Safety and hematological toxicities of PARP inhibitors in patients with cancer: a systematic review of randomized controlled trials and a pharmacovigilance analysis.

INTRODUCTION: This study aimed to estimate the toxicities of PARP inhibitors (PARPis), based on randomized controlled trials (RCTs) and the FDA Adverse Event Reporting System (FAERS) database. METHODS: Four electronic databases were searched from inception to 16 April 2024, for RCTs of approved PARPis. The primary and secondary outcomes were grade 3-5 adverse events (AEs) and grade 3-5 hematological AE, respectively. We conducted network meta-analyses to calculate the relative risks (RRs) and 95% confidence intervals (CIs) of outcomes. A disproportionality analysis was conducted to estimate the signals of hematological AEs associated with PARPis from the FAERS database. RESULTS: Overall, 27 RCTs involving 11,067 patients with cancer were included. Olaparib had the best safety profile for any grade 3-5 AEs and hematological AEs among four approved PARPis. Olaparib did not increase the risk of thrombocytopenia (RR: 1.48; 95%CI: 0.64-3.39), but other PARPis did. Furthermore 14,780 hematological AE reports associated with PARPis were identified in the FAERS database, and all PARPis were associated with strong hematological AE signals. Hematological AEs mainly occurred within the first 3 months (80.84%) after PARPi initiation. CONCLUSION: Olaparib had the best safety profile among five PARPis. PARPi-associated hematological AEs mainly occurred within the first 3 months. REGISTRATION: PROSPERO (CRD42022385274).

Dose-sparing effect of lapatinib co-administered with a high-fat enteral nutrition emulsion: preclinical pharmacokinetic study.

Background: Lapatinib is an oral small-molecule tyrosine kinase inhibitor indicated for advanced or metastatic HER2-positive breast cancer. In order to reduce the treatment cost, a high-fat enteral nutrition emulsion TPF-T was selected as a dose-sparing agent for lapatinib-based therapies. This study aimed to investigate the effect of TPF-T on lapatinib pharmacokinetics. Methods: First, a simple and rapid liquid chromatography tandem mass spectrometry (LC-MS/MS) method was developed to quantitatively evaluate lapatinib in rabbit plasma. The method was fully validated according to the China Pharmacopoeia 2020 guidance. Rabbits and rats were chosen as the animal models due to their low and high bile flows, respectively. The proposed LC-MS/MS method was applied to pharmacokinetic studies of lapatinib, with or without TPF-T, in rabbit and rat plasma. Results: The LC-MS/MS method revealed high sensitivity and excellent efficiency. In the rabbit model, co-administration with TPF-T resulted in a 32.2% increase in lapatinib exposure. In the rat model, TPF-T had minimal influence on the lapatinib exposure. In both models, TPF-T was observed to significantly elevate lapatinib concentration in the absorption phase. Conclusion: Co-administration with TPF-T had a moderate effect on increasing exposure to lapatinib. Dose sparing using a high-fat liquid diet is potentially feasible for lapatinib-based therapies.

Correlation of gene expression profiles to identify pancreatic cancer cell lines that best model primary human tumors.

Background: Cancer cell lines are important research models for studying tumor biology in vivo. The accuracy of such studies is highly dependent on the phenotypic and genetic similarity of cell lines to patient tumors, but this is not always the case, particularly for pancreatic cancer. Methods: We compared the gene expression profiles of various pancreatic cancer cell lines and primary human pancreatic tumor tissues to determine which pancreatic cancer cell line best models human primary tumor. Profiles of messenger RNA (mRNA) expression of 33 pancreatic cancer cell lines and 892 patient samples of pancreatic adenocarcinoma (PAAD) were obtained from the Gene Expression Omnibus (GEO) database. Microarray data were normalized using the robust multichip average (RMA) algorithm and batch effect removal was performed using ComBat. The pooled data of each PAAD cell line were compared to patient tumors based on the top 2,000 genes with largest interquartile range (IQR), 134 gene-collections of cancer-related pathways, and 504 gene-collections of cancer-related functions using pairwise Pearson's correlation analysis. Results: PAAD cell lines were poorly correlated with patient tumor tissues based on the top 2,000 genes. Up to 50% of cancer-related pathways were not strongly recommended in PAAD cell lines, and a small proportion of cancer-related functions (12-17%) were poorly correlated with PAAD cell lines. In pan-pathway analysis, the cell lines showing the highest genetic correlation to patient tumors were Panc 03.27 for PAAD cell lines from a primary lesion site and CFPAC-1 for PAAD cell lines from a metastatic lesion site. In pan-function analysis, the cell lines showing the highest genetic correlation to patient tumors were Panc 03.27 for PAAD cell lines from a primary lesion site and Capan-1 for PAAD cell lines from a metastatic lesion site. Conclusions: The gene expression profiles of PAAD cell lines correlate weakly with those of primary pancreatic tumors. Through comparison of the genetic similarity between PAAD cell lines and human tumor tissue, we have provided a strategy for choosing the appropriate PAAD cell line.

