Preliminary study of the active ingredients against WSSV in guava leaf water-extract

Guava leaf water -extract was separated preliminarily using organic solvent extraction method. Four components in petroleum ether phase (S), ethyl acetate phase (Y), n-butanol phase (Z) and water (W) were collected separately. The challenge test results showed that there were no deaths observed after shrimp infected by white spot syndrome virus (WSSV) incubated with the components in ethyl acetate phase (Y) or n-butanol phase (Z), respectively, but the shrimp started to die after infected by WSSV incubated with the components in petroleum ether phase (S) 5 d, and all died after 12 d. WSSV was incubated with guava leaf water-extract and its extraction content at different time and quantified qPCR. The results showed that the number of WSSV decreased with time passing whether in experimental group or in control group, but still remained at a high level at 120 h. The naked deoxyribonucleic acid (DNA) of WSSV was incubated with guava leaf water -extract and four extraction component respectively, no significantly differences of WSSV gene number were observed comparing to that at the experiment starting (P>0.05).