Diversity in Photosynthetic Pigments and Phytochemical Compounds among Iranian Populations of Inula helenium L.

Abstract

Abstract Elecampane (Inula helenium L.) is a valuable medicinal plant known for its well-documented anticancer, cardioprotective, antibacterial, and anti-inflammatory properties. This study aimed to assess various Iranian elecampane populations by collecting 15 populations from their natural habitats and evaluating them in terms of photosynthetic pigments, phenolic content, and essential oil profiles. The populations exhibited variations in chlorophyll (Chl) and carotenoid content, which were positively correlated with soil potassium and phosphorous levels. Content of total phenolic (TPC), total flavonoids (TFC), and proline varied among the populations, with TPC and proline showing a significant correlation with Chl content. The essential oil (EO) content ranged from 0.13 to 0.26%, with the analysis identifying 33 compounds by GC/MS, comprising over 96% of the EO content. The predominant compounds in the EO profiles included β-elemene, tricyclene, α-pinene, isoalantolactone, and santolina triene. Principal component analysis (PCA) and agglomerative hierarchical clustering (AHC) revealed three classes based on the main EO compositions. Populations in habitats with altitudes of 2000-2400 m, pH levels of 6.5-7, and soils with silt/silt loam texture had higher TPC and EO content. Importantly, different populations exhibited essential oils with highly diverse compositions, with some populations containing compounds absent in others. Except for β-elemene, which was present in all populations, other compounds varied in presence and quantity across different populations. This suggests the potential for obtaining diverse and desired chemotypes of Inula helenium through further research.