Screening of bioactive ingredients of Tsantan Sumtang in ameliorating H9c2 cells injury.

ETHNOPHARMACOLOGICAL RELEVANCE: Tsantan Sumtang (TS), a traditional Tibetan medicine, has been used in the clinic for the treatment of myocardial ischemia (MI) for ages, however, the bioactive ingredients that are responsible for improving MI remain unknown. AIM OF THE STUDY: This study investigated the chemical components of TS and their medicinal efficacies at cell levels, in order to expound the bioactive ingredients in TS. MATERIALS AND METHODS: First, a response-surface methodology was employed to determine the optimum ethanol reflux extraction process of polyphenols in TS (PTS) due to their close correlation with MI improvement. Second, a serum pharmacochemistry technique was used to analyze the compounds of PTS absorbed into the blood of rats. Third, hypoxia-, H2O2-, and adriamycin (ADM)-induced H9c2 cell injury models were used to investigate the cardioprotective effects of these compounds in vitro. Fourth, protective effects of isovitexin, quercitrin, and isoeugenol on mitochondrial function were further tested. RESULTS: The optimum extraction conditions for obtaining PTS were an ethanol concentration of 78.22%, an extraction time of 67.4 min, and a material-liquid ratio of 1:72.60 mL/g. Serum pharmacochemistry analysis detected 21 compounds, of which 11 compounds were always present in the blood within 5 h. Cytotoxicity and the protective effect of 11 compounds in hypoxia-, H2O2-, and ADM-induced H9c2 cell injury models shown that isovitexin, quercitrin, and isoeugenol had almost no cytotoxicity, and they could elevate the survival rate in injured H9c2 cells. Furthermore, isovitexin, quercitrin, and isoeugenol could decrease mitochondrial reactive oxygen species (ROS) releasion, inhibite mitochondrial permeability transition pore (mPTP) opening, ameliorate the change of mitochondrial membrane potential (MMP) to exert mitochondrial protection effect. CONCLUSION: Isovitexin, quercitrin, and isoeugenol exhibited cardioprotective effect at cell levles, these three compounds might be the bioactive ingredients in TS. These findings elucidate the pharmacodynamic substances and mechanisms of TS, guiding its clinical use.

Protective mechanism of Erigeron breviscapus injection on blood-brain barrier injury induced by cerebral ischemia in rats.

This study investigates the protective effect of Erigeron breviscapus injection, a classic traditional Chinese medicine most typically used by Chinese minority to treat stroke, on cerebral ischemia-reperfusion injury and the related signaling pathways. Use network pharmacology methods to study the relationship between E. breviscapus (Vant.) Hand-Mazz. and ischemic stroke, predict the mechanism and active ingredients of E. breviscapus (Vant.) Hand-Mazz. in improving ischemic stroke disease. We study the protective effect of E. breviscapus injection on blood-brain barrier (BBB) injuries induced by cerebral ischemia in rats by regulating the ROS/RNS-MMPs-TJs signaling pathway. The rat model of focal cerebral ischemia-reperfusion injury has been prepared using the wire-suppository method. Firstly, the efficacy of E. breviscapus injection, Scutellarin and 3,5-dicaffeoylquinic acid in protecting BBB injury caused by cerebral ischemia has been evaluated. Secondly, the following two methods have been used to study the mechanism of E. breviscapus injection in regulating the ROS/RNS-MMPS-TJS signaling pathway: real-time PCR and western blot for the determination of iNOS, MMP-9, claudin-5, occludin, ZO-1 mRNA and protein expression in brain tissue. We find that PI3K-Akt signaling pathway predicted by network pharmaology affects the blood-brain barrier function, so we chose the blood-brain barrier-related MMP-9, claudin-5, iNOS, occludin and ZO-1 proteins are used for research. The results of our research show that 3 drugs can reduce the rate of cerebral infarction in rats, relieve the abnormal neuroethology of rats, reduce the degree of brain tissue lesion, increase the number of the Nissl corpuscle cells and repair the neuron ultrastructure in injured rats. At the same time, it can obviously reduce the ultrastructure damage of the BBB in rats. All three drugs significantly reduced the content of Evans blue in the ischemic brain tissue caused by cerebral ischemia in rats with BBB injury. In addition, E. breviscapus injection, Scutellarin and 3,5-dicaffeoylquinic acid can decrease the protein expression of iNOS and MMP-9 in rat ischemic brain tissue. In addition, 3,5-dicaffeoylquinic acid can increase the protein expression of claudin-5. We conclude that E. breviscapus injection, Scutellarin and 3,5-dicaffeoylquinic acid have obvious therapeutic effects on BBB and neuron injury induced by cerebral ischemia in rats. Our results from studying the mechanism of action show that E. breviscapus injection and Scutellarin inhibited the activation of MMP-9 by inhibiting the synthesis of iNOS, 3,5-dicaffeoylquinic acid inhibits the expression and activation of MMP-9 by inhibiting the activation of iNOS and reducing the generation of free radicals, thus reducing the degradation of important cytoskeleton connexin claudin-5 in the tight junction (TJ) structure by inhibiting the expression and activation of MMP-9. Finally BBB structure integrity was protected.

