The antibacterial activities of honey

Honey is a powerful antimicrobial agent with a wide range of effects. Various components contribute to the antibacterial efficacy of honey: the sugar content; polyphenol compounds; hydrogen peroxide; 1,2-dicarbonyl compounds; and bee defensin-1. All of these elements are present at different concentrations depending on the source of nectar, bee type, and storage. These components work synergistically, allowing honey to be potent against a variety of microorganisms including multidrug resistant bacteria and modulate their resistance to antimicrobial agents. The effectiveness and potency of honey against microorganisms depends on the type of honey produced, which is contingent on its botanical origin, the health of the bee, its origin, and processing method. The application of antibiotics with honey yielded better antimicrobial potential and synergistic effects were noted against biofilms. In medicine, honey has been used in the treatment of surface wounds, burns, and inflammation, and has a synergistic effect when applied with antibiotics. Tissue repair is enhanced by the low pH of honey (3.5–4): causing a reduction in protease activity on the wound site, elevating oxygen release from hemoglobin and stimulating fibroblast and macrophage activity. Furthermore, H₂O₂ has antiseptic effects, and it disinfects the wound site and stimulates production of vascular endothelial growth factor. The use of honey will clean wounds or burn areas from free radicals and reduces scarring and contractures. The anti-inflammatory and antibacterial potential of honey will keep the injured area moist and as such prevents it from deterioration and fibrosis. Honey can promote fast healing and reduce scarring and is very convenient for plastic surgery. Skin maceration is protected by honey due to its high osmolarity and because it keeps the injury moist. In non-infected areas, honey still reduced pain and inflammation. In general, the use of honey in medical settings has reduced economic loss and provided proven economic benefits by lowering direct costs in comparison to conventional treatments and by using less antibiotics, faster healing and less hospitalization stay. This review is intended to provide an overview of the antibacterial activities of honey and its applications.     

Floral markers and biological activity of Saudi honey

The objectives of this research were to identify certain chemical compounds that may be used as fingerprints of Saudi honey and to evaluate their antioxidant and antibacterial activities. Eleven Saudi ‘monofloral’ honey samples were analyzed and evaluated. Non-phenolic compounds, such as 2,3-dihydro-3,5-dihydroxy-6-methyl-4H-pyran-4-one, methyl 3-hydroxyhexanaote and 5-hydroxymethyl-2-furancarboxaldehyde were present in different types of tested honey samples. Glyceraldehyde was only detected in five of the honey samples tested. The most promising result was the detection of an alkaloid (by using GC–MS) in only two types of Saudi honey samples. This alkaloid may be of great importance and has the potential to be used as a fingerprint marker for the botanical sources of the various honey samples tested. This alkaloid was present in Toran and Saha. The detected compound is 2-amino-4-hydroxypteridine-6-carboxylic acid, which may originate from the degradation of folic acid as identified by previous studies. These findings can be used as a gateway to obtain a fingerprint for these two types of honey samples and can potentially be used to track any impurities in honey sold on the market. All of the tested honey samples showed antioxidant and antibacterial activities. The highly effective activity was in Toran honey against Staphylococcus aureus and Methicillin resistant Staphylococcus aureus (MRSA). Shafalah honey was effective against MRSA and Acinetobacter baumannii which showed bactericidal effects at concentrations 70–100%. This study also examined the antioxidant activity of honey samples using the DPPH assay. DPPH values of tested honey samples varied between 53.93?±?0.21%, as the highest value and 5.89?±?0.125%, as the lowest value. Significant correlations between the antibacterial and the antioxidant activities of the tested honey samples were noticed. The corresponding total phenolic contents (TPC) values supported the fact that phenolic compounds enhanced the antibacterial activity. The study revealed that some of the locally produced honey samples, specifically Zaitoon, Shaflah, Saha, Rabea Aja and Bareq contained the monosaccharides called glyceraldehydes which was the precursor to produce methylglyoxal (MGO) compound, which has antibacterial effects as documented in several previous studies. There was no clear relationship between these activities and the sum total of phenolic compounds present in Saudi honey.     

A comparison of the sensitivity of wound-infecting species of bacteria to the antibacterial activity of manuka honey and other honey.

