caryophyllene and Pain

β-caryophyllene (BCP) is a common constitute of the essential oils of numerous spice, food plants and major component in Cannabis. The present study investigated the contribution of peripheral cannabinoid (CB) and opioid systems in the antinociception produced by intraplantar (i.pl.) injection of BCP. The interaction between peripheral BCP and morphine was also examined.. The antinociceptive effect of i.pl. BCP was assayed by the capsaicin tests in mice. Antagonists for CB and opioid receptors, and antisera against β-endorphin were injected peripherally prior to i.pl. injection of BCP. Morphine in combination with BCP was injected subcutaneously or intrathecally.. The i.pl. injection of BCP dose-dependently attenuated capsaicin-induced nociceptive response. The antinociceptive effect produced by BCP was prevented by pretreatment with AM630, a selective CB2 receptor antagonist, but not by AM251, a selective CB1 receptor antagonist. Pretreatment with naloxone, an opioid receptor antagonist, and β-funaltrexamine, a selective μ-opioid receptor antagonist, reversed the antinociceptive effect of BCP. Pretreatment with naloxone methiodide, a peripherally acting antagonist for opioid receptors and antisera against β-endorphin, resulted in a significant antagonizing effect on BCP-induced antinociception. Morphine-induced antinociception was increased by a low dose of BCP. The increased effect of morphine in combination with BCP was antagonized significantly by pretreatment with naloxone.. The present results demonstrate that antinociception produced by i.pl. BCP is mediated by activation of CB2 receptors, which stimulates the local release from keratinocytes of the endogenous opioid β-endorphin. The combined injection of morphine and BCP may be an alternative in treating chemogenic pain.

Topics: Animals; Cannabinoids; Endorphins; Mice; Morphine; Naloxone; Naltrexone; Narcotic Antagonists; Nociception; Pain; Pain Measurement; Polycyclic Sesquiterpenes; Receptor, Cannabinoid, CB2; Sesquiterpenes

Senecio rufinervis D.C (Asteraceae) is a tall aromatic herb, commonly found in Uttarakhand, India. No investigations on the biological activity of this plant have been published so far. Hence, this plant species became a subject of our scientific interest.. The aim of the study was to investigate the chemical composition and analgesic activity of Senecio rufinervis essential oil in mice using both thermal and chemical models of pain.. Essential oil from dried leaves of Senecio rufinervis was extracted by steam distillation and then subjected to GC-MS analysis. Varying doses of essential oil were given to mice, 30 min prior to the induction of abdominal constrictions and determination of mean reaction time in hot-plate maintained at 55° ± 0.5°C.. The main component detected in the essential oil of Senecio rufinervis was germacrene D (40.19%) followed by β-pinene (12.23%), β-caryophyllene (6.21%) and β-longipinene (4.15%). Essential oil exhibited significant and dose-dependent analgesic activity against acetic acid-induced writhing in mice. The percentage inhibition in number of writhes produced by 25, 50 and 75 mg/kg doses was, respectively, 69, 80 and 85%. The oil, at doses 50 and 75 mg/kg, significantly increased the mean latency in the hot-plate after 15 and 30 min of drug administration as compared to the control group.. The results depicted both central and peripheral analgesic activity of S. rufinervis essential oil which was attributed to the presence of terpenes.

Topics: Abdominal Pain; Analgesics; Animals; Bicyclic Monoterpenes; Bridged Bicyclo Compounds; Dose-Response Relationship, Drug; Gas Chromatography-Mass Spectrometry; Hot Temperature; Hyperalgesia; India; Male; Mice; Mice, Inbred Strains; Monoterpenes; Oils, Volatile; Pain; Pain Measurement; Phytotherapy; Plant Leaves; Plant Oils; Polycyclic Sesquiterpenes; Rotarod Performance Test; Senecio; Sesquiterpenes; Sesquiterpenes, Germacrane