Synthesis and antibacterial activity evaluation of octapeptin derivatives / 药学学报

Octapeptin has strong antibacterial activity against Gram-negative bacteria such as Escherichia coli, Klebsiella pneumoniae and Acinetobacter baumannii, while it also has activity against some Gram-positive bacteria. This study used natural octapeptin A3 and B3 as lead compounds for structural modification. Twenty-one peptide derivatives (including A3 and B3) containing eight amino acid residues were prepared by solid-phase synthesis, and evaluated for antibacterial activity and renal cytotoxicity. Among them, three compounds 6, 7 and 17 exhibited broad-spectrum antibacterial activity and significantly enhanced the activity for Gram-positive bacteria while maintaining the activity of Gram-negative bacteria. Several compounds improved the activity for Pseudomonas aeruginosa. Compound 7 was active against all test strains and had relatively low renal cytotoxicity. The results provide a basis for the further development of novel polypeptide antibiotics.

Synthesis and antibacterial activities of phosphonate derivatives containing aminothiazoloxime fragment / 药学学报

Based on the principle of molecular hybridization, fifteen compounds were designed and synthesized through the combination of aminothiazoloxime and phosphonate fragment. The results showed that these compounds had better inhibitory effects on the tested bacteria. In particular, the activities of compounds Ⅲf and Ⅲi against S. aureus, E. coli, methicillin-resistant S. aureus (MRSA) and fluoroquinolone-resistant E. coli (FREC) were the most significant, the minimal inhibitory concentration (MIC) of Ⅲf was 1, 8, 4, 16 μg·mL-1 respectively, and the MIC of Ⅲi was 4, 4, 16, 8 μg·mL-1 respectively, which were slightly lower than that of the control drug oxacillin, and their anti-E. coli, MRSA and FREC activities were superior to that of the control drug oxacillin. Their activities to S. aureus were close to that of oxacillin, and to E. coli, MRSA and FREC were superior to that of oxacillin, which is worthy of further study.

Antibacterial activity of Ricinus communis plant extract against antibiotic resistant Helicobacter pylori and Gluconobacter oxydans isolated from fresh apple juices samples

Abstract Bacteria were isolated from samples of Fresh Apple juices from shops of three different localities of Lahore. Analysis of samples from Liberty, Anarkali and Yateem khana Markets show different levels of contamination. There were pathogenic and non-pathogenic bacteria in all samples and were identified by the morphological and biochemical tests. Most of the plasmids of pathogenic bacteria were 4kb in their molecular size. Ribotyping of 16S ribosomal RNA gene sequencing was done to confirm Helicobacter pylori strain and Gluconobacter oxydans. The highest sensitivity of 210mm was shown by Enterobacter sp. against Aztheromysine disk (15µg) while Micrococcus sp. was highly resistant against all of the Antibiotics applied. The antibiotic resistance of pathogenic bacteria was also checked against Ricinus communis plant's extracts, all isolated bacterial pathogens were resistant but only, E.coli was inhibited at 300µl of the extracts. Presence of pathogenic bacteria in Apple juice samples was due to contamination of sewage water in drinking water while some of these pathogenic bacteria came from Apple's tree and other from store houses of fruits.

Resumo As bactérias foram isoladas de amostras de suco de maçã fresco de lojas de três diferentes localidades de Lahore. A análise de amostras dos mercados Liberty, Anarkali e Yateem khana mostram diferentes níveis de contaminação. Havia bactérias patogênicas e não patogênicas em todas as amostras e foram identificadas pelos testes morfológicos e bioquímicos. A maioria dos plasmídeos de bactérias patogênicas tinha 4 kb em seu tamanho molecular. A ribotipagem do sequenciamento do gene do RNA ribossômico 16S foi realizada para confirmar a cepa de Helicobacter pylori e Gluconobacter oxydans. A maior sensibilidade de 210 mm foi mostrada por Enterobacter sp. contra disco de azteromisina (15µg) enquanto Micrococcus sp. foi altamente resistente a todos os antibióticos aplicados. A resistência a antibióticos de bactérias patogênicas também foi verificada contra extratos de plantas de Ricinus communis, todos os patógenos bacterianos isolados foram resistentes, mas apenas E. coli foi inibida em 300µl dos extratos. A presença de bactérias patogênicas nas amostras de suco de maçã deveu-se à contaminação da água de esgoto na água potável, enquanto algumas dessas bactérias patogênicas vieram da árvore da maçã e outras de armazéns de frutas.

