In vitro antimicrobial screening of Lycoperdon lividum and determination of the ethanol extract composition by gas chromatography/mass spectrometry
Abstract
The aim of this study was to investigate the antimicrobial activity of Lycoperdon lividum against 17 bacterial and 1 fungal strains and analyse the composition of ethanol extracts by GC/MS. The in vitro antimicrobial activity of L. lividum extracts having 15 mg/mL concentration was assessed against a wide range of strains by disk diffusion method. The ethanol extract of L. lividum had antimicrobial activity against several microorganism tested, but it was active especially against S. carnosus. The results obtained herein indicate that L. lividum contains several active metabolites.
Introduction
Although there is tremendous progress in human medicine; bacterial, viral and fungal issues are still threaten the public health especially in the developing countries (Cos et al., 2006). Relative unavailability of medicines in these countries and in addition to this the extensive antibiotic resistance has a large impact on human health (Okeke et al., 2005). Therefore, further researches about investigation of new antimicrobial substances should be conducted (Altuner et al, 2010).
Mushrooms have a potential of using both as nutritive and medicinal food stuff (Imtiaj and Lee, 2007; Bonatti et al., 2004; Cheung and Cheung, 2005; Agrahar-Murugkar and Subbulakshmi, 2005; Altuner et al., 2012). Mushrooms are not only sources of nutrients but also could be used to prevent diseases such as hypertension, hypercholesterolemia and cancer (Bobek and Galbavy, 1999).
Lycoperdon lividum Pers. grows on soil and dunes, solitary to gregarious, in forests, outside of forests, in meadows and cow pastures (Breitenbach and Kranzlin, 1986).
Researchers isolated and identified some compounds, originating from mushrooms; show other medicinal properties, such as immunemodulatory, liver protective, antifibrotic, antiinflammatory, antidiabetic, antiviral and antimicrobial activities (Wasser and Weis, 1999a-1999b; Gunde-Cimerman, 1999; Dulger et al., 1999; Ooi, 2000).
The aim of this study was to investigate the antimicrobial activity of L. lividum against 17 bacterial and 1 fungal strains and analyse the composition of ethanol extracts by GC/MS.
Materials and Methods
Fungi samples
L. lividum samples used in this study were collected from Trabzon, Yomra, Camliyurt village, in spruce forest, 40°44'N, 39°50'E, 1000 m, 22.09.2012, Akata 4702. Voucher specimens were deposited for further reference in Herbarium of Ankara University (ANK) Faculty of Science, Department of Biology, Ankara, Turkey.
Extraction procedure
L. lividum samples were air dried and samples were ground by a mortar and a pestle. In order to extract active substances, ground samples were shaken in ethanol (Merck, Germany) at 100 rpm for 3 days at room temperature. Then all the extracts were filtered through Whatman No. 1 filter paper into evaporation flasks. The filtrate was evaporated by a rotary evaporator (Heidolph Hei-Vap Value HL/HB-G1) at 30°C and lyophilized. After lyophilization the residues were collected and used to prepare 15 mg.mL-1 extracts.
Microorganisms
A wide range of bacteria (Gram positive and Gram negative) and yeast were selected to test the antimicrobial activity of L. lividium. The strains were chosen from standard strains as much as possible. Other strains which are not standard were all isolated from food and identified at the Department of Biology, Faculty of Science, Ankara University.
Bacillus subtilis ATCC 6633, Candida albicans ATCC 10231, Enterobacter aerogenes ATCC13048, Enterococcus durans, E. faecalis ATCC 29212, E. faecium, Escherichia coli ATCC 25922, E. coli CFAI, Klebsiella pneumoniae, Listeria monocytogenes ATCC 7644, Salmonella enteritidis ATCC 13075, S. infantis, S. kentucky, S. typhimurium SL 1344, Staphylococcus aureus ATCC 25923, S. carnosus MC1.B, S. epidermidis DSMZ 20044 and Streptococcus agalactiae DSMZ 6784 were used in the study.
