Variations in morphological and phytochemical traits of cherry laurel (Prunus laurocerasus L.) in Northern Iran

The increasing global demand for medicinal plants, combined with ongoing forest ecosystem exploitation, highlights the critical need for biodiversity conservation and in-depth scientific research. Cherry laurel (Prunus laurocerasus L.), an evergreen species indigenous to the Hyrcanian forests, boasts noteworthy medicinal properties and is now cultivated worldwide. This study explores the morphological and phytochemical attributes and antioxidant potential of different organs (leaves, fruits, clusters, and seeds) from both wild and cultivated cherry laurel specimens. We collected samples from five distinct locales (Gazoo, Haraz, Vaz, Lavandevil, and Astara) within the Guilan and Mazandaran provinces of northern Iran. Our findings revealed significant phenotypic differences (P < 0.01) among the samples analyzed. Cultivated shrubs generally displayed superior morphological characteristics in their leaves, fruits, and seeds compared to their wild counterparts. It is worth noting that the highest total phenol content (35.5 ± 2.5 mg GAE/g DW) and total flavonoid content (30.8 ± 7.1 mg QE/g DW), along with the greatest antioxidant capacity (0.07 ± 0.02 µmol/g), were observed in the leaves of cherry laurel trees sourced from the Vaz habitat, the highest natural habitat of cherry laurel within the Hyrcanian forests. Comparative analysis of the extracted compounds indicated that chlorogenic acid (39.2 ± 4.3—14.6 ± 0.7), salicylic acid (1.6 ± 0.2—0.5 ± 0.009), and caffeic acid (0.1 ± 0.01—0.05 ± 0.01) were predominantly concentrated in the leaves. Conversely, rutin (0.88 ± 0.02—0.29 ± 0.01) and 3,4-dihydroxybenzoate (0.49 ± 0.02—0.21 ± 0.01) were found in higher concentrations in the fruits. Pearson correlation analysis suggested a positive correlation between environmental factors, particularly altitude (a.s.l.), and both phytochemical traits and antioxidant capacity. In conclusion, cherry laurel plants that thrive in more challenging environments tend to exhibit the richest phytochemical composition and the strongest antioxidant activity. These plants may represent promising candidates for cultivation, given their enhanced phytochemical profiles and antioxidant capabilities. However, further research into their nutritional properties is necessary to fully assess their commercial and health-related advantages.