Análise fitoquímica e avaliação da actividade antioxidante dos extractos do fruto de Tabernaemontana elegans

Abstract

Tabernaemontana elegans belongs to the Apocynaceae family and is used in traditional medicine for the treatment of several diseases, including lung diseases, bacterial and fungal infections. However, few scientific investigations aimed at determining the therapeutic potential of its fruit have been published so far. However, few scientific investigations aimed at determining the therapeutic potential of its fruit have been published so far. Entretanto, poucas investigações científicas visando determinar o potencial terapêutico de seus frutos foram publicadas até o momento. However, few scientific investigations aimed at determining the potential therapeutic results of its fruit have been published so far. No entanto, poucas investigações científicas visando determinar os potenciais resultados terapêuticos de seus frutos foram publicadas até agora. However, few scientific investigations aiming to determine the potential therapeutic treatment of its fruit have been published until then. No entanto, poucas investigações científicas visando determinar o potencial tratamento terapêutico de seus frutos foram publicadas até então. The aim of this study was to evaluate the phytochemical composition and in vitro antioxidant activity of crude hydromethanolic extracts and their respective fractions of n-hexane, chloroform, ethyl acetate, n-butanol and aqueous residue, from the ripe seeds, green peel, ripe peel, green pulp and ripe pulp of the fruit of Tabernaemontana elegans. Qualitative and quantitative phytochemical analyses were performed using standard methods and the antioxidant activity was estimated by assays with 1,1-diphenyl-2-picrylhydrazyl (DPPH), phosphomolybdic acid and ferric ion solution (FRAP). Qualitative analysis revealed the presence of flavonoids and steroids in all parts of the fruit, alkaloids in all except the ripe pulp. GC-MS analysis of the alkaloid fractions identified 18 alkaloids, 9 in the ripe seeds, 6 in the green peel and 3 in the ripe peel. The crude extract of mature seeds showed the highest content of total phenols (46.002 ± 0.327 mgEAG/g) and lipids (429.442 ± 1.856 mgEOS/g), the crude extract of green peel showed the highest content of total flavonoids (26.521 ± 2.027 mgER/g) and alkaloids (27.592 ± 1.590 mgEE/g) and the crude extract of mature pulp showed the highest content of carbohydrates (831.759 ± 3.275 mgEA/g). The crude extract of the green peel showed higher antioxidant activity in the test with 1,1-diphenyl-2-picrylhydrazyl (DPPH) (IC50 = 56.743 ± 0.832 μg/mL) and with ferric ion solution (FRAP) (71.083 ± 2.847 μM Fe2+ equivalents), while the crude extract of the ripe seeds showed higher antioxidant activity in the test with phosphomolybdic acid (16.069 ± 1.387 μg/mL ascorbic acid equivalents). The alkaloid fractions showed higher antioxidant activity in the test with ferric ion solution and with phosphomolybdic acid. The alkaloid fractions also showed a very strong correlation between the alkaloid content and the antioxidant activity in the assay with 1,1-diphenyl-2-picrylhydrazyl and with ferric ion solution. The results suggest that the fruit of T. elegans is promising as a source of antioxidants, which may justify its use in traditional medicine for the treatment of cancer.