UHPLC-ESI-ORBITRAP-MS analysis of the native Mapuche medicinal plant palo negro (Leptocarpha rivularis DC. – Asteraceae) and evaluation of its antioxidant and cholinesterase inhibitory properties

Abstract

UHPLC/ESI/MS identification of organic compounds is the first step in the majority of screening techniques for the characterization of biologically active metabolites in natural sources. This paper describes a method for the fast identification and characterisation of secondary metabolites in Leptocarpha rivularis DC. (Palo negro) extracts by HPLC/UV (DAD)–Mass Spectrometry (HPLC/MS). The plant is used for the treatment of several diseases since pre-hispanic Mapuche times. Thirty-seven compounds were detected in the aqueous edible extract for the first time including 4 sesquiterpenes, 10 flavonoids, 9 oxylipins, 2 organic acids, and 11 phenolic acids. In addition, phenolic content antioxidant and cholinesterase inhibitory activities were measured for the first time using the edible infusion. The total polyphenol content of the infusion was 230.76 ± 2.5 mmol GAE/kg dry weight, while the antioxidant activity was 176.51 ± 28.84; 195.28 ± 4.83; and 223.92 ± 2.95 mmol TE/kg dry weight, for the DPPH, ABTS, and FRAP assays, respectively. The cholinesterase inhibitory activity was 7.38 ± 0.03 and 5.74 ± 0.06 mmol GALAE/kg, for the inhibition of acetylcholinesterase AChE and BChE, respectively, showing that this plant is a candidate for the isolation of compounds that can be useful for the treatment of neurodegenerative diseases. Furthermore, this plant could serve also as a raw material for the production of dietary supplements, due to its content of polyphenolic compounds.

Recent applications of high resolution mass spectrometry for the characterization of plant natural products

“…Nardin et al [54] demonstrated the versatility of Q-Orbitrap systems to perform accurate quantitation of 35 alkaloids and untargeted screening of further 305 alkaloids in herbal extracts. On-line coupling of UV detectors with Q-Orbitrap were also reported in characterization [55], metabolic [56] and dereplication [57] studies, demonstrating that (U)HPLC-DAD-Q-Orbitrap-MS hyphenation can effectively detect and quantify small organic compounds such as phenolics and sesquiterpene lactones. Móricz et al [58] reported the benefit of highperformance thin-layer chromatography (HPTLC)-hyphenations in the discovery and characterization of active natural compounds.…”

Antihyperlipidemic and Antioxidant Capacities, Nutritional Analysis and UHPLC-PDA-MS Characterization of Cocona Fruits (Solanum sessiliflorum Dunal) from the Peruvian Amazon

“…The ABTS assay was performed by bleaching of the cationic radical ABTS •+ as described by [8]. For the preparation of the radical ABTS •+ 2.5 mL of the 7 mM ABTS solution, it was mixed with 2.5 mL of 2.45 μM sodium persulfate for 12 hours in the dark at 4 O C. Then, the resulting solution was diluted with absolute ethanol until an initial absorbance of approximately 0.70 ± 0.03 was obtained at 734 nm.…”

Phytochemical Profiling and Assessment of Anticancer Activity of Leptocarpha rivularis Extracts Obtained from In Vitro Cultures

“…It grows mainly in the southern part of Chile (between VII and X regions) [1], and it has been known and used for centuries as folk medicine by the Mapuche people [2]. Previous phytochemical studies of L. rivularis have shown that extracts obtained from leaves, bark, and flowers exhibit antioxidant, hypoglycemic, and anticancer effects [3][4][5][6][7]. These biological activities have been attributed to the presence of sesquiterpene lactones, i.e., leptocarpine (LTC) as the major component and small amounts of rivularin and the 17,18-dihydroleptocarpin derivative [8][9][10][11].…”