Extraction and characterization of polyphenolic compounds and potassium hydroxycitrate from Hibiscus sabdariffa
Manisha Singh, Thilini Thrimawithana, Ravi Shukla, Benu Adhikari
Abstract
Hibiscus sabdariffa calyces were used to extract the polyphenolic compounds with three different solvents (water, methanol, and ethanol). The augmentation of temperature from 23 °C to 90 °C caused an adverse effect to polyphenols through thermal degradation and reduced antioxidant activity. Methanol and ethanol were more effective solvents than water for extracting polyphenolic compounds. The storage stability study at -30 °C for ten weeks showed that the antioxidant activity of extracts significantly decreased after 6 weeks; however, total phenolic content did not change significantly. Delphinidin 3-O-sambubioside chloride and cyanidin 3-O-sambubioside chloride were found to be the most abundant polyphenolic compounds in all three extracts. Potassium hydroxycitrate (180.14 µg/mg) was extracted from H. sabdariffa calyces, which is the highest reported value so far. Therefore, H. sabdariffa serves as a potential source for extracting potassium hydroxycitrate and phenolic compounds which are important for food and pharmaceutical applications.