Chemical composition, antioxidant and bioactivities of essential oils from Melaleuca bracteata leaves

Abstract

Melaleuca bracteata possesses antioxidant, antibacterial, and herbicidal activities. However, the agricultural applications of M. bracteata have not been explored yet. The M. bracteata leaves were distilled, and the petroleum ether extract of the essential oils (PEEO) was analysed by GC-MS, where methyl eugenol was found to be the most abundant (66.68%). The total polyphenol content (TPC), the total flavonoids content (TFC) of the PEEO were 6.617 ± 0.535 mg gallic acid equivalents/g and 7.086 ± 0.452 mg rutin equivalents/g, respectively. The IC₅₀ values of the DPPH, ABTS and Fe³⁺ were 4.180 ± 0.050 mg/ml, 5.400 ± 0.140 mg/ml, and 8.935 ± 0.067 mg/g, respectively. The EC₅₀ value of the PEEO was 33.78 ± 2.35 μg/ml against the Pyricularia oryzae. The minimum inhibitory concentration and minimum bactericidal concentration values were 0.10 mg/ml and 0.45 mg/ml against Bacillus subtilis. The results indicate that M. bracteata PEEO possesses excellent antioxidant activities and bioactivities.