Okundoperoxide (1) was isolated by bioassay-guided fractionation of extracts from Scleria striatinux (syn. S. striatonux) (Cyperaceae). The compound contains a cyclic endoperoxide structural moiety and possesses moderate antimalarial activity.
Through bioassay-guided fractionation of the extracts from the aerial parts of the Chinese herb Hypericum japonicum Thunb. Murray, Isojacareubin (ISJ) was characterized as a potent antibacterial compound against the clinical methicillin-resistant Staphylococcus aureus (MRSA). The broth microdilution assay was used to determine the minimal inhibitory concentrations (MICs) and minimal bactericidal concentrations (MBCs) of ISJ alone. The results showed that its MICs/MBCs ranged from 4/16 to 16/64 μg/mL, with the concentrations required to inhibit or kill 50% of the strains (MIC50/MBC50) at 8/16 μg/mL. Synergistic evaluations of this compound with four conventional antibacterial agents representing different types were performed by the chequerboard and time-kill tests. The chequerboard method showed significant synergy effects when ISJ was combined with Ceftazidime (CAZ), Levofloxacin (LEV) and Ampicillin (AMP), with the values of 50% of the fractional inhibitory concentration indices (FICI50) at 0.25, 0.37 and 0.37, respectively. Combined bactericidal activities were also observed in the time-kill dynamic assay. The results showed the ability of ISJ to reduce MRSA viable counts by log10CFU/mL at 24 h of incubation at a concentration of 1 × MIC were 1.5 (LEV, additivity), 0.92 (CAZ, indifference) and 0.82 (AMP, indifference), respectively. These in vitro anti-MRSA activities of ISJ alone and its synergy with conventional antibacterial agents demonstrated that ISJ enhanced their efficacy, which is of potential use for single and combinatory therapy of patients infected with MRSA.
anti-MRSA activity; Hypericum japonicum; Isojacareubin; MIC; synergy
The rapidly increasing number of available plant genomes opens up almost unlimited prospects for biology in general and molecular phylogenetics in particular. A recent study took advantage of this data and identified a set of nuclear genes that occur in single copy in multiple sequenced angiosperms. The present study is the first to apply genomic sequence of one of these low copy genes, agt1, as a phylogenetic marker for species-level phylogenetics. Its utility is compared to the performance of several coding and non-coding chloroplast loci that have been suggested as most applicable for this taxonomic level. As a model group, we chose Tildenia, a subgenus of Peperomia (Piperaceae), one of the largest plant genera. Relationships are particularly difficult to resolve within these species rich groups due to low levels of polymorphisms and fast or recent radiation. Therefore, Tildenia is a perfect test case for applying new phylogenetic tools.
We show that the nuclear marker agt1, and in particular the agt1 introns, provide a significantly increased phylogenetic signal compared to chloroplast markers commonly used for low level phylogenetics. 25% of aligned characters from agt1 intron sequence are parsimony informative. In comparison, the introns and spacer of several common chloroplast markers (trnK intron, trnK-psbA spacer, ndhF-rpl32 spacer, rpl32-trnL spacer, psbA-trnH spacer) provide less than 10% parsimony informative characters. The agt1 dataset provides a deeper resolution than the chloroplast markers in Tildenia.
Single (or very low) copy nuclear genes are of immense value in plant phylogenetics. Compared to other nuclear genes that are members of gene families of all sizes, lab effort, such as cloning, can be kept to a minimum. They also provide regions with different phylogenetic content deriving from coding and non-coding parts of different length. Thus, they can be applied to a wide range of taxonomic levels from family down to population level. As more plant genomes are sequenced, we will obtain increasingly precise information about which genes return to single copy most rapidly following gene duplication and may be most useful across a wide range of plant groups.
