木犀草素(苷)与药物代谢酶相互作用的研究进展

综述木犀草素及其苷的各相代谢研究及其与药物代谢酶的相互作用。木犀草素的代谢主要受二相代谢酶介导，其苷首先在肠道被水解成苷元，再被吸收，代谢。木犀草素对一相代谢酶CYP3A有诱导作用，而对CYP1A，1B和2E有强抑制作用，此外木犀草素也是CYP2B6，CYP2C9和CYP2D6有效的抑制剂；木犀草素对二相代谢酶SULTs有强抑制作用；并对多种ABC转运蛋白有抑制作用。了解木犀草素及其苷与药物代谢酶的相互作用，对其临床安全合理用药具有重要指导意义。     

木犀草素的药理活性研究

木犀草素是一种天然四羟基黄酮化合物，存在于多种植物中。其具有多种药理活性，如消炎、抗过敏、抗肿瘤、抗菌、抗病毒等，临床主要用于止咳、祛痰、消炎等。本文着重对木犀草素的药理学研究作一综述。     

木犀草素·4,4′-联吡啶药物共晶对小鼠巨噬细胞RAW264.7的抗炎作用研究

目的:研究木犀草素·4,4′-联吡啶药物共晶的抗炎作用及机制。方法:以正常小鼠巨噬细胞RAW264.7为对照,以脂多糖(LPS)诱导的RAW264.7细胞为炎症模型,采用MTT法检测不同浓度(10、20、40、80μmol/L)的木犀草素、4,4′-联吡啶和木犀草素·4,4′-联吡啶药物共晶作用细胞2 h后的细胞活性;荧光定量聚合酶链式反应法测定40μmol/L浓度时细胞中诱导型一氧化氮合酶(i NOS)、环氧合酶2(COX-2)m RNA的表达,酶联免疫吸附法测定40μmol/L浓度时细胞中肿瘤坏死因子α(TNF-α)、白细胞介素6(IL-6)蛋白表达,Western blot法测定40μmol/L浓度时细胞中核转录因子p65(NF-κB p65)蛋白表达。结果:与正常细胞比较,LPS诱导后RAW264.7细胞活性明显降低(P<0.01),i NOS和COX-2 m RNA表达水平及TNF-α、IL-6、NF-κB p65蛋白表达水平均明显升高(P<0.01)。木犀草素和木犀草素·4,4′-联吡啶药物共晶均能增强LPS诱导后RAW264.7细胞活性(P<0.05或P<0.01),且呈浓度依赖性;4,4′-联吡啶对LPS诱导后RAW264.7细胞活性无明显影响;40μmol/L浓度下,木犀草素和木犀草素·4,4′-联吡啶药物共晶可使LPS诱导后细胞中i NOS和COX-2 m RNA表达水平及TNF-α、IL-6、NF-κB p65蛋白表达水平明显降低(P<0.05或P<0.01),其中木犀草素·4,4′-联吡啶药物共晶降低效果强于木犀草素(P<0.05或P<0.01)。结论:木犀草素·4,4′-联吡啶药物共晶可能通过下调NF-κB信号来抑制炎症相关因子产生,其抗炎作用优于木犀草素。     

木犀草素抑制PKM2继而促进自噬诱导肝癌细胞凋亡

目的：探究木犀草素对人肝癌HepG2细胞中PKM2表达的影响，继而挖掘木犀草素诱导肝癌细胞凋亡的机制。方法：通过数据库比较肝癌的癌旁组织和肿瘤组织中的PKM2表达差异，收集肝癌患者标本，检测癌和癌旁组织中PKM2 mRNA和蛋白的表达差异。木犀草素刺激肝癌细胞HepG2，用CCK8、流式凋亡及Western blot方法检测木犀草素对肝癌生存率和凋亡的影响，以及木犀草素作用于肝癌细胞后PKM2的变化。在肝癌细胞系中敲减或过表达PKM2，用木犀草素刺激肝癌细胞，探究PKM2对木犀草素诱导肝癌细胞增殖和凋亡的影响，同时检测自噬相关分子，探究PKM2及木犀草素对自噬的影响。结果：与癌旁组织相比，肿瘤组织中PKM2表达量升高；木犀草素以浓度依赖性和时间依赖性抑制HepG2细胞增殖，诱导细胞凋亡，并且随着木犀草素浓度的增高PKM2的表达逐渐降低；敲减PKM2可以显著抑制肝癌细胞增殖，促进肝癌细胞凋亡，而过表达PKM2可以削弱木犀草素对肝癌细胞的凋亡作用。木犀草素可以促进肝癌细胞自噬，敲减PKM2后可以抑制木犀草素诱导的自噬。结论：木犀草素可以通过抑制PKM2表达，诱导肝癌细胞发生自噬，促进细胞凋亡。     