Prepartion of inocula
All bacterial strains were incubated at 37°C for 24 hours. But since the requirements for C. albicans is different. C. albicans was incubated at 27°C for 48 hours. Inocula were prepared by transferring morphologically similar colonies of each organism into 0.9% sterile saline solution until the visible turbidity was equal to 0.5 McFarland standard having approximately 108 cfu/mL for bacteria and 107 cfu/L for C. albicans (Canli et al., 2015).
Disk diffusion method
Disk diffusion test was performed as described previously by Andrews (2003). The culture medium was poured into 120 mm sterile petri dish to give a mean depth of 4.0 ± 0.5 mm. 40, 60 and 100 µL aliquots of each extract was applied on sterile disks of 6 mm diameter end up with 550, 917 and 1375 µg sample on each disk. To get rid of any residual solvent which might interfere with the results, disks were left to dry overnight at 30°C in sterile conditions (Altuner et al., 2010). The surface of the plates was inoculated using previously prepared inocula containing saline suspension of microorganisms. Inoculated plates were then left to dry at room temperature before applying the disks. Disks were firmly applied to the surface of the plate which had an even contact with the agar (Savaroglu et al., 2011). Plates were incubated and inhibition zone diameters were expressed in millimetres.
Gas chromatography-mass spectrophotometry method (GC-MS)
The GC-MS analysis of etanol extract of LC were quantitatively performed by GC-MS (Agilent 19091S-433, 30 x 0.25 x 0.25 HPS MS) based on the method defined previously by Hossain and Rahman (2011) with some modifications. Split less injection was performed with a purge time of 1.0 min. The carrier gas was helium at a flow rate of 1 mL/min. The column temperature was maintained at 60°C for 2 min, then programmed at 10°C/min to 300°C and waited for 10 min. The inlet temperature was 250°C, AUX was 290°C and the solvent delay was 4 min. The identification of the peaks was based on computer matching of the mass spectra with the National Institute of Standards and Technology (NIST Mass Spectrometry DATA CENTER, 2005) library and by direct comparison with published data (Canlı et al., 2014).
Controls
Empty sterile disks and extraction solvent (ethanol) loaded on sterile disks which were dried at sterile conditions to remove solvent as done in the study were used as negative controls.
Statistics
The statistical analysis was performed using a non-parametric method Kruskal-Wallis one-way analysis of variance. A value of p<0.05 was considered statistically significant.
Results
The diameter of the inhibition zones identified as the diameter of the zones in millimetres for the samples are given in Table I. No activity was observed for the negative controls; solvents and empty sterile disks.
Table I: Disk diffusion test results (Inhibition zones in mm)
| 40 µL | 60 µL | 100 µL | |
|---|---|---|---|
| B. subtilis ATCC 6633 | - | - | - |
| C. albicans ATCC 10231 | - | - | - |
| E. aerogenes ATCC13048 | 7 | 7 | 7 |
| E. durans | - | - | - |
| E. faecalis ATCC 29212 | - | - | - |
| E. faecium | - | - | - |
| E. coli ATCC 25922 | 7 | 7 | 7 |
| E. coli CFAI | - | - | - |
| K. pneumoniae | 7 | 7 | 7 |
| L. monocytogenes ATCC 7644 | - | - | - |
| S. enteritidis ATCC 13075 | - | - | - |
| S. infantis | - | - | - |
| S. kentucky | 7 | 7 | 7 |
| S. typhimurium SL 1344 | - | - | - |
| S. aureus ATCC 25923 | - | - | - |
| S. carnosus MC1.B | 7 | 8 | 9 |
| S. epidermidis DSMZ 20044 | - | - | 7 |
| S. agalactiae DSMZ 6784 | - | 7 | 7 |
Table I clearly shows that ethanol extracts of L. lividum were presented antimicrobial activity against E. aerogenes, E. coli ATCC 25922, K. pneumoniae, S. kentucky, S. carnosus, S. epidermidis and S. agalactiae.
