Changes in growth characteristics and secondary metabolites in Sinopodophyllum hexandrum with increasing age

Abstract

Sinopodophyllum hexandrum is a perennial rhizomatous herb that produces the highly valued lignin podophyllotoxin (PPT). Although the effects of environmental factors on growth and secondary metabolites accumulation have been revealed, the changes with increasing plant age have not yet been conducted. Here, growth characteristics, contents of lignans and flavonoids, and expression levels of key genes in 2- to 9-year-old plants were systematically examined. The growth parameters significantly increased, and there were three distinctly morphological variants with single, two, and three leaves with increasing plant age. The accumulation of two lignans PPT and 4'-demethylepipodophyllotoxin (4'-DMEP), three target flavonoids, total flavonoids and phenolic, as well as in vitro antioxidant capacity maximized at 5–6 years. The expression levels of 8 key genes participating in lignan and flavonoid biosynthesis were up-regulated with increasing plant age. The findings provide the compelling evidence to guide sustainable cultivation and collection of S. hexandrum.