A review on recent research results (2008-2010) on essential oils as antimicrobials and antifungals. A review

The Application of Metabolomics to Probiotic and Prebiotic Interventions in Human Clinical Studies

There is an ever-increasing appreciation for our gut microbiota that plays a crucial role in the maintenance of health, as well as the development of disease. Probiotics are live bacteria that are consumed to increase the population of beneficial bacteria and prebiotics are dietary substrates intended to promote the propagation of beneficial bacteria. In order to optimize the use of probiotics and prebiotics, a more complete biochemical understanding of the impact that these treatments have on the community and functioning of the gut microbiota is required. Nucleic acid sequencing methods can provide highly detailed information on the composition of the microbial communities but provide less information on the actual function. As bacteria impart much of their influence on the host through the production of metabolites, there is much to be learned by the application of metabolomics. The focus of this review is on the use of metabolomics in the study of probiotic and prebiotic treatments in the context of human clinical trials. Assessment of the current state of this research will help guide the design of future studies to further elucidate the biochemical mechanism by which probiotics and prebiotics function and pave the way toward more personalized applications.

Microbial indices of industrial and traditional medicinal herbs in Ahvaz, Iran

Introduction. Medicinal herbs are susceptible to microbial contamination which can have profound effects on the consumer’s health. Our study aimed to evaluate microbial contamination of common medicinal herbs in Ahvaz. Study objects and methods. We collected 80 samples of traditional and industrial medicinal plants from the supply market, namely valeriana, fennel, licorice, and shirazi thyme. The reference method was used to determine microbial indices such as the total count of microorganisms, yeast and mold, Bacillus cereus, coliforms, and Escherichia coli. Results and discussion. We found that the total microbial count, yeast and mold, B. cereus, and coliform contamination accounted for 45, 77, 55, and 55% of the total samples, respectively, exceeding the allowed limits. There was a significant difference between the industrial and traditional samples in fungal and coliform contamination, with the traditional samples being more highly contaminated. However, no significant difference was observed between them in total count and B. cereus contamination. E. coli contamination was detected in 31.2% of the samples, mostly in traditional. Total microbial count and yeast and mold contamination were highest among valeriana plants. Fennel showed the highest B. cereus and coliform contamination. The lowest contamination was observed in licorice. Conclusion. The results showed that a considerable percentage of the medicinal herbs under study were contaminated at levels exceeding the standard limits. Plants could be contaminated during harvesting, processing or storage. Finally, different species of plants have different antimicrobial activities that affect their microbial contamination.

Advances in the control of phytopathogenic fungi that infect crops through their root system

Productivity and economic sustainability of many herbaceous and woody crops are seriously threatened by numerous phytopathogenic fungi. While symptoms associated with phytopathogenic fungal infections of aerial parts (leaves, stems and fruits) are easily observable and therefore recognizable, allowing rapid or preventive action to control this type of infection, the effects produced by soil-borne fungi that infect plants through their root system are more difficult to detect. The fact that these fungi initiate infection and damage underground implies that the first symptoms are not as easily noticeable, and therefore both crop yield and plant survival are frequently severely compromised by the time the infection is found. In this paper we will review and discuss recent insights into plant-microbiota interactions in the root system crucial to understanding the beginning of the infectious process. We will also review different methods for diminishing and controlling the infection rate by phytopathogenic fungi penetrating through the root system including both the traditional use of biocontrol agents such as antifungal compounds as well as some new strategies that could be used because of their effective application, such as nanoparticles, virus-based nanopesticides, or inoculation of plant material with selected endophytes. We will also review the possibility of modeling and influencing the composition of the microbial population in the rhizosphere environment as a strategy for nudging the plant-microbiome interactions toward enhanced beneficial outcomes for the plant, such as controlling the infectious process.

Synergistic Effects of Essential Oils of Ammoides verticillata and Satureja candidissima Against Many Pathogenic Microorganisms

Background:

Antibiotic resistance is today one of the most serious threats to global health, food security and development. Due to the growing number of infections, treatment becomes more difficult, if not impossible, because of the loss of antibiotic efficacy.

Objective:

In the present investigation, the chemical composition of essential oils of Ammoides verticillata and Satureja candidissima and their synergistic effects on antimicrobial activities were investigated.

Methods:

The chemical composition of the essential oil was analyzed by Gas Chromatography (GC) and Gas Chromatography-Mass Spectroscopy (GC/MS). The antimicrobial activity of the essential oils was investigated using dilution-agar method against nine bacterial strains three Gram-negative Escherichia coli (ATCC 25922), Pseudomonas aeruginosa (ATCC 27853) and Salmonella typhi (ATCC 14028), and six Gram-positive: Staphylococcus aureus (ATCC 43300,) Clostridium sporogenes (ATCC 19404), Bacillus subtilis (ATCC 6633), Enterococcus faecalis (ATCC 7314), Lactobacillus rhamnosus (ATCC 53103) and Bacillus cereus (ATCC 14579).

Results:

The essential oil of A. verticillata was characterized principally by carvacrol (44,3%), Limonene (19,3%) and p-cymene (19,2%). The constituents identified of S. candidissima essential oil were principally oxygenated monoterpenes represented by pulegone (70,4%). The essential oil of A. verticillata had a good antimicrobial activity against four bacterial strains (Escherichia coli, Salmonella typhi, Lactobacillus rhamnosus and Bacillus cereus) with MIC and MBC values between 0.2-0.4 µl/ml and 0.2-6.2 µl/ml, respectively. While, S. candidissima essential oil had moderate antimicrobial activities against all strains with MIC and MBC values between 1.5-6.2 µl/ml and 6.2-12.5 µl/ml, respectively. The results of antimicrobial activity of essential oils blend presented higher antimicrobial activity against all tested bacteria with MIC and MBC values between 0.3-1.5 µl/ml and 0.4-6.2 µl/ml, respectively.

Conclusion:

The essential oils blend presented high antimicrobial activity compared to virgin oils. This activity can be due to the association of active compounds such as carvacrol and pulegone. These findings provide a new source of drugs that may help in therapy to lead to the development of a new treatment based on a combination of these essential oils against gram-negative and gram-positive bacteria that continue to pose a threat to public health.

