Flavonoid has potential bioactivity as anticancer agents. The flavonoid of cultivated tobacco (Nicotiana tabacum), locally known as “Kasturi”, leaves was screened for its cytotoxicity against MCF-7 human breast cancer cells and non-transformed Vero cells (African normal cell kidney line) in different concentrations. This study aimed to examine the cytotoxic potential of the flavonoid of Kasturi tobacco leaves against MCF-7 human breast cancer cells. Flavonoid obtained from methanolic extracts of Kasturi tobacco leaves, which have been purified from nicotine. The flavonoid of Kasturi tobacco leaves with concentrations of 20 to 640 μg/mL were exposed to MCF-7 and Vero cells for 24 h. Cell viability was evaluated by 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assay. Flavonoid of Kasturi tobacco leaves with concentrations of 160 μg/mL decreased the MCF-7 cell viability more than 50%, with an inhibitory concentration 50 (IC50) value of 148.41 μg/mL. Meanwhile, it inhibited 50% of Vero cell viability at 255.35 μg/mL. The flavonoid of Kasturi tobacco leaves has cytotoxic activity on MCF-7 cells, and might be a potential alternative agent for human breast cancer therapy.Keywords: flavonoid, tobacco leaves, human breast cancer cells, anticancer activity

Objective: The tobacco leaves are a rich source of many biologically active substances. Flavonoids are one of the bioactive substances contained in tobacco leaves with a wide range of pharmacological properties. This study has been aimed to formulate the antibacterial periodontal gel containing the flavonoids fraction of Kasturi tobacco (Nicotiana tabacum) leaves. Methods: Fraction flavonoids obtained from methanolic extracts of tobacco leaves, which have been purified from nicotine. Different concentrations of flavonoids fraction (0, 25, 0,5, 1, 2, and 4 mg/ml) were prepared with Carbopol-974P. The strength of flavonoid gel adhesion in ex vivo mucosa was tested by the falling liquid film method. Evaluation of in vitro antibacterial agent was followed by the disk diffusion method. Results: The flavonoid gels have better adhesion parameters (time, strength, and distance) than gel bases. The antimicrobial by the zone of inhibition studies proved that flavonoids periodontal gels with concentrations of 4 mg/ml are highly active against Porphyromonas gingivalis with the zone of inhibition >10 mm which was higher than quercetin gel formulations (control groups). Conclusion: Gel formulation containing the flavonoids fraction of Kasturi tobacco (N. tabacum) leaves could be a good candidate for periodontal gel with good mucoadhesive gel and antibacterial agent.