Effectiveness and safety of extended thromboprophylaxis in post-discharge patients with COVID-19: A systematic review and meta-analysis.

BACKGROUND: The effect of extended thromboprophylaxis in improving the prognosis of adult patients with coronavirus disease 2019 (COVID-19) after discharge remains debatable. This meta-analysis was aimed to determine the advantages and disadvantages of extended thromboprophylaxis in these patients. METHODS: Different databases such as PubMed, Embase, Web of Science, and Cochrane Library were systematically searched for studies that evaluated the effects of extended thromboprophylaxis in post-discharge patients with COVID-19 until 13 June 2022. The primary efficacy outcome was defined by the composite outcome of thromboembolism and all-cause mortality, and the safety outcome was defined by bleeding events. The odds ratios (ORs) and 95 % confidence intervals (CIs) of efficacy and safety outcomes were calculated using fixed- or random-effects model. Interaction analysis was performed to assess and compare observational studies and randomised controlled trials (RCTs). A sensitivity analysis was performed after excluding studies of poor quality. RESULTS: Eight studies involving 10,148 patients were included. The results confirmed that extended thromboprophylaxis, primarily prophylactic use of anticoagulants for <35 days, was significantly associated with reduced composite outcome in high-risk post-discharge patients with COVID-19 (OR: 0.52; 95 % CI: 0.41-0.67, P = 0.000). Interaction analysis revealed that the effect estimates were consistent between the RCT and observational studies (Pinteraction = 0.310). Furthermore, extended thromboprophylaxis did not increase the risk of major bleeding events (OR: 1.64; 95 % CI: 0.95-2.82, P = 0.075). CONCLUSION: In post-discharge patients with COVID-19 at high risk of thromboembolism, extended thromboprophylaxis, primarily prophylactic use of anticoagulants for <35 days, can significantly reduce the risk of thrombosis and all-cause mortality without increasing the risk of major bleeding events. REGISTRATION: PROSPERO CRD42022339399.

Pirfenidone inhibits stromal collagen deposition and improves intra-tumoral delivery and antitumor efficacy of Pegylated liposomal doxorubicin.

The effectiveness of cancer nanotherapeutics is greatly restricted by the dense collagen network in solid tumors. Pirfenidone (PFD) is a clinically approved oral antifibrotic agent widely used to treat idiopathic pulmonary fibrosis. To investigate whether PFD can enhance the penetration and tumor delivery efficiency of Pegylated liposomal doxorubicin (PLD), colorectal cancer xenograft mice were administered PFD, PLD, or combined regimens. As expected, high-dose PFD (H-PFD, 270 mg/kg/day) combined with PLD (H-PFD + PLD) exhibited a significantly higher tumor inhibition rate than PLD monotherapy (75.09% vs. 60.87%). Similarly, the intra-tumoral doxorubicin level was markedly elevated using H-PFD pretreatment, which induced over 34% elevation compared to PLD treatment alone (3.37 ± 0.41 vs. 2.51 ± 0.19 µg/mL). Additionally, Masson's trichrome staining and immunohistochemistry results of the H-PFD + PLD group revealed an attenuation of collagen deposition in vivo, and the in vitro TGF-ß1, α-SMA, and collagen protein expression were inhibited using PFD treatment. In contrast, although low-dose PFD (60 mg/kg/day) did not present superior benefits in promoting PLD penetration into tumors, it did downregulate collagen expression in vivo. This study provides a new strategy for PFD combined with chemotherapeutic drugs to improve the antitumor efficacy of nanomedicines.

