This study sought to determine the total phenolic content (TPC) of the aqueous leaf extracts of the three selected indigenous plants of the Philippines – Kangkong (Ipomoea aquatica), Duhat (Syzygium cumini) and Apatot (Morinda citrifolia) and to evaluate their antihyperglycemic effects in the blood glucose levels (BGL) of alloxan-induced diabetic mice. The antihyperglycemic effect of the leaf extracts was tested in alloxaninduced diabetic mice. ANOVA was used to analyze the differences among the treatment statistically means at 0.05 level of significance followed by Tukey’s tests. Data analysis showed that the administration of I. aquatica, S. cumini and M. citrifolia improved the BGL of the diabetic mice. Results revealed that S. cumini extract has the highest antihyperglycemic effect with a mean difference to the CD of 219 on the 14th day, followed by I. aquatic and M. citrifolia with 187 and 136.3333, respectively. It is almost comparable with Glibenclamide. Based on the findings, S. cumini has high total phenolic content and antihyperglycemic potential; thereby, making this plant species a very good source of polyphenol and an alternative medication for diabetes.