Fennel Oil Fights Antifungal-Resistant Candida
Medical scientists have confirmed that fennel oil inhibits a number of strains of Candida that have grown resistant to antifungal medications.
In this article
Candida antifungal resistance growing
Conventional medicine typically prescribes antifungal medications to treat Candida overgrowth. Over the past few decades of this, many Candida strains have developed resistance to those antifungal medications.
The result is stronger and more resilient populations of Candia that can spread with fewer treatment options.
A number of essential oils have been shown in other research to fight Candida infections. Some of these have been shown to fight Candida better than some antifungal medications.
This is because plants are, like Candida fungi, alive. Because plants also fight fungal infections all around them, they are particularly good at fighting fungi. They are also good at producing compounds that are difficult for fungi to become resistant to.
And when microorganisms do become resistant to some plant compounds, the plants simply produce other compounds – or combinations of compounds – that deter the microorganisms. This is why plants can grow in soils and environments that are inundated with bacteria and fungi.
Can fennel oil really fight antifungal-resistant Candida?
Researchers from Egypt’s Fayoum University School of Medicine1 tested 34 different strains of Candida albicans that had developed a resistance to the antifungal medication fluconazole.
The Candida strains tested included:
• 19 different strains of Candida albicans
• 13 different strains of Candida glabrata
• 2 strains of Candida tropicalis
All of the strains had developed a resistance to the popular antifungal medication, fluconazole. Most of the strains also were significant biofilm producers. This means they could spread quickly and form significant regions of infection.
Along with fennel oil (Foeniculum vulgare), the researchers tested several other essential oils against the Candida species. These included:
• Chamomile oil (Anthemis nobilis)
• Jojoba oil (Simmondsia chinensis)
• Nigella oil (Nigella sativa)
• Fenugreek oil (Trigonella foenum-graecum)
• Cod-liver oil (Gadus morhua)
• Peppermint oil (Mentha piperita)
• Clove oil (Syzygium aromaticum)
• Ginger oil (Zingiber officinale)
Besides the fennel oil, the only oil that were also included in the 2016 study of essential oils against Candida was Clove oil.
The researchers found that all of the above oils, except for fennel and clove, were not able to inhibit the Candida species. Clove oil was nowhere near as successful as fennel.
The fennel oil inhibited all of the antifungal-resistant species of Candida tested:
“Our results revealed that fennel essential oil had high significant antifungal activities against all tested strains.”
The researchers also found the fennel oil significantly inhibited the growth of biofilms.
They found that concentrations of between 6.25 percent and 25 percent fennel oil could produce the effect of reducing biofilms by half on a single application.
Biofilm growth is one of the most dangerous elements of Candida infections.
Complexity helps explain fennel’s abilities
Fennel contains a number of antifungal compounds. This helps us understand why Candida has a harder time becoming resistant. These compounds include (in order of proportion):
• Anethole (41.4%)
• Limonene (24.7%)
• Fenchone (11.8%)
• Myrcene (5.2%)
• α-Pinene (4.1%)
• Estragole (2.8%)
• α-Phellandrene (2.2%)
• γ –Terpinene (1.5%)
• p-Cimene (1.1%)
• β-Pinene (0.5%)
• E-β-Ocimene (0.5%)
• α-Fenchene (0.6%)
• 1,8-Cineole (0.7%)
• Copaene (0.3%)
• α-Terpinolene (0.3%)
• Camphene (0.2%)
• Z-β-Ocimene (0.2%)
• Sabinene hydrate (0.1%)
As can be seen from this list, fennel oil is complicated. It is not just one compound like many pharmaceuticals. Single-compound pharmaceuticals are easy for Candida species to figure out how to resist.
Plant antifungals are most complicated. They contain combinations of medicinal compounds. These medicinal combinations, along with the introduction of newer and more precise antifungal properties for Candida to figure out.
Then even as they try to figure them out, the plants start producing different combinations to thwart any resistance.
Other research confirms fennel antifungal properties
We mentioned the 2016 study about multiple Candida-fighting oils. This research illustrated that fennel was one of the most antifungal essential oils, but so were Thyme, Clove, Pine and others. And surprisingly, the research also showed that aromatherapeutic application of some of these oils can also inhibit Candida.
In a 2009 study, researchers from Pakistan’s University of Agriculture2 tested fennel seed extracts against bacteria and fungi, and also found them to be significantly antibiotic and antifungal.
In a 2013 study, researchers tested fennel essential oils3 against bacteria and fungi. They found fennel oil inhibited the growth of fungi Aspergillus flavus and Candida albicans along with infective bacteria Bacillus cereus, and Staphylococcus aureus.
1. Bassyouni RH, Wali EI, KamelZ, Kassim MF. Fennel oil: A promising antifungal agent against biofilm forming fluconazole resistant Candida albicans causing vulvovaginal candidiasis. J Herb Med. 2019:15;Mar.
3. Roby MHH, Sarham MA, Selim KA, Kalel KI. Antioxidant and antimicrobial activities of essential oil and extracts of fennel (Foeniculum vulgare L.) and chamomile (Matricaria chamomilla L.) Ind Crops Prod. 2013:44;Jan., 437-445