Phenolic compounds and antimicrobial activity of extracts ofapricot leaves derived from the trees treated with pesticides

Abstract

Background: The apricot tree (Armeniaca vulgaris L.; family Rosaceae) is one of the most important fruit trees in
Armenia. While apricots are widely studied for their alimentary uses (e.g., fresh and dried fruits, and oil production), the leaves are valued in traditional medicine due to their high concentration of bioactive compounds. These compounds make apricot leaves valuable for both medicinal and chemical applications. The healing properties of apricot leaves are primarily attributed to their antimicrobial and antioxidant activities, which are linked to chemical constituents such as flavonoids and phenolic compounds. However, the increasing use of agrochemicals may influence the content of these bioactive compounds and negatively affect their properties. Despite this concern, studies addressing these issues remain scarce in literature.

Objectives: To evaluate the impact of pesticides (Topaz and Confidor) on flavonoid and total phenolic content in apricot leaves through field surveys and biochemical analyses and to identify correlations between the phenolic content in the extracts and the antimicrobial activities of the examined samples.

Methods: The experiments were conducted in the Kotayk region of the Republic of Armenia (RA). The research material was the apricot leaves collected from the trees treated twice with the fungicide Topaz and the insecticide Confidor, after allowing for complete detoxification in the leaves. Trees sprayed with water served as a control group. Antimicrobial activity of the extracts was evaluated using the agar well diffusion assay (Method of Wells). Polyphenolic compounds were quantified using methods described by Yermakov.

Results: According to the results obtained, the inhibitory activity of the apricot leaf extracts against the tested
microorganisms (Gram positive (Staphylococcus citreus, Staphylococcus aureus, Bac. megatherium, B. subtilis), Gram negative bacteria (Escherichia coli and Salmonella thyphymurium) and fungus (Candida guillermondii) is correlated with the concentration of total phenolic compounds, tannins and flavonoids in the leaves by polynomial 3 order equations.

Conclusions: Our data indicates a certain impact of pesticides on the content of the total PC, tannins and flavonoids in apricot leaves, which explains the different antimicrobial activity on the same microorganisms of the tested extracts coming from.

Keywords: Apricot leaves, phenolic compounds, antibacterial and antifungal activities, pesticides