Optimization of xanthatin extraction from Xanthium spinosum L. and its cytotoxic, anti-angiogenesis and antiviral properties.

The aqueous extraction of the sesquiterpene lactone xanthatin from Xanthium spinosum L. favours the conversion of xanthinin (1) to xanthatin (2) via the loss of acetic acid. The cytotoxic (Hep-G2 and L1210 human cell lines) and antiviral activities of isolated xanthatin are established. This natural compound shows significant cytotoxicity against the Hep-G2 cell line and our experimental results reveal its strong anti-angiogenesis capacity in vitro. The structure of xanthatin is determined by spectroscopic methods and for the first time confirmed by X-ray diffraction.