Saturday, 25 March 2017

In vitro anti-diabetic activity of flavonoids and pheophytins from Allophylus cominia Sw . on PTP1B, DPPIV, alpha-glucosidase and alpha-amylase enzymes

Volume 203, 5 May 2017, Pages 39–46



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).


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.


The flavonoid rich fractions from A. cominia inhibited DPPIV enzyme (75.3±2.33%) at 30 µg/ml and produced a concentration-dependent inhibition against DPPIV with a Ki value of 2.6 µg/ml. At 30 µg/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 3 µg/ml, 0.64 µg/ml and 0.88 µg/ml respectively. At 30 µg/ml, the flavonoid fraction significantly inhibited α-glucosidase enzyme (86±0.3%) in a concentration-dependent pattern with a Ki value of 2 µg/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.


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.

Graphical abstract



  • PTP1B, (Protein Tyrosine Phosphatase 1B);
  • DPPIV, (Dipeptidyl peptidase-4);
  • Ki, (inhibitory constant);
  • TFMS (, [Bis(4-trifluoromethylsulfonamidophenyl)−1,4-diisopropylbenzine), P32/98 ({(3N-[(2S, 3S)−2-amino-3-methyl-pentanoyl]−1,3-thiazolidine) hemifumarate);
  • T2-DM, type 2 diabetes mellitus)


  • Allophylus cominia;
  • DPPIV;
  • PTP1B;
  • Alpha-glucosidase;
  • And α-amylase