Actividad antibacteriana in vitro del extracto y aceite esencial de hojas de Muña

Objetivo: comparar la actividad antibacteriana in vitro del extracto y del aceite esencial de hojas de muña (Minthostachys mollis) frente a dos géneros y cinco cepas bacterianas patógenas. Materiales y métodos: estudio experimental, enfoque cuantitativo, método modificado de pozos en agar de Kirby-Bauer utilizado para medir la actividad antibacteriana. Resultados: el rendimiento del aceite esencial fue del 1,19%. El aceite esencial al 100% fue más efectivo para inhibir el crecimiento del S. aureus, Proteus spp, K. pneumoniae, E coli y P. aeruginosa con medias de halos de inhibición de 27 mm, 25 mm, 22 mm, 21 mm y 20 mm mayores al del extracto y la doxiciclina. A su vez, inhibió el crecimiento del E. faecalis y Enterobacter spp, con mayor efectividad en comparación al extracto, doxiciclina y ciprofloxacina. Por otro lado, se observó diferencias significativas de medias de inhibición en al menos 2 de los grupos analizados con un p <0,05 y 95% de confianza, del ANOVA de un factor de Tukey y de Kruskal-Wallis. Conclusiones: el Proteus spp, S. aureus, K. pneumoniae, E. coli y P. aeruginosa fueron inhibidas por el aceite esencial de muña al 100% con mayor efectividad que por el extracto y la doxiciclina. De igual modo, en comparación con el extracto y los antimicrobianos, el aceite fue el único que frenó eficazmente el crecimiento del Enterobacter spp. y E. faecalis.

Objective: to compare the in vitro antibacterial activity of the extract and essential oil of pineapple (Minthostachys mollis) leaves against two genera and five pathogenic bacterial strains. Materials and methods: experimental study, quantitative approach, modified Kirby-Bauer agar well method used to measure antibacterial activity. Results: the essential oil yield was 1,19%. The 100% essential oil was more effective in inhibiting the growth of S. aureus, Proteus spp, K. pneumoniae, E coli and P. aeruginosa with mean inhibition halos of 27 mm, 25 mm, 22 mm, 21 mm and 20 mm greater than that of the extract and doxycycline. In turn, it inhibited the growth of E. faecalis and Enterobacter spp, with greater effectiveness compared to the extract, doxycycline and ciprofloxacin. On the other hand, significant differences in inhibition means were observed in at least 2 of the groups analyzed with a p <0,05 and 95% confidence, from Tukey's one-factor ANOVA and Kruskal-Wallis. Conclusions: Proteus spp, S. aureus, K. pneumoniae, E. coli and P. aeruginosa were inhibited by 100% essential oil of pineapple more effectively than by the extract and doxycycline. Similarly, compared to the extract and antimicrobials, the oil was the only one that effectively inhibited the growth of Enterobacter spp. and E. faecalis.

Individual Antibacterial Activity of Black Seed, Clove, and Myrrh Various Extracts Against Different Bacterial Strains

