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- Light microphotographs of T. mentagrophytes LM02 mycelium growing on ASD with or without C. winterianus essential oil after 5 days of incubation at 28oC. Control experiment showing typical forms of the species (A, B). Changes in the development of hyphae induced by essential oil at 156 μg/mL (C, D). Bars: 100 μm.
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Trichophyton mentagrophytes is a fungus causative agent of dermatophytosis, affecting humans worldwide. This has driven the search for products for the treatment of these infections. Accordingly, the aim of this study was to investigate the antifungal activity of the Cymbopogon winterianus essential oil against T. mentagrophytes. The antifungal tes...
Contexts in source publication
Context 1
... addition of drugs was detectable (sterility control). Fun- gicide effect was stronger for T. mentagrophytes LM07, evidenced by lowest MFC value of 1250 μg/mL. MFC values were around eight times higher than MIC for all the tested strains. However, MFC for ketoconazole were about sixteen times higher than MIC values (1250-5000 μg/mL). It has long been recognized that some essential oils have antimicrobial properties which are possibly related to the function of these compounds in plants (Burt, 2004). Earlier, this essential oil was shown to exhibit an antimi- crobial effect against various pathogenic microorganisms to humans and plants, being useful for controlling mycotic diseases in large plantations, in addition to its activity as repellent and insecticide (Simic et al. , 2008; De-Blasi et al., 1990). Previous studies reported that citronellal and geraniol showed antifungal activity against Aspergillus niger, Fusarium oxysporum and Penicillium digitatum (Moleyar, Narasimham, 2004). However, scant infor- mation exists on the effects of C. winterianus essential oil against classical important fungi involved in human infections, including species of dermatophytes. The effects of C. winterianus essential oil on myce- lial growth are expressed as percentage of inhibition in dry mycelial weight of T. mentagrophytes LM02 and depicted in Figure 1. This study revealed that all concentrations of essential oil inhibited the development of mycelium. At each separate time point, all the concentrations tested differed (P<0.05) from results of 156 μg/mL. Also, at 156 μg/mL, the impediment of mycelial growth increased with the time of interaction between drug and fungal cells. With the other concentrations of essential oil, there was 100 % inhibition at all times analyzed. Dermatophytes produce hyphae which can penetrate the innermost layer of the skin and aggravate the damage in the host (Zurita, Hay, 1987). Therefore, some researchers are investigating essential oils’ potential for inhibiting mycelial growth of pathogenic fungi, due to their importance in mycosis development. The inhibition percentage of conidia germination of T. mentagrophytes LM 02 caused by different essential oil concentrations of C. winterianus are displayed in Fi- gure 2. In general, all concentrations of the essential oil exerted a strong inhibitory effect on conidia germination of the tested strain. As the essential oil concentration in- creased from 156 to 625 μg/mL, the inhibition percentage also increased, reaching values close to 100 %. Although these results are numerically relevant, the absence of germinated conidia in the culture, indicating total germi- nation inhibition, was observed only at 2500 μg/mL. By comparing these results, it is notable that the percentage of inhibition for 156 and 625, 2500 μg/mL was significantly different (P <0.05), supporting the idea that the increased concentration somehow enhances the inhibitory effect on germination. Finally, it was found that tween 80 did not affect conidia germination. Due to the importance of pro- per spore germination in dermatophytosis pathogenesis, the interference in the process caused by the essential oil proves relevant because this product was shown to be a promising tool for intervention of this infectious process. Figure 3 shows the results regarding the effects of the essential oil C. winterianus on the viability of T. mentagrophytes LM 02. After statistical analysis, it was observed that values differed (P<0.05) at each time of in- teraction analyzed. These observations can be seen by the logCFU/mL values of essential oil always being lower than those observed in the control experiment. The es- sential oil at 312 μg/mL was able to reduce fungal viabi- lity throughout the experimental period, reaching 100 % fungi viability inhibition from nine days of interaction. At 156 μg/mL this effect was also evident, although a lon- ger oil-fungi interaction period was needed (12 days of exposure). However, it is notable that at the highest