2025, Vol. 13, Issue 3, Part D

author(s)
Selin Kara, Mehmet Arda Yilmaz and Ay?e Nur Demir

abstract

The application of salicylic acid (SA) as an elicitor to enhance secondary metabolite biosynthesis in plants has gained increasing attention in sustainable viticulture. Grape leaves, particularly from Halwani and Kamali cultivars, are known to contain bioactive phytochemicals with antioxidant, anti-inflammatory, and therapeutic relevance. However, environmental stressors, inconsistent cultivation practices, and genotypic variations often lead to fluctuations in phytochemical concentrations, necessitating interventions that strengthen the metabolic pathways responsible for polyphenol and flavonoid production. This research evaluates the influence of foliar-applied salicylic acid on the phytochemical composition of grape leaves from Halwani and Kamali cultivars, focusing on total phenolic content, flavonoid concentration, antioxidant activity, and associated biochemical modifications. SA is hypothesized to enhance phenylpropanoid pathway activity, resulting in improved accumulation of phenolics and reactive oxygen species scavenging compounds, ultimately contributing to greater leaf resilience and nutraceutical potential.

Experimental field trials were conducted under controlled vineyard conditions, where varying concentrations of SA were applied at specific phenological stages. Phytochemical parameters were quantified using standard analytical methods, including the Folin-Ciocalteu assay for phenolics, aluminium chloride colorimetric assay for flavonoids, and DPPH radical scavenging assays for antioxidant activity. Results indicated a significant increase in total phenolics and flavonoids in SA-treated vines compared with untreated controls, with cultivar-dependent variations. Halwani leaves demonstrated higher phenolic enrichment, while Kamali showed comparatively greater improvement in antioxidant capacity. The findings support the premise that SA acts as an effective metabolic enhancer in grapevine physiology, with potential implications for functional food production, medicinal plant research, and stress-resilient vineyard management. The research concludes that targeted SA application can be a practical agronomic strategy to optimize the phytochemical profile of grapevine foliage, offering value to both growers and industries utilizing grape-leaf bio actives.