Ethanol extract of Rhodomyrtus tomentosa (Aiton) Hassk. leaf was evaluated for antibacterial activity against 47 clinical isolates of Streptococcus pyogenes. The extract exhibited good anti-S. pyogenes activity against all the tested isolates with similar minimum inhibitory concentration (MIC, 3.91–62.5 μg mL−1) and minimum bactericidal concentration (MBC, 3.91–62.5 μg mL−1) ranges. No surviving cells were detected at 16 h after treatment with 8 × MIC of the extract. The extract-treated cells demonstrated no lysis and cytoplasmic leakage through the bacterial membrane. Electron micrographs further revealed that the extract did not cause any dramatic changes on the treated cells. Rhodomyrtone, an isolated compound, exhibited good anti-S. pyogenes activity (14 isolates), expressed very low MIC (0.39–1.56 μg mL−1) and MBC (0.39-1.56 μg mL−1) values. Rhodomyrtus tomentosa leaf extract and rhodomyrtone displayed promising antibacterial activity against clinical isolates of S. pyogenes.
Our previous work has demonstrated that several plants in the Piperaceae family are commonly used by the Q’eqchi Maya of Livingston, Guatemala to treat amenorrhea, dysmenorrhea, and pain. Extracts of Piper hispidum Swingle (Piperaceae), bound to the estrogen (ER) and serotonin (5-HT7) receptors.
Aim of the study
To investigate the estrogenic and serotonergic activities of P. hispidum extracts in functionalized assays, identify the active chemical constituents in the leaf extract, and test these compounds as agonists or antagonists of ER and 5-HT7.
Materials and methods
The effects of the P. hispidum leaf extracts were investigated in estrogen reporter gene and endogenous gene assays in MCF-7 cells to determine if the extracts acted as an estrogen agonist or antagonist. In addition, the active compounds were isolated using ER- and 5-HT7 receptor bioassay-guided fractionation. The structures of the purified compounds were identified using high-resolution LC-MS and NMR spectroscopic methods. The ER- and 5-HT7-agonist effects of the purified chemical constituents were tested in a 2ERE-reporter gene assay in MCF-7 cells and in serotonin binding and functionalized assays.
Three butenolides including one new compound (1) were isolated from the leaves of P. hispidum, and their structures were determined. Compound 1 bound to the serotonin receptor 5-HT7 with IC50 values of 16.1 and 8.3 μM, respectively, and using GTP shift assays, compound 1 was found to be a partial agonist of the 5-HT7 receptor. The P. hispidum leaf extracts, as well as compounds 2 and 3 enhanced the expression of estrogen responsive reporter and endogenous genes in MCF-7 cells, demonstrating estrogen agonist effects.
Extracts of P. hispidum act as agonists of the ER and 5-HT7 receptors. Compound 1, a new natural product, identified as 9, 10-methylenedioxy-5,6-Z-fadyenolide, was isolated as the 5-HT7 agonist. Compounds 2 and 3 are reported for the first time in P. hispidum, and identified as the estrogen agonists. No inhibition of CYP450 was observed for any of these compounds in concentrations up to 1 μM. These activities are consistent with the Q’eqchi traditional use of the plant for the treatment of disorders associated with the female reproductive cycle.
Piper hispidum; Butenolides; Estrogen agonist; Maya; 9, 10-Methylenedioxy-5, 6-Z-fadyenolide; Serotonin agonist
Aquilaria crassna Pierre ex Lecomte has been traditionally used in Thailand for treatment of infectious diseases such as diarrhoea and skin diseases for a long time. The main objectives of this study were to examine antibacterial activity of the Aquilaria crassna leaf extract against Staphylococcus epidermidis and its underlying mechanism. The antioxidant activity and acute toxicity were studied as well.
Antioxidant activities were examined by FRAP, ABTS and DPPH scavenging methods. Antibacterial activity was conducted using disc diffusion assay and the minimum inhibitory concentration (MIC) was determined by dilution method. The minimum bactericidal concentration (MBC) was reported as the lowest concentration producing no growth of microbes in the subcultures. Morphological changes of the microbe were observed by scanning electron microscopy, while an inhibitory effect on biofilm formation was evaluated by phase contrast microscopic analysis. Bacterial cell wall integrity was assessed by transmission electron microscopy. Acute toxicity was conducted in accordance with the OECD for Testing of Chemicals (2001) guidelines.
The extract exhibited considerable antioxidant activity. Staphylococcus epidermidis was susceptible to the extract with the MIC and MBC of 6 and 12 mg/ml, respectively. The extract caused swelling and distortion of bacterial cells and inhibited bacterial biofilm formation. Rupture of bacterial cell wall occurred after treated with the extract for 24 h. Acute toxicity test in mice showed no sign of toxicity or death at the doses of 2,000 and 15,000 mg/kg body weight.