concentrations, fungi failed to develop from the third day of interaction, making conditions completely impractical for growth. Tween 80 did not affect the fungal viability. Fungal mortality curves are sufficiently sensitive as a test designed to dynamically measure the capacity of a compound to act on the viability of a microorganism. The estimate of mortality of fungal structures can also be inferred for a given concentration of an antimicrobial compound, showing the speed of a fungicidal effect or the duration of a fungistatic effect (Burt, 2003; Cantón; Pemán, 1999). Thus, considering the results obtained, a fungicidal effect was confirmed for all concentrations of essential oil of C. winterianus , differing only in the time needed to exhibit this effect. Observations of T. mentagrophytes LM02 exa- mined under a light microscope at 400 x magnification after exposure to C. winterianus essential oil showed some morphological abnormalities (Figure 4). Essential oil induced similar alterations at all concentrations but increased markedly when the concentration of oil was increased. Although the form of T. mentagrophytes conidia did not change, their typical cluster was heavily damaged and they were shown to be highly scattered at all concen- trations of essential oil used. The vast majority of hyphae were often wider than normal hyphae, with great losses of pigmentation and presence of vacuoles widely distributed within them (Figure 4 C, D). Microscopic examination of the control mycelium (untreated cell) showed a regular cell structure with homogenous cytoplasm, abundant conidiation, long clear septate hyphae, with very rounded microconidia clustered on branched conidiophores. A few macroconidia were present as cigar shaped, thin walled and narrow attachments to hyphae (Figure 4 A, B). The results in this report directly impact disease pathogenesis, since dermatophytosis depends on normal morphogenesis capacity of fungi and their growth in infection locus. These modifications in fungal morphogenesis may be related to the interference of the essential oil with the enzymes responsible for synthesis or for maintenance of fungal cell wall, as previously cited by other researchers, impairing normal growth and cell morphogenesis (Debil- lerbeck et al . 2001; Gunji et al., 1983). Considering a possible interference of the essential oil on fungal cell wall, the oil was tested in the whole-cell sorbitol protection assay. In this test, sorbitol-protected cells can grow in the presence of inhibitor products of the fungal cell wall, while their growth is inhibited in the absence of sorbitol. This effect is detected by an increase in the MIC value obtained with sorbitol compared to MIC values without sorbitol (Svetaz et al ., 2007). MIC values in both experiments were identical, thus suggesting that C. winterianus essential oil does not act through the inhibition of fungal cell wall synthesis or assembly. An important characteristic of C. winterianus es- sential oil and its phytochemicals (e.g. mono-terpenes) is their hydrophobicity and consequently they can interact with fungal membrane, interfering in its integrity. This irreversible harm can be detected by measuring 260-nm- absorbing materials released to the medium, primarily representing nucleotides, of which uracil-containing compounds exhibited the strongest absorbance at different time intervals (2, 4 and 24 h). Amphotericin B was used as a positive control because it can complex with ergosterol in the fungal membranes, thereby compromising their barrier function to the point of causing leakage of cellular contents (Odds et al., 2003). The results showed that the essential oil and amphotericin B produced 100 % cell le- akage at 4h of interaction, as shown in Table II. Although the result obtained for MIC of the essential oil had been higher than the MIC of the positive control in 2 hours, both were statistically similar. These results confirm that the antifungal activity of C. winterianus essential oil is related to the interference with the integrity and functionality of T. mentagrophytes cell membrane. Due to the lipophilic character of essen- tial oils, they can partition fungal membranes into lipids rendering them more permeable, damaging their integrity and ultimately causing mycelial death (Sikkema et al., 1995; Cox et al., 2000; Burt et al., 2004). Therefore, the results found in this study may be considered relevant and promising. In conclusion, these results support the rational use of C. winterianus essential oil for the inhibition of der- matophyte growth. Furthermore, C. winterianus essential oil could lead to future developments involving its possible rational use for treatment of dermatophytosis. The authors would like to thank CNPq (Conselho Nacional de Desenvolvimento Científico e Tecnológico - Brazil) for grants and ...