Both honey and sugar are used with good effect as dressings for wounds and ulcers. The good control of infection is attributed to the high osmolarity, but honey can have additional antibacterial activity because of its content of hydrogen peroxide and unidentified substances from certain floral sources. Manuka honey is known to have a high level of the latter. Seven major wound-infecting species of bacteria were studied to compare their sensitivity to the non-peroxide antibacterial activity of manuka honey and to a honey in which the antibacterial activity was primarily due to hydrogen peroxide. Honeys with activity in the middle of the normal range were used. A comparison of the median response of the various species of bacteria showed no significant difference between the two types of activity overall, but marked differences between the two types of activity in the rank order of sensitivity of the seven bacterial species. The non-peroxide antibacterial activity of manuka honey at a honey concentration of 1.8% (v/v) completely inhibited the growth of Staphylococcus aureus during incubation for 8 h. The growth of all seven species was completely inhibited by both types of honey at concentrations below 11% (v/v).     

A comparison of the sensitivity of wound-infecting species of bacteria to the antibacterial activity of manuka honey and other honey

Both honey and sugar are used with good effect as dressings for wounds and ulcers. The good control of infection is attributed to the high osmolarity, but honey can have additional antibacterial activity because of its content of hydrogen peroxide and unidentified substances from certain floral sources. Manuka honey is known to have a high level of the latter.
Seven major wound-infecting species of bacteria were studied to compare their sensitivity to the non-peroxide antibacterial activity of manuka honey and to a honey in which the antibacterial activity was primarily due to hydrogen peroxide. Honeys with activity in the middle of the normal range were used. A comparison of the median response of the various species of bacteria showed no significant difference between the two types of activity overall, but marked differences between the two types of activity in the rank order of sensitivity of the seven bacterial species. The non-peroxide antibacterial activity of manuka honey at a honey concentration of 1.8% (v/v) completely inhibited the growth of Staphylococcus aureus during incubation for 8 h. The growth of all seven species was completely inhibited by both types of honey at concentrations below 11% (v/v).     

Antibacterial activity of honey and propolis from Apis mellifera and Tetragonisca angustula against Staphylococcus aureus

AIMS: The antibacterial activity against Staphylococcus aureus of honey and propolis produced by Apis mellifera and Tetragonisca angustula was evaluated. Secondary aims included the study of the chemical composition of propolis and honey samples and its relationship with antibacterial activity against S. aureus. METHODS AND RESULTS: The antibacterial activity of honey and propolis was determined by the method of macrodilution. The minimum inhibitory concentration (MICs) of A. mellifera honey ranged from 126.23 to 185.70 mg ml(-1) and of T. angustula from 142.87 to 214.33 mg ml(-1). For propolis, the MIC ranged from 0.36 to 3.65 mg ml(-1) (A. mellifera) and from 0.44 to 2.01 mg ml(-1) (T. angustula). Honey and propolis were evaluated by high-performance liquid chromatography. Some typical compounds of Brazilian propolis were also identified in honey samples. Principal component analysis revealed that the chemical composition of honey and propolis samples was distinct based on the geographical location of the samples. CONCLUSIONS: Propolis samples had higher antibacterial activity against S. aureus when compared with honey. However, both propolis and honey samples had antibacterial against S. aureus. SIGNIFICANCE AND IMPACT OF THE STUDY: These antimicrobial properties would warrant further studies on the clinical applications of propolis and honey against S. aureus.     

Antibacterial activity of honey from stingless honeybees (Hymenoptera; Apidae; Meliponinae).

The aim of the study was to examine antibacterial activity of the honey of stingless honeybees (Meliponinae). An agar well diffusion assay demonstrated that many honey samples of stingless honeybees inhibited the growth of test strains of Staphylococcus aureus, Enterococcus faecalis, Escherichia coli and Pseudomonas aeruginosa; moreover, they exhibited non-peroxide antibacterial activity against those strains. This is the first time that non-peroxide antimicrobial activity of honey from a number of species of stingless honeybees has been demonstrated. These antibacterial activities appear to be powerful, even when compared to those of"manuka honey" from Apinae honeybees.     

Electrospinning of honey and propolis for wound care

Phytochemicals and naturally derived compounds, such as plant extracts and bee products, are regarded as complementary and alternative medicines for the treatment of skin wounds, due to their antibacterial, anti-inflammatory, and antioxidant properties. In recent years, it has been shown that dressings impregnated with honey (particularly Manuka honey) are effective for the topical treatment of wounds and burns, and some of them are currently used in clinics. This has stimulated the development of more advanced dressings based on polymeric nanofibres that can release honey and other bee products (like propolis) to promote wound healing. In this review, the current literature on the electrospinning of honey and propolis is analyzed and the effectiveness of the resulting dressings to inhibit bacterial growth and stimulate cellular proliferation and tissue repair is discussed.     

