title: In vitro antioxidant capacity and free radical scavenging evaluation of active metabolite constituents of Newbouldia laevis ethanolic leaf extract.
abstract: BACKGROUND
  The aim of the present study was to evaluate the in vitro antioxidant and free radical scavenging capacity of bioactive metabolites present in Newbouldia laevis leaf extract.
  
  
  RESULTS
  Chromatographic and spectrophotometric methods were used in the study and modified where necessary in the study. Bioactivity of the extract was determined at 10 μg/ml, 50 μg/ml, 100 μg/ml, 200 μg/ml and 400 μg/ml concentrations expressed in % inhibition. The yield of the ethanolic leaf extract of N.laevis was 30.3 g (9.93%). Evaluation of bioactive metabolic constituents gave high levels of ascorbic acid (515.53 ± 12 IU/100 g [25.7 mg/100 g]), vitamin E (26.46 ± 1.08 IU/100 g), saponins (6.2 ± 0.10), alkaloids (2.20 ± 0.03), cardiac glycosides(1.48 ± 0.22), amino acids and steroids (8.01 ± 0.04) measured in mg/100 g dry weight; moderate levels of vitamin A (188.28 ± 6.19 IU/100 g), tannins (0.09 ± 0.30), terpenoids (3.42 ± 0.67); low level of flavonoids (1.01 ± 0.34 mg/100 g) and absence of cyanogenic glycosides, carboxylic acids and aldehydes/ketones. The extracts percentage inhibition of DPPH, hydroxyl radical (OH.), superoxide anion (O2 .-), iron chelating, nitric oxide radical (NO), peroxynitrite (ONOO-), singlet oxygen (1O2), hypochlorous acid (HOCl), lipid peroxidation (LPO) and FRAP showed a concentration-dependent antioxidant activity with no significant difference with the controls. Though, IC50 of the extract showed significant difference only in singlet oxygen (1O2) and iron chelating activity when compared with the controls.
  
  
  CONCLUSIONS
  The extract is a potential source of antioxidants/free radical scavengers having important metabolites which maybe linked to its ethno-medicinal use.
authors: Josiah Bitrus
authors: JB
authors: Habu
authors: Bartholomew Okechukwu
authors: BO
authors: Ibeh
mesh_terms: D000975:Antioxidants / Q000302:isolation & purification*; D029402:Bignoniaceae / Q000737:chemistry*; D005419:Flavonoids / Q000032:analysis; D016166:Free Radical Scavengers / Q000302:isolation & purification*; D017665:Hydroxyl Radical / Q000032:analysis; D020128:Inhibitory Concentration 50; D007502:Iron Chelating Agents / Q000302:isolation & purification; D015227:Lipid Peroxidation / Q000502:physiology; D055442:Metabolome / Q000502:physiology*; D009549:Nigeria; D009569:Nitric Oxide / Q000378:metabolism; D010636:Phenols / Q000032:analysis; D010936:Plant Extracts / Q000302:isolation & purification* / Q000494:pharmacology; D018515:Plant Leaves / Q000737:chemistry*; D017382:Reactive Oxygen Species / Q000302:isolation & purification; D064210:Secondary Metabolism / Q000502:physiology; D014815:Vitamins / Q000302:isolation & purification / Q000378:metabolism
chemical_list: D000975:Antioxidants; D005419:Flavonoids; D016166:Free Radical Scavengers; D007502:Iron Chelating Agents; D010636:Phenols; D010936:Plant Extracts; D017382:Reactive Oxygen Species; D014815:Vitamins; D009569:Nitric Oxide; D017665:Hydroxyl Radical