Phytochemical profile and antioxidant activity of almond (Prunus amygdalus Batsch.) cultivars from northwestern Iran

The phytochemical diversity and antioxidant potential of five almond (Prunus amygdalus Batsch.) cultivars from northwestern Iran were systematically investigated. To our knowledge, this study provides the first integrated comparison of phenolic compounds, vitamins, antioxidant activity, and individual phenolics quantified by HPLC in these local Iranian cultivars. Significant cultivar-dependent variation was observed across all measured traits. Among the cultivars, “Yamatga Shabestar” exhibited the highest total phenolic content (1.07 mg GAE g⁻¹ DW), along with elevated levels of flavonoids, tannins, and α-tocopherol, and the strongest antioxidant activity measured by the ferric reducing antioxidant power (FRAP) assay. (0.010 mmol Fe²⁺ g⁻¹ DW). In contrast, “Azar Tasuj” showed consistently lower values (0.12 mg GAE g⁻¹ DW and 0.002 mmol Fe²⁺ g⁻¹ DW). HPLC analysis identified seven major phenolic compounds, with gallic acid reaching 13.5 mg 100 g⁻¹ DW and quercetin enriched in “Yamatga Shabestar,” while catechin was most abundant in “Sangi Azarshahr.” Multivariate analysis further distinguished “Yamatga Shabestar” as metabolically distinct and closely associated with phenolic, and antioxidant related traits. However, given the influence of environmental variability and the limited sampling scope, these findings should be interpreted as a preliminary data survey. Overall, the results suggest the strong potential of “Yamatga Shabestar” as a cultivar–environment combination for future breeding-oriented studies and for the development of functional food and nutraceutical applications.