Investigation of the in vitro and ex vivo acetylcholinesterase and antioxidant activities of traditionally used Lycopodium species from South America on alkaloid extracts

Ethnopharmacological relevance

The study was aimed at evaluating medicinal and therapeutic potentials of two Lycopodiaceae species, Lycopodium clavatum (L.) and Lycopodium thyoides (Humb. & Bonpl. ex Willd), both used in South American folk medicine for central nervous system conditions. Alkaloid extracts were evaluated for chemical characterization, acetylcholinesterase and antioxidant activities.

Materials and methods

The alkaloid extracts obtained by alkaline extraction were determined for each species by GC/MS examination. The evaluation of the anticholinesterase and the antioxidant activities of the extracts were tested by determining in vitro and ex vivo models. Effects on acetylcholinesterase (AChE) were tested in vitro using rat brain homogenates and ex vivo after a single administration (25, 10 and 1 mg/kg i.p.) of the alkaloid extracts in mice. The in vitro antioxidant effects were tested for the 2-deoxyribose degradation, nitric oxide (NO) interaction, 2,2-diphenyl-1-picryl hydrazyl (DPPH) radical scavenging activity and total reactive antioxidant potential (TRAP). After an acute administration (25 and 10 mg/kg i.p.) of the extracts in middle-aged (12 months) mice, the antioxidant effects were estimated through the thiobarbituric acid reactive substances test (TBARS), and the antioxidant enzymes activities for catalase (CAT) and superoxide dismutase (SOD) were measured.

Results

AChE activity was inhibited in vitro by the alkaloid-enriched extracts of both Lycopodium species in a dose and time-dependent manner in rat cortex, striatum and hippocampus. A significant inhibition was also observed in areas of the brain after acute administration of extracts, as well as decreased lipid peroxidation and increased CAT activity in the cortex, hippocampus and cerebellum. A moderate antioxidant activity was observed in vitro for the extracts. Chemically, the main alkaloids found for the two species were lycopodine and acetyldihidrolycopodine.

Conclusion

This study showed that the biological properties of the folk medicinal plants Lycopodium clavatum and Lycopodium thyoides include AChE inhibitory activity and antioxidant effects, two possible mechanisms of action in Alzheimer's related processes.     

Role of 5-lipoxygenase pathway in the regulation of RAW 264.7 macrophage proliferation

Arachidonic acid (AA) metabolites control cell proliferation, among other physiologic functions. RAW 264.7 macrophages can metabolise AA through the cyclooxygenase and lipoxygenase (LOX) pathways. We aimed to study the role of AA-metabolites derived from 5-LOX in the control of RAW 264.7 macrophage growth. Our results show that zileuton, a specific 5-LOX inhibitor, and nordihydroguaiaretic acid (NDGA), a non-specific LOX inhibitor, inhibit cell proliferation and [(3)H]-thymidine incorporation in a concentration-dependent fashion. Growth inhibition induced by NDGA can be explained by an apoptotic process, while zileuton does not seem to induce apoptosis. Moreover, these treatments delay the cell cycle, as analysed by flow cytometry. On the other hand, the leukotriene (LT) B(4) receptor antagonist U-75302, the LTD(4) receptor antagonists LY-171883 and MK-571, and the cysteinyl-LT receptor antagonist REV-5901 also inhibit cell proliferation and [(3)H]-thymidine incorporation in a concentration-dependent manner, and delay the RAW 264.7 cell cycle. However, these antagonists did not induce annexin V staining, caspase activation or DNA fragmentation. Furthermore, we demonstrated that exogenous addition of LTB(4) or LTD(4) revert the cell growth inhibition induced by zileuton or the leukotriene receptor antagonists mentioned above. Finally, we observed that LTB(4) and LTD(4), in the absence of growth factors, have pro-proliferative effects on macrophages, and we obtained preliminary evidences that this effect could be through mitogen-activated protein kinase (MAPK) and phosphatidylinositol 3-kinase (PI3K) pathways. In conclusion, our results show that the interaction between LTB(4) and LTD(4) with its respective receptor is involved in the control of RAW 264.7 macrophage growth.     

Anti-inflammatory effects of hydroalcoholic extract and two biflavonoids from Garcinia gardneriana leaves in mouse paw oedema

Garcinia gardneriana (Planch. & Triana) Zappi (Clusiaceae) is widely distributed in Brazil and used in folk medicine to treat inflammation, pain, and urinary tract and other infections. However, very few studies have analyzed these therapeutic effects. In this study, the anti-inflammatory effects of the hydroalcoholic extracts from Garcinia gardneriana (HEGG) and some of its isolated biflavonoids were evaluated. The results showed that HEGG from the leaves, bark and seeds reduced carrageenan-induced mouse paw inflammation, in addition to diminishing the myeloperoxidase activity in the stimulated tissues. The reduction of neutrophil infiltration by treatment with the HEGG from leaves was confirmed by histology. The leaf extract also reduced the paw oedema evoked by bradykinin, histamine, prostaglandin E2 and 12-O-tetradecanoylphorbol acetate. However, it partially decreased substance P and compound 48/80-caused paw oedema, without any influence on the arachidonic acid-induced oedema. Both of the isolated compounds, fukugetin and GB-2a, prevented the carrageenan-induced paw oedema. In conclusion, this study showed important anti-inflammatory effects of HEGG through its interaction with different intracellular signaling pathways, without interfering with the formation of arachidonic acid (AA) metabolites. These characteristics, in addition to the wide distribution and culturing ease of the plant, confirm its popular use and highlight its promise in the development of new anti-inflammatory drugs.     

