Kajian Hubungan Kuantitatif Struktur-Aktivitas, Penambatan Molekul, Sintesis dan Uji Aktivitas Antikanker Senyawa Iodoxanton

TAUFAN HARI SUGARA, Prof. Drs.Jumina, Ph.D; Prof. Dr. rer. nat. Harno Dwi Pranowo, M.S; Prof. Dr. dr. Eti Nurwening Solikhah,M. Med. Ed. M.Kes

2023 | Disertasi | DOKTOR KIMIA

Pada tahun 2020, terdapat 19,3 juta kasus baru penyakit kanker dengan jumlah kematian sebanyak 10 juta jiwa di dunia. Tingginya kasus kanker diperburuk dengan munculnya kasus resistensi terhadap beberapa obat antikanker seperti 5-fluorourasil, cisplatin, citarabine, and doksorubisin. Senyawa iodoxanton diharapkan dapat menjadi obat antikanker yang bersifat lebih selektif dan sensitif. Penelitian ini bertujuan untuk mengetahui aktivitas antikanker senyawa iodoxanton melalui kajian hubungan kuantitatif struktur-aktivitas, penambatan molekul, sintesis dan uji sitotoksisitasnya secara in vitro. Dalam penelitian ini hubungan kuantitatif struktur-aktivitas (HKSA) digunakan program Hyperchem 8.0.10, Gaussian 09W dan SPSS® (Release 23.0.). Penambatan molekul terhadap protein Epidermal Growth Factor Receptor/EGFR (1M17.pdb) menggunakan program Chimera 1.10, Autodocksuit 4.2.6 dan Discovery studio® 3.1. Sintesis senyawa iodoxanton menggunakan metode Grover, Shah dan Shah dengan mereaksikan turunan iodosalisilat, iodofenol dan pereaksi Eaton. Senyawa hasil sintesis kemudian dikarakterisasi menggunakan spektrometer FT-IR, LC-MS dan NMR. Uji sitotoksisitas menggunakan metode MTT assay terhadap sel kanker hati (HepG2), kanker payudara (MCF-7) dan sel normal (Vero), serta dibandingkan dengan obat standar doksorubisin. Kajian HKSA menunjukkan bahwa metode DFT dengan basis set B3LYP-6311G menjadi metode terbaik untuk optimasi struktur geometri turunan senyawa xanton. Model HKSA yang dihasilkan untuk sel kanker HepG2 yaitu Log IC50 HepG2 = -4,367 - (1,216 x qC7) + (7,293 x qC8a) - (1,907 x qC8) - (22,658 x qO11) - (0,218 x ETA_Eta_R) - (0,182 x ETA_Eta_F_L). Sedangkan untuk sel MCF-7 yaitu Log IC50 MCF-7 = 6,845 - (10,018 x q10a) + (0,940 x qC8) + (20,680 x qC9a) - (2,639 x qC4) - (6,001 x qC1) - (0,022 x Sp) - (0,043 x RDF50u). Senyawa iodoxanton yang memiliki nilai IC50 prediksi kurang dari 25 µg/mL terhadap sel HepG2 maupun MCF-7 yaitu 1,3-dihidroksi, 7-iodoxanton (IX-2), 8-hidroksi, 3-iodoxanton (IX-3), dan 6-hidroksi, 1 iodoxanton (IX-5). Kajian penambatan molekul menunjukkan bahwa ketiga senyawa tersebut membentuk ikatan hidorgen dengan asam amino Met769 yang diketahui sebagai sisi aktif dari protein EGFR. Energi bebas ikatatan yang dihasilkan juga lebih rendah dibandingkan ligan standar erlotinib (AQ4). Sintesis senyawa IX-2, IX-3, dan IX-5 menghasilkan rendemen secara berturut-turut sebanyak 14, 7, dan 9 %. Hasil sintesis berupa padatan berwarna kuning dengan titik leleh 234-243 0C. Ketiga senyawa iodoxanton menunjukkan aktivitas sitotoksik lebih rendah dibandingkan senyawa doksorubisin. Nilai IC50 yang dihasilkan yaitu sebesar 35,34-57,44 µg/mL (sel HepG2) dan 43,37-83,08 µg/mL (sel MCF-7). Meskipun demikian, terdapat kesesuaian antara hasil uji sitotoksisitas dengan hasil kajian HKSA dan penambatan molekul.

In 2020, there were 19.3 million new cancer cases in the world with 10 million death. This high number of cancer cases is worsened by the resistance cases to standard anticancer drugs, such as 5-fluorouracil, cisplatin, cytarabine, and doxorubicin. Iodoxanthone is expected to become a more selective and sensitive anticancer drug. This study aims to explore the anticancer activity of iodoxanthone through QSAR, molecular docking, synthesis, and their cytotoxicity assays. The QSAR study was performed using Hyperchem 8.0.10, Gaussian 09W and SPSS® (Release 23.0.) software. The in silico test was carried out using the molecular docking method against Epidermal Growth Factor Receptor/EGFR protein (1M17.pdb) using Chimera 1.10, Autodocksuit 4.2.6 and Discovery studio® 3.1 software. The iodoxanthone compounds were synthesized using Grover, Shah and Shah method by reacting iodosalicylate, iodophenols and Eaton reagents. The synthesized compounds were characterized using FT-IR, LC-MS and NMR spectrometers. Cytotoxicity test was carried out using the MTT assay method against liver cancer cells (HepG2), breast cancer (MCF-7) and normal cells (Vero), and compared with doxorubicin as the standard drug. Based on the QSAR study, it is known that DFT with basis set B3LYP-6311G was the best method for optimizing the geometric structure of xanthone derivatives. QSAR model for HepG2 cancer cells line is Log IC50 = -4,367 - (1,216 qC7) + (7,293 qC8a) - (1,907 qC8) - (22,658 qO11) - (0,218 ETA_Eta_R) - (0,182 ETA_Eta_F_L). Whereas, QSAR model for MCF-7 cancer cells line is Log IC50 = 6,845 - (10,018 q10a) + (0,940 qC8) + (20,680 qC9a) - (2,639 qC4) - (6,001 qC1) - (0,022 Sp) - (0,043 RDF50u). Based on the QSAR study, iodoxanthone compounds that have good cytotoxic activity (IC50 prediction < 25 µg/mL) against both cancer cell lines are 1,3-dihydroxy-7-iodoxanthone (IX-2), 8-hydroxy-3-iodoxanthone (IX-3) and 6-hydroxy-1-iodoxanthone (IX-5). Molecular docking studies show that these compounds produced lower free binding energy and higher number of hydrogen bonds than erlotinib as the standard ligand. The compounds IX-2, IX-3 and IX-5 were obtained as yellow solid in 14, 7 and 9 % yield, respectively. The melting point of these three compounds was in a range of 234-243 0C. Cytotoxicity test showed that compounds IX-2, IX-3, and IX-5 had lower cytotoxic activity than doxorubicin and predicted QSAR. These compounds gave IC50 values of 35.34-57.44 µg/mL against HepG2 cell line and 43.37-83.08 µg/mL against MCF-7 cell line. However, there is a correspondence between the results of the cytotoxicity test with the QSAR and molecular docking studies.

Kata Kunci : hksa, penambatan molekul, iodoxanton, antikanker, qsar, molecular docking, iodoxanthone, anticancer