Investigating the role of Cinnamomum verum in zebrafish swim bladder development and anti-cancer activity in human lung cancer cell lines

Abstract

Coughs and allergies are often treated at home with cinnamon (Cinnamomum verum). COVID-19 patients were also benefited by the herb. Aspirating C. verum powder caused pulmonary toxicity, hypercapnia, and respiratory failure in humans and animals. The toxicity of C. verum during fetal lung development is generally unknown. C. verum's effects on lung development were studied in zebrafish. Zebrafish lack lungs but have a swim bladder that functions like mammalian lungs. This study examined C. verum's role in embryonic lung formation using zebrafish swim bladder development. C. verum bark was extracted in methanol, chloroform, ethyl acetate, and hexane. Zebrafish embryos received serial dilutions of these extracts. Methanol extracts of C. verum were not harmful, while hexane, chloroform, and ethyl acetate extracts prevented swim bladder formation and caused neurotoxicity in zebrafish embryos. Organogenesis and lung tumorigenesis share biology. The anti-cancer effect of C. verum against lung cancer is unclear, hence an invitro cell viability study was performed utilizing three human lung cancer cell lines. All extracts decreased lung cancer cell viability, but hexane extract was most effective, inhibiting growth at IC 50 concentrations below 50 µg/ml. The LD50 dose of hexane extract in zebrafish embryonic toxicity exceeds 100 µg/ml, indicating more activity in cancer than normal cells. The extracts also exhibited significant level of ameliorative activity against CuSO4 induced oxidative stress in live zebrafish larvae. Hexane, ethyl acetate, and chloroform fractions have high cinnamaldehyde levels according to GC–MS analyses. Thus, cinnamaldehyde may be the key element in C. verum's lung toxicity and anticancer properties. This study suggested that C. verum crude extract or pure cinnamaldehyde could treat lung cancer. The dose in pregnant women must be carefully monitored to avoid teratogenic effects on fetus lung development.