Separation and Identification of Antioxidants and Aldose Reductase Inhibitors in Lepechinia meyenii (Walp.) Epling.

We previously reported that Lepechinia meyenii (Walp.) Epling has antioxidant and aldose reductase (AR) inhibitory activities. In this study, L. meyenii was extracted in a 50% MeOH and CH2Cl2/MeOH system. The active extracts of MeOH and 50% MeOH were subjected to fractionation, followed by separation using high-speed counter-current chromatography (HSCCC) and preparative HPLC. Separation and identification revealed the presence of caffeic acid, hesperidin, rosmarinic acid, diosmin, methyl rosmarinate, diosmetin, and butyl rosmarinate. Of these, rosmarinic acid, methyl rosmarinate, and butyl rosmarinate possessed remarkable antioxidant and AR inhibitory activities. The other compounds were less active. In particular, rosmarinic acid is the key contributor to the antioxidant and AR inhibitory activities of L. meyenii; it is rich in the MeOH extract (333.84 mg/g) and 50% MeOH extract (135.41 mg/g) of L. meyenii and is especially abundant in the EtOAc and n-BuOH fractions (373.71-804.07 mg/g) of the MeOH and 50% MeOH extracts. The results clarified the basis of antioxidant and AR inhibitory activity of L. meyenii, adding scientific evidence supporting its traditional use as an anti-diabetic herbal medicine. The HSCCC separation method established in this study can be used for the preparative separation of rosmarinic acid from natural products.

Cytokine Response to Diet and Exercise Affects Atheromatous Matrix Metalloproteinase-2/9 Activity in Mice.

BACKGROUND: The aim of this study is to identify the principal circulating factors that modulate atheromatous matrix metalloproteinase (MMP) activity in response to diet and exercise.Methods and Results:Apolipoprotein-E knock-out (ApoE-/-) mice (n=56) with pre-existing plaque, fed either a Western diet (WD) or normal diet (ND), underwent either 10 weeks of treadmill exercise or had no treatment. Atheromatous MMP activity was visualized using molecular imaging with a MMP-2/9 activatable near-infrared fluorescent (NIRF) probe. Exercise did not significantly reduce body weight, visceral fat, and plaque size in either WD-fed animals or ND-fed animals. However, atheromatous MMP-activity was different; ND animals that did or did not exercise had similarly low MMP activities, WD animals that did not exercise had high MMP activity, and WD animals that did exercise had reduced levels of MMP activity, close to the levels of ND animals. Factor analysis and path analysis showed that soluble vascular cell adhesion molecule (sVCAM)-1 was directly positively correlated to atheromatous MMP activity. Adiponectin was indirectly negatively related to atheromatous MMP activity by way of sVCAM-1. Resistin was indirectly positively related to atheromatous MMP activity by way of sVCAM-1. Visceral fat amount was indirectly positively associated with atheromatous MMP activity, by way of adiponectin reduction and resistin elevation. MMP-2/9 imaging of additional mice (n=18) supported the diet/exercise-related anti-atherosclerotic roles for sVCAM-1. CONCLUSIONS: Diet and exercise affect atheromatous MMP activity by modulating the systemic inflammatory milieu, with sVCAM-1, resistin, and adiponectin closely interacting with each other and with visceral fat.

Green-channel autofluorescence imaging: A novel and sensitive technique to delineate infarcts.

BACKGROUND: We have found that infarcted brain regions exhibit green channel autofluorescence (GCAF). Here, we compare ex vivo GCAF-imaging with 2,3,5-triphenylteterazolium chloride (TTC)-staining. NEW METHOD: C57BL/6 mice (n=120) underwent GCAF-imaging after transient or permanent middle cerebral artery occlusion (tMCAO or pMCAO). COMPARISON WITH EXISTING METHODS: TTC-staining may not reflect subtle ischemic injury. TTC-stained tissues, when reused, are prone to processing artifacts related to prior TTC-staining. GCAF imaging requires little experimental manipulation of animals and brain tissues, and allows for more consistent measurements of infarct volume and reliable reuse of the fresh unstained tissues. RESULTS: Lesion volumes measured at 24-h after 1-h tMCAO by using GCAF-images were similar to those using TTC-staining: 87.6±13.6mm3 vs. 83.8±12.8mm3 in 1mm-thick sections (n=9 mice, 10 slices/mouse, p=0.88; Pearson's r=0.91, p<0.001) and 75.1±7.6mm3 vs. 73.6±6.7mm3 in 2 mm-thick sections (n=9 mice, 5 slices/mouse, p=0.99; Pearson's r=0.87, p<0.001), respectively. In serial ex vivo imaging performed at 1, 2, 3, 6, 12, and 24-h after tMCAO, GCAF-imaging correlated well with TTC-staining at all time-points. In the pMCAO model however, the correlation was strong at later time-points (6-24-h); but at time points up to 3-h, GCAF-imaging was more sensitive than TTC-staining to detect ischemic areas, as verified by histology, where ischemic damage was observed in the GCAF-positive areas of the cerebral cortex and striatum, even in the face of normal TTC-staining. CONCLUSION: GCAF-imaging is a reliable alternative to TTC-staining in the qualitative and quantitative assessments of focal brain ischemia, and more sensitive for detecting early ischemic damage in pMCAO.

