Chemical Constituents, Antioxidant and Antimicrobial Activity of Syzygium aromaticum

Abstract

Phenolic constituents from residue after clove oil extraction and oil on oral micro-biota causing dental caries werestudied. Both clove oil and extract were found to exhibit broad spectrum of antibacterial activity inhibiting all the ten testbacterial species involved in dental caries. Clove oil produced inhibition zone of diameter (IZD) of 19.0, 19.0, 18.0, 17.0 and 15.0 mm against Halobacterium sp., Lactobacillus sp., Pseudomonas sp., Micrococcus sp. and Streptococcus mutans, respectively as compared to extract from residue (15.0, 14.0, 16.0, 15.0 and 13.0mm). The inhibitory effect was concentrationdependent and has the potential to be used as a natural antibacterial agent. The antifungal activity of oil and extractassessed against seven fungal species (Aspergillus niger, A. fumigatus, Aspergillus sp., Alternaria sp., Rhizomucor sp., Rhizopus sp. and Penecillium sp.) and both were able to inhibit the test fungal strains but clove oil was superior in efficacy. The highest IZD 42.0mm was observed against A. niger by oil while extract produced IZD 30.0mm against Alternaria sp. The chemical constituents of clove oil analyzed by GC-MS showed 35 constituents with major ingredients as eugenol (81.6%), eugenyl acetate (5.2%), -caryophyllene (2.3%) and as minor β-farnesene (0.98%), β-phellandrene (0.74%), linalool (0.73%) and γ-Terpinene (0.69%). Phenolic compounds identified from extract of residue left after oil extraction were biflorin, kaempferol, rhamnocitrin, myricetin, gallic acid and ellagic acid. The free radical quenching antioxidant activity varied from 75.8 to 89.6% and was comparable to synthetic antioxidants (BHT and BHA).