Within nutraceutical agents of current research, flavonoids are a large family of plant secondary metabolites characterised by a diphenylpropane structure. These are present in vegetables, seeds, fruits and beverages such as wine and beer.⁵ Their high antioxidant capacity led to the study of various protective effects against oxidative damage phenomena. It has even been reported that these active principles have various therapeutic properties to treat atherosclerosis, cancer and ischemic heart disease⁶ although from recent studies their antiprotozoal role stands out.⁷ Kaempferol (KPF) is a member of this family that has shown biological activity as antiprotozoal agent; particularly the antigiardial activity was determined using in vitro and in vivo models;^8,9,10 however, little is known about its mechanism of action on protozoa. In this sense, preliminary in silico studies reported that KFP could act on the enzyme pyruvate: ferredoxin oxidoreductase.⁹ In other parasites such as Entamoeba histolytica, it has been suggested that this flavonoid alters functions related to structural proteins of the cytoskeleton.¹¹

Linearolactone (LL) is a neo-clerodane type diterpene that has been shown to exert giardicidal effects; however, its mechanism of action is unknown. This work analyzes the cytotoxic effect of LL on Giardia intestinalis trophozoites and identifies proteins that could be targeted by this active natural product. Increasing concentrations of LL and albendazole (ABZ) were used as test and reference drugs, respectively. Cell cycle progression, determination of reactive oxygen species (ROS) and apoptosis/necrosis events were evaluated by flow cytometry (FCM). Ultrastructural alterations were analyzed by transmission electron microscopy (TEM). Ligand–protein docking analyses were carried out using the LL structure raised from a drug library and the crystal structure of an aldose reductase homologue (GdAldRed) from G. intestinalis. LL induced partial arrest at the S phase of trophozoite cell cycle without evidence of ROS production. LL induced pronecrotic death in addition to inducing ultrastructural alterations as changes in vacuole abundances, appearance of perinuclear and periplasmic spaces, and deposition of glycogen granules. On the other hand, the in silico study predicted that GdAldRed is a likely target of LL because it showed a favored change in Gibbs free energy for this complex.

Several studies with kaempferol (KP) and linearolactone (LL) have demonstrated their antiparasitic activity. However, the toxicity of these treatments is unknown. Therefore, this study aimed to evaluate the possible toxicological effects of intraperitoneal (i.p.) administration of KP or LL on the amoebic liver abscess model (ALA) in Mesocricetus auratus. An ALA was induced in male hamsters with 1.5 × 10⁵Entamoeba histolytica (E. histolytica) trophozoites inoculated in the left hepatic lobe. The lesion evolved for 4 days, and then KP (5 mg/kg body weight/day) or LL (10 mg/kg body weight/day) was administered for 4 consecutive days. Then, magnetic resonance imaging (MRI), paraclinical analyses, and necropsy for histopathological evaluation were performed. There was similar ALA inhibition by KP (19.42%), LL (28.16%), and metronidazole, the antiamoebic control (20.87%) (p ≤ 0.05, analysis of variance [ANOVA]). There were hepatic and renal biochemical alterations in all treatment groups, mainly for KP (aspartate aminotransferase: 347.5 ± 37.5 U/L; blood urea nitrogen: 19.4 ± 1.9 g/dL; p ≤ 0.05, ANOVA). Lesions found in the organs were directly linked to the pathology. In conclusion, KP and LL decreased ALA development and exerted fewer toxicological effects compared with metronidazole. Therefore, both compounds exhibit therapeutic potential as an alternative treatment of amoebiasis caused by E. histolytica. However, additional clinical studies in different contexts are required to reaffirm this assertion.

Ilama leaves are an important source of secondary metabolites with promising anticancer properties. Cancer is a disease that affects a great number of people worldwide. This work aimed to investigate the in vivo, in vitro and in silico anticancer properties of three acyclic terpenoids (geranylgeraniol, phytol and farnesyl acetate) isolated from petroleum ether extract of ilama leaves. Their cytotoxic activity against U-937 cells was assessed using flow cytometry to determine the type of cell death and production of reactive oxygen species (ROS). Also, a morphological analysis of the lymph nodes and a molecular docking study using three proteins related with cancer as targets, namely, Bcl-2, Mcl-1 and VEGFR-2, were performed. The flow cytometry and histomorphological analysis revealed that geranylgeraniol, phytol and farnesyl acetate induced the death of U-937 cells by late apoptosis and necrosis. Geranylgeraniol and phytol induced a significant increase in ROS production. The molecular docking studies showed that geranylgeraniol had more affinity for Bcl-2 and VEGFR-2. In the case of farnesyl acetate, it showed the best affinity for Mcl-1. This study provides information that supports the anticancer potential of geranylgeraniol, phytol and farnesyl acetate as compounds for the treatment of cancer, particularly with the potential to treat non-Hodgkin’s lymphoma.

Several studies with kaempferol (KP) and linearolactone (LL) have shown antiparasitic activities. However, the toxicity of treat-ments with both active principles is unknown. Therefore, this study aimed to evaluate the toxicological effects of treatments with KP and LL on the amoebic liver abscess (ALA) model in M. auratus administered intraperitoneally (i.p.). For this, ALA in-duction was carried out in male hamsters with 1.5 x105 E. histolytica trophozoites inoculated in the left hepatic lobe. The lesion evolved for four days and the i.p. of the treatments with KP (5 mg/kg body weight/day) and LL (10 mg/kg body weight/day) was carried out for four consecutive days. For histopathological evaluation, NMR studies, paraclinical analysis, and necropsy were performed. The results revealed that the inhibition of ALA by KP and LL were similar to that metronidazole (MTZ). Biochemical parameters revealed hepatic and renal alterations in all treatment groups, mainly for KP (AST and BUN). The lesions found in the organs were those that are directly linked to the pathology. In conclusion, KP and LL decrease ALA development but have few toxicological effects. Both compounds combined with MTZ could be therapeutic alternatives for amoebiasis caused by E. histolytica.