In vitro anti-diabetic activity of flavonoids and pheophytins from Allophylus cominia Sw . on PTP1B, DPPIV, alpha-glucosidase and alpha-amylase enzymes.
BACKGROUND
Ethno-botanical information from diabetic patients in Cuba led to the identification of Allophylus cominia as a possible source of new drugs for the treatment of type 2 diabetes mellitus (T2-DM).


METHODS
Chemical characterization of the extracts from A. cominia was carried out using chromatographic and spectroscopic methods. The extracts were tested for their activity on PTP1B, DPPIV, α-glucosidase enzymes and α-amylase.


RESULTS
The flavonoid rich fractions from A. cominia inhibited DPPIV enzyme (75.3±2.33%) at 30µg/ml and produced a concentration-dependent inhibition against DPPIV with a Ki value of 2.6µg/ml. At 30µg/ml, flavonoids and pheophytins extracts significantly inhibited PTP1B enzyme (100±2.6% and 68±1% respectively). The flavonoids, pheophytin A and pheophytin B fractions showed significant concentration-dependent inhibition against PTP1B with Ki values of 3µg/ml, 0.64µg/ml and 0.88µg/ml respectively. At 30µg/ml, the flavonoid fraction significantly inhibited α-glucosidase enzyme (86±0.3%) in a concentration-dependent pattern with a Ki value of 2µg/ml. None of the fractions showed significant effects on α-amylase. Fatty acids, tannins, pheophytins A and B, and a mixture of flavonoids were detected in the methanolic extract from A. cominia. The identified flavonoids were mearnsitrin, quercitrin, quercetin-3-alloside, and naringenin-7-glucoside.


CONCLUSIONS
The pharmacological effects of the extracts from A. cominia earlier observed in experimental diabetic models was confirmed in this study. Thus a new drug or formulation for the treatment of T2-DM could be developed from A. cominia.
Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, 161 Cathedral Street, Glasgow G4 0RE, United Kingdom. Electronic address: dima.semaan@hotmail.com.
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Semaan
Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, 161 Cathedral Street, Glasgow G4 0RE, United Kingdom; Department of Chemistry, University of Agriculture, PMB 2373 Makurdi, Nigeria.
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Igoli
Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, 161 Cathedral Street, Glasgow G4 0RE, United Kingdom.
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Young
National Centre for Animal and Plant Health (Centro Nacional de Sanidad Agropecuaria), San José de las Lajas, Mayabeque, Cuba.
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Marrero
Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, 161 Cathedral Street, Glasgow G4 0RE, United Kingdom.
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Gray
Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, 161 Cathedral Street, Glasgow G4 0RE, United Kingdom.
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Rowan
D000818:Animals; D003924:Diabetes Mellitus, Type 2 / Q000139:chemically induced / Q000188:drug therapy; D018819:Dipeptidyl Peptidase 4 / Q000187:drug effects / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D005419:Flavonoids / Q000008:administration & dosage / Q000302:isolation & purification / Q000494:pharmacology*; D007004:Hypoglycemic Agents / Q000008:administration & dosage / Q000302:isolation & purification / Q000494:pharmacology; D010674:Pheophytins / Q000008:administration & dosage / Q000302:isolation & purification / Q000494:pharmacology*; D010936:Plant Extracts / Q000008:administration & dosage / Q000737:chemistry / Q000494:pharmacology*; D054562:Protein Tyrosine Phosphatase, Non-Receptor Type 1 / Q000037:antagonists & inhibitors / Q000378:metabolism; D029631:Sapindaceae / Q000737:chemistry*; D013552:Swine; D000516:alpha-Amylases / Q000037:antagonists & inhibitors / Q000378:metabolism; D000520:alpha-Glucosidases / Q000187:drug effects / Q000378:metabolism
D005419:Flavonoids; D007004:Hypoglycemic Agents; D010674:Pheophytins; D010936:Plant Extracts; D054562:Protein Tyrosine Phosphatase, Non-Receptor Type 1; D000516:alpha-Amylases; D000520:alpha-Glucosidases; D018819:Dipeptidyl Peptidase 4
Allophylus cominia; Alpha-glucosidase; And α-amylase; DPPIV; PTP1B