The aqueous extract of Aquilaria crassna leaves possesses an in vitro antibacterial activity against Staphylococcus epidermidis, with no sign of acute oral toxicity in mice, probably by interfering with bacterial cell wall synthesis and inhibiting biofilm formation.
Aquilaria crassna; Staphylococcus epidermidis; Antioxidant; Anitbacterials; Cell wall; Acute toxicity
Many edible plants are used in Cameroon since ancient time to control microbial infections. This study was designed at evaluating the antibacterial activities of the methanol extracts of ten Cameroonian vegetables against a panel of twenty nine Gram negative bacteria including multi-drug resistant (MDR) strains.
The broth microdilution method was used to determine the Minimal Inhibitory Concentrations (MIC) and the Minimal Bactericidal Concentrations (MBC) of the studied extracts. When chloramphenicol was used as a reference antibiotic, the MICs were also determined in the presence of Phenylalanine-Arginine β-Naphtylamide (PAβN), an efflux pumps inhibitor (EPI). The phytochemical screening of the extracts was performed using standard methods.
All tested extracts exhibited antibacterial activities, with the MIC values varying from 128 to 1024 mg/L. The studied extracts showed large spectra of action, those from L. sativa, S. edule, C. pepo and S. nigrum being active on all the 29 bacterial strains tested meanwhile those from Amaranthus hybridus, Vernonia hymenolepsis, Lactuca.carpensis and Manihot esculenta were active on 96.55% of the strains used. The plant extracts were assessed for the presence of large classes of secondary metabolites: alkaloids, anthocyanins, anthraquinones, flavonoids, phenols, saponins, steroids, tannins and triterpenes. Each studied plant extract was found to contain compounds belonging to at least two of the above mentioned classes.
These results confirm the traditional claims and provide promising baseline information for the potential use of the tested vegetables in the fight against bacterial infections involving MDR phenotypes.
Antibacterial; Gram-negative bacteria; Multi-drug resistant; Extract; Vegetable
Myristica fragrans Houtt is mostly cultivated for spices in Penang Island, Malaysia. The ethyl acetate and ethanol extracts of flesh, mace and seed of Myristica fragrans was evaluated the bactericidal potential against three Gram-positive cariogenic bacteria (Streptococcus mutans ATCC 25175, Streptococcus mitis ATCC 6249, and Streptococcus salivarius ATCC 13419) and three Gram-negative periodontopathic bacteria (Aggregatibacter actinomycetemcomitans ATCC 29522, Porphyromonas gingivalis ATCC 33277, and Fusobacterium nucleatum ATCC 25586). Antibacterial activities of the extracts was determined by twofold serial microdilution, with minimum inhibitory concentrations (MIC) ranging from 1.25 to 640 mg/mL and 0.075 to 40 mg/mL. The minimum bactericidal concentration (MBC) was obtained by subculturing method. Among all extracts tested, ethyl acetate extract of flesh has the highest significant inhibitory effects against Gram-positive and Gram-negative bacteria with mean MIC value ranging from 0.625 to 1.25 ± 0.00 (SD) mg/mL; P = 0.017) and highest bactericidal effects at mean MBC value ranging from 0.625 mg/mL to 20 ± 0.00 (SD) mg/mL. While for seed and mace of Myristica fragrans, their ethanol extracts exhibited good antibacterial activity against both groups of test pathogens compared to its ethyl acetate extracts. All of the extracts of Myristica fragrans did not show any antibacterial activities against Fusobacterium nucleatum ATCC 25586. Thus, our study showed the potential effect of ethyl acetate and ethanol extracts from flesh, seed and mace of Myristica fragrans to be new natural agent that can be incorporated in oral care products.
Peperomia pellucida is popularly known as coraçãozinho in the Brazilian northeast and is used in the treatment of abscesses, furuncles, and conjunctivitis. Our work aimed to determine the term of the development stages and the species cycle in the four seasons of the year (complete development, beginning of bloom, complete bloom, and seed set), verifying the plant's therapeutic profile during the four distinct development phases in order to detect differences in its potency. Pharmacological tests were performed to observe the anti-inflammatory activity.