The GC-MS analysis of ethanol extract of L. lividum was identified and some of the chemical components found in the ethanol extract of L. lividum was isovaleric acid, pantoic lactone, pyrrolidinone, coumaran (2,3 dihydro benzofuran), 3-pyridine,1,2-proponediol, dihydroxytoluene, niacinamide, 3-piperidino-1,2 propanediol, isobutyl p-hydroxybenzoate, dodecanoic asit, metacetamol (paracetamol), ethyl quinoline, tetradecanoic acid, pentadecanoic acid, ethyl-13-methyltetradecanoate, hexadecanoic acid, 9-hexadecenoic acid, ethyl hexadecanoate, propanoic acid 3-mercaptododecyl ester, heptadecanoic acid, linoleic acid, ethyl linoleate, oleic asit, stearic acid, 2-monopalmitin, monolinolein, 2-mono stearin, dihydroergosterol and ergesterol.
Discussion
Results clearly show that L. lividiumis active against several microorganisms but its antimicrobial activity is notable especially against S. carnosus. Among the microorganisms affected by L. lividum extracts are E. coli, S. carnosus, S. Epidermidis, S. Agalactiae, E. aerogenes, S. kentucky and K. Pneumonia.
It is well-known that Gram negative bacteria are in general more resistant to a large number of antibiotics and chemotherapeutic agents than Gram positive bacteria (Nikaido, 1998).
We have observed that L. lividum had a low antimicrobial activity against E. aerogenes, E. coli, K. pneumoniae, S. kentucky, S. epidermidis and S. agalactiae, when it is compared to S. carnosus for the concentrations used in the study.
On the other hand, the chemical composition of L. livdium was analysed and several compounds, namely isovaleric acid, pantoic lactone, pyrrolidinone, coumaran (2,3 dihydro benzofuran), 3-pyridine,1,2-proponediol, dihydroxytoluene, niacinamide, 3-piperidino-1,2 propanediol, isobutyl p-hydroxybenzoate, dodecanoic asit, metacetamol (paracetamol), ethyl quinoline, tetradecanoic acid, pentadecanoic acid, ethyl-13-methyltetradecanoate, hexadecanoic acid, 9-hexadecenoic acid, ethyl hexadecanoate, propanoic acid 3-mercaptododecyl ester, heptadecanoic acid, linoleic acid, ethyl linoleate, oleic asit, stearic acid, 2-monopalmitin, monolinolein, 2-mono stearin, dihydroergosterol and ergesterol, in which some of them have been proved to have antimicrobial activity before.
Unfortunately there have been no reports neither about the antimicrobial activity of L. lividium, nor the chemical composition of its ethanol extract in order to compare with our results, as far as the current literature is concerned. Results presented in this study are the very first data both about the antimicrobial activity and the chemical composition of the ethanol extract of L. lividium.
E. aerogenes was identified as one of the "ICU bugs" which could cause significant mortality and morbidity. In addition the infection management is complicated due to its resistance to multiple antibiotics (Hidron et al., 2008). Although a very low activity was observed against E. aerogenes, the results can be accepted as noteworthy. Probably increasing amount of extracts loaded on the empty sterile antibiotic disks may increase the activity.
There are several studies reported by using differentE. coli strains. For example, Dulger et al. (2005) showed that the methanolic extract of Hypnum cupressiforme (30 mg/mL) presented 12.2 mm of inhibition zone against E. coli. When the results reported by Dulger et al. (2005) were compared with our results, which were maximum 7 mm inhibition zone, it can be concluded that L. lividum presented very low antimicrobial activity. But since the E. coli strain used in this study is different than the study conducted by Dulger et al. (2005), this difference is not surprising.