大鼠脾内肝细胞移植的早期组织形态学和超微结构的实验研究

目的 研究脾内移植的SV40LT抗原基因肝细胞的早期组织形态学和超微结构特点并初步探讨其机制。方法 Wistar大鼠随机分组后脾脏内移植原代肝细胞（A,B组）或SV40LT抗原基因肝细胞（C,D组）。静脉给予（B,D组）或不给予（A,C组）环胞霉素A。移植后1～14d对受体脾脏内肝细胞的组织形态及超微结构进行观察和分析。结果 静脉给予环胞霉素A的B,D组,与不给予环胞霉素A的A,C组比较,移植肝细胞的组织形态学及超微结构改变明显较小,移植肝细胞的存活数显著增高（P〈0.05）。使用环胞霉素A的D组与B组之间移植细胞的存活率在1～7d差异没有显著性（P〉0.05）,而8～14dD组与B组相比,D组细胞存活率较高（P〈0.01）。结论 SV40LT抗原基因肝细胞脾脏内移植后,在使用免疫抑制剂的情况下能长时间保持较高的存活细胞数,维持完整的组织形态学结构。     

流式细胞术检测细胞周期分析软件的比较

目的探讨流式细胞术中不同细胞周期分析软件在细胞周期分析中的特点和差异。方法采用碘化丙啶染色,在Epics XL流式细胞仪上检测细胞周期,分别应用MultiCycle和Modfit LT软件对检测数据进行分析,并比较分析结果。结果 MultiCycle和Modfit LT软件分析细胞周期各时相比例、DNA倍体分析、细胞增殖及细胞凋亡数值,比较其结果基本一致。仅人肺癌细胞系A549细胞G2/G1值应用2种不同软件分析其数据差异有统计学意义(P<0.01);Jurkat T细胞聚集体的比例应用2种不同软件分析其数据差异有统计学意义(P<0.01)。结论 MultiCycle和Modfit LT软件分析同一样本所得拟合结果有较高的一致性;对G2/G1值进行限制的操作可能更适用于组成成分较复杂的样本;虽然不同采集软件区分粘连细胞和细胞集落的方法不同,导致聚集体的比例差异显著,但并未对细胞周期分析结果的判定产生影响。     

Leukotrienes stimulate pepsinogen secretion from guinea pig gastric chief cells by a nitric oxide-dependent pathway

Leukotrienes (LTs) are involved in many inflammatory conditions including gastric damage induced by nonsteroidal anti-inflammatory drugs. Although LTs stimulate acid secretion, the effect they exert on pepsinogen secretion is unknown. The aim of this study was to investigate whether LTs stimulate pepsinogen secretion by isolated chief cells and to identify the intracellular messengers that mediate this action. Isolated chief cells were incubated with concentrations of LTB₄, LTC₄, LTD₄, or LTE₄ ranging from 0.1 pmol/L to 10 μmol/L, and pepsinogen release, intracellular calcium and inositol(1,4,5)-trisphosphate (IP₃) concentrations were measured. Nitric oxide generation was determined by the amount of citrulline generated during incubation. All four LTs caused a concentration-dependent stimulation of pepsinogen secretion with 50% effective concentration of 0.05-0.1 nmol/L and a dose-dependent increase in cytoplasmic free calcium and IP₃ concentration. The LTB₄ and LTD₄ antagonists caused selective, concentration-dependent inhibition of LTB₄- and LTD₄-induced pepsinogen secretion, calcium mobilization, and IP₃ generation. All four LTs increased NO generation, and the effect was inhibited by LTB₄ and LTD₄ antagonists and an NO synthase inhibitor N^G-monomethyl-l-arginine and reversed by l-arginine. N^G-monomethyl-l-arginine caused a 50%–60% reduction of LT-induced pepsinogen release. Each of the four LTs caused a fivefold increase in 5′-cyclic guanosine monophosphate. LTs are powerful stimulators of pepsinogen secretion in isolated chief cells and act via occupancy of specific cell-surface receptors.     

New-Onset Diabetes and Preexisting Diabetes Are Associated With Comparable Reduction in Long-Term Survival After Liver Transplant: A Machine Learning Approach

Objective

To identify key predictors and survival outcomes of new-onset diabetes after transplant (NODAT) in liver transplant (LT) recipients by using the Scientific Registry of Transplant Recipients.

Longitudinal Recovery and Reduced Costs After 120 Sessions of Locomotor Training for Motor Incomplete Spinal Cord Injury

Objective

To determine the impact of long-term, body weight–supported locomotor training after chronic, incomplete spinal cord injury (SCI), and to estimate the health care costs related to lost recovery potential and preventable secondary complications that may have occurred because of visit limits imposed by insurers.

Investigation of osteoclastogenic signalling of the RANKL substitute LIGHT

LIGHT (TNFSF14) is a member of the TNF superfamily and is known to substitute for RANKL to induce osteoclast differentiation. LIGHT binds HVEM and LTβR, but it is not known whether these receptors play a role in osteoclast formation or whether LIGHT acts via RANKL signalling pathways. We found that both RANKL and LIGHT strongly induced phosphorylation of Akt and NFκB but not JNK in mouse osteoclast precursor cells. The addition of an Akt inhibitor showed decreased osteoclast differentiation and resorption mediated by both RANKL and LIGHT. RT-PCR and FACS analysis showed that CD14⁺ human osteoclast precursors expressed HVEM and LTβR; expression levels of HVEM increased in the course of osteoclastogenesis and a decrease in LIGHT expression was associated with an increase in HVEM suggesting that there is a feedback loop related to this receptor. Our findings show that LIGHT is not inhibited by the soluble RANKL receptor OPG and that LIGHT is a potent osteoclastogenesis factor that activates the Akt, NFκB and JNK pathways.