Elsevier

Il Farmaco

Volume 56, Issues 5–7, 1 July 2001, Pages 387-389
Il Farmaco

Local anaesthetic activity of β-caryophyllene

https://doi.org/10.1016/S0014-827X(01)01092-8Get rights and content

Abstract

In this work we studied the local anaesthetic activity of β-caryophyllene, one of the main components of clove oil obtained from the dried flower-buds of Syzygium aromaticum (Myrtaceae family). We compared its activity to a chemically related compound, caryophyllene oxide. Anaesthetic activity was evaluated in vivo in the rabbit conjunctival reflex test and in vitro in a rat phrenic nerve-hemidiaphragm preparation. β-Caryophyllene (10−4–1 μg/ml), but not caryophyllene oxide, was able to reduce drastically, in a dose-dependent manner, the electrically evoked contractions of the rat phrenic hemidiaphragm. In the rabbit, conjunctival reflex test treatment with a solution of β-caryophyllene (10–1000 μg/ml) allowed a dose-dependent increase in the number of stimuli necessary to provoke the reflex. As in the in vitro results, caryophyllene oxide was ineffective also in the in vivo test.

In conclusion, these data evidence the local anaesthetic activity of β-caryophyllene, which appears to be strictly dependent on its chemical structure.

Introduction

β-Caryophyllene is a sesquiterpenoid occurring in essential oils, especially in clove oil obtained from the dried flower-buds of Syzygium aromaticum (Myrtaceae family). Clove oil is the best-known herbal product used as a local analgesic and it has long been employed to obtain transient relief from toothache. The local analgesic activity of clove oil is ascribed to its main constituent eugenol which is believed to act on contact to depress the sensory receptors involved in pain perception [1]. Moreover, some findings suggest that eugenol is a local anaesthetic [2]. β-Caryophyllene, the other main component of clove oil, showed anti-inflammatory activity in several animal models, including carrageenan- and PGE-induced hindpaw edema; this activity does not need the integrity of adrenal glands [3]. Furthermore, unlike non-steroidal anti-inflammatory agents, which have gastric side effects, β-caryophyllene seems to have gastric cytoprotective effects in rats [4]. In this work we investigated the local anaesthetic activity of β-caryophyllene and compared its activity to a chemically related compound, caryophyllene oxide.

Section snippets

Animals

Male Wistar rats (150–200 g) and New Zealand albino rabbits (2.5–3.0 kg) from the Morini breeding farm (San Polo d'Enza, Italy) were used. All experiments were carried out according to the guidelines of the European Community Council on animal care.

Rat phrenic nerve-hemidiaphragm preparation

Experiments were performed according to Bülbring [5] and modified by Wessler and Kilbinger [6]. The effect of drugs in the presence of electrical stimulation (0.2 Hz, 0.5 ms, double threshold voltage) was calculated as the percentage variation of

Results and discussion

β-Caryophyllene, in the concentration range of 0.0001–1 μg/ml, was able to reduce, in a dose-dependent manner, the electrically evoked contractions of rat phrenic hemidiaphragm in vitro, up to complete abolishment of contractions (Fig. 1). Under the same experimental conditions the classical local anaesthetic procaine (Fig. 1) exhibited a similar profile to that shown by β-caryophyllene. On the contrary, under the same experimental conditions caryophyllene oxide, up to the dose of 1 μg/ml, did

Acknowledgements

This work was supported by a grant from MURST

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Giornata di Studio SIPHAR (Italian Society for Pharmacognosy), Assisi (Italy), 19 Sept. 2000.

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