In addition it was also pointed out that Gram negative bacteria are the dominant killers among bacterial pathogens in the Intensive Care Units (ICU) (Villegas and Quinn, 2004). Klebsiella is one of these Gram negative microorganisms that cause death in ICUs (Villegas and Quinn, 2004).
From this point of view, having antibacterial activity against K. pneumoniae may very important. Quereshi et al. (2010) identified that Ganoderma lucidum (40 ug.mL-1) caused 11.30 mm of inhibition zone against K. pneumoniae. In our study we observed 7 mm of inhibition zone against L. lividum extract. By comparing these two studies it can be concluded that ethanolic extracts of L. lividum has lower antimicrobial activity against K. pneumoniae when compared to G. lucidum.
It was previously uncommon but in the last decade an increase was observed in S. kentucky cases especially in Northeast Africa and Turkey. This strain displays high-level resistance to ciprofloxacin, one of the drugs used against Salmonella infections. In addition, secondarily acquired resistances to extended-spectrum cephalosporin and trimethoprim + sulfamethoxazole was also observed (Collard et al., 2007)
S. epidermidis is not usually pathogenic. But they often develop risk for infection for patients with a compromised immune system. These infections can be both nosocomial and community acquired, but they pose a greater threat to hospital patients. S. epidermidis is also a major concern for people with catheters because it is known to cause biofilms that grow on these devices (Queck and Otto, 2008; Salyers et al., 2002).
Several researchs conducted on the antibacterial activity of several higher plants against S. epidermidis. Mahida and Mohan (2007) tested 10 mg of methanolic extracts of 23 plant extracts, but the highest zone was found to be 20 mm for Mangifera indica. In another study ethanol extracts of 23 plants were tested against S. epidermidis and the highest inhibition zone diameter was given as 18 mm for Stachys leptoclada (Sarac and Ugur, 2007).
Hexadecanoic acid, which is also known as palmitic acid, is the most common fatty acid found in animals, plants and microorganisms (Gunstone et al., 2007). It is mainly used to produce soaps and cosmetics. Hexadecanoic acid is also proposed as an antimicrobial agent in several researches (Glover et al., 1997; Risk et al, 1997; Bazes et al., 2009). Hexadecanoic acid also presented a significant antibacterial activity against S. mutans (Huang et al., 2011). In addition, it has antifungal activity against Alernaria solani (Liu et al., 2008), A. niger (Altieri et al., 2007), A. terreus (Altieri et al., 2007), Cucumerinum lagenarium (Liu et al., 2008), Emericella nidulans (Liu et al., 2008) and F. oxysporum (Liu et al., 2008).
Stearic acid is a saturated fatty acid having molecular formula C18H36O2. Stearic acid is mainly used in the production of detergents and cosmetics, but an antimicrobial activity potential against diverse pathogenic microorganism is also proposed in several studies (Zheng et al., 2005; Nalina and Rahim; 2007; Chakraborty and Shah, 2011).
Antimicrobial activity of linoleic acid was also determined in several researches. Tsuchida and Morishida (1995) investigated its antimicrobial activity against some Gram positive and Gram negative strains. They found that linoleic acid has high antimicrobial activity mostly against Gram positive strains. It also presented antimicrobial activity against B. larvae (Feldlaufer et al., 1993). It is also identified that linoleic acid is active against A. solani (Liu et al., 2008), C. albicans (Kabara et al., 1972), Crinipellis pernicosa (Walters et al., 2004), F. oxysporum (Liu et al., 2008), Pyrenophora avanae (Walters et al., 2004), Pythium ultimum and Rhizoctonia solani (Walters et al., 2004).
It is also previously reported that linoleic acid has antibacterial activity (Knapp and Melly, 1986; Kabara et al., 1972; Sun et al., 2003; Zheng et al., 2005) and antifungal activity against C. pernicosa, P. avanae, P. ultimum and R. solani (Walters et al., 2004).
On the other hand, there are several studies that show pantoyl lactone has antimicrobial activity, especially against S. equi (Bashir, 2013) and some pyrrolidinone derivatives present antimicrobial properties (Daferner et al., 2002).
