title: Inhibition of cysteine proteases by a natural biflavone: behavioral evaluation of fukugetin as papain and cruzain inhibitor.
abstract: Cruzain is the major cysteine protease of Trypanosoma cruzi, the infectious agent responsible for Chagas disease, and cruzain inhibitors display considerable antitrypanosomal activity. In the present work we elucidated crystallographic data of fukugetin, a biflavone isolated from Garcinia brasiliensis, and investigated the role of this molecule as cysteine protease inhibitor. The kinetic analyses demonstrated that fukugetin inhibited cruzain and papain by a slow reversible type inhibition with K(I) of 1.1 and 13.4 µM, respectively. However, cruzain inhibition was about 12 times faster than papain inhibition. Lineweaver-Burk plots demonstrated partial competitive inhibition for cruzain and hyperbolic mixed-type inhibition for papain. Furthermore, the docking results showed that the biflavone binds to ring C' in the S2 pocket and to ring C in the S3 pocket through hydrophobic interactions and hydrogen bonds. Finally, fukugetin also presented inhibitory activity on proteases of the T. cruzi extract, with IC₅₀ of 7 µM.
authors.affiliation: Department of Biophysics, Federal University of São Paulo, São Paulo, SP, Brazil. diegofarmacia@yahoo.com.br
authors.forename: Diego Magno
authors.initials: DM
authors.lastname: Assis
authors.forename: Vanessa Silva
authors.initials: VS
authors.lastname: Gontijo
authors.forename: Ivan
authors.initials: I
authors.lastname: de Oliveira Pereira
authors.forename: Jorge Alexandre Nogueira
authors.initials: JA
authors.lastname: Santos
authors.forename: Ihosvany
authors.initials: I
authors.lastname: Camps
authors.forename: Tanus Jorge
authors.initials: TJ
authors.lastname: Nagem
authors.forename: Javier
authors.initials: J
authors.lastname: Ellena
authors.forename: Mario Augusto
authors.initials: MA
authors.lastname: Izidoro
authors.forename: Ivarne Luis
authors.initials: IL
authors.lastname: dos Santos Tersariol
authors.forename: Nilana Meza Tenório
authors.initials: NM
authors.lastname: de Barros
authors.forename: Antonio Carlos
authors.initials: AC
authors.lastname: Doriguetto
authors.forename: Marcelo Henrique
authors.initials: MH
authors.lastname: dos Santos
authors.forename: Maria Aparecida
authors.initials: MA
authors.lastname: Juliano
mesh_terms: D044946:Biflavonoids / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D001688:Biological Products / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D003546:Cysteine Endopeptidases / Q000378:metabolism; D015853:Cysteine Proteinase Inhibitors / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D005638:Fruit / Q000737:chemistry; D029760:Garcinia / Q000737:chemistry; D007700:Kinetics; D015394:Molecular Structure; D010206:Papain / Q000037:antagonists & inhibitors* / Q000378:metabolism; D015800:Protozoan Proteins / Q000037:antagonists & inhibitors* / Q000378:metabolism; D013329:Structure-Activity Relationship
chemical_list: D044946:Biflavonoids; D001688:Biological Products; D015853:Cysteine Proteinase Inhibitors; D015800:Protozoan Proteins; C105620:morelloflavone; D003546:Cysteine Endopeptidases; C074032:cruzain, Trypanosoma cruzi; D010206:Papain