Publications by authors named "Daiki Yamashita"

16 Publications

  • Page 1 of 1

Cryoballoon ablation for atrial fibrillation without the use of a contrast medium: a combination of the intracardiac echocardiography and pressure wave monitoring guided approach.

Heart Vessels 2021 Oct 12. Epub 2021 Oct 12.

Department of Cardiology, Nagoya University Graduate School of Medicine, Nagoya, Aichi, Japan.

In cryoballoon ablation (CBA), a contrast medium is commonly used to confirm balloon occlusion of the pulmonary veins (PVs). However, a contrast medium cannot always be used in patients with renal dysfunction and allergy. The present study aimed to assess the efficacy and safety of CBA without the use of a contrast medium. We retrospectively examined consecutive patients with paroxysmal atrial fibrillation (PAF) who underwent first-time CBA. We compared the procedural results and outcomes in patients for whom a contrast medium was used (contrast group) and those from whom a contrast medium was not used (non-contrast group). In the non-contrast group, we used saline injection on the intracardiac echocardiography and pressure wave monitoring for PV occlusion. Fifty patients (200 PVs) and 22 patients (88 PVs) underwent CBA with and without a contrast medium, respectively. The success rate of PV isolation with CBA alone was 93% and 90% in the non-contrast and contrast groups, respectively (p = 0.40). The fluoroscopy time and nadir temperature were significantly lower in the non-contrast group as compared to that in the contrast group. The recurrence rate 1 year after ablation did not differ between the two groups (18% vs. 18%, p > 0.99). Furthermore, the number of reconnected PVs in patients with recurrence was significantly lower in the non-contrast group than in the contrast group (6% vs. 36%, p = 0.017). In conclusion, CBA using the intracardiac echocardiography and pressure monitoring approach without the use of a contrast medium was safe and efficient.
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http://dx.doi.org/10.1007/s00380-021-01963-3DOI Listing
October 2021

Earliest pulmonary vein potential-guided cryoballoon ablation is associated with better clinical outcomes than conventional cryoballoon ablation: A result from two randomized clinical studies.

J Cardiovasc Electrophysiol 2021 Sep 17. Epub 2021 Sep 17.

Department of Cardiology, Nagoya University Graduate School of Medicine, Nagoya, Aichi, Japan.

Introduction: With regard to short-term outcome in atrial fibrillation (AF), the benefit of cryoballoon ablation (CBA) by pressing a balloon against the earliest pulmonary vein (PV) potential site during PV isolation (earliest potential [EP]-guided CBA) has been previously demonstrated. The present study aimed to evaluate the long-term outcome of the EP-guided CBA.

Methods And Results: This study included 136 patients from two randomized studies, who underwent CBA for paroxysmal AF for the first time. Patients were randomly assigned to the EP-guided and conventional CBA groups in each study. In the EP-guided CBA group, we pressed a balloon against the EP site when the time-to-isolation (TTI) after cryoapplication exceeded 60 and 45 s in the first and second studies, respectively. We compared the clinical outcomes for 1 year after the procedure between the EP-guided CBA group (68 patients) and the conventional CBA group (68 patients). The primary endpoint was the recurrence of atrial arrhythmia after ablation. No significant differences in baseline characteristics were observed between the two groups. Compared with the conventional CBA group, the EP-guided CBA group had a significantly higher success rate at TTI ≤ 90 s (98.5% vs. 90.0%, p < .001); lower touch-up rate and total cryoapplication; and shorter procedure time, and fluoroscopy time. The recurrence at 1 year after ablation was significantly lower in the EP-guided CBA group than in the conventional CBA group (6.0% vs. 19.4%; p = .019).

Conclusions: The EP-guided CBA approach can facilitate the ablation procedure and achieve low recurrence at 1 year after ablation.
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http://dx.doi.org/10.1111/jce.15246DOI Listing
September 2021

Acute pancreatitis following allogeneic hematopoietic stem cell transplantation in children.

Int J Hematol 2021 Oct 21;114(4):494-501. Epub 2021 Jul 21.

Department of Hematology and Oncology, Children's Medical Center, Japanese Red Cross Nagoya First Hospital, 3-35 Michishita-cho, Nakamura-ku, Nagoya, 453-8511, Japan.