The In Vitro Activity of Essential Oils against Helicobacter Pylori Growth and Urease Activity

The anti-H. pylori properties of 26 different commercial essential oils were examined in vitro by MIC (minimal inhibitory concentration) determination for the reference strain H. pylori ATCC 43504. We selected 9 essential oils with different anti-Helicobacter activities and established their phytochemical composition and urease inhibition activities. Phytochemical analysis of the selected essential oils by GC-MS method and antioxidant activity were performed. The phenol red method was used to screen the effect of essential oils on urease activity expressed as IC₅₀ (the half of maximal inhibitory concentration). The most active essential oils, with MIC = 15.6 mg/L, were thyme, lemongrass, cedarwood and lemon balm oils; MIC = 31.3 mg/L—oregano oil; MIC = 62.5 mg/L—tea tree oil; MIC = 125 mg/L—pine needle, lemon and silver fir oils with bactericidal effect. Urease activity was inhibited by these oils with IC₅₀ ranged from 5.3 to > 1049.9 mg/L. The most active was cedarwood oil (IC₅₀ = 5.3 mg/L), inhibiting urease at sub-MIC concentrations (MIC = 15.6 mg/L). The statistical principal component analysis allowed for the division of the oils into three phytochemical groups differing in their anti-H. pylori activity. To summarize, the activity in vitro of the five essential oils silver fir, pine needle, tea tree, lemongrass, and cedarwood oils against H. pylori was found in this paper for the first time. The most active against clinical strains of H. pylori were cedar wood and oregano oils. Moreover, cedarwood oil inhibited the urease activity at subinhibitory concentrations. This essential oil can be regarded as a useful component of the plant preparations supporting the eradication H. pylori therapy.

Co-Networks Poly(hydroxyalkanoates)-Terpenes to Enhance Antibacterial Properties

Biocompatible and biodegradable bacterial polyesters, poly(hydroxyalkanoates) (PHAs), were combined with linalool, a well-known monoterpene, extracted from spice plants to design novel antibacterial materials. Their chemical association by a photo-induced thiol-ene reaction provided materials having both high mechanical resistance and flexibility. The influence of the nature of the crosslinking agent and the weight ratio of linalool on the thermo-mechanical performances were carefully evaluated. The elongation at break increases from 7% for the native PHA to 40% for PHA-linalool co-networks using a tetrafunctional cross-linking agent. The materials highlighted tremendous anti-adherence properties against Escherichia coli and Staphylococcus aureus by increasing linalool ratios. A significant decrease in antibacterial adhesion of 63% and 82% was observed for E. coli and S. aureus, respectively.

Thyme and suico essential oils: promising natural tools for potato common scab control

Potato common scab is a worldwide disease mainly caused by Streptomyces scabiei. It seriously affects potato crops by decreasing tuber quality. Essential oils (EO) are natural products with recognised antimicrobial properties. In this research, the antibacterial activities of thyme, oregano, suico and mint EO against S. scabiei were analysed. Infected tubers and soil samples were used for bacterial isolation; the obtained isolates were genetically identified. The chemical composition of the EO was determined by GC-MS. The broth microdilution method was used to analyse antibacterial properties of EO. Thirty-one bacterial isolates were obtained. The isolate chosen for antibacterial assays was morpho-physiologically and genetically identified as S. scabiei. Thyme EO was mainly composed of thymol and o-cymene; suico EO of dihydrotagetone, trans-tagetone and verbenone; oregano EO of trans-sabinene hydrate, thymol and ɣ-terpinene; and mint EO of menthone and menthol. All the EO tested were effective against S. scabiei, but thyme and suico EO were the most successful, with a minimum inhibitory concentration of 0.068 g·l^-1 and 0.147 g·l^-1 , respectively, and a minimum bactericidal concentration of 0.137 g·l^-1 and 0.147 g·l^-1 , respectively. Scanning electron microscopy showed similar damage caused by both thyme and suico EO to the bacterial envelope. Total phenolic content of EO was not related to their antibacterial activity. Thyme and suico EO are effective antibacterial agents against S. scabiei, impeding bacterial viability and disturbing the bacterial cell envelope. These EO are promising tools for control of potato common scab.

Combined Action of Piperitenone Epoxide and Antibiotics Against Clinical Isolates of Staphylococcus aureus and Escherichia coli

The aim of this study was to determine the antimicrobial efficiency of piperitenone epoxide (PEO) - a principal component of various aromatic plants' essential oil - in combination with various antibiotics against 28 strains of Staphylococcus aureus and 10 strains of Escherichia coli isolated from clinical samples. Mentha spicata's essential oil, initially collected by hydrodistillation, was then subjected to flush column chromatography affording PEO of high purity. Minimum inhibitory concentrations of PEO alone and in combination with various concentrations of antibiotics were assessed using the microdilution method. The combined action was estimated calculating the fractional inhibitory concentration (FIC) index from checkerboard assays. Our results showed that the average minimum inhibitory concentration (mg/l) of PEO alone against E. coli was 512 ± 364.7 μg/ml, which was significantly higher than 172.8 ± 180.7 μg/ml observed for S. aureus. From checkerboard assays, FIC values below the 0.5 index, indicating synergy, were observed for 59% of the drugs tested. Twelve percent of FIC index values were between 0.5 and 1, indicating additive effects, while 21% were indifferent. According to our results, PEO could be a promising antimicrobial compound when combined with specific antibiotics and deserves further study.

Antimicrobial Activity of Hybrids Terpolymers Based on Magnetite Hydrogel Nanocomposites

In the past few years, the development of hydrogel properties has led to the emergence of nanocomposite hydrogels that have unique properties that allow them to be used in various different fields and applications such as drug delivery, adsorption soil containing, tissue engineering, wound dressing, and especially antimicrobial applications. Thus, this study was conducted in order to fabricate a novel crosslinked terpolymer nanocomposite hydrogel using the free radical copolymerization method based on the usage of 2-acrylamido-2-methylpropane sulfonic acid (AMPS), acrylamide (AAm), acrylonitrile (AN), and acrylic acid (AA) monomers and iron oxide (Fe3O4) magnetic nanoparticles and using benzoyl peroxide as an initiator and ethylene glycol dimethacrylate (EGDMA) as a crosslinker. The structure of the synthesized composite was confirmed using Fourier transform infrared (FTIR) spectroscopy and x-ray powder diffraction (XRD) measurements. Furthermore, the surface morphology and the magnetic nanoparticle distributions were determined by scanning electron microscopy (SEM) measurement. In addition, the swelling capacity of the hydrogel nanocomposite was measured using the swelling test. Lastly, the efficiency of the produced composite was evaluated as an antimicrobial agent for Gram-positive and Gram-negative bacterial strains and a fungal strain.