Nigella sativa (black seed), Syzygium aromaticum (clove), and Commiphora myrrha (myrrh) are examples of medicinal plants that have gained popularity in the last decades due to their high contents of phytochemical constituents and consequently to their potent biological activities. Different extracts of the aforementioned medicinal plants were prepared, using organic solvents acetone and methanol, as well as a water extract; they were evaluated separately for their antibacterial activities against human pathogenic bacteria Staphylococcus aureus, Bacillus subtilis as Gram-positive bacteria and against Gram-negative Escherichia coli, and Pseudomonas aeruginosa. The experiment was carried out using agar well diffusion techniques. Different inhibition effects were observed, which could be mainly attributed to the presence of various chemical constituents. They can be used as such as good precursors for new antibacterial agents. Data from the present study showed that E. coli was the most sensitive bacterial strain, mostly to the clove methanol extract, followed by the acetone extract on Pseudomonas, Bacillus, and Staphylococcus. Black seed and myrrh solvent extracts showed similar activity against Bacillus more than against all other isolates. All aqueous extracts, except myrrh water extract, demonstrated negligible effect on the tested bacteria, indicating moderate activity against all isolates. This variation in the efficacy could be related to the bacterial structure as well as the major phytoconstituents.

Synthesis and Biological Evaluation of Some Novel Hybrid Quinazolinone–Piperazine Derivatives as Anti-Microbial Agents

The chemical constituents quinazolinone and piperazine hold significant importance in the realm of organic compounds due to their diverse range of biological and therapeutic attributes. In an effort to investigate the possible uses of these molecules, a team of scientists synthesized a unique set of chemical substances that combined piperazine and quinazolinone structures. This research involved a comprehensive investigation into the antimicrobial properties of a set of derivatives bearing the chemical structure N-(4-oxo-2-(4-(4-(2-(Substituted phenylamino) acetyl) piperazin-1-yl) phenyl) quinazolin-3(4H)-yl) benzamide, which was successfully synthesized with high yields. The synthesized compounds were carefully characterized using a range of physical methods, including mass spectrometry, FTIR, and 1H NMR spectroscopy, in addition to physical methods such as melting point measurement and thin-layer chromatography. Subsequently, using the agar well diffusion method, these compounds were evaluated for their antibacterial activity against a panel of microbial strains, including Staphylococcus aureus, Bacillus subtilis, Escherichia coli, and Pseudomonas aeruginosa. The antifungal assay was also conducted against Candida albicans using the same approach. The broth microdilution technique was also used to establish the minimal inhibitory concentration. The synthesized compounds demonstrated impressive antifungal and antibacterial properties against every tested microbe. Notably, among the compounds evaluated, PRP7A6, PRP7A8, and PRP7A11 displayed the most potent antimicrobial effects against the pathogenic strains.

Actividad biológica de los aceites de semillas de Annona muricatay A. cherimola / Biological activity of Annona muricata and A. cherimola seed oils

Vegetable extracts have become important raw materials for food, pharmaceutical and cosmetic industries because of their biological potential. The objective of this study was to assess the biological activity of vegetable oils (VOs) extracted from Annona muricata and A. cherimola. Antibacterial activity was determined by plaque microdilution. The assessment of hemolytic inhibition and morphological alterations was performed in erythrocyte cultures by spectrophotometry and microscopy, respectively. Neutrophils were used to analyze both cytotoxicity by the trypan blue exclusion method and the effect on gelatinase granule release (MMP9) via zymography. Whereas VOs showed a mild antibacterial activity (900 µL/mL) on five ATCC bacterial strains, they had no effect on multi-resistant bacteria. In addition, VOs inhibited hydrogen peroxide induced hemolysis and did not cause erythrocyte cell abnormalities. Cytotoxicity was not detected in neutrophils and VOs were able to stimulate MMP9 release. These results support their potential use by the food and cosmetic industries due to their antioxidant, non-cytotoxic, and slight antibacterial capacities.

Los extractos vegetales adquieren importancia en la industria alimentaria, farmacéutica y cosmética, por su potencial biológico. El objetivo de este estudio fue evaluar actividad biológica de los Aceites Vegetales (AV) de semillas de Annona muricata y A. cherimola. La actividad antibacteriana se determinó mediante microdilución en placa; en cultivo de eritrocitos se evaluó inhibición hemolítica por espectrofotometría y alteraciones morfológicas por recuento microscópico; en neutrófilos se evaluó citotoxicidad por método de exclusión con azul de tripán, y el efecto sobre liberación de gránulos de gelatinasa (MMP9) mediante zimografía. Los AV presentaron actividad antibacteriana leve (900 µL/mL) en cinco cepas ATCC, pero no en bacterias multirresistentes; inhibieron la hemolisis inducida por peróxido de hidrogeno; no generaron deformaciones eritrocitarias; no se evidenció citotoxicidad en neutrófilos y estimularon la liberación de MMP9. Los resultados podrían sustentar el uso potencial de estos AV en la industria alimenticia o cosmética, gracias a su capacidad antioxidante, no citotóxica y levemente antibacteriana.

