Licochalcone a: A promising antiparasitic drug against giardiasis

Abstract

Giardiasis, caused by Giardia duodenalis, is a prevalent and significant zoonotic disease. While nitroimidazole drugs are primarily used to treat giardiasis, the urgent need for the development and formulation of new drugs has arisen due to increasing drug resistance. Several plant derived medicine have been employed as antiparasitic drugs. This study has evaluated the anti-Giardia effect of Licochalcone A (Lic A) through both in vitro and in vivo experiments. We determined the 50% inhibitory concentration (IC₅₀) of Lic A, analyzed the adhesive ability of G. duodenalis, and assessed intestinal morphology and various indicators in the gerbil model. The in vitro assays demonstrated that the IC₅₀ value of Lic A against G. duodenalis was 27.42 μM. Additionally, Lic A significantly inhibited the adhesiveability of G. duodenalis trophozoites, impairing their cell structure and cytoskeleton. In vivo experiments showed that Lic A significantly mitigated weight loss due to G. duodenalis infection, and lowered the intestinal parasite load. Histopathological examinations in gerbils indicated that Lic A could reduce intestinal damage, increase the height of intestinal villi, decrease crypt depth, and maintain the integrity of intestinal structure. Furthermore, Lic A altered cytokine levels and enhanced the body's antioxidant capacity. In conclusion, Lic A exbibits significant anti-Giardia effects both in vitro and in vivo, suggesting its potential as a promising antiparasitic drug candidate against giardiasis.

Keywords: Against giardiasis; Giardia duodenalis trophozoites; Licochalcone a.

Graphical abstract

Figure 1

Determination of the IC₅₀ of Lic A and metronidazole against G. duodenalisin vitro. (A: IC₅₀ of Lic A; B: IC₅₀ of metronidazole).

Figure 2

Effect of Lic A on the adhesion ability of G. duodenalis trophozoites.

Fig. 3

Structural damage of G. duodenalis trophozoites treated with Lic An under scanning electron microscopy (A–C: blank control group; D–F: solvent control group; G–L: Lic A group; M–R: MTZ group). The black arrow shows the site of structural damage in G. duodenalis trophozoites damage.

Fig. 4

Structural damage of G. duodenalis trophozoites induced by Lic An under transmission electron microscopy (A–C: blank control group; D: solvent control group; E–L: Lic A group; M–P: MTZ group) (N: nucleus; VD: ventral disc; PV: peripheral vesicles; LC: lateral crest; VLF: ventrolateral flange).

Fig. 5

Weight changes, intestinal trophozoites load in gerbils after Lic A treatment (A: weight changes; B: intestinal trophozoites load).

Fig. 6

Lic A Changes in organ indices after treatment (A: liver index; B: spleen index; C: Renal index).

Fig. 7

Results of duodenal pathological sections and statistical analysis after treatment of Lic A (A: blank control group; B–D: infected group; E: high-dose Lic A group; F: medium-dose Lic A group; G–H: low-dose Lic A group; I: MTZ group) (V:Villi; BC:basal crypts; ML:muscular layer) Red circles: damage to the muscularis propria; blue circles: atrophy and disintegration of the villi; blue arrows: intestinal trophozoites; green arrows: deepening of crypts.

Fig. 8

Statistical analysis of duodenal pathological sections after treatment with Lic A. (A: villus height; B crypt depth; C: villus-to-crypt ratio).

Fig. 9

Results of serum cytokine levels (A: IL-1β content; B: IL-6 content; C: IL-10 content; D: IL-17 content; E: TNF-α content; F: IFN-γ content).

Fig. 1Microscopic inhibitory effect of Lic A on Giardia duodenalis trophozoites. A-C: Control group; D-E: Solvent control group; F: 7.39 μM Lic A group; G: 14.78 μM L Lic A group; H: 29.55 μM Lic A group; I: 44.33 μM Lic A group; J: 59.10 μM Lic A group; K: 14.61 μM MTZ group; L: 29.21 μM MTZ group; M: 58.43 μM MTZ group; N: 87.64 μM MTZ group; O: 116.86 μM MTZ group.

Fig. 2Effect of Lic A on the morphology of G.duodenalis trophozoites by Giemsa staining. A-B: Control group; C-D: Solvent control group; E-H: Lic A group; I-L: MTZ group The black arrows in the picture represents the damaged insect bodies.

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