蜡菊中圣草酚和木犀草素含量测定、抗氧化活性及其反应动力学特性

目的 建立测定蜡菊中圣草酚和木犀草素含量的方法，并对圣草酚和木犀草素的体外抗氧化活性进行评价。方法 采用UPLC进行含量测定方法学研究，以维生素C和Trolox作为对照，通过测定圣草酚和木犀草素清除DPPH自由基的IC₅₀，比较抗氧化活性的强弱；通过4 h内清除自由基速度的变化，初步阐释二者清除DPPH自由基的反应动力学特性。结果 圣草酚和木犀草素分别在0.005 4~0.545 0，0.005 3~0.535 0 mg·mL^–1内，峰面积与浓度线性关系良好（R=0.999 7），方法精密度、稳定性、加样回收率结果满意。4种化合物清除自由基能力由高到低依次为木犀草素>圣草酚>维生素C>Trolox。不同于维生素C和Trolox，圣草酚和木犀草素清除自由基的过程总体呈现先快后慢的3个阶段。结论 含量测定方法较为简便，分析速度快，能用于蜡菊中圣草酚和木犀草素含量测定。圣草酚和木犀草素具有优异的抗氧化活性，蜡菊资源值得进一步开发。     

木犀草素促进囊性纤维化跨膜电导调节因子氯离子通道开放

目的：研究木犀草素对依赖于3，5-环腺苷酸（cAMP）的囊性纤维化跨膜电导调节因子（CFTR）Cl^-通道的激活作用。方法：利用稳定共表达人CFTR与一种对卤族元素敏感的荧光绿蛋白突变体（EYFP-H148Q）的Fischer大鼠甲状腺（FRT）细胞模型，测定木犀草素对CFTR介导的I^-内流速度。结果：木犀草素能够以剂量依赖的方式激活CFTR的I^-转运，其对CFTR Cl^-通道的激活效应具有作用迅速、可逆的特点。木犀草素在发挥激活作用时依赖于腺苷环化酶激动剂Forskolin的存在，其单独与细胞孵育不提高细胞内cAMP的水平。结论：发现了木犀草素能够以剂量依赖方式激活CFTR，并且初步确定了木犀草素通过直接与CFTR结合发挥作用。     

水溶性木犀草素的制备、溶解度测定及α-葡萄糖苷酶抑制作用的研究

目的：设计合成水溶性的木犀草素,并进行分离纯化、结构分析、溶解度测定、α-葡萄糖苷酶抑制及其抑制类型试验.方法：木犀草素与浓硫酸反应生成具有水溶性的磺化产物,并用制备色谱对磺化产物进行分离纯化,采用13C-NMR、MS来确定其结构,HPLC法测定其溶解度,以PNPG为底物考察其对α-葡萄糖苷酶的抑制作用及其抑制类型.结果：合成的水溶性木犀草素中,经分离纯化后获得两种磺化产物,分别为木犀草素-6,6-二硫酸酯二钠和木犀草素-7-硫酸酯钠;两种化合物的溶解度分别是1.235 g/100 g和1.473 g/100 g.在α-葡萄糖苷酶抑制实验中,木犀草素、木犀草素-6,6-二硫酸酯二钠和木犀草素-7-硫酸酯钠抑制α-葡萄糖苷酶的IC50分别是0.003 4,0.003 0,0.002 0 mg·ml-1.结论：改性后的木犀草素磺化产物其溶解度均好,其中木犀草素-7-硫酸酯钠和木犀草素-6,6-二硫酸酯二钠对α-葡萄糖苷酶的抑制作用强于木犀草素.     

