Chemical composition and vascular and intestinal smooth muscle relaxant effects of the essential oil from Psidium guajava fruit

Context: Psidium guajava L. (Myrtaceae) is widely used in traditional medicine for the treatment of various ailments including cardiovascular and gastrointestinal disorders.

Objectives: The current study investigated the chemical composition and cardiovascular and gastrointestinal effects of the essential oil of P. guajava.

Materials and methods: The chemical composition of the essential oil was investigated using gas chromatography-mass spectrometry (GC-MS) technique. The biological activity of the essential oil was tested on rabbit aorta and jejunum. All changes in isometric tension were recorded through a force transducer coupled with a bridge amplifier data acquisition system.

Results and discussion: GC-MS analysis showed the presence of butanoic acid methyl ester, 3-methyl glutaric anhydride, 1-butanol, 3-hexenal, cinnamyl alcohol, 1-hexanol and hexane as the major components. In isolated rabbit aorta preparations, the essential oil showed vasorelaxation at doses of 3-10?mg/mL against high K^+?and phenylephrine pre-contractions with EC₅₀ values of 5.52 (5–6.04) and 6.23?mg/mL (5.0–7.46). The essential oil inhibited spontaneous and high K^+?induced contractions in isolated rabbit jejunum with EC₅₀ values of 0.84 (0.3–1.38) and 0.71?mg/mL (0.3–1.12) and shifted Ca?⁺?² concentration curves to the right, similar to verapamil, suggesting spasmolytic activity mediated possibly through Ca?⁺?² channel blockade.

Conclusions: In summary, the data indicated the presence of seven different phytoconstituents in the essential oil of P. guajava and calcium channel blocking activity, which provides a pharmacological base to the traditional use of P. guajava in cardiovascular and gastrointestinal disorders. Further studies are suggested to explore the molecular nature of these effects.