Pharmacist-led standardization of total parenteral nutrition improves postoperative nutritional status in colorectal cancer patients.

Background: Total parenteral nutrition (TPN) is an essential treatment for patients who undergo abdominal surgery. Due to the gap of knowledge background between clinicians and pharmacists, the participation of the latter may improve TPN standardization. However, the impact on clinical outcome is unknown. In this study, we evaluated the impact of appropriacy and efficacy of TPN prescription, after a pharmacist-led TPN standardization program introduced. Methods: A pharmacist-led TPN standardization program was introduced in the Zhejiang Cancer Hospital and the clinical outcomes were assessed. The TPN standardization program includes a pre-established standard multidisciplinary evaluation standard, a computerized TPN management system and regular evaluations of TPN prescription performed by pharmacists. Any concerns were identified and improved via discussed with doctors. To evaluate the effect of pharmacists' intervention in nutritional status and postoperative complications, an observational before-and-after cohort study was performed. All patients admitted in hospital with colorectal cancer (CRC) and receiving abdominal surgery in June 2019 (pre-intervention cohort) and June 2020 (post-intervention cohort) were retrospectively analyzed. Nutritional status of patients was evaluated using the levels of postoperative serum albumin, prealbumin, total protein, and their decrease extent. Surgical or TPN-related complications and recovery time were collated as the clinical outcomes. Results: There were no significant differences in the basic clinical information of the two cohorts, suggesting that the two groups are comparable. The average postoperative prealbumin levels were elevated in 2020 compared to 2019 (192.3±5.5 mg/L for 2019 and 229.5±4.8 mg/L for 2020, P<0.001). In addition, the post-intervention cohort showed a lower postoperative infection rate (11.6% vs. 18.2%), shorter duration of infection (9.4±1.4 vs. 7.7±1.0 days), lower incidence of postoperative albumin decrease (25.2% vs. 76.7%), prealbumin decrease (71.5% vs. 78.9%), and total protein decrease (25.2% vs. 72.2%), and lower incidence of TPN-related hypoglycemia (5.4% vs. 15.3%). Conclusions: Pharmacist-led TPN standardization improved the postoperative clinical outcomes in patients with colorectal cancer (CRC).

Pharmacist-Led Management Improves Treatment Adherence and Quality of Life in Opioid-Tolerant Patients With Cancer Pain: A Randomized Controlled Trial.

INTRODUCTION: Opioid-tolerant patients are more likely to deviate from recommended treatments and to experience inadequate analgesia than opioid-naive ones. The aim of this study was to examine whether pharmacist-led management could help improve treatment adherence and quality of life. METHODS: Eligible patients were randomized in a 1:1 ratio to control group and intervention group. The control group received routine education and support, while the intervention group received additional individualized pharmacist-led care. The primary endpoint was treatment adherence in the per-protocol analysis, as evaluated by blinded assessors. An interim analysis was planned when 30% patients completed the study. Alpha was divided into the interim analysis (0.015) and the final analysis (0.035). RESULTS: In the interim analysis (97 and 87 patients in the control and intervention groups, respectively), the primary endpoint was met. Pharmacist-led intervention significantly increased treatment adherence (93.3 vs. 79.8%; OR: 2.25; 95% CI 1.02, 4.94; P = 0.013), quality of life (0.81 ± 0.17 vs. 0.72 ± 0.25; P = 0.008), and reporting of adverse events (82.7 vs. 61.9%; OR: 1.88; 95% CI 1.16, 3.07; P = 0.004). The two groups did not differ in pain control rate (66.7 vs. 57.1%; OR: 1.25; 95% CI 0.87, 1.78; P = 0.218), breakthrough pain-free rate (66.7 vs. 61.9%; OR: 1.12; 95% CI 0.78, 1.59; P = 0.532) and pain score (1.97 ± 1.04 vs. 2.15 ± 1.24; P = 0.522). CONCLUSIONS: Pharmacist-led management improved treatment adherence, quality of life, and the reporting of adverse events in opioid-tolerant patients with cancer pain. TRIAL REGISTRATION: ClinicalTrials.gov, NCT03455023.

