Assessing similarity analysis of chromatographic fingerprints of Cyclopia subternata extracts as potential screening tool for in vitro glucose utilisation

• Published in: Analytical and bioanalytical chemistry 2016-01, Vol.408 (2), p.639-649
• Main Authors: Schulze, Alexandra E., De Beer, Dalene, Mazibuko, Sithandiwe E., Muller, Christo J. F., Roux, Candice, Willenburg, Elize L., Nyunaï, Nyemb, Louw, Johan, Manley, Marena, Joubert, Elizabeth
• Format: Article
• Language: English
• Subjects: Analysis; Analytical Chemistry; Animals; Antidiabetics; Biochemistry; Biological activity; Biological Transport - drug effects; Characterization and Evaluation of Materials; Chemistry; Chemistry and Materials Science; Chromatography; Chromatography, High Pressure Liquid - methods; Cyclopia; Cyclopia Plant - chemistry; Diabetes; Drug Evaluation, Preclinical - methods; Effectiveness; Fingerprints; Food Science; Glucose; Glucose - metabolism; Herbal medicine; High performance liquid chromatography; In vitro testing; Laboratory Medicine; Liquid chromatography; Medical research; Mice; Monitoring/Environmental Analysis; Muscle Cells - drug effects; Muscle Cells - metabolism; Phenols; Physiological aspects; Plant Extracts - analysis; Plant Extracts - pharmacology; Principal components analysis; Quality control; Quantitative analysis; Research Paper; Similarity; Uptakes
• ISSN: 1618-2642; 1618-2650
• DOI: 10.1007/s00216-015-9147-7

Similarity analysis of the phenolic fingerprints of a large number of aqueous extracts of Cyclopia subternata , obtained by high-performance liquid chromatography (HPLC), was evaluated as a potential tool to screen extracts for relative bioactivity. The assessment was based on the (dis)similarity of their fingerprints to that of a reference active extract of C. subternata , proven to enhance glucose uptake in vitro and in vivo. In vitro testing of extracts, selected as being most similar ( n  = 5; r  ≥ 0.962) and most dissimilar ( n  = 5; r  ≤ 0.688) to the reference active extract, showed that no clear pattern in terms of relative glucose uptake efficacy in C2C12 myocytes emerged, irrespective of the dose. Some of the most dissimilar extracts had higher glucose-lowering activity than the reference active extract. Principal component analysis revealed the major compounds responsible for the most variation within the chromatographic fingerprints, as mangiferin, isomangiferin, iriflophenone-3- C -β- d -glucoside-4- O -β- d -glucoside, iriflophenone-3- C -β- d -glucoside, scolymoside, and phloretin-3′,5′-di- C -β- d -glucoside. Quantitative analysis of the selected extracts showed that the most dissimilar extracts contained the highest mangiferin and isomangiferin levels, whilst the most similar extracts had the highest scolymoside content. These compounds demonstrated similar glucose uptake efficacy in C2C12 myocytes. It can be concluded that (dis)similarity of chromatographic fingerprints of extracts of unknown activity to that of a proven bioactive extract does not necessarily translate to lower or higher bioactivity. Graphical Abstract (Dis)similarity of HPLC fingerprints is not predictive of relative in vitro glucos uptake efficacy of C. subternata extracts