Percorrer por autor "Wiart, Christophe"
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- Amoebicidal, anti-adhesive, and low-cytotoxic effects of Mangifera indica L. leaf extract against ocular Acanthamoeba spp.: first evidence supporting plant-based therapeutic potentialPublication . Mendonça, Diana; Tabo, Hazel A.; Chimplee, Siriphorn; Oliveira, Sónia M. R.; Kwankaew, Pattamaporn; Girol, Ana Paula; Dungca, Julieta Z.; Sulaiman, Mazdida; Bhassu, Subha; Nawaz, Muhammad; Wilairatana, Polrat; Wiart, Christophe; Dolma, Karma G.; Kayesth, Sunil; Nissapatorn, Veeranoot; Pereira, Maria de LourdesBackground and Aim: Acanthamoeba spp. is free-living protozoa capable of causing severe infections, notably Acanthamoeba keratitis, which is difficult to manage due to cyst resistance and the cytotoxicity of current treatments. Plant-derived compounds represent a promising alternative strategy. This study investigated the amoebicidal, anti-adhesive, and cytotoxic properties of Mangifera indica L. (mango) leaf extract against ocularly relevant Acanthamoeba spp. Materials and Methods: Crude ethanolic leaf extract of M. indica was prepared and evaluated against Acanthamoeba polyphaga American Type Culture Collection (ATCC) 30461 and Acanthamoeba castellanii ATCC 50739. Minimum inhibitory concentration (MIC) and minimum parasiticidal concentration were determined for trophozoites and cysts. Morphological changes were analyzed by scanning electron microscopy (SEM). Anti-adhesion assays were conducted using polystyrene surfaces, with a commercial multipurpose contact lens (CL) solution as a control. Cytotoxicity was tested in Vero cells using the 3-(4, 5-Dimethylthiazol-2-yl)-2, 5-Diphenyltetrazolium Bromide assay to establish the minimum cytotoxic concentration. Results: The extract inhibited trophozoite growth at 2 mg/mL and demonstrated cysticidal activity at 4 mg/mL for A. polyphaga and 32 mg/mL for A. castellanii. SEM revealed disruption of trophozoite morphology, loss of acanthopodia, and surface perforations in cysts. At MIC levels, adhesion was reduced by >70%, and even at 1/8 MIC, inhibition remained above 50%, comparable to a commercial multipurpose solution. Cytotoxicity assessment showed >80% Vero cell viability at 0.125 mg/mL, indicating a favorable therapeutic window. Conclusion: This is the first report demonstrating amoebicidal and anti-adhesive effects of M. indica L. leaf extract against ocular Acanthamoeba species. The dual trophozoiticidal and anti-adhesive actions, combined with low cytotoxicity, highlight its potential for development as a plant-based therapeutic agent, particularly in ocular formulations or CL disinfectants. Future work should focus on phytochemical isolation, mechanistic studies, and novel delivery systems to enhance efficacy and safety.
- Comparative efficacy of Knema retusa extract delivery via PEG-b-PCL, niosome, and their combination against Acanthamoeba triangularis genotype T4: characterization, inhibition, anti-adhesion, and cytotoxic activityPublication . Chimplee, Siriphorn; Mitsuwan, Watcharapong; Zulkifli, Masyitah; Eawsakul, Komgrit; Ongtanasup, Tassanee; Sangkanu, Suthinee; Mahboob, Tooba; Oliveira, Sonia M. R.; Wiart, Christophe; Ramamoorthy, Siva; Pereira, Maria de Lourdes; Saravanabhavan, Shanmuga Sundar; Wilairatana, Polrat; Nissapatorn, VeeranootBackground. Acanthamoeba spp. is a waterborne, opportunistic protozoan that can cause amebic keratitis and granulomatous amebic encephalitis. Knema retusa is a native tree in Malaysia, and its extracts possess a broad range of biological activities. Niosomes are non-ionic surfactant-based vesicle formations and suggest a future targeted drug delivery system. Copolymer micelle (poly(ethylene glycol)-block-poly(?