A new micro-computed tomography-based high-resolution blood-brain barrier imaging technique to study ischemic stroke.

BACKGROUND AND PURPOSE: Micro-computed tomography (mCT) offers high-resolution images, but it suffers from low contrast sensitivity and poor soft tissue contrast. We introduce a new mCT imaging technique with improved sensitivity for the dynamic spatial and temporal characterization of poststroke blood-brain barrier (BBB) dysfunction in small animals in vivo. METHODS: Transient middle cerebral artery occlusion was induced for 1 hour in 10- to 12-week-old C57BL/6 mice (n=35). At 4, 24, and 48 hours after ischemic stroke, serial in vivo mCT imaging was performed 5 minutes after intravenous infusion (n=3) or intracarotid infusion of iopromide (240 µL) for 5 minutes (n=32). After intravenous injection of 2% Evans blue, we performed ex vivo near-infrared fluorescent imaging of parenchymal Evans blue leakage, visual assessment of poststroke parenchymal hematoma, triphenyltetrazolium chloride staining of the brain tissue, and quantitative mapping of stroke-related brain lesions. RESULTS: Infarct-related BBB dysfunction could be demonstrated with intra-arterial but not with intravenous infusion of iopromide. Iopromide leakage across the dysfunctional BBB showed a monophasic (not biphasic) course for 48 hours after ischemic insult in both the parenchymal hematoma (n=5) and the non-parenchymal hematoma (n=24) groups, with relatively severe leakiness and greater hemispheric midline shift in animals with hemorrhage. Parenchymal staining on in vivo mCT overlapped with ex vivo fluorescent staining because of Evans blue. Multivariable analyses showed that midline shift and the amount of iopromide leakage at each of the 3 time points predicted the final infarct size at 48 hours. CONCLUSIONS: The new mCT BBB imaging technique, based on the intra-arterial infusion of clinically available iopromide, allows serial quantitative visualization of poststroke BBB dysfunction in mice, with high resolution and in a sensitive manner.

Hypoxia antagonizes glucose deprivation on interleukin 6 expression in an Akt dependent, but HIF-1/2α independent manner.

Although both glucose deprivation and hypoxia have been reported to promote cascades of biological alterations that lead to induction of inflammatory mediators, we hypothesized that glucose deprivation and hypoxia might show neutral, synergistic or antagonistic effects to each other on gene expression of inflammatory mediators depending on the regulatory components in their promoters. Gene expression of interleukin 6 (IL-6) was analyzed by real-time PCR, ELISA, or Western blot. Effects of glucose deprivation and/or hypoxia on activation of signaling pathways were analyzed by time-dependent phosphorylation patterns of signaling molecules. We demonstrate that hypoxia antagonized the effects of glucose deprivation on induction of IL-6 gene expression in microglia, macrophages, and monocytes. Hypoxia also antagonized thapsigargin-induced IL-6 gene expression. Hypoxia enhanced phosphorylation of Akt, and inhibition of Akt was able to reverse the effects of hypoxia on IL-6 gene expression. However, inhibition of HIF-1/2α did not reverse the effects of hypoxia on IL-6 gene expression. In addition, phosphorylation of p38, but not JNK, was responsible for the effects of glucose deprivation on IL-6 gene expression.

Inhibitory effects of furoquinoline alkaloids from Melicope confusa and Dictamnus albus against human phosphodiesterase 5 (hPDE5A) in vitro.

Eight furoquinoline alkaloids were purified from two plants belonging to the Rutaceae family. Kokusaginine, skimmianine, evolitrine, and confusameline were purified from Melicope confusa, and haplopine, robustine, dictamine, and gamma-fagarine from Dictamnus albus. In this study, the eight furoquinoline alkaloids were examined for inhibitory potency against human phosphodiesterase 5 (hPDE5A) in vitro. DNA encoding the catalytic domain of human PDE5A was amplified from the mRNA of T24 cells by RT-PCR and was fused to GST in an expression vector. GST-tagged PDE5A was then purified by glutathione affinity chromatography and used in inhibition assays. Of the eight alkaloids, gamma-fagarine was the most potent inhibitor of PDE5A, and its single methoxy group at the C-8 position was shown to be critical for inhibitory activity. These results clearly illustrate the relationship between PDE5A inhibition and the methoxy group position in furoquinoline alkaloids.

