Flavonoids of cocoa inhibit recombinant human 5-lipoxygenase

(-)-Epicatechin and its related oligomers, the procyanidins, are present in sizable amounts in some cocoas and chocolates. Intake of flavonoid-rich chocolate in humans has been reported to increase the plasma level of (-)-epicatechin and concomitantly to significantly decrease the plasma level of proinflammatory cysteinyl leukotrienes. Because leukotrienes are formed via the 5-lipoxygenase pathway of arachidonic acid metabolism, we examined whether 5-lipoxygenase is a possible target for the flavonoids of cocoa. Recombinant human 5-lipoxygenase was reacted with arachidonic acid and yielded a mixture of mainly 5-hydroperoxy-6E,8Z, 11Z,14Z-eicosatetraenoic acid (5-HpETE) and hydrolysis products of 5,6-leukotriene A(4) (LTA(4)). The formation of these products was significantly inhibited by (-)-epicatechin in a dose-dependent manner with 50% inhibitory concentrations (IC(50)) of 22 and 50 micromol/L, respectively. Among the procyanidin fractions isolated from the seeds of Theobroma cacao, only the dimer fraction and, to a lesser extent, the trimer through pentamer fractions exhibited comparable effects, whereas the larger procyanidins (hexamer through nonamer) were almost inactive. We conclude that (-)-epicatechin and its low-molecular procyanidins inhibit both dioxygenase and LTA(4) synthase activities of human 5-lipoxygenase and that this action may contribute to a putative anti-inflammatory effect of cocoa products.     

Inhibition of 15-lipoxygenases by flavonoids: structure-activity relations and mode of action

We have recently reported that flavonoids of cocoa inhibit the mammalian 15-lipoxygenase-1-a catalyst of enzymatic lipid peroxidation. To elucidate the structure-activity relationship of the inhibitory effect, we investigated the effects of 18 selected flavonoids of variable structure on pure rabbit reticulocyte and soybean 15-lipoxygenases using linoleic acid as substrate. Moreover, the inhibition by quercetin was studied in detail to gain insight into the mode of action. Quercetin was found to modulate the time-course of the reaction of both lipoxygenases by three distinct effects: (i) prolongation of the lag period, (ii) rapid decrease in the initial rate after the lag phase was overcome, (iii) time-dependent inactivation of the enzyme during reaction but not in the absence of substrate. A comparison of the IC(50) for the rapid inhibition of rabbit reticulocyte 15-lipoxygenase-1 revealed that (i) the presence of a hydroxyl group in the flavonoid molecule is not essential, (ii) a catechol arrangement reinforces the inhibitory effect, (iii) in the presence of a catechol arrangement the inhibitory potency inversely correlates with the number of hydroxyl groups, (iv) a 2,3-double bond in the C ring strengthens the inhibitory effect. The flavone luteolin turned out to be the most potent inhibitor of the mammalian enzyme with an IC(50) of 0.6 microM followed by baicalein (1 microM) and fisetin (1.5 microM).     

Treatment of patients with arthrosis of hip or knee with an aqueous extract of devil's claw (Harpagophytum procumbens DC.)

Preparations made from the secondary tubers of Devil's claw (Harpagophytum procumbens) are successfully used in patients with rheumatic diseases (arthrosis and low back pain). In order to add data on the efficacy and long-term safety of an aqueous extract (Doloteffin; 2400 mg extract daily, corresponding to 50 mg harpagoside), which has been tested successfully in patients with low back pain, an uncontrolled multicentre drug surveillance study for about 12 weeks was conducted in 75 patients with arthrosis of the hip or knee. To standardize the assessment of treatment effects, the Western Ontario and McMaster Universities (WOMAC) osteoarthritis index (10 point scale) as well as the 10 cm VAS pain scale were used. The results of the study revealed a strong reduction of pain and the symptoms of osteoarthritis. There was a relevant improvement of each WOMAC subscale as well as of the total WOMAC index: 23.8% for the pain subscale, 22.2% for the stiffness subscale and 23.1% for the physical function subscale. The WOMAC total score was reduced by 22.9%. VAS pain scores were decreased by 25.8% for actual pain, 25.2% for average pain, 22.6% for worst pain and 24.5% for the total pain score. The physicians reported a continuous improvement in typical clinical findings such as 45.5% for pain on palpation, 35% for limitation of mobility and 25.4% for joint crepitus. Only two cases of possible adverse drug reactions were reported (dyspeptic complaints and a sensation of fullness). Although this was an open clinical study, the results suggest that this Devil's claw extract has a clinically beneficial effect in the treatment of arthrosis of the hip or knee.     

Prospective comparison of 18F-FDG PET with conventional imaging modalities (CT, MRI, US) in lymph node staging of head and neck cancer

