Avaliação de perfil químico e atividade biológica de extratos de cravo-da-índia obtidos por diferentes métodos

Abstract

The use of certain food additives might cause negative changes in the properties of food and an alternative for this is the use of bioadditives, which do not cause direct impacts to the food and their use may suggest health benefits. An example of bioadditives are essential oils, whose antifungal and antibacterial properties are well known. Plant extracts also stand out as an alternative to the use of certain additives. Clove (Syzygium aromaticum) is known for its antifungal and antibacterial activities. The main objective of this work was to evaluate the biological activity of clove essential oil and extracts, obtained by different extraction methods. A single batch of dried clove buds was used. The clove essential oil was obtained by hydrodistillation and the extracts were obtained by maceration, ultrasound-assisted extraction at 25 oC and ultrasound-assisted extraction at 40 oC. The chemical profile analysis of clove extracts demonstrated the presence of classes of compounds of gallic acid, flavones and their isomers. Gallic acid, theobromine and myricetin were quantified with values between 413,53 and 798,58 μg/mL, 0,0030 and 0,005 μg/mL and 0,031 and 0,040 μg/mL, respectively. In order to determine the biological activity, strains of E. coli, L. monocytogenes, S. enteritidis and S. aureus were used. The antimicrobial activity was verified by the formation or absence of inhibition halos (mm) around the holes made in Petri dishes containing TSA. The chemical profile analysis was conducted in a liquid phase chromatograph coupled to a UFLC diode array detector. The antioxidant activity was measured by the DPPH method, as described by Mensor et al. (2001). The yield of the essential oil extraction process was 1,05%. The extracts obtained using ultrasound and by maceration process yielded between 1,45 e 7,74%. For the concentration of 100 μL/mL, the oil samples, U(25 oC)30', U(25 oC)30', U(40 oC)15' and U(40 oC)30' presented the largest halos of inhibition for S. enteritidis, between 2,40 and 2,92 mm. For S. aureus, the samples U(25 oC)30’, U(40 oC)15’ and U(40 oC)30’ presented the highest values, between 2,05 and 2,55 mm. The samples U(40 oC)15’ and U(40 oC)30’ showed the largest inhibition halos for E. coli, between 2,60 and 2,67 mm. For L. monocytogenes, the samples U(40 oC)15’ and U(40 oC)30’ presented the highest values, between 1,88 and 2,15 mm. For the concentration of 50 μL/mL, the sample with the highest antimicrobial activity was the essential oil. The total phenolic content found was between 0,101 and 0,290 mg GEA/gext, with the highest values observed in extracts obtained by ultrasound-assisted extraction. The results of the antioxidant activities DPPH (% AA) ranged between 8,15 and 65,24%. The highest values observed were from essential oil samples and extracts obtained by ultrasound-assisted extraction. This work demonstrated that clove essential oil and extracts, obtained by different extraction methods, have biological activity, which may arouse interest in the food and pharmaceutical industries.