Laxiflorol A, the first example of 7,8:15,16-di-seco-15-nor-21-homo-ent-kauranoid from Isodon eriocalyx var. laxiflora

Laxiflorol A (1), an unprecedented 7,8:15,16-di-seco-15-nor-21-homo-ent-kauranoid, and its precursor analogue, laxiflorol B (2), were isolated from the leaves of Isodon eriocalyx var. laxiflora. The absolute configuration of 1 was determined by spectral methods and quantum chemical calculations. Compound 2 exhibited weak cytotoxicity.