-caprolactone); PEG-b-PCL) is also a key constituent of niosome and supports high stability and drug efficacy. To establish Knema retusa extract (KRe) loading in diverse nanocarriers via niosome, PEG-b-PCL micelle, and their combination and to study the effect of all types of nanoparticles (NPs) on Acanthamoeba viability, adherent ability, elimination of adherence, and cytotoxicity. Methods. In this study, we characterized niosomes, PEG-b-PCL, and their combination loaded with KRe and tested the effect of these NPs on Acanthamoeba triangularis stages. KRe-loaded PEG-b-PCL, KRe-loaded niosome, and KRe-loaded PEG-b-PCL plus niosome were synthesized and characterized regarding particle size and charge, yield, encapsulation efficiency (EE), and drug loading content (DLC). The effect of these KRe-loaded NPs on trophozoite and cystic forms of A. triangularis was assessed through assays of minimal inhibitory concentration (MIC), using trypan blue exclusion to determine the viability. The effect of KRe-loaded NPs was also determined on A. triangularis trophozoite for 24–72 h. Additionally, the anti-adhesion activity of the KRe-loaded niosome on trophozoites was also performed on a 96-well plate. Cytotoxicity activity of KRe-loaded NPs was assessed on VERO and HaCaT cells using MTT assay. Results. KRe-loaded niosome demonstrated a higher yielded (87.93 ± 6.03%) at 286 nm UV-Vis detection and exhibited a larger size (199.3 ± 29.98 nm) and DLC (19.63 ± 1.84%) compared to KRe-loaded PEG-b-PCL (45.2 ± 10.07 nm and 2.15 ± 0.25%). The EE (%) of KRe-loaded niosome was 63.67 ± 4.04, which was significantly lower than that of the combination of PEG-b-PCL and niosome (79.67 ± 2.08). However, the particle charge of these NPs was similar (?28.2 ± 3.68 mV and ?28.5 ± 4.88, respectively). Additionally, KRe-loaded niosome and KRe-loaded PEG-b-PCL plus niosome exhibited a lower MIC at 24 h (0.25 mg/mL), inhibiting 90–100% of Acanthamoeba trophozoites which lasted 72 h. KRe-loaded niosome affected adherence by around 40–60% at 0.125–0.25 mg/mL and removed Acanthamoeba adhesion on the surface by about 90% at 0.5 mg/mL. Cell viability of VERO and HaCaT cells treated with 0.125 mg/mL of KRe-loaded niosome and KRe-loaded PEG-b-PCL plus niosome exceeded 80%. Conclusion. Indeed, niosome and niosome plus PEG-b-PCL were suitable nanocarrier-loaded KRe, and they had a greater nanoparticle property to test with high activities against A. triangularis on the reduction of adherence ability and demonstration of its low toxicity to VERO and HaCaT cells.
- Development of a novel encystment medium: enhancing diagnostic potential of Acanthamoeba spp.Publication . Chuprom, Julalak; Sangkanu, Suthinee; Mitsuwan, Watcharapong; Boonhok, Rachasak; Paul, Alok K.; Oliveira, Sonia M. Rodrigues; Pereira, Maria L.; Jimoh, Tajudeen O.; Rahmatullah, Mohammed; Wilairatana, Polrat; Wiart, Christophe; Verma, Ajoy K.; Nissapatorn, VeeranootBackground and Aim: Acanthamoeba spp. are pathogenic microorganisms linked to severe infections in humans and animals, requiring a deeper understanding of their encystation process for effective diagnostics and research. This study focused on developing a novel encystment medium to induce synchronized encystation of Acanthamoeba spp. efficiently and rapidly. Materials and Methods: The study employed response surface methodology with a central composite design to optimize the encystment medium formulation. The key components included Tris-HCl, NaCl, glucose, and MgCl2 . The optimized liquid medium was spray-dried to produce a dehydrated powder for practical application. The encystation efficiency of different Acanthamoeba strains was assessed using hemocytometry and fluorescence microscopy. Results: The optimized medium, comprising 3.152 g/L Tris-HCl, 5.55 g/L NaCl, 8% (w/v) glucose, and 5.0 mM MgCl2 at pH 9.0, demonstrated exceptional encystation efficiency with rates ranging from 99% to 100%. A spray-dried powdered version of this medium was equally effective, achieving a 98.77% encystation rate for A. castellanii American Type Culture Collection 50739 in glucose-free conditions. Notably, optimal glucose concentrations varied among Acanthamoeba strains, with certain strains reaching maximum encystation at 6–8% glucose. Conclusion: This study successfully developed an innovative encystment medium that promotes rapid and efficient cyst production in Acanthamoeba spp. The medium enhances laboratory research and diagnostic capabilities, paving the way for future advancements in understanding and managing Acanthamoeba infections.