Apigenin ameliorates hyperuricemic nephropathy by inhibiting URAT1 and GLUT9 and relieving renal fibrosis via the Wnt/ß-catenin pathway.

BACKGROUND: Hyperuricemia (HUA) is characterized by abnormal serum uric acid (UA) levels and demonstrated to be involved in renal injury leading to hyperuricemic nephropathy (HN). Apigenin (API), a flavonoid naturally present in tea, berries, fruits, and vegetables, exhibits various biological functions, such as antioxidant and anti-inflammatory activity. PURPOSE: To investigate the effect of API treatment in HN and to reveal its underlying mechanisms. METHODS: The mice with HN were induced by potassium oxonate intraperitoneally and orally administered for two weeks. The effects of API on renal function, inflammation, fibrosis, and uric acid (UA) metabolism in mice with HN were evaluated. The effects of API on urate transporters were further examined in vitro. RESULTS: The mice with HN exhibited abnormal renal urate excretion and renal dysfunction accompanied by increased renal inflammation and fibrosis. In contrast, API reduced the levels of serum UA, serum creatinine (CRE), blood urea nitrogen (BUN) and renal inflammatory factors in mice with HN. Besides, API ameliorated the renal fibrosis via Wnt/ß-catenin pathway suppression. Furthermore, API potently promoted urinary UA excretion and inhibited renal urate transporter 1 (URAT1) and glucose transporter 9 (GLUT9) in mice with HN. In vitro, API competitively inhibited URAT1 and GLUT9 in a dose-dependent manner, with IC50 values of 0.64 ± 0.14 µM and 2.63 ± 0.69 µM, respectively. CONCLUSIONS: API could effectively attenuate HN through co-inhibiting UA reabsorption and Wnt/ß-catenin pathway, and thus it might be a potential therapy to HN.

Cytotoxicity of apigenin toward multiple myeloma cell lines and suppression of iNOS and COX-2 expression in STAT1-transfected HEK293 cells.

BACKGROUND: Apigenin is one of the most abundant dietary flavonoids that possesses multiple bio-functions. PURPOSE: This study was designed to determine the influence of apigenin on gene expressions, cancer cells, as well as STAT1/COX-2/iNOS pathway mediated inflammation and tumorigenesis in HEK293-STAT1 cells. Furthermore, the cytotoxic activity toward multiple myeloma (MM) cell lines was investigated. METHODS: Bioinformatic analyses were used to predict the sensitivity and resistance of tumor cells toward apigenin and to determine cellular pathways influenced by this compound. The cytotoxic and ferroptotic activity of apigenin was examined by the resazurin reduction assay. Additionally, we evaluated apoptosis, and cell cycle distribution, induction of reactive oxygen species (ROS) and loss of integrity of mitochondrial membrane (MMP) by using the flow cytometry analysis. DAPI staining was used to detect characteristic apoptotic features. Furthermore, we verified its anti-inflammatory and additional mechanism of cell death by western blotting. RESULTS: COMPARE and hierarchical cluster analyses exhibited that 29 of 55 tumor cell lines were sensitive against apigenin (p < 0.001). The Ingenuity Pathway Analysis data showed that important bio-functions affected by apigenin were: gene expression, cancer, hematological system development and function, inflammatory response, and cell cycle. The STAT1 transcription factor was chosen as target protein on the basis of gene promoter binding motif analyses. Apigenin blocked cell proliferation of wild-type HEK293 and STAT1 reporter cells (HEK293-STAT1), promoted STAT1 suppression and subsequent COX-2 and iNOS inhibition. Apigenin also exhibited synergistic activity in combination with doxorubicin toward HEK293-STAT1 cells. Apigenin exerted excellent growth-inhibitory activity against MM cells in a concentration-dependent manner with the greatest activity toward NCI-H929 (IC50 value: 10.73 ± 3.21 µM). Apigenin induced apoptosis, cell cycle arrest, ferroptosis and autophagy in NCI-H929 cells. CONCLUSION: Apigenin may be a suitable candidate for MM treatment. The inhibition of the STAT1/COX-2/iNOS signaling pathway by apigenin is an important mechanism not only in the suppression of inflammation but also in induction of apoptosis.

