Yield and Chemical Composition of Raw Material from Meadow Arnica (Arnica chamissonis Less.) Depending on Soil Conditions and Nitrogen Fertilization

Abstract

Considering the global tendency towards using valuable secondary metabolites of plant origin, there is a need to optimize the cultivation of herbal plants, e.g., the meadow arnica (A. chamissonis Less.). The inflorescences of this species (Arnicae anthodium) have a similar chemical composition and pharmacological activity to that in the mountain arnica (Arnica montana L.), and can be cultivated more easily than the mountain arnica. Therefore this study assesses soil and fertilization effects on the flower head yield and concentrations of active substances (sesquiterpene lactones, flavonoids, and essential oil) with great importance for application in the pharmaceutical and cosmetic industries. A field experiment was carried out during 2017–2019 on two types of soil (sandy and loamy soils) differing in the pH values, organic matter content, and the P, K, and Mg levels. Five levels of nitrogen fertilization were applied in both soil variants: 0, 30, 60, 90, and 120 kg N∙ha−1. The study showed that both the soil type and the nitrogen fertilization had a positive impact on the raw material yield and the content and yield of the main active substances. The cultivation of arnica in the loamy soil was more favorable—it provided a higher flower head yield, higher levels of sesquiterpene lactones, flavonoids, and essential oils, and consequently, a higher yield of these metabolites. High flower head yields were achieved at doses of 60 and 90 kg N∙ha−1. The content of sesquiterpene lactones and essential oils increased in the consecutive study years along with the increase in nitrogen doses. The highest content of flavonoids was detected in flower heads obtained from three-year-old plants fertilized with 60 kg N∙ha−1. High yields of sesquiterpene lactones and essential oils were obtained at doses of 90–120 kg N∙ha−1, whereas the fertilization with 60–90 N∙ha−1 ensured a high yield of flavonoids. The yields of sesquiterpene lactones and essential oil did not depend on their concentration but correlated with the increase in the yield of flower heads of plants cultivated in both sandy and loamy soil variants. In turn, the yield of flavonoids was influenced by both their concentration and the flower head yield. The flower head yield, the content of sesquiterpene lactones, flavonoids, and essential oils, and the yields of metabolites presented in this study indicate favorable climatic conditions for the cultivation of A. chamissonis in Central and Eastern Poland. This proves that a wide range of pharmacologically active substances can be produced in this region of Europe.

Nitrogen Fertilization and Solvents as Factors Modifying the Antioxidant and Anticancer Potential of Arnica montana L. Flower Head Extracts

“…There are no available literature reports on the NF effect on the content of SL in the mountain arnica. A similar plant response to that described in the present study was reported by Olesińska et al [ 45 ], who showed an increase in the content of SL with a simultaneous increase in nitrogen doses to 60 and 90 kg N ha −1 in meadow arnica flower heads.…”

“…There are no available literature reports on the NF effect on the content of flavonoids in the mountain arnica. Similar findings of the NF effect on the flavonoid content have been described in a study of Arnica chamissonis , where 60 kg N ha −1 was the most favorable nitrogen dose [ 45 ], and Athrixia phylicoides DC., where 75 kg N ha −1 was the most favorable nitrogen dose stimulating the synthesis of flavonoid compounds, with the highest increase in quercetin content [ 61 ]. In the cited studies, a further increase in the applied nitrogen doses led to a significant decrease in the concentration of flavonoids, as in the case of the mountain arnica.…”

“…The role of nitrogen in the synthesis of SL has not been elucidated in A. montana to date. Differences in plant response to nitrogen have been demonstrated in the meadow arnica by Olesińska et al [ 45 ] and in other plants represent the family Asteraceae [ 58 , 59 ].…”

“…Literature data indicate that NF affects the EO content in various herbal raw materials [ 63 , 64 , 65 , 66 ]. A beneficial effect of NF was demonstrated also in the case of meadow arnica [ 45 ]. As shown in literature data, the EO content in Arnicae flos is significantly dependent on the maturity of flower heads [ 13 ], foliar boron application [ 17 ], and plant development phases [ 53 , 62 ].…”

“…It is involved directly or indirectly in the production of secondary metabolites. In the case of medicinal and aromatic plants, it can also influence the content and chemical composition of secondary metabolites [ 43 , 44 , 45 , 46 ]. Although A. montana has long been cultivated mainly for production of flower heads and many studies have been conducted to characterize this raw material, knowledge of the antioxidant and biological activity of water extracts of the species is still insufficient, as mainly methanol, ethanol, and acetone have been used as solvents [ 19 , 23 , 39 , 40 , 42 , 47 , 48 ].…”