New antileishmanial sesquiterpene coumarins from Ferula narthex Boiss - Bashir, S; Alam, M; Adhikari, A; Shrestha, R L; Yousuf, S; Ahmad, B; Parveen, S; Aman, A; Iqbal Choudhary, M (Phytochem Lett, 2014)