In vitro antibacterial activities of essential oils and extracts of six herbals against gram-positive and gram-negative bacteria

• Published in: Toxicology and environmental health sciences 2023-03, Vol.15 (1), p.53-60
• Main Authors: Amin, Mansour, Akrami, Sousan, Haghparasty, Farkhondeh, Hakimi, Atiyeh
• Format: Article
• Language: English
• Subjects: Antibacterial activity; Antibiotics; Antimicrobial activity; Antimicrobial agents; Bacteria; Biomedical and Life Sciences; Biomedicine; Chemical composition; Dilution; Distillation; Distillation equipment; Distilled water; Environmental effects; Environmental Health; Essential oils; Gram-negative bacteria; Gram-positive bacteria; Herbal medicine; Medicinal plants; Minimum inhibitory concentration; Oils & fats; Original Article; Pharmacology/Toxicology; Plant extracts; Public health; Synergistic effect
• ISSN: 2005-9752; 2233-7784
• DOI: 10.1007/s13530-022-00160-7

Object Considering the development of bacterial resistance to chemical antibiotics and their adverse effects on the environment and public health, there is a growing demand to replace them with plant-based derivatives or combine these green agents with antibiotics to give synergistic effects. In this study, the antimicrobial properties of essential oils and extracts of six medicinal plants from Ahvaz region, Iran, against 12 gram-positive and gram-negative bacteria were evaluated. Methods The EOs and extracts were extracted using water distillation with Clevenger apparatus. We analyzed the chemical composition of essential oils obtained. The antimicrobial properties and determination of the minimum concentration of growth inhibition of herbals were investigated by the broth dilution technique. Results All analyzed extracts and EOs showed antibacterial effects. The antimicrobial activity of Oliveria decumbens was strongest herbals with the least MIC ranges (0.008–0.1 mg/ml for EO, 0.9–20 mg/ml for extract), while the antibacterial effects of Artemisia vulgaris extract and Glycyrrhiza glabra EO with the highest MIC were weaker than the others. According to the effectiveness of plant extracts on bacteria, Pseudomonas aeruginosa was resistant to all extracts except Oliveria decumbens. In contrast, Bacillus cereus was more sensitive than other strains against analyzed EOs and extracts. In Oliveria decumbens , EO detected 18 components by GC/MS with accessible genuine standards, accounting for 98% of the oil content. Conclusion It seems that due to the antimicrobial properties of the extracts and essential oils observed in this study, they can be used as an alternative to antimicrobial drugs after more extensive studies.