Antiproliferative labdane diterpenes from the rhizomes of Hedychium flavescens Carey ex Roscoe.

Antiproliferative activity was confirmed in the various extracts of rhizomes of Hedychium flavescens (Zingiberaceae). The phytochemical investigation of the rhizomes of Hedychium flavescens led to the isolation of four labdane diterpenes. Their structures were established as coronarin E (1), C-14 epimers of isocoronarin D (2), C-15 epimers of coronarin D methyl ether (3) and isocoronarin D (4). The structure of the compounds was identified based on spectroscopic analysis and on comparison with literature reports. All these compounds were assessed for their in vitro cytotoxicity against human lung adenocarcinoma (A549) cell line and showed significant cytotoxicity as reflected in IC50 value, that is, 0.52, 0.59, 0.68 and 1.22 μM compared with the control doxorubicin (IC50 0.92 μM). Moreover, all the compounds were nontoxic towards the normal lung fibroblast (WI-38) cells. The chemo-profiling and cytotoxicity study of Hedychium flavescens is reported for the first time.