Determinação de atividade antioxidante do óleo essencial de guavira (Campomanesia sp.) por diferentes metodologias

Abstract

Brazil, due to its ample biodiversity, stands out as a potential for natural products. The cerrado biome occupies 23% of the national territory and is rich in genera, including 14 of the 36 species of the genus Campomanesia. The guavira, as it is known, is consumed raw, and its peels and seeds are discarded. These residues are sources of nutrients and bioactive compounds, from which it is possible to extract the essential oil (EO), with proven biological activity, due to the presence of terpenes, highlighting the antioxidant activity. The antioxidants present in essential oils are of importance to the food industry to prevent lipid oxidation of various products, using natural sources instead of synthetic additives. The usual methodologies in scientific articles are the in vitro methods, free radical scavenger, by spectrophotometry and being compared to an antioxidant with recognized activity. The present study aims to characterize, by the ABTS, DPPH and FRAP methodologies, the antioxidant activity of the essential oil extracted from the waste peels and seeds of Campomanesia sp. and to adapt a protocol for determining the antioxidant activity of essential oils. The essential oil was obtained by hydrodistillation, chemical composition was evaluated by chromatographic analysis using a gas chromatograph coupled to a mass spectrum; antioxidant activity was evaluated in vitro by spectrophotometry and positive controls butylhydroxytoluene and ascorbic acid, and Trolox and ferrous sulfate were used for analytical curves. The yield of oil obtained by hydrodistillation was 0.35% v/m. The majority components found were α-pinene (16.93%), limonene (16.70%), β- ocimene (10.58%), and β-caryophyllene (9.17%). The antioxidant activity results of EO by ABTS method was 7.5291 μmol TE/g EO and FRAP was 393.2474 μmol FeSO4/g; in IC50 results were 24.834 mg/mL by ABTS method, 0.5827 mg/mL by FRAP method and 41.1389 mg/mL for DPPH method. Antioxidant activity results were obtained by all three methods, with DPPH being poorly indicated due to its poor applicability for lipophilic samples. The ABTS protocol obtained good results for essential oil.