Production of tumour-inhibitory lignans in callus cultures of Podophyllum hexandrum.

Callus cultures have been established from root explants of aseptically-grown Podophyllum hexandrum seedlings. A fully defined medium based on Gamborg's B5 salts supplemented with 2/4-dichlorophenoxyacetic acid, gibberellic acid and 6-benzylaminopurine was effective for both initiation and sustained growth of callus tissue. Cultures produced anticancer lignans podophyllotoxin, 4'-demethylpodophyllotoxin and podophyllotoxin 4-O-glucoside at levels similar to those found in the expiant material as assayed by high performance liquid chromatography. The relative proportions of podophyllotoxin and 4'-demethyl-podophyllotoxin were markedly influenced by the presence of plant growth regulators. Particularly high levels of podophyllotoxin were associated with growth regulator induced tissue differentiation.