Antioxidant and antibacterial activities of bark extracts from Commiphora berryi and Commiphora caudata

This study investigates the in vitro antioxidant and antimicrobial activities of eight extracts obtained from the dried barks of Commiphora berryi and Commiphora caudata (Burseraceae). The radical scavenging activity was assessed by 1,1-diphenyl-2-picryl hydrazyl (DPPH) and nitric oxide assays. The methanolic extracts of C. berryi and C. caudata showed significant DPPH radical scavenging activity, with IC?? values of 26.92 and 21.16?μg?mL?1, respectively, and low radical scavenging activity against the nitric oxide assay. The antimicrobial activity of the plants was tested against the Gram-positive and Gram-negative bacteria. The ethyl acetate, chloroform and petroleum ether extracts of C. berryi showed good antibacterial activity against Pseudomonas aeruginosa, with a minimum inhibitory concentration (MIC) of 0.26?mg?mL?1, whereas the ethyl acetate and methanol extracts of C. caudata showed moderate antimicrobial activity with an MIC of more than 2.0?mg?mL?1 against P. aeruginosa compared to the petroleum ether and chloroform extracts, which showed an MIC of 1.1?mg?mL?1. The methanolic extracts of C. berryi and C. caudata also showed moderate cytotoxic activity against a human mammary carcinoma cell line (MCF-7), with values IC?? of 82.6 and 88.4?μg?mL?1, respectively.     

In vitro hypoglycemic and antimicrobial activities of Senecio leucanthemifolius Poiret

This study reports on the alpha-amylase inhibitory and antimicrobial activities of Senecio leucanthemifolius Poiret. Extracts of S. leucanthemifolius were tested for their antimicrobial and antifungal activities against seven different pathogenic microorganisms using the microdilution technique. The ethyl acetate extract exhibited a strong antibiotic activity against Staphylococcus aureus with a MIC value of 31.25 microg mL(-1), while the n-hexane extract showed a significant activity against dermatophytic fungi. S. leucanthemifolius extracts were tested also for their potential hypoglycemic activity through the in vitro inhibition of alpha-amylase. The dichloromethane extract inhibited alpha-amylase with a value of 56.6% at 0.05 mg mL(-1) and the n-butanol extract showed a value of 89.2% at 1 mg mL(-1).     

In-vitro antibacterial properties of crude aqueous and n-hexane extracts of the husk of Cocos nucifera

The increasing numbers of cases of antibiotic resistance among pathogenic bacteria such as Vibrio species poses a major problem to the food and aquaculture industries, as most antibiotics are no longer effective in controlling pathogenic bacteria affecting these industries. Therefore, this study was carried out to assess the antibacterial potentials of crude aqueous and n-hexane extracts of the husk of Cocos nucifera against some selected Vibrio species and other bacterial pathogens including those normally implicated in food and wound infections. The crude extracts were screened against forty-five strains of Vibrio pathogens and twenty-five other bacteria isolates made up of ten Gram positive and fifteen Gram negative bacteria. The aqueous extract was active against 17 of the tested bacterial and 37 of the Vibrio isolates; while the n-hexane extract showed antimicrobial activity against 21 of the test bacteria and 38 of the test Vibrio species. The minimum inhibitory concentrations (MICs) of the aqueous and n-hexane extracts against the susceptible bacteria ranged between 0.6-5.0 mg/mL and 0.3-5.0 mg/mL respectively, while the time kill study result for the aqueous extract ranged between 0.12 Log?? and 4.2 Log?? cfu/mL after 8 hours interaction in 1 x MIC and 2 x MIC. For the n-hexane extract, the log reduction ranged between 0.56 Log?? and 6.4 Log?? cfu/mL after 8 hours interaction in 1 x MIC and 2 x MIC. This study revealed the huge potential of C. nucifera extracts as alternative therapies against microbial infections.     