Anti-Haemophilus Activity of Selected Essential Oils Detected by TLC-Direct Bioautography and Biofilm Inhibition

Essential oils (EOs) are becoming increasingly popular in medical applications because of their antimicrobial effect. Direct bioautography (DB) combined with thin layer chromatography (TLC) is a screening method for the detection of antimicrobial compounds in plant extracts, for example, in EOs. Due to their lipophilic character, the common microbiological assays (etc. disk diffusion) could not provide reliable results. The aim of this study was the evaluation of antibacterial and anti-biofilm properties of the EO of cinnamon bark, clove, peppermint, thyme, and their main components against Haemophilus influenzae and H. parainfluenzae. Oil in water (O/W) type Pickering nano-emulsions stabilized with silica nanoparticles from each oil were prepared to increase their water-solubility. Samples with Tween80 surfactant and absolute ethanol were also used. Results showed that H. influenzae was more sensitive to the EOs than H. parainfluenzae (except for cinnamon bark oil). In thin layer chromatography-direct bioautography (TLC-DB) the ethanolic solutions of thyme oil presented the best activity against H. influenzae, while cinnamon oil was the most active against H. parainfluenzae. Pickering nano-emulsion of cinnamon oil inhibited the biofilm formation of H. parainfluenzae (76.35%) more efficiently than samples with Tween80 surfactant or absolute ethanol. In conclusion, Pickering nano-emulsion of EOs could inhibit the biofilm production effectively.

Design and study of anticaries effect of different medicinal plants against S.mutans glucosyltransferase

BACKGROUND

The present study was aimed to evaluate the molecular level anticaries effect of different medicinal plants against Streptococcus mutans (S.mutans) glucosyltransferases (gtf).

METHODS

A total of six natural sources named as Terminalia chebula (T.chebula), Psidium guajava (P.guajava), Azadirachta indica (A.indica) and Pongamia pinnata (P.pinnata); two essential oils, clove (Syzygium aromaticum) and peppermint oil (Mentha piperita) were selected as test samples. Hydroalcoholic plant extracts and essential oils were examined for their inhibitory potential on gtf isolated from S.mutans. Polyherbal mouth wash was prepared and its effect on gtf activity was compared with commercial chlorhexidine mouth wash (5%w/v). Enzyme kinetic study was carried out in order to explore the molecular mechanism of enzyme action.

RESULTS

Out of six natural sources tested, A.indica has shown maximum inhibitory effect of 91.647% on gtf and T.chebula has shown IC50 of 1.091 mg/ml which is significant when compared to standard chlorhexidine. From the final result of kinetic analysis it was found that T.chebula, P.guajava and P.pinnata have show uncompetitive inhibition where as A.indica has shown non-competitive inhibition. Surprisingly, both essential oils have shown allosteric inhibition (sigmoidal response). The polyherbal moutwash has shown significant inhibitory potential on gtf (95.936%) when compared to commercial chlorhexidine mouthwash (p < 0.05).

CONCLUSION

All the tested samples have shown considerable gtf inhibitory action. Moreover polyherbal mouth wash has shown promising noncompetitive inhibitory activity against gtf and it could be the future formulation to combat dental caries.

Bioactive potential of fruit and vegetable wastes

Fruits and vegetables are essential for human nutrition, delivering a substantial proportion of vitamins, minerals, and fibers in our daily diet. Unfortunately, half the fruits and vegetables produced worldwide end up as wastes, generating environmental issues caused mainly by microbial degradation. Most wastes are generated by industrial processing, the so-called by-products. These by-products still contain many bioactive compounds post-processing, such as macronutrients (proteins and carbohydrates) and phytochemicals (polyphenols and carotenoids). Recently, the recovery of these bioactive compounds from industry by-products has received significant attention, mainly due to their possible health benefits for humans. This chapter focuses on the bioactive potential of fruit and vegetable by-products with possible applications in the food industry (functional foods) and in the health sector (nutraceuticals).

Analysis of Chemical Composition and Assessment of Cytotoxic, Antimicrobial, and Antioxidant Activities of the Essential Oil of Meriandra dianthera Growing in Saudi Arabia

The essential oil of Meriandra dianthera (Konig ex Roxb.) Benth. (Synonym: Meriandra bengalensis, Lamiaceae) collected from Saudi Arabia was studied utilizing GC and GC/MS. Forty four constituents were identified, representing 96.8% of the total oil. The M. dianthera essential oil (MDEO) was characterized by a high content of oxygenated monoterpenes (76.2%). Camphor (54.3%) was the major compound in MDEO followed by 1,8-cineole (12.2%) and camphene (10.4%). Moreover, MDEO was assessed for its cytotoxic, antimicrobial, and antioxidant activities. MDEO demonstrated an interesting cytotoxic activity against all cancer cell lines with IC₅₀ values of 83.6 to 91.2 μg/mL, especially against MCF-7 cancer cells. Using labeling with annexin VFITC and/or propidium iodide (PI) dyes and flow cytometer analysis, the apoptosis induction was quantitatively confirmed for MCF-7 cells. The MDEO exhibited a considerable antimicrobial activity against all bacterial and fungal strains with minimum inhibitory concentration (MIC)-values of 0.07 to 1.25 mg/mL. The most sensitive microbial strain was Staphylococcus aureus (MIC: 0.07 mg/mL). Minimum bactericidal concentration (MBC) or minimum fungicidal concentration (MFC) values were determined one time higher than that of MIC’s. Additionally, the MDEO revealed a strong activity for reducing β-carotene bleaching with a total antioxidant value of 72.6% and significant DPPH free radical scavenging activity (78.4%) at the concentration 1000 μg/mL.

Essential Oils as Antimicrobial Agents-Myth or Real Alternative?

Herbs and the essential oils derived from them have been used from the beginning of human history for different purposes. Their beneficial properties have been applied to mask unpleasant odors, attract the attention of other people, add flavor and aroma properties to prepared dishes, perfumes, and cosmetics, etc. Herbs and essential oils (EOs) have also been used in medicine because of their biological properties, such as larvicidal action, analgesic and anti-inflammatory properties, antioxidant, fungicide, and antitumor activities, and many more. Many EOs exhibit antimicrobial properties, which is extremely important in fields of science and industry, such as medicine, agriculture, or cosmetology. Among the 250 EOs which are commercially available, about a dozen possess high antimicrobial potential. According to available papers and patents, EOs seem to be a potential alternative to synthetic compounds, especially because of the resistance that has been increasingly developed by pathogenic microorganisms. In this review we summarize the latest research studies about the most-active EOs that are known and used because of their antimicrobial properties. Finally, it is noteworthy that the antimicrobial activities of EOs are not preeminent for all strains. Further investigations should, thus, focus on targeting EOs and microorganisms.

