title: Antioxidant and antidiabetic profiles of two African medicinal plants: Picralima nitida (Apocynaceae) and Sonchus oleraceus (Asteraceae).
abstract: BACKGROUND
  Diabetes mellitus (DM) is a metabolic disease characterized by chronic hyperglycaemia generally associated with oxidative stress. The present study aims at evaluating the antioxidant and antidiabetic potential of methanol and hydroethanol extracts of the stem bark and leaves of Pricralima nitida and the Sonchus oleraceus whole plant respectively.
  
  
  METHODS
  The in vitro antioxidant activity was assessed using 1,1-Diphenyl-2-picrilhydrazyl (DPPH) for free radical-scavenging properties of the extracts, and the Folin-Ciocalteu method in determining their phenol contents. The antidiabetic activity was tested in mice following streptozotocin diabetes induction, and selected oxidative stress markers (Malondialdehyde, Hydrogen peroxides and Catalase) were measured in order to evaluate the level of oxidative stress in treated animals.
  
  
  RESULTS
  The in vitro antioxidant activity using DPPH showed IC50 ranging from 0.19 ± 0.08 to 1.00 ± 0.06 mg/mL. The highest activity was obtained with the hydroethanol extracts of S. oleraceus (0.19 mg/mL and P. nitida (0.24 mg/mL). Polyphenol contents ranged from 182.25 ± 16.76 to 684.62 ± 46.66 μg Eq Cat/g. The methanol extract of P. nitida showed the highest activity, followed by the hydroethanol extract of S. oleraceus (616.89 ± 19.20 μEq Cat/g). The hydroethanol extract of whole plants (150 mg/Kg) and methanol leave extract of P. nitida (300 mg/Kg) exhibited significant antidiabetic activities with 39.40% and 38.48% glycaemia reduction, respectively. The measurement of stress markers in plasma, liver and kidney after administration of both extracts showed significant reduction in MDA and hydrogen peroxide levels, coupled with a substantial increase in catalase activity.
  
  
  CONCLUSIONS
  These findings suggest that S. oleraceus whole plant and P. nitida leaves possess both antidiabetic and antioxidant properties, and therefore could be used as starting point for the development of herbal medicines and/or source of new drug molecules against diabetes.
authors.forename: Clautilde Mofor
authors.initials: CM
authors.lastname: Teugwa
authors.forename: Pascaline Chouadeu
authors.initials: PC
authors.lastname: Mejiato
authors.forename: Denis
authors.initials: D
authors.lastname: Zofou
authors.forename: Bruno Tugnoua
authors.initials: BT
authors.lastname: Tchinda
authors.forename: Fabrice Fekam
authors.initials: FF
authors.lastname: Boyom
mesh_terms: D000349:Africa; D000818:Animals; D000975:Antioxidants / Q000494:pharmacology / Q000627:therapeutic use*; D029062:Apocynaceae / Q000737:chemistry*; D001713:Biphenyl Compounds / Q000378:metabolism; D001786:Blood Glucose / Q000378:metabolism; D002374:Catalase / Q000097:blood; D003921:Diabetes Mellitus, Experimental / Q000097:blood / Q000188:drug therapy*; D006861:Hydrogen Peroxide / Q000097:blood; D006943:Hyperglycemia / Q000097:blood / Q000188:drug therapy; D007004:Hypoglycemic Agents / Q000494:pharmacology / Q000627:therapeutic use*; D008297:Male; D008315:Malondialdehyde / Q000097:blood; D051379:Mice; D018384:Oxidative Stress / Q000187:drug effects*; D008517:Phytotherapy; D010851:Picrates / Q000378:metabolism; D010936:Plant Extracts / Q000494:pharmacology / Q000627:therapeutic use; D018514:Plant Structures; D059808:Polyphenols / Q000494:pharmacology / Q000627:therapeutic use; D031184:Sonchus / Q000737:chemistry*
chemical_list: D000975:Antioxidants; D001713:Biphenyl Compounds; D001786:Blood Glucose; D007004:Hypoglycemic Agents; D010851:Picrates; D010936:Plant Extracts; D059808:Polyphenols; D008315:Malondialdehyde; D006861:Hydrogen Peroxide; C004931:1,1-diphenyl-2-picrylhydrazyl; D002374:Catalase