Phytochemical Profiling, Antioxidant Potentials, and Antimicrobial Properties of Locally-Isolated Chlorococcum and Scenedesmus Species: Sustainable Sources of Bioactive Compounds

Abstract

Microalgae thrive in diverse habitats and possess adaptive mechanisms that enable them to produce unique bioactive compounds. These compounds have gained increasing attention due to their potential applications in the food, medicinal, pharmaceutical, nutraceutical, and cosmetic industries. Despite the growing interest in microalgal bioactive compounds global research on locally-isolated species in Nigeria remains limited. This study evaluated the phytochemical composition, antioxidant potential, and antimicrobial properties of Chlorococcum sp and Scenedesmus sp ethanol extracts. Phytochemical analysis confirmed the presence of alkaloids, flavonoids, saponins, steroids, and phenolic compounds, which exhibit various biological activities. Antioxidant assays revealed concentration-dependent free radical scavenging activities, with the highest DPPH inhibition percentages recorded at 43.1% for Chlorococcum sp and 47.58% for Scenedesmus sp at 1 mg/mL. Reducing power assays confirmed significant antioxidant activity, with absorbance values of 0.52 mg AAE/g DW for Chlorococcum sp and 0.56 mg AAE/g DW for Scenedesmus sp. The reducing power of ethanol extracts also correlated significantly with inhibition capacity, indicating strong antioxidant potential. The antimicrobial evaluation demonstrated the inhibitory effects of ethanol extracts against Escherichia coli and Staphylococcus aureus, with inhibition zones of 26.0 mm for Scenedesmus sp and 20.0 mm for Chlorococcum sp at 500 mg/mL. The MIC values of 125 mg/mL and 250 mg/mL for Scenedesmus sp and Chlorococcum sp respectively, revealed their potency as antibacterial agents. These findings highlight the potential of Chlorococcum sp and Scenedesmus sp as valuable natural sources of bioactive compounds for pharmaceutical and nutraceutical applications.