Gallic acid (GA; 3,4,5-trihydroxy benzoic acid) is a natural polyphenol ubiquitously present in fruits, vegetables, legumes, and herbal medicines.
8 Previous studies have reported that GA and its derivatives possess a variety of biological properties, such as antioxidative, antiviral, anticancer, and anti-inflammatory activities.
9 For example, GA can bind and quench reactive oxygen species (ROS) with high affinity, thereby ameliorating oxidative stress-associated tissue damage in many diseases, including cancers, liver diseases, neuroinflammation, and inflammatory bowel disease.
10–13 GA exhibits broad-spectrum antimicrobial activities, including antifungal, antibacterial, and antiviral in vitro.
14 GA significantly inhibited
Trichophyton rubrum growth by repressing the activity of two key enzymes involved in fungal ergosterol biosynthesis, squalene epoxidase, and sterol 14α-demethylase P450 (CYP51), to interfere with fungal membrane integrity,
15 and the fungicidal efficiency was comparable to fluconazole.
14 Recently, GA extracted from
Cassia fistula has been shown to have a potent antifungal activity on fluconazole-resistant
Candida species isolated from patients with HIV,
16 whereas the antifungal mechanisms remain unclear.