Context 2
... (Burt, 2004). Earlier, this essential oil was shown to exhibit an antimi- crobial effect against various pathogenic microorganisms to humans and plants, being useful for controlling mycotic diseases in large plantations, in addition to its activity as repellent and insecticide (Simic et al. , 2008; De-Blasi et al., 1990). Previous studies reported that citronellal and geraniol showed antifungal activity against Aspergillus niger, Fusarium oxysporum and Penicillium digitatum (Moleyar, Narasimham, 2004). However, scant infor- mation exists on the effects of C. winterianus essential oil against classical important fungi involved in human infections, including species of dermatophytes. The effects of C. winterianus essential oil on myce- lial growth are expressed as percentage of inhibition in dry mycelial weight of T. mentagrophytes LM02 and depicted in Figure 1. This study revealed that all concentrations of essential oil inhibited the development of mycelium. At each separate time point, all the concentrations tested differed (P<0.05) from results of 156 μg/mL. Also, at 156 μg/mL, the impediment of mycelial growth increased with the time of interaction between drug and fungal cells. With the other concentrations of essential oil, there was 100 % inhibition at all times analyzed. Dermatophytes produce hyphae which can penetrate the innermost layer of the skin and aggravate the damage in the host (Zurita, Hay, 1987). Therefore, some researchers are investigating essential oils’ potential for inhibiting mycelial growth of pathogenic fungi, due to their importance in mycosis development. The inhibition percentage of conidia germination of T. mentagrophytes LM 02 caused by different essential oil concentrations of C. winterianus are displayed in Fi- gure 2. In general, all concentrations of the essential oil exerted a strong inhibitory effect on conidia germination of the tested strain. As the essential oil concentration in- creased from 156 to 625 μg/mL, the inhibition percentage also increased, reaching values close to 100 %. Although these results are numerically relevant, the absence of germinated conidia in the culture, indicating total germi- nation inhibition, was observed only at 2500 μg/mL. By comparing these results, it is notable that the percentage of inhibition for 156 and 625, 2500 μg/mL was significantly different (P <0.05), supporting the idea that the increased concentration somehow enhances the inhibitory effect on germination. Finally, it was found that tween 80 did not affect conidia germination. Due to the importance of pro- per spore germination in dermatophytosis pathogenesis, the interference in the process caused by the essential oil proves relevant because this product was shown to be a promising tool for intervention of this infectious process. Figure 3 shows the results regarding the effects of the essential oil C. winterianus on the viability of T. mentagrophytes LM 02. After statistical analysis, it was observed that values differed (P<0.05) at each time of in- teraction analyzed. These observations can be seen by the logCFU/mL values of essential oil always being lower than those observed in the control experiment. The es- sential oil at 312 μg/mL was able to reduce fungal viabi- lity throughout the experimental period, reaching 100 % fungi viability inhibition from nine days of interaction. At 156 μg/mL this effect was also evident, although a lon- ger oil-fungi interaction period was needed (12 days of exposure). However, it is notable that at the highest concentrations, fungi failed to develop from the third day of interaction, making conditions completely impractical for growth. Tween 80 did not affect the fungal viability. Fungal mortality curves are sufficiently sensitive as a test designed to dynamically measure the capacity of a compound to act on the viability of a microorganism. The estimate of mortality of fungal structures can also be inferred for a given concentration of an antimicrobial compound, showing the speed of a fungicidal effect or the duration of a fungistatic effect (Burt, 2003; Cantón; Pemán, 1999). Thus, considering the results obtained, a fungicidal effect was confirmed for all concentrations of essential oil of C. winterianus , differing only in the time needed to exhibit this effect. Observations of T. mentagrophytes LM02 exa- mined under a light microscope at 400 x magnification after exposure to C. winterianus essential oil showed some morphological abnormalities (Figure 4). Essential oil induced similar alterations at all concentrations but increased markedly when the concentration of oil was increased. Although the form of T. mentagrophytes conidia did not change, their typical cluster was heavily damaged and they were shown to be highly scattered at all concen- trations of essential oil used. The vast majority of hyphae were often wider than normal hyphae, with great losses of pigmentation and presence of vacuoles widely distributed within them (Figure 4 C, D). Microscopic examination of the control mycelium (untreated cell) showed a regular cell structure with homogenous cytoplasm, abundant conidiation, long clear septate hyphae, with very rounded microconidia clustered on branched conidiophores. A few macroconidia were present as cigar shaped, thin walled and narrow attachments to hyphae (Figure 4 A, B). The results in this report directly impact disease pathogenesis, since dermatophytosis depends on normal morphogenesis capacity of fungi and their growth in infection locus. These modifications in fungal morphogenesis may be related to the interference of the essential oil with the enzymes responsible for synthesis or for maintenance of fungal cell wall, as previously cited by other researchers, impairing normal growth and cell morphogenesis (Debil- lerbeck et al . 