Enhancing biological activities and phenolic content of wild grapevine roots by severe drought stress

Abstract

Wild grapevines are a rich source of polyphenolic compounds. Various environmental factors can influence these bioactive metabolites, contributing to stress mitigation and adaptation. The present study aimed to investigate the impact of prolonged drought stress on the accumulation of phytochemicals, antioxidants, and antimicrobial activity in the roots of the endangered Tunisian wild grapevine (Vitis vinifera subsp. sylvestris) "Tebaba" genotype. The results revealed that under prolonged drought stress, there was a significant increase in total phenolic compounds, total flavonoid content, and stilbenes, which showed a positive and significant correlation with the total antioxidant activity. Furthermore, the ethanolic extracts demonstrated an enhanced in vitro antibacterial effect against selected human pathogenic bacterial strains, including Staphylococcus aureus, Methicillin-resistant S. aureus, and Enterococcus faecalis. The minimum inhibitory concentration (MIC) and the minimal bactericidal concentration (MBC) values, relative to prolonged drought stress, ranged from 125 to 250 µg/mL. The values of the ratio between MBC and the MIC showed that the activity of the root extract was bactericidal in all cases (MBC/MIC ≤ 2). This study highlights the potential of wild grapevine roots enriched with drought-inducible phenolic compounds, as a promising source of antimicrobial agents relevant to human health applications.

Graphical Abstract

Keywords:

• Drought stress
• wild grapevine
• roots
• antibacterial activity
• antioxidants
• phenolics
• stilbenes

Authors’ contributions

S.D. conceived and designed the study. S.D. and F.H. conducted research including greenhouse culture, physiological and biochemical analysis. F.H. performed stilbene analysis. S.V. supervised HPLC analysis. F.H., N.F. and O.T. performed antimicrobial studies. S.D. and M.G. conceived the graphical abstract. S.D. wrote the manuscript. All authors read and contribute to the review and editing of the final manuscript.

Disclosure statement

The authors declare that they have no competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Additional information

Funding

This research was supported by the Tunisian Ministry of Higher Education and Scientific Research.