Hesperidin, nobiletin, and tangeretin are collectively responsible for the anti-neuroinflammatory capacity of tangerine peel (Citri reticulatae pericarpium)

• Published in: Food and chemical toxicology Vol. 71; pp. 176 - 182
• Main Authors: Ho, Su-Chen, Kuo, Chun-Ting
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 01.09.2014; Elsevier
• Subjects: active ingredients; Animals; Anti-Inflammatory Agents - pharmacology; Anti-neuroinflammatory activity; Biological and medical sciences; BV2 microglia; Cell Line; Chromatography, High Pressure Liquid; Citrus - chemistry; Flavanone glycoside; flavanones; flavones; Flavones - pharmacology; Food toxicology; functional foods; hesperidin; Hesperidin - pharmacology; interleukin-1beta; interleukin-6; lipopolysaccharides; Medical sciences; Microglia - drug effects; neurodegenerative diseases; neuroglia; nitric oxide; Plant Extracts - pharmacology; Polymethoxy flavone; secretion; Spectrometry, Mass, Electrospray Ionization; Tangerine peel; tangerines; Toxicology; tumor necrosis factor-alpha; Polymethoxy flavone; Flavanone glycoside; BV2 microglia; Tangerine peel; Anti-neuroinflammatory activity; Flavones; Antioxidant; Flavonoid; Microglia; Micronutrient; Polyphenol; Phenols; Peel; Glycoside; Proanthocyanidin; Hesperidin
• ISSN: 0278-6915; 1873-6351; 1873-6351
• DOI: 10.1016/j.fct.2014.06.014

•Flavonoid composition of tangerine peel was analysed by LC–MS.•Anti-neuroinflammatory ability was assessed by an LPS-induced microglial system.•Tangerine peel contains abundant hesperidin, tangeretin and nobiletin.•Dried tangerine peel has potent anti-neuroinflammatory capacity.•Anti-neuroinflammatory ability is attributed to a collective effect of flavonoids. Inhibiting microglial activation-mediated neuroinflammation has become a convincing target for the development of functional foods to treat neurodegenerative diseases. Tangerine peel (Citri reticulatae pericarpium) has potent anti-inflammatory capacity; however, its anti-neuroinflammatory capacity and the corresponding active compounds remain unclear. To this end, the composition of a tangerine peel ethanolic extract was analysed by LC–MS, and the anti-neuroinflammatory ability was evaluated using a lipopolysaccharide (LPS)-activated BV2 microglia culture system. Hesperidin is the most predominant flavonoid in tangerine peel, followed by tangeretin and nobiletin. Among the eight tested flavanone glycosides and polymethoxy flavones, only nobiletin displayed a capacity of>50% to inhibit LPS-induced proinflammatory NO, TNF-α, IL-1β and IL-6 secretion at a concentration of 100μM. At 2mg/ml, tangerine peel extract attenuated LPS-induced NO, TNF-α, IL-1β and IL-6 secretion by 90.6%, 80.2%, 66.7%, and 86.8%, respectively. Hesperidin, nobiletin, and tangeretin individually (at concentrations of 135, 40, and 60μM, respectively) in 2mg/ml tangerine peel extract were only mildly inhibitory, whereas in combination, they significantly inhibited LPS-induced proinflammatory cytokine expression at levels equal to that of 2mg/ml tangerine peel extract. Overall, tangerine peel possesses potent anti-neuroinflammatory capacity, which is attributed to the collective effect of hesperidin, nobiletin, and tangeretin.