2001; Gunji et al., 1983). Considering a possible interference of the essential oil on fungal cell wall, the oil was tested in the whole-cell sorbitol protection assay. In this test, sorbitol-protected cells can grow in the presence of inhibitor products of the fungal cell wall, while their growth is inhibited in the absence of sorbitol. This effect is detected by an increase in the MIC value obtained with sorbitol compared to MIC values without sorbitol (Svetaz et al ., 2007). MIC values in both experiments were identical, thus suggesting that C. winterianus essential oil does not act through the inhibition of fungal cell wall synthesis or assembly. An important characteristic of C. winterianus es- sential oil and its phytochemicals (e.g. mono-terpenes) is their hydrophobicity and consequently they can interact with fungal membrane, interfering in its integrity. This irreversible harm can be detected by measuring 260-nm- absorbing materials released to the medium, primarily representing nucleotides, of which uracil-containing compounds exhibited the strongest absorbance at different time intervals (2, 4 and 24 h). Amphotericin B was used as a positive control because it can complex with ergosterol in the fungal membranes, thereby compromising their barrier function to the point of causing leakage of cellular contents (Odds et al., 2003). The results showed that the essential oil and amphotericin B produced 100 % cell le- akage at 4h of interaction, as shown in Table II. Although the result obtained for MIC of the essential oil had been higher than the MIC of the positive control in 2 hours, both were statistically similar. These results confirm that the antifungal activity of C. winterianus essential oil is related to the interference with the integrity and functionality of T. mentagrophytes cell membrane. Due to the lipophilic character of essen- tial oils, they can partition fungal membranes into lipids rendering them more permeable, damaging their integrity and ultimately causing mycelial death (Sikkema et al., 1995; Cox et al., 2000; Burt et al., 2004). Therefore, the results found in this study may be considered relevant and promising. In conclusion, these results support the rational use of C. winterianus essential oil for the inhibition of der- matophyte growth. Furthermore, C. winterianus essential oil could lead to future developments involving its possible rational use for treatment of dermatophytosis. The authors would like to thank CNPq (Conselho Nacional de Desenvolvimento Científico e Tecnológico - Brazil) for grants and ...
Context 3
... citronellal and geraniol showed antifungal activity against Aspergillus niger, Fusarium oxysporum and Penicillium digitatum (Moleyar, Narasimham, 2004). However, scant infor- mation exists on the effects of C. winterianus essential oil against classical important fungi involved in human infections, including species of dermatophytes. The effects of C. winterianus essential oil on myce- lial growth are expressed as percentage of inhibition in dry mycelial weight of T. mentagrophytes LM02 and depicted in Figure 1. This study revealed that all concentrations of essential oil inhibited the development of mycelium. At each separate time point, all the concentrations tested differed (P<0.05) from results of 156 μg/mL. Also, at 156 μg/mL, the impediment of mycelial growth increased with the time of interaction between drug and fungal cells. With the other concentrations of essential oil, there was 100 % inhibition at all times analyzed. Dermatophytes produce hyphae which can penetrate the innermost layer of the skin and aggravate the damage in the host (Zurita, Hay, 1987). Therefore, some researchers are investigating essential oils’ potential for inhibiting mycelial growth of pathogenic fungi, due to their importance in mycosis development. The inhibition percentage of conidia germination of T. mentagrophytes LM 02 caused by different essential oil concentrations of C. winterianus are displayed in Fi- gure 2. In general, all concentrations of the essential oil exerted a strong inhibitory effect on conidia germination of the tested strain. As the essential oil concentration in- creased from 156 to 625 μg/mL, the inhibition percentage also increased, reaching values close to 100 %. Although these results are numerically relevant, the absence of germinated conidia in the culture, indicating total germi- nation inhibition, was observed only at 2500 μg/mL. By comparing these results, it is notable that the percentage of inhibition for 156 and 625, 2500 μg/mL was significantly different (P <0.05), supporting the idea that the increased concentration somehow enhances the inhibitory effect on germination. Finally, it was found that tween 80 did not affect conidia germination. Due to the importance of pro- per spore germination in dermatophytosis pathogenesis, the interference in the process caused by the essential oil proves relevant because this product was shown to be a promising tool for intervention of this infectious process. Figure 3 shows the results regarding the effects of the essential oil C. winterianus on the viability