## 1 Introduction  
Wheat (_Tritcium aestivum_ Linn.) is one of the world's most produced and consumed major food crops and its products are primary diet components, affecting human health directly [1]. It is generally cultivated for its grains used for flour production. Its products exhibit high carbohydrate content, providing energy, and are reach in nutrients, including protein, minerals, vitamins, fibers, and bioactive components [2]. In addition, improved varieties of wheat have been steadily developed with a focus on the high functionality of wheat, such as colored wheat grains having a broad range of colors from red to purple with greater antioxidant activity [3]. An interest in the health benefits of whole grain or wheat bran obtained by milling has been increasing in recent years, and several studies have been reported that whole grain or bran of wheat is helpful in improving health and preventing various diseases such as diabetes, cancer, and allergies [4; 5; 6; 7; 8]. However, there are few reports on the phytochemical and biological study of agro-industrial waste produced after threshing wheat, such as the hull (including spike) and straw. These wheat by-products have been traditionally used as animal feed sources, fuel in the livestock industry, and were studied as wood fiber alternatives [9]. Several studies indicated that wheat parts other than the grain are also rich in pharmacological ingredients [10; 11; 12; 13; 14; 15]. Flavone glycosides and phenolic acids found in its aerial parts showed DPPH free radical scavenging activities [10]. Constituents of its bran or hull were reported to have anticancer activities, for example, oxyphystosterols in its brans induced human colon cancer cell death through the apoptosis pathway [11] and tricin, a major flavone in its hull, was cytotoxic against hepatic and pancreatic cancer cell lines with no effects on normal cell lines [12]. 5-Alk(en)lyresorcinols, aliphatic compounds, and phenolic glycoside found in wheat bran showed anti-allergic activities [8; 13]. Glycolipids and flavonoids isolated from its sprouts inhibited adipogenesis in 3T3-L1 preadipocytes [14; 15]. A summary of the isolates previously reported from various parts of wheat is presented in Table S1 and Figure S1 (Supplementary Materials). Nitric oxide (NO) is a free radical, widely distributed in the body, that regulates various biological functions such as vasodilation, smooth muscle contraction, nerve signal transmission, platelet aggregation inhibition, and immune regulation. It is involved in anticancer, antibacterial, and various inflammatory reactions, and maintains homeostasis [16]. However, if NO is excessively produced, it may cause conditions such as inflammatory reaction hyperactivity and the acceleration of malignant processes [17; 18]. NO synthase (NOS), an enzyme that generates NO using L-arginine as a substrate, could be broadly classified as constitutive NOS (cNOS) and inducible NOS (iNOS). cNOS exhibits an endothelial isoform (eNOS) and a neuronal isoform (nNOS)--eNOS is present in vascular endothelial cells and nNOS is found in the nervous system, pancreatic \(\beta\)-islet cells and bronchi, and gastrointestinal endothelial cells [19; 20]. cNOS expression is controlled by intracellular calcium ion (Ca\({}^{2+}\)) and calmodulin concentrations, whereas iNOS is induced by proinflammatory cytokines, such as lipopolysaccharideaccharide (LPS), interferon-\(\gamma\), interleukin-1, and tumor necrosis factor-\(\alpha\), independently from the cellular Ca\({}^{2+}\) concentration [20; 21; 22]. Therefore, the inhibition of LPS-induced NO production is considered as an iNOS inhibitory process in inflammation and carcinogenesis [23]. In our ongoing research program to find the bioactive compounds from natural sources, a methanol extract as well as \(n\)-hexane, ethyl acetate, and \(n\)-butanol-soluble fractions of _T. aestivum_ hull were tested for NO production inhibitory activity in LPS-activated RAW 264.7 macrophage cells.