In vitro effect of some Indian honeys on Staphylococcus aureus from wounds

Staphylococcus aureus is the most frequently isolated pathogen from wounds with multiple resistances to antibiotics. Honey has been demonstrated and reported to be effective antibacterial agent on Gram positive and Gram negative organisms. Hence, the present study was conducted to evaluate the in vitro antibacterial effect of Indian honeys on Staphylococcus aureus obtained from wounds. A total of 123 Staphylococcus aureus isolates along with ATCC 25923 were categorized as sensitive, multi drug resistant (MDR) and non-MDR strains. Out of total nine Indian honeys (three each of unifloral, multifloral and branded marketed honey) used, three unifloral and three multifloral honey samples showed antibacterial activity against all the organisms tested by Agar diffusion method but not the branded marketed honeys. The MIC values of all honey samples for all studied Staphylococcus aureus isolates ranged between 5-15% (v/v). Unifloral honey samples showed higher antibacterial activity than multifloral honey. The single sample of Jambhul honey showed the highest activity. Thus, Indian honeys were found to be effective for their antimicrobial activity on sensitive, non-MDR, MDR and ATCC strains of S. aureus.     

Synthesis and antibacterial evaluation of a novel tricyclic oxaborole-fused fluoroquinolone

We have designed and synthesized a novel class of compounds based on fluoroquinolone antibacterial prototype. The design concept involved the replacement of the 3-carboxylic acid in ciprofloxacin with an oxaborole-fused ring as an acid-mimicking group. The synthetic method employed in this work provides a good example of incorporating boron atom in complex molecules with multiple functional groups. The antibacterial activity of the newly synthesized compounds has been evaluated.     

Exometabolome analysis identifies pyruvate dehydrogenase as a target for the antibiotic triphenylbismuthdichloride in multiresistant bacterial pathogens

The desperate need for new therapeutics against notoriously antibiotic-resistant bacteria has led to a quest for novel antibacterial target structures and compounds. Moreover, defining targets and modes of action of new antimicrobial compounds remains a major challenge with standard technologies. Here we characterize the antibacterial properties of triphenylbismuthdichloride (TPBC), which has recently been successfully used against device-associated infections. We demonstrate that TPBC has potent antimicrobial activity against many bacterial pathogens. Using an exometabolome profiling approach, a unique TPBC-mediated change in the metabolites of Staphylococcus aureus was identified, indicating that TPBC blocks bacterial pyruvate catabolism. Enzymatic studies showed that TPBC is a highly efficient, uncompetitive inhibitor of the bacterial pyruvate dehydrogenase complex. Our study demonstrates that metabolomics approaches can offer new avenues for studying the modes of action of antimicrobial compounds, and it indicates that inhibition of the bacterial pyruvate dehydrogenase complex may represent a promising strategy for combating multidrug-resistant bacteria.     

Antioxidant and antibacterial capacity of stingless bee honey from Borneo (Sarawak)

Stingless honey bees form a large group of bees that lack of a sting and are found among Meliponinae species indigenous to various tropical and subtropical regions. They are able to produce “stingless bee honey” that contains divergent categories of phenolic and flavonoid compounds and have been associated with antioxidant and antibacterial activity. This study examines the physicochemical properties, antioxidant-activity and anti-microbial activity of stingless bee honey from Malaysia that was produced by Geniotrigona thoracica, Heterotrigona itama and Heterotrigona erythrogastra. The results show that G. thoracica honey has the highest concentration of the total phenolic context (99.04?±?5.14?mg/ml) and the greatest reducing power (19.05?±?0.79%), while flavonoids (17.67?±?0.75?mg/ml), reducing power (18.10?±?0.35%), DPPH (47.40?±?3.18%) and FRAP (50.66?±?5.77?mM of Fe²⁺/100?g) of H. itama honey is significantly higher than those of the other honeys. In addition, G. thoracica honey has the highest antibacterial activity against Staphylococcus xylosus (2.10?±?0.10?cm), which is Gram-positive bacterium, and against Pseudomonas aeruginosa (1.60?±?0.10?cm) and Vibrio parahaemolyticus (2.03?±?0.06?cm), which are Gram-negative bacteria. These results suggest that stingless bee honeys possess useful amounts of phenolic and flavonoid compounds that are able to act as natural anti-oxidants and also have significant anti-microbial activity.     

