Study On Metabolic Dynamic Of Camptothecin And 10-Hydroxcamptothecin Regulated By Development And Environment

Camptotheca acuminata is a tree unique to China, producing terpenoid indole alkaloid (TIA) 10-Hydroxycamptothecin (HCPT) and camptothecin (CPT), which possess strong anti-cancer bioactivity. The dynamics of HCPT and CPT during seed maturation, seed germination, post-germinative development and daily growth were measured by HPLC (High Performance Liquid Chromatography). This paper provides some evidence for presenting the theory that each characteristic of HCPT and CPT accumulation is under developmental regulation and then attempt to elucidate the metabolic relationships between them. The results revealed that HCPT accumulates particularly in young tissues and organs and is relatively unstable, while the distribution of CPT is more ubiquitous and stable. Their different distribution properties suggest that HCPT and CPT were differentially regulated during development and HCPT is the special defensive strategy for Camptotheca. CPT, however, is a universal tactic.Plants interact with their environment by producing a diverse array of secondary metabolites, one of which is alkaloid. In this paper, alkaloid, including Camptothecin (CPT) and 10-hydroxycamptothecin (HCPT), malondialdehyde (MDA) and chlorophyll contents were measured during heat shock in Camptotheca acuminate seedlings. Responses of different tissues, including young leaves, old leaves, shoots and barks, to heat shock were examined in alkaloid changes. CPT and HCPT concentrations reached to their peak values separately at 38癈 and 40癈 , which were before the lethal heat-shock temperature indicated by MDA and chlorophyll, and their great changes took place in young leaves. These results indicated that CPT and HCPT are involved in the C. acuminata resistance against heat shock from its environment. Furthermore, plant rigidly observed the cost-benefit principle and mobilized and allocated limited alkaloid sources to young and reproductive tissues preferentially. In addition, HCPT displayed well-regulated changes during incubation at sublethal temperature and this indicated that HCPT may play a more positive defensive role in enhance of plant thermotolerance than CPT does.