Claudio Coimbra Teixeira

Absence of antihyperglycemic effect of jambolan in experimental and clinical models.

The use of alternative therapies to treat diabetes, including teas prepared with different vegetables, is widespread in Brazil. In Porto Alegre, a southern city of Brazil, the tea prepared from leaves of Syzygium cumini (L.) Skeels or S. jambos (L.) Alst has been report to be used frequently by diabetic patients. We investigated the postulated antihyperglycemic effect of the S. cumini (L.) Skeels in three experiments. In the first, a randomized, parallel, placebo controlled trial, tea prepared from leaves of S. cumini did not present any antihyperglycernic effect in 30 non-diabetic young volunteers submitted to a glucose blood tolerance test. In the animal experiments, we tested the effect of increasing doses of the crude extract prepared from leaves of S. cumini administrated for 2 weeks, on the post-prandial blood glucose level of normal rats and rats with streptozotocin-induced diabetes mellitus. The treatment did not produce any antihyperglycernic effect in both models. These results do not rule out hypoglycemic effects in patients with type 2 diabetes mellitus, but strongly suggest that, for a while, the jambolan can not be recommended as an antihyperglycemic treatment.

The effect of Syzygium cumini (L.) skeels on post-prandial blood glucose levels in non-diabetic rats and rats with streptozotocin-induced diabetes mellitus

This study was undertaken to investigate whether a tea prepared from Syzygium cumini, reported to be used by diabetics in Porto Alegre, Brazil, might have an antihyperglycemic effect in experimental models. Teas prepared from leaves and seeds of S. cumini, in concentrations ranging from 2-64 g/l, were administered, as water substitute for 14-95 days, to 16 groups with 8-9 normal albino rats and to four groups with 10-12 rats with streptozotocin-induced diabetes mellitus. Post-prandial blood glucose levels were determined by the glucose oxidase method on blood samples obtained by decapitation. None of the tea concentration had any detectable antihyperglycemic effect either in normal or in diabetic rats, suggesting that this plant, prepared in a manner similar to that employed by humans, is destitute of an antihyperglycemic effect.

Effect of Tea Prepared From Leaves of Syzygium jambos on Glucose Tolerance in Nondiabetic Subjects

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