Development of Microemulsion of Phytosteryl Glycoside in DMSO and Tween 20 for Increase Antiamoebic Activity

Abstract

Peperomia pellucida (Piperaceae) of Thai name “Phak kra sang” is medicinal plant. They are eaten in a salad or as cooked vegetable for protected glaucoma, eye inflammation. Recently, The methanol fraction of P. pellucida was tested for antiamoebic effect. Acanthamoeba spp. are protozoa, free-living in the environment and feed on bacteria. Acanthamoeba spp. are the causative agents of Acanthamoeba keratitis. P. pellucida is medicinal plants, and was interesting for studied antiamobic. The separation by column chromatography (CC) used organic solvent of methanol and ethyl acetate (3:7) gave phytosteryl glycoside (PG). Acanthamoeba spp. was cultured in normal saline and PG is organic compound which was poor soluble in normal saline. This study was developed microemulsion (ME) of PG for effective of antiamoebic activity. Pseudo-ternary phase diagram used for identify ME region. The consisting of ME were dimethyl sulfoxide (DMSO), Tween 20, water and PG. Formulations were prepared with prior mixture of DMSO: Tween20 (co-surfactant: surfactant) in four volume ratio 1:1, 2:1, 3:1 and 4:1 which is each of ratio of Smix. PG was concentrated in 200μg/ml in ethanol. Forming of colloids used Smix in ratios 3:1and 4:1.The stability of ME was ratio was PG: Smix water (1: 9: 4.5). The optimized ME formulation and characterized by zeta potential were found to be 121-397 nm, and conductivity-7.0 mV. Under light microscope ME was absorbed into the endocyst of Acanthamoeb spp., and detected the dead cysts by staining of toluidine blue. IC50 showed 0.88 μg/ml for antiamoebic activity.