Isolation of Actinomycetes from Arachis hypogaea L. and Gossypium herbaceum L. for Screening Antibacterial and Antifungal Activities

The principal objective of the present study was to check the antimicrobial activity of Actinomycetes isolated from soil samples collected from the fields of Arachis hypogea L. and Gossipium herbaceum L. against different plant pathogenic strains. Various soil samples were isolated from fields located near the Junagadh district, Gujarat, India. Isolation was followed by a serial dilution process which was later plated on Actinomycete Isolation Agar (AIA) media. Potential colonies were subjected to screening, purification, and storage in glycerol stock. Morphological and Biochemical characterization of the isolates was performed. Isolated candidates were subjected to extraction for the production of the antimicrobial compound. The antimicrobial activity of the purified extract of isolates was tested. Total 30 actinomycete isolates were evaluated for antagonistic activity against pathogenic microorganisms. Isolates C-25, C-15, and G-1 showed the best results in the decreasing order of their potency against fungal pathogens, and C-5, C-25, C-14, and C-13 showed the best results in decreasing order of potency against bacterial pathogens. 3 isolates inhibited all 4 test fungi. 10 isolates inhibited 3 test fungi. 11 isolates inhibited 2 test fungi. 6 isolates did not inhibit any test fungi. 4 isolates show potent inhibition. 15 inhibited Macrophomina. C-10 showed a 1 cm inhibition zone & G-1 showed a 0.8 cm zone of inhibition. 12 isolates gave 0.2-0.6 cm zone and 15 isolates gave negative results against Macrophomina. C-10 showed a very potent zone of inhibition of 0.7 cm. 9 isolates showed a 0.1-0.5 cm zone of inhibition. 20 isolates did not show inhibition against Fusarium. 1 isolate C-11(a) gave the 1cm potent zone of inhibition. 15 isolates gave the 0.7-0.2cm inhibition of the growth. 14 isolates gave negative results against Alternaria fungus. From these results, it was concluded that isolates had antibacterial and antifungal activities and could be used in the development of new antibiotics for pharmaceutical or agricultural purposes.

INVESTIGATING THE ANTIBACTERIAL, ANTIOXIDANT, AND ANTI-INFLAMMATORY ACTIVITIES OF AQUEOUS AND HYDROETHANOLIC EXTRACTS OF OCIMUM BASILICUM AND OCIMUM GRATISSIMUM ON SOME GERMS RESPONSIBLE FOR AEROBIC VAGINITIS

Objective: The present work evaluates the antibacterial, antioxidant, and anti-inflammatory activities of aqueous and hydroethanolic extracts of Ocimum basilicum and Ocimum gratissimum on germs responsible for aerobic vaginitis.Methods: University Teaching Hospital of Yaoundé and Central Hospital of Yaoundé provided the germ (Staphylococcus aureus) and isolates (Enterobacter cloacae and Providencia stuartii). The extracts were obtained by maceration of the plants in water and hydroethanolic system. Phytochemical screening was assessed using the standard method; sensitivity and inhibition tests were carried out on agar medium and microplates in liquid medium. The antioxidant activity of the extracts was evaluated using the 2,2-diphenyl-1-picrilhidrazil (DPPH), 2,2’-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid (ABTS), ferric reducing antioxidant power assay (FRAP), and ?-carotene assays; total polyphenols content was obtained by the Folin Ciocalteu assay; anti-inflammatory activity by denaturation of ovalbumin.Results: Flavonoids, catechin, and tannins were abundant in the hydroethanolic extracts (56.65±3.89 and 228.94±8.42 mg EAA/g, respectively). The extracts were bactericidal for S. aureus and bacteriostatic for P. stuartii and E. cloacae. The hydroethanolic extract of the leaves of O. gratissimum has the best anti-radical activity 23.08±3.12, while that of the leaves of O. basilicum had the best-reducing power (388.36±9.96). The anti-inflammatory activity was found to be significant in the leaf extracts studied with IC50 values ??of 0.358±0.013 mg/ml for O. basilicum to 0.269±0.008 mg/ml for O. gratissimum, thus justifying their anti-inflammatory properties. The equivalent contents of primary and secondary antioxidants of the extracts were also obtained.Conclusion: The hydroethanolic extracts of Ocimum basilicum and Ocimum gratissimum have antibacterial, antioxidant, and anti-inflammatory properties.