鸡肝散提取物在大鼠体内的吸收和分布

采用RP-HPLC法, 分别于SD大鼠灌胃给予鸡肝散提取物后0.17、0.5、1、2、4和6 h, 测定大鼠胃肠道组织中游离以及总的木犀草素的含量, 以及血浆、心、肝、肺、肾中总的木犀草素的含量。结果表明, 鸡肝散提取物中主要成分木犀草素苷在肠道中迅速水解成木犀草素而被吸收, 在胃肠道组织中主要以苷元木犀草素形式存在。木犀草素经吸收后快速分布至各组织, 其中代谢比较旺盛的肝、肾组织中木犀草素的含量高于心、肺组织中; 肾、心、肺组织中的木犀草素含量均为1 h时达最大, 这与血药浓度达峰时间相似; 而在肝组织中, 药物分布迅速, 0.17 h已达高峰; 在其他组织中因检测灵敏度问题而未被检出。建立的大鼠生物样本中木犀草素的含量测定方法具有灵敏、准确、专属性强等特点, 可用于鸡肝散药效成分木犀草素的体内药动学研究。     

木犀草素及其葡萄糖苷的半合成

以橙皮苷为原料，经３步合成了黄酮类化合物木犀草素（１），总收率３５％。本法原料易得，工艺简单，各步收率较好。同时以１通过新化合物木犀草素－７－Ｏ－β－Ｄ－葡萄糖苷四乙酸酯，合成了木犀草素－７－β－葡萄糖苷。     

酸度对木犀草素Cu(Ⅱ)修饰碳糊电极的电化学性质的影响

目的：研究了木犀草素Cu(Ⅱ)修饰碳糊电极在B-R缓冲溶液中的电化学行为。方法：用循环伏安法对木犀草素Cu(Ⅱ)修饰碳糊电极的氧化还原性质进行研究。结果：发现木犀草素Cu(Ⅱ)有一对可逆的氧化还原峰和一个不可逆的还原峰,且峰位随酸度增加向正电位方向移动。结论：木犀草素Cu(Ⅱ)具有良好的电化学活性,同时酸度对电极电位有较大影响。     

A network pharmacology strategy to investigate the anti-inflammatory mechanism of luteolin combined with in vitro transcriptomics and proteomics

Luteolin, a natural flavonoid exists in various medicinal plants, has strong anti-inflammatory effect. However, anti-inflammatory mechanism of luteolin has not been fully explored. Hence, we systematically investigated druggability and anti-inflammatory mechanism of luteolin based on network pharmacology and in vitro experiments. The absorption, distribution, metabolism and excretion of luteolin were evaluated by TCMSP server. Targets associated with luteolin and inflammation were collected from public databases, and the overlapping targets between luteolin and inflammation were analyzed by Draw Venn diagram. Then the protein-protein interaction network of luteolin against inflammation was constructed. Further, gene function and pathway enrichment analysis were performed. Finally, in vitro experiments were carried out to estimate the accuracy of predicted target genes. ADME results indicated that luteolin has great potential to be developed into a drug. 226 overlapping targets were screened by matching 280 targets of luteolin with 9015 targets of inflammation. 9 core targets of luteolin against inflammation were identified, including MMP9, MAPK1, HSP90AA1, CASP3, ALB, EGFR, SRC, HRAS and ESR1. Gene function were mainly involved in metabolism, energy pathways and signal transduction. Metabolic pathways, pathways in cancer, PI3K-AKT signaling pathway, Ras signaling pathway and so on might be the critical pathways of luteolin against inflammation. RT-qPCR and ELISA results indicated that luteolin decreased the expression of most of core genes at protein and mRNA levels (MMP9, MAPK1, HSP90AA1, EGFR, SRC and HRAS). Luteolin is expounded to have great potential to be developed into a drug and target various genes and pathways to perform anti-inflammatory effect.     

