Search tips
Search criteria

Results 1-9 (9)

Clipboard (0)

Select a Filter Below

Year of Publication
Document Types
1.  Resveratrol derivatives as promising chemopreventive agents with improved potency and selectivity 
Molecular nutrition & food research  2011;55(8):1249-1265.
Despite scores of investigations, the actual impact of resveratrol (3,5,4′-trihydroxy-trans-stilbene) on human health, as a dietary component or supplement, remains moot. This is due to many factors, such as relatively low potency, pleiotropic mechanisms, and rapid metabolism. Nonetheless, as a promiscuous molecule that interacts with numerous targets, resveratrol can be viewed as a scaffold for designing structural relatives potentially capable of mediating more intense responses with greater mechanistic stringency. We currently report the synthesis and biological evaluation of 92 stilbene analogs. The compounds were tested with in vitro assays for activation of quinone reductase 1, inhibition of QR2, nitric oxide production, aromatase, NFκB, TPA-induced ornithine decarboxylase, or cyclooxygenase-1 and -2, quenching of 2,2-diphenyl-1-picrylhydrazyl free radical, interaction with estrogen receptors, and as antiproliferative agents. Several compounds were found to mediate responses with much greater potency than resveratrol; some mediated pleiotropic responses, as is the case with the parent molecule, but others were highly specific or totally inactive. When administered to rats, higher serum concentrations and greater stability was demonstrated with prototype lead molecules. Due to structural simplicity, facile syntheses are available for large-scale production. These data support the promise of more advanced development of novel resveratrol derivatives as drug entities.
PMCID: PMC4135049  PMID: 21714126
resveratrol; chemoprevention; pleiotropic effect; Caco-2 cells; absorption; mass spectrometry
2.  Transverse Process and Needles of Medial Branch Block to Facet Joint as Landmarks for Ultrasound-Guided Selective Nerve Root Block 
Clinics in Orthopedic Surgery  2013;5(1):44-48.
Selective lumbar nerve root block (SNRB) is generally accepted as an effective treatment method for back pain with sciatica. However, it requires devices producing radioactive materials such as C-arm fluoroscopy. This study evaluated the usefulness of the longitudinal view of transverse process and needles for medial branch block as landmarks under ultrasonography.
We performed selective nerve root block for 96 nerve roots in 61 patients under the guidance of ultrasound. A curved probe was used to identify the facet joints and transverse processes. Identifying the lumbar nerve roots under the skin surface and ultrasound landmarks, the cephalad and caudal medial branch blocks were undertaken under the transverse view of sonogram first. A needle for nerve root block was inserted between the two transverse processes under longitudinal view, while estimating the depth with the needle for medial branch block. We then injected 1.0 mL of contrast medium and checked the distribution of the nerve root with C-arm fluoroscopy to evaluate the accuracy. The visual analog scale (VAS) was used to access the clinical results.
Seven SNRBs were performed for the L2 nerve root, 15 for L3, 49 for L4, and 25 for L5, respectively. Eighty-six SNRBs (89.5%) showed successful positioning of the needles. We failed in the following cases: 1 case for the L2 nerve root; 2 for L3; 3 for L4; and 4 for L5. The failed needles were positioned at wrong leveled segments in 4 cases and inappropriate place in 6 cases. VAS was improved from 7.6 ± 0.6 to 3.5 ± 1.3 after the procedure.
For SNRB in lumbar spine, the transverse processes under longitudinal view as the ultrasound landmark and the needles of medial branch block to the facet joint can be a promising guidance.
PMCID: PMC3582870  PMID: 23467334
Lumbar spine; Spinal injections; Ultrasound
3.  The Validation of Ultrasound-Guided Lumbar Facet Nerve Blocks as Confirmed by Fluoroscopy 
Asian Spine Journal  2012;6(3):163-167.
Study Design
This is a prospective study.
To develop a methodological approach for conducting ultrasound-guided lumbar facet nerve block by defining essential ultrasound-guided landmarks in order to assess the feasibility of this method.
Overview of Literature
The current role of ultrasound guidance for musculoskeletal intervention treatments has been reported upon in previous literature.