Acute pancreatitis (AP) is a potential complication of hematopoietic stem cell transplantation (HSCT), but its incidence and risk factors remain unclear. Thus, we reviewed the cases of 259 consecutive children who received allogeneic HSCT at our institution between January 2000 and December 2017 to determine the incidence and risk factors of AP. Thirteen patients developed AP during a median follow-up period of 4.4 years. The median time from HSCT to AP onset was 80 days (range 29-2426 days), and cumulative incidence (CI) at 4 years was 5.0% [95% confidence interval (95% CI) 2.7-8.3%]. The CI of AP was significantly higher in patients who received bone marrow or peripheral blood stem cells than in those who received cord blood (7.2% versus 0.0% at 4 years, P = 0.02) and was higher in patients who developed grade II-IV acute graft-versus-host disease (GVHD) than in those who did not (31.4% versus 1.4% at 4 years, P < 0.001). Multivariate analysis showed that grade II-IV acute GVHD was an independent risk factor for AP [hazard ratio 15.2 (95% CI 4.1-55.8), P < 0.001] and was strongly associated with post-HSCT AP in children.
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http://dx.doi.org/10.1007/s12185-021-03195-7DOI Listing
October 2021

Detection of negatively ionized air by using a Raman silicon nanocavity laser.

Opt Express 2021 May;29(11):16228-16240

The performance of a Raman silicon laser based on a high quality-factor nanocavity depends on the degree of free-carrier absorption, and this characteristic may be useful for certain applications. Here we demonstrate that laser oscillation in a Raman silicon nanocavity laser stops abruptly after an exposure to a weak flux of negatively ionized air for a few seconds. Spectral measurements reveal that the laser interruption is mainly caused by the transfer of extra electrons from the negatively ionized air molecules to the silicon nanocavity. These electrons affect the efficiency of the Raman laser by free carrier absorption. We find that the laser output gradually recovers as the extra electrons escape from the nanocavity and confirm that such a detection of ionized air is repeatable. These results show that a Raman silicon nanocavity laser can be used for the detection of ionized air with a high spatial resolution.
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http://dx.doi.org/10.1364/OE.423475DOI Listing
May 2021

Deterministic transfer of optical-quality carbon nanotubes for atomically defined technology.

Nat Commun 2021 May 25;12(1):3138. Epub 2021 May 25.

Nanoscale Quantum Photonics Laboratory, RIKEN Cluster for Pioneering Research, Saitama, Japan.

When continued device scaling reaches the ultimate limit imposed by atoms, technology based on atomically precise structures is expected to emerge. Device fabrication will then require building blocks with identified atomic arrangements and assembly of the components without contamination. Here we report on a versatile dry transfer technique for deterministic placement of optical-quality carbon nanotubes. Single-crystalline anthracene is used as a medium which readily sublimes by mild heating, leaving behind clean nanotubes and thus enabling bright photoluminescence. We are able to position nanotubes of a desired chirality with a sub-micron accuracy under in-situ optical monitoring, thereby demonstrating deterministic coupling of a nanotube to a photonic crystal nanobeam cavity. A cross junction structure is also designed and constructed by repeating the nanotube transfer, where intertube exciton transfer is observed. Our results represent an important step towards development of devices consisting of atomically precise components and interfaces.
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http://dx.doi.org/10.1038/s41467-021-23413-4DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8149403PMC
May 2021

Impact of the clinical frailty scale on clinical outcomes and bleeding events in patients with ST-segment elevation myocardial infarction.

Heart Vessels 2021 Jun 7;36(6):799-808. Epub 2021 Jan 7.

Department of Cardiology, Nagoya University Graduate School of Medicine, Nagoya, Japan.

