
Pharmacokinetics and Tissue Distribution of the Sesquiterpene α-Humulene in Mice
2008; Thieme Medical Publishers (Germany); Volume: 74; Issue: 14 Linguagem: Inglês
10.1055/s-0028-1088307
ISSN1439-0221
AutoresJ. Chaves, Paulo César Leal, Luis Pianowisky, João Β. Calixto,
Tópico(s)Natural product bioactivities and synthesis
ResumoA quantitative study was undertaken to assess the plasma and tissue levels, tissue distribution and skin (ear) absorption of the sesquiterpene α-humulene, the main active constituent isolated from the plant Cordia verbenacea (Boraginaceae), after oral, intravenous and topical administration in mice. The α-humulene levels were quantified by GC-MS analysis. The peak α-humulene concentration was achieved 15 min following its oral administration (150 mg/kg). Then, the α-humulene plasma concentration gradually decreased and it was almost undetectable at 2 hours after intravenous administration and 12 hours after oral administration. When the oil of C. verbenacea was given orally (1 g/kg), the peak α-humulene plasma concentration was observed after 30 min, being detectable only up to 2 h. The oral bioavailability of α-humulene was found to be 18 %. The half-lives of α-humulene were very short, 16.8 min after oral administration and 1.8 min after intravenous administration. However, the elimination half-lives were longer, 118.2 min and 55 min, for oral and intravenous routes, respectively. We also assessed the amount of α-humulene in some selected tissues at 0.5 and at 4 h after oral administration. We found a high amount of the compound in the liver, followed by the kidneys, heart, lungs, spleen and brain, 0.5 h after oral administration. Notably, the yield of α-humulene decreased significantly in all analyzed tissues, especially in the liver, 4 h after oral administration. Of note, 30 minutes after topical administration of Acheflan® formulations (cream and aerosol) containing 0.5 % of C. verbenacea essential oil, a schedule of treatment that produces marked and similar topical anti-inflammatory activity, the amount of α-humulene absorbed in the ear was very similar (about 2 μg/ear). It is concluded that α-humulene exhibited a rapid onset and relatively good absorption following oral and topical administration. Taken together, these findings further contribute to an explanation of the topical and systemic anti-inflammatory and antinociceptive properties previously reported for the essential oil and for α-humulene obtained from Cordia verbenacea, they also provide support for the clinical studies conducted with the phytomedicine Acheflan®.
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