Antibacterial activity of medicinal plants against Leptospira spp: a literature review / Actividad antibacteriana de plantas medicinales contra Leptospiraspp: una revisión de la literatura

Leptospirosis is a zoonosis caused by bacteria of the genus Leptospira that affects animals and humans. This disease is usually treated empirically due to its prevalence in precarious areas without basic sanitation. The use of medicinal plants in less industrializedsocieties has been one of the main therapeutic resources available. Considering the need to use these natural resources to combat leptospirosis in areas of socioeconomic vulnerability, this study aimed to review the literature on the use of plants with medicinal potential in the treatment of leptospirosis. The results showed that even though leptospirosis is a common disease in communities lacking basic sanitation and economic development, the number of studies on the use of plants with medicinal potential is scarce. Most of these studies come from India, and all plants investigated between 2012 and 2020 had antileptospiral action.

La leptospirosis es una zoonosis causada por bacterias del género Leptospira que afecta a animales y humanos. Esta enfermedad suele ser tratada empíricamente debido a su prevalencia en zonas precarias sin saneamiento básico. El uso de plantas medicinales en las sociedades menos industrializadas ha sido uno de los principales recursos terapéuticos disponibles. Considerando la necesidad de utilizar estos recursos naturales para combatir la leptospirosis en áreas de vulnerabilidad socioeconómica, este estudio tuvo como objetivo revisar la literatura sobre el uso de plantas con potencial medicinal en el tratamiento de la leptospirosis. Los resultados mostraron que a pesar de que la leptospirosis es una enfermedad común en comunidades que carecen de saneamiento básico y desarrollo económico, el número de estudios sobre el uso de plantas con potencial medicinal es escaso. La mayoría de estos estudios provienen de India, y todas las plantas investigadas entre 2012 y 2020 tuvieron acción antileptospirales.

Bioprospecting of pods of Moringa oleifera Lam. as novel antibacterial agent- Supplementary Data

In the treatment of bacterial diseases, increasing resistance to traditional chemotherapeutics has drawn the necessity for substitute remedies. In this context, here, we evaluated the bactericidal activity of pods of Moringa oleifera Lam., an ethno medicinal plant, against eight pathogenic bacterial strains, both Gram positive (Bacillus licheniformis, B. mycoides, B. subtilis and Staphylococcus aureus) and Gram negative (Escherichia coli, Pseudomonas aeruginosa, P. fluorescens and P. putida). Different organic solvent extracts, like ethyl acetate, acetone and alcohol, of pods of M. oleifera were examined for bactericidal activity against test microorganisms. Minimum inhibitory concentration, chromatographic analyses along with infrared spectroscopy, gas chromatography-mass spectroscopy and nuclear magnetic resonance spectroscopy was carried out for chemical characterization of active ingredient responsible for antibacterial activity. Both the Gram positive and Gram negative organisms showed variable sensitivity to different solvent extracts of M. oleifera pods. Ethyl acetate extracts showed maximum antibacterial activity with MIC value ranging from 1.30 to 4.10 mg/mL. IR analysis provided preliminary information about the amines, amides, aromatics and sulphur containing compounds of the active ingredient. GC-MS and NMR analyses indicated the presence of principal bioactive antibacterial compound 2-(benzoylsulfanyl)-1,3- thiazol,4-yl, benzoate with molecular formula C17H11NO3S2 from ethyl acetate extract of M. oleifera pods. The study concludes that the compound 2-(benzoylsulfanyl)-1,3-thiazol,4-yl, benzoate from ethyl acetate extract of pods of M. oleifera possess the antibacterial activity against the tested strains.