Phenological observations were accessed for a 12 month-period, from the Brazilian summer of 1999/2000 to fall 2000. On average the plantules' emergence occurred 15 days after seeding. All plantules grew in a similar manner up to 25 days after transplantation in all seasons. Starting on the 25th day, we observed faster growth during spring, with plants reaching a height of about 60 cm after 100 days of transplantation, unlike other seasons, in which plants reached heights of 40, 40, and 35 cm during winter, summer, and fall, respectively. The P. pellucida aqueous extract showed significant anti-inflammatory activity during phenophases 1 and 2 of winter and spring. Depending on the plant's phenophase there was variation in the potency of edema inhibition.
P. pellucida has a phenological cycle of approximately 100 days. It is recommended that the P. pellucida aqueous extract is used as an antiedematogenic only during phenophases 1 and 2 of winter and spring.
To evaluate antibacterial activity of hot and cold ethanol and methanol leaf extracts of Ricinus communis L (R. communis) against Staphylococcus aureus (S. aureus) (NCTC 6571) and Escherichia coli (E. coli) (ATCC 25922).
Leaf powder of R. communis L. was extracted with hot (in Soxhlet) and cold ethanol and methanol, separately. The antibacterial activity of the extracts was determined by agar well diffusion and macro broth dilution methods. The extracts were also subjected to phytochemical analysis.
All the four test extracts showed inhibition on both S. aureus and E. coli. Hot and cold ethanol extracts revealed significantly (P<0.05) higher inhibition on S. aureus than methanol extracts, and the hot ethanol extract had the lowest minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) values (5 mg/mL and 10 mg/mL, respectively). E. coli was highly inhibited by hot extracts of both ethanol and methanol with the MIC and MBC of 40 mg/mL and 80 mg/mL, respectively. Phytochemical analysis revealed the presence of saponins, cardiac glycosides, tannins, flavonoids and terpenoids in all test extracts.
This study demonstrates that the hot and cold methanol and ethanol extracts are potential sources for control of S. aureus and E. coli. Especially, the hot and cold extracts of ethanol are more inhibitive against S. aureus even at lower concentration. Further study is needed to identify the specific bioactive compounds, their mode of action and their nontoxic nature in vivo condition.
Ricinus communis; Antibacterial activity; Staphylococcus aureus; Escherichia coli; Extract; Minimum inhibitory concentration; Minimum bactericidal concentration
The methanolic extract and conessine isolated from the stem bark of Holarrhena floribunda (Hf) were tested for their antibacterial activities on Bacillus: Bacillus cereus, Bacillus subtilis, Bacillus megaterium and Bacillus stearothermophilus using the disc diffusion method. Phytochemical analysis of the crude extract and fractions was also conducted. The inhibition parameters of the crude methanol extract and the total alkaloid fraction were determined using the macrodilution method. The results showed that the crude extract, the total alkaloid fraction and conessine exhibited a significant antibacterial effect against all the strains studied. The antibacterial effect of conessine is almost similar to that of chloramphenicol used as reference. The ratio of the minimal bactericidal concentration (MBC) over the minimal inhibitive concentration (MIC) indicates the bactericidal effect of the plant. These results support common use of stem bark of Hf and conessine isolated from Hf in the treatment of some infectious diseases.
Antibacterial activities; Holarrhena floribunda; Bacillus; conessine
To investigate the antibacterial and cytotoxic activity of fourteen different edible vegetables methanolic extract from Bangladesh.
The antibacterial activity was evaluated using disc diffusion assay method against 12 bacteria (both gram positive and gram negative). The plant extracts were also screened for cytotoxic activity using the brine shrimp lethality bioassay method and the lethal concentrations (LC50) were determined at 95% confidence intervals by analyzing the data on a computer loaded with “Finney Programme”.