Antibacterial Compounds of Canadian Honeys Target Bacterial Cell Wall Inducing Phenotype Changes,Growth Inhibition and Cell Lysis That Resemble Action of β-Lactam Antibiotics

Honeys show a desirable broad spectrum activity against Gram-positive and negative bacteria making antibacterial activity an intrinsic property of honey and a desirable source for new drug development. The cellular targets and underlying mechanism of action of honey antibacterial compounds remain largely unknown. To facilitate the target discovery, we employed a method of phenotypic profiling by directly comparing morphological changes in Escherichia coli induced by honeys to that of ampicillin, the cell wall-active β-lactam of known mechanism of action. Firstly, we demonstrated the purity of tested honeys from potential β-lactam contaminations using quantitative LC-ESI-MS. Exposure of log-phase E. coli to honey or ampicillin resulted in time- and concentration-dependent changes in bacterial cell shape with the appearance of filamentous phenotypes at sub-inhibitory concentrations and spheroplasts at the MBC. Cell wall destruction by both agents, clearly visible on microscopic micrographs, was accompanied by increased permeability of the lipopolysaccharide outer membrane as indicated by fluorescence-activated cell sorting (FACS). More than 90% E. coli exposed to honey or ampicillin became permeable to propidium iodide. Consistently with the FACS results, both honey-treated and ampicillin-treated E. coli cells released lipopolysaccharide endotoxins at comparable levels, which were significantly higher than controls (p<0.0001). E. coli cells transformed with the ampicillin-resistance gene (β–lactamase) remained sensitive to honey, displayed the same level of cytotoxicity, cell shape changes and endotoxin release as ampicillin-sensitive cells. As expected, β–lactamase protected the host cell from antibacterial action of ampicillin. Thus, both honey and ampicillin induced similar structural changes to the cell wall and LPS and that this ability underlies antibacterial activities of both agents. Since the cell wall is critical for cell growth and survival, honey active compounds would be highly applicable for therapeutic purposes while differences in the mode of action between honey and ampicillin may provide clinical advantage in eradicating β-lactam-resistant pathogens.     

Potential effects of Saudi Shaoka (Fagonia bruguieri) honey against multi-drug-resistant bacteria and cancer cells in comparison to Manuka honey

The global spread of antimicrobial-resistant infectious diseases and cancer are the most widespread public health issue and has led to high mortality rates. This study aims to evaluate and verify the antibacterial and antitumor activities of Shaoka and Manuka honey against pathogenic bacteria, human hepatocarcinoma (HepG2) and breast cancer (MCF-7) cell lines. Shaoka hone was analyzed using HPLC, UV–vis, and GC/MC, while antibacterial activity was measured by agar diffusion, broth microdilution methods, and Transmission Electron Microscopy (TEM). Antitumor activity was investigated morphologically and by MTT assay. According to the presented data of HPLC analysis, Shaoka honey was generally richer in polyphenolic components, the antibacterial activity showed that Shaoka honey is equivalent or relatively more active than Manuka honey against a broad spectrum of multi-drug-resistant bacteria. It inhibited the growth of ESBL Escherichia coli in the absence or presence of catalase enzyme with a concentration approximately 8.5%–7.3% equivalent to phenol, which supported the highest level of non-peroxide-dependent activity. The minimum bactericidal concentrations (MBCs) ranged between 5.0% and 15.0% honey (w/v). TEM observation revealed distorted cell morphology, cytoplasmic shrinkage, and cell wall destruction of treated bacteria. The selected honey exerted cytotoxicity on both cancer cell lines, inhibiting cell proliferation rate and viability percent in HepG2 and MCF-7 cancer cells, by different degrees depending on the honey quality, Shaoka honey competed Manuka inhibitory effects against both cancer cells. The obtained data confirmed the potential for use of Saudi Shaoka honey as a remedy, this well introduces a new honey template as medical-grade honey for treating infectious disease and cancer.     

