ABSTRACT
The "toxicity" and safety of traditional Chinese medicines have been seriously concerned. Alkaloids are the main pharmacodynamic components of many kinds of traditional Chinese medicines, which show strong biological activity at low concentration. It will also cause toxic side effects but if used improperly. Some alkaloids are both active and toxic, and the safety of related traditional Chinese medicines is particularly noteworthy. The efficacy or toxicity of alkaloids may be the result of the combined action of parent compounds and metabolites, which is not only related to the structural types of compounds, but also has obvious species differences between humans and animals. This review focused on the alkaloids contained in the "toxic" traditional Chinese medicines that are officially recorded in Chinese Pharmacopoeia and the metabolism patterns of alkaloids with different structures as well as the enzymes involved were summarized and discussed by referencing the publications in recent two decades. The present study will be beneficial to the rational use of these traditional Chinese medicines in clinic.
ABSTRACT
Objective: To analyze the change rule of main chemical components in Asarum heterotropoidesvar.mandshuricum seedling during the growing process.Method:Whole seedling samples (one week and two weeks) and the mature plant (three months) of A.heterotropoidesvar.mandshuricum were collected and every sample was divided to aerial part (stems and leaves) and underground part (roots).The secondary metabolites were qualitatively identified by HPLC-TOF-MS and the quantitative identification was carried out at the same time with asarinin as index component.Result: A total of 6 known compounds were identified from the underground part of A.heterotropoidesvar.mandshuricum as α-asarone (1),N-isobutyl-2,4,8,10-dodecatetraenamide (2),9-methoxyaristolactam Ⅳ(3),asarinin (4),caulesnarinside (6) and chalcononaringenin 2',4'-di-O-β-D-glucopyranoside (7),respectively,the peak area values showed that the contents of these compounds increased gradually with the growth time.A total of 4 known compounds were identified from the aerial part of this herb as N-isobutyl-2,4,8,10-dodecatetraenamide (2),caulesauroneside (5),caulesnarinside (6) or chalcononaringenin 2',4'-di-O-β-D-glucopyranoside (7) and peonidin 3-caffeoylgentiobioside (8).Asarinin was identified only in the underground part of mature plant,its content was 155.4 μg·g-1.Conclusion: The species and contents of secondary metabolites are quite different in the aerial and underground parts of A.heterotropoidesvar.mandshuricum.At different growth stages of A.heterotropoides var.mandshuricum seedling,the types and contents of secondary metabolites in the same site are also different,while the contents of main components show an increasing trend with the growth time.
ABSTRACT
A new electrochemical method for telomerase activity assay was developed on the basis of hybridization chain reaction ( HCR)-assisted multiple signal amplification, aiming at improving the sensitivity and specificity of telomerase assay. The experiments utilized HeLa cells as original source of the telomerase in the electrochemical studies. The telomerase primer was firstly self-assembled on the surface of gold electrode. The telomerase catalyzed the elongation of the primer, producing the complementary sequences of hairpin probe H1. In this case, HCR was then initiated by interacting with two hairpin probes H1 and H2. Because both H1 and H2 were modified by biotin, horseradish peroxidase could be captured on the electrode surface through the high-affinity interaction between biotin and streptavidin, catalyzing the oxidation of o-phenylenediamine to produce 2,3-diaminophenazine. Therefore, the telomerase assay was realized by tracing the electrochemical signals with differential pulse voltammetry. This electrochemical method was of high efficiency and feasibility for detecting telomerase activity, and could trace the telomerase activity down to 10 cells/mL HeLa cells with a wide linear range. Besides, it could also easily distinguish the target enzyme from the control proteins with high specificity.
ABSTRACT
The purpose of the present study is to explore the relationship of spatial learning ability and specific electrical activities of neural oscillations in the rat. The fast and general avoidance response groups were selected on the basis of the animals' responses to the electric shock in Y type maze, and their local field potentials (LFPs) of hippocampal CA3 area were recorded by wireless telemetry before and after shock avoidance training, respectively. The components of neural oscillations related to spatial identifying and learning ability were analyzed. The results showed that, compared with the general avoidance response group, the fast avoidance response group did not show any differences of LFPs in hippocampal CA3 area before electric shock avoidance trial, but showed significantly increased percentages of 0-10 Hz and 30-40 Hz rhythm in right hippocampal CA3 area after the shock avoidance training (P < 0.01 or P < 0.05). Fast Fourier transform showed that percentage increase of 0-10 Hz band occurred mainly in θ (3-7 Hz) frequency, and 30-40 Hz frequency change was equivalent to the γ1 band. Furthermore, compared with those before training, only the percentages of β, β2 (20-30 Hz) and γ1 rhythm increased (P < 0.01 or P < 0.05) in fast avoidance response rats after training, while the θ rhythm percentage remained unchanged. In contrast, θ rhythm percentage and the large amplitude (intensity: +2.5 - -2.5 db) θ waves in right CA3 area of general avoidance response rats were significantly reduced after training (P < 0.01). These results suggest that the increased percentages of β2 and γ1 rhythm and high-level (unchanged) percentage of θ rhythm in the right hippocampus CA3 area might be related to strong spatial cognition ability of fast avoidance response rats.