Peganum harmala Extract Has Antiamoebic Activity to Acanthamoeba triangularis Trophozoites and Changes Expression of Autophagy-Related Genes

Abstract

Peganum harmala, a well-known medicinal plant, has been used for several therapeutic purposes as it contains numerous pharmacological active compounds. Our study reported an anti-parasitic activity of P. harmala seed extract against Acanthamoeba triangularis. The stress induced by the extract on the surviving trophozoites for Acanthamoeba encystation and vacuolization was examined by microscopy, and transcriptional expression of Acanthamoeba autophagy-related genes was investigated by quantitative PCR. Our results showed that the surviving trophozoites were not transformed into cysts, and the number of trophozoites with enlarged vacuoles were not significantly different from that of untreated control. Molecular analysis data demonstrated that the mRNA expression of tested AcATG genes, i.e., ATG3, ATG8b, and ATG16, was at a basal level along the treatment. However, upregulation of AcATG16 at 24 h post treatment was observed, which may indicate an autophagic activity of this protein in response to the stress. Altogether, these data revealed the anti-Acanthamoeba activity of P. harmala extract and indicated the association of autophagy mRNA expression and cyst formation under the extract stress, representing a promising plant for future drug development. However, further identification of an active compound and a study of autophagy at the protein level are needed.

Curcumin effect on Acanthamoeba triangularis encystation under nutrient starvation

“…In addition, the real-time PCR analysis revealed that the tested ATG genes were similar to those of curcumin treatment under starved condition except Ac ATG16 that up-regulated at later time points. The increased expression of Ac ATG16 was also observed in Peganum harmala seed extract-treated A. triangularis ( Boonhok et al, 2021a ); however, in Cassia angustifolia extract treatment, the increase in Ac ATG16 mRNA was not observed ( Boonhok et al, 2021b ). This may indicate a role of Atg16 in A. triangularis responses to the specific stress signal in autophagy or other cellular pathways, which requires further investigations.…”

“…In Acanthamoeba , starvation conditions are able to induce Acanthamoeba encystation at different degrees, depending on the medium formulation, time, and Acanthamoeba spp. ( Aqeel et al, 2013 ; Sohn et al, 2017 ; Boonhok et al, 2021a ). In our study, starvation by Page’s Saline buffer (PAS) supplemented with 5% glucose was utilized.…”

“…Parasites were treated with curcumin at a final concentration of 50 µg/mL and incubated at room temperature for 24 h. Then, the parasites were harvested every 6 h after treatment (6, 12, 18, 24 h). Parasite preparation for RNA extraction and cDNA synthesis were performed as described by Boonhok and his colleagues ( Boonhok et al, 2021a ). The cDNA was kept at −20 °C until use.…”

“…To confirm primer specificity, the PCR product was sent for sequencing (Apical Scientific Sdn. Bhd., Seri Kembangan, Selangor, Malaysia), and the DNA sequence was then analyzed and blasted against A. castellanii NCBI databases before performing a quantitative PCR ( Boonhok et al, 2021a ).…”

Anti-Acanthamoeba activity of a semi-synthetic mangostin derivative and its ability in removal of Acanthamoeba triangularis WU19001 on contact lens

“…This may be due to a lack of acanthopodia which is the main adhesive structure of trophozoites used for the surface attachment such as contact lenses ( Sangkanu et al, 2022 ). Moreover, Acanthamoeba cells change to irregularly shaped cells and rounded trophozoites in response to the compound in order to protect themselves from environmental conditions such as stress ( Boonhok et al, 2021 ). Based on this experiment, C1 is considered as a potential candidate for future studies mainly to demonstrate the actual role of this compound against other pathogenic Acanthamoeba infections and to explore the potential pharmaceutical applications in the future.…”