Freshwater microalgae biomasses are a source of bioaccessible bioactive compounds and have antioxidant, antihypertensive, and antidiabetic activity

Abstract

Due to their sustainable production, freshwater microalgae have received attention as an alternative food rich in nutrients and bioactive compounds. This work assessed the composition and bioaccessibility of amino acids (AA), fatty acids (FA), and phenolic compounds (PC) present in the Chlorella vulgaris, Spirulina platensis, Scenedesmus acuminatus, Desmodesmus maximus, and Tetraselmis sp. biomass, and their antioxidant, antihypertensive and antidiabetic in vitro activities. The microalgae had a similar profile of compounds, but the concentration varied significantly between species. Lysine was the most abundant essential AA and palmitic and oleic (ω9) acids were the main FA detected in all microalgae. Moreover, the bioaccessibility was higher than 70 % for most FA, while the bioaccessibility of PC was generally low (<20 %). All microalgae showed significant antidiabetic (∼20-54 % ⍺-amylase inhibition and ∼ 91 % to ∼96 % ⍺-glucosidase inhibition), antihypertensive (∼13-53 % ACE inhibition) and antioxidant (1313.10-1821.60 μM eq Trolox/g) potential. C. vulgaris showed a higher concentration and bioaccessibility of phenolic compounds, resulting in an increased antidiabetic activity (higher α-glucosidase inhibition). S. platensis showed higher concentrations of fatty acids (palmitic, palmitoleic, and linoleic). D. maximus was characterized by higher concentrations and bioaccessibility of amino acids and an increased antioxidant and antidiabetic activities. Finally, Tetraselmis sp. presented improved concentration of tyrosine and increased antihypertensive activity. Therefore, the results can support the application of microalgae biomass in new functional foods for delivering bioactive compounds, primarily essential AA and FA, targeting specific niches that benefit from their potential health advantages. Findings underscore the commercial applicability of microalgae-based products.