QUANTITATIVE ANALYSIS OF SIX MAJOR POLYMETHOXYFLAVONES AND SIX 5-HYDROXYLATED POLYMETHOXYFLAVONES IN CITRUS PEELS

摘要

Polymethoxyflavones (PMFs) and hydroxylated polymethoxyflavones (OH-PMFs) exist exclusively in citrus species, especially rich in the peels of the citrus family. PMFs and OH-PMFs are of particular interest because of their bioactivities, which include antiinflammatory, anti-carcinogenic, and anti-atherogenic properties. For instance, PMFs have been shown to downregulate gene expression of some proinflammatory cytokine such as interleukins (IL-1α, IL-1β, and IL-6) and tumor necrosis factor-α (TNF-α) in mouse macrophages; to inhibit the protein production of inducible nitric oxide synthase (iNOS) also in mouse macrophages; to reduce tumor invasion in animal models; to induce the differentiation of mouse myeloid leukemic cells; to suppress the proliferation of some human cancer cell lines; to have disruptive effect on cell cycle progression while promoting apoptosis; and to reduce the hepatic production of cholesterol containing lipoproteins and to decrease the occurrence of cardiovascular disease. Because of the potentially greater efficacious property relative to their parent polymethoxyflavones (PMFs), OH-PMFs have been attracting greater attention recently. For example, 5-hydroxy-3,6,7,8,3',4'-hexamethoxyfiavone exhibits anti-inflammatory and anti-carcinogenic activity at lower doses relative to its parent compound, 3,5,6,7,8,3',4'-heptamethoxyflavone. 5-Demethylnobiletin also is reported to have more potent activity than its parent compound, nobiletin.