Total polyphenol content and antioxidant capacity of allium plants and their correlation with antibacterial and antifungal activity

Abstract

Aim. To determine the total polyphenols and antioxidant capacity and their correlation with antimicrobial and fungicidal properties in some species of the genus Allium growing in Tajikistan.

Materials and methods. The objects of the study were 15 kinds of the Amaryllidaceae family. Antibacterial onions were studied by the disk diffusion method against 4 types of microorganisms (test strains) and 1 type of yeast fungus. In the presence of total polyphenols, the content in μg of Gallic acid (GA) per ml of plant extract was measured. To determine the antioxidant activity, a solution of ABTS K2S2O8 was used. Trolox was used as a standard.

Results. The maximum content of total polyphenols is characterized by ethanol extracts of A. Carolinianum, A. altaicum, A. elatum, A. oschaninii, A. ramosum, A. hymenorhisum. At the same time, their lowest amount was found in the bulbs of A. longicuspis. A. shoenoprasum, which is statistically significantly lower than in all the above-listed species of this plant group. The extracts from the stems of A. carolinianum, A. elatum, and A. pamiricum had the highest antioxidant effect. There is a direct weak correlation between biologically active components with antimicrobial and fungicidal activity in A. oshaninii and A. suworowii, depending on the altitude gradient.

Conclusions. The results allow suggesting that the above-ground and underground parts of some wild-growing endemic species of the genus Allium have different degrees of antioxidant activity due to total polyphenols. The content of total polyphenols and the antioxidant capacity of extracts obtained from various plants in different in large ranges. In some cases, there are direct correlations between the content of polyphenols, antioxidant properties, antimicrobial and fungal properties.