Chemical Composition, Anti-Quorum Sensing, Enzyme Inhibitory, and Antioxidant Properties of Phenolic Extracts of Clinopodium nepeta L. Kuntze

Abstract

Phenolic extracts of Clinopodium nepeta were prepared and their preliminary phenolic profiles determined using HPLC-DAD with 26 phenolic standards. Apigenin (21.75 ± 0.41 µg/g), myricetin (72.58 ± 0.57 µg/g), and rosmarinic acid (88.51 ± 0.55 µg/g) were the most abundant compounds in DCM (dichloromethane), AcOEt (ethyl acetate), and BuOH (butanol) extracts, respectively. The DCM and AcOEt extracts inhibited quorum-sensing mediated violacein production by C. violaceum CV12472. Anti-quorum-sensing zones on C. violaceum CV026 at MIC (minimal inhibitory concentration) were 10.3 ± 0.8 mm for DCM extract and 12.0 ± 0.5 mm for AcOEt extract. Extracts showed concentration-dependent inhibition of swarming motility on flagellated P. aeruginosa PA01 and at the highest test concentration of 100 μg/mL, AcOEt (35.42 ± 1.00%) extract displayed the best activity. FRAP assay indicated that the BuOH extract (A0.50 = 17.42 ± 0.25 µg/mL) was more active than standard α-tocopherol (A0.50 = 34.93 ± 2.38 µg/mL). BuOH extract was more active than other extracts except in the ABTS●+, where the DCM extract was most active. This antioxidant activity could be attributed to the phenolic compounds detected. C. nepeta extracts showed moderate inhibition on acetylcholinesterase (AChE), butyrylcholinesterase (BChE), tyrosinase, and α-amylase. The results indicate that C. nepeta is a potent source of natural antioxidants that could be used in managing microbial resistance and Alzheimer′s disease.

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

“…Quorum sensing involves a cell–cell communication process in bacteria through the secretion, detection, and response to extracellular signaling molecules, which enable the bacterial community to monitor information about the environment, population, and cell numbers and collectively alter their gene expression, helping them to act in synchrony [ 63 ]. This accounts for the virulence factors, biofilms, and severity during infections; therefore, it will be beneficial to inhibit and disrupt quorum sensing networks in pathogenic bacteria, especially with the use of natural medicinal plants and their compounds and essential oils [ 9 , 64 , 65 ]. The propolis sample and the isolated pentacyclic triterpenoids inhibited violacein production and quorum sensing in C. violaceum CV12472 and C. violaceum CV026, respectively, indicating that they can reduce bacterial cell-to-cell communication networks.…”

First contribution to the ethnobotanical knowledge in the Peloritani Mounts (NE Sicily)

“…nepeta, a hemicryptophyte rich in essential oils [68,69], it is well known as an antiseptic in folk medicine, especially against insect bites, for example bees and hornets [70,71]. These medicinal properties are confirmed by many studies that highlighted its chemical composition [72,73]. Another one is Dittrichia viscosa subsp.…”

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

“…In the present study, synthesized spherical polymer microparticles are used as a promising antibiotic agent capable of disrupting quorum‐sensing networks in bacteria and reducing their pathogenicity. Quorum‐sensing mediated processes involve cell‐to‐cell communication networks within microbial colonies using small signal molecules (which can be oligopeptides, acylhomoserine lactone or furan borate diesters) when they attain a threshold concentration, and intervenes in formation of biofilms, movements, virulence gene expression, pigment production, resistance to antibiotics, toxin production, survival and proliferation of microbes 37–39 . Pigment production is one of the easiest evidence of quorum sensing which is measurable.…”

“…Quorum-sensing mediated processes involve cell-to-cell communication networks within microbial colonies using small signal molecules (which can be oligopeptides, acylhomoserine lactone or furan borate diesters) when they attain a threshold concentration, and intervenes in formation of biofilms, movements, virulence gene expression, pigment production, resistance to antibiotics, toxin production, survival and proliferation of microbes. [37][38][39] 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.…”