Conclusion
We observed antimicrobial activity against E. aerogenes, E. coli, K. pneumoniae, S. kentucky, S. carnosus, S. epidermidis and S. agalactiae. The ethanol extract of L. lividum contains several active metabolites and it is active against several microorganisms. Its antimicrobial activity is notable especially against S. carnosus.
References
Agrahar-Murugkar D, Subbulakshmi G. Nutritional value of edible wild mushrooms collected from Khasi hills of Meghalaya. Food Chem. 2005; 89: 599-603.
Agoramoorthy G, Chandrasekaran M, Venkatesalu V, Hsu MJ. Antibacterial and Antifungal activities of fatty acid methyl esters of the Blind-Your-Eye Mangrove from India. Brazilian J Microbiol. 2007; 38: 739-42.
Altieri C, Cardillo D, Bevilacqua A, Singaglia M. Inhibition of Aspergillus ssp. and Penicillium spp. by fatty acids and their monoglycerides. J Food Protection. 2007; 70: 1206-12.
Altuner EM, Akata I, Canli K. In vitro antimicrobial screening of Cerena unicolor (Bull.) Murrill (Polyporaceae Fr. Ex Corda). Fresen Environ Bullet. 2012; 21(1B): 3704-3710.
Altuner EM, Cetin B, Cokmmus C. Antimicrobial activity of Tortella tortulosa (Hedw.) Limpr. Extracts. Kastamonu Univ J Forestry Faculty. 2010; 10: 111-16.
Andrews JM. BSAC standardized disk susceptibility testing method (version 6). J Antimicrob Chemother. 2003; 60: 20-41.
Bazes A, Silkina A, Douzenel P, Fay F, Kervarec N, Morin D, Berge JP and Bourgougnon N. Investigation of the antifouling constituents from the brown alga Sargassum muticum (Yendo) Fensholt. J Appl Phycol. 2009; 21: 395-403.
Bashir ZA. Antimicrobial plasma membrane activity of daptomycin and pantoyl lactone against Streptococcus equi. Int J Sci Res Publications. 2013; 3: 1-8.
Batovska DI, Todorova IT, Tsvetkova IV, Najdenski HM. Antibacterial study of the medium chain fatty acids and their 1-monoglycerides: Individual effects and synergistic relationship. Polish J Microbiol. 2009; 58: 43-47.
Bobek P, Galbavy S. Hypocholesterolemic and antiatherogenic effect of oyster mushroom (Pleurotus ostreatus) in rabbit. Nahrung 1999; 43: 339-42.
Bonatti M, Karnopp P, Soares HM, Furlan SA. Evaluation of Pleurotus ostreatus and Pleurotus sajorcaju nutritional characteristics when cultivated in different lignocelluloses wastes. Food Chem. 2004; 88: 425-28.
Breitenbach J, Kranzlin F. Fungi of Switzerland. Vol: 2. Nongilled Fungi, Verlag Mykologia CH-6000 Luzern 9, Switzerland, 1986.
Canli K, Altuner EM, Akata I. Antimicrobial screening of Mnium stellare. Bangladesh J Pharmacol. 2015; 10: 321-25.
Canli K, Cetin B, Altuner EM, Turkmen Y, Uzek U, Dursun H. In vitro antimicrobial screening of Hedwigia ciliata var. leucophaea and determination of the ethanol extract composition by gas chromatography/mass spectrometry (GC/MS). J Pure Appl Microbiol. 2014; 8: 2987-98.
Carballeira NM, O'Neil R, Parang K. Racemic and optically active 2-methoxy-4-oxatetradecanoic acids: Novel synthetic fatty acids with selective antifungal properties. Chem Physics Lipids. 2005; 136: 47-54.
Chakraborty D, Shah B. Antimicrobial, antioxidative and anti-hemolytic activity of Piper betel leaf extracts. Int J Pharm Pharmaceut Sci. 2011; 3, Suppl 3: 192-99.
