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Essential oil of Lippia alba and its main constituent citral block the excitability of rat sciatic nerves.

Sousa DG, Sousa SD, Silva RE, Silva-Alves KS, Ferreira-da-Silva FW, Kerntopf MR, Menezes IR, Leal-Cardoso JH, Barbosa R - Braz. J. Med. Biol. Res. (2015)

Bottom Line: Peak-to-peak amplitude of the CAP was significantly reduced by 30 µg/mL EOLa and 10 µg/mL citral.Both EOLa and citral showed inhibitory actions at lower concentrations compared with other essential oils and constituents with local anesthetic activity.In conclusion, these data demonstrate that EOLa and citral are promising agents in the development of new drugs with local anesthetic activity.

View Article: PubMed Central - PubMed

Affiliation: Laboratório de Fisiofarmacologia das Células Excitáveis, Universidade Regional do Cariri, Crato, CE, Brasil.

ABSTRACT
Lippia alba is empirically used for infusions, teas, macerates, and hydroalcoholic extracts because of its antispasmodic, analgesic, sedative, and anxiolytic effects. Citral is a mixture of trans-geranial and cis-neral and is the main constituent of L. alba essential oil and possesses analgesic, anxiolytic, anticonvulsant, and sedative effects. The present study evaluated the effects of the essential oil of L. alba (EOLa) and citral on compound action potentials (CAPs) in Wistar rat sciatic nerves. Both drugs inhibited CAP in a concentration-dependent manner. The calculated half-maximal inhibitory concentrations (IC50) of peak-to-peak amplitude were 53.2 µg/mL and 35.00 µg/mL (or 230 µM) for EOLa and citral, respectively. Peak-to-peak amplitude of the CAP was significantly reduced by 30 µg/mL EOLa and 10 µg/mL citral. EOLa and citral (at 60 and 30 µg/mL, values close to their respective IC50 for CAP blockade) significantly increased chronaxy and rheobase. The conduction velocity of the first and second CAP components was statistically reduced to ∼86% of control with 10 µg/mL EOLa and ∼90% of control with 3 µg/mL citral. This study showed that EOLa inhibited nerve excitability and this effect can be explained by the presence of citral in its composition. Both EOLa and citral showed inhibitory actions at lower concentrations compared with other essential oils and constituents with local anesthetic activity. In conclusion, these data demonstrate that EOLa and citral are promising agents in the development of new drugs with local anesthetic activity.

No MeSH data available.


Related in: MedlinePlus

Representative traces and data of rat sciatic nerve compound action potentials(CAP) in control, essential oil of Lippia alba (EOLa) and citralgroups. Panel A: left traces indicate CAP in control group;center traces indicate nerve exposed to 60 µg/mL EOLa and 60 µg/mL citral; andright traces indicate the recovery period. Concentration-dependent curves for EOLaand citral on peak-to-peak amplitude of CAP are shown in panel B.Panels C and D show the time course ofconduction velocities of the first and second CAP components upon exposure toEOLa. Panels E and F show the effects of citralon conduction velocity time course. P<0.05, *EOLa and #citralcompared to control (ANOVA or paired t-test).
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f01: Representative traces and data of rat sciatic nerve compound action potentials(CAP) in control, essential oil of Lippia alba (EOLa) and citralgroups. Panel A: left traces indicate CAP in control group;center traces indicate nerve exposed to 60 µg/mL EOLa and 60 µg/mL citral; andright traces indicate the recovery period. Concentration-dependent curves for EOLaand citral on peak-to-peak amplitude of CAP are shown in panel B.Panels C and D show the time course ofconduction velocities of the first and second CAP components upon exposure toEOLa. Panels E and F show the effects of citralon conduction velocity time course. P<0.05, *EOLa and #citralcompared to control (ANOVA or paired t-test).

Mentions: Figure 1 shows the two CAP components of sciaticnerves at the end of the stabilization period (left traces). When applied to the sciaticnerve, EOLa and citral (60 and 30 µg/mL, respectively) progressively blocked theamplitude of CAP waves during 180 min of drug exposure (Figure 1A and B) reaching 50% of PPA (center traces). Removal and replacementof EOLa and citral solutions with Locke's solution promoted the recovery of CAPcomponents similar to the control traces (right traces).


