Chemical Composition, Phytotoxic, Antimicrobial and Insecticidal Activity of the Essential Oils of Dracocephalum integrifolium

Abstract

The present investigation studied the chemical composition of the essential oils extracted from Dracocephalum integrifolium Bunge growing in three different localities in northwest China and evaluated the phytotoxic, antimicrobial and insecticidal activities of the essential oils as well as their major constituents, i.e., sabinene and eucalyptol. GC/MS analysis revealed the presence of 21–24 compounds in the essential oils, representing 94.17–97.71% of the entire oils. Monoterpenes were the most abundant substances, accounting for 85.30–93.61% of the oils; among them, sabinene (7.35–14.0%) and eucalyptol (53.56–76.11%) were dominant in all three oils, which occupied 67.56–83.46% of the total oils. In general, phytotoxic bioassays indicated that the IC50 values of the oils and their major constituents were below 2 μL/mL (1.739–1.886 mg/mL) against Amaranthus retroflexus and Poa annua. Disc diffusion method demonstrated that the oils and their major constituents possessed antimicrobial activity against Bacillus subtilis, Pseudomonas aeruginosa, Escherichia coli, Saccharomyces cerevisiae, and Candida albicans, with MIC values ranging from 5–40 μL/mL (4.347–37.712 mg/mL). The oils, sabinene and eucalyptol also exhibited significant pesticidal activity, with the mortality rates of Aphis pomi reaching 100% after exposing to 10 μL oil/petri dish (8.694–9.428 mg/petri dish) for 24 h. To the best of our knowledge, this is the first report on the chemical composition, phytotoxic, antimicrobial and insecticidal activity of the essential oils extracted from D. integrifolium; it is noteworthy to mention that this is also the first report on the phytotoxicity of one of the major constituents, sabinene. Our results imply that D. integrifolium oils and sabinene have the potential value of being further exploited as natural pesticides.

Multifunctional Hydroxyapatite Coated with Arthemisia absinthium Composites

“…Furthermore, the HApWW samples also exhibited a higher BET surface area compared with HAp samples, and higher particle size according to TEM results. These results are in agreement with previously reported studies [55][56][57] and clearly suggest that the antimicrobial activity of the HApWW samples are a consequence of multiple factors such as their sizes, surface area, roughness, active antimicrobial substances and also the cell morphology of the tested microorganisms. The results obtained from the GC-MS analysis revealed that WW EO is mainly constituted of monoterpenes.…”

“…Considering their properties and their chemical structure, one of the proposed mechanism in the forming of HApWW samples would be through hydrogen bonding and/or dipole interactions. Furthermore, the antimicrobial activity presented by the WW and HApWW samples is strongly correlated with the presence of the major constituents α-Fenchene, Sabinene, β-Thujene, β-myrcene and methyl salicylate, which were reported to possess good antimicrobial activity against microbial strains such as E. coli, B. subtillis, P. aeruginosa, S. cerevisiae and C. albicans [57]. Moreover, the studies reported by Ghaffari et al [58] regarding EOs having most abundant chemical constituents β-pinene, β-myrcene, limonene, and caryophyllene also demonstrated antimicrobial activity against some highly susceptible strains such as E. coli, C. albicans, and S. aureus.…”

Cell death and biomass reduction in biofilms of multidrug resistant extended spectrum β-lactamase-producing uropathogenic Escherichia coli isolates by 1,8-cineole

“…At the minimum inhibitory concentration (MIC) [0.8% (v/v)], 1,8-cineole showed bactericidal effect on planktonic E. coli cells, with membrane disruption as the bactericidal mechanism identified. Other authors reported MICs of 1,8-cineole for E. coli strains � 0.8% (v/v) [13][14][15]. Nevertheless, the effect of this phytochemical on E. coli biofilms has not been extensively explored.…”

Antifungal Activity and Synergistic Effect of Essential oil from Lippia alba Against Trichophyton rubrum and Candida spp.

“…The antifungal activity of sabinene 29 and limonene 30 against Saccharomyces cerevisiae, Candida spp., Cryptococcus neoformans, and Malassezia furfur has been reported. Deena and Thoppil 31 investigated the antibacterial activity of the essential oil from L. camara collected in Calicut, India.…”