All the vegetable extracts showed low to elevated levels of antibacterial activity against most of the tested strains (zone of inhibition=5-28 mm). The most active extract against all bacterial strains was from Xanthium indicum which showed remarkable antibacterial activity having the diameter of growth inhibition zone ranging from 12 to 28 mm followed by Alternanthera sessilis (zone of inhibition=6-21 mm). All extracts exhibited considerable general toxicity towards brine shrimps. The LC50 value of the tested extracts was within the range of 8.447 to 60.323 µg/mL with respect to the positive control (vincristine sulphate) which was 0.91 µg/mL. Among all studied extracts, Xanthium indicum displayed the highest cytotoxic effect with LC50 value of 8.447 µg/mL.
The results of the present investigation suggest that most of the studied plants are potentially good source of antibacterial and anticancer agents.
Bangladeshi vegetables; Antibacterial; Disc diffusion; Brine shrimp lethality
Background & objectives:
Several chemical compounds isolated from natural sources have antibacterial activity and some enhance the antibacterial activity of antibiotics reversing the natural resistance of bacteria to certain antibiotics. In this study, the hexane and methanol extract of Cordia verbenaceae were assessed for antibacterial activity alone and combinated with norfloxacin against the Staphylococcus aureus strain SA1199B.
The minimum inhibitory concentration (MIC) of extracts was assayed using microdilution assay and the modulatory activity was evaluated using plate diffusion assay.
The MIC observed varied between 256 to >1024 μg/ml. However, the antibiotic activity of norfloxacin was enhanced in the presence of subinhibitory concentrations of hexane extract of C. verbenaceae (HECV).
Interpretations & conclusions:
Our results indicate that Cordia verbenaceae DC. can be a source of plant derived products with antibiotic modifying activity.
Antibacterial activity; antibiotics; Cordia verbenaceae DC; hexane extract; modulation of resistance; Staphylococcus aureus
The current paper investigated the potential benefit of the traditional Mexican medicinal plant Laennecia confusa (Cronquist) G. L. Nesom (Asteraceae). Fractions from the hexane, chloroform, methanol, and aqueous extracts were analyzed for antibacterial, antifungal, anti-inflammatory, and antiparasitic activities. The antimicrobial activity of the extracts and fractions was assessed on bacterial and fungal strains, in addition to the protozoa Leishmania donovani, using a microdilution assay. The propensity of the plant's compounds to produce adverse effects on human health was also evaluated using propidium iodine to identify damage to human macrophages. The anti-inflammatory activity of the extracts and fractions was investigated by measuring the secretion of interleukin-6. Chemical analyses demonstrated the presence of flavonoids, cyanogenic and cardiotonic glycosides, saponins, sesquiterpene lactones, and triterpenes in the chloroform extract. A number of extracts and fractions show antibacterial activity. Of particular interest is antibacterial activity against Staphylococcus aureus and its relative methicillin-resistant strain, MRSA. Hexanic and chloroformic fractions also exhibit antifungal activity and two extracts and the fraction CE 2 antiparasitic activity against Leishmania donovani. All bioactive extracts and fractions assayed were also found to be cytotoxic to macrophages. In addition, the hexane and methane extracts show anti-inflammatory activity by suppressing the secretion of interleukine-6.
Records have shown that Combretum adenogonium Steud. Ex A. Rich (Combretaceae) is used in traditional medicine systems of several tribes in Tanzania. This study focused on the investigation of antibacterial activity, anti-HIV-1 protease activity, toxicity properties and classes of phytochemicals in extracts from C. adenogonium Steud. Ex A. Rich (Combretaceae) to evaluate potential of these extracts for development as herbal remedies.
Dried plant material were ground to fine powder and extracted using 80% aqueous ethanol to afford root, leaf and stem bark extracts. The extracts were assayed for anti-HIV-1 protease activities, antibacterial activities using microdilution methods and cytotoxicity using brine shrimps lethality assay. Screening for major phytochemical classes was carried out using standard chemical tests.
All extracts exhibited antibacterial activity to at least one of the test bacteria with MIC-values ranging from 0.31-5.0 mg/ml. Two extracts, namely, root and stem bark exhibited anti-HIV-1 PR activity with IC50 values of 24.7 and 26.5 μg/ml, respectively. Stem bark and leaf extracts showed mild toxicity with LC50 values of 65.768 μg/ml and 76.965 μg/ml, respectively, whereas roots were relatively non-toxic (LC50 = 110.042 μg/ml). Phytochemical screening of the extracts indicated presence of flavonoids, terpenoids, alkaloids, tannins, glycosides and saponins.
