Nanotechnology in Phytotherapy: Antiinflammatory Effect of a Nanostructured Thymol Gel from Lippia sidoides in Acute Periodontitis in Rats.

Lippia sidoides Cham (Verbenaceae) is largely distributed in the northeastern region of Brazil. It is popularly known as 'Alecrim-pimenta'. Recent studies have shown that some species of Lippia have interesting pharmacological activities. This study aimed to evaluate the effect of a nanostructured thymol gel (TG) 1.2 mg/g on acute phase of ligature-induced periodontitis model [acute periodontal disease (APD)] in rats. APD was induced in 24 Wistar rats subjected to ligature placement on left molars in maxillae. Animals were treated with TG, immediately after APD induction. Saline-based gel was utilized as negative control and diethylammonium diclofenac gel 10 mg/g was used as positive control. Animals were randomly assigned into the groups. The periodontium and the surrounding gingiva were examined at histopathology, as well as the neutrophil influx into the gingiva was assayed using myeloperoxidase activity levels by ELISA method. TG treatment reduced tissue lesion at histopathology coupled to decreased myeloperoxidase activity production in gingival tissue when compared with the saline gel control group (p < 0.05). The TG gel was able to provide a significant myeloperoxidase decreasing in gingiva tissue confirming to be effective in reducing gingival inflammation in this model.

Hyptis pectinata gel prevents alveolar bone resorption in experimental periodontitis in rats

Hyptis pectinata (L.) Poit., Lamiaceae, is an aromatic, abundant and broadly used plant species in Sergipe to treat oral and gastrointestinal pain and inflammation. The aim of the present study was to analyze the relation between periodontitis and changes in the corporal mass and alveolar bone structure after induction of experimental periodontal disease in rat treated or not treated with H. pectinata gel at 5% (GS5%) and 10% (GS10%), comparing their effects with doxycycline gel at 10% (D10%, positive control), vehicle gel (negative control) and a group with experimental periodontal disease, but non-treated. The gels were locally applied in the gingival region immediately after the experimental periodontal disease induction by ligature (3×/day, 11 days). Bone destruction was determined through clinical exam, histopathological analysis and cone beam computed tomography of the experimental animals (n = 36). After 11 days of periodontitis induction, all groups that received ligature presented a decrease in the corporal mass, except to the naïve group (without experimental periodontal disease) (p < 0.05). Computed tomography results have shown healthy bone structure in the group I and bone resorption for the test groups. Histopathological analysis confirmed the healthy bone structure for naïve group animals, while the test groups exhibited bone loss in several degrees. In particular, the non-treated group animals had an intense inflammatory process. When the periodontium of the animals treated with GS10% was histopathologically analyzed, insertion periodontium was preserved. The results for these groups were significantly different of the vehicle group (p < 0.05). According to the results, the gel based in the aqueous extract of H. pectinata at 10% can prevent bone loss in experimental periodontal disease similarly to doxycycline 10%.

Topical antiinflammatory activity of essential oil of Lippia sidoides cham: possible mechanism of action.

This work reports the chemical composition of the essential oil of Lippia sidoides (EOLS) and evaluation of the topical effect of EOLS and thymol against different irritant agents in vivo. The essential oil was obtained by hydrodistillation, and gas chromatography/mass spectrometry analysis identified the main constituents: thymol (84.9%) and p-cymene (5.33%). The antiinflammatory activity was evaluated using the mouse models of acute ear inflammation induced by croton oil, arachidonic acid, phenol or histamine, and chronic inflammation induced by croton oil. The topical application of EOLS or thymol at a dose of 2 mg/ear significantly reduced (p < 0.001) ear edema induced with arachidonic acid by 45.1% and 47.4% and reduced ear edema induced with phenol by 33.2% (p < 0.05) and 54.7% (p < 0.01) in acute ear edema. However, a proinflammatory effect of EOLS and thymol was evidenced when it was applied for more than 1 day. There were no statistical differences in antiedematogenic activity between EOLS and thymol. In conclusion, the results indicate that thymol is the constituent responsible for the topical antiinflammatory activity of EOLS. Thus, these findings could justify the popular use of L. sidoides by alternative medicine, but chronic use has an inflammatory effect.