The aims of this study were to investigate the detection of cervical lymph node metastases of head and neck cancer by positron emission tomographic (PET) imaging with fluorine-18 fluorodeoxyglucose (FDG) and to perform a prospective comparison with computed tomography (CT), magnetic resonance imaging (MRI), sonographic and histopathological findings. Sixty patients with histologically proven squamous cell carcinoma were studied by PET imaging before surgery. Preoperative endoscopy (including biopsy), CT, MRI and sonography of the cervical region were performed in all patients within 2 weeks preceding ¹⁸F-FDG whole-body PET. FDG PET images were analysed visually and quantitatively for objective assessment of regional tracer uptake. Histopathology of the resected neck specimens revealed a total of 1284 lymph nodes, 117 of which showed metastatic involvement. Based on histopathological findings, FDG PET correctly identified lymph node metastases with a sensitivity of 90% and a specificity of 94% (P<10^–6). CT and MRI visualized histologically proven lymph node metastases with a sensitivity of 82% (specificity 85%) and 80% (specificity 79%), respectively (P<10^–6). Sonography revealed a sensitivity of 72% (P<10^–6). The comparison of ¹⁸F-FDG PET with conventional imaging modalities demonstrated statistically significant correlations (PET vs CT, P = 0.017; PET vs MRI, P = 0.012; PET vs sonography, P = 0.0001). Quantitative analysis of FDG uptake in lymph node metastases using body weight-based standardized uptake values (SUV_BW) showed no significant correlation between FDG uptake (3.7±2.0) and histological grading of tumour-involved lymph nodes (P = 0.9). Interestingly, benign lymph nodes had increased FDG uptake as a result of inflammatory reactions (SUV_BW-range: 2–15.8). This prospective, histopathologically controlled study confirms FDG PET as the procedure with the highest sensitivity and specificity for detecting lymph node metastases of head and neck cancer and has become a routine method in our University Medical Center. Furthermore, the optimal diagnostic modality may be a fusion image showing the increased metabolism of the tumour and the anatomical localization. Received 17 February and in revised form 12 June 1998     

Premature luteinization of follicles during ovarian stimulation for in-vitro fertilization

The structure and growth of developing follicles was monitored using vaginal ultrasound scanning in an outpatient programme of in-vitro fertilization (IVF) and embryo transfer (ET). Patients received either human menopausal gonadotrophin (HMG) alone or clomiphene citrate (CC) + HMG for controlled ovarian stimulation. Ultrasound data were compared with pre-ovulatory oestradiol (E2), luteinizing hormone (LH) and progesterone (P) levels. Hormonal parameters and results were classified according to the main indications of IVF-ET treatment. Twenty-one of the 271 patients in the study showed ultrasonic evidence of premature luteinization (PL) of follicles, thickening of the follicular wall and the appearance of irregular echogenic structures in the follicle. PL was preceded in eight cases by an indisputable LH surge and subsequent P elevation. In the remaining 13 cases PL occurred either due to an abortive LH surge not exceeding by 3-fold the baseline values or as a result of HMG administration. Special attention was paid to the P pattern prior to and after human chorionic gonadotrophin (HCG) administration. PL cycles demonstrated significantly (P less than 0.05) higher P levels before HCG administration and at the time of oocyte retrieval as well. Because implantation was not achieved in these cases, the cancellation of PL cycles is recommended. Vaginal ultrasound scanning seems to be helpful in the evaluation of minor changes in the follicular structure, correlating frequently with hormonal findings.     

Treatment of Mild Gastrointestinal Disorders with a Herbal Combination: Results of a Non‐interventional Study with Gastritol® Liquid

A combination of extracts from chamomile, silverweed, licorice, angelica, blessed thistle and wormwood, Gastritol^® Liquid, is registered for the use of indigestion and gastrointestinal spasmodic complaints. To gain data on the experience in practice, a non‐interventional open study was conducted in ambulatory patients including diabetics which were treated for 2 weeks. The efficacy of treatment was assessed by medical examination and evaluation of typical symptoms by patients. A total of 149 patients was enrolled, 90 without and 59 with diabetes. The treatment led to relevant improvements in all symptoms in both study groups. The most notable improvements were seen for the symptoms vomiting (?66.7%; diabetics: ?63.9%) and retching (?52.2%; diabetics: ?53.6%). An overall improvement was rated by about 90% in both study groups. In seven patients adverse events had been reported (5 times temporary nausea after intake, one time gastric spasm and one time oral burning sensation), all of them of mild nature. The global tolerability was assessed as good or very good in more than 80% by practitioners and patients. Under the conditions of this open study method Gastritol^® Liquid had been shown to be safe and effective in the treatment of mild gastrointestinal disorders, including diabetic patients. Copyright © 2015 John Wiley & Sons, Ltd.     

Periosteum‐derived mesenchymal progenitor cells in engineered implants promote fracture healing in a critical‐size defect rat model

An attractive alternative to bone autografts is the use of autologous mesenchymal progenitor cells (MSCs) in combination with biomaterials. We compared the therapeutic potential of different sources of mesenchymal stem cells in combination with biomaterials in a bone nonunion model. A critical‐size defect was created in Sprague–Dawley rats. Animals were divided into six groups, depending on the treatment to be applied: bone defect was left empty (CTL); treated with live bone allograft (LBA); hrBMP‐2 in collagen scaffold (CS^BMP2); acellular polycaprolactone scaffold (PCL group); PCL scaffold containing periosteum‐derived MSCs (PCL^PMSCs) and PCL containing bone marrow‐derived MSCs (PCL^BMSCs). To facilitate cell tracking, both MSCs and bone graft were isolated from green fluorescent protein (GFP)‐transgenic rats. CTL group did not show any signs of healing during the radiological follow‐up (n = 6). In the LBA group, all the animals showed bone bridging (n = 6) whereas in the CS^BMP2 group, four out of six animals demonstrated healing. In PCL and PCL^PMSCs groups, a reduced number of animals showed radiological healing, whereas no healing was detected in the PCL^BMSCs group. Using microcomputed tomography, the bone volume filling the defect was quantified, showing significant new bone formation in the LBA, CS^BMP2, and PCL^PMSCs groups when compared with the CTL group. At 10 weeks, GFP positive cells were detected only in the LBA group and restricted to the outer cortical bone in close contact with the periosteum. Tracking of cellular implants demonstrated significant survival of the PMSCs when compared with BMSCs. In conclusion, PMSCs improve bone regeneration being suitable for mimetic autograft design.