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AMBHI Services

Services 3

Analytical and related services

Total Antioxidant Capacity

  • Ferric reducing antioxidant power assay (FRAP): The FRAP assay gives fast, reproducible results with a wide variety of biological and food samples. The FRAP assay uses an oxidation/reduction reaction to measure the ability of a sample to reduce iron(III) to iron(II).
  • Trolox equivalent antioxidant capacity (TEAC): The TEAC assay uses the 2,2-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) radical cation (ABTS•+). It has been applied in beverages and foods as well as in biological fluids. The assay is applicable to both hydrophilic and lipophilic environments.

Total groups (spectrophotometric)

  • Carotenoids
  • Polyphenols
  • Flavonols (Traditional rooibos herbal tea contains a variety of flavonols such as rutin and isoquercitrin, all contributing to the antioxidant activity of rooibos tea.)
  • Flavanols (catechins) (Green tea as well as black tea contains various polyphenolic compounds (flavan-3ols) generally known as catechins. Pharmacological functions of catechins have been studied, including protection against coronary heart disease, various types of cancer and inflammatory disease.)
  • Anthocyanins

Individual compounds (HPLC)

  • Carotenoids (carotenes, lutein, lycopene)
  • Resveratrol
  • Ascorbic acid (vitamin C)
  • Epicatechin, epicatechin gallate, epigallocatechin, epigallocatechin gallate, catechin, gallocatechin, gallocatechin gallate, and catechin gallate.
  • Quercetin, kaempferol, apigenin, luteolin, rutin, isoquercitrin, aspalathin
  • Vitamin E (tocopherols; tocotrienols)

Antioxidant enzymes and glutathione

  • Superoxide dismutase (SOD): SODs are metalloenzymes that catalyse the dismutation of the superoxide anion to molecular oxygen and hydrogen peroxide and thus form an important part of the cellular antioxidant defence mechanism. Total SOD activity (cytosolic and mitochondrial) or only cytosolic or mitochondrial SOD activity can be determined.
  • Catalase (CAT): Catalase is a ubiquitous antioxidant enzyme that is present in most aerobic cells.
  • Glutathione reductase (GR): Glutathione reductase is a flavoprotein that catalyses the NADPH-dependent reduction of oxidised glutathione (GSSG) to GSH. This enzyme is essential for the GSH redox cycle, which maintains adequate levels of reduced cellular GSH.
  • Glutathione peroxidase (GPx): Glutathione peroxidase catalyses the reduction of hydroperoxides, including hydrogen peroxide, by reduced glutathione and functions to protect the cell from oxidative damage.
  • Glutathione redox status (GSH/GSSG ratio): Glutathione is a tripeptide widely distributed in both plants and animals. Increased oxidative stress in a cell, causes the ratio of GSH:GSSG (reduced to oxidised glutathione) to decrease, mostly because of the accumulation of GSSG, but also because of an increased reduced glutathione level. This ratio is used as an indicator of oxidative stress in a biological system and may also be used to monitor various antioxidant interventions.

Oxidative lipid and protein damage

  • Conjugated dienes: primary products of lipid peroxidation measured spectrophotometrically
  • Malondialdehyde: these lipid peroxidation aldehyde products react with thiobarbituric acid (TBA) under acidic condition and produce a relatively stable coloured product (MDA-TBARS) quantified spectrophotometrically (measured as thiobarbituric acid reactive substances - TBARS)
  • Protein carbonyls: PC is first coupled with 2,4 dinitrophenylhydrazine (DNPH) and the stable 2,4-dinitrophenylhydrazone (DNP) product is then quantified using either chromatography or spectrophotometry

For any queries related to the services listed above please contact Prof JL Marnewick ( and Mr F Rautenbach (

Mycotoxins and food-borne fungi

  • Sales and Online Ordering of Mycotoxin Analytical Standards (Note: Bank costs are not included)
  • Fusarium verticillioidesculture material
  • Mycological determination of food-borne fungi
  • Consultation services regarding food-borne fungi and their toxins

To order Mycotoxin analytical standards (FB1, FB2 and FB3) online, use our order form. Please complete the form and email it to Dr M Lilly ( and Mrs G Imrie (

AMHBI Fumonisin Sales Order form

LC-MS analyses

The Applied Microbial and Health Biotechnology Institute currently also house a Dionex Ultimate 3000 HPLC, a Bruker amaZon SL mass spectrometer and a Bruker microTOF-Q II mass spectrometer. The COMPASS software is used for data analysis and processing.  The following tools are available on the software: 

  •  SmartFormula and novel SmartFormula 3D
  •  TargetAnalysis™ – for multi-target compound screening
  •  BioTools™ for protein data interpretation
  •  MetaboliteTools™ for metabolite identification
  •  Compass chemical formula generation
  •  Pattern simulation

The COMPASS software includes CHROMELEON and HYStar for the control of the LC/MS.

Analysis and services 

The LC/MS hyphenated technique allows for a variety of analytical studies of complex mixtures. The following analyses/services are offered:

  •  Accurate mass measurements
  •  Identification of unknown compounds
  •  Quantitation
  •  Method development
  •  Sample preparation
  •  Structural elucidation
  •  Confirmation of known compounds

The analysis can be performed in MS (direct injection), LC-MS, LC-MS/ MS, and MS/MS in both positive and negative modes. 

Sample submission

Sample submission is done thorough communication with Dr T Mthethwa ( The analyses are charged at an hourly rate. Once the analysis has been carried out an invoice request form is sent.