Effect of methanol solvent concentration on the extraction of bioactive compounds using ultrasonic-assisted extraction (UAE) from Spirulina platensis

Abstract

Spirulina platensis is a blue-green algae that contains bioactive compounds as a source of antioxidants. Methanol is a polar solvent; it has similarities to the content of the bioactive compound Spirulina platensis, which is polar. This study aimed to determine the effect of different concentrations of methanol solvent (50%, 70%, 96%) using UAE on the content of bioactive antioxidant compounds from Spirulina platensis. The parameters observed were yield, antioxidant activity, phytochemical screening, and GC-MS. The results showed that the difference in the concentration of methanol solvent using UAE significantly affected the antioxidant activity of the Spirulina platensis extract. The highest antioxidant activity was found in Spirulina platensis extract with 50% methanol solvent concentration using UAE with an average inhibition value of 91.81%. The yield value from the Spirulina platensis extract with a 50% methanol concentration was 9.3%. The qualitative phytochemical screening test carried out on Spirulina platensis extract with 50% methanol solvent using UAE showed positive results for flavonoid compounds, alkaloids, tannins and phenols. GC-MS analysis on Spirulina platensis with 50% methanol as a solvent using UAE resulted in 5 types of the most dominant compounds, pentadecanoic acid, 9-Ooctadecenoic acid, hexadecanoic acid, hexadecanal, and 1- nonadecene.