Antifungal activity of selected essential oils against Fusarium culmorum and F. graminearum and their secondary metabolites in wheat seeds

Essential oils (EOs) are products of plant origin and include mixtures of different chemical compounds. These volatile substances have many interesting properties, including antifungal properties. Fungi may develop under field conditions on crops such as wheat or corn and are able to synthesize mycotoxins, which adversely affect livestock and human health. In the present study, selected EOs were used to inhibit the growth of Fusarium graminearum and F. culmorum and reduce the concentrations of mycotoxins in wheat grain. The EOs significantly inhibited the growth of tested Fusarium species (90.99-99.99%), as determined based on ergosterol quantitative analysis. Only the addition of orange oil to F. culmorum exhibits a different inhibition capacity (68.13%). EO application resulted in a large reduction in zearalenone content (99.08-99.99%); only in the case of orange oil application was the reduction estimated at approximately 68.33%. However, all EOs provided a significant reduction in the concentration levels of group B trichothecenes (94.51-100%). It can be concluded that EOs inhibit the growth of fungi of the genus Fusarium and reduce concentration levels of the mycotoxins zearalenone and group B trichothecenes.

Electrospun Antimicrobial Films of Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) Containing Eugenol Essential Oil Encapsulated in Mesoporous Silica Nanoparticles

The main goal of this study was to develop poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) films with long-term antimicrobial capacity of interest in food packaging applications. To this end, eugenol was first highly efficiently encapsulated at 50 wt.-% in the pores of mesoporous silica nanoparticles by vapor adsorption. The eugenol-containing nanoparticles were then loaded in the 2.5⁻20 wt.-% range into PHBV by electrospinning and the resultant electrospun composite fibers were annealed at 155 °C to produce continuous films. The characterization showed that the PHBV films filled with mesoporous silica nanoparticles containing eugenol present sufficient thermal resistance and enhanced mechanical strength and barrier performance to water vapor and limonene. The antimicrobial activity of the films was also evaluated against foodborne bacteria for 15 days in open vs. closed conditions in order to simulate real packaging conditions. The electrospun PHBV films with loadings above 10 wt.-% of mesoporous silica nanoparticles containing eugenol successfully inhibited the bacterial growth, whereas the active films stored in hermetically closed systems increased their antimicrobial activity after 15 days due to the volatile portion accumulated in the system's headspace and the sustained release capacity of the films. The resultant biopolymer films are, therefore, potential candidates to be applied in active food packaging applications to provide shelf life extension and food safety.

The influence of air-dispersed essential oils from lemon (Citrus limon) and silver fir (Abies alba) on airborne bacteria and fungi in hospital rooms

Airborne bacteria and fungi are an ongoing problem in hospitals. Because of the antimicrobial activities of essential oils (EOs) dispersion of EOs into the air may help to reduce this contamination. The aim of this study was to evaluate the efficacy of the dispersion of selected EOs in reducing the microbial contamination in two hospital wards. The study was carried out at two wards of a 1,227-bed acute-care hospital in Austria. The concentration of airborne bacteria and fungi was measured in patient rooms before and after dispersion of a mixture of Citrus limon EO and Abies alba EO. Before dispersion of the EOs in both wards the mean concentration of bacteria was in a typical range (123 colony forming units (CFU) m^-3 and 104 CFU m^-3) while the mean concentration of fungi differed substantially (155 CFU m^-3 and 28 CFU m^-3). After dispersion of the EOs, a reduction in both bacterial and fungal contamination was observed. In the first two hours the mean concentration of airborne bacteria and fungi was reduced by approximately 40% and 30%-60% respectively. The selected EO mixture is effective in reducing the microbial contamination of the indoor air.

Schinus molle essential oil as a potential source of bioactive compounds: antifungal and antibacterial properties

AIMS

The study was focused on the evaluation of antimicrobial activity in vitro of the essential oil (EO) of leaves from Schinus molle against bacteria and fungi of clinical importance in the search for the discovery of new active compounds.

METHODS AND RESULTS

The chemical composition of the S. molle EO was determined by gas chromatography/mass spectrometry and its antimicrobial effect was verified by broth microdilution method. The major compounds found were β-pinene (25·23%), epi-α-cadinol (21·29%), α-pinene (18·72%), myrcene (11·54%) and sabinene (5·02%). The EO showed significant antifungal activity against Paracoccidioides brasiliensis (39·06 μg ml^-1 ), weak action against Cryptococcus neoformans (625 μg ml^-1 ) and Trichophyton quinckeanum (625 μg ml^-1 ) and was inactive against Candida sp. In the analysis of the antibacterial action, the micro-organisms tested did not show sensitivity.

CONCLUSIONS

This study showed a promising result of S. molle volatiles against the fungus P. brasiliensis, which causes paracoccidioidomycosis (PCM), a systemic mycosis of great clinical importance in Latin America.

SIGNIFICANCE AND IMPACT OF THE STUDY

The results found here are novel and encourage investigations of the compounds present in this EO, which represents a source of molecules with potential use in the treatment of PCM.

Probiotics and plant-derived compounds as eco-friendly agents to inhibit microbial toxins in poultry feed: a comprehensive review

Some of pathogenic bacteria and fungi have the ability to produce fetal toxins which may be the direct causes of cytotoxicity or cellular dysfunction in the colonization site. Biological and non-biological environmental factors, challenge and microbes influence the effect of toxins on these pathogens. Modern research mentions that many natural materials can reduce the production of toxins in pathogenic microbes. However, researches that explain the mechanical theories of their effects are meager. This review aimed to discuss the ameliorative potential role of plant-derived compounds and probiotics to reduce the toxin production of food-borne microbes either in poultry bodies or poultry feedstuff. Moreover, studies that highlight their own toxicological mechanisms have been discussed. Adding natural additives to feed has a clear positive effect on the enzymatic and microbiological appearance of the small intestine without any adverse effect on the liver. Studies in this respect were proposed to clarify the effects of these natural additives for feed. In conclusion, it could be suggested that the incorporation of probiotics, herbal extracts, and herbs in the poultry diets has some beneficial effects on productive performance, without a positive impact on economic efficiency. In addition, the use of these natural additives in feed has a useful impact on the microbiological appearance of the small intestine and do not have any adverse impacts on intestinal absorption or liver activity as evidenced by histological examination.

