title: Pharmacological, genotoxic and phytochemical properties of selected South African medicinal plants used in treating stomach-related ailments.
abstract: BACKGROUND
  The evaluated medicinal plants are used in South African traditional medicine in treating stomach-related ailments.
  
  
  OBJECTIVE
  The study aimed at evaluating the pharmacological, genotoxic and phytochemical properties of the seven selected medicinal plants used for treating stomach-related ailments.
  
  
  METHODS
  Ethyl acetate (EtOAc), ethanol (EtOH) 70% and water extracts of the selected plant parts were evaluated for their antimicrobial and anthelmintic activities using microdilution assays. Gram-positive bacteria (Enterococcus faecalis and Staphylococcus aureus), Gram-negative bacterium (Escherichia coli) and Candida albicans were used for antimicrobial assays. Caenorhabditis elegans was used for the anthelmintic assay. Plant extracts were also assayed for their cyclooxygenase-inhibitory activity against cyclooxygenase-1 and -2 enzymes. The Ames test was used to evaluate the genotoxicity of the plant extracts. A spectrophotometric method was used to determine the total phenolics, gallotannins, flavonoids and saponins.
  
  
  RESULTS
  Twelve extracts exhibited minimum inhibitory concentration (MIC) <1 mg/mL against the bacterial test strains, and five extracts exhibited MIC <1 mg/mL against Candida albicans. The EtOAc extract of Tetradenia riparia had the best minimum lethal concentration (MLC) value (0.004 mg/mL) against Caenorhabditis elegans. All the EtOAc extracts exhibited percentage inhibition in the range of 50.7-94.7% against COX-1 and -2 enzymes at 250 μg/mL. All the plant extracts were non-mutagenic towards Salmonella typhimurium tester strains TA98, TA100 and TA1537 without metabolic activation. Phytochemical analysis revealed relatively high amounts of total phenolics, gallotannins and flavonoids in the evaluated plant extracts.
  
  
  CONCLUSIONS
  The general pharmacological activities exhibited by some of the plant extracts in this study support the traditional uses of the selected plants in treating stomach-related ailments. The Ames test showed that all the plant extracts were non-mutagenic but cytotoxicity tests are needed to ascertain the safety for long-term consumption.
authors.affiliation: Research Centre for Plant Growth and Development, School of Life Sciences, University of KwaZulu-Natal Pietermaritzburg, Scottsville, South Africa.
authors.forename: A
authors.initials: A
authors.lastname: Okem
authors.forename: J F
authors.initials: JF
authors.lastname: Finnie
authors.forename: J
authors.initials: J
authors.lastname: Van Staden
mesh_terms: D000818:Animals; D000890:Anti-Infective Agents / Q000494:pharmacology* / Q000627:therapeutic use; D001419:Bacteria / Q000187:drug effects*; D002107:Caenorhabditis / Q000187:drug effects; D002175:Candida / Q000187:drug effects*; D016861:Cyclooxygenase Inhibitors / Q000494:pharmacology* / Q000627:therapeutic use; D006801:Humans; D047348:Hydrolyzable Tannins / Q000494:pharmacology / Q000627:therapeutic use; D019686:Lamiaceae; D016488:Medicine, African Traditional; D008826:Microbial Sensitivity Tests; D008517:Phytotherapy; D010936:Plant Extracts / Q000737:chemistry / Q000494:pharmacology* / Q000627:therapeutic use; D010946:Plants, Medicinal / Q000737:chemistry*; D059808:Polyphenols / Q000494:pharmacology / Q000627:therapeutic use; D013019:South Africa; D013272:Stomach Diseases / Q000188:drug therapy*
chemical_list: D000890:Anti-Infective Agents; D016861:Cyclooxygenase Inhibitors; D047348:Hydrolyzable Tannins; D010936:Plant Extracts; D059808:Polyphenols