Anesthetic Pharmacology of the Mint Extracts L-Carvone and Methyl Salicylate

Analgesic effect of the mint terpenoid L-carvone in sheep

OBJECTIVE

To determine whether L-carvone increases the voltage threshold response to a noxious electrical stimulus in sheep.

STUDY DESIGN

Prospective, blinded, randomized, crossover experimental study.

ANIMALS

A group of six healthy adult sheep.

METHODS

Sheep were instrumented with cranial dorsothoracic subcutaneous copper electrodes. A stimulator delivered a 10 ms square-wave stimulus at 50 pps starting at 0.1 V with a 0.2 V second-1 ramp. The stimulus stopped once two observers who were blinded to treatment noted a behavioral pain response or when a 15 V cut-off was reached. Next, 0.15 mL kg-1 of either a 50% L-carvone solution or a saline-vehicle control was administered intramuscularly, and electrical threshold responses were measured every 5-15 minutes over a 6 hour period using methods identical to the baseline. One week following the first treatment (L-carvone or control), sheep were studied using identical methods with the second treatment (control or L-carvone). Drug and time effects were evaluated using a two-way repeated measures analysis of variance, and pairwise comparisons were evaluated with Holm-Sidák tests with values of p < 0.05 considered significant.

RESULTS

L-carvone significantly increased voltage threshold responses for most time points up to 75 minutes compared with baseline and with saline control. The last time point with a significantly different response between L-carvone and saline treatments was 5 hours after drug administration. The saline-vehicle control decreased voltage threshold responses at several time points after 3 hours.

CONCLUSIONS AND CLINICAL RELEVANCE

Intramuscular L-carvone is analgesic in sheep, although the ethanol-propylene glycol vehicle may cause mild hyperalgesia. This study demonstrates that a food-derived compound can be used to relieve pain in a food-producing animal.

Periplaneta americana (Insecta: Blattodea) and organ fibrosis: A mini review

Fibrosis is the end stage of many chronic inflammatory diseases and eventually leads to organ failure. Periplaneta americana (P. americana) is referred to as "the product of flesh and blood" in traditional Chinese medicine and has a wide range of therapeutic effects. Owing to the growing interest in this insect for its application in the treatment of tissue injury-healing disorders that induce organ fibrosis, it has attracted the interest of researchers. A literature search was performed using core collections of electronic databases, such as PubMed, Web of Science, China National Knowledge Infrastructure, and Wanfang, using the keywords given below and terms such as pharmacological and biochemical details of this insect. P. americana extracts presented a wide range of therapeutic and biological activities, including antifibrotic, antiinflammatory, antioxidative, and tissue repair activities. Emerging evidence suggests that P. americana extracts may improve scarring, pulmonary fibrosis, liver fibrosis, and kidney fibrosis through the regulation of fibroblast activation, cytokine secretion, and deposition of fibrin, indicating the potential role of P. americana as a therapeutic option for organ fibrosis. P. americana is a potential therapeutic agent for treating fibrosis. Further studies are required for a more in-depth characterization of the antifibrogenic mechanism of P. americana prior to its clinical application in the treatment of organ fibrosis. (Fig. 1).