These results provide promising baseline information for the potential development of C. adenogonium extracts in treatment of bacterial and HIV/AIDS-related opportunistic infections.
Combretum adenogonium; Combretaceae; Anti-HIV-1 protease; Antibacterial; Cytotoxicity
This study was designed to examine the chemical composition and in vitro antimicrobial potential of methanolic extract of Psidium guajava Linn (Myrtaceae).
Materials and Methods:
The inhibitory effect of methanolic extract of P. guajava was tested against three bacterial and two fungal strains by using the paper disc diffusion method.
The methanolic extract exhibited antibacterial activity against E. coli with minimum inhibitory concentration, 0.78 μg/ml, minimum bactericidal concentration of 50 μg/ml, and appreciable antifungal activity with minimum inhibitory concentration of 12.5 μg/ml. Preliminary phytochemical analysis of methanolic extract revealed the presence of antimicrobial compounds such as flavonoids, steroids, and tannins, which may contribute for the antimicrobial action of P. guajava.
The extract was found to be bacteriostatic and fungistatic in action.
Antimicrobial activity; paper disc diffusion method; Psidium guajava
Antibacterial and phytochemical screening of methanolic, sequential extracts (hexane, dichloromethane, ethyl acetate and methanol) and alkaloid rich fractions of Tabernaemontana stapfiana Britten was carried out. The phytochemical screening showed the presence of alkaloids, flavonoids, coumarins, tannins and saponins that have been associated with antimicrobial activity. The stem and root bark methanolic extracts showed good activity against the bacterial strains used including the multiple drug resistant Staphylococcus aureus strain with minimum inhibitory concentrations ranging from 15.6 to 500 µg/ml and minimum bactericidal concentrations ranging from 31.25 to 500 µg/ml. The sequential extracts of the root and stem bark had high antimicrobial activity with minimum inhibitory concentrations (MICs) ranging between 3.9 and 250 µg/ml and minimum bactericidal concentrations (MBCs) ranging between 7.8 and 500 µg/ml against the tested microorganisms. The dichloromethane extract of the alkaloid rich fractions however exhibited reduced antibacterial activities as compared to methanol and sequential extracts but the dichloromethane:methanol (4:1) mixture showed high activity with MICs ranging between 15.6 and 250 µg/ml. These antibacterial efficacy studies suggest that Tabernaemontana stapfiana Britten could be a source of antibacterial agents.
Tabernaemontana stapfiana; Antibacterial; MICs; MBCs
In this study antibacterial, antifungal and cytotoxic effects of some new 2,3-disubstituted 4(3H)-quinazolinone derivatives have been evaluated. The in vitro antibacterial and antifungal tests of new synthesized compounds were performed using MABA method against six strains of bacteria (three Grampositive and three Gram-negative) and three strains of fungi. Also Minimum Bactericidal Concentration (MBC) and Minimum Fungicidal Concentration (MFC) tests were performed. All synthesized compounds indicated mild antibacterial effects especially against Gram-negative bacteria. The most sensitive bacteriumwas E. coli. All strains of tested fungi were sensitive to the synthesized compounds mostly at 32 μg/ml and there was no significant differences in the sensitivity of the tested compounds. MBC and MFC data indicated that tested compounds act as bactriostatic and fungistatic agents. Cytotoxic activity of the compounds was screened at 1, 10 and 100 μM concentrations against HeLa cells using the MTT colorimetric assay. While the synthesized compounds did not show significant cytotoxic activities, compounds 7a3 and 7a4 reduced cell viability to about 50% at 100 μM concentration. The present study revealed that most of the new synthesized compounds possess good antifungal effects and they could be considered as valuable candidates for further structural modification to design more potent antifungal agents.
4(3H)-Quinazolinone; Antibacterial; Antifungal; Cytotoxicity
The emergence of multi-drug resistant (MDR) phenotypes is a major public health problem today in the treatment of bacterial infections. The present study was designed to evaluate the antibacterial activities of the methanol extracts of eleven Cameroonian spices on a panel of twenty nine Gram negative bacteria including MDR strains.
