Bisabolol mitigates isoproterenol-induced myocardial infarction in rats

Introduction: Myocardial infarction is becoming a leading cause of morbidity and mortality worldwide. Preventative and/or therapeutic interventions using natural products for ischaemic heart disease, i.e. myocardial infarction, have gained considerable attention worldwide. Objectives: This study investigated the cardioprotective effect and possible mechanism of bisabolol (BSB), a natural monocyclic sesquiterpene alcohol, which has garnered attention in recent years because of its antioxidant and anti-inflammatory activities. Materials and methods: This study used a clinically relevant animal model; the isoproterenol (ISO)-induced myocardial infarction model in rats. ISO, is a non-selective β -adrenergic agonist, which mimics human myocardial infarction involving subendocardial ischaemia, haemodynamic dysfunction and contractile impairment. Rats were pretreated for 14 days with BSB (20mg/kg/day, per oral) before inducing myocardial injury by subcutaneous injection of isoproterenol (85mg/kg body weight) for two consecutive days at an interval of 24hours. Results: Rats given isoproterenol showed elevated serum levels of malondialdehyde, cardiac markers (creatine kinase-MB isoenzyme, lactate dehydrogenase, serum glutamic oxaloacetic transaminase and serum glutamate-pyruvate transaminase), markers of inflammation (interleukin-1β , interleukin-6 and tumour necrosis factor alpha), oxidative stress (decreases in the level of the reduced form of glutathione and activities of superoxide dismutase and catalase) and nitric oxide, when compared with normal control. Pretreatment with BSB significantly reduced the elevation of these oxidative/nitrosative stress and inflammatory markers. BSB treatment strengthened antioxidant status and attenuated ISO-induced myocardial lipid peroxidation. Preservation of histoarchitecture of the heart further supported the biochemical findings and demonstrated the cardioprotective effect of BSB. The cardioprotective effect of the BSB treatment could be due to its antilipid peroxidative, antioxidant and anti-inflammatory properties. Conclusions: Result suggested that BSB may have a potential benefit in preventing ischaemic heart disease, such as myocardial infarction. Considering the safety profile of BSB and its additional activities, BSB has tremendous therapeutic potential in a multitude of other diseases associated with inflammation and oxidative stress. Acknowledgements: College of Medicine and Health Sciences for a research grant and Dr Shreesh Ojha for supervising this project.