Synergistic antibiotic activity of volatile compounds from the essential oil of Lippia sidoides and thymol.

Lippia sidoides Cham. (Verbenaceae) is used in the folk medicine as topical antiseptic in skin and mucous membranes and its therapeutic effect is attributed to the thymol presence. The objective of this work was to verify the chemical composition and antibiotic modifying activity of the essential oil extracted from the leaves of L. sidoides and its major component thymol. The essential oil was obtained by hydrodistillation and analyzed by GC/MS. The synergistic activity was evaluated using gaseous contact method. The essential oil was obtained (yield of 1.06%) and the GC/MS analysis identified the main constituents: thymol (84.9%) and p-cymene (5.33%). The antibiotic modifying activity was verified using the minimal inhibitory dose method and gaseous contact. It verified the interference of essential oil and thymol against all tested aminoglycosides. There were no statistical differences between the activity of the essential oil and thymol against Pseudomonas aeruginosa, indicating this to be the responsible composition for such activity. However, the oil was shown more effective when compared to the thymol against Staphylococcus aureus. The essential oil of L. sidoides and its major component thymol influence the activity of aminoglycosides and may be used as adjuvant in antibiotic therapy against respiratory tract bacterial pathogens.

Citral reduces nociceptive and inflammatory response in rodents

Citral (CIT), which contains the chiral enantiomers, neral (cis) and geranial (trans), is the majority monoterpene from Lippia alba and Cymbopogon citratus. The present study aimed to evaluate CIT for antinociceptive and anti-inflammatory activities in rodents. Antinociceptive and anti-inflammatory effects were studied by measuring nociception through acetic acid and formalin tests, while inflammation was verified by inducing peritonitis and paw edema with carrageenan. All tested doses of CIT had significant protection (p<0.001) against acetic acid (0.8 percent) induced nociceptive behavior and the effects were also similar to morphine while formalin induced nociception was significantly protected (p<0.05) only at higher dose (200 mg/kg) of CIT in the first phase of the test. CIT significantly reduce (p<0.001) nociceptive behavior emanating from inflammation in second phase at all the doses.The pretreatment with CIT (100 and 200 mg/kg) significantly reduced the paw edema induced by carrageenan. Moreover, systemic treatment with CIT (100 and 200 mg/kg) significantly reduced (p<0.001) the leukocyte migration in the carrageenan-induced migration to the peritoneal cavity. Our investigation shows that CIT possess significant central and peripheral antinociceptive effects. It was also verified an anti-inflammatory activity. All together these results suggest that CIT might represent important tool for treatment of painful conditions.

Enhancement of the antibiotic activity of erythromycin by volatile compounds of Lippia alba (Mill.) N.E. Brown against Staphylococcus aureus.

BACKGROUND: Lippia alba (Mill.) N.E. Brown, popularly known as "erva-cidreira," is commonly found in northeastern Brazil. The leaves tea is used to treat digestive disturbances, nausea, cough, and bronchitis. OBJECTIVE: This work reports the chemical composition and erythromycin-modifying activity by gaseous contact against Staphylococcus aureus. MATERIALS AND METHODS: The leaves of L. alba were subjected to hydrodistillation, and the essential oil extracted was examined with respect to the chemical composition, by gas chromatography-mass spectrometry (GC-MS), and the essential oil extracted was evaluated for antibacterial and antibiotic-modifying activity by gaseous contact. RESULTS: The overall yield of essential oil obtained by hydrodistillation was 0.52%. The GC-MS analysis has led to the identification of the main components: geranial (31.4%) and neral (29.5%). It was verified that the essential oil interfered with erythromycin antibiotic activity against S. aureus ATCC 25923 was enhanced (221.4%) in the presence of 12% essential oil. The 3% essential oil increased the effect against S. aureus ATCC 25923 (41.6%) and S. aureus ATCC 6538 (58.3%). CONCLUSION: The essential oil of L. alba influences the activity of erythromycin and may be used as an adjuvant in antibiotic therapy against respiratory tract bacterial pathogens. CONCLUSION: The essential oil of L. alba influences the activity of erythromycin and may be used as an adjuvant in antibiotic therapy against respiratory tract bacterial pathogens.