Bioprospecting of pods of Moringa oleifera Lam. as novel antibacterial agent

In the treatment of bacterial diseases, increasing resistance to traditional chemotherapeutics has drawn the necessity for substitute remedies. In this context, here, we evaluated the bactericidal activity of pods of Moringa oleifera Lam., an ethno medicinal plant, against eight pathogenic bacterial strains, both Gram positive (Bacillus licheniformis, B. mycoides, B. subtilis and Staphylococcus aureus) and Gram negative (Escherichia coli, Pseudomonas aeruginosa, P. fluorescens and P. putida). Different organic solvent extracts, like ethyl acetate, acetone and alcohol, of pods of M. oleifera were examined for bactericidal activity against test microorganisms. Minimum inhibitory concentration, chromatographic analyses along with infrared spectroscopy, gas chromatography-mass spectroscopy and nuclear magnetic resonance spectroscopy was carried out for chemical characterization of active ingredient responsible for antibacterial activity. Both the Gram positive and Gram negative organisms showed variable sensitivity to different solvent extracts of M. oleifera pods. Ethyl acetate extracts showed maximum antibacterial activity with MIC value ranging from 1.30 to 4.10 mg/mL. IR analysis provided preliminary information about the amines, amides, aromatics and sulphur containing compounds of the active ingredient. GC-MS and NMR analyses indicated the presence of principal bioactive antibacterial compound 2-(benzoylsulfanyl)-1,3- thiazol,4-yl, benzoate with molecular formula C17H11NO3S2 from ethyl acetate extract of M. oleifera pods. The study concludes that the compound 2-(benzoylsulfanyl)-1,3-thiazol,4-yl, benzoate from ethyl acetate extract of pods of M. oleifera possess the antibacterial activity against the tested strains.

Design and Therapeutic Potential of 2,5-substituted diphenyl-1,3,4-oxadiazole Derivatives

In the present study, new class of 2,5-substituted diphenyl-1,3,4-oxadiazole derivatives were developed by combining substituted aromatic acids with hydrazine hydrate in the presence of POCl3 reagent under various reaction conditions. The compounds were also evaluated for their antimicrobial potential against some bacteria (E. coli and S. aureus) and fungi (C. albicans and A. Niger). As the result of the newly synthesized compounds were characterized as 2-(4-chlorophenyl) compounds-5-(4-nitrophenyl)-1,3,4-oxadiazole (13), 2-(4-methylphenyl)-5-(4-nitrophenyl)-1,3,4-oxadiazole (16), 2-(4-chlorophenyl)-5-(4-methoxyhenyl)-1,3,4-oxadiazole (17), 4-[5-(4-methoxyphenyl)-1,3,4-oxadiazol-2-yl]phenol (18), and 2-(4-chlorophenyl)-5-(2,4-dichlorophenyl)-1,3,4-oxadiazole (25). The results also revealed that these compounds have good potential to inhibit microbes. It may be concluded that oxadiazole nucleus may be a profitable source for the synthesis of drugs against infectious diseases.

Keratinase mediated fabrication and partial characterization of gold nanoparticles and its antibacterial potential

Keratinase is mainly involved in recycling of keratin waste. Of late, researchers extended its application to nanotechnology. In the present study, we have made an attempt to fabricate and characterize gold nanoparticles using crude keratinase enzyme from Serratia ficaria and also study their biological application, particularly antibacterial activity. The formation of gold nanoparticles (AuNPs) was first verified by UV-Visible Spectroscopy. FTIR spectra confirmed the presence of responsible secondary metabolites for stabilization of nanoparticles. The morphological characteristics and particle size of synthesized nanoparticles were analyzed. The AuNPs showed significant antibacterial activity against Klebsiella pneumonia, Bacillus cereus and Staphylococcus aureus. The highest radical scavenging activity, 60.62% for AuNPs was observed at 500 µg/mL. Results of this study reveals significance of keratinase application in nano-based biological applications.