Cheung LM, Cheung PCK. Mushroom extracts with antioxidant activity against lipid peroxidation. Food Chem. 2005; 89: 403-09.
Collard JM, Place S, Denis O, Rodriguez-Villalobos H, Vrints M, Weill FX, Baucheron S, Cloeckaert A, Struelens M, Bertrand S. Travel-acquired salmonellosis due to Salmonella Kentucky resistant to ciprofloxacin, ceftriaxone and co-trimoxazole and associated with treatment failure. J Antimicrob Chemother. 2007; 60: 190-92.
Cos P, Vlietinck AJ, Vanden Berghe D, Maes L. Anti-infective potential of natural products: How to develop a stronger in vitro "proof-of-concept". J Ethnopharmacol. 2006; 106: 290-302.
Daferner M, Anke T, Sterner O. Zopfiellamides A and B, antimicrobial pyrrolidinone derivatives from the marine fungus Zopfiella latipes. Tetrahedron 2002; 58: 7781-84.
Dulger B, Sen F, Gucin F. Russula delica Fr. Makrofungusunun antimikrobiyal aktivitesi. Turk J Biol. 1999; 23: 127-33.
Dulger B., Yayintas O.T. Gonuz A. Antimicrobial activity of some mosses from Turkey. Fitoterapia 2005; 76: 730-32.
Feldlaufer MF, Lusby WR, Knox DA, Shimanuki H. Isolation and identification of linoleic acid as an antimicrobial agent from the chalkbrood fungus, Ascosphaera apis. Apidologie 1993; 24: 89-94.
Glover D.E., Whittemore M.S., Bryant S.D. Methods and compositions for controlling biofouling using polyglycol fatty acid esters. Int Patent Application. 1997; WO97/11912.
Gunde-Cimerman N. Medicinal value of genus Pleurotus (Fr) P. Karst. (Agaricles S.R. Basidiomycetes). Int J Med Mushrooms. 1999; 1: 69-70.
Gunstone FD, Harwood JL, Dijkstra AJ. The lipid handbook with Cd-Rom. 3rd ed. Boca Raton: CRC Press, 2007.
Hidron AI, Edwards JR, Patel J. NHSN annual update: Antimicrobial-resistant pathogens associated with healthcare-associated infections: Annual summary of data reported to the National Healthcare Safety Network at the Centers for Disease Control and Prevention, 2006-2007. Infect Control Hosp Epidemiol. 2008; 29: 996-1011.
Hossain MA, Rahman A. Chemical composition of bioactive compounds by GC-MS screening and antifungal properties of crude extracts of cabbage samples. Asian J Biotechnol. 2011; 3: 68-76.
Huang CB, George B, Ebersole JL Antimicrobial activity of n-6, n-7 and n-9 fatty acids and their esters for oral microorganisms. Arch Oral Biol. 2011; 55: 555-60.
Imtiaj A, Lee TS. Screening of antibacterial and antifungal activities from Korean wild mushrooms. World J Agric Sci. 2007; 3: 316-21.
Kabara JJ, Swieczkowski DM, Conley AJ, Tuant JP. Fatty acids and derivatives as antimicrobial agents. Antimicrob Agents Chemother. 1972; 2: 23-28.
Knapp HR, Melly MA. Bactericidal effects of polyunsaturated fatty acids. J Infect Dis. 1986; 154: 84-94.
Liu S, Weibin R, Jing L, Hua X, Jingan W, Yubao G, Jingguo W. Biological control of phytopathogenic fungi by fatty acids. Mycopathologia 2008; 166: 93-102.
Mahida Y, Mohan JSS. Screening of plants for their potential antibacterial activity against Staphylococcus and Salmonella spp. Natural Product Radiance. 2007; 6: 301-05.