An ultra high performance liquid chromatography with tandem mass spectrometry method for simultaneous determination of thirteen components extracted from Radix Puerariae in rat plasma and tissues: Application to pharmacokinetic and tissue distribution study.

A rapid and sensitive ultra high performance liquid chromatography with tandem mass spectrometry method was established and validated for simultaneous determination of thirteen bioactive components (gallic acid, protocatechuic acid, puerarin, p-hydroxycinnamic acid, daidzin, ononin, daidzein, naringenin, genistein, apigenin, formononetin, biochanin A, and ß-sitosterol) of Radix Puerariae extract in rat plasma and tissues. The plasma and tissues samples were pretreated by protein precipitation extraction, and umbelliferone and rutin were used as internal standards. Sample separation was performed on a ZORBAX RRHD Eclipse plus C18 column (2.1 mm × 50 mm, 1.8 µm, Agilent) with a mobile phase consisting of methanol-water (containing 0.1% formic acid). The mass spectrometry analysis was conducted in positive and negative ionization modes with multiple reaction monitoring. The lower limit of quantitation range for the 13 analytes was 0.2-35 ng/mL. The intra- and inter-day precision of all the analytes were less than 10.92%, with an accuracy ranging from -13.10 to 11.96%. Both the recovery and matrix effect were within acceptable limits. This method was successfully applied to pharmacokinetic and tissue distribution study of the 13 bioactive components in rats after oral administration of R. Puerariae extract.

Vitexin ameliorates preeclampsia phenotypes by inhibiting TFPI-2 and HIF-1α/VEGF in a l-NAME induced rat model.

Preeclampsia (PE) is a leading cause of maternal and perinatal morbidity and mortality with few safe, effective, and minimally invasive therapeutics. Inflammation, oxidative stress, and angiogenic imbalance have been reported to contribute to PE pathogenesis. Vitexin (VI) possesses various pharmacological activities including the potent regulation of the above biological processes in different conditions. This study aims to investigate whether VI has therapeutic potential to PE and the underlying mechanisms. Sprague-Dawley pregnant rats pretreated with or without VI were fed with l-NAME-containing water to induce experimental PE. Results showed that VI decreased high systolic blood pressure and urinary protein in PE rats time- and dose-dependently. Meanwhile, VI of higher dosage (45, 60 mg/kg) corrected abnormal pregnancy outcomes, including low pup weight and low pups/placenta ratio. In addition, VI of high dosage (60 mg/kg) decreased sFlt-1, increased PlGF and alleviated oxidative stress both in blood and placental samples compared with nontreated PE group. Furthermore, VI alleviated placental TFPI-2, HIF 1α, and VEGF in PE rats. In short, the present study suggests that the inhibition of placental TFPI-2 and HIF-1α/VEGF might be one of the potential mechanisms underlying the protective effects of VI to experimental PE induced by l-NAME.

Protective Effects of Ligustroflavone, an Active Compound from Ligustrum lucidum, on Diabetes-Induced Osteoporosis in Mice: A Potential Candidate as Calcium-Sensing Receptor Antagonist.

Ligustroflavone is one major compound contained in active fraction from Fructus Ligustri Lucidi (the fruit of Ligustrum lucidum), which could regulate parathyroid hormone (PTH) levels and improve calcium balance by acting on calcium-sensing receptors (CaSR). This study aimed to explore the potency of ligustroflavone as a CaSR antagonist and its protective effects against diabetic osteoporosis in mice. LF interacted well with the allosteric site of CaSR shown by molecular docking analysis, increased PTH release of primary parathyroid gland cells and suppressed extracellular calcium influx in HEK-293 cells. The serum level of PTH attained peak value at 2 h and maintained high during the period of 1 h and 3 h than that before treatment in mice after a single dose of LF. Treatment of diabetic mice with LF inhibited the decrease in calcium level of serum and bone and the enhancement in urinary calcium excretion as well as elevated circulating PTH levels. Trabecular bone mineral density and micro-architecture were markedly improved in diabetic mice upon to LF treatment for 8 weeks. LF reduced CaSR mRNA and protein expression in the kidneys of diabetic mice. Taken together, ligustroflavone could transiently increase PTH level and regulate calcium metabolism as well as prevent osteoporosis in diabetic mice, suggesting that ligustroflavone might be an effective antagonist on CaSR.

