Estudo comparativo da actividade antioxidante e fitocompostos das macroalgas: Padina boryana, Eucheuma denticulatum, Kappaphycus alvarezii e Ulva lactuca

Abstract

In recent years, there has been an extensive demand for high-value products nutritional and that are free of synthetic compounds, in order to improve the quality of life and prevent diseases that may arise from poor diet. Macroalgae appear as an innovative, sustainable and healthy option. The present study aims to compare the antioxidant activity and the presence of bioactive compounds in extracts of methanol and acetone from the macroalgae Padina boryana, Eucheuma denticulatum, Kappaphycus alvarezii and Ulva lactuca. This is a comparative experimental descriptive study, where four species of marine macroalgae were collected: Padina boryana, Eucheuma denticulatum, Kappaphycus alvarezii (collected on Inhaca Island) and Ulva lactuca (collected on Costa do Sol beach). The macroalgae were placed in thermal boxes and transported to the Mozambique Engineering Laboratory, for subsequent washing and drying in the oven at 50°C for 24-48 hours and then crushed. For the analysis of phytocompounds, methanol and acetone extracts were prepared at 0.01g/ml of solution for subsequent analysis of steroids, tannins, coumarins and alkaloids. For the analysis of antioxidant activity, the extracts were prepared at a concentration of 0.05g/ml, followed by the addition of the phosphomolybdenum complex for readings on the UV spectrophotometer, at 695 nm. The calibration curve was made using 300 µl of ascorbic acid at 0.01g/ml and 3 ml of phosphomolybdenum complex. In colorimetric analyzes of phytocompounds, the presence of metabolites in both extracts, with main emphasis on alkaloids, coumarins and tannins. For antioxidant activity, the two solvents (methanol and acetone) proved to be good extracting solvents, the highest concentrations of the acid were found in the macroalga Kappaphycus alvarezii (3.54mg/g) in the acetone extract and in the Padina boryana macroalgae (2.55mg/g) in methanol extract. Marine macroalgae present a high biotechnological potential characterized by the vast amount of substances with great applicability in different areas, requiring only more studies and development of methodologies that guarantee effectiveness in the analysis of different compounds present in macroalgae.(TRADUÇÃO NOSSA)