Journal of Rangeland

Gundelia tournefortii (L.) as a medicinal plant species grows spontaneously in the mountains and steep rocky areas. It belongs to Astraceae family. Growth and yield of this species in various ecosystems and natural habitats are affected by many environmental factors (e.g. altitude, climate and soil characteristics). The aim of this study was to investigate the impact of environmental factors on the antioxidant capacity of G. tournefortii in different growth stages in Oshtorankooh rangeland - Lorestan province. For this purpose, leaves and stems of G. tournefortii were collected from 4 sites located in various elevation ranges (1900m - 2700m from sea level with elevation intervals of 200 m) in three stages of maturity. Dried powder of aerial parts from 4 sites was extracted with methanol 80%. Antioxidant activity of the extracts were then analyzed by 2,2-diphenyl-1-picryllhyrazyl (DPPH) method. Statistical analysis of the data was performed by Multivariate Analysis of Variance (MANOVA) to compare the means. The highest antioxidant activity of leaves and stems of G. tournefortii was observed in 1900-2100 m elevation. A significant relationship (p<0.05) was identified between elevation, soli factors and IC₅₀ values of Methanolic extract. Pearson correlation analysis showed that elevation, lime and sand percentage have positive correlation and silt, clay percent, EC and pH have negative correlation with IC₅₀ values for Methanolic extract. The results showed that the plants secondary compounds contents may vary based on  weather conditions.