Isolation of xanthine oxidase inhibitor compounds of pekoe fanning black tea and their activity on interferon-­γ production in vivo

Abstract

Isolation of bioactive compounds on pekoe fanning black tea was done. The isolation was guided by xanthine oxidase (XO) inhibitory activity test. On the fractionation and separation steps, the ethyl acetate fraction and subfraction (SB)-­3 had greater on XO activity with percentage of inhibition 71.38% and 74.49% respectively. The purification  steps  obtained  four  compounds  and  they  were  identified  by  spectral  data  of  UV-­Vis,  ¹H-­NMR,  MS,  and  ¹³C- NMR. From spectral data the compounds were known as kaempferol, quercetin, luteolin and myricetin. All isolates were assayed by XO inhibitory and their activity on interferon-­γ (IFN-­γ) production in vivo. Luteolin demonstrated  the  greatest  of  XO  inhibitory  activity  with  IC₅₀  5.06  µg/ml.  On  IFN-­γ  production  indicated  that  quercetin demonstrated the greatest ability with IFN-­ γ production 14.45 pg/ml.