Propolis from the North-East region of India exhibits potent antioxidant and anticancer activity against breast cancer cells

Propolis has several uses in human health, including its role as a nutritious and beneficial dietary component, as well as a folk medicine. In this study, we aimed to explore the phytochemical and anticancer activity of propolis collected by honeybees in Assam, India. The chloroform fraction (CF) from the ethanol extract of propolis was screened for antioxidant activity and in vitro cytotoxicity. Finally, the chemical composition of CF was analyzed using gas chromatography-mass spectrometry. CF was found to contain 223.44 ± 5.16 mg/g gallic acid equivalents of total phenolic content and 114.43 ± 7.087 mg quercetin/g of flavonoids. The CF presented antioxidant activities against 2, 2-Diphenyl-1-picrylhydrazyl and 2, 2′-Azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt free radicals, with IC₅₀ values recorded as 68.54 ± 3.1% and 7.26 ± 0.55, respectively. The fractions exhibited growth inhibition in breast cancer cells. The cell migration capacity of both MDA-MB-231 and MCF-7 cells was significantly decreased by CF. Additionally, the fraction was observed to arrest the cell cycle of MDA-MB-231 cells at the S phase and of MCF-7 cells at the G2/M phase. In MDA-MB-231 cells, CF enhanced p53 expression and downregulated CDK2, Cyclin A, Cdc25A, and Cyclin D1, expression whereas in MCF-7 cells, CF downregulated CDK1 and Cyclin B1 expression. Furthermore, confocal microscopy revealed a decrease in the expression of the Ki-67 protein in both MDA-MB-231 and MCF-7 cells following treatment with CF. The propolis from north-east India exhibited antioxidant and anticancer properties in vitro, suggesting its therapeutic potential for breast cancer.