Improvement of diabetic wound healing by topical application of Vicenin-2 hydrocolloid film on Sprague Dawley rats.

BACKGROUND: Impaired wound healing is a debilitating complication of diabetes that leads to significant morbidity, particularly foot ulcers. The risk of developing diabetic foot ulcers for diabetic patients is 15% over their lifetime and approximately 85% of limb amputations is caused by non-healing ulcers. Unhealed, gangrenous wounds destroy the structural integrity of the skin, which acts as a protective barrier that prevents the invasion of external noxious agents into the body. Vicenin-2 (VCN-2) has been reported to contain prospective anti-oxidant and anti-inflammatory properties that enhance cell proliferation and migration. Sodium Alginate (SA) is a natural polysaccharide that possesses gel forming properties and has biodegradable and biocompatible characteristics. Therefore, the objective of this study is to evaluate the effect of SA wound dressings containing VCN-2 on diabetic wounds. METHODS: Wounds were inflicted in type-1 diabetic-streptozotocin (STZ) induced male Sprague Dawley rats. Subsequently, relevant groups were topically treated with the indicated concentrations (12.5, 25 and 50 µM) of VCN-2 hydrocolloid film over the study duration (14 days). The control group was treated with vehicle dressing (blank or allantoin). Wounded tissues and blood serum were collected on 0, 7 and 14 days prior to sacrifice. Appropriate wound assessments such as histological tests, nitric oxide assays, enzyme-linked immunosorbent assays (ELISA) and immunoblotting assays were conducted to confirm wound healing efficacy in the in vivo model. One-way Analysis of Variance (ANOVA) was used for statistical analysis. RESULTS: Results showed that hydrocolloid film was recapitulated with VCN-2 enhanced diabetic wound healing in a dose-dependent manner. VCN-2 reduced pro-inflammatory cytokines (IL-1ß, IL-6 and TNF-α), mediators (iNOS and COX-2), and nitric oxide (NO) via the NF-κB pathway. Data suggests that the VCN-2 film facilitated healing in hyperglycemic conditions by releasing growth factors such as (VEGF and TGF-ß) to enhance cell proliferation, migration, and wound contraction via the VEGF and TGF-ß mechanism pathways. CONCLUSIONS: This study's findings suggest that VCN-2 may possess wound healing potential since topical treatment with VCN-2 hydrocolloid films effectively enhanced wound healing in hyperglycemic conditions.

Scutellarein selectively targets multiple myeloma cells by increasing mitochondrial superoxide production and activating intrinsic apoptosis pathway.

OBJECTIVES: Scutellarein is a flavonoid monomer found in traditional Chinese medicine such as Scutellaria barbata. This study aimed to investigate the cytotoxic effect of scutellarein treatment on multiple myeloma (MM) cells. METHODS: circulating B lymphocytes (CBL) isolated from healthy donors' peripheral blood served as control for MM.1R and IM-9 MM cells. CLB and MM cells were treated with various concentrations of scutellarein before their cell viability and apoptosis being evaluated. Nude mice burdened with MM xenograft tumor were intravenously injected with different concentrations of scutellarein, and their tumor burden change were monitored. Apoptosis of MM cells or CBL after scutellarein treatment was assayed by measuring caspase-3, -8 and -9 activities. FADD or APAF1 gene knockdown in MM cells was achieved by lentiviral transfection. Amount of Cytochrome C in cytosol or mitochondria as well as that of Bax and Bcl-2 protein were evaluated by Western blot. Mitochondria-induced apoptosis was assayed by measuring mitochondrial membrane potential change. Production of general reactive oxygen species and mitochondrial superoxide in MM or CBL was detected after scutellarein treatment, which was reduced by MitoTEMPO or apocynin treatment, respectively. RESULTS: Scutellarein treatment showed potent cytotoxicity on MM cells but not on viable CBL, and intravenous injection of scutellarein significantly reduced MM xenograft tumor burden in nude mice. Scutellarein treatment in MM cells activated the mitochondrial-mediated intrinsic apoptosis pathway by increasing the production of mitochondrial superoxide, which was reduced to ROS by NADPH, but this effect was weakened in healthy CBL. Co-treatment with scutellarein synergized with bortezomib in inducing apoptosis in MM cells in vitro and in reducing tumor volume in MM xenografted nude mice. CONCLUSIONS: Scutellarein induced mitochondrial-mediated intrinsic apoptosis selectively on malignant cells comparing to healthy cells.

