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.) Matanzima Yonela1, Laubscher Charles P.1, Mabusela Wilfred T.2, Nchu Felix1,* 1Department of Horticultural Sciences, Faculty of Applied Sciences, Cape Peninsula University of Technology, P.O Box 1906, Bellville7535, South Africa 2Department of Chemistry and South African Herbal Sciences and Medicines Institute, University of the Western Cape, Private Bag X17, Bellville7535, South Africa *Corresponding author e-mail: felixnchu@gmail.com
Online published on 2 April, 2021. 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 3,5dicaffeoylquinic 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. Top Keywords Cultivation of medicinal plants, Total activity, Secondary metabolite, Antifungal activity. Top |