Phytochemistry, Phenolic Contents and Free Radical Scavenging of Bauhinia thoningii kurtz and Ricinus communis L Extracts as Possible Contribution to Medicinal Effects

Aims: Current research places premium on isolation bioactive constituents and antioxidants activities of plants. However, the chemical constituents and antioxidant potential of many local medicinal plants are still unknown. This study sought to assay the phytochemistry and in vitro antioxidant potential of Bauhinia thoningii (leaf) and Ricinus communis (root) as a likely justification of scientifically proved and folklore uses.
Study Design: Air-dried parts of the plants were extracted in solvents and evaporated in-vacuo. The extracts were analysed for secondary metabolites.
Place and Duration of Study: Sample: Department of Veterinary Physiology, Biochemistry and Pharmacology, University of Ibadan, Ibadan, Nigeria (FHI 108864). The confirmatory identification of the plants was done at Forestry Research Institute of Nigeria (FRIN) with voucher deposited, between 2012 and 2013.
Methodology: Standard procedures were used to carry out phytochemical analyses of aqueous and methanol extracts of the plants. In vitro antioxidant effects of the plants were tested by ferrous reducing antioxidant property (FRAP) and 1,1-diphenyl-2-picrylhydrazyl (DPPH) scavenging ability. The total phenol contents in the extracts were determined by the modified Folin-Ciocalteu method.
Results: Anthraquinone, phenols and cardenolide were detected in all the plants. The FRAP values of Ricinus communis and Bauhinia thoningii were 915.3 µmol/g and 620.4 µmol/g while their DPPH scavenging ability was 93.6% and 71.4%. R. communis which showed higher phenolic, 90.33 mg/g, content as against 62.14 mg/g for B. thoningii.
Conclusion: Results from this study showed a direct relationship between the total phenol constituents and antioxidant activities of the plants. The high phenolic content and the observed radical scavenging activities could be some of the factors responsible for medicinal activities. This may also be clue to the likely mechanism of action of the plants in managing the disease conditions.