Protozoocidal activity of Stemona collinsiae against Giardia duodenalis

Abstract

Giardia duodenalis is a major pathogen of the gastrointestinal tract, and infections impact both human health and the economy. The ongoing issues with drug resistance and the side effects of current anti-Giardia treatments highlight the urgent need for new therapeutic options. This study focused on investigating the in vitro efficacy of crude extracts of Stemona collinsiae from Thailand against G. duodenalis. S. collinsiae was initially extracted with hexane, followed sequentially by dichloromethane, ethanol, and water. The extracts were tested for growth inhibition against G. duodenalis. Dichloromethane and hexane extracts were highly active against the parasite after 48 h of exposure, with half-maximal inhibitory concentration (IC50) values of 60.77 μg/mL and 66.66 μg/mL, respectively. Both extracts reduced G. duodenalis trophozoite motility and adherence, altered trophozoite architecture, and induced apoptosis. Our findings demonstrate the anti-Giardia activity of S. collinsiae root extracts, especially those of dichloromethane and hexane. Our results will support the potential development of new and effective medications for the treatment of giardiasis.

Keywords: Drug development; Giardia duodenalis; Herbal medicine; Human health; In vitro activity; Stemona collinsiae.

Graphical abstract

Fig. 1

Ethidium bromide/acridine orange (EB/AO) staining of parasites after exposure to different types of S. collinsiae root extract compared with standard (positive control)- and nontreatments (negative control): Intact green cells indicate live (normal) cells, diffused orange staining in the cytoplasm, nucleolar necrosis with red nuclei, degenerative nuclei with diffused nucleolar fragmentation with orange/red staining all indicate cytoplasmic apoptosis; and red staining indicates cell necrosis. ∗∗∗∗: p value < 0.001; ∗: p value < 0.05.

Fig. 2

TLC chromatograms of crude extracts of hexane, dichloromethane, ethanol, and water observed under (A) UV 254 nm, (B) 366 nm, and (C) after spraying with Dragendorff's spray reagent for detecting alkaloids. 1 = hexane crude extract; 2 = dichloromethane crude extract; 3 = didehydrostemofoline reference substance; 4 = ethanol crude extract; 5 = water crude extract. The full, non-adjusted, original images of this figure is shown in Supplementary Fig. 3.

Fig. 3

Detection of didehydrostemofoline in the extracts using LC-MS showed LC chromatograms of didehydrostemofoline in crude extracts of (A) hexane, (B) dichloromethane, (C) ethanol, and (D) water crude, and in (E) didehydrostemofoline reference substance, and (F) MS spectrum of didehydrostemofoline peak appearing at 23.47 ± 0.29 min after detection with the LC–MS method.

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