The Clinical Frailty Scale (CFS) is a simple tool to assess patients' frailty and may help to predict adverse outcomes in elderly patients. The aim of the present study was to examine the impact of CFS on clinical outcomes and bleeding events after successful percutaneous coronary intervention (PCI) in ST-segment elevation myocardial infarction (STEMI). We enrolled 266 consecutive patients with STEMI who underwent primary PCI in between January 2015 and June 2018. Patients were categorized into two groups based on the CFS stages: CFS 1-3 and CFS ≥ 4. We collected the data and evaluated the relationship between the CFS grade and the incidence of major adverse cardiovascular events (MACE) and Bleeding Academic Research Consortium 3 or 5 bleeding events. Of these patients, CFS ≥ 4 was present in 59 (22.2%). During the follow-up, 37.3% in the CFS ≥ 4 group and 8.2% in the CFS 1-3 group experienced MACE. In Kaplan-Meier analysis, the proportion of MACE-free survival for 4 years was significantly lower in the CFS ≥ 4 group (log-rank P < 0.001). Additionally, the proportion of bleeding event-free survival was significantly lower in the CFS ≥ 4 group (log-rank P < 0.001). The CFS (per 1-grade increase) remained an independent significant predictor of MACE on multivariate Cox proportional hazard analysis [hazard ratio 1.39 (95% confidence interval: 1.08 to 1.79, P = 0.01)]. In conclusion, CFS was an independent predictor of future adverse cardiac events in patients with STEMI. Therefore, the assessment of CFS is crucial in this population.
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http://dx.doi.org/10.1007/s00380-020-01764-0DOI Listing
June 2021

Correlation of the peak oxygen consumption and ventilatory aerobic threshold by cardiopulmonary exercise testing with atrial fibrillation recurrences after ablation in patients with paroxysmal atrial fibrillation.

J Arrhythm 2020 Jun 5;36(3):456-463. Epub 2020 May 5.

Cardiovascular Center Okayama Heart Clinic Okayama Japan.

Background: The cardiopulmonary function is hypothesized to be associated with atrial fibrillation/atrial tachyarrhythmia (AF/AT) recurrence after AF ablation.

Purpose: To clarify the relationship between the cardiopulmonary function after successful ablation and AF/AT recurrence.

Methods: We examined 31 patients with paroxysmal AF who underwent AF ablation. Cardiopulmonary exercise testing (CPET) was performed at 1month after the ablation. A continuously increasing loading method on a bicycle ergometer was employed for the CPET.

Results: No adverse events, including AF/AT recurrence, occurred during the CPET. Among 31 patients, AT/AF recurrence was observed in seven (23%). The ventilatory anaerobic threshold (VAT) and peak oxygen consumption (VO2) were significantly higher in patients without AF/AT recurrence than in those with AT/AF recurrences (peak VO2 23.6 ± 5.7 vs 17.2 ± 4.1 mL/kg/min; VAT, 16.7 ± 2.8 vs 13.8 ± 2.7 mL/min/kg). The areas under the receiver operating characteristic curve for the peak VO2 and VAT were 0.786 ( < .01) and 0.789( < .01), respectively. Both indices had a sensitivity of 70%-80% and specificity of 70%-80% for predicting AT/AF recurrence. Similar results were obtained for the percent values of the predicted peak VO2 and VAT.

Conclusions: The present pilot study found that CPET can be performed safely at approximately 1 month after AF ablation. The peak VO2 and VAT were significantly associated with AT/AF recurrence. The peak VO2 and VAT were thought to provide helpful information regarding AT/AF recurrence.
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http://dx.doi.org/10.1002/joa3.12350DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7280009PMC
June 2020

Population Pharmacokinetic Analysis of Phenytoin After Intravenous Administration of Fosphenytoin in Adult and Elderly Epileptic Patients.

Ther Drug Monit 2019 10;41(5):674-680

Department of Clinical Pharmacokinetics, Graduate School of Pharmaceutical Sciences, Kyushu University.

Background: Fosphenytoin, the diphosphate ester salt of phenytoin, is widely used to treat status epilepticus. The aim of this study was to develop a population pharmacokinetic (PPK) model to describe serum phenytoin concentrations after the intravenous administration of fosphenytoin in adult and elderly epileptic patients.

Methods: Patient backgrounds, laboratory tests, and prescribed drugs were retrospectively collected from electronic medical records. Patients who received fosphenytoin were enrolled. The PPK analysis was performed using NONMEM 7.3.0 with the first-order conditional estimation method with interaction. Age, sex, laboratory tests, and coadministered drugs were selected as candidates for covariates. Significance levels for forward inclusion and backward elimination were set at 0.05 and 0.01, respectively. The study protocol was approved by the Fukuoka Tokushukai Ethics Committee.

