Citation: Wikan, N.; Potikanond, S.; Hankittichai,P.; Thaklaewphan, P.; Monkaew, S.; Smith, D.R.; Nimlamool, W. Alpinetin Suppresses Zika Virus-Induced Interleukin-1β Production and Secretion in Human Macrophages. Pharmaceutics 2022, 14, 2800. https://doi.org/10.3390/ pharmaceutics14122800 Academic Editor: Ariane Leite Rozza Received: 3 November 2022 Accepted: 11 December 2022 Published: 14 December 2022 Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affil- iations. Copyright: © 2022 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/). pharmaceutics Article Alpinetin Suppresses Zika Virus-Induced Interleukin-1β Production and Secretion in Human Macrophages Nitwara Wikan 1,2 , Saranyapin Potikanond 1,3 , Phateep Hankittichai 1 , Phatarawat Thaklaewphan 1 , Sathit Monkaew 1 , Duncan R. Smith 2, * and Wutigri Nimlamool 1,3, * 1 Department of Pharmacology, Faculty of Medicine, Chiang Mai University, Chiang Mai 50200, Thailand 2 Institute of Molecular Biosciences, Mahidol University, Salaya, Nakhon Pathom 73170, Thailand 3 Research Center for Development of Local Lanna Rice and Rice Products, Chiang Mai University, Chiang Mai 50200, Thailand * Correspondence: duncan_r_smith@hotmail.com (D.R.S.); wutigri.nimlamool@cmu.ac.th (W.N.); Tel.: +66-53-934597 (W.N.) Abstract: Zika virus (ZIKV) infection has been recognized to cause adverse sequelae in the developing fetus. Specially, this virus activates the excessive release of IL-1β causing inflammation and altered physiological functions in multiple organs. Although many attempts have been invested to develop vaccine, antiviral, and antibody therapies, development of agents focusing on limiting ZIKV-induced IL-1β release have not gained much attention. We aimed to study the effects of alpinetin (AP) on IL-1β production in human macrophage upon exposure to ZIKV. Our study demonstrated that ZIKV stimulated IL-1β release in the culture supernatant of ZIKV-infected cells, and AP could effectively reduce the level of this cytokine. AP exhibited no virucidal activities against ZIKV nor caused alteration in viral production. Instead, AP greatly inhibited intracellular IL-1β synthesis. Surprisingly, this compound did not inhibit ZIKV-induced activation of NF-κB and its nuclear translocation. However, AP could significantly inhibit ZIKV-induced p38 MAPK activation without affecting the phosphorylation status of ERK1/2 and JNK. These observations suggest the possibility that AP may reduce IL-1β production, in part, through suppressing p38 MAPK signaling. Our current study sheds light on the possibility of using AP as an alternative agent for treating complications caused by ZIKV infection-induced IL-1β secretion. Keywords: Zika virus; alpinetin; inflammation; IL-1β; p38 MAPK 1. Introduction Zika virus infection can be asymptomatic or may cause mild symptoms [1]. Never- theless, it may cause severe diseases including congenital brain abnormalities [2,3] and Guillain–Barré syndrome [2,4,5]. In addition, lack of symptoms in ZIKV-infected cases may also lead to potential complications. For instance, it has been reported that the incidence of ZIKV-associated birth abnormalities (primarily brain abnormalities and microcephaly) of fetuses or infants born to asymptomatic or symptomatic women with ZIKV infection was not different [6]. Besides targeting important cells residing in the brain such as neural progenitor cells, astrocytes, and functional neurons, ZIKV can also infect cells in many organs [7]. Specifically, it has been demonstrated that ZIKV infected eyes, vagina, placenta, uterus, and testis [8,9]. ZIKV could also target renal proximal tubular epithelia and glomeru- lar parenchymal cells [10,11]. Moreover, ZIKV infected monocytes and macrophages and utilized these cells as its replication reservoir [12,13]. In response to ZIKV infection, interleukin-1β (IL-1β) was highly increased, suggesting that it may be the cause of the ZIKV-associated diseases [14]. Usually, IL-1β secretion mediates the host defense system against pathogens. For example, IL-1β was proved to regulate the generation of cholesterol to 25-hydroxycholesterol by the enzyme cholesterol 25-hydroxylase (CH25H), and that exhibited broad antiviral properties [15]. Nevertheless, Pharmaceutics 2022, 14, 2800. https://doi.org/10.3390/pharmaceutics14122800 https://www.mdpi.com/journal/pharmaceutics