Changes in the contents of four active diterpenoids at different growth stages in Andrographis paniculata (Burm.f.) Nees (Chuanxinlian)

BACKGROUND: The therapeutic activities of Andrographis paniculata are attributed to four major active diterpenoids: andrographolide (AP(1)), 14-deoxy-11,12-didehydroandrographolide (AP(3)), neoandrographolide (AP(4)), and 14-deoxyandrographolide (AP(6)). This study aims to quantify the four active diterpenoids in various plant organs of A. paniculata at different growth stages in greenhouse and field experiments, with a developed HPLC-diode array detector (HPLC-DAD) method for simultaneous determination of these diterpenoids. METHODS: Plants were grown in greenhouse and in field conditions, harvested at different growth stages, and separated into different organs for determination of the four active diterpenoids by an HPLC-DAD method. RESULTS: The most abundant diterpenoid was AP(6) between seedling and vegetative stages in the greenhouse experiment (13.38 to 23.71 mg/g in 2006 and 10.67 to 24.54 mg/g in 2007). High levels of AP(6) were also detected in leaves at the transfer stage in the greenhouse experiment (36.05 ± 0.69 mg/g) and field experiment (30.59 ± 1.39 mg/g). The levels of AP(6) then decreased as plants matured. The highest content of AP(4) was in cotyledons (16.65 ± 4.48 mg/g) at the transfer stage. The highest contents of AP(1) were detected in leaves at seed-forming stage in greenhouse experiment (24.72 ± 1.89 mg/g) and vegetative stage in field experiment (43.16 ± 0.92 mg/g). Flowers of A. paniculata contained high levels of AP(1) (21.42 ± 3.74 mg/g). AP(3) and AP(4) were at low levels in leaves at all growth stages. CONCLUSION: In A. paniculata, AP(6) was at the highest level in leaves at transfer stage in both greenhouse and field experiments. AP(1) was at the highest level in leaves at vegetative stage and seed-forming stage in field and greenhouse experiments, respectively. The contents of AP(3) and AP(4) in leaves were low at all growth stages.