Results: A total of 340 serum phenytoin concentrations from 200 patients treated with fosphenytoin were available. The median age and body weight of the population were 71 years and 53.4 kg, respectively. A linear 1-compartment model with the conversion rate of fosphenytoin to phenytoin clearly described the pharmacokinetics of phenytoin after the intravenous administration of fosphenytoin. Age was detected as a covariate of clearance (CL): CL (L/h) = 1.99 × (body weight/53.4) × (age/71). Goodness-of-fit plots revealed the high-predictive performance of the final PPK model, and systematic deviations were not observed. The final model was validated by a prediction-corrected visual predictive check and bootstrap analysis.

Conclusions: We herein developed a PPK model to describe phenytoin concentrations after the intravenous administration of fosphenytoin. Age was identified as a significant covariate for CL.
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http://dx.doi.org/10.1097/FTD.0000000000000651DOI Listing
October 2019

Population Pharmacodynamic Analysis of Uric Acid-Lowering Effects of Febuxostat Based on Electronic Medical Records in Two Hospitals.

J Clin Pharmacol 2018 03 18;58(3):304-313. Epub 2017 Oct 18.

Department of Clinical Pharmacokinetics, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan.

The aim of this study was to develop a population pharmacodynamic (PPD) model to describe uric acid (UA)-lowering effects in patients treated with febuxostat based on electronic medical records in 2 independent hospitals (university and city hospitals). Interhospital differences in the PPD model were also evaluated. We conducted the following 2 approaches to build the PPD models. A PPD model was developed separately using individual hospital data, and structural models and covariates between the two hospitals were compared (approach A). Another PPD model was developed using all available data from both hospitals, and differences between the 2 hospitals were evaluated by performing a covariate analysis on all PPD parameters (approach B). PPD analyses were performed by NONMEM using data from 358 patients. In both approaches, one indirect response model was established. In approach A, 2 diuretics (loops and thiazides) and renal function tests (Scr or BUN) were selected as covariates for the UA baseline level (serum UA levels just before the febuxostat treatment), whereas 2 diuretics and BUN were selected in approach B. A covariate analysis indicated that loops and thiazides increased UA baseline levels by 7%-14% and 6%-11%, respectively. In approach B, "hospital" was identified as a significant covariate for the UA baseline level; the baseline level was 7% higher in the city hospital. A PPD analysis may provide a precise description of the time course of the UA-lowering effects of febuxostat and quantitatively detect an interhospital difference in the UA baseline level.
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http://dx.doi.org/10.1002/jcph.1023DOI Listing
March 2018

DRESS Syndrome Caused by Cross-reactivity Between Vancomycin and Subsequent Teicoplanin Administration: A Case Report.

Am J Case Rep 2016 Aug 30;17:625-31. Epub 2016 Aug 30.

Department of Pharmaceutical Care and Health Sciences, Faculty of Pharmaceutical Sciences, Fukuoka University, Fukuoka, Japan.

BACKGROUND Drug reaction with eosinophilia and systemic symptoms (DRESS) syndrome is a potentially life-threatening syndrome comprising severe skin eruption, fever, eosinophilia, lymphadenopathy, and involvement of internal organs. Here, we describe a case of DRESS syndrome caused by cross-reactivity between vancomycin and subsequent teicoplanin administration. CASE REPORT A 79-year-old male was admitted to our hospital for the treatment of injuries incurred in a traffic accident. Eosinophilia and lung dysfunction appeared after vancomycin administration. These symptoms were improved temporarily by withdrawal of vancomycin and administration of corticosteroid, but exacerbated by subsequent teicoplanin administration. These symptoms disappeared after discontinuation of teicoplanin. Based on comprehensive assessment of the overall clinical course, we judged that DRESS syndrome was induced by cross-reactivity between vancomycin and subsequent teicoplanin administration. Using the European Registry of Severe Cutaneous Adverse Reactions (RegiSCAR) scoring system, we categorized DRESS syndrome related to vancomycin and teicoplanin as "probable." We describe, for the first time, DRESS syndrome (defined using the RegiSCAR scoring system) caused by cross-reactivity between vancomycin and subsequent teicoplanin administration. CONCLUSIONS Clinicians should be aware that DRESS syndrome can be induced by cross-reactivity between vancomycin and teicoplanin.
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http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5012458PMC
http://dx.doi.org/10.12659/ajcr.899149DOI Listing
August 2016

Charge Injection at the Heterointerface in Perovskite CH3NH3PbI3 Solar Cells Studied by Simultaneous Microscopic Photoluminescence and Photocurrent Imaging Spectroscopy.

