New isoflavones from Gynandriris sisyrinchium and their antioxidant and cytotoxic activities.

Chemical investigation of Gynandriris sisyrinchium (L.) Parl growing in Jordan resulted in the isolation and characterization of a total of twelve compounds two of which are reported here for the first time in nature. These new compounds included the isoflavones; 3'-methyl tenuifone (2) and gynandrinone (5). In addition, ten known compounds including; β-sitosterol (1), 7,3'-dimethoxy-5,6,4'-trihydroxyisoflavone (3), iristectorigenin (4), hispidulin (6), galangustin (7), 6-hydroxybiochanin A (8), ursolic acid (9), ladanetin (10), 4'-O-methylgenistein (11) and β-sitosterol glucoside (12) are also reported here for the first time from G. sisyrinchium. The isolated compounds were characterized by different spectroscopic methods including NMR (1D and 2D), UV, IR and MS (HRESIMS and EIMS). The antioxidant and cytotoxic activities of isoflavones 2, 3 and 5 were investigated. Compound 3 showed the highest antioxidant activity (IC50=17.3μg/mL), as compared to compounds 5 and 2 (IC50=26.7 and 51.7μg/mL, respectively). The cytotoxic activity against the human promyelocytic leukemia HL-60 cells revealed that compound 2 was the most active (40μM). The results indicate that the cytotoxicity of compound 2 is mediated by apoptosis.