title: Assessing similarity analysis of chromatographic fingerprints of Cyclopia subternata extracts as potential screening tool for in vitro glucose utilisation.
abstract: 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.
authors.affiliation: Department of Food Science, Stellenbosch University, Private Bag X1, Matieland, Stellenbosch, 7602, South Africa.|Department of Viticulture and Oenology, Stellenbosch University, Private Bag X1, Matieland, Stellenbosch, 7602, South Africa.
authors.forename: Alexandra E
authors.initials: AE
authors.lastname: Schulze
authors.affiliation: Post-Harvest and Wine Technology Division, Agricultural Research Council (ARC), Infruitec-Nietvoorbij, Private Bag X5026, Stellenbosch, 7599, South Africa.
authors.forename: Dalene
authors.initials: D
authors.lastname: De Beer
authors.affiliation: Diabetes Discovery Platform, South African Medical Research Council, P.O. Box 19070, Tygerberg, 7505, South Africa.
authors.forename: Sithandiwe E
authors.initials: SE
authors.lastname: Mazibuko
authors.affiliation: Diabetes Discovery Platform, South African Medical Research Council, P.O. Box 19070, Tygerberg, 7505, South Africa.
authors.forename: Christo J F
authors.initials: CJ
authors.lastname: Muller
authors.affiliation: Diabetes Discovery Platform, South African Medical Research Council, P.O. Box 19070, Tygerberg, 7505, South Africa.
authors.forename: Candice
authors.initials: C
authors.lastname: Roux
authors.affiliation: Post-Harvest and Wine Technology Division, Agricultural Research Council (ARC), Infruitec-Nietvoorbij, Private Bag X5026, Stellenbosch, 7599, South Africa.
authors.forename: Elize L
authors.initials: EL
authors.lastname: Willenburg
authors.affiliation: Diabetes Discovery Platform, South African Medical Research Council, P.O. Box 19070, Tygerberg, 7505, South Africa.|Medical Research Center, Institute of Medical Research and Medicinal Plants Studies, P.O. Box 3805, Yaoundé, Cameroon.
authors.forename: Nyemb
authors.initials: N
authors.lastname: Nyunaï
authors.affiliation: Diabetes Discovery Platform, South African Medical Research Council, P.O. Box 19070, Tygerberg, 7505, South Africa.
authors.forename: Johan
authors.initials: J
authors.lastname: Louw
authors.affiliation: Department of Food Science, Stellenbosch University, Private Bag X1, Matieland, Stellenbosch, 7602, South Africa.
authors.forename: Marena
authors.initials: M
authors.lastname: Manley
authors.affiliation: Department of Food Science, Stellenbosch University, Private Bag X1, Matieland, Stellenbosch, 7602, South Africa. JoubertL@arc.agric.za.|Post-Harvest and Wine Technology Division, Agricultural Research Council (ARC), Infruitec-Nietvoorbij, Private Bag X5026, Stellenbosch, 7599, South Africa. JoubertL@arc.agric.za.
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Joubert
mesh_terms: D000818:Animals; D001692:Biological Transport / Q000187:drug effects; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D053998:Cyclopia Plant / Q000737:chemistry*; D004353:Drug Evaluation, Preclinical / Q000379:methods*; D005947:Glucose / Q000378:metabolism*; D051379:Mice; D032342:Muscle Cells / Q000187:drug effects / Q000378:metabolism*; D010936:Plant Extracts / Q000032:analysis* / Q000494:pharmacology*
chemical_list: D010936:Plant Extracts; D005947:Glucose
keywords: Chemometric analysis; Glucose uptake; Honeybush; Isomangiferin; Mangiferin; Scolymoside