Phytochemical composition and in vitro antimicrobial and antioxidant activities of essential oils of three endemic Soqotraen Boswellia species

► GC/MS analysis showed variations in the chemical composition from other Boswellia sp. ► Monoterpene hydrocarbons with α-thujene and α-pinene predominated in B. dioscorides. ► B. elongata was characterized by high diterpene content. ► 2-Hydroxy-5-methoxy-acetophenone and camphor were the major compounds in B. socotrana. ► All essential oils possessed a strong antimicrobial but a weak antioxidant activity.