Nanovesicle-formulated Sterculia coccinea Jack (hantap) leaf extract: Estrogen receptor-alpha molecular docking and cytotoxicity in Michigan Cancer Foundation-7 cells

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BSTRACT

Sterculia coccinea Jack (hantap) is an Indonesian medicinal plant with limited evidence of anticancer activity. The objective of this study was to identify the phytochemical components of hantap leaf extract, evaluate its interaction with estrogen receptor-alpha (ER-α) through molecular docking, and develop nanoliposome formulations to improve its physicochemical properties. The extract yield was 15.7%, and the phytochemical profile was characterized using liquid chromatography–high-resolution mass spectrometry. Molecular docking against ER-α was performed using tamoxifen as the reference ligand. Nanoliposomes were prepared by thin-film hydration using phosphatidylcholine and cholesterol at ratios of 0.6:0.3 (F1), 0.9:0.3 (F2), and 1.2:0.3 (F3). The formulations showed particle sizes of 158.3 ± 1.59 nm, 148.23 ± 2.68 nm, and 157.3 ± 1.10 nm; zeta potentials of − 30.16 ± 1.40 mV, −31.61 ± 0.16 mV, and − 32.84 ± 0.31 mV; and polydispersity index values of 0.28 ± 0.02, 0.29 ± 0.03, and 0.23 ± 0.02 for F1, F2, and F3, respectively. Entrapment efficiency for total phenolics ranged from 94.43% to 97.04%, while total flavonoid entrapment ranged from 32.84% to 73.54%. Docking analysis showed that linarin and apigenin had stronger binding affinity to ER-α than tamoxifen. Based on physicochemical evaluation, F2 was selected as the optimal formulation and showed weak cytotoxic activity against Michigan Cancer Foundation-7 (MCF-7) cells in the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide assay, with an IC ₅₀ value of 282.06 ± 3.39 μg/mL. In conclusion, hantap leaf extract nanoliposomes exhibited favorable nanoscale characteristics, while their cytotoxic effect against MCF-7 cells remained weak under the tested conditions.