synthesis and biological evaluation of 1,4-naphthoquinone derivatives are of great interest since these compounds exhibit strong antibacterial, antifungal, antimalarial, and anticancer activities. The electronic properties of naphthoquinones are usually modulated by attaching functional groups containing nitrogen, oxygen, and sulfur atoms, which tune their biological potency and selectivity. Methods: A series of 13 amino acid 1,4-naphthoquinone derivatives was synthesized under assisted microwave and ultrasound conditions. The antibacterial activity of compounds was tested against American Type Culture Collection (ATCC): Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, and Enterococcus faecalis, as well as 2 multidrug resistant pathogens: E. coli and S. aureus from clinical isolated. Minimal inhibitory concentration (MIC) was determined using the broth microdilution method. Results: MIC of derivatives 4–11, 14, and 16 showed antimicrobial activity against Gram-positive and Gram-negative bacteria. Antimicrobial activities of the compounds 4–8 and 14 were ≤MIC 24.7 μg mL⁻¹ against all the reference strains; even more, compound 6 showed the most potent activity with an MIC of 3.9 μg mL⁻¹ on S. aureus. On the clinical isolated, the compounds 7, 8, and 14 showed an MIC of 49.7 and 24.7 μg mL⁻¹ against S. aureus and E. coli, respectively. About ADME properties and Osiris analysis, the compounds 4–16 presented high gastrointestinal absorption and good characteristics for oral bioavailability, and compound 14 was the less toxic. Conclusion: Amino acid 1,4-naphthoquinone derivatives showed good in vitro antibacterial activity against clinical strains, and modifications on C-3 with a chloride atom enhanced the efficiency against the same pathogens.

New Unnatural Gallotannins: A Way toward Green Antioxidants, Antimicrobials and Antibiofilm Agents.

Nature has been a source of inspiration for the development of new pharmaceutically active agents. A series of new unnatural gallotannins (GTs), derived from d-lyxose, d-ribose, l-rhamnose, d-mannose, and d-fructose have been designed and synthesized in order to study the protective and antimicrobial effects of synthetic polyphenols that are structurally related to plant-derived products. The structures of the new compounds were confirmed by various spectroscopic methods. Apart from spectral analysis, the antioxidant activity was evaluated by 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical-scavenging and iron reducing power (FRAP) assays. Antibacterial activity of compounds was tested in vitro against Staphylococcus aureus ATCC 29213, Enterococcus faecalis ATCC 29212 (reference and control strains), three methicillin-resistant isolates of S. aureus, and three isolates of vancomycin-resistant E. faecalis. For screening of antimycobacterial effect, a virulent isolate of Mycobacterium tuberculosis and two non-tuberculous mycobacteria were used. Furthermore, antibiofilm activity of structurally different GTs against S. aureus, and their ability to inhibit sortase A, were inspected. Experimental data revealed that the studied GTs are excellent antioxidants and radical-scavenging agents. The compounds exhibited only a moderate antibacterial effect against Gram-positive pathogens S. aureus and E. faecalis and were practically inactive against mycobacteria. However, they were efficient inhibitors and disruptors of S. aureus biofilms in sub-MIC concentrations, and interacted with the quorum-sensing system in Chromobacterium violaceum. Overall, these findings suggest that synthetic GTs could be considered as promising candidates for pharmacological, biomedical, consumer products, and for food industry applications.

Antibacterial Activity of Ethanolic Extract, n-Hexane Fraction, and Chloroform Fraction of Binahong Leaves (Anredera Cordifolia) on Escherichia Coli and its Phytochemical Screening

Binahong leaves (Anredera cordifolia (Ten.) Steenis) are known to contain antibacterial activity compounds. The compounds contained in binahong leaves include flavonoids, alkaloids, saponins, and tannins. Escherichia coli is a gram-negative bacteria that often causes infections such as diarrhea. The purpose of this study was to determine the effect of ethanolic extract, n-hexane fraction, and chloroform fraction of binahong leaves on the growth of Escherichia coli bacteria and its phytochemical screening This research used ethanolic extract, hexane fraction and chloroform fraction of binahong leaves against Escherichia coli bacteria with concentrations of 12.5, 25 and 50% The positive control was chloramphenicol and the negative control was DMSO The method used disk diffusion technique, marked the presence of clear areas around the paper disc that showed an obstacle to bacterial growth phytochemical screening of alkaloids, flavonoids, saponins and tannins using a test tube. The result showed antibacterial activity against the growth of Escherichia coli with the diameter of the inhibition zone at concentrations of 12.5, 25, and 50%, namely the hexane fraction of 8.16; 9.73 and 12.93 mm. At the chloroform fraction 7.67; 8.47 and 9.87 mm. and the ethanolic extract of 7.33; 9.95 and 13.32 mm. The result of the largest inhibition zone was the ethanolic extract of binahong leaves with a concentration of 50%. The results of phytochemical screening using a test tube showed that the compounds contained in the ethanolic extract were flavonoids, alkaloids, saponins, and tannins.

