Event Abstract Back to Event Synthesis and Nitric Oxide Inhibitory Activities of New Xanthone Derivatives Zi Han Loh1, Siau Hui Mah1*, Soek Sin Teh2 and Gwendoline Cheng Lian Ee3 1 Taylor's University, School of Biosciences, Malaysia 2 Malaysian Palm Oil Board, Engineering and Processing Division, Malaysia 3 Putra Malaysia University, Department of Chemistry, Malaysia Background Xanthones attract great interest from researchers due to their broad pharmacological activities including anti-inflammation depending on the type of substituents and their relative position attached on the xanthone analogue. Increasing demands for effective anti-inflammatory drugs and limitation in obtaining xanthones from natural sources have led to us to synthesize a series of new xanthone derivatives with O-alkylation of 3-hydroxyxanthone to search for possible lead compounds in the treatment of anti-inflammatory diseases. Methods Alkylation was performed where 3-hydroxyxanthone and respective alkyl bromide were reacted with potassium carbonate in acetone with constant stirring under reflux for hours to synthesize xanthone derivatives. These xanthones were characterized by mass spectrometry (MS), nuclear magnetic resonance (NMR) and Fourier transform infrared (FTIR) for structural elucidation. Xanthone derivatives were evaluated for their anti-inflammatory properties by measuring the inhibition effect of nitric oxide (NO) produced by LPS-induced RAW 264.7 cells. Results A series of eleven alkyl substituted xanthone derivatives have been synthesized successfully. All the xanthone derivatives exhibited NO inhibition effects with the IC50 values in the range of 2.82 ± 0.20 to 24.27 ± 1.65 µg/mL, which are lower than the standard drug, diclofenac sodium with an IC50 value of 59.49 ± 1.09 µg/mL. The results indicated that these compounds possessed significant NO inhibition activities. Structure-activity relationship (SAR) study revealed that the xanthones with branched alkyl substituents showed stronger activities than the linear alkyl substituted xanthones. Among the derivatives, 3-(cyclobutylmethoxy)-9H-xanthen-9-one is the most potent NO inhibitor with an IC50 value of 2.82 ± 0.20 µg/mL. Conclusion Different alkylated substituted xanthone derivatives have been successfully synthesized and showed significant NO inhibitory activity. The result suggested that C3 substituted cyclobutylmethoxy xanthone is a promising NO inhibitor. Thus, further studies on the molecular mechanism of this xanthone is proposed in due course. Acknowledgements The authors acknowledge the Fundamental Research Grant Scheme (FRGS) (FRGS/1/2015/SG01/TAYLOR/03/1) from the Ministry of Higher Education (MOHE) for financial support. Keywords: 3-hydroxyxanthone, Structure activity relationship (SAR), Alkyl substituents, anti-inflammation, Alkylation Conference: International Conference on Drug Discovery and Translational Medicine 2018 (ICDDTM '18) “Seizing Opportunities and Addressing Challenges of Precision Medicine”, Putrajaya, Malaysia, 3 Dec - 5 Feb, 2019. Presentation Type: Oral Presentation Topic: Miscellaneous Citation: Loh Z, Mah S, Teh S and Ee G (2019). Synthesis and Nitric Oxide Inhibitory Activities of New Xanthone Derivatives. Front. Pharmacol. Conference Abstract: International Conference on Drug Discovery and Translational Medicine 2018 (ICDDTM '18) “Seizing Opportunities and Addressing Challenges of Precision Medicine”. doi: 10.3389/conf.fphar.2018.63.00042 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 30 Sep 2018; Published Online: 17 Jan 2019. * Correspondence: Dr. Siau Hui Mah, Taylor's University, School of Biosciences, Subang Jaya, Malaysia, siauhui.mah@taylors.edu.my Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Zi Han Loh Siau Hui Mah Soek Sin Teh Gwendoline Cheng Lian Ee Google Zi Han Loh Siau Hui Mah Soek Sin Teh Gwendoline Cheng Lian Ee Google Scholar Zi Han Loh Siau Hui Mah Soek Sin Teh Gwendoline Cheng Lian Ee PubMed Zi Han Loh Siau Hui Mah Soek Sin Teh Gwendoline Cheng Lian Ee Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.