Jing Tong

Comparative Analysis of Essential Oil Components and Antioxidant Activity of Extracts of Nelumbo nucifera from Various Areas of China

This study was designed to examine the composition of extracts and essential oil components from Nelumbo nucifera leaves from the principal habitats in China. The amounts of phenolics, flavonoids, and proanthocyanidins in the lotus leaf extracts varied widely, ranging from 354 to 487 mg/g gallic acid equivalents, from 172 to 236 mg/g rutin equivalents, and from 124 to 179 mg/g catechin equivalents, respectively. All of the extracts had strong antioxidant activity in comparison to the standard compounds butylated hydroxytoluene and vitamin C. Wild lotus samples from Baiyangdian Lake and Weishan Lake exhibited a stronger free radical scavenging effect and greater reducing power than the cultural samples, but no such differences were observed in the inhibition of lipid oxidation. Chemical variation in the essential oils from the various samples was analyzed by GC-MS. The main constituents were l-(+)-ascorbic acid 2,6-dihexadecanoate (0-33.5%), trans-phytol (5.1-24.1%), hexahydrofarnesyl acetone (5.6-15.3%), pentadecyl acrylate (2.2-12.4%), geranyl acetone (1.9-8.0%), and beta-ionone (0-8.0%). The rhizome lotus and seed lotus samples were clustered into separate groups by hierarchical cluster analysis according to the composition of the corresponding essential oils. No significant relationship was found between essential oil composition and geographical distribution of the 11 populations. However, the results indicated that region of origin and growing conditions could significantly affect both the bioactivities of the lotus leaf and the content of bioactive compounds in the leaves. Thus, the existence of chemical polymorphism in the N. nucifera leaf in China was demonstrated.

Hepatoprotective activity of flavonoids from Cichorium glandulosum seeds in vitro and in vivo carbon tetrachloride-induced hepatotoxicity.

ETHNOPHARMACOLOGICAL RELEVANCE Cichorium glandulosum Boiss. et Huet was used historically in Uyghur folk medicine. Its roots, seeds, and aerial parts are extensively used by Uyghur residents in Xinjiang to eliminate savda typhoid, dredge and cure obstructive jaundice variety liver disorders. AIM OF THE STUDY To evaluate the hepatoprotective activity of total flavonoids (TFs) obtained from C. glandulosum seeds against carbon tetrachloride (CCl4)-induced liver damage in vitro and in vivo. To investigate the mechanisms of hepatoprotective effects for TFs. MATERIALS AND METHODS The dried seeds of C. glandulosum were extracted with 70% aqueous ethanol, and the extract was chromatographed with D101 macroporous resin. In vitro the antioxidant capacity against lipid peroxidation (LPO) was evaluated using ferrothiocyanate, thiobarbituric acid, β-carotene bleaching, and LPO inhibition assay. The cytotoxicity and hepatoprotective activity of TFs were evaluated in human liver hepatoma cells (HepG2). MTT assay, hepatic injury markers aspartate aminotransferase (AST), alanine aminotransaminase (ALT), lactate dehydrogenase (LDH) leakage, malondialdehyde (MDA), and glutathione (GSH) were performed. In vivo the hepatoprotective activity of TFs against CCl4-induced acute liver injury was evaluated in rats. A series of biochemical and antioxidant parameter levels were measured in liver homogenate. The suppressive effect on pancreatic lipase activity was determined. RESULTS Results indicated that TFs showed antioxidant capacity against lipid peroxidation (LPO). Administrating CCl4 (1%, v/v) caused a significant decrease in HepG2 viability. Treatment with TFs at doses (62.5, 125, and 250 μg/ml) could significantly ameliorate the cytotoxicity and decline the levels of AST, ALT, and LDH induced by CCl4. The markers including MDA and GSH, which were close to oxidative damage, were restored. Oral treatment with TFs in vivo at doses of 100, 200, and 400 mg/kg significantly reduced the levels of AST, ALT, alkaline phosphatase (ALP), total bilirubin (TB), and thiobarbituric acid reactive substances (TBARs) in the serum compared with CCl4-induced acute liver injury in rats. TFs showed dose-dependent suppressive effects on pancreatic lipase activity, and the IC50 was 1.318 ± 0.164 mg/ml. CONCLUSION TFs from C. glandulosum seeds demonstrated significant hepatoprotection against CCl4-induced hepatotoxicity. TFs exhibited significant suppression of LPO and pancreatic lipase capacity, which may be the mechanisms of hepatoprotective effects against CCl4. Our results contribute towards validation of the traditional use of C. glandulosum seeds in the treatment of liver disorders.

