Ultrastructural and proapoptotic-like effects of kaempferol in Giardia duodenalis trophozoites and bioinformatics prediction of its potential protein target

Cytotoxic effects of ivermectin on Giardia lamblia: induction of apoptosis and cell cycle arrest

Introduction

Giardia lamblia is a flagellated protozoan parasite causing giardiasis, a common intestinal infection characterized by diarrhea, abdominal cramps, and nausea. Treatments employed to combat this parasitic infection have remained unchanged for the past 40 years, leading to the emergence of resistant strains and prompting the search for new therapeutic agents.

Methods

This study investigated the cytotoxic effects of ivermectin (IVM) on G. lamblia trophozoites. We conducted dose-response experiments to assess IVM-induced cytotoxicity. We utilized various biochemical and ultrastructural analyses to explore the underlying mechanisms of cell death, including reactive oxygen species (ROS) production, DNA fragmentation, cell cycle arrest, and apoptosis markers.

Results

Our findings demonstrate that IVM induces dose-dependent cytotoxicity and triggers cell death pathways. We found that IVM treatment generates elevated levels of reactive oxygen species (ROS), DNA fragmentation, and arrests of trophozoites in the cell cycle's S phase. Additionally, ultrastructural analysis reveals morphological alterations consistent with apoptosis, such as cytoplasmic vacuolization, chromatin condensation, and tubulin distribution.

Discussion

The insights gained from this study may contribute to developing new therapeutic strategies against giardiasis, addressing the challenge posed by drug-resistant strains.

Pharmacological Potential of Kaempferol, a Flavonoid in the Management of Pathogenesis via Modulation of Inflammation and Other Biological Activities

Natural products and their bioactive compounds have been used for centuries to prevent and treat numerous diseases. Kaempferol, a flavonoid found in vegetables, fruits, and spices, is recognized for its various beneficial properties, including its antioxidant and anti-inflammatory potential. This molecule has been identified as a potential means of managing different pathogenesis due to its capability to manage various biological activities. Moreover, this compound has a wide range of health-promoting benefits, such as cardioprotective, neuroprotective, hepatoprotective, and anti-diabetic, and has a role in maintaining eye, skin, and respiratory system health. Furthermore, it can also inhibit tumor growth and modulate various cell-signaling pathways. In vivo and in vitro studies have demonstrated that this compound has been shown to increase efficacy when combined with other natural products or drugs. In addition, kaempferol-based nano-formulations are more effective than kaempferol treatment alone. This review aims to provide detailed information about the sources of this compound, its bioavailability, and its role in various pathogenesis. Although there is promising evidence for its ability to manage diseases, it is crucial to conduct further investigations to know its toxicity, safety aspects, and mechanism of action in health management.

Kaempferol induces programmed cell death in Naegleria fowleri

BACKGROUND

Naegleria fowleri is a brain-eating amoeba causing a fatal brain infection called primary amoebic meningoencephalitis (PAM). Despite its high mortality over 95%, effective therapeutic drug for PAM has not been developed yet. Therefore, development of an effective and safe therapeutic drug for PAM is urgently needed. In this study, we investigated anti-amoebic effect of kaempferol (KPF) against N. fowleri and its underlying anti-amoebic molecular mechanisms.

METHODS

Anti-amoebic activity of KPF against N. fowleri trophozoites, as well as cytotoxicity of KPF in C6 glial cells and CHO-K1 cells were investigated. The programmed cell death mechanisms in KPF-treated N. fowleri were also analyzed by apoptosis-necrosis assay, mitochondrial dysfunction assay, TUNEL assay, RT-qPCR, and CYTO-ID assay.

RESULTS

KPF showed anti-amoebic activity against N. fowleri trophozoites with an IC50 of 29.28 ± 0.63 μM. However, it showed no significant cytotoxicity to mammalian cells. KPF induced significant morphological alterations of the amoebae, resulting in death. Signals associated with apoptosis were detected in the amoebae upon treatment with KPF. KPF induced an increase of intracellular reactive oxygen species level, loss of mitochondrial membrane potential, increases of expression levels of genes associated with mitochondria dysfunction, and reduction of ATP levels in the amoebae. Autophagic vacuole accumulations with increased expression levels of autophagy-related genes were also detected in KPF-treated amoebae.

CONCLUSION

KPF induces programmed cell death in N. fowleri trophozoites via apoptosis-like pathway and autophagy pathway. KPF could be used as a candidate of anti-amoebic drug or supplement compound in the process of developing or optimizing therapeutic drug for PAM.

Pharmaceutical activity of a synthetic heterocyclic (C15H12N5OCL) compound on Entamoeba histolytica and Giardia lamblia

Abstract: Background: Intestinal parasites are among the most important infectious agents with an impact on human health. Indeed, in the lack of an available treatment option, these parasites could constitute a real health problem in the population. Aim: In the present study, we investigated the effect of a synthetic heterocyclic compound on two intestinal parasites (Entamoeda histolytica and Gardia lamblia). Methods: The parasite isolates tested were collected from outpatients at the General Pediatric Hospital in Kirkuk, Iraq, between September 2019 and January 2020. Thus, we studied the in vivo and in vitro pharmaceutical activity of the ingredient on both parasites. The toxicological effects of the substance on some blood parameters and liver and kidney function tests were also studied. Results: After five days of treatment, the drug's in vivo action on G. lamblia resulted in an inhibition rate of 88.2 percent at a dose of 1 mg/kg. On the other hand, we observed that the influence of this synthetic substance on cultured E. histolytica was very close to the metronidazole effect. The maximum result was at a concentration of 1 g/ml and was obtained after 72 hours of incubation with an inhibition rate of 89.4%. The substance did not affect the blood parameters or the studied liver and kidney functions. Conclusion: It can be concluded that this substance is highly effective against both E. histolytica and G. lamblia, and that it has no toxic effects on the studied parameters. Therefore, it could be a promising pharmacophore for intestinal protozoan parasites including E. histolytica and G. lamblia and an alternative or competitor to the current medications available.

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

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.