In-vitro antagonistic characteristics of crude aqueous and methanolic extracts of Garcinia kola (Heckel) seeds against some Vibrio bacteria

The methanolic and aqueous extracts of Garcinia kola seeds were screened for their anti-Vibrio activities against 50 Vibrio isolates obtained from wastewater final effluents in the Eastern Cape Province, South Africa. The crude extracts at 10 mg/mL exhibited appreciable inhibitory activities against most of the test Vibrio isolates, with zones of inhibition ranging from 10-19 mm for methanol extract and 8-15 mm for the aqueous extracts. The minimum inhibitory concentrations (MIC) of the methanol extract varied from 0.313 to 2.5 mg/mL while that for the aqueous extract was 10 mg/mL for all the susceptible Vibrio isolates. Rate of kill assay of the methanolic extracts against three selected Vibrio species showed bacteriostatic activities against all of them achieving 58% and 60% (Vibrio vulnificus AL042); 68% and 69% (Vibrio parahaemolyticus AL049); and 70% and 78% (Vibrio fluvialis AL040) killing of the test bacteria at 3× and 4 ×MIC values, respectively, after 2 h exposure time. We conclude that Garcinia kola seeds hold promise as a potential source of therapeutic compounds of relevance in Vibrio infections management.     

Antimicrobial activity of Blumea balsamifera (Lin.) DC. extracts and essential oil

Leaves of Blumea balsamifera (Lin.) DC. are used in traditional Thai and Chinese medicine for the treatment of septic wounds and other infections. In this study, the essential oil, hexane, dichloromethane and methanol extracts of these leaves were evaluated for antibacterial and antifungal activities using the disc diffusion assay and agar microdilution method. The essential oil was the most potent, with a minimum inhibitory concentration (MIC) of 150?μg?mL?1 against Bacillus cereus and an MIC of 1.2?mg?mL?1 against Staphylococcus aureus and Candida albicans. Activity was also detected from the hexane extract against Enterobacter cloacae and S. aureus. Minimum bactericidal and fungicidal concentrations were typically equal to or two-fold higher than the MICs for both extracts, indicating microbicidal activity. The present data show that B. balsamifera extracts have activity against various infectious and toxin-producing microorganisms. This plant's active constituents could potentially be developed for use in the treatment and/or prevention of microbial disease.     

Antimicrobial activity and phenolic content of natural site and micropropagated Limonium avei (De Not.) Brullo & Erben plant extracts

This study reported the antimicrobial activity and phenolic content of natural site and micropropagated Limonium avei (De Not.) Brullo & Erben inflorescences. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of ethanolic extracts were determined according to the Clinical Laboratory Standards Institute guidelines. Individual phenolic acids and flavonoids were detected by a high performance liquid chromatography (HPLC-DAD) method. The samples showed a comparable antimicrobial activity, although the natural site extract possessed the lower MIC values. The best activity was detected against Gram-positive bacteria, such as Staphylococcus aureus including methicillin resistant strains (MIC and MBC values ranging from 7.81 to 62.50?μg?mL(-1) and from 500 to 2000?μg?mL(-1) respectively). In contrast, a low activity was found on Gram-negative bacteria and Candida albicans. The HPLC-DAD analysis revealed ten phenolic acids and four flavonoids with a major amount of m-coumaric acid, naringin and quercetin in the natural site extract.     

Antimicrobial investigation of Linum usitatissimum for the treatment of acne

Light petroleum, dichloromethane and methanolic extracts of Linum usitatissimum were investigated using GC/MS. The main components of three sequential extracts were methyl linolenate (11.9-33.9%) and methyl linoleate (3.4-9.1%). Components possessing antimicrobial activity against acne causing bacteria, namely alpha-linolenic acid (7.0 -7.1%), alpha-terpinene (1.7-3.1%), terpinen-4-ol (1.3-4.6%), 4-cymene (1.6-7.1%) and alpha-pinene (1.1%), were found in varying amounts. Antimicrobial screening indicated that the light petroleum extract was more active against aerobic and anaerobic test strains with a MIC value of 1.25 mg/mL and a MBC of 2.5 mg/mL against S. aureus and P. acnes. A MIC of 2.5 mg/mL was observed against S. epidermidis.     