Screening of antifungal activity of 12 essential oils against eight pathogenic fungi of vegetables and mushroom

The antifungal properties of 12 Eos, that is, Syzygium aromaticum, Pelargonium graveolens, Lavandula angustifolia, Cupresus sempervirens, Mentha piperita, Santolina chamaecyparissus, Citrus sinensis, Pogostemon patchouli, Thymus mastichina, Thymus vulgaris, Eucalyptus globulus and Rosmarinus officinalis, were screened. The influence of five doses of each EOs was tested against Botrytis cinerea, Sclerotinia sclerotiorum, Fusarium oxysporum, Phytophthora parasitica, Pythium aphanidermatum, Alternaria brassicae, Cladobotryum mycophilum and Trichoderma aggressivum f.sp. europaeum using disc-diffusion method. The mycelial growth inhibition and ED₅₀ were calculated. The chemical analysis of the EOs was analysed using gas chromatography-mass spectroscopy. A total of 58 compounds were identified in the 12 EOs. All essential oils (EOs) analysed showed antifungal activity against the test pathogens in the range of 5·32-100%. The inhibitory effect of oils showed dose-dependent activity on the tested fungus. Based on the ED₅₀ values, clove, rose geranium, peppermint and patchouli were the most effective. This study warrants further research into the practical use of EOs for the control of important myco- and phytopathogens in intensive horticulture.

SIGNIFICANCE AND IMPACT OF THE STUDY

Due to the serious damage caused by fungal pathogens of vegetables and mushrooms, it is necessary to search for integrated strategies of disease control. This study provides relevant information about the effects of 12 essential oils (EOs) against eight pathogens of agricultural interest, included mycopathogens with emphasis on the possible future application of the EOs as alternative antifungal agents.

Phytochemical analysis and evaluation of the cytotoxic, antimicrobial and antioxidant activities of essential oils from three Plectranthus species grown in Saudi Arabia

Background

Cancers and microbial infections are still a major health problem, therefore research on new anticancer and antimicrobial agents ought to be continued. Natural products including essential oils from medicinal plants continue to be an important resource to manage various diseases. Thus, the particular objectives of this study are to investigate the chemical composition, cytotoxic, antimicrobial and antioxidant activities of three Plectranthus species namely P. cylindraceus Hocst. ex Benth., P. asirensis JRI Wood and P. barbatus Andrews grown in Saudi Arabia.

Methods

The essential oils of the three Plectranthus species were obtained by hydrodistllation and analyzed using GC/FID and GC-MS. The essential oils were further assessed for their cytotoxic, antimicrobial and antioxidant activities. Determination of the cytotoxic activity was carried out against Hela, HepG2 and HT-29 cancer cell lines by utilizing MTT-assay. The antimicrobial activity was assessed against six bacterial and fungal strains by using broth micro-dilution assay. In addition, the antioxidant activity was evaluated utilizing the DPPH and β-Carotene-linoleic acid assays.

Results

The GC/FID and GC-MS analysis led to the identification of 59, 60 and 42 compounds representing 89.0% 95.0 and 97.1% of the total essential oils of P. cylindraceus, P. asirensis and P. barbatus, respectively. The essential oils were characterized by a high content of oxygenated sesquiterpenes in P. cylindraceus, sesquiterpene hydrocarbons in P. asirensis and monoterpene hydrocarbons in P. barbatus where maaliol (42.8%), β-caryophyllene (13.3%) and α-pinene, (46.2%) were the predominant compounds. Additionally, the oils particularly of P. cylindraceus and P. barbatus exhibited remarkable cytotoxic and antimicrobial activities with IC₅₀-values between 3.8 and 7.5 μg/mL and MIC-values ranging from 0.137 to 4.40 mg/mL. Moreover, the oils showed moderate to high radical scavenging and antioxidative activities ranging from 52 to 75% at the highest concentration of 1 mg/mL.

Conclusions

The observed results back the suggestion that these three Plectranthus species represent a promising source of cytotoxic and antimicrobial agents.

Combination of Cloxacillin and Essential Oil of Melaleuca armillaris as an Alternative Against Staphylococcus aureus

The emergence of resistance to antibiotics has been favored by abuse in the application of antimicrobials in human and animal medicine. Essential oils are a great resource to deal with this crisis. Melaleuca armillaris belongs to the family of Myrtaceae, rich in species with essential oils. Plant extracts has shown antimicrobial activity in many investigations. Cloxacillin (CLOX) is an antibiotic widely used in veterinary medicine against Staphylococcus aureus. Our aim was to assess pharmacodynamic interaction established by combining essential oil of M. armillaris (EO) with CLOX in search of a synergistic effect that maximizes the antibacterial activity against S. aureus. The EO was obtained by steam distillation and its composition was analyzed by a GC-FID-MS. The most abundant components in the EO were 1.8 cineole (72.3%), limonene (7.8%). and α-pinene (6%). We worked with wild type S. aureus strains (n = 3) isolated from Holstein cows, and S. aureus ATCC 29213 as the reference strain. The Minimum Inhibitory Concentration (MIC) of CLOX, EO and the combination was determined by microdilution in broth at pH 7.4; 6.5 and 5.0. The checkerboard method was applied to evaluate the interaction between CLOX and EO. The Fractional Inhibitory Concentration index (FIC) was established. From those combinations that yielded the lowest FIC values, we evaluated the index of antibacterial activity (E), established as the difference between the Log₁₀ values of the number of viable bacteria at the initial (nt₀) and at the end of the test (nt₂₄). So, time-killing curves with CLOX and EO/CLOX combination at 0.5, 1, 2, 4, and 8 fold the MIC in broth at pH 7.4; 6.5 and 5.0 were prepared. We considered Bacteriostatic effect (E = 0) Bactericidal effect (E = -3) and Effect of virtual eradication of bacteria (E = -4). A clear synergic activity between the EO and the CLOX was demonstrated, which allows reducing the MIC of β-lactam against S. aureus. This interaction was favored by acidification of the medium, where lower concentrations of CLOX achieved a bactericidal effect, close to virtual eradication, in the presence of small amounts of EO.

