Antioxidant properties of lingonberry (Vaccinium vitis-idaea L.) plants

Vyas, Poorva (2014) Antioxidant properties of lingonberry (Vaccinium vitis-idaea L.) plants. Doctoral (PhD) thesis, Memorial University of Newfoundland.

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Abstract

Lingonberry (Vaccinium vitis-idaea L.) is an economically important fruit crop conventionally propagated by vegetative stem cutting. The present study is an investigation of the effects of different propagation methods as well as different geographical locations on the antioxidant properties of lingonberry plants. The study also aims to determine neuroprotective effects of the lingonberry fruits and leaves against glutamate-mediated excitotoxicity. In this study, it was observed that the leaves of in vitro- derived plants exhibited significantly higher antioxidant enzyme activities as compared to those obtained from ex vitro propagation. The total soluble phenolics, tannins, and flavonoids were enhanced in fruits of the in vitro-propagated plants, whereas in leaves, the levels of these metabolites (except flavonoids) were decreased in the in vitro-derived plants. The study determined that the lingonberry clones collected from different geographical locations showed variability in terms of their antioxidant compounds. A positive correlation was observed between the levels of antioxidant compounds and latitude, altitude, reduced temperature and increased precipitation. Although the clones have been maintained in the same greenhouse environment under similar conditions for about 10 years since their collection date, the climatic conditions had an effect on their adaptation at the developmental stage influencing plant genotypes. The effect of lingonberry extracts were determined on cells subjected to excitotoxicity by treating brain cell cultures of 1 to 2 day old rat pups with glutamate (100 μM) for 24 hours in order to damage the cells by excitotoxicity. Glutamate treatment caused a ~20% cell loss when measured after 24 hours of exposure. While lingonberry fruit extract did not provide protection from glutamate toxicity, leaf extracts showed a significant neuroprotective effect. The greater protective effect of leaf extracts was in correlation with the levels of phenolics and antioxidant capacity. In conclusion, the findings in this dissertation suggest that the tissue culture propagation technique has great advantages especially in enhancing antioxidant compounds as well as for increasing vegetative growth in lingonberry plants. Our findings also suggest that antioxidant levels increase with reduced temperature, increased precipitation, latitude and altitude. Overall, the antioxidant capacity of lingonberry leaves would be potentially beneficial for neuro-protection and slowdown of brain aging, and consumption of lingonberry products could have positive effect on human health.

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