Use of a spectrophotometric bioassay for determination of microbial sensitivity to manuka honey

The antimicrobial activity of manuka honey has been well documented (Molan, 1992a,b,c, 1997) [Molan, P.C., 1992. The antibacterial activity of honey. 1: the nature of the antibacterial activity. Bee World 73 (1) 5-28; Molan, P.C., 1992. The antibacterial activity of honey. 2: variation in the potency of the antibacterial activity. Bee World 73 (2) 59-76; Molan, P.C., 1992. Medicinal uses for honey. Beekeepers Quarterly 26; Molan, P.C., 1997. Finding New Zealand honeys with outstanding antibacterial and antifungal activity. New Zealand Beekeeper 4 (10) 20-26]. The current bioassays for determining this antimicrobial effect employ a well diffusion (Ahn and Stiles, 1990) [Ahn, C., Stiles, M.E., 1990. Antibacterial activity of lactic acid bacteria isolated from vacuum-packed meats. Journal of Applied Bacteriology 69, 302-310], (Weston et al., 1999) [Weston, R.J., Mitchell, K.R., Allen, K.L., 1999. Antibacterial phenolic components of New Zealand manuka honey. J. Food Chem. 64, 295-301] or disc diffusion (Taormina et al., 2001) [Taormina, Peter J., Niemira, Brendan A., Beuchat, Larry R., 2001. Inhibitory activity of honey against food borne pathogens as influenced by the presence of hydrogen peroxide and level of antioxidant power. Int. J. Food Microbiol. 69, 217-225] assay using zones of inhibition as indicators of bacterial susceptibility. The development of a 24-h spectrophotometric assay employing 96-well microtiter plates, that is more sensitive and more amenable to statistical analysis than the assays currently employed, was undertaken. This simple and rapid assay permits extensive kinetic studies even in the presence of low honey concentrations, and is capable of detecting inhibitory levels below those recorded for well or disc diffusion assays. In this paper, we compare the assay to both well and disc diffusion assays. The results we obtained for the spectrophotometric method MIC values show that this method has greater sensitivity than the standard well and disc diffusion assays. In addition, inter- and intra-assay variance for this method was investigated, demonstrating the methods reproducibility and repeatability.     

蜂蜜的抗菌机理及其抗菌效果的影响因素

利用蜂蜜的抗菌特性治疗各种疾病或创伤是蜂蜜开发中一个比较热门的方向。本文对蜂蜜可能的抗菌机理以及蜂蜜中的抗菌组分作了阐述,对影响蜂蜜抗菌效果的因素以及蜂蜜抗菌特性的医学应用进行了探讨。     

Two major medicinal honeys have different mechanisms of bactericidal activity

Honey is increasingly valued for its antibacterial activity, but knowledge regarding the mechanism of action is still incomplete. We assessed the bactericidal activity and mechanism of action of Revamil® source (RS) honey and manuka honey, the sources of two major medical-grade honeys. RS honey killed Bacillus subtilis, Escherichia coli and Pseudomonas aeruginosa within 2 hours, whereas manuka honey had such rapid activity only against B. subtilis. After 24 hours of incubation, both honeys killed all tested bacteria, including methicillin-resistant Staphylococcus aureus, but manuka honey retained activity up to higher dilutions than RS honey. Bee defensin-1 and H₂O₂ were the major factors involved in rapid bactericidal activity of RS honey. These factors were absent in manuka honey, but this honey contained 44-fold higher concentrations of methylglyoxal than RS honey. Methylglyoxal was a major bactericidal factor in manuka honey, but after neutralization of this compound manuka honey retained bactericidal activity due to several unknown factors. RS and manuka honey have highly distinct compositions of bactericidal factors, resulting in large differences in bactericidal activity.     

Antibacterial potential of some Saudi honeys from Asir region against selected pathogenic bacteria

Honey is a nutrient rich natural product and has been utilized as traditional and complementary medicine since ancient times. In this study, antibacterial activity of Sider (Ziziphus spina-christi), Dharm (Lavandula dentata), and Majra (Hypoestes forskaolii) honey samples collected from Asir region of Saudi Arabia was in vitro evaluated at 80% and 50% w/v concentrations against five pathogenic bacteria i.e. Escherichia coli, Proteus mirabilis, Staphylococcus aureus, Shigella flexneri, and Staphylococcus epidermidis. Well diffusion assays to measure the average zone of inhibition (ZOI) and minimum inhibitory concentration (MIC) values were employed in the experiments. All the tested honey samples showed antibacterial activity in a dose-dependent manner. Sider and Dharm exhibited a good antibacterial activity at high concentrations while, Majra honey of Apis mellifera jemenitica and of Apis florea showed comparatively low antibacterial activity. The average MIC values of Sider, Dhram from Rijal Alma, Dharm from Al-Souda, Majra (A.m. jemenitica), and Majra (A. florea) honey against all tested bacteria were 22%, 16%, 18%, 32%, and 28% (v/v) respectively. Dharm and Sider honeys showed better antibacterial activity than Majra honey. Saudi honey can be considered as a promising future antimicrobial agent and should be further investigated as an alternative candidate in the management of resistant bacterial pathogens.     