Ultrasound-guided facet nerve block was done in 95 segments for 50 patients with chronic back pain by facet arthropathy. After the surface landmarks of the spinous process and iliac crest line were confirmed, longitudinal facet views were obtained by a curved array transducer to identify the different spinal segments. The spinous process and facet joint with transverse process were delineated by transverse sonograms at each level and the target point for the block was defined as lying on the upper edge of the transverse process. The needle was inserted toward the target point. After a contrast injection, the placement of the needle and contrast was checked by fluoroscopy.
Eighty-seven segments (91.6%) could be guided successfully to the right facet nerve block by using ultrasound. After fluoroscopic control, 8 needles had to be corrected because of problems with other segments (3 cases) and lamina placements (5 cases). For the 42 patients who underwent successful block by ultrasound, however, the mean visual analogue score for back pain was improved from 6.2 ± 0.9 before the block to 4.0 ± 1.0 after the block (p = 0.001).
Ultrasound-guided longitudinal facet view and the surface landmarks of the spinous process and iliac crest line seems to be a promising guidance technique for the lumbar facet nerve block technique.
PMCID: PMC3429606  PMID: 22977695
Lumbosacral region; Nerve block; Ultrasonography
4.  Bioactive Compounds from the Fern Lepisorus contortus 
Journal of natural products  2011;74(2):129-136.
Phytochemical investigation of the whole plant of Lepisorus contortus (Christ) Ching led to the isolation of five new phenylethanoid glycosides (1–5), each containing a caffeoyl group, a new flavonoid glycoside (10), as well as 14 known compounds (6–9 and 11–15, syringic acid, vanillic acid, phloretic acid, diplopterol, and β-sitosterol). This is the first report of phenylethanoid glycosides from the family Polypodiaceae. Compounds 1–15 were evaluated for their cancer chemopreventive potential based on their ability to inhibit tumor necrosis factor alpha (TNF-α)-induced NF-κB activity, nitric oxide (NO) production, aromatase, quinone reductase 2 (QR-2), and COX-1/-2 activities. Quercetin-3-O-β-D-glucoside (15) demonstrated inhibition against QR2 with an IC50 value of 6.7 µM, which confirmed kaempferol/quercetin glycosides as the active compounds to inhibit QR2. The compound also demonstrated NF-κB activity with an IC50 value of 33.6 µM. In addition, compounds 1, 2, 4 and 6 showed aromatase activity with IC50 values of 30.7, 32.3, 26.8, and 35.3 µM, respectively.
PMCID: PMC3069126  PMID: 21261296
5.  Screening natural products for inhibitors of quinone reductase-2 using ultrafiltration LC-MS 
Analytical chemistry  2010;83(3):1048-1052.
Inhibitors of quinone reductase-2 (NQO2; QR-2) can have anti-malarial activity and anti-tumor activities or can function as chemoprevention agents by preventing the metabolic activation of toxic quinones such as menadione. To expedite the search for new natural product inhibitors of QR-2, we developed a screening assay based on ultrafiltration liquid chromatography-mass spectrometry that is compatible with complex samples such as bacterial or botanical extracts. Human QR-2 was prepared recombinantly, and the known QR-2 inhibitor, resveratrol, was used as a positive control and as a competitive ligand to eliminate false positives. Ultrafiltration LC-MS screening of extracts of marine sediment bacteria resulted in the discovery of tetrangulol methyl ether as an inhibitor of QR-2. When applied to the screening of hop extracts from the botanical, Humulus lupulus L., xanthohumol and xanthohumol D were identified as ligands of QR-2. Inhibition of QR-2 by these ligands was confirmed using a functional enzyme assay. Furthermore, binding of xanthohumol and xanthohumol D to the active site of QR-2 were confirmed using X-ray crystallography. Ultrafiltration LC-MS was shown to be a useful assay for the discovery of inhibitors of QR-2 in complex matrices such as extracts of bacteria and botanicals.
PMCID: PMC3034444  PMID: 21192729
6.  Discovery of cyclooxygenase inhibitors from medicinal plants used to treat inflammation 
Eleven authenticated botanicals used in the traditional Chinese medicine Huo-Luo-Xiao-Ling Dan were screened for ligands to cyclooxygenase (COX) using pulsed ultrafiltration liquid chromatography-mass spectrometry, and a mass spectrometry-based enzyme assay was used to determine the concentration of each of 17 ligands that inhibited COX-1 or COX-2 by 50% (IC50). Acetyl-11-keto-β-boswellic -boswellic acid, acid, acetyl-α-boswellic acid, acetyl-β-boswellic acid, and betulinic acid were COX-1 selective inhibitors with IC50 values of approximately 10 μM. Senkyunolide O and cryptotanshinone were COX-2 selective inhibitors with IC50 values of 5 and 22 μM, respectively. Roburic acid and phenethyl-trans-ferulate inhibited COX-1 and COX-2 equally. COX inhibition and the IC50 values of most of these natural product ligands have not been reported previously.
PMCID: PMC2860736  PMID: 20188172