Phytochemical profiling and evaluation of modified resazurin microtiter plate assay of the roots of Trillium govanianum

Abstract

Trillium govanianum Wall. ex D. Don (Melanthiaceae alt. Trilliaceae), is native to the Himalayas. The present study, for the first time, was undertaken to explore the antimicrobial potential, to determine the minimum inhibitory concentration (MIC) values of the methanol extract of the roots of Trillium govanianum and its solid phase extraction (SPE) fractions by using resazurin microtiter assay (REMA) against Gram positive and Gram negative bacterial registered strains and to carry out phytochemical analysis. The remarkable amount of gallic acid equivalent phenolic and quercetin equivalent flavonoid content was manifested by MeOH extract (20.27?±?3.03?mg GAE/g DW and 9.25?±?0.50?mg QE/g DW respectively). The GC/MS analysis revealed the presence saturated and unsaturated components. Considerable level of antibacterial potential against Gram-positive bacteria (MIC: 2.5-0.009?mg/mL) than against Gram-negative bacteria (MIC: 2.5-0.165?mg/mL) were observed. The use of microtiter plates has the advantage of lower cost, fast and quantitative results.     

In vitro antibacterial and time-kill assessment of crude methanolic stem bark extract of Acacia mearnsii de wild against bacteria in shigellosis

Shigellosis is an important cause of worldwide morbidity and mortality among young children and old people for which treatment with antimicrobial agents is limited. Hence, the need for curative potentials obtainable from medicinal plants becomes inevitable. This study was carried out to assess the antibacterial potentials of crude methanolic extract of the stem bark of Acacia mearnsii against some selected bacteria of clinical importance in shigellosis. The bacteria were inhibited by the extract to produce concentration dependent inhibition zones. The extract exhibited a varied degree of antibacterial activity against all the tested isolates. The MIC values for Gram negative (0.0391-0.3125) mg/mL and those of Gram positive bacteria (0.0781-0.625) mg/mL indicated that the Gram negative bacteria were more inhibited by the extract than the Gram positive bacteria. Average log reduction in viable cell count in time-kill assay ranged between -2.456 Log?? to 2.230 Log?? cfu/mL after 4 h of interaction, and between -2.921 Log?? and 1.447 Log?? cfu/mL after 8 h interaction in 1× MIC and 2× MIC of the extract. The study provided scientific justification for the use of the crude methanolic extract from the stem bark of A. mearnsii in shigellosis. The degree of the antibacterial activity indicated that the crude extract is a potential source of bioactive compounds that could be useful for the development of new antimicrobial agents capable of decreasing the burden of drug resistance and cost of management of diseases of clinical and public health importance in South Africa.     

Chemical composition and antimicrobial activity of the essential oil of the leaves of Feronia elephantum (Rutaceae) from north west Karnataka

The essential oil of the leaves of Feronia elephantum Corr. was analyzed by gas chromatography and gas chromatography/mass spectrometry. The main constituents were beta-pinene (28.4%), Z-anethole (22.1%), methyl chavicol (12.0%) and E-anethole (8.1%), among thirty-three identified compounds, which represented 92.6% of the total oil. The antimicrobial activity was tested against five Gram-positive and eight Gram-negative bacteria, and four fungi. The oil was active against Micrococcus luteus (Gram-positive bacterium), Proteus mirabilis (Gram-negative bacterium), Penicillium chrysogenum and Aspergillus niger (fungi) with MIC values of 0.31 +/- 0.06, 0.52 +/- 0.10, 0.20 +/- 0.50 and 0.26 +/- 0.52 mg/mL, respectively.     

