Antimicrobial effects of Allium sativum L. (garlic), Allium ampeloprasum L. (elephant garlic), and Allium cepa L. (onion), garlic compounds and commercial garlic supplement products

Abstract Diallyl thiosulphinate (allicin), methyl allyl thiosulphinate, and allyl methyl thiosulphinate found in aqueous garlic clove and powder homogenates showed in vitro antibacterial and antifungal activities while garlic polar compounds, including alliin, did not. E/Z‐ajoene, a minor but water‐soluble transformation product of allicin found in vegetable oil‐macerates of garlic, demonstrated anticandidal activity. Garlic showed greater antibacterial and antifungal activities than a number of onion types. Garlic and elephant garlic clove homogenates demonstrated similar activity. The anticandidal activities of commercially available garlic supplement products corresponded in general to the activities known for the chemical compounds found in the products.