Comparative Study of the Antioxidant Constituents, Activities and the GC-MS Quantification and Identification of Fatty Acids of Four Selected Species.

Mill. (Asteraceae) is a plant genus comprising distinctively of aromatic plants of about 500-600 species. Since most of these plants have not been previously studied, extensive profiling helps to validate their folkloric uses and determine their potential value as sources of plant-derived drug candidates. This study, therefore, aims to investigate the antioxidant activity (DPPH, NO, FRAP); total antioxidant capacity, total phenolic, total flavonoid, and fatty acid compositions of the aqueous acetone extracts from four plants namely, , and . The results obtained showed that the extract had the best DPPH radical scavenging activity (IC = 11.85 ± 3.20 µg/mL) and extract had the best nitric oxide scavenging activity (IC = 20.81 ± 3.73 µg/mL), while Schrank extract (0.636 ± 0.005 µg/mL) demonstrated the best ferrous reducing power, all of which are comparable with results from ascorbic acid used as the standard. The IC values of the radical scavenging activity ranged from 11.85-41.13 µg/mL (DPPH), 20.81-36.19 µg/mL (NO), and 0.505-0.636 µg/mL (FRAP), for all the plants studied. The has the highest total antioxidant capacity (48.50 ± 1.55 mg/g), highest total phenolic content (54.69 ± 0.23 mg/g), and highest total flavonoid content (56.19 ± 1.01 mg/g) compared with other species. The fatty acid methyl esters were analysed using gas chromatography-mass spectrometry (GC-MS). The results obtained showed variations in the fatty acid composition of the plant extracts, with having the highest saturated fatty acid (SFA) content (7184 µg/g) and polyunsaturated fatty acid (PUFA) content (7005.5 µg/g). In addition, had the highest monounsaturated fatty acid (MUFA) content (1150.3 µg/g), while had the highest PUFA:SFA ratio of 1.202. In conclusion, the findings from this study revealed that Schrank, , , are repositories of natural bioactive compounds with potential health-promoting benefits that need to be investigated, for both their antioxidant activity in a number of disease conditions and for further exploration in drug discovery and development projects.