Use of Pinus sylvestris L. (Pinaceae), Origanum vulgare L. (Lamiaceae), and Thymus vulgaris L. (Lamiaceae) essential oils and their main components to enhance itraconazole activity against azole susceptible/not-susceptible Cryptococcus neoformans strains

Background

Cryptococcal infections, besides being a problem for immunocompromised patients, are occasionally being a problem for immunocompetent patients. In addition, the lower susceptibility of this yeast to azoles is a growing problem in health care. To date, there are very few molecules with any activity towards Cryptococcus neoformans, leading to heightened interest in finding new alternatives or adjuvants to conventional drugs for the treatment of mycosis caused by this yeast. Since the essential oils (EOs) are considered as a potential rich source of bioactive antimicrobial compounds, we evaluated the antifungal activity of Origanum vulgare (oregano), Pinus sylvestris (pine), and Thymus vulgaris (thyme red) EOs, and their components (α-pinene, carvacrol, thymol) compared with fluconazole, itraconazole, and voriconazole, against C.neoformans clinical strains. Then, we investigated the effect of EOs and components in combination with itraconazole.

Methods

EO composition was analysed by Gas chromatography-mass spectrometry (GC-MS). A broth microdilution method was used to evaluate the susceptibility of C.neoformans to azoles, EOs and components. Checkerboard tests, isobolograms and time-kill assays were carried out for combination studies.

Results

Six C.neoformans isolates were susceptible to azoles, while one C.neoformans exhibited a reduced susceptibility to all tested azole drugs. All EOs exerted a good inhibitory activity against all C.neoformans strains. Pine EO was the most effective. Among components, thymol exerted the most remarkable activity. By checkerboard testing and isobolographic analysis, combinations of itraconazole with oregano, pine, or thyme EOs, and carvacrol were found to be synergistic (FICI≤0.5) against azole susceptible C.neoformans. Regarding the azole not susceptible C.neoformans strain, the synergistic effect with itraconazole was observed with thyme EO (chemotype: thymol 26.52%; carvacrol 7.85%), and carvacrol. Time-kill assays confirmed the synergistic effects of itraconazole and oregano or thyme EO against azole susceptible C.neoformans. Binary mixtures of itraconazole/thyme EO or carvacrol yielded additive effects on the azole not susceptible C.neoformans.

Conclusions

Our findings highlight the potential effectiveness of thyme, oregano EOs, and carvacrol as natural and cost-effective adjuvants when used in combination with itraconazole. Identification of EOs exerting these effects could be one of the feasible ways to overcome drug resistance, reducing drug concentration and side effects.

Natural actives for wound healing: A review

Nature has been a source of medicinal treatments for thousands of years, with the use of plants as prototypes for drug development and for the extraction of active compounds. Skin injuries occur regularly in everyday life, and the human skin has the ability to promote repair spontaneously under healthy conditions. However, some intrinsic and external factors may interfere with skins' natural ability, leading to nonhealing lesions and chronic wounds, which directly affect health and quality of life. Thus, attention should be given to this health problem, using an appropriated management when necessary. In this scenario, phytotherapy may be an option for cutaneous wound treatment, although further high-quality studies are needed to firmly establish the clinical efficacy of plants. This article reviews traditionally used natural actives for wound healing, highlighting their characteristics and mode of action.

In - Vitro activity of Desmostachya bipinnata (L.) Stapf successive extracts against Helicobacter pylori clinical isolates

Helicobacter pylori are well acknowledged as a major cause of gastrointestinal ailments and gastric cancers. Therefore, the present study aimed to investigate the potential in vitro activity of Desmostachya bipinnata against H. pylori, focusing on the determination of the most active extract responsible for the anti-helicobacter activity to produce new active drug from natural source. Desmostachya bipinnata total alcohol and successive extracts were in vitro tested against H. pylori. All extracts showed promising anti Helicobacter pylori activities. The most effective extract was diethyl ether extract, it showed 75% growth inhibition of the clinical Isolates bacterial Helicobacter pylori, in addition it showed high count reduction on the selected organisms in the different concentrations used (2xMIC, MIC & ½ MIC) compared with the untreated controls as well as the other extracts (chloroform, ethyl acetate and n-butanol). The oral median lethal dose (LD50) of the alcohol extract of the plant by doses up to 5000 mg/kg didn't showed any mortality or morbidity, in addition no side effects were recorded on both liver and kidney functions this means that the extract was safe for use.

Essential oils and their components are a class of antifungals with potent vapour-phase-mediated anti-Candida activity

Multi-resistant microorganisms continue to challenge medicine and fuel the search for new antimicrobials. Here we show that essential oils and their components are a promising class of antifungals that can have specific anti-Candida activity via their vapour-phase. We quantify the vapour-phase-mediated antimicrobial activity (VMAA) of 175 essential oils and 37 essential oil components, representing more than a 1,000 unique molecules, against C. albicans and C. glabrata in a novel vapour-phase-mediated susceptibility assay. Approximately half of the tested essential oils and their components show growth-inhibitory VMAA. Moreover, an average greater activity was observed against the intrinsically more resistant C. glabrata, with essential oil component citronellal having a highly significant differential VMAA. In contrast, representatives of each class of antifungals currently used in clinical practice showed no VMAA. The vapour-phase-mediated susceptibility assay presented here thus allows for the simple detection of VMAA and can advance the search for novel (applications of existing) antimicrobials. This study represents the first comprehensive characterisation of essential oils and their components as a unique class of antifungals with antimicrobial properties that differentiate them from existing antifungal classes.

Chemical composition and in-vitro antioxidant and antimicrobial activity of the essential oil of Citrus aurantifolia L. leaves grown in Eastern Oman

Objectives

This study investigated the chemical composition and the antioxidant and antimicrobial activities of the essential oil isolated from the aerial parts of Citrus aurantifolia L.

Methods

Fresh Citrus aurantifolia L. leaves were collected from farms in Sur city, located in the Al-Sharqia (Eastern) region of the Sultanate of Oman, during June-July of 2015. The essential oil was isolated using hydrodistillation. Gas chromatography-mass spectrometry (GC-MS) was used to identify and quantify the chemical constituents of the oil. An in-vitro 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging method was used to determine the antioxidant activity of the isolated oil from the lime leaves while a disc diffusion method was used to evaluate the antibacterial activity against Gram-negative and Gram-positive bacteria.

Results

Thirty-three chemical compounds were identified, with d-limonene (63.35%) forming the major constituent. Other prominent constituents include 3,7-dimethyl-2,6-octadien-1-ol (7.07%), geraniol (6.23%), E-citral (4.35%), Z-citral (3.29%), and β-ocimene (2.25%). The essential oil of Citrus aurantifolia L. leaves showed excellent antibacterial activity against Staphylococcus aureus and moderate activity against pathogenic Escherichia coli strains. The oil exhibited promising in-vitro antioxidant activity (IC₅₀ value = 21.57 μg/mL) but showed moderate antibacterial activities.