Essential oil of Lippia alba and its main constituent citral block the excitability of rat sciatic nerves.

Sousa DG, Sousa SD, Silva RE, Silva-Alves KS, Ferreira-da-Silva FW, Kerntopf MR, Menezes IR, Leal-Cardoso JH, Barbosa R - Braz. J. Med. Biol. Res. (2015)

Representative traces and data of rat sciatic nerve compound action potentials(CAP) in control, essential oil of Lippia alba (EOLa) and citralgroups. Panel A: left traces indicate CAP in control group;center traces indicate nerve exposed to 60 µg/mL EOLa and 60 µg/mL citral; andright traces indicate the recovery period. Concentration-dependent curves for EOLaand citral on peak-to-peak amplitude of CAP are shown in panel B.Panels C and D show the time course ofconduction velocities of the first and second CAP components upon exposure toEOLa. Panels E and F show the effects of citralon conduction velocity time course. P<0.05, *EOLa and #citralcompared to control (ANOVA or paired t-test).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4541688&req=5

f01: Representative traces and data of rat sciatic nerve compound action potentials(CAP) in control, essential oil of Lippia alba (EOLa) and citralgroups. Panel A: left traces indicate CAP in control group;center traces indicate nerve exposed to 60 µg/mL EOLa and 60 µg/mL citral; andright traces indicate the recovery period. Concentration-dependent curves for EOLaand citral on peak-to-peak amplitude of CAP are shown in panel B.Panels C and D show the time course ofconduction velocities of the first and second CAP components upon exposure toEOLa. Panels E and F show the effects of citralon conduction velocity time course. P<0.05, *EOLa and #citralcompared to control (ANOVA or paired t-test).
Mentions: Figure 1 shows the two CAP components of sciaticnerves at the end of the stabilization period (left traces). When applied to the sciaticnerve, EOLa and citral (60 and 30 µg/mL, respectively) progressively blocked theamplitude of CAP waves during 180 min of drug exposure (Figure 1A and B) reaching 50% of PPA (center traces). Removal and replacementof EOLa and citral solutions with Locke's solution promoted the recovery of CAPcomponents similar to the control traces (right traces).

Bottom Line: Peak-to-peak amplitude of the CAP was significantly reduced by 30 µg/mL EOLa and 10 µg/mL citral.Both EOLa and citral showed inhibitory actions at lower concentrations compared with other essential oils and constituents with local anesthetic activity.In conclusion, these data demonstrate that EOLa and citral are promising agents in the development of new drugs with local anesthetic activity.

View Article: PubMed Central - PubMed

Affiliation: Laboratório de Fisiofarmacologia das Células Excitáveis, Universidade Regional do Cariri, Crato, CE, Brasil.

ABSTRACT
Lippia alba is empirically used for infusions, teas, macerates, and hydroalcoholic extracts because of its antispasmodic, analgesic, sedative, and anxiolytic effects. Citral is a mixture of trans-geranial and cis-neral and is the main constituent of L. alba essential oil and possesses analgesic, anxiolytic, anticonvulsant, and sedative effects. The present study evaluated the effects of the essential oil of L. alba (EOLa) and citral on compound action potentials (CAPs) in Wistar rat sciatic nerves. Both drugs inhibited CAP in a concentration-dependent manner. The calculated half-maximal inhibitory concentrations (IC50) of peak-to-peak amplitude were 53.2 µg/mL and 35.00 µg/mL (or 230 µM) for EOLa and citral, respectively. Peak-to-peak amplitude of the CAP was significantly reduced by 30 µg/mL EOLa and 10 µg/mL citral. EOLa and citral (at 60 and 30 µg/mL, values close to their respective IC50 for CAP blockade) significantly increased chronaxy and rheobase. The conduction velocity of the first and second CAP components was statistically reduced to ∼86% of control with 10 µg/mL EOLa and ∼90% of control with 3 µg/mL citral. This study showed that EOLa inhibited nerve excitability and this effect can be explained by the presence of citral in its composition. Both EOLa and citral showed inhibitory actions at lower concentrations compared with other essential oils and constituents with local anesthetic activity. In conclusion, these data demonstrate that EOLa and citral are promising agents in the development of new drugs with local anesthetic activity.

No MeSH data available.


Related in: MedlinePlus