of T. mentagrophytes LM 02. After statistical analysis, it was observed that values differed (P<0.05) at each time of in- teraction analyzed. These observations can be seen by the logCFU/mL values of essential oil always being lower than those observed in the control experiment. The es- sential oil at 312 μg/mL was able to reduce fungal viabi- lity throughout the experimental period, reaching 100 % fungi viability inhibition from nine days of interaction. At 156 μg/mL this effect was also evident, although a lon- ger oil-fungi interaction period was needed (12 days of exposure). However, it is notable that at the highest concentrations, fungi failed to develop from the third day of interaction, making conditions completely impractical for growth. Tween 80 did not affect the fungal viability. Fungal mortality curves are sufficiently sensitive as a test designed to dynamically measure the capacity of a compound to act on the viability of a microorganism. The estimate of mortality of fungal structures can also be inferred for a given concentration of an antimicrobial compound, showing the speed of a fungicidal effect or the duration of a fungistatic effect (Burt, 2003; Cantón; Pemán, 1999). Thus, considering the results obtained, a fungicidal effect was confirmed for all concentrations of essential oil of C. winterianus , differing only in the time needed to exhibit this effect. Observations of T. mentagrophytes LM02 exa- mined under a light microscope at 400 x magnification after exposure to C. winterianus essential oil showed some morphological abnormalities (Figure 4). Essential oil induced similar alterations at all concentrations but increased markedly when the concentration of oil was increased. Although the form of T. mentagrophytes conidia did not change, their typical cluster was heavily damaged and they were shown to be highly scattered at all concen- trations of essential oil used. The vast majority of hyphae were often wider than normal hyphae, with great losses of pigmentation and presence of vacuoles widely distributed within them (Figure 4 C, D). Microscopic examination of the control mycelium (untreated cell) showed a regular cell structure with homogenous cytoplasm, abundant conidiation, long clear septate hyphae, with very rounded microconidia clustered on branched conidiophores. A few macroconidia were present as cigar shaped, thin walled and narrow attachments to hyphae (Figure 4 A, B). The results in this report directly impact disease pathogenesis, since dermatophytosis depends on normal morphogenesis capacity of fungi and their growth in infection locus. These modifications in fungal morphogenesis may be related to the interference of the essential oil with the enzymes responsible for synthesis or for maintenance of fungal cell wall, as previously cited by other researchers, impairing normal growth and cell morphogenesis (Debil- lerbeck et al . 2001; Gunji et al., 1983). Considering a possible interference of the essential oil on fungal cell wall, the oil was tested in the whole-cell sorbitol protection assay. In this test, sorbitol-protected cells can grow in the presence of inhibitor products of the fungal cell wall, while their growth is inhibited in the absence of sorbitol. This effect is detected by an increase in the MIC value obtained with sorbitol compared to MIC values without sorbitol (Svetaz et al ., 2007). MIC values in both experiments were identical, thus suggesting that C. winterianus essential oil does not act through the inhibition of fungal cell wall synthesis or assembly. An important characteristic of C. winterianus es- sential oil and its phytochemicals (e.g. mono-terpenes) is their hydrophobicity and consequently they can interact with fungal membrane, interfering in its integrity. This irreversible harm can be detected by measuring 260-nm- absorbing materials released to the medium, primarily representing nucleotides, of which uracil-containing compounds exhibited the strongest absorbance at different time intervals (2, 4 and 24 h). Amphotericin B was used as a positive control because it can complex with ergosterol in the fungal membranes, thereby compromising their barrier function to the point of causing leakage of cellular contents (Odds et al., 2003). The results showed that the essential oil and amphotericin B produced 100 % cell le- akage at 4h of interaction, as shown in Table II. Although the result obtained for MIC of the essential oil had been higher than the MIC of the positive control in 2 hours, both were statistically similar. These results confirm that the antifungal activity of C. winterianus essential oil is related to the interference with the integrity and functionality of T. mentagrophytes cell membrane. Due to the lipophilic character of essen- tial oils, they can partition fungal membranes into lipids rendering them more permeable, damaging their integrity and ultimately causing mycelial death (Sikkema et al., 1995; Cox et al., 2000; Burt et al., 2004). Therefore, the results found in this study may be considered relevant and promising. In conclusion, these results support the rational use of C. winterianus essential oil for the inhibition of der- matophyte growth. Furthermore, C. winterianus essential oil could lead to future developments involving its possible rational use for treatment of dermatophytosis. The authors would like to thank CNPq (Conselho Nacional de Desenvolvimento Científico e Tecnológico - Brazil) for grants and ...
