Effect of Cinnamomum verum leaf essential oil on virulence factors of Candida species and determination of the in-vivo toxicity with Galleria mellonella model.

BACKGROUND: Essential oils (EO) extracted from Cinnamomum verum has been used as an antimicrobial agents for centuries. The effects of C. verum leaf oil against virulence of microorganisms is not well studied yet. OBJECTIVES: This study evaluates the effect of C. verum leaf oil against three virulence factors of Candida albicans, C. tropicalis and C. dubliniensis and its in-vivo toxicity. METHODS: Chemical composition of EO was determined using gas chromatography-mass spectrometry (GC-MS). Minimum inhibitory concentration (MIC) was determined using clinical and laboratory standards institute (CLSI) M27-A3 broth microdilution. Effect of EO on initial adhesion was quantified using XTT assay after allowing Candida cells to adhere to the polystyrene surface for 2 h. Biofilm formation of Candida in the presence of EO was quantified using XTT viability assay. Efficacy on reduction of germ tube formation was evaluated using standard protocol. Visualisation of biofilm formation and progression under the EO treatment were done using scanning electron microscope (SEM) and Time lapses microscope respectively. In-vivo toxicity of EO was determined using Galleria mellonella larvae. Chlorhexidine digluconate: positive control. RESULTS: Eugenol was the main compound of EO. MIC was 1.0 mg/mL. 50% reduction in initial adhesion was achieved by C. albicans, C. tropicalis and C. dubliniensis with 1.0, > 2.0 and 0.34 mg/mL respectively. 0.5 and 1.0 mg/mL significantly inhibit the germ tube formation. MBIC50 for forming biofilms were ≤ 0.35 mg/mL. 1.0 mg/mL prevent biofilm progression of Candida. SEM images exhibited cell wall damages, cellular shrinkages and decreased hyphal formation. No lethal effect was noted with in-vivo experiment model at any concentration tested. CONCLUSION: C. verum leaf oil acts against virulence factors of Candida and does not show any toxicity.

Efficacy of true cinnamon (Cinnamomum verum) leaf essential oil as a therapeutic alternative for Candida biofilm infections.

OBJECTIVES: The essential oil (EO) extracted from Cinnamomum verum leaves has been used as an antimicrobial agent for centuries. But its antifungal and antibiofilm efficacy is still not clearly studied. The objective of this research was to evaluate the in vitro antifungal and antibiofilm efficacy of C. verum leaf EO against C. albicans, C. tropicalis, and C. dubliniensis and the toxicity of EO using an in vitro model. MATERIALS AND METHODS: The effect of EO vapor was evaluated using a microatmosphere technique. CLSI microdilution assay was employed in determining the Minimum Inhibitory (MIC) and Fungicidal Concentrations (MFC). Killing time was determined using a standard protocol. The effect of EO on established biofilms was quantified and visualized using XTT and Scanning Electron Microscopy (SEM), respectively. Post-exposure intracellular changes were visualized using Transmission Electron Microscopy (TEM). The toxicological assessment was carried out with the Human Keratinocyte cell line. The chemical composition of EO was evaluated using Gas Chromatography-Mass Spectrometry (GC-MS). RESULTS: All test strains were susceptible to cinnamon oil vapor. EO exhibited MIC value 1.0 mg/ml and MFC value 2.0 mg/ml against test strains. The killing time of cinnamon oil was 6 hr. Minimum Biofilm Inhibitory Concentration (MBIC50) for established biofilms was <0.2 mg/ml for all test strains. SEM images exhibited cell wall damages, cellular shrinkages, and decreased hyphal formation of Candida. TEM indicated intracellular vacuolation, granulation, and cell wall damages. Cinnamon leaf oil caused no inhibition of HaCaT cells at any concentration tested. Eugenol was the abundant compound in cinnamon oil. CONCLUSION: C. verum EO is a potential alternative anti-Candida agent with minimal toxicity on the human host.

