Authors : Nyotia Nyokat, Charles Rolend Richard, Khong Heng Yen and Korawinwich Boonpisuttinant
Abstract: The development of new drug-resistant is needed than ever as the rapid emergence of new infections and diseases. As such flavones and their derivatives have attracted a tremendous amount of attention due to their significant antibacterial and anti-cancer activities. Hence, this research was aimed to synthesize flavone via. oxidative cyclization of chalcone and determine its antibacterial and anti-cancer activities which its information may help the development of medicine and health research. The synthesis of chalcone was performed by Claisen-Schmidt condensation. Significant reactivity of chalcone was due to conjugated double bonds and completely delocalized π-electron system on both benzene rings. The 2-hydroxy-4, 6- dimethoxyacetophenone was reacted with 4-bromobenzaldehyde in aqueous KOH which act as a catalyst in ethanol to form 3-(4-bromophenyl)-1-(2-hydroxy-4, 6-dimethoxyphenyl)-propan-1-one. It further underwent oxidative cyclization by reaction with iodine (I2) in DMSO as a catalyst to form 2-(4-bromophenyl)-5, 7-dimethoxy-4H-chromen-4-one. Meanwhile, 2-hydroxy-4, 6-dimethoxychalcone (CP1) was synthesized from 2-methoxy-4,6-dimethoxyacetphenone and benzaldehyde. The synthesis of these compounds was characterized using Fourier Transform Infrared Spectroscopy (FTIR), Gas Chromatography-Mass Spectroscopy (GCMS), 13C nuclear magnetic resonance and 1H Nuclear Magnetic Resonance (NMR). The antibacterial activities against Escherichia coli (EC), Pseudomonas aeruginosa (PA), Staphylococcus aureus (SA) and Streptococcus pyogenes (SP) were carried out by a serial dilution method for determination of the Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC). The antibacterial assays indicated 2-hydroxy-4, 6-dimethoxy-4-bromobenzaldehyde is a potent inhibitor against all four types of bacteria with MBC values of 450 μg/mL. However, 2-(4-bromophenyl)-5,7-dimethoxy-4H-chromen-4-one is not a strong inhibitor to all kinds of bacteria in both of antibacterial activities such as MIC and MBC. Besides, CP1 is a potent inhibitor against all four types of bacteria with MBC values of 225 μg/mL. Nevertheless, CP1 demonstrated weak antiproliferation activity against three cancer cell lines namely, breast cancer (MCF-7), cervical cancer (HeLa) and liver cancer (HepG2) which determined using 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) assay.
Nyotia Nyokat, Charles Rolend Richard, Khong Heng Yen and Korawinwich Boonpisuttinant, 2019. Synthesis and Antibacterial Activities of 2-Phenyl-4h-Chromen-One (Flavone). Journal of Engineering and Applied Sciences, 14: 6197-6201.