Recovery of chlorophyll a derivative from spirulina maxima: its purification and photosensitizing potential

Abstract

Spirulina sp. is a cyanobacterium rich in essential amino acids and pigments such as chlorophyll a, xanthophylls, and phycocyanin. Besides many other applications, chlorophyll a and its derivatives are being studied as photosensitizers in photodynamic therapy for cancer treatment. In this work, two methodologies of solid−liquid extraction were developed, and their performance compared; one using conventional organic solvents and the other using aqueous solutions of ionic liquids (ILs) and surfactants. It was found that an aqueous solution of an ammonium-based ionic liquid was able to increase the yield of extraction of chlorophyll a from Spirulina maxima in 25% compared with the conventional methodology using methanol. Besides, the proposed alternative methodology allows the separation of chlorophyll a from xanthophylls using a simple liquid−liquid extraction. The IL can be recovered by backextraction using ethyl acetate, while the chlorophyll derivative is shown to retain its ability to generate oxygen singlets, which is essential to its potential application as a photosensitizer in photodynamic therapy.