Influence of oxidation state of guava leaves on the content of oligomeric procyanidins

Medicinal plants have usually been applied to control the blood glucose or reduce the diabetic complications; they have the potential to increase the life span and quality of life in these patients. Guava leaves (Psidium guajava L.) are considered native to Mexico but today they are extended throughout South America, Europe, Africa, and Asia. Different studies considered these leaves as a promising source of phenolic compounds for diabetes treatment. Several authors reported that the presence of flavan-3-ols compounds in Psidium guajava leaf make a contribution towards the inhibition on the glycation of protein, because of that they suggested their consumption for prevention of diabetes complication. On the basis of these considerations, the aim of this work was to investigate the oligomeric procyanidins content in guava leaves by NP-HPLC-FLD. Three different guava leaves samples were used. Samples were collected in the Tropical Coast of Granada in Motril. The three samples differed on their oxidation state (low, medium and high). The results obtained by chromatographic analysis reported that guava leaves have a high degree of polymerization of procyanidins; in fact it ranged between monomers to tridecamers plus the polymers. Dimers, trimers, polymers and monomers are the most abundant flavan-3-ols detected. The state of oxidation affected significantly the procyanidin content. In fact, the highest content was detected in the leaves with low oxidation state.