Conclusions

The essential oil from Omani lime leaves is characterized by a high d-limonene content, making it useful for food, pharmaceutical, and perfumery industries.

Synchronous application of antibiotics and essential oils: dual mechanisms of action as a potential solution to antibiotic resistance

Antibiotic resistance has increased dramatically in recent years, yet the antibiotic pipeline has stalled. New therapies are therefore needed to continue treating antibiotic resistant infections. One potential strategy currently being explored is the use of non-antibiotic compounds to potentiate the activity of currently employed antibiotics. Many natural products including Essential Oils (EOs) possess broad spectrum antibacterial activity and so have been investigated for this purpose. This article aims to review recent literature concerning the antibacterial activity of EOs and their interactions with antibiotics, with consideration of dual mechanisms of action of EOs and antibiotics as a potential solution to antibiotic resistance. Synergistic interactions between EOs and their components with antibiotics have been reported, including several instances of antibiotic resensitization in resistant isolates, in support of this strategy to control antibiotic resistance. However, a lack of consistency in methods and interpretation criteria makes drawing conclusions of efficacy of studied combinations difficult. Synergistic effects are often not explored beyond preliminary identification of antibacterial interactions and mechanism of action is rarely defined, despite many hypotheses and recommendations for future study. Much work is needed to fully understand EO-antibiotic associations before they can be further developed into novel antibacterial formulations.

Chemical Composition and Bioactivity of Essential Oil from Blepharocalyx salicifolius

Natural products represent a source of biologically active molecules that have an important role in drug discovery. The aromatic plant Blepharocalyx salicifolius has a diverse chemical constitution but the biological activities of its essential oils have not been thoroughly investigated. The aims of this paper were to evaluate in vitro cytotoxic, antifungal and antibacterial activities of an essential oil from leaves of B. salicifolius and to identify its main chemical constituents. The essential oil was extracted by steam distillation, chemical composition was determined by gas chromatography/mass spectrometry, and biological activities were performed by a microdilution broth method. The yield of essential oil was 0.86% (w/w), and the main constituents identified were bicyclogermacrene (17.50%), globulol (14.13%), viridiflorol (8.83%), γ-eudesmol (7.89%) and α-eudesmol (6.88%). The essential oil was cytotoxic against the MDA-MB-231 (46.60 μg·mL⁻¹) breast cancer cell line, being more selective for this cell type compared to the normal breast cell line MCF-10A (314.44 μg·mL⁻¹). Flow cytometry and cytotoxicity results showed that this oil does not act by inducing cell death, but rather by impairment of cellular metabolism specifically of the cancer cells. Furthermore, it presented antifungal activity against Paracoccidioides brasiliensis (156.25 μg·mL⁻¹) but was inactive against other fungi and bacteria. Essential oil from B. salicifolius showed promising biological activities and is therefore a source of molecules to be exploited in medicine or by the pharmaceutical industry.

Phytochemical Composition and Biological Activities of Dyssodia tagetiflora Lag

While plants of the genus Dyssodia are used by man to a certain extent, few phytochemical and pharmacological studies have been performed with species of this genus. D. tagetiflora is an endemic plant of Mexico and has been used as fodder. The aim of this research was to isolate and identify the main bioactive components and evaluate the insecticidal, antioxidant, genotoxic and cytoprotective activities of D. tagetiflora. The isolated substances included an essential oil composed of six monoterpenes, and extracts containing two flavonols, three flavonol-glycosides and four thiophenes. The compounds were characterized using spectroscopic and spectrometric methods, including GC/MS, MS and NMR. The essential oil showed insecticidal activity against Drosophila melanogaster larvae. The methanolic extract of D. tagetiflora (DTME) had strong antioxidant activity against DPPH and ABTS radicals; DTME showed no evidence of genotoxic or cytotoxic effects. In contrast, DTME showed a cytoprotective effect attenuating the formation of H₂ O₂ -induced micronuclei in Vicia faba roots. This report is the first to describe the phytochemical and biological activity of D. tagetiflora.

Essential Oils and Antifungal Activity

Since ancient times, folk medicine and agro-food science have benefitted from the use of plant derivatives, such as essential oils, to combat different diseases, as well as to preserve food. In Nature, essential oils play a fundamental role in protecting the plant from biotic and abiotic attacks to which it may be subjected. Many researchers have analyzed in detail the modes of action of essential oils and most of their components. The purpose of this brief review is to describe the properties of essential oils, principally as antifungal agents, and their role in blocking cell communication mechanisms, fungal biofilm formation, and mycotoxin production.

A review on influencing factors on the minimum inhibitory concentration of essential oils

With growing interest in essential oils as natural preservatives in the food industry, the literature is expanding enormously. To understand the antimicrobial activity of essential oils, the antimicrobial mechanism of individual essential oil (EO) compounds, and their minimum inhibitory concentrations (MICs), are interesting starting points for research. Therefore, and to get insight into the factors influencing their antimicrobial activities, the Web of Science was searched for MICs of EO compounds (1995-2016). Many MICs for individual EO compounds have already been reported in the literature, but there is large variability in these data, even for the MIC of the same compound against the same species. No correlation was found between the tested structural parameters of EO compounds (polarity, water solubility, dissociation constant, molecular weight and molecular complexity) and their MICs against all microorganisms, Gram-negative bacteria, Gram-positive bacteria and fungi. Few clear differences in sensitivity between microorganisms could be found. Based on this review it is clear that different incubation conditions, culture media and the use of emulsifiers/solvents have an influence on the MIC, causing big variance. This review points out the need for a good international standard method to assess the antimicrobial activity of EO compounds for better comparability between studies.

Chemical composition, anti-biofilm activity and potential cytotoxic effect on cancer cells of Rosmarinus officinalis L. essential oil from Tunisia

Background

Rosmarinus officinalis L. from Tunisia, popularly known as rosemary, is of a considerable importance for its medicinal uses and aromatic value. The aim of this study was to examine the chemical composition of Rosmarinus officinalis essential oil (ROEO) and to evaluate its antibiofilm activity on biofilm-forming bacterium and its anticancer activity on cancer cell lines.

Methods

The chemical composition of Rosmarinus officinalis essential oil (ROEO) was analyzed by GC-MS and its antibacterial activity was evaluated by micro-dilution method. The antibofilm activity of ROEO was evaluated using the crystal violet test and the cytotoxicity activity was determined by the MTT assay.

