Antiviral Effect Of Alternanthera Philoxeroides Microemulsion On Coxsackie Virus Group B₃ In Vitro

Objective:To meet the demands on the performance of pharmaceutical formations with respect to such as storage stability,decreased dosage level,higher bioavailability,fewer side effects, we prepared oil in water(O/W) microemulsion formulation containing the extract from Alternanthera philoxeroides and evaluated its quality. We investigated the antiviral activity on Coxsackie virus Group B₃ (CVB₃) of the Alternanthera philoxeroides microemulsion in vitro and illustrated the possible mechanism, with a view to providing a new therapeutic drug for curing the diseases caused by CVB3.Method:The formulations of the microemulsion were optimized by studying the pseudoternary phase diagrams. We chose the system contained of non-ironic surfactant emulsifier Cremophor EL-35/ethanol/IPM/water. The different ratio of Cremophor EL-35 to ethanol(Km) and different ratio of oil to water were measured. The conductance, viscosity, morphology, particle size distribution, Alternanthera philoxeroides concentration and stability of the microemulsion were studied. The antiviral effect of Alternanthera philoxeroides microemulsion on Coxsackie virus group B3 in vitro was evaluated by means of observing cytopathic effect (CPE) and adopting MTT colorimetric assay for the assessment of cell viability, calculating virus inhibition rate. CVB RNA was detected by reverse transcription polymerase chain reaction (RT-PCR) in HEp-2 cells supernatant.Results:1 , The antiviral extract from Alternanthera philoxeroides contains Coumarin.2 , The optimization of formulation was completed successfully. Km showed predominant influence on the area of microemulsion. The area of microemulsion was larger when the Km was 3:2. The average droplet size was about 32 nm. The studied microemulsion system showed good stability. The average recovery as determined byhigh-performance liquid chromatography was 96.13%, and the mean RSD was 0.21%(n=6).3, In the antiviral test, TC50 was 1.26 mg-mL^\and EC50 was under 50 (igmL'.TI was about 27. The blank microemulsion had no side effect on HEp-2 cells when the concentration was under 20%. The inhibitory activities positively correlated to the concentration of Alternanthera philoxeroides microemulsion. There was significant difference between the Alternanthera philoxeroides microemulsion group and the Alternanthera philoxeroides group.Conclusions:1 -. Microemulsion is a good drug delivery system for the extract from Alternanthera philoxeroides.2> The Alternanthera philoxeroides microemusion is easy to prepare with consistent quality.3^ These results indicated that the Alternanthera philoxeroides microemulsion can interrupt viral biosynthese more effectively than the Alternanthera philoxeroides do,and the former is safer.