Activities of different types of Thai honey on pathogenic bacteria causing skin diseases,tyrosinase enzyme and generating free radicals

Background

Honey is a natural product obtained from the nectar that is collected from flowers by bees. It has several properties, including those of being food and supplementary diet, and it can be used in cosmetic products. Honey imparts pharmaceutical properties since it has antibacterial and antioxidant activities. The antibacterial and antioxidant activities of Thai honey were investigated in this study.

Results

The honey from longan flower (source No. 1) gave the highest activity on MRSA when compared to the other types of honey, with a minimum inhibitory concentration of 12.5% (v/v) and minimum bactericidal concentration of 25% (v/v).Moreover, it was found that MRSA isolate 49 and S. aureus were completely inhibited by the 50% (v/v) longan honey (source No. 1) at 8 and 20 hours of treatment, respectively. Furthermore, it was observed that the honey from coffee pollen (source No. 4) showed the highest phenolic and flavonoid compounds by 734.76 mg gallic/kg of honey and 178.31 mg quercetin/kg of honey, respectively. The antioxidant activity of the honey obtained from coffee pollen was also found to be the highest, when investigated using FRAP and DPPH assay, with 1781.77 mg FeSO₄•7H₂O/kg of honey and 86.20 mg gallic/kg of honey, respectively. Additionally, inhibition of tyrosinase enzyme was found that honey from coffee flower showed highest inhibition by 63.46%.

Conclusions

Honey demonstrates tremendous potential as a useful source that provides anti-free radicals, anti-tyrosinase and anti-bacterial activity against pathogenic bacteria causing skin diseases.     

The Effect of New Zealand Kanuka,Manuka and Clover Honeys on Bacterial Growth Dynamics and Cellular Morphology Varies According to the Species

Treatment of chronic wounds is becoming increasingly difficult due to antibiotic resistance. Complex natural products with antimicrobial activity, such as honey, are now under the spotlight as alternative treatments to antibiotics. Several studies have shown honey to have broad-spectrum antibacterial activity at concentrations present in honey dressings, and resistance to honey has not been attainable in the laboratory. However not all honeys are the same and few studies have used honey that is well defined both in geographic and chemical terms. Here we have used a range of concentrations of clover honey and a suite of manuka and kanuka honeys from known geographical locations, and for which the floral source and concentration of methylglyoxal and hydrogen peroxide potential were defined, to determine their effect on growth and cellular morphology of four bacteria: Bacillus subtilis, Escherichia coli, Staphylococcus aureus and Pseudomonas aeruginosa. While the general trend in effectiveness of growth inhibition was manuka>manuka-kanuka blend>kanuka>clover, the honeys had varying and diverse effects on the growth and cellular morphology of each bacterium, and each organism had a unique response profile to these honeys. P. aeruginosa showed a markedly different pattern of growth inhibition to the other three organisms when treated with sub-inhibitory concentrations of honey, being equally sensitive to all honeys, including clover, and the least sensitive to honey overall. While hydrogen peroxide potential contributed to the antibacterial activity of the manuka and kanuka honeys, it was never essential for complete growth inhibition. Cell morphology analysis also showed a varied and diverse set of responses to the honeys that included cell length changes, cell lysis, and alterations to DNA appearance. These changes are likely to reflect the different regulatory circuits of the organisms that are activated by the stress of honey treatment.     

Synthesis and antibacterial activity of 5-substituted oxazolidinones

A series of 5-substituted oxazolidinones with varying substitution at the 5-position of the oxazolidinone ring were synthesized and their in vitro antibacterial activity was evaluated. The compounds demonstrated potent to weak antibacterial activity. A novel compound (PH-027) demonstrated potent antibacterial activity, which is comparable to or better than those of linezolid and vancomycin against antibiotic-susceptible standard and clinically isolated resistant strains of gram-positive bacteria. Although the presence of the C-5-acetamidomethyl functionality at the C-5 position of the oxazolidinones has been widely claimed and reported as a structural requirement for optimal antimicrobial activity in the oxazolidinone class of compounds, our results from this work identified the C-5 triazole substitution as a new structural alternative for potent antibacterial activity in the oxazolidinone class.