Atividade antioxidante das folhas e flores de Vernonia condensata BAKER (ASTERACEAE) in vitro e in vivo

Abstract

Reactive species, although playing an important role in physiological processes, can lead to oxidative stress when not maintained at adequate levels by antioxidants. This results in the oxidation of biomolecules and cellular damage caused by the excess of these molecules. Oxidative stress, in turn, is associated with the development of various diseases, including those ranked among the leading causes of death worldwide. Consequently, there is a growing search for natural antioxidant compounds to manage oxidative stress effectively. In this context, the plant species Vernonia condensata, commonly known as "boldo-bahiano" and traditionally used to treat gastrointestinal conditions such as ulcers, stands out. Previous studies on this species have explored its chemical composition and biological activities, identifying secondary metabolites from various classes. Its antioxidant, anti-inflammatory, and anticancer effects in vitro have also been described. Thus, the objective of this study was to investigate the chemical composition and antioxidant activity in vitro and in vivo of the aqueous extract from the leaves and flowers of V. condensata. To this end, the phenolic and flavonoid content of the extracts was quantified, their free radical inhibitory effect in vitro was evaluated, and their ability to protect DNA and proteins from oxidation was assessed. In the in vitro assays, phenolic compounds and flavonoids were identified in both extracts, with a higher concentration observed in the flower extract of V. condensata, containing 52.1 mg GAE/100 g of sample for phenolic compounds and 14.38 mg QE/100 g of sample for flavonoids. Additionally, both extracts inhibited free radicals and protected biomolecules from oxidation, with the flower extract demonstrating greater efficacy. Specifically, the flower extract exhibited an IC50 of 28.3 µg/mL against the free radical DPPH• and protected DNA and proteins from oxidation by 83% and 93%, respectively. Based on the in vitro activities, the flower extract of V. condensata was selected for in vivo evaluation using C. elegans as a biotechnological tool for preclinical assays. The in vivo studies showed that, in addition to exhibiting no toxicity in the chosen model, the extract also protected against induced oxidative damage, increasing the viability of treated organisms by up to 13%.Thus, V. condensata emerges as a potential agent for managing oxidative stress due to its chemical composition and the effects observed in both in vitro and in vivo studies.