Linearolactone and Kaempferol Disrupt the Actin Cytoskeleton in Entamoeba histolytica: Inhibition of Amoebic Liver Abscess Development

Abstract

Linearolactone (1) and kaempferol (2) have amebicidal activity in in vitro studies. The type of cell death induced by 1 and 2 and their effects on the virulence of E. histolytica were analyzed by transmission and confocal electron microscopy, reactive oxygen species (ROS) production, and apoptosis, detected by flow cytometry with dichlorofluorescein 2′,7′-diacetate and annexin-V binding, respectively, and confirmed by TUNEL. The interaction of 1 and 2 with actin was analyzed by docking, and the in vivo amoebicidal activity was established with the Mesocricetus auratus model; amebic liver abscess (ALA) development was evaluated by magnetic resonance (MR) and validated post mortem. In vitro, compounds 1 and 2 caused chromatin condensation, intracellular ROS, and loss of actin structures. Coupling analysis showed that they bind to the allosteric and catalytic sites of actin with binding energies of −11.30 and −8.45 kcal/mol, respectively. Treatments with 1 and 2 induced a decrease in ALA formation without toxic effects on the liver and kidney. Thus, compound 1, but not 2, was able to induce apoptosis-like effects in E. histolytica trophozoites by intracellular production of ROS that affected the actin cytoskeleton structuration. In vivo, compound 1 was more active than compound 2 to reduce the development of ALA.

Essential Oils and Terpenic Compounds as Potential Hits for Drugs against Amitochondriate Protists

“…Together with the increase in ROS production, annexin V binding, and DNA fragmentation assays, a possible mechanism of apoptosis-like cell death is suggested. The LL treatment was also able to disarrange the actin cytoskeleton of E. histolytica , which was corroborated by a docking analysis showing that it binds to the allosteric site of actin [ 87 ]. This finding should be further explored in the next steps of research, since actin cytoskeleton signaling pathways are essential for E. histolytica host tissue invasion and therefore represent an attractive target against amebiasis.…”

“…The LL diterpene was able to induce an apoptosis-like effect with the intracellular production of reactive oxygen species (ROS). Moreover, the compound altered the actin cytoskeleton and reduced the development of amoebic liver abscesses (ALA) in the in vivo experiments [ 87 ].…”

Linearolactone Induces Necrotic-like Death in Giardia intestinalis Trophozoites: Prediction of a Likely Target

“…LL is a diterpene that was first isolated from Salvia lineata [ 23 ] and later from S. polystachya [ 11 ]. Previous studies have strongly evidenced its antiprotozoal properties, including giardicidal activities [ 24 ]. So far, there are no reports describing its giardicidal mechanism of action; hence, the present work provides evidence that LL exerts cytotoxic damage at the cellular and molecular level in G. intestinalis .…”

Entamoeba histolytica: Membrane and Non-Membrane Protein Structure, Function, Immune Response Interaction, and Vaccine Development

“…Several drug treatments have indirectly targeted actin, such as Adenophyllum aurantium extract, linearolactone, and kaempferol, which affects the structuration of the actin cytoskeleton [99,100]. However, until now, no immune response study has been reported regarding its interaction with E. histolytica actin.…”