Effects of varying levels of nitrogen on plant growth, anti-Fusarium oxysporum activity and 3,5-dicaffeoylquinic acid concentration of extracts from hydroponically cultivated Helichrysum cymosum (L.)

Abstract

Experiments were conducted to assess the effects of varied nitrogen (N) concentrations on plant growth, tissue nutrient content, and antimicrobial activity of acetone extract of aerial parts of Helichrysum cymosum. Six weeks old rooted cuttings were treated with 52.5, 105.0, 210.0, and 420.0 mg N/L by varying the nutrient N level in plant growth medium. Plant growth parameters, leaf tissue nutrient content, anti-Fusarium oxysporum activity, and a well-known bioactive secondary metabolite (3,5-dicaffeoylquinic acid) concentration in the plant extracts were analysed. Leaf number increased with increasing N level, while height increase was highest at the lowest N treatment. Tissue analysis of N content and LC-MS analysis of the acetone extracts of aerial parts indicated that lower N treatment corresponded to lower tissue N and higher accumulation of 3,5- dicaffeoylquinic acid in the extracts, respectively. In conclusion, lower nutrient N level significantly correlated with increased antimicrobial activity and yield of the targeted compound of the crude acetone extract of H. cymosum. This study suggests that nitrogen fertilization may be manipulated to optimize bioactivities of crude extracts of medicinal plants.