The phytochemical analysis of the extracts was carried out by standard tests meanwhile the liquid micro-broth dilution was used for all antimicrobial assays.
Phytochemical analysis showed the presence of alkaloids, phenols and tannins in all plants extracts. The results of the antibacterial assays indicated that all tested extracts exert antibacterial activities, with the minimum inhibitory concentration (MIC) values varying from 32 to 1024 μg/ml. The extracts from Dichrostachys glomerata, Beilschmiedia cinnamomea, Aframomum citratum, Piper capense, Echinops giganteus, Fagara xanthoxyloïdes and Olax subscorpioïdea were the most active. In the presence of efflux pump inhibitor, PAßN, the activity of the extract from D. glomerata significantly increased on 69.2% of the tested MDR bacteria. At MIC/5, synergistic effects were noted with the extract of D. glomerata on 75% of the tested bacteria for chloramphenicol (CHL), tetracycline (TET) and norfloxacin (NOR). With B. cinnamomea synergy were observed on 62.5% of the studied MDR bacteria with CHL, cefepime (FEP), NOR and ciprofloxacin (CIP) and 75% with erythromycin (ERY).
The overall results provide information for the possible use of the studied extracts of the spices in the control of bacterial infections involving MDR phenotypes.
Physalis minima is an important medicinal plant of Indian System of Medicine. This plant is reported for its diuretic, laxative and antiinflammatory activities. However, the plant is not well scrutinized for its antimicrobial potential. The major chemical constituents reported from the plant are phenolics and alkaloids, which suggest that the plant may turn out to be a potent antiinfective agent. The aim of the study was to find out the antibacterial potential of mature berries of P. minima using streak plate, well diffusion, determination of minimum inhibitory concentration and bioautographic methods against a battery of Gram positive and Gram negative bacterial strains. Results of the study showed that methanol and chloroform extracts of P. minima exhibited potent inhibitory activity against all the bacterial strains tested. Minimum inhibitory concentration found out was 100 μg in both the extracts. Bioautography assay showed polar compounds present in the crude extract are responsible for the antimicrobial action.
Bioautography; minimum inhibitory concentration; Physalis minima; thin layer chromatography
In the present investigation, aqueous, ethanol and petroleum ether, ethanol (1:1) root extracts of Seidenfia rheedii were tested against 12 different human pathogenic bacteria for antibacterial activity. It was found that ethanolic extracts inhibited the growth of all the bacterial strains tested whereas moderate antibacterial activity was associated with petroleum ether, ethanol (1:1) root extracts. The aqueous extract did not show antibacterial activity. Thus the present investigation reveals that the selected plant extracts have potential of bactericidal effect on test bacteria.
Seidenfia rheedii; Antibacterial activity; Bactericidal; root extracts
The present study describes the phytochemical profile and antimicrobial activity of Sesuvium portulacastrum.
Materials and Methods:
Three extracts of S. portulacastrum obtained by extraction in aqueous, ethanolic and dichloromethane solvents, respectively, were compared for their antimicrobial activity and ethanolic extract further subjected to gas chromatography-mass spectrometry (GC-MS) analysis to find out the nature of the compounds responsible for the antimicrobial activity. The antibacterial activities were assessed by measuring the diameter of the inhibition zones, minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) values.
Compared to the aqueous and dichloromethane extract, the ethanolic extract showed better antimicrobial activity against Staphylococcus aureus and E. coli, indicating its potential application related to noscomial infections. GC-MS results revealed 22, 23-Dihydrostigmasterol, Benzoic acid, 3,4,5-trihydroxy-(Gallic acid), (2R,3R)-(-)-Epicatechin and Capsaicin in the ethanolic extract to be the molecules responsible for the antimicrobial activity of S. portulacastrum.
To the best of our knowledge, this is the first report on analysis of antimicrobial components from S. portulacastrum in United Arab Emirates (UAE), and our results confer the utility of this plant extract in developing a novel broad spectrum antimicrobial agent.
