Effect of Shading on Development, Yield and Quality of Bastard Balm Herb (Melittis melissophyllum L.)

Abstract

The aim of the study was to assess the effects of Melittis melissophyllum shading on its development and accumulation of phenolics. Their content (verbascoside, apiin, luteolin-7-O-glucoside, coumarin, 3,4-dihydroxycoumarin, o-coumaric acid 2-O-glucoside as well as o-coumaric, p-coumaric, chlorogenic, caffeic, ferulic and cichoric acid) was determined in the herb using HPLC-DAD. The results showed that the content of abovementioned flavonoids and phenolic acids was highest in plants grown under full sunlight. On the other hand, a higher content of coumarin was observed in shaded plants, especially after the seed-setting stage. A similar tendency was noted for the amount of chlorophyll a and b. The content of hydrogen peroxide and malondialdehyde, the activity of polyphenol oxidase and catalase and the antioxidant capacity of plant extracts (measured using DPPH, ABTS and FRAP assays) were found to be the highest in the plants grown in full sunlight. However, the plants grown in moderate (30%) shade were found to thrive best.

Developmental and chemical characteristics of Melittis melissophyllum L. in limited access of sunlight

“…Although considered to induce liver toxicity, it is present in many plant products used on a daily basis, including cinnamon, tea, or lavender. In the previous investigation on bastard balm it was shown that the accumulation of coumarin in bastard balm herb may be related with light conditions during its growth [5]. It was confirmed in this study.…”

“…In this experiment, they were detected in higher quantities at the generative stage, which may confirm their protective role during this crucial phase, determining the possibility to obtain progeny plants. Higher content of some specific flavonoids and phenolic acids in plants grown at full sunlight compared to shaded ones was observed in previous research on bastard balm [5]. One of the most important groups of secondary metabolites in bastard balm herb are coumarins with coumarin used as a quality marker.…”

“…Its leaves contain about 0.09% of essential oil with more than 100 compounds identified so far. Among these, the dominants are 1-octen-3-ol, n-hexadecanoic acid, phytol, ledol, α-pinene, coumarin, sabinene, germacrene D [5,6]. One of the most important compounds in the essential oil is 1-octen-3-ol, responsible for specific mushroom-like odour, potentially desirable in food industry [7].…”

Chemical Diversity of Bastard Balm (Melittis melisophyllum L.) as Affected by Plant Development

“…This was well-documented in our previous investigations on M. melissopyllum. The plants grown in moderate (30%) shade were found to thrive best; however, the content of coumarin in the herb was the highest in deep (50%) shade, compared to full sunlight and 30% shade [21]. Values marked in rows with different letters differ at p < 0.05.…”

“…Separations were achieved by using a C18 reverse-phase Kinetex ™ column, 2.6 µm, 100 mm × 4.60 mm, with a porous outer layer on solid silica core particles (Phenomenex ® , Torrance, CA, USA). Validation parameters has already been described in detail by Szymborska-Sandhu et al [21]. Quantification of the analyzed compounds was performed with analytical wavelength appropriate for each compound:…”