Synthesis of chitosan-salicylaldehyde/vanillin Schiff base as antibacterial active compound on cotton fabrics

In this study, chitosan-salicylaldehyde/vanillin was synthesis by reflux method via condensation reaction. The aim of this study was to apply the Schiff base compound to cotton fabrics and test its antibacterial activity. The chitosan-salicylaldehyde/vanillin Schiff base was applied to cotton fabrics using spray method and antibacterial activity tested using turbidimetric method. The Schiff base was achieved with formation of brownish-yellow solids. The characterization of chitosan-salicylaldehyde Schiff base showed C=N vibration at 1649.18 cm−1, the ratio of Schiff base formed was 0.403 in a yield of 56% (b/b). The treated cotton fabrics using chitosan-salicylaldehyde/vanillin Schiff base showed optimum inhibition against Staphylococcus aureus up to 69% at 6 hours and Escherichia coli up to 7% at 18 hours.

Isolation of a Morphinan Alkaloid and a Methoxybenzoic Acid with The Investigation on The Antibacterial Effect of Alphonsea cylindrica King Leaves

Alphonsea cylindrica King belongs to the family Annonaceae, which is traditionally used to treat rheumatism, bruises, and edema. Investigation of its antibacterial properties was carried out on hexane and dichloromethane crude extracts using agar diffusion method and minimum inhibitory concentration against ESKAPE pathogens. Both extracts showed positive results in inhibiting E. faecium, S. aureus, and K. pneumoniae, while the dichloromethane extract showed further inhibition against P. aeruginosa. A morphinan alkaloid, O-methylpallidinine (1), along with a methoxybenzoic acid, isovanillic acid (2), were isolated from the dichloromethane leaf extract of the plant and elucidated via NMR spectroscopy, FTIR spectroscopy, UV-vis spectroscopy, and GC-MS, and compared with the reported data. Both compounds are reported for the first time from A. cylindrica, while O-methylpallidinine was isolated as natural product for the first time from the family Annonaceae. Both 1 and 2 showed low activity against S. aureus with an IC50 value of 371.82 μg/mL and 385.37 μg/mL, respectively. This is the first report on the antibacterial activity of compound 1. The results can be used as future references for the discovery of morphinans and the potential of A. cylindrica as an antibacterial source.

Synthesis, characterization, biological evaluation, BSA binding properties, density functional theory and molecular docking study of Schiff bases

In order to make an advancement in the discovery of the more effective ways to eliminate ROS, which causes oxidative stress or to eliminate the harmful microorganisms from the organism in humans, and bearing in mind the fact that Schiff bases belong to a class of biologically active compounds, a series of Schiff bases were synthesized and tested to evaluate their antioxidant and antimicrobial activity. DPPH, superoxide anion, and reducing power assays were used in assessing the antioxidative potential of studied compounds. Among tested compounds, the B1 compound showed the largest activity in all antioxidant assays. IC50 values in DPPH radical and superoxide anion radical scavenging activities were 15.64 µg/mL and 54.72 μg/mL, respectively (even better than positive control ascorbic acid). Moreover, these compounds had effective reducing power (absorbance was in the range 2.415–1.270, depending on the concentrations tested). A high antioxidant effect was also found in B2 and C3 compounds. The remaining tested compounds showed slightly weaker antioxidant activity. Besides, the antioxidative capacity of selected compounds was studied by density functional theory (DFT). The antimicrobial activity of B1, B2 and C1–4 compounds was examined towards eight microorganisms (four species of bacteria and five species of fungi) using the microdilution method. Among tested compounds, B1 and B2 showed marked antibacterial activity (MIC values ranged from 0.15 to 1.25 mg/mL), while C4 and B1 compounds showed very strong antifungal activity (MIC values ranged from 0.07 to 1.25 mg/mL). Molecular docking simulations were performed to better understand the binding modes selected compounds with DNA and BSA, as well as to comprehend their antioxidative or antimicrobial activity.