Comprehensive evaluation of the antioxidant capacity of Sceptridium ternatum using multiple colorimetric methods and 1,1-diphenyl-2-picrylhydrazyl-high-performance liquid chromatography analysis.

Sceptridium ternatum is a medicinal herb with multiple health benefits. However, its antioxidant activity and active components have not been clarified. In this study, the antioxidant capacity of S. ternatum was comprehensively investigated using multiple colorimetric methods and 1,1-diphenyl-2-picrylhydrazyl-high-performance liquid chromatography analysis. First, the phenolic content, flavonoid content, and radical scavenging ability of S. ternatum were parallelly determined using colorimetric methods performed in 96-well microplates. The flavonoid content, rather than the phenolic content, was highly correlated with its antioxidant activity. Sceptridium ternatum was shown to be a rich source of flavonoids, with a highest flavonoid yield of 3.44 ± 0.11 mg/g. Subsequently, 1,1-diphenyl-2-picrylhydrazyl-high-performance liquid chromatography experiment and quadrupole time-of-flight mass spectrometry analyses were carried out for rapid screening of the individual antioxidants. A total of 14 O-glycosyl flavonoids with quercetin or kaempferol aglycone have been characterized. Particularly, quercetin 3-O-rhamnoside-7-O-glucoside exhibited the most potent antioxidant ability. Its half-maximal effective concentrations for scavenging 1,1-diphenyl-2-picrylhydrazyl and 2,2'-azino-bis (3-ethylbenzthiazoline-6-sulfonic acid) radicals were 70.55 ± 2.69 and 106.90 ± 1.76 µg/mL, respectively, which were comparable with those of l-ascorbic acid. Our results indicated that the combined colorimetric and chromatographic methods provided a practical strategy for the discovery of bioactive compounds from natural products.

CN128: A New Orally Active Hydroxypyridinone Iron Chelator.

Deferoxamine, deferiprone, and deferasirox are used for the treatment of systemic iron overload, although they possess limitations due to lack of oral activity, lower efficacy, and side effects. These limitations led to a search for an orally active iron chelator with an improved therapeutic index. The lower efficacy of deferiprone is due to rapid glucuronidation, leading to the formation of a nonchelating metabolite. Here, we demonstrate that the influence of metabolism can be reduced by introducing a sacrificial site for glucuronidation. A log P-guided investigation of 20 hydroxpyridinones led to the identification of CN128. The Fe(III) affinity and metal selectivity of CN128 are similar to those of deferiprone, the log P value is more lipophilic, and its iron scavenging ability is superior. Overall, CN128 was demonstrated to be safe in a range of toxicity assessments and is now in clinical trials for the treatment of ß-thalassemia after regular blood transfusion.

Multidisciplinary intervention incorporating pharmacists in management of opioid-naïve patients with moderate to severe cancer pain.

OBJECTIVE: This study aims to investigate the impact of intervention of multidisciplinary team incorporating pharmacists for management of opioid-naïve patients with moderate to severe cancer pain. METHODS: A retrospective cohort study was conducted to compare pre- and post-multidisciplinary intervention groups in opioid-naïve patients with moderate to severe cancer pain. Primary outcome was the proportions of appropriate pain assessment and opioid titration. Secondary outcomes were pain intensity (PI), length of hospital stay, opioid escalation index percentage (OEI%) and incidences of opioid-related adverse events. RESULTS: A total of 400 patients were included in the study (pre-intervention, n = 200; post-intervention, n = 200). Continuous improvement in pain assessment and titration was recorded after intervention. Though no substantial differences existed between groups in PI on the day of discharge, post-intervention group was associated with reduced length of hospital stay as well as decreased proportion of subjects with OEI% >5%. As for safety, significant decreases in constipation and vomiting were seen. CONCLUSION: Findings suggest that interventions of multidisciplinary team incorporating pharmacists could improve cancer pain management for opioid-naïve patients. Pharmacists should be considered as an important member of a multidisciplinary team in good pain management.

Asiatic acid enhances intratumor delivery and the antitumor effect of pegylated liposomal doxorubicin by reducing tumor-stroma collagen.