Vitexin alleviates streptozotocin-induced sexual dysfunction and fertility impairments in male mice via modulating the hypothalamus-pituitary-gonadal axis.

Diabetes-associated sexual dysfunction and fertility impairments are major secondary complications in diabetic patients and animal models. Natural herbs are important sources of therapeutic agents for diabetic complications. This study investigated the effect of vitexin on male sexual dysfunction and fertility impairments in streptozotocin (STZ)-induced diabetic mice. Diabetes was induced by intraperitoneal injection of 45 mg/kg STZ for 5 consecutive days in mice. Vitexin (10, 20 or 40 mg/kg) and Sildenafil citrate (SC, 5 mg/kg) were administered daily for 62 days after the induction of diabetes. The parameters of sexual behavior and fertility were analyzed. The reproductive organ weight, sperm motility, and viability of the treated mice were examined. Testicular histopathological alterations were detected by hematoxylin and eosin (H&E) staining. Enzyme-linked immunosorbent assay (ELISA) was used to evaluate serum hormonal levels. Results showed that 40 mg/kg vitexin significantly improved the sexual behavior and fertility levels compared with the diabetic group. Moreover, vitexin (20 or 40 mg/kg) significantly increased reproductive organ weight and improved testicular pathological structure damage. Meanwhile, sperm analysis demonstrated that vitexin significantly restored sperm quality in a dose-dependent manner. Furthermore, ELISA data showed that vitexin significantly increased the serum testosterone (T), follicular-stimulating hormone (FSH), and luteinizing hormone (LH) levels but decreased the gonadotropin-releasing hormone (GnRH) level to different degrees. These findings suggest that vitexin ameliorates sexual dysfunction and fertility impairments in male diabetic mice possibly by modulating the hypothalamus-pituitary-gonadal axis.

Synergistic Inhibitory Effects of Acacetin and 11 Other Flavonoids Isolated from Artemisia sacrorum on Lipid Accumulation in 3T3-L1 Cells.

Artemisia sacrorum Ledeb., a Compositae forage plant in China, has been found to have an inhibitory effect on lipid accumulation. We selected 12 flavonoids, which we had isolated from A. sacrorum and had the potential to inhibit lipid accumulation in the literature or in our preliminary experiments, and grouped them into 11 compound combinations; we investigated their synergistic inhibitory effects on lipid accumulation in 3T3-L1 cells. In screening experiments, Oil-Red O staining, triglyceride levels, and lipid accumulation levels all indicated that combined acacetin and apigenin displayed a significant synergistic inhibitory effect and the best repeatability. Subsequent research showed that this combination could synergistically promote the phosphorylations of AMPK and ACC. Furthermore, to a different extent, that combination had significant synergistic inhibitory effects on various genes or proteins related to adipogenesis and lipogenesis. Thus, that combination could significantly reduce triglyceride levels and lipid accumulation compared with acacetin or apigenin acting alone.

Apigenin suppresses PD-L1 expression in melanoma and host dendritic cells to elicit synergistic therapeutic effects.

