Anti-inflammatory effects of polymethoxyflavones from citrus peels: a review

Abstract

Inflammation is a non-specific kind of biological immune response of body tissues to any type of external or internal injuries, such as pathogens, irritants and immune stress reactions. There are two types of inflammation, namely acute and chronic. Acute inflammation starts and develops rapidly, and is aroused by various factors, including injuries, infection, toxins or immune reactions. Chronic inflammation usually lasts for an extended long period of time and results from elimination failure of acute inflammation, autoimmune disorders, various pathogens and pathogenic environments. Except for the damage itself, there exists a direct and intimate connection between chronic inflammation and various clinic common diseases, such as neurodegeneration, as well as metabolic and cardiovascular ailments. Citrus peel is a by-product generated in citrus juice processing. Polymethoxyflavones (PMFs) exist abundantly and almost exclusively in citrus peels, and their biological activities have been broadly investigated in recent years. PMFs have proven to possess potential inhibitory bioactivities towards a number of functional and immune diseases including inflammation. The two most abundant PMFs exhibiting prominent bioactivities in citrus peels are nobiletin and tangeretin, ubiquitously detected in various citrus species. In this review, the beneficial health effects and the underlying molecular mechanisms of ten main citrus PMFs were illustrated against numerous inflammatory diseases, including inflammatory bowel disease (IBD), neuroinflammation and organ inflammation, among others.

Characterization of Citrusnobilis Peel Methanolic Extract for Antioxidant, Antimicrobial, and Anti-Inflammatory Activity

“…The release of lysosomal contents from neutrophils might be inhibited at the inflammation sites for membrane stabilization due to the bioactive compounds present in the extract. The present study is in accordance with the findings of Shin et al [21], Xiong et al [22], He et al [23], and Wang et al [24] who employed these compounds during inflammation treatment.…”

Blockade of STAT3 Signaling Contributes to Anticancer Effect of 5-Acetyloxy-6,7,8,4′-Tetra-Methoxyflavone, a Tangeretin Derivative, on Human Glioblastoma Multiforme Cells

“…We next aimed to elucidate the mechanism of action underlying the anti-GBM effect of 5-AcTMF. It is noteworthy that increasing evidence has underscored persistent activation of STAT3 as a key driver for GBM tumorigenesis, progression, stemness, and resistance to radio- and chemo-therapy [17,18,19,20,21,22,23]. Along this line, we examined the effect of 5-AcTMF on the status of STAT3 activation in GBM cells.…”

“…Polymethoxyflavones (PMFs) are health-promoting flavonoids enriched in the peels of citrus species, such as mandarin and sweet oranges [17,18,19]. Tangeretin (5,6,7,8,4′-pentamethoxyflavone) is the predominant PMF in tangerine peels and is known to exhibit diverse biological activities, including anti-oxidative, anti-inflammatory, and anticancer [20,21,22,23].…”

Zapotin, a Polymethoxyflavone, with Potential Therapeutic Attributes

“…Polymethoxyflavones (PMFs) are natural polyphenols from the group of flavonoids; they are most commonly found in citrus plants such as orange, bergamots, mandarins, grapefruits, limes or tangerine peels, and their biological activities. Which have been shown to be anti-inflammatory, antioxidant, anti-cancer and anti-atherogenic, have been broadly evaluated in recent years [2][3][4]. PMF is a term for a flavone that bears at least two methoxy groups on its basic benzo-γ-pyrone structure.…”