Luteolin and chicoric acid synergistically inhibited inflammatory responses via inactivation of PI3K-Akt pathway and impairment of NF-κB translocation in LPS stimulated RAW 264.7 cells

Synergistic anti-inflammatory effects of luteolin and chicoric acid, two abundant constituents of the common dandelion (Taraxacum officinale Weber), were investigated in lipopolysaccharide (LPS) stimulated RAW 264.7 cells. Co-treatment with luteolin and chicoric acid synergistically reduced cellular concentrations of nitric oxide (NO) and prostaglandin E2 (PGE2) and also inhibited expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2). In addition, co-treatment reduced the levels of proinflammatory cytokines, tumor necrosis factor (TNF)-α, and interleukin (IL)-1β. Both luteolin and chicoric acid suppressed oxidative stress, but they did not exhibit any synergistic activity. Luteolin and chicoric acid co-treatment inhibited phosphorylation of NF-κB and Akt, but had no effect on extracellular signal-regulated kinase (ERK), c-Jun NH2-terminal kinase (JNK), and p38. This anti-inflammatory signaling cascade coincides with that affected by luteolin treatment alone. These results suggest that luteolin plays a central role in ameliorating LPS-induced inflammatory cascades via inactivation of the NF-κB and Akt pathways, and that chicoric acid strengthens the anti-inflammatory activity of luteolin through NF-κB attenuation.     

Luteolin, a flavonoid with potential for cancer prevention and therapy

Luteolin, 3',4',5,7-tetrahydroxyflavone, is a common flavonoid that exists in many types of plants including fruits, vegetables, and medicinal herbs. Plants rich in luteolin have been used in Chinese traditional medicine for treating various diseases such as hypertension, inflammatory disorders, and cancer. Having multiple biological effects such as anti-inflammation, anti-allergy and anticancer, luteolin functions as either an antioxidant or a pro-oxidant biochemically. The biological effects of luteolin could be functionally related to each other. For instance, the anti-inflammatory activity may be linked to its anticancer property. Luteolin's anticancer property is associated with the induction of apoptosis, and inhibition of cell proliferation, metastasis and angiogenesis. Furthermore, luteolin sensitizes cancer cells to therapeutic-induced cytotoxicity through suppressing cell survival pathways such as phosphatidylinositol 3'-kinase (PI3K)/Akt, nuclear factor kappa B (NF-kappaB), and X-linked inhibitor of apoptosis protein (XIAP), and stimulating apoptosis pathways including those that induce the tumor suppressor p53. These observations suggest that luteolin could be an anticancer agent for various cancers. Furthermore, recent epidemiological studies have attributed a cancer prevention property to luteolin. In this review, we summarize the progress of recent research on luteolin, with a particular focus on its anticancer role and molecular mechanisms underlying this property of luteolin.     

Mode of peroxisome proliferator-activated receptor γ activation by luteolin

The peroxisome proliferator-activated receptor γ (PPARγ) is a target for treatment of type II diabetes and other conditions. PPARγ full agonists, such as thiazolidinediones (TZDs), are effective insulin sensitizers and anti-inflammatory agents, but their use is limited by adverse side effects. Luteolin is a flavonoid with anti-inflammatory actions that binds PPARγ but, unlike TZDs, does not promote adipocyte differentiation. However, previous reports suggested variously that luteolin is a PPARγ agonist or an antagonist. We show that luteolin exhibits weak partial agonist/antagonist activity in transfections, inhibits several PPARγ target genes in 3T3-L1 cells (LPL, ORL1, and CEBPα) and PPARγ-dependent adipogenesis, but activates GLUT4 to a similar degree as rosiglitazone, implying gene-specific partial agonism. The crystal structure of the PPARγ ligand-binding domain (LBD) reveals that luteolin occupies a buried ligand-binding pocket (LBP) but binds an inactive PPARγ LBD conformer and occupies a space near the β-sheet region far from the activation helix (H12), consistent with partial agonist/antagonist actions. A single myristic acid molecule simultaneously binds the LBP, suggesting that luteolin may cooperate with other ligands to bind PPARγ, and molecular dynamics simulations show that luteolin and myristic acid cooperate to stabilize the Ω-loop among H2', H3, and the β-sheet region. It is noteworthy that luteolin strongly suppresses hypertonicity-induced release of the pro-inflammatory interleukin-8 from human corneal epithelial cells and reverses reductions in transepithelial electrical resistance. This effect is PPARγ-dependent. We propose that activities of luteolin are related to its singular binding mode, that anti-inflammatory activity does not require H12 stabilization, and that our structure can be useful in developing safe selective PPARγ modulators.     

