Detailed phytochemical and antioxidant profiling of extracts obtained from flower buds of Magnolia×soulangeana Soul.-Bod. var. ‘Lennei’

Magnolia×soulangeana Soul.-Bod. var. ‘Lennei’ (MSL) is known as one of the most famous ornamental species grown in many botanical gardens in Europe. In the present study, in-depth phytochemical profiling of aqueous-ethanolic extracts obtained from MSL flower buds, previously collected at the UMCS Botanical Garden (Lublin, Poland), was performed using coupled chromatographic (RP-LC), spectroscopic (PDA) and mass spectrometric (QTOF/MS-MS) techniques. At the same time, the total phenolic content (TPC) and antiradical capacity of MSL extracts were evaluated using Folin-Ciocalteu and DPPH assays, respectively. To ensure the highest recovery of phenolic compounds from MSL flower buds, ultrasound-assisted extraction (UAE) was used with optimised extraction parameters (temperature, extraction time, composition of aqueous-ethanol extractants and solvent-to-solid ratio), controlled by a response surface methodology (RSM) protocol. As a result, the highest polyphenolic content of MSL extracts were determined for preparations obtained using an extraction solvent (ethanol) in the concentration range of 63 – 82% (optimum 66.82%, v/v), solvent/herbal substance ratio>45 mL/g (optimum 46.82 mL/g), and UAE time of

55.2 min. Detailed phytochemical LC-MS studies revealed the presence of significant amounts of polyphenols (with different types of molecular structure) in MSL flower buds, namely hydroxybenzoic (protocatechuic, vanillic, p-hydroxybenzoic) and hydroxycinnamic (chlorogenic) acids, phenylethanoids (acteoside, echinacoside, yulanoside B), flavonoids (rutoside, quercitrin, isoquercitrin, nicotiflorin, isorhamnetin 3-O-glucoside) and lignans (magnolin and fargesin derivatives). Simultaneous phytochemical and biological profiling confirmed that MSL flower buds could serve as a potential source of bioactive polyphenolic antioxidants with promising therapeutic effects.

Publication History

Article published online:
16 November 2023