Potential of natural products containing 3-acyl tetramic acid as antibacterial precursors / 药学学报

The natural products containing 3-acyl tetramic acid units have a large number of complex and diverse structures, showing a variety of biological activities such as antibacterial, antiviral, anti-tumor and so on, especially antibacterial activity which are regarded as a potential reservoir of new antibiotics. In this paper, the antibacterial activities of various natural products containing 3-acyl tetramic acids and the new research hotspots and directions are reviewed.

Green synthesis of gold nanoparticles from Sophora flavescens extract and their antibacterial effect against some pathogenic bacteria

Aims@#The current study was aimed to evaluate the antibacterial activity of biogenic synthesized golden nanoparticles from Sophora flavescens Aiton roots aqueous extract against multidrug-resistant (MDR) clinical bacterial isolates.@*Methodology and results@#The green synthesis of gold nanoparticles (AuNPs) was accomplished using S. flavescens roots aqueous extract and examined using many accepted techniques. The antibacterial activity of S. flavescens extract and the aqueous AuNPs at concentrations (7% and 9%) ppm were investigated against two clinical MDR bacteria, including Gram-positive (Staphylococcus aureus) and Gram-negative bacteria (Pseudomonas aeruginosa). The findings demonstrate inhibitory activity against the selected MDR bacterial isolates for the aqueous extract of S. flavescens and the aqueous AuNPs noted by the significant decrease in the number of bacteria after treatment with highly significant differences (P≤0.01) compared to the untreated control.@*Conclusion, significance and impact of study@#Sophora flavescens root extracts and their biosynthesized AuNPs with antibacterial activity may find broad applications in fighting MDR pathogenic bacteria and therapeutic manufacturing.

Comparative antibacterial activity and stability of Andrographis paniculata herbal mouthwash and commercial mouthwashes

Aims@#Chemical mouthwash has been used for ages as one of the oral hygiene practices, but due to its side effects, mouthwash formulated from plants has become a better alternative. Andrographis paniculata (AP) is an herb plant known for its antibacterial effects. Thus, this study was aimed to compare the antibacterial activity of AP with commercial mouthwash and to observe the stability of mouthwash formulated from AP.@*Methodology and results@#Aqueous extract of AP was used to prepare herbal mouthwash. The antibacterial activity of AP mouthwash and three commercial types of mouthwash, namely Colgate Plax, Oral B and Listerine, were determined by minimum inhibitory concentration (MIC) through broth dilution method and minimum bactericidal concentration (MBC) against selected oral pathogens; Staphylococcus aureus, Streptococcus mutans and Streptococcus sobrinus. The AP mouthwash was stored for six months and a year at three different storages to assess its stability and microbial contamination by the pour and drop plate method. The results indicated that Colgate Plax and AP mouthwash have the best antibacterial activity compared to two other commercial types of mouthwash with an inhibition percentage of 95.96% at 15.63 mg/mL for S. aureus (Colgate Plax) and 168.45% at 62.5 mg/mL for S. aureus, 93.75% at 7.81 mg/mL for S. mutans and 98.51% at 7.81 mg/mL for S. sobrinus (AP mouthwash). The parameters measured remained unchanged during storage except at room temperature, while the pH level ranged from 6.72 to 7.45. The AP mouthwash showed stable sterility throughout the study. @*Conclusion, significance and impact of study@#The AP mouthwash shows good antibacterial activity against oral pathogens and is almost similar to other commercial mouthwashes and stable to be used for up to a year. In addition, it has excellent potential as an alternative herbal mouthwash in treating oral pathogens effectively.