BACKGROUND: The PD-L1/PD-1 pathway blockade-mediated immune therapy has shown promising efficacy in the treatment of multiple cancers including melanoma. The present study investigated the effects of the flavonoid apigenin on the PD-L1 expression and the tumorigenesis of melanoma. METHODS: The influence of flavonoids on melanoma cell growth and apoptosis was investigated using cell proliferation and flow cytometric analyses. The differential IFN-γ-induced PD-L1 expression and STAT1 activation were examined in curcumin and apigenin-treated melanoma cells using immunoblotting or immunofluorescence assays. The effects of flavonoid treatment on melanoma sensitivity towards T cells were investigated using Jurkat cell killing, cytotoxicity, cell viability, and IL-2 secretion assays. Melanoma xenograft mouse model was used to assess the impact of flavonoids on tumorigenesis in vivo. Human peripheral blood mononuclear cells were used to examine the influence of flavonoids on PD-L1 expression in dendritic cells and cytotoxicity of cocultured cytokine-induced killer cells by cell killing assays. RESULTS: Curcumin and apigenin showed growth-suppressive and pro-apoptotic effects on melanoma cells. The IFN-γ-induced PD-L1 upregulation was significantly inhibited by flavonoids, especially apigenin, with correlated reductions in STAT1 phosphorylation. Apigenin-treated A375 cells exhibited increased sensitivity towards T cell-mediated killing. Apigenin also strongly inhibited A375 melanoma xenograft growth in vivo, with enhanced T cell infiltration into tumor tissues. PD-L1 expression in dendritic cells was reduced by apigenin, which potentiated the cytotoxicity of cocultured cytokine-induced killer cells against melanoma cells. CONCLUSIONS: Apigenin restricted melanoma growth through multiple mechanisms, among which its suppression of PD-L1 expression exerted a dual effect via regulating both tumor and antigen presenting cells. Our findings provide novel insights into the anticancer effects of apigenin and might have potential clinical implications.

Scutellarin Ameliorates Learning and Memory Deficit via Suppressing ß-Amyloid Formation and Microglial Activation in Rats with Chronic Cerebral Hypoperfusion.

Chronic cerebral hypoperfusion is considered as a pivotal factor of cognitive impairment that occurs in cerebrovascular diseases. This study investigated the ameliorating effect of scutellarin (SCT) on spatial cognitive impairment and ß-amyloid (Aß) formation in rats with chronic cerebral hypoperfusion induced by permanent bilateral common carotid artery occlusion (pBCAO). SCT is a flavonoid in medicinal herb of Erigeron breviscapus (vant.) Hand. Mazz. known to have neuroprotective, antioxidative and anti-inflammatory effects. However, the beneficial effect and pivotal mechanism of SCT on cognitive impairment are still unclear. SCT was treated orally with two doses (10 or 30 mg/kg) for 4 weeks. Results of Morris water maze test performed on the ninth week after pBCAO revealed that SCT (30 mg/kg)-treated rats had significantly shortened escape latencies in acquisition training trials, significantly prolonged swimming time at the platform and its surrounding zone, significant increase in memory score, significant reduction in the number of target heading, and significant reduction in the time required for the first target heading during the retention trial compared to rats in the sham-control group. SCT significantly inhibited the production of Aß(1-40) and Aß(1­42) in brain tissues. However, SCT significantly upregulated the expression levels of amyloid precursor protein and ß-site APP-converting enzyme-1 in the hippocampus. In addition, SCT significantly inhibited the activation of Iba1-expressing microglia in brain tissues. The results suggest that SCT can exert ameliorating effect on spatial cognitive impairment caused by chronic cerebral hypoperfusion through suppressing Aß formation and microglial activation in brain tissues. Therefore, SCT can be used as a beneficial drug for vascular dementia and Alzheimer's disease.

Traversal of the Blood-Brain Barrier by Cleavable l-Lysine Conjugates of Apigenin.

Apigenin, a flavone abundant in parsley and celery, is known to act on several CNS receptors, but its very poor water solubility (<0.001 mg/mL) impedes its absorption in vivo and prevents clinical use. Herein, apigenin was directly conjugated with glycine, l-phenylalanine, and l-lysine to give the corresponding carbamate derivatives, all of which were much more soluble than apigenin itself (0.017, 0.018, and 0.13 mg/mL, respectively). The Lys-apigenin carbamate 10 had a temporary sedative effect on the mice within 5 min of intraperitoneal administration (single dose of 0.4 mg/g) and could be detected in the mice brain tissues at a concentration of 0.82 µg/g of intact Lys-apigenin carbamate 10 and 0.42 ug/g of apigenin at 1.5 h. This study accomplished the delivery of apigenin across the BBB in a manner that might be applicable to other congeners, which should inform the future development of BBB-crossing flavonoids.

Beneficial Effects of Different Flavonoids on Vascular and Renal Function in L-NAME Hypertensive Rats.

