S. Ray et al., AMAROGENTIN, A NATURALLY-OCCURRING SECOIRIDOID GLYCOSIDE AND A NEWLY RECOGNIZED INHIBITOR OF TOPOISOMERASE-I FROM LEISHMANIA-DONOVANI, Journal of natural products, 59(1), 1996, pp. 27-29
A MeOH extract of Swertia chirata found to inhibit the catalytic activ
ity of topoisomerase I of Leishmania donovani was subjected to fractio
nation to yield three secoiridoid glycosides: amarogentin (1), amarosw
erin (2), and sweroside (3). Amarogentin is a potent inhibitor of type
I DNA topoisomerase from Leishmania and exerts its effect by interact
ion with the enzyme, preventing binary complex formation.