Antibacterial; gas chromatography-mass spectrometry; phytochemical; Sesuvium portulacastrum
This study was undertaken with an objective of testing the antibacterial and antifungal activities of Bauhinia purpurea leaves and identifying the bioactive compounds. The antimicrobial activity of leaf extract was determined in aqueous and organic extracts and the minimum inhibitory concentration (MIC) against six species of pathogenic and non-pathogenic microorganisms: Bacillus subtilis, Staphylococcus aureus, Salmonella typhi, Escherichia coli, Pseudomonas aeruginosa and Candida albicans using the disk diffusion method. The chemical constituents of organic plant extract were separated by thin layer chromatography and purified by column chromatography and further identified by gas chromatography–mass spectrometry (GC–MS) analysis. Significant inhibitory activity was observed with methanol extracts of plant against the test microorganisms while less antibacterial activity was observed in hexane, acetone and aqueous extracts. MIC of B. purpurea extract was ≤1,500 μg/ml against S. aureus and B. subtilis while this extract showed no inhibition against Gram-negative S. typhi, E. coli and P. aeruginosa or against fungus C. albicans. Eleven compounds were identified in B. purpurea leaf extract by GC–MS analysis. The composition of B. purpurea revealed the presence of lupeol, stigmasterol, lanosterol, ergosterol, beta-tocopherol, phytol, hexadeconic acids, hexadeconic acids methyl esters, octadecadienoic acids and octadecatrienoic acid. Stigmasterol and lupeol were the most abundant (34.48 and 15.63 %). Other phytosterols like lanosterol (4.15 %) and ergosterol (2.82 %) were also found to be present in this extract.
Antimicrobial activity; Medicinal plants; MIC; TLC; GC–MS
The essential oil from the leaves of Feronia limonia was extracted and the chemical constituents and antibacterial activity were studied. The GC and GC-MS analyses revealed that the leaf essential oil of F. limonia contained fourteen compounds representing about 98.4% of the total oil. The major chemical compounds identified were Eudesma-4 (14).11-dine (46.3%), carvacrol (29.6%) and 1,5-cyclodecandine (13.4%). The essential oil was screened for its antibacterial activity against different clinically isolated Gram positive and Gram negative bacterial strains by disc diffusion and minimum inhibitory concentration assay. The essential oil exhibited moderate antibacterial activity against all the tested bacterial strains with MIC values ranging from 125 to 500 μg/mL except Proteus mirabilis.
Antibacterial activity; Chemical constituents; Feronia limonia; Essential oil
Ceragenin CSA-13 is a synthetic mimic of cationic antibacterial peptides, with facial amphiphilic morphology reproduced using a cholic acid scaffold. Previous data have shown that this molecule displays broad-spectrum antibacterial activity, which decreases in the presence of blood plasma. However, at higher concentrations, CSA-13 can cause lysis of erythrocytes. This study was designed to assess in vitro antibacterial and haemolytic activity of CSA-13 in the presence of pluronic F-127.
Methods and Results
CSA-13 bactericidal activity against clinical strains of bacteria associated with topical infections and in an experimental setting relevant to their pathophysiological environment, such as various epithelial tissue fluids and the airway sputum of patients suffering from cystic fibrosis (CF), was evaluated using minimum inhibitory and minimum bactericidal concentration (MIC /MBC) measurements and bacterial killing assays. We found that in the presence of pluronic F-127, CSA-13 antibacterial activity was only slightly decreased, but CSA-13 haemolytic activity was significantly inhibited. CSA-13 exhibits bacterial killing activity against clinical isolates of Staphylococcus aureus, including methicillin-resistant strains, Pseudomonas aeruginosa present in CF sputa, and biofilms formed by different Gram (+) and Gram (−) bacteria. CSA-13 bactericidal action is partially compromised in the presence of plasma, but is maintained in ascites, cerebrospinal fluid, saliva, and bronchoalveolar lavage fluid. The synergistic action of CSA-13, determined by the use of a standard checkerboard assay, reveals an increase in CSA-13 antibacterial activity in the presence of host defence molecules such as the cathelicidin LL-37 peptide, lysozyme, lactoferrin and secretory phospholipase A (sPLA).
These results suggest that CSA-13 may be useful to prevent and treat topical infection.
Significance and Impact of the Study
Combined application of CSA-13 with pluronic F-127 may be beneficial by reducing CSA-13 toxicity.
antibacterial agents; microbiological assay; pluronic F-127