Sclareolide as Antifungal Strategy Against <i>Cryptococcus neoformans</i>: Unveiling Its Mechanisms of Action
Cryptococcal infection commonly begins as an opportunistic infection in humans, however, this can escalate to a systemic or life-threatening form in immunocompromised individuals. Here, we aim to identify novel antifungal molecules from plants resources. Sclareolide, a phytochemical classified as a...
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2024-11-01
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| author | Arumugam Ganeshkumar Patricia Michelle Nagai de Lima Jebiti Haribabu Bruno Montanari Borges Nycolas Willian Preite Flavio Vieira Loures Arunachalam Arulraj Juliana Campos Junqueira |
| author_facet | Arumugam Ganeshkumar Patricia Michelle Nagai de Lima Jebiti Haribabu Bruno Montanari Borges Nycolas Willian Preite Flavio Vieira Loures Arunachalam Arulraj Juliana Campos Junqueira |
| author_sort | Arumugam Ganeshkumar |
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| description | Cryptococcal infection commonly begins as an opportunistic infection in humans, however, this can escalate to a systemic or life-threatening form in immunocompromised individuals. Here, we aim to identify novel antifungal molecules from plants resources. Sclareolide, a phytochemical classified as a sesquiterpene lactone, was assessed against <i>Cryptococcus neoformans</i> H99. Sclareolide exhibited promising antifungal properties with a minimum inhibitory concentration (MIC) of 16 µg/mL. Additionally, the <i>C. neoformans</i> growth rate was significantly affected by sclareolide treatment in a concentration-dependent manner, as observed through a time killing assay, with a significant reduction at MIC × 8 compared to the control by 48 h. To elucidate the underlying mechanisms of sclareolide antifungal activity, fluorescence-based methods were employed. Propidium iodide (PI) accumulation assay indicated a reduction in C. <i>neoformans</i> membrane integrity, with values as low as 6.62 ± 0.18% after treatment. Moreover, sclareolide at MIC × 4 and MIC × 8 significantly increased the production of reactive oxygen species (ROS) and reduced the mitochondrial membrane potential (MMP), suggesting oxidative stress and mitochondrial dysfunction in <i>C. neoformans</i>. Sclareolide did not induce caspase-dependent apoptosis, suggesting a non-apoptotic mechanism. Further, a checkerboard experiment was performed to assess potential synergistic interaction with Amphotericin B, however, no synergism was observed. Moving on, sclareolide at 128 µg/mL did not exhibit toxicity in <i>Galleria mellonella,</i> further supporting its potential as a safe antifungal agent. These findings suggest that the antifungal activity of sclareolide against <i>C. neoformans</i> is mediated by oxidative stress. Further in vivo and pharmacokinetic studies are recommended to explore the potential of sclareolide as a prototype for the development of novel anti-cryptococcal therapies. |
| format | Article |
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| institution | OA Journals |
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| publishDate | 2024-11-01 |
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| spelling | doaj-art-75139e6b359c47fd8cb5965d30276adc2025-08-20T02:05:06ZengMDPI AGMicroorganisms2076-26072024-11-011211232410.3390/microorganisms12112324Sclareolide as Antifungal Strategy Against <i>Cryptococcus neoformans</i>: Unveiling Its Mechanisms of ActionArumugam Ganeshkumar0Patricia Michelle Nagai de Lima1Jebiti Haribabu2Bruno Montanari Borges3Nycolas Willian Preite4Flavio Vieira Loures5Arunachalam Arulraj6Juliana Campos Junqueira7Department of Biosciences and Oral Diagnosis, Institute of Science and Technology, Sao Paulo State University (UNESP), Sao Jose dos Campos, São Paulo 12245-000, BrazilDepartment of Biosciences and Oral Diagnosis, Institute of Science and Technology, Sao Paulo State University (UNESP), Sao Jose dos Campos, São Paulo 12245-000, BrazilFaculty of Medicine, University of Atacama, Los Carreras 1579, Copiapo 1532502, ChileInstitute of Science