Introduction:
Myrcene, a terpene found in essential oils sourced from plants, is known to elicit various biological effects such as antioxidant, anti-inflammatory, hypoglycaemic, and hepatoprotective activities. However, reports on the protective effect of myrcene against heart failure are still not clear. Hence, in the present study, the experimental model of heart failure was induced using isoproterenol in rats.

Material and methods:
Wistar male rats were divided into four groups: group I – Control; group II – ISO-induced heart failure; group III – Myrcene pre-treated (1.0 mg/kg/day and ISO); and group IV – Myrcene drug control for the experimental period of 4 weeks. At the end of the treatment, infarct size, cardiac markers, cell stress enzymes such as creatinine kinase, lactate dehydrogenase, inflammatory markers, matrix proteins, and microRNA signatures were elucidated using RT-PCR, ELISA, and immunohistochemistry analysis.

Results:
Rats with induced heart failure demonstrated abnormality in cardiac functions and marker gene expressions, while myrcene pre-treated rats prevented cardiac failure significantly (p < 0.001) with restoration of cellular functions. Also, myrcene pre-treatment abrogated the inflammatory signals with restored matrix proteins. Furthermore, the microRNA of matrix signalling pathways were also found to be prominently reduced compared to heart failure rats.

Conclusions:
Myrcene protected hearts from ISO-induced failure in rats and provided a cardioprotective effect via restoring the matrix signalling, anti-inflammatory, and antioxidant effect, which suggests a possible drug candidature for the treatment of cardiac failure.