[Asam galat adalah salah satu senyawa yang berpotensi menjadi obat baru bagikanker. Banyak penelitian yang telah menguji aktivitas asam galat sebagaiantikanker, tetapi asam galat bersifat sangat hidrofilik sehingga sulit untukmenembus membran sel. Untuk meningkatkan aktivitas sitotoksisitas danhidrofobisitas, dibuat senyawa turunan asam galat yaitu alkil galat dan metoksigalat. Aktivitas diuji pada sel MCF-7 menggunakan MTS (3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium) assaydengan inkubasi selama 48 jam. Aktivitas setiap senyawa ditentukan denganmenggunakan nilai IC50. Dari seluruh senyawa yang diuji, isoamil galat, heptilgalat dan oktil galat, merupakan senyawa yang aktif sebagai antikanker MCF-7dengan nilai IC50 58,11; 25,94 dan 42,34. Berdasarkan ekstrapolasi garis, isobutilgalat dan juga dapat menurunkan persentase viabilitas sel, meskipun nilai IC50-nyabelum dapat ditentukan dari penelitian ini. Metoksi galat tidak memiliki efekpenghambatan pada sel kanker payudara MCF-7. Oleh karena itu, dapatdisimpulkan bahwa isobutil, isoamil, heptil dan oktil galat merupakan senyawaturunan asam galat yang memiliki aktivitas sitotoksik sedangkan metoksi galattidak memiliki aktivitas sitotoksik terhadap MCF-7.;Gallic acid is a potential chemotherapeutic agent. Many studies have proven theanti cancer activity of gallic acid, including in breast cancer. However, gallic acidis a hydrophilic molecule, which restrict the substance from passing the cellmembrane. To increase the potential cytotoxicity and its hydrophobicity, twogroups of gallic acid derivatives, alkyl gallates and methoxy gallates, weredeveloped. The activity of these derivatives were tested in MCF-7 cell lines, usingMTS (3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium) assay, and then incubated for 48 hours. Percentageof cell viability over control were assessed. Cytotoxic activities of gallic acid andits derivatives were determined using IC50 values. Among all of the gallic acidderivatives, isoamyl gallate, heptyl gallate and octyl gallate were the mostpotential drugs to treat MCF-7 breast cancer with IC50 values of 58,11; 25,94 and42,34 μg/ml, respectively. Based on the trendline prediction, isobutyl gallate alsoshowed cytotoxic activity towards MCF-7, although the IC50 values cannot bedetermined in this research. Methoxy gallates do not have any inhibitory activitytowards breast cancer MCF-7. In conclusion, isobutyl, isoamyl, heptyl and octylgallate are gallic acid derivatives with cytotoxic activity, while methoxy gallatesdo not have any cytotoxic activity towards MCF-7., Gallic acid is a potential chemotherapeutic agent. Many studies have proven theanti cancer activity of gallic acid, including in breast cancer. However, gallic acidis a hydrophilic molecule, which restrict the substance from passing the cellmembrane. To increase the potential cytotoxicity and its hydrophobicity, twogroups of gallic acid derivatives, alkyl gallates and methoxy gallates, weredeveloped. The activity of these derivatives were tested in MCF-7 cell lines, usingMTS (3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium) assay, and then incubated for 48 hours. Percentageof cell viability over control were assessed. Cytotoxic activities of gallic acid andits derivatives were determined using IC50 values. Among all of the gallic acidderivatives, isoamyl gallate, heptyl gallate and octyl gallate were the mostpotential drugs to treat MCF-7 breast cancer with IC50 values of 58,11; 25,94 and42,34 μg/ml, respectively. Based on the trendline prediction, isobutyl gallate alsoshowed cytotoxic activity towards MCF-7, although the IC50 values cannot bedetermined in this research. Methoxy gallates do not have any inhibitory activitytowards breast cancer MCF-7. In conclusion, isobutyl, isoamyl, heptyl and octylgallate are gallic acid derivatives with cytotoxic activity, while methoxy gallatesdo not have any cytotoxic activity towards MCF-7.]