Luteolin Promotes Apoptosis of Endometriotic Cells and Inhibits the Alternative Activation of Endometriosis-Associated Macrophages

Luteolin, a flavonoid present in several fruits, vegetables, nuts, and herbs reportedly exhibits anti-cancer and anti-inflammatory properties. However, the effect of luteolin on endometriosis, a painful condition characterized by the ectopic growth of endometrial tissue and pelvic inflammation, remains elusive. Herein, we observed that luteolin inhibited cell growth and induced apoptosis of 12Z human endometriotic cells by activating caspase-3, -8, and -9. Additionally, luteolin significantly inhibited the expression of key chemokines, C-C motif chemokine ligand 2 (CCL2) and CCL5, required for monocyte/macrophage influx at endometriotic sites. In macrophages stimulated by endometriotic cells, luteolin treatment suppressed the intracellular expression of M2 markers and endometriosis-promoting factors. Collectively, our data suggest that luteolin exerts anti-endometriotic effects by stimulating endometriotic cell apoptosis and hindering the alternative activation of macrophages.     

Luteolin shows an antidepressant-like effect via suppressing endoplasmic reticulum stress

Depression is a significant public health problem and some reports indicate an association between depression and endoplasmic reticulum stress. Luteolin is a flavonoid contained in many plants and with a variety of known pharmacological properties such as anti-inflammatory, anti-anxiety, and memory-improving effects, suggesting that luteolin penetrates into the brain. In the present study, we investigated the effects of luteolin on endoplasmic reticulum stress-induced neuronal cell death. Luteolin significantly suppressed tunicamycin-induced cell death at 1 to 10 μM in human neuroblastoma cells. Luteolin increased in the expression of the 78 kDa glucose-regulated protein and 94 kDa glucose-regulated protein and decreased in the cleavage activation of caspase-3. Additionally, to investigate whether chronic luteolin treatment has an antidepression effect, we performed some behavioral tests. Chronic luteolin treatment showed antidepressant-like effects in behavioral tests and, luteolin attenuated the expression of endoplasmic reticulum stress-related proteins in the hippocampus of corticosterone-treated depression model mice. These findings indicate that luteolin has antidepressant-like effects, partly due to the suppression of endoplasmic reticulum stress.     

Pro-apoptotic effects of the flavonoid luteolin in rat H4IIE cells

Polyphenols are ubiquitous substances in the diet. Their anti-oxidative, anti-inflammatory and anti-viral effects are of interest for human health, and polyphenols such as luteolin are used at high concentrations in food supplements. The aim of this project was to determine the intrinsic effects of luteolin in H4IIE rat hepatoma cells. Luteolin is relatively toxic, cell death was caused via induction of apoptosis as detected by DNA-ladder formation, by nuclear fragmentation and activation of apoptotic enzymes (caspase-2, -3/7, -9 and -8/10). Luteolin (250 microM, 24 h) increased the caspase-3/7 activity four-fold and the caspase-9 activity six-fold. In a time course experiment caspase-9 is activated after 6h, while caspase-2 and -3/7 are activated after 12 h. After 24 h, caspase-8/10 also displays activation. We found a concentration-dependent increase in malondialdehyde release suggesting a prooxidative effect of luteolin. Furthermore, we analysed DNA strand break formation by luteolin and found a distinct increase of DNA strand breaks after incubation for 3h with 100 microM luteolin, a concentration which induces oligonucleosomal DNA cleavage at 24h. In conclusion, the sequence of events is compatible with the assumption that luteolin triggers the mitochondrial pathway of apoptosis, probably by inducing DNA damage.     

Synthesis, characterization, and anti-inflammatory activities of rare earth metal complexes of luteolin

Twelve as yet, unreported complexes of luteolin were synthesized with various rare earth ions through refluxing in ethanol. The characterization of these complexes by elemental analysis, infrared spectra, and differential scanning calorimeter demonstrated that luteolin coordinated the various rare earth ions in a similar manner. Experiments designed to study the anti-inflammatory activities of these rare earth-luteolin complexes indicated that they had a significant inhibitory effect on xylene-induced ear edema in mice. Five complexes containing La³⁺, Ho³⁺, Yb³⁺, Lu³⁺, and Y³⁺ were equally effective as luteolin and dexamethasone (DXM). However, their inhibitory effects on carrageenan-induced paw edema in mice, although significant, were weaker than that of either luteolin alone or DXM.