Geraniol isolated from lemon grass to mitigate doxorubicin-induced cardiotoxicity through Nrf2 and NF-κB signaling

Geraniol, a natural monoterpene, is a component of many plant essential oils. It contains many medicinal and pharmacological properties. Doxorubicin is an anticancer drug; however, its clinical usage is limited due to its cumulative and dose-dependent cardiotoxicity. This study investigates geraniol as a protective agent against doxorubicin-induced cardiotoxicity and explores possible underlying mechanisms of action.

Male Sprague-Dawley rats were allocated into five groups. Groups 1 and 2 were administered saline and geraniol 200 mg/kg/day/orally, respectively, for 15 days. Group 3 was administered intraperitoneal doxorubicin (5 mg/kg/IP on the 5th, 10th and 15th days to achieve a cumulative dose of 15 mg/kg) to induce cardiotoxicity. The fourth and fifth groups were treated with either geraniol 100 mg/kg or 200 mg/kg orally and doxorubicin to equal the doxorubicin dose administered to Group 3.

Treatment with geraniol significantly ameliorated cardiac damage and restored serum cardiac injury marker levels in doxorubicin treated animals. Geraniol upregulated Nrf2 and HO-1 expression, elevated total antioxidant capacity, decreased the nuclear accumulation of kappa-light-chain enhancer of activated B cells (NF-κB), decreased the phosphorylation and degradation of nuclear factor of kappa light polypeptide gene enhancer in B-cells inhibitor, alpha (IκBα), suppressed tumor necrosis factor-alpha (TNF-α), interleukin 1 beta (IL-1β), and interleukin-18 (IL-18) levels, and restored the levels of Bax and caspase-3 and 9 in heart tissue.

Geraniol may function as a potential activator of nuclear factor erythroid 2-related factor 2 (Nrf2), which subsequently improves Nrf2-dependent antioxidative signaling, diminishes apoptosis and subdues the inflammatory response. The downstream result is protection of the heart from doxorubicin-induced cardiotoxicity.