Comparative seasonal analysis of IC50, total antioxidant capacity, phenolics, and flavonoids of some vegetable plants from the aquaponics system

Seasonal factors such as temperature, solar UV-light intensity, and daylight length can induce changes in the water quality properties and, hence, the nutritional compositions of plants. This comparative study was carried out for the consecutive four (4) seasons (winter, spring, summer, and autumn) to determine the influence of seasonal variations on the 50% inhibitory concentration (IC50), total antioxidant capacity (TAC), total phenolics content (TPC), and total flavonoids content (TPC) of the red chili fruit (RCF), red tomato fruit (RTF), green leafy spinach (GLS), and green leafy lettuce (GLL) collected from a coupled commercial aquaponics system. The IC50, TAC, TPC, and TFC concentration levels indicated a significant (P0.05) difference in the summer compared with the winter, spring, and autumn. The RCF extract indicated the lowest IC50, thus greater scavenging power in comparison to RTF, GLS, and GLL extracts. Similarly, the RCF showed the highest TAC and TPC, while the GLL showed the highest TFC. In this study, variations in seasons have induced changes in the IC50, TAC, TPC, and TFC concentration levels of the RCF, RTF, GLS, and GLL extracts.