Profiling of polyphenols and sesquiterpenoids using different extraction methods in Muscari turcicum, an endemic plant from Turkey

Abstract

Muscari turcicum, endemic to south Anatolia, Turkey, represents an unexplored crop plant, with potential therapeutic uses related to its phytochemical composition. In this work, the in vitro antioxidant and enzyme inhibitory activity of flower, leaf and bulb extracts, obtained using different extraction methods were evaluated. A comprehensive polyphenolic and sesquiterpene lactones profiling of the different extracts was also undertaken. For this purpose, UHPLC-QTOF mass spectrometry allowed us to putatively annotate 280 phytochemical compounds of which 162 were polyphenols and 118 were sesquiterpene lactones. The most abundant polyphenols were flavonoids (77 compounds), phenolic acids (34 compounds), and low molecular weight phenols (38 compounds). Muscari turcicum leaf methanol extract possessed the highest concentrations of low-molecular-weight phenolics, phenolic acids, and sesquiterpene lactones (20.61, 7.00, and 3.44 mg standard equivalent/g, respectively). The water extract of M. turcicum flower obtained by infusion showed prominent reducing (120.52 mg Trolox equivalent [TE]/g mg TE/g for both CUPRAC and FRAP) and radical scavenging potential (91.39 mg TE/g, for DPPH assay). Besides, M. turcicum flower methanol extract (13.44 mg EDTA equivalent/g) showed the highest metal chelating activity. Interestingly, methanol extracts obtained by Soxhlet extraction and maceration actively inhibited tyrosinase (129.36 mg kojic acid equivalent/g) and cholinesterases (5.15 mg galantamine equivalent [GALAE]/g and 6.16 mg GALAE/g, for acetyl and butyryl cholinesterase) respectively. Strong correlations (p < 0.01) were observed between polyphenols/sesquiterpenoids and observed biological activities. Scientific evidences presented in this study has provided baseline data for bioprospection of novel pharmaceutical/cosmetic candidates from Muscari turcicum, thus supporting its therapeutic exploitation