Avaliação da qualidade e do potencial antioxidante de drogas vegetais comercializadas para o tratamento do diabetes

Abstract

Phenolic compounds are phytochemicals that have antioxidant activity and are present in medicinal plants. For this reason, they are indicated as an alternative for the treatment and prevention of several diseases related to oxidative stress. However, most species of medicinal plants used by the population and commercially available do not have proof of effectiveness, safety and quality. Therefore, the objective of this study was to carry out a comparative analysis of the antioxidant capacity and the levels of phenolic compounds in reference and commercial samples, as well as the analysis of the packages, labels, organoleptic characteristics and foreign material content of herbal drugs marketed to treat diabetes. Based on a survey conducted on the local businesses and specialized literature, the most cited plants were selected for this study. Then, commercial samples of herbal drugs of “canela-de-velho”, “cavalinha”, “chapéu-de-couro”, “estévia”, “jambolão”, “pata-de-vaca” and “salvia” were acquired in pharmacies and natural products stores. Reference samples of these species were herborized and their exsiccates were prepared and deposited in a herbarium. Aqueous extracts were prepared at 5% for the quantification of phenolic compounds (total phenols and total flavonoids) and for the evaluation of antioxidant capacity by total antioxidant capacity assay (CAT) and Oxygen Radical Absorbance Capacity assay (ORAC). The reference samples of “canela-de-velho” and “estévia”, and the comercial samples: 2 (“canela-de-velho”); 29, 30, 31 and 32 (“estévia”); 9 (“chapéu-de-couro”); 18 (“pata-de-vaca”); 23 e 27 (“salvia”) showed the best results for phenolic compounds content and antioxidant activity. In general, commercial samples of one same species showed great variation in the contents of phenolic compounds and antioxidant activity. The reference samples compared to the commercial samples showed great variation for all variables studied. The results indicate the low quality of commercial samples, with no standardization in the processes of the production chain, resulting in different levels of phenolic compounds and significant differences in antioxidant activity. Commercial samples of “cavalinha”, “jambolão” and “pata-de-vaca”, species on the RENISUS list, had their packaging and labels analyzed based on (RDC no 26/2014 and RDC no 66/2014).The protocols described in the 5th edition of the Brazilian Pharmacopoeia were used for the determination of foreign material and for the elaboration of a sensory evaluation questionnaire.No studied sample showed compliance with the technical information required for the packaging. Furthermore, 69.23% of the samples failed the visual examination and the odor evaluation.Only the sample J1 (“jambolão”) was within the limit of 2% w/w of foreign material, as recommended by the Pharmacopoeia.The analyzed samples have low quality and are in disagreement with the requirements of the 5th edition of the Pharmacopeia and the current legislation for herbal drugs, being sold in the food category.The data indicate that the quality control required for medicinal herbal teas are not accomplished as stablished in the law, compromising the quality of the products and putting the health of the consumers at risk.