Accumulation of L-DOPA in various organs of faba bean and influence of drought, nitrogen stress, and processing methods on L-DOPA yield

摘要

Faba bean(Vicia faba L.)has been identified as a rich source of L-DOPA,which is used in treating Parkinson's disease.Biosynthesis and accumulation of active substances such as L-DOPA in plant tissues may interact with growing conditions and processing methods.Accumulation trends of L-DOPA in various faba bean organs and the effect of drought stress and N fertilization on L-DOPA content were studied in a field and two greenhouse experiments.The influence of various processing methods on L-DOPA content of faba bean tissues was evaluated.The highest L-DOPA content was detected in fresh leaves(22.4 mg g^(-1))followed by flowers,young pods,mature seeds,and roots.Regardless of processing method,L-DOPA concentration in faba bean tissues was significantly reduced when tissues were boiled or dried.Among various methods of processing,freezing had the lowest detrimental effect,reducing L-DOPA concentrations by 24.1%and 21.1%in leaves and seeds,respectively.Drought stress elevated L-DOPA concentration,and maximum L-DOPA(23.3 mg g^(-1)of biomass)was extracted from plants grown under severe drought stress.However,L-DOPA yield(L-DOPA concentration×biomass)was compromised,owing to the adverse influence of drought stress on dry matter production.No significant difference in L-DOPA concentration was detected among various N application rates.