BACKGROUND: we have evaluated the antihypertensive effect of several flavonoid extracts in a rat model of arterial hypertension caused by chronic administration (6 weeks) of the nitric oxide synthesis inhibitor, L-NAME. METHODS: Sprague Dawley rats received L-NAME alone or L-NAME plus flavonoid-rich vegetal extracts (Lemon, Grapefruit + Bitter Orange, and Cocoa) or purified flavonoids (Apigenin and Diosmin) for 6 weeks. RESULTS: L-NAME treatment resulted in a marked elevation of blood pressure, and treatment with Apigenin, Lemon Extract, and Grapefruit + Bitter Orange extracts significantly reduced the elevated blood pressure of these animals. Apigenin and some of these flavonoids also ameliorated nitric oxide-dependent and -independent aortic vasodilation and elevated nitrite urinary excretion. End-organ abnormalities such as cardiac infarcts, hyaline arteriopathy and fibrinoid necrosis in coronary arteries and aorta were improved by these treatments, reducing the end-organ vascular damage. CONCLUSIONS: the flavonoids included in this study, specially apigenin, may be used as functional food ingredients with potential therapeutic benefit in arterial hypertension.

Scutellarin protects against vascular endothelial dysfunction and prevents atherosclerosis via antioxidation.

BACKGROUND: Scutellarin is the major constituent responsible for the clinical benefits of Erigeron breviscapus (Vant.) Hand.-Mazz which finds a long history of ethnopharmacological use in Traditional Chinese Medicine. Scutellarin as a pure compound is now under investigation for its protections against various tissue injuries. PURPOSE: This study aims to examine the effects of scutellarin on oxidative stress-induced vascular endothelial dysfunction and endothelial cell damage, and then to evaluate the therapeutic efficacy of scutellarin in preventing atherosclerosis in rats. METHODS: Radical scavenging ability of scutellarin was determined in vitro. Impact of scutellarin on endothelium-dependent relaxation (EDR) of rabbit thoracic aortic rings upon 1, 1-diphenyl-2-picrylhydrazyl (DPPH) challenge was measured. Influences of scutellarin pre-treatment on the levels of reactive oxygen species (ROS), activities of antioxidant enzymes superoxide dismutase (SOD), glutathione peroxidase and catalase, and the expression of SOD1 and NADPH oxidase 4 (Nox4) in human umbilical vein endothelial cells (HUVECs) injured by H2O2 were examined. Anti-atherosclerotic effect of scutellarin was evaluated in rats fed with high fat diet (HFD). RESULTS: Scutellarin showed potent antioxidant activity in vitro. Pretreatment of scutellarin retained the EDR of rabbit thoracic aortic rings damaged by DPPH. In H2O2 injured-HUVECs the deleterious alterations in ROS levels and antioxidant enzymes activity were reversed by scutellarin and the mRNA and protein expression of SOD1 and Nox4 were restored also. Oral administration of scutellarin dose-dependently ameliorated hyperlipidemia in HFD-fed rats and alleviated oxidative stress in rat serum, mimicking the effects of reference drug atorvastatin. CONCLUSION: Scutellarin protects against oxidative stress-induced vascular endothelial dysfunction and endothelial cell damage in vitro and prevents atherosclerosis in vivo through antioxidation. The results rationalize further investigation into the clinical use of scutellarin in cardiovascular diseases.

Isovitexin alleviates liver injury induced by lipopolysaccharide/d-galactosamine by activating Nrf2 and inhibiting NF-κB activation.

The aim of this study was to investigate the protective effects and mechanism of isovitexin, a glycosylflavonoid isolated from rice hulls of Oryza sativa, on Lipopolysaccharide (LPS)/d-galactosamine (D-Gal)-induced acute liver injury. The mice were randomly divided into five groups: control group, LPS/D-Gal group, and LPS/D-Gal + isovitexin groups. The mice of LPS/D-Gal group were received of LPS (50 µg/kg) and D-gal (800 mg/kg) intraperitoneal. The mice of LPS/D-Gal + isovitexin groups were received isovitexin (25, 50, 100 mg/kg) 1 h before LPS/D-Gal treatment. The results showed that the severity of liver injury was attenuated by treatment of isovitexin, as confirmed by the decreased liver histopathologic changes, as well as serum AST and ALT levels. Furthermore, the levels of TNF-α in serum and liver tissues, MPO activity and MDA content were significantly inhibited by isovitexin. In addition, isovitexin significantly attenuated NF-κB phosphorylation induced by LPS/D-Gal. The expression of Nrf2 and HO-1 were significantly up-regulated by isovitexin. In conclusion, isovitexin could protect against LPS/D-Gal-induced liver injury by inhibiting inflammatory and oxidative responses. Isovitexin also had protective effects against carbon tetrachloride (CCl4)-induced liver injury. Isovitexin may used as a potential agent for the treatment of liver injury.

