Total Phenolic Fraction (TPF) from Extra Virgin Olive Oil: Induction of apoptotic-like cell death in Leishmania spp. promastigotes and in vivo potential of therapeutic immunomodulation

Abstract

Background Leishmaniasis is a serious multifactorial parasitic disease with limited treatment options. Current chemotherapy is mainly consisted of drugs with serious drawbacks such as toxicity, variable efficacy and resistance. Alternative bioactive phytocompounds may provide a promising source for discovering new anti-leishmanial drugs. Extra Virgin Olive Oil (EVOO), a key-product in the Mediterranean diet, is rich in phenols which are associated with anti-inflammatory, anti-cancer and anti-microbial effects. In this study, we investigate the anti-leishmanial effect of Total Phenolic Fraction (TPF) derived from EVOO in both in vitro and in vivo systems by investigating the contributing mechanism of action. Methodology/Principal findings We tested the ability of TPF to cause apoptotic-like programmed cell death in L. infantum and L. major exponential-phase promastigotes by evaluating several apoptotic indices, such as reduction of proliferation rate, sub-G0/G1 phase cell cycle arrest, phosphatidylserine externalization, mitochondrial transmembrane potential disruption and increased ROS production, by using flow cytometry and microscopy techniques. Moreover, we assessed the therapeutic effect of TPF in L. major-infected BALB/c mice by determining skin lesions, parasite burden in popliteal lymph nodes, Leishmania-specific antibodies and biomarkers of tissue site cellular immune response, five weeks post-treatment termination. Our results show that TPF triggers cell-cycle arrest and apoptotic-like changes in Leishmania spp. promastigotes. Moreover, TPF treatment induces significant reduction of parasite burden in draining lymph nodes together with an antibody profile indicative of the polarization of Th1/Th2 immune balance towards the protective Th1-type response, characterized by the presence of IFN-γ-producing CD4+ T-cells and increased Tbx21/GATA-3 gene expression ratio in splenocytes. Conclusions/Significance TPF exhibits chemotherapeutic anti-leishmanial activity by inducing programmed cell death on cell-free promastigotes and immunomodulatory properties that induce in vivo T cell-mediated responses towards the protective Th1 response in experimental cutaneous leishmaniasis. These findings enable deeper understanding of TPF’s dual mode of action that encourages further studies.

Exploring the Immunotherapeutic Potential of Oleocanthal against Murine Cutaneous Leishmaniasis

“…OLEO exhibited an inhibitory effect in vitro against both the promastigote and intracellular amastigote forms of L. major parasites. These results are in accordance with our previous studies, indicating an OLEO-enriched phenolic fraction with a powerful inhibitory effect against L. major promastigotes and amastigotes 10 . Additionally, these data are in line with a recent study also demonstrating a powerful inhibitory effect of another natural product, 6-gingerol, against L. major promastigotes 23 .…”

“…The segregation of IgG2a and IgG1 isotypes has been extensively used as a surrogate marker of protective Th1 and exacerbating Th2 responses, respectively 37 . These findings are in accordance with our previous study where mice treated with the OLEO-enriched phenolic fraction also exhibited a higher IgG2a/IgG1 ratio 10 . The prevalence of Th1 immunity after treatment with OLEO was further validated by the induced IL-12 cytokine 38 .…”

“…Moreover, it has been associated with in vitro antimicrobial properties 8 . Our previous studies with an OLEO-enriched crude extract (TPF) and other pure natural agents, all derived from olive products, revealed their strong antileishmanial and immunomodulatory properties in in vitro and in vivo systems 10 , 11 , 12 . Additionally, various other studies demonstrated medicinal products of the olive tree that possess antileishmanial properties 13 , 14 , enhancing the position of the olive tree as a promising source for antileishmanial compounds.…”

Compostos bioativos presentes no azeite de oliva e seus subprodutos: revisão bibliográfica

“…Outras propriedades dos compostos bioativos presentes no azeite de oliva se referem a melhor liberação de insulina pósprandial (Sanchez-Rodriguez et al, 2021), regulação do metabolismo e resistência muscular (Luzi et al, 2021), neuroprotetor aliviando disfunção cognitiva no Alzheimer (Qin et al, 2021), efeito anti-leishmaniose (Karampetsou et al, 2021).…”

Direct In Vitro Comparison of the Anti-Leishmanial Activity of Different Olive Oil Total Polyphenolic Fractions and Assessment of Their Combined Effects with Miltefosine

“…Our group has showcased the anti-leishmanial properties of olive oil phenolic compounds by demonstrating that pure oleuropein and oleocanthal (OLEO) exert anti-leishmanial properties in vitro and promote in vivo efficacy in murine experimental models of VL and CL [ 23 , 24 , 25 , 26 ]. In addition, we have reported that TPF exhibits chemotherapeutic anti-leishmanial activity in vitro and in vivo [ 27 , 28 ].…”