Isolation and identification of chemical constituents in effective fraction anti-PRRSV of the branches and leaves of the Lonicera japonica

The antiviral effect of the extracts of the Lonicera japonica leaves on PRRSV in vitro was evaluated by determining the minimum protection concentration on PRRSV infected Marc-145 cell and TCID50.The results showed that the 60% ethanol/water elution fraction possess the perfect protective effect on PRRSV infected cell and with the minimum protection concentration of 6.25 μg/mL.The 6.25 μg/mL 60% ethanol/water elution fractions decreased PRRSV titer from 105.8 TCID50 to 100.3 TCID50.That is to say,60% ethanol/water elution fractions of Lonicera japonica is a potential antiviral drug owing to its perfect anti-PRRSV effect.To study the chemical constituents of the Lonicera japonica,the air-dried branches and leaves of this plant were extracted with 95% ethanol.The extracts were separated and purified by normal-phase,Sephadex LH-20 and RP-HPLC.Five compounds were obtained from the effective fractions anti-PRRSV of the branches and leaves of the Lonicera japonica and their structures were identified as Dihydrodehydrodiconiferyl alcohol 4′-O-β-D-glucoside(1),Apigenin 5-O-β-D-glucopyranoside(2),Secoxyloganin(3),Benzyl alcohol O-(6′-O-β-D-xylopyranosyl)-β-D-glucopyranoside(4) and Sweroside(5).