In vitro comparison of antioxidant, cytotoxic, and antibacterial (against Aggregatibacter actinomycetemcomitans) effects of Citrus reticulata, Olea europaea extracts, and essential oils

Abstract

Background: This study compared the antioxidant, cytotoxic, and antibacterial effects of Citrus
reticulata (C. reticulata) peel and Olea europaea (O. europaea) leaf hydroalcoholic extracts and
essential oils.
Materials and Methods: In this in vitro study, the antibacterial effect of the C.
reticulata and O. europaea extracts and essential oils was evaluated on Aggregatibacter
actinomycetemcomitans (A. actinomycetemcomitans) by the agar diffusion test. Their minimum inhibitory
concentration (MIC) and minimum bactericidal concentration (MBC) were determined by the
broth microdilution method. Their cytotoxicity against human gingival fibroblasts was evaluated by
the methyl thiazolyl tetrazolium assay in 24 and 72 h, and their antioxidant effect was assessed by
the 2,2‑diphenyl‑1‑picrylhydrazyl assay. Data were analyzed by ANOVA and Tukey’s test (P < 0.05).
Results: The O. europaea hydroalcoholic extract and C. reticulata essential oils had significant
antibacterial effects on A. actinomycetemcomitans. The highest and lowest growth inhibition zones
belonged to C. reticulata essential oils (40.0 ± 0.0 mm) and O. europaea extract (32.3 ± 2.2 mm),
respectively. The MIC and MBC were 0.78 v/v% for O. europaea extract and 6.25% for C. reticulata
essential oils. Unlike the essential oils (1%, 5%, and 10% v/v), none of the extracts showed significant
cytotoxicity at low concentrations (1% v/v). All essential oils and extracts, particularly O. europaea
and C. reticulata extracts, had significant antioxidant effects.
Conclusion: Of the tested materials, O. europaea extract had the highest potential for possible
use as an organic mouthwash due to its strong antibacterial and antioxidant effects and absence
of cytotoxicity in low concentrations.
Key Words: Antibacterial agents, antioxidants, citrus, cytotoxicity, essential oils, immunologic,Olea, plant extracts, volatile

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Seyedeh Zahra Mirsharif: Pubmed,Google Scholar