Tumor-targeted drug delivery systems (Tt-DDSs) are proposed as a promising strategy for cancer care. However, the dense collagen network in tumors stroma significantly reduces the penetration and efficacy of Tt-DDS. In order to investigate the effect of asiatic acid (AA) on antitumor effect of pegylated liposomal doxorubicin (PLD) by attenuating stroma-collagen, colon cancer xenograft mice (SW620 cell line) were treated by PLD, AA, or combined regimes, respectively; the collagen levels were estimated by Sirius red/fast green dual staining and immunohistochemistry (IHC) staining; the intratumor exposure of doxorubicin was visualized by ex vivo fluorescence imaging and quantified by HPLC/MS analysis. In addition, the impact of AA on collagen synthesis of fibroblast cell (HFL-1) and cytotoxic effect of PLD and doxorubicin to cancer cell (SW620) were studied in vitro. In the presence of AA (4 mg/kg), the intratumor collagen level was restricted in vivo (reduced by 22%, from 4.14% ± 0.30% to 3.24% ± 0.25%, P = 0.051) and in vitro. Subsequently, doxorubicin level was increased by ~30%. The antitumor activity of PLD was significantly improved (57.3% inhibition of tumor growth and 44% reduction in tumor weight) by AA combination. Additionally, no significant improvement in cytotoxic effect of PLD or doxorubicin induced by AA was observed. In conclusion, AA is a promising sensitizer for tumor treatment by enhancing intratumor drug exposure via stromal remodeling.

Dual-negative expression of Nrf2 and NQO1 predicts superior outcomes in patients with non-small cell lung cancer.

Functional studies in non-small cell lung cancer (NSCLC) patients revealed that hyperactivation of the NF-E2-related factor 2 (Nrf2) pathway facilitates tumor growth. We examined the usefulness of Nrf2 and NQO1 as indicators of prognosis in NSCLC. Tumor and adjacent non-tumor tissue samples were collected from 215 NSCLC patients who had tumor resections between 2006 and 2011. Immunohistochemistry was performed to detect Nrf2 or NQO1 expression. The correlation between Nrf2 or NQO1 expression and survival outcomes was evaluated using the Kaplan-Meier method and Cox proportional hazards regression model. Levels of Nrf2 and NQO1 were elevated in tumor tissues. In particular, Nrf2 was elevated in nearly all tumor cells. NQO1 expression positively correlated with Nrf2 expression (P = 0.039). Nrf2 expression positively correlated with lymph node metastasis (P = 0.001) and negatively correlated with tumor differentiation (P = 0.032). As compared with either Nrf2 or NQO1 alone, dual-negative expression of Nrf2 and NQO1 was more predictive of superior overall survival (P = 0.020) and disease free survival (P = 0.037). Subgroup analyses showed that females, nonsmokers, and patients with advanced-stage NSCLC were suitable populations in which to evaluate prognosis based on Nrf2 and NQO1 co-expression. These results indicate that dual-negative expression of Nrf2 and NQO1 is predictive of a better prognosis in NSCLC patients.

Methylation of the Constitutive Androstane Receptor Is Involved in the Suppression of CYP2C19 in Hepatitis B Virus-Associated Hepatocellular Carcinoma.

Hepatocellular carcinoma (HCC), one of the most dangerous malignancies with an increasing incidence and a high mortality rate, represents a major international health problem. HCC progression is known to involve genome-wide alteration of epigenetic modifications, leading to aberrant gene expression patterns. The activity of CYP2C19, an important member of the cytochrome P450 superfamily, was reported to be compromised in HCC, but the underlying mechanism remains unclear. To understand whether epigenetic modification in HCC is associated with a change in CYP2C19 activity, we evaluated the expression levels of CYP2C19 and its transcription factors by quantitative real-time polymerase chain reaction using mRNA extracted from both primary hepatocytes and paired tumor versus nontumor liver tissues of patients infected with hepatitis B virus (HBV). DNA methylation was examined by bisulfite sequencing and methylation-specific polymerase chain reaction. Our results indicated that CYP2C19 could be regulated by e-box methylation of the constitutive androstane receptor (CAR). Decreased CYP2C19 expression in tumorous tissues of HBV-infected patients with HCC was highly correlated with suppressed expression and promoter hypermethylation of CAR. Our study demonstrates that aberrant CAR methylation is involved in CYP2C19 regulation in HBV-related HCC and may play a role in liver tumorigenesis.