J Phys Chem Lett 2016 Aug 4;7(16):3186-91. Epub 2016 Aug 4.

Institute for Chemical Research, Kyoto University , Uji, Kyoto 611-0011, Japan.

Charge carrier dynamics in perovskite CH3NH3PbI3 solar cells were studied by means of microscopic photoluminescence (PL) and photocurrent (PC) imaging spectroscopy. The PL intensity, PL lifetime, and PC intensity varied spatially on the order of several tens of micrometers. Simultaneous PL and PC image measurements revealed a positive correlation between the PL intensity and PL lifetime, and a negative correlation between PL and PC intensities. These correlations were due to the competition between photocarrier injection from the CH3NH3PbI3 layer into the charge transport layer and photocarrier recombination within the CH3NH3PbI3 layer. Furthermore, we found that the decrease in the carrier injection efficiency under prolonged light illumination leads to a reduction in PC, resulting in light-induced degradation of solar cell devices. Our findings provide important insights for understanding carrier injection at the interface and light-induced degradation in perovskite solar cells.
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http://dx.doi.org/10.1021/acs.jpclett.6b01231DOI Listing
August 2016

Raman shift and strain effect in high-Q photonic crystal silicon nanocavity.

Opt Express 2015 Feb;23(4):3951-9

We have precisely measured the Raman shift of photonic crystal silicon heterostructure nanocavities for Raman laser applications. We utilized a near-infrared excitation laser of wavelength 1.42 μm in order to avoid local sample heating and exploited two high-Q nanocavity modes to calibrate the Raman frequency. The measured Raman shift was 15.606 THz (520.71 cm(-1)) with a small uncertainty of 1.0 × 10(-3) THz. In addition, we investigated the compressive stress generated in a photonic crystal slab in which a ~5.1 × 10(-3) THz blue shift of the Raman peak and a slight warpage of the slab were observed. We also demonstrated that the stress could be eliminated by using a cantilever structure.
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http://dx.doi.org/10.1364/OE.23.003951DOI Listing
February 2015

Ultra-compact 32-channel drop filter with 100 GHz spacing.

Opt Express 2014 Feb;22(4):4692-8

We demonstrated 32-channel drop filters with 100 GHz spacing consisting of arrayed nanocavities and a waveguide in a photonic crystal silicon slab. Changing the lattice constant of the nanocavities on the subnanometer scale successfully controlled the drop wavelengths at 100 GHz spacing in the wavelength range between 1510 and 1550 nm. The device size was as small as 15 μm × 270 μm, and the variation in drop wavelengths was less than 0.3 nm in terms of standard deviation. We also present a movie showing the operation of the drop filter, demonstrating that the arrayed nanocavities have the potential for developing ultracompact 100 GHz spaced filters in a dense wavelength division multiplexing system.
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http://dx.doi.org/10.1364/OE.22.004692DOI Listing
February 2014

Influence of the pore generator on the evolution of the mechanical properties and the porosity and interconnectivity of a calcium phosphate cement.

Acta Biomater 2012 Jan 18;8(1):404-14. Epub 2011 Aug 18.

Department of Biomaterials, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands.