Cyclooxygenase; COX-2; drug discovery; botanical dietary supplements; senkyunolide O; cryptotanshinone
7.  Isolation and evaluation of kaempferol glycosides from the fern Neocheiropteris palmatopedata 
Phytochemistry  2010;71(5-6):641-647.
Three new kaempferol glycosides, named palmatosides A (1), B (2) and C (3), together with three known kaempferol glycosides, multiflorins A (4) and B (5), and afzelin (6), were isolated from the roots of the fern Neocheiropteris palmatopedata. Palmatosides A (1) and B (2) were determined to be novel kaempferol glycosides, each possessing an unusual sugar moiety containing a 4, 4-dimethyl-3-oxo-butoxy substituent group. The isolated compounds were evaluated for their cancer chemopreventive potential based on their ability to inhibit tumor necrosis factor alpha (TNF-α)-induced NF-κB activity, nitric oxide (NO) production, aromatase, quinone reductase 2 (QR-2) and COX-1/-2 activities. Palmatosides B (2) and C (3) inhibited TNF-α-induced NF-κB activity with IC50 values of 15.7 and 24.1 μM, respectively; multiflorin A (4) inhibited aromatase enzyme with an IC50 value of 15.5 μM; afzelin (6) showed 68.3% inhibition against QR2 at a concentration of 11.5 μg/ml; palmatoside A (1) showed 52 % inhibition against COX-1 enzyme at a concentration of 10 μg/ml; and multiflorin B (5) showed 52 % inhibition against nitric oxide production at a concentration of 20 μg/ml. In addition, compounds 3-6 were shown to bind QR2 enzyme using LC-MS ultrafiltration binding assay.
PMCID: PMC2866494  PMID: 20100622
Neocheiropteris palmatopedata; Polypodiaceae; flavone; kaempferol glycosides; palmatosides; cancer chemoprevention; NF-κB; NO; QR-2; aromatase; COX-1; COX-2
8.  Adjacent Segment Instability after Treatment with a Graf Ligament at Minimum 8 Years’ Followup 
Although there has been some enthusiasm over the early clinical results obtained using the Graf ligament, associated mid- to long-term results are controversial. We retrospectively reviewed 43 patients (67 segments) treated with the Graf ligament for degenerative lumbar stenosis. The minimum followup was 8 years (mean, 10 years; range, 8–14 years). At last followup, we observed angular instability in 19 of the 67 segments (28%) and translational instability in five (7%). The disc height decreased from postoperatively (mean 93% of the preoperative disc) to the final followup (mean 82%). Of the 43 patients, 18 (42%) had adjacent segmental instability at the upper segment, including angular instability in 11 patients, translational instability in four patients, and both in three patients. The adjacent segment instability at the lower segment revealed 13 patients (30%) with angular instability. The data suggest the anticipated mechanical effects of the Graf ligament can be altered by degeneration of the disc and facet joints at instrumented segments and the adjacent segment can be affected, perhaps as a result of abnormal load transmission.
Level of Evidence: Level IV, therapeutic study. See the Guidelines for Authors for a complete description of levels of evidence.
PMCID: PMC2690771  PMID: 19452237
9.  Development of a screening assay for ligands to the estrogen receptor based on magnetic microparticles and LC-MS 
A high throughput screening assay for the identification of ligands to pharmacologically significant receptors was developed based on magnetic particles containing immobilized receptors followed by liquid chromatography—mass spectrometry (LC-MS). This assay is suitable for the screening of complex mixtures such as botanical extracts. For proof-of-principle, estrogen receptor-α (ER-α) and ER-β were immobilized on magnetic particles functionalized with aldehyde or carboxylic acid groups. Alternatively, biotinylated ER was immobilized onto streptavidin-derivatized magnetic particles. The ER that was immobilized using the streptavidin-biotin chemistry showed higher activity than that immobilized on aldehyde or carboxylic acid functionalized magnetic particles. Immobilized ER was incubated with extracts of Trifolium pratense L. (red clover) or Humulus lupulus L. (hops). As a control for non-specific binding, each botanical extract was incubated with magnetic particles containing no ER. After magnetic separation of the particles containing bound ligands from the unbound components in the extract, the particles were washed, ligands were released using methanol, and then the ligands were identified using LC-MS. The estrogens genistein and daidzein were identified in the red clover extract, and the estrogen 8-prenylnaringenin was identified in the hop extract. These screening results are consistent with those obtained using previous screening approaches.
PMCID: PMC2736128  PMID: 18220538

Results 1-9 (9)