Rotenoids and isoflavones from the leaf and pod extracts of Millettia brandisiana Kurz

Phytochemical investigations of the leaf and pod extracts of Millettia brandisiana Kurz led to the isolation and identification of four previously undescribed rotenoids, (–)-(6aS,12aS)-millettiabrandisins A–C and (–)-(6aS,12aS)-6-deoxyclitoriacetal, two previously undescribed isoflavones, millettiabrandisins D and E, and 20 known compounds. The structures of previously undescribed compounds were determined on the basis of NMR and MS data. The absolute configurations of (–)-(6aS,12aS)-millettiabrandisins A–C were determined from the comparison of their experimental and calculated ECD spectra. (–)-(6aR,12aR)-12a-Hydroxy-α-toxicarol was also confirmed by X-ray crystallographic data. Some isolated compounds were evaluated for their cytotoxicity against three cancer cell lines, including lung cancer (A549), colorectal cancer (SW480), and leukemic cells (K562). Of these, α-toxicarol displayed the best cytotoxicity against lung cancer (A549) and leukemic cells (K562) with the IC50 values of 104.4 and 67.5 μM, respectively. 6″,6″-Dimethylchromene-[2″,3″:7,8]-flavone showed the highest cytotoxicity against colorectal cancer (SW480) with an IC50 value of 97.2 μM.