Evaluation of various extraction techniques for obtaining bioactive extracts from pine seeds

Evaluation was made of four extraction techniques (maceration with magnetic stirring, ultrasound-assisted extraction, microwave-assisted extraction, and extraction with pressurised liquids) to obtain polyphenolic extracts from pine seeds. The technique and temperature conditions that produce extracts containing the largest quantity of polyphenols were determined. Extraction assisted by microwave and extraction with pressurised liquids at temperatures >100 °C gave the best results. The correlation between the antioxidant activity of the extracts and the quantity of polyphenols that they contain has also been determined; a direct relationship between these two variables was found in the majority of extracts.The general biological activity of the extracts was also evaluated using the etiolated wheat coleoptile bioassay; extracts obtained with pressurised liquids, and with maceration under agitation, were the most bioactive. An inverse relationship between the degree of bioactivity and the extraction temperature was found.