Chemical composition and antimicrobial activity of the essential oil of Anthemis altissima L. var. altissima

The essential oil obtained from the flowering parts of Anthemis altissima L. var. altissima was analysed by gas chromatography and gas chromatography mass spectroscopy. In this study, 34 compounds representing 98.76% of the essential oil were identified. The main components were α-terpineol (26.42%), β-pinene (9.23%), cis-chrysanthenyl acetate (6.30%), globulol (5.36%), n-tricosane (4.41%), terpinen-4-ol (4.08%) and 1,8 cineole (3.84%). Antibacterial activities of the essential oil and its two major components (α-terpineol and β-pinene) were determined using microdilution method against both Gram-positive (Staphylococcus aureus, Bacillus subtilis, Staphylococcus epidermidis) and Gram-negative (Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumoniae) bacteria. The essential oil showed a broad-spectrum antibacterial activity (MICs ranged from 3.13 to 6.25?μL?mL(-1)). It was found that α-terpineol with minimum inhibitory concentration (MIC) values of the range 0.87-1.56?μL?mL(-1) was a more potent antibacterial agent than β-pinene with MIC values of the range 1.56-6.25?μL?mL(-1). All of them, the essential oil, β-pinene and α-terpineol, were more effective against Gram-positive bacteria than Gram-negative ones.     

Antimicrobial activity of the methanolic bark extract of Holarrhena pubescens (Buch. Ham), its fractions and the pure compound conessine

The antimicrobial activity of the methanolic extract of the bark of Holarrhena pubescens, its fractions, and conessine, a steroidal alkaloid, was determined against various bacteria and fungi using the agar diffusion method. They were all found to possess significant activity against some of the bacteria tested. The alkaloidal fraction and conessine also exhibited marginal activity against some of the fungi tested. The minimum inhibitory concentration (MIC) value of conessine was determined against various bacteria, and the highest activity was seen against Micrococcus luteus ATCC 9341 (MIC: 15.6?μg per disc).     

Antimicrobial and antioxidative activities of bioactive constituents from Hydnophytum formicarum Jack

Hydnophytum formicarum Jack. (Rubiaceae) is a medicinal plant whose tubers possesses cardiovascular, anti-inflammatory and antiparasitic effects and have been used for the treatment of hepatitis, rheumatism and diarrhea. Herein we report the isolation of its active constituents and the testing of their antimicrobial activity against 27 strains of microorganisms using an agar dilution method and of their antioxidative activity using the DPPH and SOD assays. The results show that the crude hexane, dichloromethane, ethylacetate and methanol extracts exert such activities. Particularly, the crude ethyl acetate extract exhibits antigrowth activity against many Gram-positive and Gram-negative bacteria with MIC 256 microg/mL. Shewanella putrefaciens ATCC 8671 is completely inhibited at a lower MIC (128 microg/mL). Interestingly, Corynebacterium diphtheriae NCTC10356 is inhibited by all the tested extracts. Significantly, the ethyl acetate extract is also the most potent antioxidant, showing 83.31% radical scavenging activity with IC50 8.40 microg/mL in the DPPH assay. The other extracts display weak to moderate antioxidative activities, ranging from 28.60-56.80% radical scavenging. The SOD assay shows that methanol extract exhibits the highest activity (74.19% inhibition of superoxide radical). The dichloromethane and ethyl acetate extracts display comparable SOD activity. The promising bioactivities of the crude ethyl acetate extract guided the first isolation of bioactive flavonoid and phenolic compounds: isoliquiritigenin (2), protocatechualdehyde(3), butin (4) and butein (5) from this species. Their structures have been fully established by 1D and 2D NMR. In addition, stigmasterol was isolated from the crude hexane and dichloromethane extracts. The antimicrobial and cytotoxic activities of compounds 3-5 were evaluated. The tested compounds were inactive against HuCCA-1 and KB cell lines,showing ED50> 10 microg/mL. Protocatechualdehyde (3) completely inhibits the growth of Plesiomonas shigelloides with MIC 相似文献   

Comparison of hydrodistillation and headspace solid-phase microextraction techniques for antibacterial volatile compounds from the fruits of Seseli libanotis

The volatile compounds from the fruits of Seseli libanotis, wild-growing in Poland, were obtained by hydrodistillation (HD) and headspace solid-phase microextraction techniques (HS-SPME) and analyzed using GC-MS. A total of 58 components were identified. The most abundant compounds were sabinen and beta-phellandrene. MIC (minimal inhibitory concentration) and MBC (minimal bactericidal concentration) values for the essential oil against reference bacterial strains and clinical S. aureus isolates were determined. The essential oil showed better antibacterial activity against the Gram-positive bacteria (MICs between 0.15 to 1.25 mg/mL) when compared with Gram-negative bacteria (MICs between 1.25 to 2.5 mg/mL). The low values of the MBC/MIC ratio suggest that the examined oil behaved as a bactericidal agent.     

