Evaluation of Enzyme Inhibition and Anti-Quorum Sensing Potentials of Melaleuca alternifolia and Citrus sinensis Essential Oils

Abstract

In this study, Melaleuca alternifolia (Maiden and Betche) Cheel (tea tree) oil and C. sinensis (L.) Osbeck (orange) oil was procured, and their chemical compositions were characterized by gas chromatography coupled with mass spectrometry, with co-injection using authentic samples. The oils were rich in monoterpene hydrocarbons making up 84.5% of C. sinensis and 48.9% of M. alternifolia oils. High amounts of oxygenated monoterpenoids were also identified in C. sinensis (9.6%) and M. alternifolia (49.3%) oils. The three most abundant compounds were limonene (71.2%), linalool (5.5%), and β-myrcene (5.1%) in C. sinensis, and terpinen-4-ol (45.6%), γ-terpinene (19.4%) and α-terpinene (9.3%) in M. alternifolia. Enzyme inhibitions (anticholinesterase, antiurease, antityrosinase) of both essential oils were evaluated. In acetylcholinesterase assay, M. alternifolia and C. sinensis had inhibition concentration (IC50) values of 153.7 ± 1.25 and 96.4 ± 1.0 µg/mL, respectively as compared to 5.42 ± 0.11 µg/mL for galantamine, while in butyrylcholinesterase assay, M. alternifolia (IC50 = 85.6 ± 0.7 µg/mL) and C. sinensis (IC50 = 127.8 ± 0.6 µg/mL) exhibited moderate activities compared to galantamine (IC50 = 45.8 ± 0.8 µg/mL). In the urease inhibitory activity, essential oils of C. sinensis and M. alternifolia showed 48.4% ± 0.9% and 30.6% ± 0.7% inhibitions at 200 µg/mL concentration, respectively. Quorum sensing (QS) mediated violacein production in Chromobacterium violaceum CV12472 was inhibited by 100% at minimum inhibitory concentration (MIC) values for both oils while showing QS inhibition diameter zones in C. violaceum of 22.5 ± 0.4 mm and 14.3 ± 0.5 mm for C. sinensis and M. alternifolia oils, respectively at MIC concentration. The good quorum-sensing potential indicates that these oils can suppress microbial resistance and severity of infections.

Antibiofilm and Anti-Quorum Sensing Potential of Cycloartane-Type Triterpene Acids from Cameroonian Grassland Propolis: Phenolic Profile and Antioxidant Activity of Crude Extract

“…The effects of natural products on bacterial biofilm result mostly from the inhibition of exopolymeric matrix formation and the suppression of cell adhesion, thereby disrupting the establishment of the extracellular matrix, reducing virulence factors, and blocking quorum sensing communications and growth of the biofilm [ 56 ]. Several natural compounds have shown antibiofilm and anti-quorum sensing activities, and they are promising antimicrobial substances since, in addition to their activities, the natural products extracts, essential oils, and phytochemicals have high efficacy as biofilm inhibitors and anti-quorum sensing agents with greater chemical stability, small molecular weights, and low toxicity to human health [ 9 , 52 , 57 , 58 , 59 , 60 , 61 ]. The results obtained in this study can be further supported by the fact that various bee products such as honey and propolis have been reported to possess good antimicrobial, antibiofilm, and anti-quorum sensing activities against pathogenic bacteria [ 59 , 62 ].…”

Synthesis of cross‐linked diazaborine‐based polymeric microparticles with antiquorum sensing, anti‐swarming, antimicrobial, and antibiofilm properties

“…Pigment production is one of the easiest evidence of quorum sensing which is measurable. The violet coloration produced by C. violaceum CV12472 is violacein, which is an antioxidant molecule that protects the bacterial membrane from oxidative stress and therefore, inhibiting the production of violacein by the synthesized polymeric gels is beneficial effect that can reduce the virulence of the bacteria 40 . The best violacein inhibition was exhibited by the PSPMA‐DAZ and diazaborine‐based polymers have shown violacein inhibition in previous studies 9 .…”

The Effect of Natural Essential Oil Depigmenting Agent for Alternative Treatment of Melasma

“…This compound is the main one because of its antifungal, antiinflammatory, antimicrobial, and antiviral effects [33]. In a study conducted by Alfred Ngenge [34], regarding tea tree essential oil, it was found that the composition of the main compounds in the oil consisted of terpinene-4-ol (45.6%), γ-terpinene (19.4%), α-terpinene (9.3%), 1,8-cineole (5.2%), terpinolene (3.2%), p-cymene (7.6%), dan α-terpineol (3.5%). In addition, the anti-tyrosinase activity of this oil was also measured and the IC50 was 82.3 ± 0.5 g/mL, smaller than the positive control, kojic acid, which was 23.5 ± 0.3 g/mL.…”