Morin hydrate augments phagocytosis mechanism and inhibits LPS induced autophagic signaling in murine macrophage Rekha Jakhar, Souren Paul, Anil Kumar Chauhan, Sun Chul Kang ⁎ Department of Biotechnology, Daegu University, Kyoungsan, Kyoungbook 712-714, Republic of Korea abstract article info Article history: Received 23 May 2014 Received in revised form 1 July 2014 Accepted 16 July 2014 Available online 26 July 2014 Keywords: Immunomodulation Phagocytosis Anticomplement Cytokine Nitric oxide Autophagy Morin, a natural flavonoid that is the primary bioactive constituent of the family Moraceae, has been found to be associated with many therapeutic properties. In this study, we evaluated the immunomodulatory activities of in- creasing concentration of morin hydrate in vitro. Three different concentrations of morin hydrate (5, 10, and 15 μM) were used to evaluate their effect on splenocyte proliferation, phagocytic activity of macrophages, cytokine secretion and complement inhibition. We also evaluated the role of morin hydrate on lipopolysaccharide (LPS) induced autophagy. Our study demonstrated that morin hydrate elicited a significant increase in splenocyte pro- liferation, phagocytic capacity and suppressed the production of cytokines and nitric oxide in activated macro- phages. Humoral immunity measured by anti-complement activity showed an increase in inhibition of the complement system after the addition of morin hydrate, where morin hydrate at 15 μM concentration induced a significant inhibition. Depending on our results, we can also conclude that morin hydrate protects macrophages from LPS induced autophagic cell death. Our findings suggest that morin hydrate represents a structurally diverse class of flavonoid and this structural variability can profoundly affect its cell-type specificity and its biological ac- tivities. Supplementation of immune cells with morin hydrate has an upregulating and immunoprotective effect that shows potential as a countermeasure to the immune dysfunction and suggests an interesting use in inflam- mation related diseases. © 2014 Published by Elsevier B.V. 1. Introduction The immune system is involved in pathophysiologic mechanisms of many diseases so modulation of the immune responses to alleviate var- ious diseases has been of interest for many years [1]. In recent decades, immunomodulatory substances isolated from medicinal plants have also attracted a great deal of attention because of their broad spectrum of therapeutic properties and relatively low toxicity. Medicinal plants have the property to strengthen the immune system, as they are rich source of substances, which are claimed to induce immune- modulation of the cells associated with the immune system [2]. Various studies have been published about the immunomodulatory effect of flavonoids, which show that flavonoids can be responsible for the effects associated with the healing of wounds [3]. Indeed, the basic mechanism of the immunostimulatory effects of flavonoids is thought to occur via macrophage stimulation, inhibition of cytokine secretion, alteration of T-cell differentiation and modulation of the complement system [4]. Flavonoids have major advantages over the use of synthetic immunomodulatory compounds as they are relatively nontoxic and di- etary supplementation with flavonoids may have beneficial effects on human health. Morin hydrate (3,5,7,2,4-pentahydroxyflavone), a yellowish pig- ment that is one of the most common flavonoids, occurs in Morus alba L. (Moraceae). M. alba L. have long been used to improve eyesight, lower blood pressure, prevent diabetes, protect the liver, strengthen joints, treat fever and also reported to have antidiabetic, antioxidative, anti-inflammatory, anti-mutagenesis activities [5–8]. Many other herbs and fruits like Osage orange (Maclura pomifera) [9] are also rich sources of morin which have been extensively studied for their antiox- idant potentials. The intake of antioxidant rich diets has been associated with reduced incidence of chronic diseases such as cancer and cardio- vascular diseases [10]. A diverse array of pathogens has significant impact on the host's ability to respond rapidly and potently by modulating innate immunity, involving many cell types with distinct but overlapping roles [11]. Autophagy and phagocytosis are conserved cellular functions involved in innate immunity. Autophagy offers an immediate autonomous cell defense mechanism by degrading intracellular pathogens and partici- pates in the regulation of immune and inflammatory cell responses [12]. However, autophagy has been reported to have various cellular functions including cell survival as well as cell death. During nutritional International Immunopharmacology 22 (2014) 356–365 ⁎ Corresponding author at: Department of Biotechnology, College of Engineering, Daegu University, Kyoungsan, Kyoungbook 712-714, Republic of Korea. Tel.: +82 53 850 6553; fax: +82 53 850 6559. E-mail address: sckang@daegu.ac.kr (S.C. Kang). http://dx.doi.org/10.1016/j.intimp.2014.07.020 1567-5769/© 2014 Published by Elsevier B.V. Contents lists available at ScienceDirect International Immunopharmacology journal homepage: www.elsevier.com/locate/intimp