Synergistic Nanoparticle–Essential Oil Combinations Show Promising Antifungal Activity Original paper
Researched by:
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Karen Pendergrass
ID
Karen Pendergrass
Karen Pendergrass is a microbiome researcher specializing in microbiome-targeted interventions (MBTIs). She systematically analyzes scientific literature to identify microbial patterns, develop hypotheses, and validate interventions. As the founder of the Microbiome Signatures Database, she bridges microbiome research with clinical practice. In 2012, based on her own investigative research, she became the first documented case of FMT for Celiac Disease—four years before the first published case study.
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Microbes
Microbes
Microbes, short for microorganisms, are tiny living organisms that are ubiquitous in the environment, including on and inside the human body. They play a crucial role in human health and disease, functioning within complex ecosystems in various parts of the body, such as the skin, mouth, gut, and respiratory tract. The human microbiome, which is […]
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Microsporum canis (M. canis)
Microsporum canis (M. canis)
OverviewMicrosporum canis (M. canis) is a zoophilic dermatophyte common in cats and dogs, responsible for 90% of feline dermatophytoses worldwide.[1][2] It has significant zoonotic potential, transmitting to humans through fomites or direct animal contact, causing severe superficial mycosis. M. canis is considered anthropo-zoophilic and can infect pediatric or immunocompromised patients, causing severe inflammatory responses such […]
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Karen Pendergrass
Researched by:
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Karen Pendergrass
ID
Karen Pendergrass
Microbiome Signatures identifies and validates condition-specific microbiome shifts and interventions to accelerate clinical translation. Our multidisciplinary team supports clinicians, researchers, and innovators in turning microbiome science into actionable medicine.
Karen Pendergrass
What was studied?
This study evaluated the antidermatophytic activity of eight novel metallic nanoparticle (NP) compounds, both as individual agents and in synergistic combinations with essential oils (EOs), against five dermatophyte species. The nanoparticles—Ag₀.₄₉Cr₂.₅₁O₄, Ag₀.₉₉Fe₁.₀₁O₃, CoLa₀.₀₁₉Fe₁.₉₈₁O₄, Co₀.₉₉Fe₁.₉₉O₄, Ag₀.₉₉Cr₁.₀₁O₂, Ca₀.₉₉Fe₁.₉₉O₄, CoBi₀.₀₁₉Fe₁.₉₈₁O₄, and Cu₀.₉₉Fe₁.₉₉O₄—were synthesized via flash auto-combustion. The antifungal efficacy was further assessed by combining the four active nanoparticle compounds with five essential oils (cinnamon, clove, lemongrass, tea tree, and thyme), aiming to identify synergistic interactions capable of overcoming rising antifungal resistance in dermatophytes.
Who was studied?
The dermatophytic species evaluated in vitro included Microsporum canis, Trichophyton tonsurans, T. violaceum, T. verrucosum, and Epidermophyton floccosum, all of which were sourced from the Dermatology Department at Cairo University. Morphological and microscopic identification methods confirmed the species. The study utilized standard antifungal susceptibility assays (Kirby-Bauer disc diffusion, MIC determination via broth microdilution, and FICI analysis) to assess inhibitory efficacy.
Most important findings
Among the eight synthesized NP compounds, only four—Ag₀.₄₉Cr₂.₅₁O₄, Ag₀.₉₉Fe₁.₀₁O₃, CoLa₀.₀₁₉Fe₁.₉₈₁O₄, and Co₀.₉₉Fe₁.₉₉O₄—exhibited measurable antidermatophytic activity. Ag₀.₉₉Fe₁.₀₁O₃ demonstrated the strongest activity, particularly against M. canis, showing a 19 mm inhibition zone and a 211% relative activity compared to terbinafine. The combination of Ag₀.₉₉Fe₁.₀₁O₃ with cinnamon yielded the most potent synergy, resulting in a 47 mm inhibition zone and a fractional inhibitory concentration index (FICI) ≤ 0.5 across all species tested. The lowest MIC values were observed for Ag₀.₉₉Fe₁.₀₁O₃ with cinnamon (6.25 µg/mL / 2 µL/mL), confirming strong synergy. Several other combinations involving Ag₀.₉₉Fe₁.₀₁O₃ (with clove and lemongrass) also showed synergistic effects. In contrast, combinations with thyme and tea tree oils often showed antagonistic or indifferent effects.
Synergistic combinations with FICI ≤ 0.5 (synergistic effect):
| Combination | M. canis | T. tonsurans | T. violaceum | T. verrucosum | E. floccosum |
|---|---|---|---|---|---|
| Ag₀.₉₉Fe₁.₀₁O₃ + Cinnamon | 0.375 | 0.5 | 0.375 | 0.3125 | 0.375 |
| Ag₀.₉₉Fe₁.₀₁O₃ + Clove | 0.25 | 0.375 | 0.375 | 0.5 | 0.5 |
| Ag₀.₉₉Fe₁.₀₁O₃ + Lemongrass | 0.375 | 0.5 | 0.5 | 0.375 | 0.375 |
Combinations involving other NPs and EOs largely yielded indifferent or antagonistic interactions.
Key implications
The study provides compelling evidence for the synergistic antifungal potential of metallic nanoparticles, particularly Ag₀.₉₉Fe₁.₀₁O₃, when combined with specific essential oils such as cinnamon, clove, and lemongrass. These combinations not only surpassed the antifungal efficacy of standard treatments like terbinafine but also demonstrated lower minimum inhibitory concentrations and favorable FICI values. This indicates a promising alternative strategy to combat the rising issue of antifungal resistance in dermatophytes, especially M. canis, which is increasingly resistant to first-line antifungals. However, the study emphasizes the need for further toxicological and mechanistic investigations before clinical translation.