Effects of Nigella sativa supplementation for one month on cardiac reserve in rats.

Nigella sativa (N. sativa) has a long history of use in folk medicine. In a current study performed in this laboratory, two-month dietary supplementation with N. sativa extract to normal rats has shown a homogenous cardiac hypertrophy and enhanced cardiac contractility at baseline conditions. In the present study, shorter (one-month) duration of oral N. sativa administration was adopted to detect possible earlier cardiac responses. In addition, in vitro cardiac stress by the beta adrenoceptor agonist isoproterenol was used to assess the intrinsic cardiac reserve mechanisms. The hearts of Nigella-treated rats developed a moderate but significant hypertrophy that was evident by an increase in the heart weight to body weight ratio. The observed Nigella-induced cardiac hypertrophy was associated with an increase in the baseline cardiac inotropic properties as well as the maximal peak tension generation upon progressive cardiac stress by isoproterenol infusion. The demonstrated selective enhancement of the inotropic reserve favours the physiological nature of Nigella-induced cardiac hypertrophy, similar to that provoked by exercise training.