Citronella and propolis emerge as antifungal, antibacterial and antioxidant oral and skin care solutions

26 Sep 2024 --- A recent study in Cosmetics examines the antifungal, antibacterial and antioxidant potential of citronella oil (Cymbopogon nardus) in combination with an active ingredient from propolis, caffeic acid phenethyl ester (CAPE). The research could potentially impact personal care products like mouthwash, antifungal ointments or skin treatments. 

Researchers discovered that although both CAPE and citronella oil are well-known for their antimicrobial qualities, their combined use significantly increased their antifungal efficacy, especially against Candida species.

They believe the organic substances could be added to personal care products that treat fungal infections. With increasing resistance to conventional antifungal treatments, the researchers suggest natural substitutes such as CAPE and citronella oil may provide a useful remedy.

Citronella oil and CAPE combine to create a potent antifungal solution targeting Candida species.Antioxidant and antifungal action

The compounds’ antioxidant potential were evaluated using the Ferric Reducing Antioxidant Power (FRAP) test and the DPPH test. According to the DPPH results, isolated CAPE had higher antioxidant activity at 13 ± 3 mg/mL, and the combination of citronella oil and CAPE had a moderate antioxidant effect with an IC50 value of 32 ± 9 mg/mL. 

Despite the lower antioxidant capacity, the compounds’ antifungal action was notable — minimum inhibitory concentration and minimum fungicidal concentration values of 0.5 mg/mL for citronella and 0.031 mg/mL for CAPE.

The study also tested the compounds’ ability to fight biofilm formation, a key factor in treating fungal infections. When applied for both short and extended periods (one minute and six hours), researchers saw citronella and CAPE successfully inhibit fungal biofilms. 

Natural solutions in demand

In addition to its antifungal properties, the research found that neither citronella oil nor CAPE caused significant irritation based on the hen’s egg chorioallantoic membrane test (HET-CAM), a widely accepted alternative to animal testing. The test suggests that the compounds could be safely incorporated into personal care formulations. 

The combination of citronella oil and CAPE, proven to eliminate biofilms and inhibit fungal growth, may be further developed for oral and skin care.

Personal Care Insights recently talked to ApiotiX about how it uses propolis as a “safe, effective” retinol alternative in anti-aging cosmetic products. Citronella oil is also used by Kao in its Bioré Guard Mos Block Lotion to protect the skin from mosquitoes.

By Venya Patel