Antioxidant, anticancer, and anti-inflammatory potential of carotenoids produced by green microalga Asterarcys quadricellulare (K.Behre) E. Hegewald & A. W. F. Schmidt

Microalgae represents one of the most promising sources of bioactive compounds for the nutraceutical, pharmaceutical, cosmetics, and food industries. Among the bioactive compounds, carotenoids are highlighted and commercially valuable because of their significant therapeutic potential. In this study, the Chlorophycean microalga Asterarcys quadricellulare was isolated, and cultured, and carotenoid-enriched biomass was produced under nutrient-limited conditions. Carotenoids were analyzed using HPLC, and the major carotenoids identified are β-carotene, astaxanthin, lutein, and canthaxanthin. The carotenoid extracts were tested for possible antioxidant, cytotoxic, and anti-inflammatory activities. The antioxidant activity was assessed by DPPH assay and the carotenoid extract showed higher radical scavenging activity. In vitro, cytotoxic assay against human cancerous cell lines and noncancerous cell lines was performed using MTT assay. The carotenoid extract showed prominent cytotoxic activity against HeLa (human cervical cancer) and Ht29 (human colon cancer) cell lines. Significant inhibition of cell functions was observed against cancerous cell lines and extract does not promote toxicity to the noncancerous RAW 264.7 macrophage cell line. The anti-inflammatory potential of the carotenoids against LPS stimulated RAW 264.7 macrophage cell line was performed and the carotenoid extract inhibited the pro-inflammatory mediators such as COX, LOX, iNOS, and MPO. This study denotes the potential of A. quadricellulare as a source of natural carotenoids and their potential use in preventing and treating human diseases.