Purified bioactive compounds from Mentha spp. oils as a source of Candidosis treatment: A brief review / Compostos bioativos purificados de óleos de Mentha spp. como fonte de tratamento de candidose: Uma breve revisão

Medicinal plants have been the subject of many studies in an attempt to discovery alternative drugs, since they are sources of potentially bioactive compounds that may act in the maintenance of human health. The discovery of new antimicrobial substances or biocomponents derived from natural products has been important in the control of microorganisms, especially due to the increase of cases of resistance to conventional antimicrobials. In parallel, yeasts of the genus Candida are becoming a public health problem in the last decades due to the increase of infections denominated candidosis. Candida spp. has mechanisms of virulence, such as polymorphism and biofilm formation, that facilitate the development of the infection and difficult the treatment. In this sense, studies found in the literature with bioactive compounds from Mentha spp. essential oil, describe their antifungal action, especially from the isolated compounds as carvone, mentone, menthofuran and pulegone. In this sense, this review describes studies about antimicrobial activity of these compounds especially against yeasts of Candida species and some particularities of this genus such as virulence mechanisms once these themes are crucial for the development of new alternative drugs and/or antifungal agents that may act as adjuncts to conventional treatments against these microorganisms.(AU)

Plantas medicinais têm sido objeto de muitos estudos na tentativa de descobrir drogas alternativas, uma vez que são fontes de compostos potencialmente bioativos que podem atuar na manutenção da saúde humana. A descoberta de novas substâncias antimicrobianas ou biocomponentes derivadas de produtos naturais tem sido importante no controle de microrganismos, especialmente devido ao aumento de casos de resistência a antimicrobianos convencionais. Em paralelo, leveduras do gênero Candida vem se tornando um problema de saúde pública nas últimas décadas, devido ao aumento de infecções denominadas candidoses. Candida spp. possuem mecanismos de virulência, como polimorfismo e formação de biofilme, que facilitam o desenvolvimento da infecção e dificultam o tratamento. Nesse sentido, estudos na literatura com compostos bioativos do óleo essencial de Mentha spp. descrevem sua ação antifúngica, especialmente dos compostos isolados como carvona, mentona, mentofurano e pulegona. Sendo assim, esta revisão teve como objetivo abordar estudos sobre a atividade antimicrobiana destes compostos especialmente contra leveduras do gênero Candida e algumas particularidades desse gênero, tais como mecanismos de virulência, uma vez que esses temas se tornam cruciais para o desenvolvimento de novas drogas alternativas e/ou agentes antifúngicos que possam atuar como adjuvantes aos tratamentos convencionais contra esses microrganismos.(AU)

Purified bioactive compounds from Mentha spp. oils as a source of Candidosis treatment. A brief review.

Plantas medicinais têm sido objeto de muitos estudos na tentativa de descobrir drogas alternativas, uma vez que são fontes de compostos potencialmente bioativos que podem atuar na manutenção da saúde humana. A descoberta de novas substâncias antimicrobianas ou biocomponentes derivados de produtos naturais tem sido importante no controle de microrganismos, especialmente devido ao aumento de casos de resistência a antimicrobianos convencionais. Em paralelo, leveduras do gênero Candida vem se tornando um problema de saúde pública nas últimas décadas devido ao aumento de infecções denominadas candidoses. Candida spp. possuem mecanismos de virulência, como polimorfismo e formação de biofilme, que facilitam o desenvolvimento da infecção e dificultam o tratamento. Nesse sentido, estudos na literatura com compostos bioativos do óleo essencial de Mentha spp. descrevem sua ação antifúngica, especialmente dos compostos isolados como carvona, mentona, mentofurano e pulegona. Sendo assim, esta revisão teve como objetivo abordar estudos sobre a atividade antimicrobiana destes compostos especialmente contra leveduras do gênero Candida e algumas particularidades desse gênero tais como mecanismos de virulência uma vez que esses temas tornam-se cruciais para o desenvolvimento de novas drogas alternativas e/ou agentes antifúngicos que possam atuar como adjuvantes aos tratamentos convencionais contra esses microrganismos.