Impact of Light Stress on the Synthesis of Both Antioxidants Polyphenols and Carotenoids, as Fast Photoprotective Response in Chlamydomonas reinhardtii: New Prospective for Biotechnological Potential of This Microalga

Abstract

The aim of this study was to investigate the potential role of the microalga Chlamydomonas reinhardtii as an antioxidant source of enriched biomass. This microalga is a model organism deeply investigated for physiological studies, particularly considering carotenoid synthesis in response to stress, to counteract the effects of the formation of free radicals. Less attention has been paid to the profile characterization of other antioxidant compounds, such as polyphenols, which can be synthesized, concomitantly with carotenoids, under photooxidative stress, especially high light. The cultures of C. reinhardtii were exposed to three different light intensities, 70, 800 and 1500 µmoles photons m−2 s−1. The increasing light intensity symmetrically induced the increasing accumulation of both carotenoids and phenolic compounds. The results showed that exposure to high light intensities caused the accumulation of electrons in the electron transport chain, with a reduction in photosynthetic activity. In the same cultures, high light intensity induced the strong increment of polyphenols such as gallic, chlorogenic and coumaric acids, which resulted 6.2-fold, 4-fold and 3.7-fold higher, respectively, than in cells exposed to the lowest intensities. As expected, at the highest light intensity, the strong induction of the xanthophyll cycle and the largest increment of loroxanthin, lutein, α-carotene and ß-carotene could be detected. Antioxidant properties doubled with respect to the initial time, both in acetone and methanol cellular extracts of these cultures, revealing a new potential role for biotechnological application of this microalga.

Chlamydomonas agloeformis from the Ecuadorian Highlands: Nutrients and Bioactive Compounds Profiling and In Vitro Antioxidant Activity

“…Moreover, the existing literature lacks a thorough elucidation of the phenolic composition specific to this particular genus of microalga. Among the few available studies, in a recent one by Faraloni et al [43], the green microalga Chlamydomonas reinhartii showed lower levels of phenolic compounds, especially of chlorogenic, coumaric, and gallic acid, compared to those we found in ChA. Goiris et al [57] studied simple phenols and flavonoids in different microalgal biomass samples and detected p-coumaric, ferulic, and caffeic acid, quercetin, phloretin, apigenin, kaempferol, and catechin but to a lesser extent.…”

“…[41,42]. It is interesting to note that in a recent study by Faraloni et al [43], Chlamydomonas reinhardtii, a green alga of the same genus of ChA, exhibited an enhanced production of polyphenols when exposed to high levels of light, thus indicating that light exposure levels also can influence total phenols content. The polyphenolic content of our extract from ChA was similar to those obtained by Goiris et al [41], who examined biomass from 32 microalgal species and reported an average total polyphenol content of 211 mg GAE/100 g dw.…”

Copper boosts the biostimulant activity of a vegetal-derived protein hydrolysate in basil: morpho-physiological and metabolomics insights

“…Nevertheless, considering that treatments with higher levels of phenols are also less productive, it is probable that both the control plants and the Cu-treated plants have bolstered secondary metabolic pathways at the expense of primary ones ( Prinsloo and Nogemane, 2018 ; Ciriello et al., 2022b ). Phenolic compounds have an antioxidant activity higher than vitamins since they can prevent ROS formation and improve antioxidant cell response due to their ability to chelate metal ions ( Faraloni et al., 2021 ). The problem of excess light correlated to high polyphenols content was not present in the other plant treatments, which showed higher transpiration and carboxylation activity, but significantly lower polyphenols, except for Cu treatment, even if at a lower extent, but without negative consequences on plant fresh weight.…”

Microalgae Produce Antioxidant Molecules with Potential Preventive Effects on Mitochondrial Functions and Skeletal Muscular Oxidative Stress

“…produced higher concentrations of phenolic compounds during stress. The green alga, Chlamydomonas reinhardtii, was able to increase the production of polyphenols during a high light exposure [33]. Anwer et al (2022) determined the total phenol content from several microalgal species using different types of extraction.…”