文摘
The effect of five lignans, epi-aschantin, epi-magnolin, epi-yangambin, deoxypodophyllotoxin and yatein, isolated from Hernandia nymphaeifolia on Ca2+ signaling in Madin–Darby canine kidney cells was examined using fura-2 as a Ca2+ indicator. These lignans at concentrations between 10 and 100 μM increased [Ca2+]i in a concentration-dependent manner. Removal of extracellular Ca2+ abolished the Ca2+ signals evoked by 50 μM of the lignans. La3+(50 μM) abolished the Ca2+ signals induced by 100 μM of epi-aschantin, epi-magnolin and epi-yangambin, and 20 μM deoxypodophyllotoxin, but inhibited by 60 % 50 μM yatein-induced responses. All five lignans (50–100 μM) inhibited by 42–65 % thapsigargin-induced capacitative Ca2+ entry, and inhibited by 23–61 % thapsigargin-induced intracellular Ca2+ release. Epi-yangambin (100 μM), epi-magnolin (100 μM), and epi-aschantin (100 μM) inhibited by 8–38 % 10 μM ATP-induced Ca2+ release. Trypan blue exclusion revealed that incubation with deoxypodophyllotoxin or yatein (but not the other lignans) decreased cell viability in a concentration-dependent manner. Together, the results suggest that, in renal tubular cells, these lignans exert multiple actions on Ca2+ signaling. They caused Ca2+ influx but reduced thapsigargin-induced capacitative Ca2+ entry and also thapsigargin- and ATP-induced Ca2+ release. Additionally, deoxypodophyllotoxin and yatein may be cytotoxic.