Student Texas A & M International University Laredo, Texas
Body of Abstract: Several species of Acacia were known to have antioxidant activities. A. rigidula, A. berlandieri, A. farnesiana, and A. greggii are Acacia species abundant in South Texas. The aim of this study is to determine and compare the antioxidant activities (AOAs) of these four Acacia species. Leaf extracts obtained from Soxhlet extractions were used to determine AOAs (scavenging activity [SA] and lipid peroxidation inhibition [LPI]). The 2, 2′-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), ferric reducing antioxidant power (FRAP), and ferric thiocyanate lipid peroxidation (FTLP) were performed. The total phenolic content (TPC) was determined using the Folin-Ciocalteu assay. Statistical analysis of the results of the ABTS assays showed significant differences (p < 0.05) in the SA of A. rigidula (64.6%), A. greggii (60.5%), A. berlandieri (40.1%), and A. farnesiana (28.5%). Results from FRAP assays also showed significant differences (p < 0.05) in the SA of A. rigidula (30.8%), A. greggii (19.7%), A. berlandieri (11.2%), and A. farnesiana (8.4%). TPC (mg GAE/g of sample) of A. rigidula (45.7), A. greggii (30.3), A. berlandieri (20.7), and A. farnesiana (19.8) are also significantly different (p< 0.05) from each other. Results showed that the higher the TPC in the Acacia leaf extracts, the higher was the observed SA. On the other hand, FTLP assays showed LPI to be significantly higher (p< 0.05) in A. farnesiana (80.5%) and A. berlandieri (78.9%) compared to A. greggii (77.8%) and A. rigidula (76.7%). In this regard, we assume that other secondary metabolites other than TPC contribute to the LPI activity in A. farnesiana and A. berlandieri. In conclusion, our study reveals that A. rigidula has the highest scavenging activity while A. berlandieri and A. farnesiana extracts have the highest lipid peroxidation inhibition activity.