title: The 15-lipoxygenase inhibitory, antioxidant, antimycobacterial activity and cytotoxicity of fourteen ethnomedicinally used African spices and culinary herbs.
abstract: BACKGROUND
  Culinary herbs and spices are widely used ethnomedically across Africa. They are traditionally employed in the treatment of several ailments including inflammation disorders, pain alleviation and infectious diseases. Pharmacological studies are necessary to provide a scientific basis to substantiate their traditional use and safety. In this study, the 15-lipoxygenase inhibitory, antioxidant, antimycobacterial and the cytotoxic activities, total phenolic and flavonoid contents of fourteen edible plants were investigated.
  
  
  METHODS
  The 15-lipoxygenase inhibitory activity was evaluated by the ferrous oxidation-xylenol orange (FOX) assay method. The antioxidant activity was determined using free-radical scavenging assays. The antimycobacterial activity was determined by a broth microdilution method against three species of mycobacteria: Mycobacterium smegmatis, Mycobacterium aurum and Mycobacterium fortuitum using tetrazolium violet as growth indicator. The cytotoxicity was assessed by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay on Vero monkey kidney cells.
  
  
  RESULTS
  All the extracts tested had some 15-lipoxygenase inhibitory activity ranging from 32.9 to 78.64%. Adansonia digitata (fruit) had the highest antioxidant capacity (IC₅₀ values of 8.15 μg/mL and 9.16 μg/mL in the DPPH and ABTS assays respectively; TEAC of 0.75 in the FRAP assay) along with the highest amount of total phenolics (237.68 mg GAE/g) and total flavonoids (16.14 mg E/g). There were good correlations between DPPH and ABTS values (R(2) 0.98) and between total phenolics and total flavonoids (R(2) 0.94). Tamarindus indica had significant antimycobacterial activity against Mycobacterium aurum (MIC 78 μg/mL). As could be expected with edible plants, all the extracts had a relatively low cytotoxicity with LC₅₀ values higher than 102 μg/mL with the exception of the two Aframomum species (33 and 74 μg/mL).
  
  
  CONCLUSIONS
  This study provides scientific support for some of the the traditional uses and the pharmacological activities of the culinary herbs and spices investigated. The results suggest that increasing intake of some of these herbs may be useful in preventing or reducing the progression of lifestyle-related diseases. The diversity of the pharmacological activities of the extract from the fruit of Adansonia digitata suggested that this plant might be valuable for application in human and animal health.
authors.affiliation: Phytomedicine Programme, Department of Paraclinical Sciences, Faculty of Veterinary Science, University of Pretoria, Private Bag X04, Onderstepoort 0110, Pretoria, South Africa; Department of Biochemistry, Faculty of Science, University of Dschang, P.O. Box 67, Dschang, Cameroon.
authors.forename: Jean Paul
authors.initials: JP
authors.lastname: Dzoyem
authors.affiliation: Department of Biochemistry, Faculty of Science, University of Dschang, P.O. Box 67, Dschang, Cameroon.
authors.forename: Victor
authors.initials: V
authors.lastname: Kuete
authors.affiliation: Phytomedicine Programme, Department of Paraclinical Sciences, Faculty of Veterinary Science, University of Pretoria, Private Bag X04, Onderstepoort 0110, Pretoria, South Africa.
authors.forename: Lyndy J
authors.initials: LJ
authors.lastname: McGaw
authors.affiliation: Phytomedicine Programme, Department of Paraclinical Sciences, Faculty of Veterinary Science, University of Pretoria, Private Bag X04, Onderstepoort 0110, Pretoria, South Africa. Electronic address: kobus.eloff@up.ac.za.
authors.forename: Jacobus N
authors.initials: JN
authors.lastname: Eloff
mesh_terms: D000349:Africa; D000890:Anti-Infective Agents / Q000737:chemistry / Q000494:pharmacology*; D003296:Cooking / Q000379:methods*; D020834:Ethnopharmacology; D016166:Free Radical Scavengers / Q000494:pharmacology; D006801:Humans; D016859:Lipoxygenase Inhibitors / Q000737:chemistry / Q000494:pharmacology*; D016488:Medicine, African Traditional; D008826:Microbial Sensitivity Tests; D010636:Phenols / Q000494:pharmacology; D028321:Plant Preparations / Q000737:chemistry / Q000494:pharmacology*; D017365:Spices
chemical_list: D000890:Anti-Infective Agents; D016166:Free Radical Scavengers; D016859:Lipoxygenase Inhibitors; D010636:Phenols; D028321:Plant Preparations
keywords: Antimycobacterial; Antioxidant; Culinary herbs; Cytotoxicity; Lipoxygenase