Complex sentence: Estragole is the primary constituent of essential oil of tarragon (comprising 60--75%), pine oil, turpentine, fennel, anise (2%), "Clausena anisata" and "Syzygium anisatum".
Split into simpler sentences: Estragole is the primary constituent of essential oil of tarragon (comprising 60--75%). It is also present in pine oil, turpentine, fennel, anise (2%), "Clausena anisata" and "Syzygium anisatum".