[In vitro interaction of deferiprone with cellular membrane transporters of hOCTs and hOAT1].

OBJECTIVE: To develop a LC-MS/MS method for determination of deferiprone in cell lysate and to study the potential interaction between deferiprone and hOCTs or hOAT1 transporters in vitro. METHODS: The determination was performed on an Agilent Eclipse Plus C18 column(3.5 µm, 2.1 mm×50 mm).The gradient mobile phase was composed of solvent A:0.1% formic acid in water, and B:0.1% formic acid in acetonitrile. The mass spectrometer with an electrospray interface was operated in positive ion mode with multiple reaction monitoring (MRM) scan mode monitored the ion pair of deferiprone at m/z 140→96, or phenacetin at m/z 180→110. The effects of deferiprone on the accumulation of typical substrates of hOCTs and hOAT1 were evaluated by MDCK-hOCTs and MDCK-hOAT1 cells respectively. The accumulation of deferiprone was also investigated in MDCK-hOCTs cells and mock cells with or without typical inhibitors. RESULTS: The standard curve was linear over the range of 5-300 nmol/L. The assay recovery of deferiprone was above 94%, and the intra-day precision (RSD) was less than 2.0%. The accumulation of MPP(+) in MDCK-hOCTs cells with 300 µmol/L deferiprone were 73.5%, 87.1% and 70.4%, respectively. The uptake of deferiprone in MDCK-hOCTs and mock cells did not show significant difference. Deferiprone of 100 µmol/L did not significantly affect the accumulation of 6-CF in MDCK-hOAT1 cell. CONCLUSION: The method is sensitivity and suitable for the determination of deferiprone in cell lysate. Deferiprone can significantly inhibit hOCT1 and hOCT3, but has no effects on hOCT2 and hOAT1. hOCTs may not play a major role in the transport of deferiprone.

Luteolin is a rare substrate of human catechol-O-methyltransferase favoring a para-methylation.

SCOPE: The study aimed to investigate the regioselectivity of methylation of luteolin (3',4',5,7-tetrahydroxyflavone) in human in vitro and in vivo. METHODS AND RESULTS: Recombinant human catechol-O-methyltransferase (COMT) and human liver S9 were utilized to study the kinetics of meta (3')- and para (4')- methylation of luteolin, and urine samples from volunteers after giving a luteolin-containing formulation were collected to determine the ratio of para-/meta-production. The results showed luteolin favored a para-methylation, with a ratio of of para-/meta-production in CLint (1.43 in recombinant human COMT and 1.47 in human liver S9), which was contrary to the known substrates of COMT. However, the result of urine sample assay showed a preference of meta-methylation with a ratio of of para-/meta-production (0.460 ± 0.126). To elucidate the mechanism for different preference of methylation of luteolin in vitro and in vivo, metabolism stability of the meta- and para-methylated luteolin was evaluated in human liver microsomes and recombinant human CYP450s, which revealed that para-methylated luteolin was more easily demethylated by human CYP1A2 and CYP3A4/5 than meta-methylated luteolin. CONCLUSION: Luteolin was a rare substrate of human COMT favoring a para-methylation, but further demethylation by human CYP1A2 and CYP3A4/5 caused a preference of accumulation in meta-methylated luteolin in vivo.

Pharmacokinetic study of luteolin, apigenin, chrysoeriol and diosmetin after oral administration of Flos Chrysanthemi extract in rats.