Chemical constituents, antioxidant and antimocrobial activity of essential oil of Pogostemon paniculatus (Willd.)

The essential oil extracted from the leaves of Pogostemon paniculatus (Willd.) Benth. (Lamiaceae), was analysed by gas chromatography-mass spectrometry (GC-MS). Nineteen compounds constituting 85.36% of the total oil were identified in the oil. Patchouli alcohol (30.65%), α-guaiene (10.67%), β-guaiene (9.09%), caryophyllene (8.64%), eicosene (5.27%) were the major constituents present. The essential oil was analysed for antimicrobial activity by disc diffusion assay and minimum inhibition concentration against six bacteria and three fungi. Results showed inhibitory activity against some of the tested microorganisms. The essential oil was also tested for the DPPH free-radical scavenging activity and had an inhibitory concentration (IC(50)) value of 18.5?μg?mL(-1).     

Evaluation of resazurin microtiter plate assay and HPLC- photodiode array analysis of the roots of Asparagus adscendens

Asparagus adscendens Roxb. (Asparagaceae), is native to the Himalayas. The present study, for the first time, was undertaken to explore the antimicrobial potential, to determine the minimum inhibitory concentration (MIC) values of the methanol extract of the roots of A. adscendens and its solid-phase extraction (SPE) fractions using resazurin microtitre assay against Gram-positive and negative bacterial-registered strains and to carry out HPLC-photodiode array analysis of the SPE fractions. The methanol extract and all SPE exhibited considerable level of antibacterial potential against Gram-positive bacteria (MIC: 2.5–0.009 mg/mL) than against Gram-negative bacteria (MIC: 1.25–2.5 mg/mL). The use of microtitre plates has the advantage of lower cost, fast and quantitative results. Like other Asparagus species, the presence of phenolic compounds in all SPE fractions was evident in the HPLC-PDA data.     

Composition, antioxidant and antimicrobial activities of the leaf essential oil of Machilus japonica from Taiwan

The chemical composition, and antioxidant and antimicrobial activities of the essential oil isolated from the leaf of Machilus japonica from Taiwan have been investigated. The essential oil from the fresh leaves was isolated using hydrodistillation in a Clevenger-type apparatus, and characterized by GC-FID and GC-MS. A total of 97 compounds were identified, representing 100% of the oil. The main components identified were alpha-phellandrene (14.5%), alpha-pinene (12.8%), thymol (12.6%), beta-pinene (8.3%), alpha-terpineol (6.5%) and carvacrol (6.0%). The antioxidant activity of the oil was tested by the DPPH (2,2-diphenyl-1-picrylhydrazyl) free radical scavenging capability test. The results showed that the IC50 was 51.8 microg/mL. The antimicrobial activity of the oil was tested by the disc diffusion and micro-broth dilution methods against ten microbial species. The oil exhibited strong growth suppression against Gram-positive bacteria and yeast, with inhibition zones of 48-54 mm and MIC values of 16.12-32.25 microg/mL, respectively. For the antioxidant and antimicrobial activities of the oil, the active source compounds were determined to be thymol and carvacrol.     

