UHPLC-MS Chemical Fingerprinting and Antioxidant, Antiproliferative, and Enzyme Inhibition Potential of Gaultheria pumila Berries

Gaultheria pumila (Ericaceae) (known as Chaura or Mutilla) is a Chilean native small shrub that produces berry fruits consumed by local Mapuche people. In this study, the chemical fingerprinting and antioxidant, enzyme inhibition, and antiproliferative activities of the berries were investigated for the first time. Thirty-six metabolites were identified in the fruits by ultra-high performance liquid chromatography-photodiode array detection, hyphenated with Orbitrap mass spectrometry analysis (UHPLC-DAD-Orbitrap-MS). Metabolites, included anthocyanins, phenolic acids, flavonoids, iridoids, diterpenes, and fatty acids. Moderate inhibitory activities against acetylcholinesterase (7.7 ± 0.3 µg/mL), butyrylcholinesterase (34.5 ± 0.5 µg/mL), and tyrosinase (3.3 ± 0.2 µg/mL) enzymes were found. Moreover, selected major compounds were subjected to docking assays in light of their experimental inhibition. Results indicated that hydrogen bonding, π–π interaction, and a salt bridge interaction contributed significantly. Gaultheria pumila berries showed a total phenolic content of 189.2 ± 0.2 mg of gallic acid equivalents/g, total flavonoid content of 51.8 ± 0.1 mg quercetin equivalents/g, and total anthocyanin content of 47.3 ± 0.2 mg of cianydin-3-glucoside equivalents/g. Antioxidant activity was assessed using DPPH (92.8 ± 0.1 µg/mL), FRAP (134.1 ± 0.1 μmol Trolox equivalents/g), and ORAC (4251.6 ± 16.9 μmol Trolox equivalents/g) assays. Conversely, Gaultheria pumila showed a scarce antiproliferative potential against several solid human cancer cells. Our findings suggest that Gaultheria pumila berries have several bioactive metabolites with inhibitory effects against acetylcholinesterase, butyrylcholinesterase, and tyrosinase, and have the potential for use in food supplements.

In vitro propagation of Gaultheria pumila (L.f.) D.J. Middleton (Ericaceae), a Chilean native berry with commercial potential

A micropropagation protocol for G. pumila was developed. Young shoots were collected during the growing season (October to December 2016) from a wild population in the Villarrica Volcano area in the Araucanía Region of Chile. Nodal segments were used for in vitro initiation after testing several disinfection treatments with different concentrations of sodium hypochlorite. Disinfected explants were placed onto 100% WPM basal medium (WPM100) supplemented with a range of concentrations of 2-iP (2-isopentenyladenine) to evaluate the best regeneration media during in vitro culture. Disinfection with 1% sodium hypochlorite for 40 minutes, followed by a second disinfection with 2% sodium hypochlorite for 25 minutes, and cultivation on MS basal medium supplemented with 2 mg L-1 2-iP gave the highest efficiency of disinfected plants. In the propagation stage, the highest multiplication rates were obtained when 1 mg L-1 zeatin was added to the basal WPM100 medium. In vitro rooting and preacclimation were better when elongated plants were cultivated on WPM100 supplemented with 3 mg L-1 naphthalene acetic acid. This in vitro protocol could be used to propagate genotypes of this Chilean native species and is also an important tool toward its domestication and commercial use.