Antioxidant potential of Gossypium hirsutum L. (Malvaceae) using DPPH, ferric reducing antioxidant power, β-carotene bleaching and bioautography assays

Abstract

Gossypium hirsutum L. (Malvaceae), known as “cotton”, is used to treat inflammation, cutaneous lesions, infections, hemorrhages, and other disturbs [1,2]. These disorders are related with oxidative stress and consequent cellular damage. Moreover, G. hirsutum contains phytochemical constituents that are free radical scavengers, and inhibitors of lipid peroxidation processes [3,4]. In this context, the present study investigated the antioxidant potential of the ethanol extract (EE) and hexane (HF), dichloromethane (DF), ethyl acetate (AF), and butanol (BF) fractions from G. hirsutum leaves. The antioxidant potential was assessed by 2,2-diphenyl-1-picrylhydrazyl (DPPH), ferric reducing antioxidant power (FRAP), β-carotene bleaching and bioautography assays. The data were expressed as mean ± S.E.M (p < 0.05). The EC50 values (µg/mL) for DPPH and FRAP assays were, respectively: rutin (9.62 ± 0.28 and 8.1 ± 0.54), EE (70.97 ± 1.53 and 55.44 ± 2.8), HF (213.38 ± 2.94 and 164.73 ± 2.34), DF (83.43 ± 2.94 and 109.42 ± 0.51), AF (24.99 ± 0.16 and 24.37 ± 2.18) and BF (52.28 ± 3.07 and 57.33 ± 1.92). In the β-carotene bleaching assay, the percentage inhibition (%I) was: EE = 51.02 ± 1.92; HF = 82.17 ± 1.62; DF = 71.21 ± 1.07; AF = 73.65 ± 0.75 and BF = 42.97± 2.58. EE and fractions showed higher %I than rutin (5.82 ± 0.81), while EE and BF produced lower values than quercetin (64.08 ± 2.13). The bioautography data revealed that the antioxidant effect is due the presence of phenolic compounds, particularly flavonoids. These results suggest that G. hirsutum is an important and promising source of bioactive molecules with antioxidant action.