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Citations
... nsitivity to the C. eugenioides extract. Z. rhoifolium presented a superior potential against L. amazonensis. Given these results, the current study has noted that the antimicrobial activities of the deliberated species were promising, yet further studies ensuing a notably greater specificity, together with cytotoxicity tests, are required (Moura-.Pereira et al. (2011) verified the antifungal activities of the Cymbopogon winterianus Jowitt ex Bor essential oil, ...
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... In addition, researchers are interested in precursors to be used in new medicines for human and animal use with higher efficacy and safety. Many essential oils demonstrate strong pharmacological properties as antiinflammatory, antimicrobial, anticytotoxic, antioxidant, antifungal, antinociceptive, antipyretic, healing and antileishmanial activities (Bakkali et al., 2008;Cardile et al., 2009;Ribeiro et al., 2010;Pereira et al., 2011;Sousa, 2012;Ract et al., 2015;Miranda et al., 2016;Damasceno et al., 2017;Pereira et al., 2017;Kauffmann et al., 2019). ...
Essential oils are an important natural source of pesticides and can be suitable used in ectoparasite control. The goal of this paper was to investigate the chemical composition of the volatile oils obtained from leaves and stems of Philodendron meridionale Buturi & Sakur by gas chromatography/mass spectrometry and to evaluate their insecticidal effect against Ctenocephalides felis Bouché adult insects and their cytotoxicity on human Jurkat leukemic T-cells by 3-(4,5-dimethylthiazol-2-yl)-2,5diphenyltetrazoluim bromide (MTT) reduction method. The main compound was ent-kaur-16-ene at concentrations of 20.78 and 22.46% for volatile oils from leaves and stems, respectively. These volatile oils provided insecticidal effect against C. felis with an average knockdown time of 9.61 and 7.35 min for fumigant test performed with the leaves and stems samples, respectively. Considering the topical application, these P. meridionale volatile oils extracted from leaves and stems demonstrated average knockdown values of 14.70 and 20.0 min, respectively. A very low cytotoxic effect of 9.48 and 11.32% was observed for P. meridionale volatile oils from leaves and stems even at the highest tested concentration of 400 μg.mL-1, respectively. Therefore, it is possible to propose a biological selectivity to the volatile oils under study, which guarantees, at the same time, effect against this insect with no evident damage to human biological system.
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... Mycobacterium tuberculosis H 37 Ra cell treated with Mutellina purpurea L. essential oil components showed that the mono-and sesquiterpenes penetrated/destabilized the complex mycobacterial cell wall and decreased its viability [44]. Essential oils isolated from Cymbopogon Winterianus Jowitt Ex Bor showed morphological changes in the common dermatophytes Trichophyton rubrum responsible for causing mycosis showed folds in their colony, cream colour appearance and slightly darker than the control [45]. The antifungal action of essential oil isolated from Dill (Anethum graveolens L.) showed its activity through disruption of permeability barrier of the plasma membrane and from the mitochondrial dysfunction-induced ROS accumulation in it [46]. ...
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... The effect of the surfactants was also assessed on the germination of dermatophyte microconidia according to the methodology previously described [28] with some adaptations. Assays were carried out using 96-well flat-bottom microtiter plates (Global Plast, Global Trade Technology, Brazil). ...