Results

In this research, thirty-six compounds were identified in ROEO using GC-MS analyses. The main components were 1,8-cineole (23.56%), camphene (12.78%), camphor (12.55%) and β-pinene (12.3%). The antibacterial activity of ROEO was evaluated by micro-dilution method. The oil exhibited inhibition and bactericidal effect against two strains: Staphylococcus aureus ATCC 9144 and Staphylococcus epidermidis S61. It was found that the minimum inhibitory concentration (MIC) obtained for S. aureus and S. epidermidis ranged from 1.25 to 2.5 and from 0.312 to 0.625 μl ml⁻¹, respectively and the minimum bactericidal concentration (MBC) were in the order of 5 and 2.5 μl ml⁻¹, respectively. Furthermore, this oil showed a S. epidermidis biofilm inhibition more than 57% at a concentration of 25 μl ml⁻¹. The eradication of 67% of the established biofilm was observed at a concentration of 50 μl ml⁻¹ of ROEO, whereas the dose of 25 μl ml⁻¹ removed only 38% of preformed biofilm. ROEO strongly inhibited the proliferation of Hela and MCF-7 cells with IC₅₀ values of 0.011 and 0.253 μl ml⁻¹, respectively.

Conclusion

Our results demonstrate that ROEO could have a potential role in the treatment of diseases related to infection by microorganisms or proliferation of cancer cells.

Diagnosis and treatment of dermatophytosis in dogs and cats.: Clinical Consensus Guidelines of the World Association for Veterinary Dermatology

BACKGROUND

Dermatophytosis is a superficial fungal skin disease of cats and dogs. The most common pathogens of small animals belong to the genera Microsporum and Trichophyton. It is an important skin disease because it is contagious, infectious and can be transmitted to people.

OBJECTIVES

The objective of this document is to review the existing literature and provide consensus recommendations for veterinary clinicians and lay people on the diagnosis and treatment of dermatophytosis in cats and dogs.

METHODS

The authors served as a Guideline Panel (GP) and reviewed the literature available prior to September 2016. The GP prepared a detailed literature review and made recommendations on selected topics. The World Association of Veterinary Dermatology (WAVD) provided guidance and oversight for this process. A draft of the document was presented at the 8th World Congress of Veterinary Dermatology (May 2016) and was then made available via the World Wide Web to the member organizations of the WAVD for a period of three months. Comments were solicited and posted to the GP electronically. Responses were incorporated by the GP into the final document.

CONCLUSIONS

No one diagnostic test was identified as the gold standard. Successful treatment requires concurrent use of systemic oral antifungals and topical disinfection of the hair coat. Wood's lamp and direct examinations have good positive and negative predictability, systemic antifungal drugs have a wide margin of safety and physical cleaning is most important for decontamination of the exposed environments. Finally, serious complications of animal-human transmission are exceedingly rare.

Chemical composition and evaluation of the antibacterial and Cytotoxic activities of the essential oil from the leaves of Myracrodruon urundeuva

BACKGROUND

This study evaluated the in vitro activity of essential oil extracted from the leaves of Myracrodruon urundeuva.

METHODS

The oil was obtained by hydro-distillation and characterized by Gas Chromatography coupled to Mass Spectrometry (GC-MS) and Gas Chromatography with Flame Ionization Detector (GC-FID). The antibacterial activity was evaluated by the broth microdilution technique and the MIF was determined by using growth indicator CTT (2,3,5-triphenyl-tetrazolium) and CBM in BHI agar. The oil's cytotoxicity was evaluated in HeLa, HEK-293, and Vero E6 cells using MTT, 3- (4,5-dimethylthiazol-2-yl) -2,5-diphenyl tetrazolium.

RESULTS

The oil showed chemical markers, including α-pinene (87.85%), trans-caryophyllene (1.57%), limonene (1.49%) and β -pinene (1.42%), and activity against all strains: Staphylococcus aureus (MIC = MBC = 0.22 mg/mL), Staphylococcus epidermidis (MIC = 0.11 mg/mL and MBC = 0.22 mg/mL), Escherichia coli (MIC = 0.88 mg/mL and MBC = 1.75 mg/mL), Pseudomonas aeruginosa (MIC = MBC = 7 mg/mL) and Salmonella Enteritidis (MIC = MBC = 0.44 mg/mL). In vitro cytotoxicity tests showed that the oil is not toxic and has slight antitumor activity.

CONCLUSIONS

We conclude that the M. urundeuva oil results are promising, with prospects of being pharmacologically viable.

Exploring the Potentials of Lysinibacillus sphaericus ZA9 for Plant Growth Promotion and Biocontrol Activities against Phytopathogenic Fungi

There is an ongoing hunt for biologically active compounds that can combat phytopathogenic fungi and improve plant growth without causing any hazards to the environment. Consequently the present study aims at deciphering the plant growth promotion and antifungal capability of Lysinibacillus sphaericus ZA9. The bacterium was previously isolated and identified in our laboratory from maize rhizosphere using 16S rRNA gene sequencing. The test bacterium L. sphaericus ZA9 was found to produce high quantity of IAA (697 μg/ mL); siderophores (195.79 μg/ mL), HCN and hydrolytic enzyme as compared to the reference strain Bacillus sphaericus Z2-7. The bacterium was also capable of solubilizing silicates (Si), phosphates (P), and potassium (K). The bacterium enhanced the seedling vigor and germination of seeds pretreated with it and promoted the shoot length of both cucumber and tomato seeds in greenhouse experiment. L. sphaericus ZA9 and its cell free culture supernatant showed varied antagonistic behavior against Alternaria alternata, Curvularia lunata, Aspergillus sp., Sclerotinia sp., Bipolaris spicifera, Trichophyton sp. Fermentation broth culture of L. sphaericus ZA9 was then used to isolate antifungal metabolites by silica column chromatography. Identification and determination of antifungal compounds was carried out by Thin-layer chromatography (TLC) followed by NMR spectroscopy. Two compounds were isolated and identified as 2-pentyl-4-quinolinecarboxylic acid (C₁₅H₁₇NO₂) which is a quinoline alkaloid and 1- methylcyclohexene which is a cycloalkene. Compound 1; 2-Penthyl-4-quinolinecarboxylic acid was found to be highly antagonistic against most of the fungi tested as compared to the bacterium itself. Its activity was comparable to that of fungicide Benlate, while compound 2; 1- methylcyclohexene did not show any antifungal activity.