TERT mRNA expression is up-regulated in MCF-7 cells and a mouse mammary organ culture (MMOC) system by endosulfan treatment.

Endosulfan is one of the organochlorine pesticides, which are well-known endocrine disruptors (EDs), and it acts as an estrogen agonist. Estrogen is a group of hormones that play an important role in mammary gland function and are implicated in mammary carcinogenesis. In the present study, we studied the effects of endosulfan on nodule like alveolar lesion (NLAL) formation in mouse mammary gland development using a mouse mammary gland organ culture (MMOC) system. Although endosulfan-treated mammary glands did not form NLALs, more alveolar buds were formed in this group than in the negative control (vehicle-treated) group. In addition, telomerase reverse transcriptase (TERT) mRNA expression levels were increased in endosulfan-treated mammary glands in a dose-dependent manner. Telomerase can be activated by estrogen, therefore, we examined the effects of endosulfan on telomerase activity, and found that the telomerase activity in estrogen receptor-positive MCF-7 cells was up-regulated by endosulfan treatment. Moreover, this activation was accompanied by the up-regulation of the TERT mRNA expression. Also, transient expression assays using CAT reporter plasmids containing various fragments of the TERT promoter showed that this imperfect palindromic estrogen-responsive element is almost certainly responsible for the transcriptional activation by endosulfan. These results may help elucidate the endocrine disrupting mechanism of endosulfan.

The inhibitory principle of lipopolysaccharide-induced nitric oxide production from Inula britannica var. chinensis.

A sesquiterpene lactone, 1-O-acetyl-4R,6S-britannilactone (1) isolated from the flowers of Inula britannica L. var. chinensis (Rupr.) Reg. (Compositae), was found as an iNOS inhibitory constituent for the first time with an IC50 value of 22.1 microM which is more potent than the positive control, L-N6-(1-iminoethyl)lysine (IC50 = 33.7 microM). Structure of compound 1 was identified by 1D and 2D NMR experiments and by comparison with the reference standard.

Inhibition of COX-2 activity and proinflammatory cytokines (TNF-alpha and IL-1beta) production by water-soluble sub-fractionated parts from bee (Apis mellifera) venom.

Bee venom is used as a traditional medicine for treatment of arthritis. The anti-inflammatory activity of the n-hexane, ethyl acetate, and aqueous partitions from bee venom (Apis mellifera) was studied using cyclooxygenase (COX) activity and pro-inflammatory cytokines (TNF-alpha and IL-1beta) production, in vitro. COX-2 is involved in the production of prostaglandins that mediate pain and support the inflammatory process. The aqueous partition of bee venom showed strong dose-dependent inhibitory effects on COX-2 activity (IC50 = 13.1 microg/mL), but did not inhibit COX-1 activity. The aqueous partition was subfractionated into three parts by molecular weight differences, namely, B-F1 (above 20 KDa), B-F2 (between 10 KDa and 20 KDa) and B-F3 (below 10 KDa). B-F2 and B-F3 strongly inhibited COX-2 activity and COX-2 mRNA expression in a dose-dependent manner, without revealing cytotoxic effects. TNF-alpha and IL-1beta, are potent pro-inflammatory cytokines and are early indicators of the inflammatory process. We also investigated the effects of three subfractions on TNF-alpha and IL-1beta production using ELISA method. All three subfractions, B-F1, B-F2 and B-F3, inhibited TNF-alpha and IL-1beta production. These results suggest the pharmacological activities of bee venom on anti-inflammatory process include the inhibition of COX-2 expression and the blocking of pro-inflammatory cytokines (TNF-alpha, and IL-1beta) production.

A DNA strand-nicking principle of a higher plant, Caesalpinia sappan.

To find anticancer agents from higher plants, DNA strand-scission assay method was employed for bioassay-guided fractionation as well as for screening the crude extracts. During the screening, an ethyl acetate extracts of the heartwood of Caesalpinia sappan L. (Leguminosae) exhibited potent DNA strand-scission activity. Therefore, the ethyl acetate extracts of the dried heartwood of C. sappan was subjected to the bioassay-guided fractionation, which led to the isolation of a known compound, brazilin (1) as the active constituent. In addition, caesalpine J (2) was also isolated as an inactive constituent.