Porosity and interconnectivity are important properties of calcium phosphate cements (CPCs) and bone-replacement materials. Porosity of CPCs can be achieved by adding polymeric biodegradable pore-generating particles (porogens), which can add porosity to the CPC and can also be used as a drug-delivery system. Porosity affects the mechanical properties of CPCs, and hence is of relevance for clinical application of these cements. The current study focused on the effect of combinations of polymeric mesoporous porogens on the properties of a CPC, such as specific surface area, porosity and interconnectivity and the development of mechanical properties. CPC powder was mixed with different amounts of PLGA porogens of various molecular weights and porogen sizes. The major factors affecting the properties of the CPC were related to the amount of porogen loaded and the porogen size; the molecular weight did not show a significant effect per se. A minimal porogen size of 40 μm in 30 wt.% seems to produce a CPC with mechanical properties, porosity and interconnectivity suitable for clinical applications. The properties studied here, and induced by the porogen and CPC, can be used as a guide to evoke a specific host-response to maintain CPC integrity and to generate an explicit bone ingrowth.
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http://dx.doi.org/10.1016/j.actbio.2011.08.010DOI Listing
January 2012

Comparative analysis of copy number variation detection methods and database construction.

BMC Genet 2011 Mar 7;12:29. Epub 2011 Mar 7.

Central Research Laboratory, Hitachi Ltd., Tokyo, Japan.

Background: Array-based detection of copy number variations (CNVs) is widely used for identifying disease-specific genetic variations. However, the accuracy of CNV detection is not sufficient and results differ depending on the detection programs used and their parameters. In this study, we evaluated five widely used CNV detection programs, Birdsuite (mainly consisting of the Birdseye and Canary modules), Birdseye (part of Birdsuite), PennCNV, CGHseg, and DNAcopy from the viewpoint of performance on the Affymetrix platform using HapMap data and other experimental data. Furthermore, we identified CNVs of 180 healthy Japanese individuals using parameters that showed the best performance in the HapMap data and investigated their characteristics.

Results: The results indicate that Hidden Markov model-based programs PennCNV and Birdseye (part of Birdsuite), or Birdsuite show better detection performance than other programs when the high reproducibility rates of the same individuals and the low Mendelian inconsistencies are considered. Furthermore, when rates of overlap with other experimental results were taken into account, Birdsuite showed the best performance from the view point of sensitivity but was expected to include many false negatives and some false positives. The results of 180 healthy Japanese demonstrate that the ratio containing repeat sequences, not only segmental repeats but also long interspersed nuclear element (LINE) sequences both in the start and end regions of the CNVs, is higher in CNVs that are commonly detected among multiple individuals than that in randomly selected regions, and the conservation score based on primates is lower in these regions than in randomly selected regions. Similar tendencies were observed in HapMap data and other experimental data.

Conclusions: Our results suggest that not only segmental repeats but also interspersed repeats, especially LINE sequences, are deeply involved in CNVs, particularly in common CNV formations.The detected CNVs are stored in the CNV repository database newly constructed by the "Japanese integrated database project" for sharing data among researchers. http://gwas.lifesciencedb.jp/cgi-bin/cnvdb/cnv_top.cgi.
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http://dx.doi.org/10.1186/1471-2156-12-29DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3058066PMC
March 2011

Screening for tyrosinase inhibitors among extracts of seashore plants and identification of potent inhibitors from Garcinia subelliptica.

Biosci Biotechnol Biochem 2005 Jan;69(1):197-201

Faculty of Integrated Arts and Sciences, University of Tokushima, Tokushima, Japan.

The tyrosinase inhibitory activity of methanol extracts of the leaves of 39 plant species growing on the seashore of Iriomote island (Okinawa, Japan) was investigated. The extracts of Hibiscus tiliaceus, Carex pumila, and Garcinia subelliptica showed potent activity among them. The inhibitors in the extract of Garcinia subelliptica were purified by assay-guided fractionation to give two biflavonoids. These were known compounds (2R,3S-5,7,4',5'',7'',3''',4'''-heptahydroxy flavanone[3-8''] flavone and 5,7,4',5'',7'',3''',4'''-heptahydroxy[3-8''] biflavanone), although their strong inhibitory activity toward tyrosinase is revealed for the first time in this work. One of these biflavonoids (2R,3S-5,7,4',5'',7'',3''',4'''-heptahydroxy flavanone[3-8''] flavone) showed much stronger activity (IC50 2.5 microM) than that of kojic acid (IC50 9.1 microM) when L-tyrosine was used as the substrate.
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http://dx.doi.org/10.1271/bbb.69.197DOI Listing
January 2005
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