McGaw LJ, Jager AK, Van Staden J. Isolation of antibacterial fatty acids from Schotia brachypetala. Fitoter 2002; 73: 431-33.
Nalina T, Rahim ZHA. The crude aqueous extract of Piper betel L. and it's antibacterial effect towards Streptococcus mutans. Am J Biotechnol Biochem. 2007; 3: 10-15.
Narasimhan B, Mourya V, Dhake A. Design, synthesis, antibacterial, and QSAR studies of myristic acid derivatives. Bioorg Med Chem Lett. 2006; 16: 3023-29.
Nikaido H. Antibiotic resistance caused by Gram-negative multidrug efflux pumps. Clin Infect Dis. 1998; 27: 32-41.
Okeke IN, Laxmaninarayan R, Bhutta ZA, Duse AG, Jenkins P, O'Brien, TF, Pablos-Mendez A, Klugman KP. Antimicrobial resistance in developing countries. Part 1: Recent trends and current status. Lancet Infect Dis. 2005; 5: 481-93.
Ooi VEC. Medicinally important fungi. In: Science and cultivation of edible fungi. Van Griensven (ed.). Balkerna, Rotterdam, 2000, pp 41-51.
Quereshi S, Pandey AK, Sandhu SS. Evaluation of antibacterial activity of different Ganoderma lucidum extracts. People's J Sci Res. 2010; 3: 9-13.
Queck SY, Otto M. Staphylococcus epidermidis and other coagulase-negative Staphylococci. In: Staphylococcus: Molecular genetics. Lindsay JA (ed). UK, Caister Academic Press, 2008.
Risk M, Harrison P, Lewis J. Wood preserving composition. Int Patent Application. 1997; WO 97/34747.
Salyers A, Whitt D. Bacterial pathogenesis: A molecular approach. 2nd ed. Washington, ASM Press, 2002.
Sarac N, Ugur A. Antimicrobial activities and usage in folkloric medicine of some Lamiaceae species growing in Mugla, Turkey. Eur Asian J BioSci. 2007; 4: 28-37.
Savaroglu F, Filik Iscen C, Ilhan S. An evaluation of the antimicrobial activity of some Turkish mosses. J Med Plants Res. 2011; 5: 3286-92.
Seidel V, Taylor PW. In vitro activity of extracts and constituents of Pelagonium against rapidly growing mycobacteria. Int J Antimicrob Agents. 2004; 23: 613-19.
Skrivanova E, Marounek M, Benda V, Brezina P. Susceptibility of Escherichia coli, Salmonella sp. and Clostridium perfringens to organic acids and monolaurin. Veterinarni Medicina. 2006; 51: 81-88.
Sun CQ, O'Connor CJ, Roberton AM. Antibacterial actions of fatty acids and monoglycerides against Helicobacter pylori. FEMS Immunol Med Microbiol. 2003; 36: 9-17.
Tsuchida M, Morishlta Y. Antibacterial activity and bacterial degradation of linoleic acid hydroperoxide. Bifidobacteria Microflora. 1995; 14: 67-74.
Villegas MV, Quinn JP. An update on antibiotic-resistant Gram-negative bacteria. Infect Med. 2004; 21: 595-99.
Walters D, Raynor L, Mitchell A, Walker R, Walker K. Antifungal activities of four fatty acids against plant pathogenic fungi. Mycopathologia 2004; 157: 87-90.
Wasser SP, Weis AL. Medicinal properties of substances occurring in higher basidiomycete mushrooms: Current perspective. Int J Med Mushrooms. 1999a; 1: 31-62.
Wasser SP, Weis AL. Therapeutic properties of substances occurring in higher basidiomycete mushrooms: A modern perspective. Crit Rev Immunol. 1999b; 19: 65-96.
Zheng CJ, Yoo JS, Lee TG, Cho HY, Kim YH, Kim WG. Fatty acid synthesis is a target for antibacterial activity of unsaturated fatty acids. FEBS Lett. 2005; 579: 5157-62.
