Abstract
This study aims to compare five species of Heliotropium collected from Jazan region, Kingdom of Saudi Arabia. This comparison was carried out on basis of morphology, pigments content, proteins, total phenolics, flavonoids as well as their antioxidant activity. According to similarity matrix and cluster analysis, H. longiflorum and H. zeylanicum were closely related while H. pterocarpum and H. zeylanicum were distantly related species. The variation in pigments content of the five studied species of Heliotropium was obvious. H. zeylanicum recorded the highest content of pigments while H. bacciferum was the lowest. Moreover, H. jizanense and H. pterocarpum had almost similar pigments content. Proteins, phenolics and flavonoids showed noticeable variation among the tested species. In other words, H. zeylanicum and H. bacciferum had the highest contents of proteins, phenolics and flavonoids and H. jizanense had lowest and the difference was significant. Meanwhile, the total antioxidant activity was variable among species. Higher antioxidant activity was detected in H. zeylanicum (93%) and H. bacciferum (84%) while H. pterocarpum (34.5%).