Composition, antioxidant, antimicrobial and anti-wood-decay fungal activities of the twig essential oil of Taiwania cryptomerioides from Taiwan

This study investigated the chemical composition, antioxidant, antimicrobial and anti-wood-decay fungal activities of the essential oil isolated from the twigs of Taiwania cryptomerioides from Taiwan. The essential oil was isolated using hydrodistillation in a Clevenger-type apparatus, and characterized by GC-FID and GC-MS. A total of 35 compounds were identified, representing 100% of the oil. The main components identified were alpha-cadinol (45.9%), ferruginol (18.9%) and beta-eudesmol (10.8%). The antioxidant activity of the oil was tested by the DPPH (2,2-diphenyl-1-picrylhydrazyl) free radical scavenging capability test. The results showed an IC50 of 90.8 +/- 0.2 microg/mL. The active source compound was ferruginol. The antimicrobial activity of the oil was tested by the disc diffusion and micro-broth dilution methods against ten microbial species. The oil exhibited strong growth suppression against Gram-positive bacteria and yeast with inhibition zones of 45-52 mm and MIC values of 31.25-62.5 microg/mL, respectively. The anti-wood-decay fungal activity of the oil was also evaluated. The oil demonstrated excellent activity against four wood-decay-fungal species. For the antimicrobial and anti-wood-decay fungal activities of the oil, the active source compounds were determined to be alpha-cadinol, beta-eudesmol and ferruginol.     

An antimicrobial compound isolated from Cinnamomum iners leaves with activity against methicillin-resistant Staphylococcus aureus

This study was designed to investigate the antimicrobial activity of Cinnamomum iners standardized leave methanolic extract (CSLE), its fractions and isolated compounds. CSLE and fractions were subjected to disc diffusion, minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) tests using different Gram positive and Gram negative bacteria and yeast. Within the series of fractions tested, the ethyl acetate fraction was the most active, particularly against methicillin resistant Staphylococcus aureus (MRSA) and Escherichia coli, with MIC values of 100 and 200 μg/mL, respectively. The active compound in this fraction was isolated and identified as xanthorrhizol [5-(1, 5-dimethyl-4-hexenyl)-2-methylphenol] by various spectroscopic techniques. The overall results of this study provide evidence that Cinnamomum iners leaves extract as well as the isolated compound xanthorrhizol exhibit antimicrobial activity for both Gram negative and Gram positive pathogens, especially against MRSA strains.     

Composition and antimicrobial activity of the essential oil of Heracleum thomsonii (Clarke) from the cold desert of the western Himalayas

Volatile oil composition of hydro-distilled (HD) and supercritical carbon dioxide (SC-CO(2)) essential oil of freshly collected aerial parts of Heracleum thomsonii (Umbeliferae) from the western Himalayas was studied by GC-FID and GC-MS. Results revealed qualitative and quantitative dissimilarity in the composition of hydro-distilled and SC-CO(2) extracted oils. Nineteen constituents, which accounted for 89.32% of total constituents in HD oil, represented by limonene (4.31%), (Z)-β-ocimene (3.69%), terpinolene (22.24%), neryl acetate (36.19%), nerol (9.51%) and p-cymene-8-ol (2.61%) were identified. In SC-CO(2) extracted oil, 24 constituents representing 89.95% of total constituents were identified. Terpinolene (5.08%), germacrene D (2.17%), neryl acetate (51.62%), nerol (9.78%), geranyl acetate (2.06%), α-bisabolol (2.48%) and 1-nonadecanol (4.96%) were the dominating constituents. In?vitro antimicrobial activity of hydro-distilled oil was conducted against microrobial strains including two Gram-positive (Staphylococcus aureus and Bacillus subtilis) and five Gram-negative (Burkholderia cepacia, Escherichia coli, Enterobacter cloacae, Klebseilla pneumoniae and Pseudomonas aeruginosa) bacteria as well as seven fungi (Candida albicans, Issatchenkia orientalis, Aspergillus flavus, Aspergillus niger, Aspergillus parasiticus, Aspergillus sydowii and Trichophyton rubrum) using broth microdilution method. The results of bioassay showed that the oil exhibited moderate to high antimicrobial activity against fungi C. albicans (MIC 625 μg?ml(-1)), A. parasiticus (MIC 312.5 μg?ml(-1)), A. sydowii (MIC 312.5 μg?ml(-1)), T. rubrum (MIC 625 μg?ml(-1)), Gram-positive bacteria B. subtilis (MIC 625?μg?ml(-1)) and Gram-negative bacteria P. aeruginosa (MIC 312.5 μg?ml(-1)).