Phenanthrene derivatives from roots and rhizomes of Asarum heterotropoides var. mandshuricum.

Five new phenanthrene derivatives: 9-ethoxy-7-methoxy-aristololactam IV (1) , norcepharadione A N - β - d -glucopyranoside (2) , aristololactamoside I (3) , aristololactamoside II (4) and aristothiolactoside (5) together with eleven known phenanthrene derivatives ( 6 – 16 ) were isolated from the ethanol extract of the roots and rhizomes of Asarum heterotropoides var. mandshuricum . The aristololactams with substitution of ethoxy at C-9 position ( 1 , 9 , and 10 ) and the sulfur-containing phenanthrene derivative ( 5 ) were reported in the genus Asarum for the first time. Furthermore, six phenanthrene glucoside derivatives ( 2 – 5 , 13 and 14 ) were also found in this genus for the first time and compounds 7 and 9 – 15 were isolated from the genus Asarum for the first time. Six of them ( 1 , 2 , 9 , 10 , 13 and 14 ) were submitted to cytotoxicity test against human renal proximal tubular epithelial cell lines (HK-2) using MTT and LDH assays. Compounds 1 and 10 showed significant cytotoxic activity against HK-2 cell lines with IC 50 values of 18.18 and 20.44 μmol/L in MTT assay and 84.36 and 35.06 μmol/L in LDH assay, respectively. Compound 9 showed moderate cytotoxicity in MTT assay with IC 50 values of 95.60 μmol/L, but no cytotoxicity in LDH assay. Compounds 2 , 13 and 14 showed cytotoxic effect in neither MTT assay nor LDH assay. Considering the other nephrotoxic phenanthrene derivatives ( 6 , 8 , 12 , 15 and 16 ) previously tested, the results implied the potency of renal toxicity of this herb used as a medicine. [ABSTRACT FROM AUTHOR]