Profiles of carotenoids and amino acids and total phenolic compounds of the red alga Pterocladiella capillacea exposed to cadmium and different salinities

Abstract

The in vitro effect of cadmium (Cd) on apical segments of the red macroalga Pterocladiella capillacea was examined. Over a period of 7 days, the segments were cultivated with a combination of different salinities (25, 35, and 45 psu) and Cd concentrations ranging from 0.17 to 0.70 ppm. This study aimed to evaluate the effects of Cd exposure at various salinities on profiles of carotenoids amino acids and phenolic compounds. Carotenoid profile of control (0 ppm Cd) and Cd-treated plants of P. capillacea showed the presence of lutein, zeaxanthin, β-cryptoxanthin, α-carotene, trans-β-carotene and cis-β-carotene. Significant increase was found for almost all carotenoids, 0.35 ppm Cd + 25 psu, 0.70 ppm Cd + 25 psu, and 0 ppm Cd + 45 psu. Total phenolic compounds of P. capillacea had an overall decrease with treatments of Cd and 25 or 45 psu. Twenty essential amino acids were quantified in P. capillacea samples. At 0 ppm Cd and using baseline control of 35 psu, low and high salinity levels (25 and 45 psu, respectively) significantly altered total amino acid content. Apparently, salinity plays a greater role in amino acid response than Cd concentration. Therefore, more studies with intensified salinity stress over long-term exposure could confirm the major effect of the suggested treatment on this species.