Flos Chrysanthemi (the flower of Chrysanthemum morifolium Ramat.) is widely used in China as a food and traditional Chinese medicine for many diseases. Luteolin and apigenin are two main bioactive components in Flos Chrysanthemi, and chrysoeriol and diosmetin are two methylated metabolites of luteolin in vivo by cathechol-O-methyltransferase (COMT). However, there was lack of pharmacokinetic information of chrysoeriol and diosmetin after oral administration of Flos Chrysanthemi extract (FCE). The present study aimed to develop an HPLC-UV method for simultaneous determination of rat plasma concentration of luteolin, apigenin, chrysoeriol and diosmetin and utilize it in pharmacokinetic study of the four compounds after orally giving FCE to rats. The method was successfully validated and applied to the pharmacokinetic study when oral administration of FCE to rats with or without co-giving a COMT inhibitor, entacapone. Chrysoeriol and diosmetin were detected in rat plasma after oral administration of FCE and their concentrations were significantly decreased after co-giving entacapone. Furthermore, AUC of luteolin was significantly increased by entacapone, while that of chrysoeriol was decreased by entacapone, which revealed COMT might play an important role in the disposition of luteolin in rats after dosing of FCE. In conclusion, a sensitive, accurate and reproducible HPLC-UV method for simultaneous determination of luteolin, apigenin, chrysoeriol and diosmetin in rat plasma were developed, pharmacokinetics of chrysoeriol and diosmetin combined with luteolin and apigenin were characterized after oral administration of FCE to rats, which gave us more information on pharmacokinetics and potential pharmacological effects of FCE in vivo.

The exposure of luteolin is much lower than that of apigenin in oral administration of Flos Chrysanthemi extract to rats.

Luteolin (3',4',5,7-tetrahydroxyflavone) and apigenin (4',5,7-trihydroxyflavone) are two common flavones and major bioactive components in Flos Chrysanthemi extract (FCE). Although FCE contains approximately equal amounts of luteolin (6.5%, w/w) and apigenin (5.4%, w/w), luteolin showed a much lower exposure than apigenin when FCE was orally administered to rats. The aim of the present study is to elucidate the mechanisms that caused the pharmacokinetic difference between luteolin and apigenin in rats. The results of an in situ rat intestinal single-pass perfusion model showed that the permeability of luteolin (k(a), 7.96×10⁻² min⁻¹ and P(eff), 4.87×10⁻³ cm/min) was about 50% that of apigenin (k(a), 18.5×10⁻² min⁻¹ and P(eff), 10.8×10⁻³ cm/min), which agreed with the observation that oral bioavailability of luteolin (30.4%) from FCE was significantly lower than that of apigenin (51.1%). On the other hand, luteolin was much more unstable than apigenin during the incubation with primary rat hepatocytes, and methylated metabolites of luteolin were detected after incubation. In addition, further metabolism of methylated luteolin also contributed to the faster elimination of luteolin. In conclusion, luteolin and apigenin are very similar in structure, however, one-hydroxyl difference gives them different characteristics in absorption and metabolism, which results in much lower exposure of luteolin than apigenin when FCE is orally administered to rats.

Promoting effects of isobavachin on neurogenesis of mouse embryonic stem cells were associated with protein prenylation.

AIM: Some small molecules can induce mouse embryonic stem (ES) cells to differentiate into neuronal cells. Here, we explored the effect of isobavachin (IBA), a compound with a prenyl group at position 8 of ring A, on promoting neuronal differentiation and the potential role of its protein prenylation. METHODS: The hanging drop method was employed for embryonic body (EB) formation to mimic embryo development in vivo. The EBs were treated with IBA at a final concentration of 10(-7) mol/L from EB stage (d 4) to d 8+10. Geranylgeranyltransferase I inhibitor GGTI-298 was subsequently used to disrupt protein prenylation. Neuronal subtypes, including neurons and astrocytes, were observed by fluorescence microscopy. Gene and protein expression levels were detected using RT-PCR and Western blot analysis, respectively. RESULTS: With IBA treatment, nestin was highly expressed in the neural progenitors generated from EBs (d 4, d 8+0). EBs then further differentiated into neurons (marked by ß-tubulin III) and astrocytes (marked by GFAP), which were both up-regulated in a time-dependent manner on d 8+5 and d 8+10. Co-treatment with GGTI-298 selectively abolished the IBA-induced neuronal differentiation. Moreover, in the MAPK pathway, p38 and JNK phosphorylation were down-regulated, while ERK phosphorylation was up-regulated after IBA treatment at different neuronal differentiation passages. CONCLUSION: IBA can facilitate mouse ES cells differentiating into neuronal cells. The mechanism involved protein prenylation and, subsequently, phos-ERK activation and the phos-p38 off pathway.