Callitris intratropica R.T. Baker & H.G. Smith as a Novel Rich Source of Deoxypodophyllotoxin

The essential oil of Callitris intratropica is composed to a considerable proportion of rather unique lactones like callitrin (I), callitrisin (II) and columellarin (III) (Fig. 1) [1-7]. During the investigation of the volatiles obtained by hydrodistillation of the wood of this Cupressaceae species [8] we noticed that the oil yield increases with distillation time while the oil composition is shifted more and more towards the high boiling components. To find the reason for this behavior some wood was extracted in a Soxhlet apparatus and the resulting red-brown resinous oil analyzed by GC-MS-FID on a short GC column. The lignans deoxypodorhizon (IV) and deoxypodophyllotoxin (V) [9 -11] were disclosed and present in rather large amounts. Since the wood is available in large quantities this finding points out a new rich source [12 - 14] of these potent bioactive lignans.