Diterpenes and a flavone from Leucas neufliseana

Three labdane-type diterpenes; 3-oxo-marrubiin and a mixture of two related C-15 epimeric diterpenes based on 9 alpha,13 alpha,15,16-bisepoxy-15-hydroxy-3-oxo-labdan-6 beta,19-olide, in addition to the acylated flavone apigenin 7-O-[6 ''-O-(p-hydroxy-trans-cinnamoyl)glucoside] were isolated and identified from the aerial parts of Leucas neufliseana. Their structures were established through physical and chemical methods in addition to standard spectroscopic techniques. This is the first report of the isolation of the two epimeric diterpenes from a natural source.