Background
Amino acid based surfactants constitute an important class of surface active biomolecules showing remarkable biocompatible properties. Antimicrobial activity is one of the most remarkable biological properties of this kind of surfactants, which have been widely studied against a broad spectrum of microorganisms. However, the antifungal activity of this kind of compound has been less well investigated. The aim of this work is the study of the antifungal activity of two novel argininebased surfactants (Nα-benzoyl-arginine decylamide, Bz-Arg-NHC10 and Nα-benzoyl-arginine dodecylamide, Bz-Arg-NHC12), obtained by an enzymatic strategy, against phytopathogenic filamentous fungi and dermatophyte strains.
Methods
Four phytopathogenic fungi (Fusarium oxysporum, Fusarium solani, Colletotrichum gloeosporioides and Colletotrichum lindemuthianum) and two human pathogenic fungi (dermatophytes Trichophyton rubrum and Trichophyton mentagrophytes) were tested. Inhibition of vegetative growth and conidia germination was investigated for the phytopathogenic fungi. In order to elucidate the possible mechanism of biocide action, membrane integrity, as well as the production of reactive oxygen species (ROS) were evaluated. Additionally, the inhibition of germination of dermatophyte microconidia due to both arginine-based surfactants was studied. Minimum inhibitory concentration, as well as the concentration that inhibits 50% of germination were determined for both compounds and both fungal strains.
Results
For the vegetative growth of phytopathogenic fungi, the most potent arginine-based compound was Bz-Arg-NHC10. All the tested compounds interfered with the conidia development of the studied species. Investigation of the possible mechanism of toxicity towards phytopathogenic fungi indicated direct damage of the plasma membrane and production of ROS. For the two strains of dermatophyte fungi tested, all the proved compounds showed similar fungistatic efficacy.
Conclusion
: Bz-Arg-NHC10 and Bz-Arg-NHC12 were demonstrated to have broad biocidal ability against the proliferative vegetative form and the asexual reproductive conidia. Results suggest that both membrane permeabilization and induction of oxidative stress are part of the antifungal mechanisms involved in the interruption of normal conidia development by Bz-Arg-NHCn, leading to cell death.
... The dermatophytic infections affect approximately 40% of the world's population. Among all mycotic skin infections dermatophytic infections represent 30% [1][2][3][4][5]. Predominance of dermatophyte species in Northeastern part of India has also been reported by many authors [6][7][8][9]. ...
... The conventional therapy for sporotrichosis includes the use of antifungal agents such as potassium iodide, itraconazole, ketoconazole, amphotericin B and terbinafine, among others, as well as the adoption of local thermal therapy and the surgical excision of the lesion Gremião et al., 2009;Honse et al., 2010;Pereira et al., 2011;Gremião et al., 2011;Reis et al., 2012). The preferred antifungal therapy for cat and dogs with sporotrichosis has been itraconazole administered daily orally at the dose of 10 to 40 mg kg -1 for a minimum period of three months and up to one year with no apparent adverse effects (Madrid et al., 2010;Larsson, 2011;Rossi et al., 2013). ...
Cases of sporotrichosis in humans and animals without satisfactory clinical response have increased, a warning sign of strains resistant to conventional antifungal agents. The urgent search for alternative therapies was an incentive for research on medicinal plants with anti-Sporothrix spp. properties. A bibliographic survey was performed based on scientific papers about in vitro and in vivo antifungal activity of essential oils and extracts of plants in differents solvents against the fungal of the Sporothrix schenckii complex. The study methodology consisted of a literature review in Google Scholar, Science Direct, Pubmed, Bireme and Springer link with papers from 1986 to 2015. We found 141 species of plants that were investigated, of which 100 species were concentrated in 39 botanical families that had confirmed anti-Sporothrix activity. Combretaceae, Asteraceae and Lamiaceae represented the botanical families with the greatest number of plants species with antifungal potential, using different methodologies. However, there are few studies with medicinal plants in experimental infection in animals that prove their activity in the treatment of sporotrichosis. It reinforces the need for further research related to standardization of in vitro methodologies and in vivo studies related to safety and to toxicity potential of these plants with anti-Sporothrix spp. activity. © 2016, Faculdade de Ciencias Farmaceuticas (Biblioteca). All rights reserved.