The bactericidal effect of green macroalgae Cladophora sp. from freshwater toward Gram-negative and Gram-positive bacteria

Aims@#The development of new antimicrobial agents towards multidrug-resistant bacteria is one of the most significant challenges facing the healthcare system today. The continuous increase of antimicrobial resistance rates worldwide is a significant threat to public health. Therefore, this study aimed to investigate the antibacterial effect of filamentous macroalgae Cladophora sp. The sample was collected from an Algerian fountainhead of fresh water. A crude hydromethanolic extract (methanol-water) was tested against two standard Gram-negative bacteria: Escherichia coli ATCC25922 and Pseudomonas aeruginosa ATCC27853, and two standard Gram-positive bacteria: Staphylococcus aureus ATCC25923 and Enterococcus faecalis ATCC 2921. @*Methodology and results@#The antibacterial effect of the hydromethanolic extract of Cladophora sp. was investigated using the well diffusion method to determine the inhibitory diameters and the dilution methods to determine the minimum inhibitory concentration (MIC) and the bactericidal inhibitory concentration (MBC). The results indicated that the hydromethanolic extract of Cladophora sp. is more effective towards Gram-positive bacteria, with a significant effect on S. aureus ATCC 25923, where an inhibitory diameter of 35 mm was recorded. For the Gram-negative, E. coli ATCC25922 was more susceptible with inhibitory diameters of 46 mm, followed by P. aeruginosa ATCC 27853 with 28 mm. The MIC value of hydromethanolic extract of Cladophora sp. was 50 µg/mL for Gram-positive bacteria (S. aureus ATCC25923 and E. faecalis ATCC29212). However, it was 100 µg/mL for Gram-negative bacteria (E. coli ATCC25922 and P. aeruginosa ATCC 27853). The best bactericidal effect was observed with Gram-positive with an MBC of 100 µg/mL. The MBC for Gram-negative bacteria was 150 µg/mL. @*Conclusion, significance and impact of study@#The Cladophora sp. macroalgae represent a potential source of bioactive compounds, which could be used in the management and treatment of various microbial infections.

Studies on the biodiversity of endophytic fungi from Ruta graveolens and screening for their antimicrobial activities

Aims@#The main objective of the present study was to study the diversity of endophytic fungi from Ruta graveolens, an important medicinal plant. The alkaloids produced by this plant have been used in many medical applications. The endophytic fungi that inhabit the plants are also recognized as rich sources of secondary metabolites. This study was aimed to isolate, identify and study the diversity of endophytic fungi in R. graveolens and to screen the isolates for their antimicrobial activities. @*Methodology and results @#A total of 12 different fungal genera were isolated from R. graveolens collected from various sites in and around Bangalore. The species richness and colonizing frequency of endophytic fungi in this plant are comparatively less than other plants. This may be due to the secretion of the plant's phytochemicals, as it has antimicrobial activity and more than 120 phytochemicals in it. Screening of antimicrobial activity of all 10 isolates was done by agar well diffusion method, of which 80% of the fungal isolates could produce antimicrobials. @*Conclusion, significance and impact of study @#To conclude R. graveolens being a good medicinal plant along with its rich source of endophytes and their medicinal properties, can be exploited for the therapeutic applications.

Anti-MDR bacterial activity of bacteria associated with sea sponge of Amphimedon sp. from Karimunjawa Island, Central Java, Indonesia

Aims@#The aim of this study was to evaluate the antibacterial activity of bacteria associated with sea sponge Amphimedon sp. against multi-drug resistant (MDR) bacteria that cause wound infections.@*Methodology and results @#The antibacterial activity was evaluated by the overlay method. Identification of active bacterial symbionts was carried out using the 16S rRNA gene sequence-based method of bacterial identification. The results suggest that one of nine isolates had antibacterial activity against MDR bacteria. Isolate Z9VIII was identified as Bacillus subtilis and demonstrated robust antibacterial activity against bacteria: MRSA (11 mm), MDR-AB (17 mm) and CRPA (12 mm). @*Conclusion, significance and impact of study@#This study concludes that the one of the bacterial species associated with the sea sponge of Amphimedon sp. was B. subtilis, which has the potential as antibacterial agent against MDR bacteria.