Bioactive constituents of Indigofera spicata.

Four new flavanones, designated as (+)-5″-deacetylpurpurin (1), (+)-5-methoxypurpurin (2), (2S)-2,3-dihydrotephroglabrin (3), and (2S)-2,3-dihydrotephroapollin C (4), together with two known flavanones (5 and 6), three known rotenoids (7-9), and one known chalcone (10) were isolated from a chloroform-soluble partition of a methanol extract from the combined flowers, fruits, leaves, and twigs of Indigofera spicata, collected in Vietnam. The compounds were obtained by bioactivity-guided isolation using the HT-29 human colon cancer, 697 human acute lymphoblastic leukemia, and Raji human Burkitt's lymphoma cell lines. The structures of 1-4 were established by extensive 1D- and 2D-NMR experiments, and the absolute configurations were determined by the measurement of specific rotations and CD spectra. The cytotoxic activities of the isolated compounds were tested against the HT-29, 697, Raji, and CCD-112CoN human normal colon cells. Also, the quinone reductase induction activities of the isolates were determined using the Hepa 1c1c7 murine hepatoma cell line. In addition, cis-(6aß,12aß)-hydroxyrotenone (7) was evaluated in an in vivo hollow fiber bioassay using HT-29, MCF-7 human breast cancer, and MDA-MB-435 human melanoma cells.

Potentiating effect of the flavonolignan (-)-hydnocarpin in combination with vincristine in a sensitive and P-gp-expressing acute lymphoblastic leukemia cell line.

The potentiating action of the flavonolignan, (-)-hydnocarpin, in combination with vincristine was evaluated in the 697 acute lymphoblastic leukemia cell line and a P-gp-expressing variant, 697-R. Vincristine at 3 nM caused nearly complete growth inhibition in 697 cells versus a 17% growth inhibition in 697-R cells. When combined with (-)-hydnocarpin at concentrations of 10 and 5 µM, vincristine-mediated growth inhibition in the 697-R cells increased significantly over the sum of the individual agents to 72% (p ≤ 0.0001) and 41% (p = 0.0256), respectively. Vincristine at 1.5 nM (66% growth inhibition) and 0.75 nM (39% growth inhibition) combined with (-)-hydnocarpin at 10 µM (42% growth inhibition) in the 697 cells caused a significant increase in growth inhibition to 83% (p = 0.03) and to 61% (p < 0.0001), respectively, when compared to vincristine treatment as a single agent. To investigate the mechanism for the vincristine re-sensitization caused by (-)-hydnocarpin, the P-gp inhibitory effect of (-)-hydnocarpin was evaluated.

Caeruleanone A, a rotenoid with a new arrangement of the D-ring from the fruits of Millettia caerulea.

Caeruleanone A (1), a novel rotenoid with an unprecedented arrangement of the D-ring, was isolated with another two new analogues, caeruleanones B (2) and C (3), together with 11 known rotenoids from the fruits of Millettia caerulea. The structures of the new compounds were determined by spectroscopic data analysis, with that of 1 being confirmed by single-crystal X-ray diffraction. Compounds 2 and 3 displayed potent mitochondrial transmembrane potential inhibitory and quinone reductase induction activities.