Flavonoids with xanthine oxidase inhibitory activity isolated by guidance of bioassay from Artemisia asiatica Nakai
Artemisia asiatica has been used in the traditional oriental medicine for the treatment of cancer, gastritis, ulcers and other inflammatory disorders. Previous in vivo and human studies demonstrated the antioxidant and anti-inflammatory effects of its formulated EtOH extract DA-9601 on gastro-intestinal injuries. It was stated, that its therapeutic effect is mediated partly through the inhibition of gastric xanthine oxidase (XO) activity, which is a late enzyme of purine catabolism, well known as a major source of reactive oxygen species generation in the pathogenesis of various diseases.
In our experiment the XO inhibitory activity of A. asiatica was investigated, followed by a bioactivity guided fractionation aiming the isolation of the components responsible for the activity. The MeOH extract, and its flavonoid-containing fractions obtained by CC on polyamide, significantly inhibited the XO induced uric acid production. The pure flavonoids were isolated using VLC, CPC and PLC and identified as eupatilin, jaceosidin, hispidulin, chrysoplenetin, cirsilineol, 5,7,4'-trihydroxy-6,3',5'-trimethoxyflavon and 5,7,4',5'-tetrahydroxy-6,3'-dimethoxy-flavon by means of UV, NMR and MS. With except of chrysoplenetin and cirsilineol, all compounds exerted remarkable XO inhibitory effect with IC50 values between 1.18–16.69µM.
Acknowledgements: This work was supported by the New Hungary Development Plan projects TÁMOP-4.2.1/B-09/1/KONV-2010–0005 and TÁMOP-4.2.2/B-10/1–2010–0012.