Phenolic compounds from kenaf (Hibiscus cannabinus L.) seeds by ultrasound-assisted extraction

There is great interest in the replacement of synthetic antioxidants with natural sources, especially from plant materials. Kenaf seed potentially contained phenolic compounds. Kenaf seed extract (KSE) was extracted by ultrasonic-assisted extraction. Then, the purification was carried out using silica gel column chromatography. Finally, the phenolic compounds were determined by high-performance liquid chromatography. There were 11 phenolic acids identified from the purified KSE, which were identified as sinapic acid (3563.67 mg/100 g), ferulic acid (2085.55 mg/100 g), catechin hydrate (1189.02 mg/100 g), tannic acid (1032.24 mg/100 g), naringin (385.75 mg/100 g), 4-hydroxybenzoic acid (382.51 mg/100 g), gallic acid (380.18 mg/100 g), 4-hydroxybenzaldehyde (372.00 mg/100 g), protocatehuic acid (207.04 mg/100 g), syringic acid (189.13 mg/100 g), and cinnamic acid (85.51 mg/100 g). The KSE was found to exhibit an antioxidant capability, and it is potentially suitable to be used as an alternative source of antioxidants.