Extraction and quantification of oxalic acid in leaves of plant species used in the treatment of chronic non-communicable diseases

Abstract

Introduction: Chronic non-communicable diseases (CNCDs) are a group of diseases characterized by having the highest mortality and morbidity rates in the world. Despite the increase in new drug technologies, the use of medicinal plants as an aid in therapy for these diseases is a widespread reality. However, most plant species contain inorganic crystals of calcium oxalate, a product of plant metabolism, which has several functions in plant tissues. For the human species, its ingestion is associated with the arising of kidney problems such as urinary lithiasis, especially in people who have a predisposition to these conditions. Aim: To determine the amount of oxalic acid in plant species, which are used in the treatment of CNCDs. Methodology: After collection and characterization the plant species, aqueous and acidic extracts were obtained from 0.5 g of the plant drug of each species and, subsequently, were titrated with a standardized 0.02 mol.L-1 potassium permanganate solution and the concentrations of oxalic acid were expressed in g/100 g of dry vegetable drug. Result: The data obtained from the concentration of oxalic acid ranged from 4.58 ± 0.09 g/100 g to 17.21 ± 0.07 g/100 g and demonstrated that the concentrations from acid extraction are higher compared to the aqueous extraction, for all vegetables species analyzed. Methodological optimization was performed for the species that showed the highest results, Psidium guajava and Artocarpus heterophyllus. Conclusion: The data obtained can serve as input for medical decisions and for professionals who prescribe medicinal plants.