Pharmacokinetic comparison of seven major bioactive components in normal and depression model rats after oral administration of Baihe Zhimu decoction by liquid chromatography-tandem mass spectrometry.

A simple and rapid liquid chromatography-tandem mass spectrometry method was firstly developed for simultaneous quantification of neomangiferin, mangiferin, regaloside A, regaloside I, timosaponin BII, anemarsaponin E and timosaponin AIII in rat plasma after oral administration of Baihe Zhimu decoction, which plays an important role for the treatment of depression. The plasma samples were pretreated by a one-step direct protein precipitation with methanol. Separation of the seven components and scutellarin (IS) from endogenous components with high selectivity and sensitivity (LLOQ, 0.1-1.0ng/mL) was achieved within 10min using Poroshell 120 EC-C18 column (150mm×3.0mm, 2.7µm). A gradient mobile phase consisting of acetonitrile and water (containing 5mM ammonium acetate) was applied at a flow rate of 0.4mL/min. Detection and measurement were performed on an AB Sciex QTRAP® 5500 mass spectrometer in multiple reactions monitoring mode. The intra- and inter-day precisions were all within 15% and the accuracies were in the range of -10.4% to 14.5%. The recovery ranged from 90.8 to 113.8%. The validated method was successfully applied to pharmacokinetic study of the seven components in normal and chronic unpredicted mild stress-induced depression model rats.

Apigenin, a novel candidate involving herb-drug interaction (HDI), interacts with organic anion transporter 1 (OAT1).

BACKGROUND: Apigenin is a flavonoid compound, widely distributed in natural plants. Various studies have suggested that apigenin has inhibitory effects towards several drug transporters, such as the organic anion transporting (OAT) polypeptides, 1B1 and 1B3 (OATP1B1 and OATP1B3). However, the mechanism by which apigenin interacts with OAT1 has not been well studied. METHODS: MDCK cells stably-expressing OAT1 were used to examine the inhibitory effects of apigenin on OAT1. UPLC-MS/MS was used to evaluate the in vitro and in vivo effects of apigenin on the uptake of acyclovir by OAT1. Cytotoxicity was determined by the cell viability, MTT assays. RESULTS: Apigenin effectively inhibited the activity of OAT1 in a dose-dependent manner with an IC50 value of 0.737µM. Pre-incubation of cells with apigenin caused a time-dependent inhibition (TDI) of OAT1. Additionally, we examined the interactions between apigenin and acyclovir or adefovir. Data showed that apigenin (1µM) significantly blocked the uptake of acyclovir by OAT1 in vitro with an inhibition rate of 55%. In vivo, apigenin could increase the concentration of acyclovir in plasma when co-administered with acyclovir. Importantly, the MTT assays showed that, at a dose of 50µM, apigenin significantly reduced the cytotoxicity of adefovir and substantially increased cell viability from 50.6% to 112.62%. CONCLUSION: Our results demonstrate that apigenin regulates OAT1, and can cause TDI or herb-drug interaction (HDI) when used in combination with acyclovir or adefovir. Therefore, apigenin could be used as a nephroprotective agent when used in combination with the substrates of OAT1.

Apigenin inhibits d-galactosamine/LPS-induced liver injury through upregulation of hepatic Nrf-2 and PPARγ expressions in mice.

Apigenin is a natural flavonoid compound widely distributed in a variety of vegetables, medicinal plants and health foods. This study aimed to examine the protective effect of apigenin against d-galactosamine (D-GalN)/lipopolysaccharide (LPS)-induced mouse liver injury and to investigate the potential biochemical mechanisms. The results showed that after oral administration of apigenin 100-200 mg/kg for 7 days, the levels of serum alanine aminotransferase and aspartate aminotransferase were decreased, and the severity of liver injury was alleviated. Importantly, apigenin pretreatment increased the levels of hepatic nuclear factor erythroid 2-related factor 2 (Nrf-2) and peroxisome proliferator-activated receptor γ (PPARγ) protein expressions as well as superoxide dismutase, catalase, glutathione S-transferase and glutathione reductase activities, decreased the levels of hepatic nuclear factor-κB (NF-κB) protein expression and tumor necrosis factor-α. These findings demonstrated that apigenin could prevent the D-GalN/LPS-induced liver injury in mice, and its mechanisms might be associated with the increments of Nrf-2-mediated antioxidative enzymes and modulation of PPARγ/NF-κB-mediated inflammation.