Decne is an important medicinal species used in indigenous medicinal herbal drugs to cure various diseases in South Asia (Pakistan, India and Afghanistan) and in the Middle East (e.g. Saudi Arabia, Qatar, United Arab Emirates (UAE), Iran and Iraq). Some of its alkaloids have been reported to have anticancerous properties. The aim of our study is to examine the morphological and taxonomical parameters for in the Saudi Arabia; concentrations and distributions of some secondary metabolites; and also to determine the antioxidant and free radical scavenging activity. The results of present study showed that there was no influence of environment on the structure of stomata and trichomes as studying species with . In conclusion our study shows no trichomes on leaf of it is glabrous, whereas, variations between many secondary metabolites such as flavonoids and phenolic compounds occurred in response to changing climatic conditions.