Podophyllotoxin content in leaves of eastern red cedar (Juniperus virginiana)

Eastern red cedar (Juniperus virginiana L. Cupressaceae) occurs naturally throughout eastern North America and has been identified as a source of podophyllotoxin. Podophyllotoxin is used to manufacture drugs for treatment of cancer, rheumatoid arthritis, genital warts, psoriasis, and multiple sclerosis. Leaf material was collected from Juniperus plants located in northern Mississippi once a month from April 2001 to March 2002. The objective of the survey was to examine variations in podophyllotoxin content due to sampling date and plant type. Samples of 100 g of fresh leaf tissue were collected from juvenile, immature, mature male, and mature female plants and then dried, ground, extracted in chloroform, and analyzed with HPLC to measure podophyllotoxin content. Leaf tissue was harvested from the same immature and mature plants each sampling date. Average podophyllotoxin content of juvenile plants was 0.60 mg(.)g(-1) compared to approximately 1.45 mg(.)g(-1) in immature and mature plant types. Reproductive status, male or female, did not affect podophyllotoxin content. Sampling date significantly affected podophyllotoxin content. Plants harvested in January and April exhibited the greatest podophyllo-toxin content (1.56 and 1.45 mg(.)g(-1), respectively) and plants, harvested in February and June exhibited the lowest content (1.06 and 1.08 mg(.)g(-1), respectively). Though differences due to sampling date were statistically significant, there appeared to be no obvious pattern or trend. There was no significant interaction between plant type and sampling date. These results indicate that juvenile leaf tissue should be avoided due to its lower podophyllotoxin content compared to that of mature leaf tissue. These results also indicate that podophyllotoxin content of Eastern red cedar can vary as much as 50 % over time, ranging from a low of 1.06 to a high of 1.56 mg(.)g(-1).