and Technology, Federal University of Sao Paulo (UNIFESP), Sao Jose dos Campos, Sao Paulo 12231-280, BrazilInstitute of Science and Technology, Federal University of Sao Paulo (UNIFESP), Sao Jose dos Campos, Sao Paulo 12231-280, BrazilInstitute of Science and Technology, Federal University of Sao Paulo (UNIFESP), Sao Jose dos Campos, Sao Paulo 12231-280, BrazilDepartamento de Electricidad, Facultad de Ingeniería, Universidad Tecnológica Metropolitana (UTEM), Av. José Pedro Alessandri 1242, Ñuñoa, Santiago 7800002, ChileDepartment of Biosciences and Oral Diagnosis, Institute of Science and Technology, Sao Paulo State University (UNESP), Sao Jose dos Campos, São Paulo 12245-000, BrazilCryptococcal infection commonly begins as an opportunistic infection in humans, however, this can escalate to a systemic or life-threatening form in immunocompromised individuals. Here, we aim to identify novel antifungal molecules from plants resources. Sclareolide, a phytochemical classified as a sesquiterpene lactone, was assessed against <i>Cryptococcus neoformans</i> H99. Sclareolide exhibited promising antifungal properties with a minimum inhibitory concentration (MIC) of 16 µg/mL. Additionally, the <i>C. neoformans</i> growth rate was significantly affected by sclareolide treatment in a concentration-dependent manner, as observed through a time killing assay, with a significant reduction at MIC × 8 compared to the control by 48 h. To elucidate the underlying mechanisms of sclareolide antifungal activity, fluorescence-based methods were employed. Propidium iodide (PI) accumulation assay indicated a reduction in C. <i>neoformans</i> membrane integrity, with values as low as 6.62 ± 0.18% after treatment. Moreover, sclareolide at MIC × 4 and MIC × 8 significantly increased the production of reactive oxygen species (ROS) and reduced the mitochondrial membrane potential (MMP), suggesting oxidative stress and mitochondrial dysfunction in <i>C. neoformans</i>. Sclareolide did not induce caspase-dependent apoptosis, suggesting a non-apoptotic mechanism. Further, a checkerboard experiment was performed to assess potential synergistic interaction with Amphotericin B, however, no synergism was observed. Moving on, sclareolide at 128 µg/mL did not exhibit toxicity in <i>Galleria mellonella,</i> further supporting its potential as a safe antifungal agent. These findings suggest that the antifungal activity of sclareolide against <i>C. neoformans</i> is mediated by oxidative stress. Further in vivo and pharmacokinetic studies are recommended to explore the potential of sclareolide as a prototype for the development of novel anti-cryptococcal therapies.https://www.mdpi.com/2076-2607/12/11/2324<i>Cryptococcus</i>phytochemicalssclareolideantifungalsROS and MMP |
| spellingShingle | Arumugam Ganeshkumar Patricia Michelle Nagai de Lima Jebiti Haribabu Bruno Montanari Borges Nycolas Willian Preite Flavio Vieira Loures Arunachalam Arulraj Juliana Campos Junqueira Sclareolide as Antifungal Strategy Against <i>Cryptococcus neoformans</i>: Unveiling Its Mechanisms of Action Microorganisms <i>Cryptococcus</i> phytochemicals sclareolide antifungals ROS and MMP |
| title | Sclareolide as Antifungal Strategy Against <i>Cryptococcus neoformans</i>: Unveiling Its Mechanisms of Action |
| title_full | Sclareolide as Antifungal Strategy Against <i>Cryptococcus neoformans</i>: Unveiling Its Mechanisms of Action |
| title_fullStr | Sclareolide as Antifungal Strategy Against <i>Cryptococcus neoformans</i>: Unveiling Its Mechanisms of Action |
| title_full_unstemmed | Sclareolide as Antifungal Strategy Against <i>Cryptococcus neoformans</i>: Unveiling Its Mechanisms of Action |
| title_short | Sclareolide as Antifungal Strategy Against <i>Cryptococcus neoformans</i>: Unveiling Its Mechanisms of Action |
| title_sort | sclareolide as antifungal strategy against i cryptococcus neoformans i unveiling its mechanisms of action |
| topic | <i>Cryptococcus</i> phytochemicals sclareolide antifungals ROS and MMP |
| url | https://www.mdpi.com/2076-2607/12/11/2324 |
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