In vitro evaluation of inorganic and methyl mercury mediated cytotoxic effect on neural cells derived from different animal species

To extend the current understanding of the mercury-mediated cytotoxic effect, five neural cell lines established from different animal species were comparatively analyzed using three different endpoint bioassays: thiazolyl blue tetrazolium bromide, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide assay (MTT), neutral red uptake assay (NRU), and Coomassie blue assay (CB). Following a 24-hr exposure to selected concentrations of mercury chloride (HgCl2) and methylmercury (II) chloride (MeHgCl), the cytotoxic effect on test cells was characterized by comparing their 50% inhibition concentration (IC50) values. Experimental results indicated that both these forms of mercury were toxic to all the neural cells, but at very different degrees. The IC50 values of MeHgCl among these cell lines ranged from 1.15±0.22 to 10.31±0.70μmol/L while the IC50 values for HgCl2 were much higher, ranging from 6.44±0.36 to 160.97±19.63μmol/L, indicating the more toxic nature of MeHgCl. The IC50 ratio between HgCl2 and MeHgCl ranged from 1.75 to 96.0, which confirms that organic mercury is much more toxic to these neural cells than inorganic mercury. Among these cell lines, HGST-BR and TriG44 derived from marine sea turtles showed a significantly high tolerance to HgCl2 as compared to the three mammalian neural cells. Among these neural cells, SK-N-SH represented the most sensitive cells to both chemical forms of mercury.

Monocytes-Derived Macrophages Mediated Stable Expression of Human Brain-Derived Neurotrophic Factor, a Novel Therapeutic Strategy for NeuroAIDS

HIV-1 associated dementia remains a significant public health burden. Clinical and experimental research has shown that reduced levels of brain-derived neurotrophic factor (BDNF) may be a risk factor for neurological complications associated with HIV-1 infection. We are actively testing genetically modified macrophages for their possible use as the cell-based gene delivery vehicle for the central nervous system (CNS). It can be an advantage to use the natural homing/migratory properties of monocyte-derived macrophages to deliver potentially neuroprotective BDNF into the CNS, as a non-invasive manner. Lentiviral-mediated gene transfer of human (h)BDNF plasmid was constructed and characterized. Defective lentiviral stocks were generated by transient transfection of 293T cells with lentiviral transfer plasmid together with packaging and envelope plasmids. High titer lentiviral vector stocks were harvested and used to transduce human neuronal cell lines, primary cultures of human peripheral mononocyte-derived macrophages (hMDM) and murine myeloid monocyte-derived macrophages (mMDM). These transduced cells were tested for hBDNF expression, stability, and neuroprotective activity. The GenomeLab GeXP Genetic Analysis System was used to evaluate transduced cells for any adverse effects by assessing gene profiles of 24 reference genes. High titer vectors were prepared for efficient transduction of neuronal cell lines, hMDM, and mMDM. Stable secretion of high levels of hBDNF was detected in supernatants of transduced cells using western blot and ELISA. The conditioned media containing hBDNF were shown to be protective to neuronal and monocytic cell lines from TNF-α and HIV-1 Tat mediated cytotoxicity. Lentiviral vector-mediated gene transduction of hMDM and mMDM resulted in high-level, stable expression of the neuroprotective factorBDNF in vitro. These findings form the basis for future research on the potential use of BDNF as a novel therapy for neuroAIDS.

Dicaffeoylquinic Acid-Enriched Fraction of Cichorium glandulosum Seeds Attenuates Experimental Type 1 Diabetes via Multipathway Protection.

Chicory has a major geographical presence in Europe and Asia. Cichorium glandulosum Boiss. et Huet, a genus Cichorium, is used for medicinal and food purposes in Asia. In this study, a dicaffeoylquinic acid-enriched fraction of C. glandulosum seeds n-BuOH fraction (CGSB) could ameliorate type 1 diabetes mellitus (T1DM) in streptozotocin (STZ)-induced diabetic mice with continuous administration for 2 weeks. CGSB treatment showed significantly higher plasma insulin levels but lower free fatty acids in adipose tissue and liver. Moreover, CGSB improved pancreatic islet mass. In vitro, different fractions of C. glandulosum seed (CGS) induced the differentiation of 3T3-L1 preadipocytes. The mRNA level for peroxisome proliferator-activated receptor alpha increased in high glucose treatment group in HepG2 cells, while CGSB significantly down-regulated the mRNA expression. The main compound of CGSB, 3,5-dicaffeoylquinic acid, was isolated and identified, which exhibited α-glucosidase inhibitory activity. These findings demonstrated that CGSB attenuated experimental T1DM via multipathway protection.