- Antiviral and antioxidant activity of flavonoids and proanthocyanidins from Crataegus sinaica. Shahat, A.A., Cos, P., De Bruyne, T., Apers, S., Hammouda, F.M., Ismail, S.I., Azzam, S., Claeys, M., Goovaerts, E., Pieters, L., Vanden Berghe, D., Vlietinck, A.J. Planta Med. (2002)