... Dentro de las varias clases de compuestos aislados de plantas con propiedades antimicrobianas, los aceites esenciales son uno de los grupos de compuestos naturales más prometedores, reconocidos por presentar una actividad contra un gran número de microorganismos, incluyendo especies resistentes a los antibióticos y antifúngicos (Lima et al., 2006;Castro y Lima, 2010;Saad et al., 2010;Pereira et al., 2011). ...
... and Aspergillus spp. [18,[19][20][21][22][23][24][25][26][27]. However, studies on the antifungal activity of essential oils and their components against species of Rhizopus, the main genus responsible for causing the majority of mucormycosis, are scarce. ...
... These results suggested that the substances evaluated inhibited normal mycelial development of R. oryzae at all concentrations tested. These results corroborate the data obtained by some researchers who have investigated the antifungal potential of essential oils in inhibiting the mycelial growth of pathogenic and non-pathogenic fungi [24,34]. The essential oils of two varieties of thyme, Thymus eriocalyx and Thymus x-porlock, inhibited the mycelial growth of Aspergillus parasiticus [34]. ...
... The essential oils of two varieties of thyme, Thymus eriocalyx and Thymus x-porlock, inhibited the mycelial growth of Aspergillus parasiticus [34]. Recently, our research group showed that the essential oil of C. winterianus inhibited the mycelial development of Trichophyton mentagrophytes [24]. The results reported to date can be considered of great relevance, due to the importance of mycelial growth in the development of mucormycosis, since the fungi of the order Mucorales, including the species of Rhizopus, the main causative agent of these infections, are characterized by an erect aerial mycelium, described as fibers or "cotton candy", which grow well and rapidly [7]. ...
Mucormycoses are emerging infections that have high rates of morbidity and mortality. They show high resistance to antifungal agents, and there is a limited therapeutic arsenal currently available, therefore, there is a great need to give priority to testing therapeutic agents for the treatment of mucormycosis. Along this line, the use of essential oils and phytoconstituents has been emphasized as a new therapeutic approach. The objective of this work was to investigate the antifungal activity of the essential oil (EO) of Thymus vulgaris, and its constituents thymol and p-cymene against Rhizopus oryzae, through microbiological screening, determination of minimal inhibitory concentration (MICs) and minimal fungicidal concentration (MFCs), effects on mycelial growth and germination of sporangiospores and interaction with ergosterol. The MIC of EO and thymol varied 128-512 µg/mL, but the MFC of EO and thymol varied 512-1024 µg/mL and 128-1024 µg/mL, respectively. The results also showed that EO and thymol significantly inhibited mycelial development and germination of sporangiospores. Investigation of the mechanism of antifungal action showed that EO and thymol interact with ergosterol. These data indicate that EO of T. vulgaris and thymol possess strong antifungal activity, which can be related to their interaction with ergosterol, supporting the possible use of these products in the treatment of mucormycosis.
... Dentro de las varias clases de compuestos aislados de plantas con propiedades antimicrobianas, los aceites esenciales son uno de los grupos de compuestos naturales más prometedores, reconocidos por presentar una actividad contra un gran número de microorganismos, incluyendo especies resistentes a los antibióticos y antifúngicos (Lima et al., 2006;Castro y Lima, 2010;Saad et al., 2010;Pereira et al., 2011). ...
Candidiasis is an opportunistic fungal infection caused by Candida yeasts. In Brazil, C. tropicalis is the second most frequently isolated microorganism after C. albicans. The arising of strains resistant to conventional antifungal agents has increased the search for new alternatives from natural products, especially essential oils. This research investigated essential oil activity against strains of C. tropicalis by disk diffusion method. The minimum inhibitory concentration (MIC) and minimum fungicidal concentration (MFC) were also determinate. In the disk diffusion, the essential oils of Cinnamomum zeylanicum, Eugenia caryophyllata and Origanum vulgare had the highest inhibition zones values. MIC and MFC values of E. caryophyllata essential oil were 512 and 1024 μg/mL, respectively. MIC and MFC amphotericin B values were identical (2 μg/mL). Therefore, it was concluded that E. caryophyllata essential oil has strong antifungal activity and may be subject to further studies.
