Phytochemical Profiling, and Antioxidant Potentials of South African and Nigerian Loranthus micranthus Linn.: The African Mistletoe Exposé

Abstract

Loranthus micranthus Linn. (Loranthaceae) is a botanically significant hemiparasite that grows on tree branches or trunks and is used in traditional medicine. This study compares the antioxidant activity and qualitative phytochemical screening of Nigerian and South Africa Loranthus micranthus Linn. Standard techniques for phytochemical screening were deployed while thin layer chromatography (TLC) bio-autography was utilized to analyze antioxidants qualitatively. Quantitative antioxidant analysis was performed using 2,2-diphenyl-1-picrylhydrazyl (DPPH); hydrogen peroxide (H2O2) free-radical scavenging; and ferric chloride reducing power. The results of qualitative phytochemical screening revealed the presence of flavonoids; glycosides; saponins; phenolic compounds; phlobatannins; tannins; and terpenoids. As for the antioxidant potentials of the four extracts—i.e., Nigerian dichloromethane (NGDCM); South African dichloromethane (SADCM); Nigerian methanol (NGMeOH); and South African methanol (SAMeOH)—the SADCM extract had more creamy bands compared to the Nigerian, thus indicating potentially more antioxidant compounds. A better complementary antioxidant potential was observed for the Nigerian methanol extracts over their South African counterparts. The DPPH quantitative analyses underpin that the SADCM exhibited greater scavenging activity compared to the NGDCM, but this was less than the gallic acid control, with the highest activity at a concentration of 0.2 mg/mL and 0.4 mg/mL, respectively. However, as the concentration increased from 0.6 to 1.0 mg/mL, the SADCM again dominated in its antioxidant potential over all the analytes. The half maximal inhibitory concentration (IC50) values obtained were [SADCM = 0.31 mg/mL, NGDCM = 0.51 mg/mL, SAMeOH = 0.51 mg/mL, NGMeO = 0.17, gallic acid = 1.17 mg/mL, and BHT = 1.47 Mg/mL)]. Both the H2O2 scavenging and the Fe3+ to Fe2+ reduction assays mirrored a similar trend in the antioxidant potentials of all the analytes except for the BHT, which performed better in the ferric chloride reduction assay at a concentration of 0.2–06 mg/mL. Based on the facts gathered, it can be inferred that the South African and Nigerian Loranthus micranthus Linn. are chemically equivalent. This is in support of their similar morphology and taxonomical classification, notwithstanding the environmental, biological, and edaphic impacts experienced by each plant.