Compounds with neuroprotective activity from the medicinal plant Machilus thunbergii

The Neuroprotective Effect of Isotetrandrine on Parkinson's Disease via Anti-Inflammation and Antiapoptosis In Vitro and In Vivo

Parkinson's disease (PD) is one of the most influential diseases in the world, and the current medication only can relieve the clinical symptoms but not slow the progression of PD. Therefore, we intend to examine the neuroprotective activity of plant-derived compound isotetrandrine (ITD) in vitro and in vivo. In vitro, cells were cotreated with ITD and LPS to detect the inflammatory-related protein and mRNA. In vivo, zebrafish were pretreated with ITD and inhibitors prior to 6-OHDA treatment. Then, the behavior was monitored at 5 dpf. Our result showed ITD inhibited LPS-induced upregulation of iNOS, COX-2 protein expression, and iL-6, inos, cox-2, and cd11b mRNA expression in BV2 cells. The data in zebrafish also demonstrated a significant improvement of ITD on the 6-OHDA-induced locomotor deficiency. ITD also improved 6-OHDA-induced apoptosis in zebrafish PD. We also pharmacologically validated the mechanism with three inhibitors, including LY294002, PI3K inhibitor; LY32141996, ERK inhibitor, SnPP, and HO-1 inhibitors. All of these inhibitors could abolish the neuroprotective effect of ITD partially in locomotor activity. Besides, the molecular level also showed the same trend. Treatment of these inhibitors could significantly abolish ITD-induced antineuroinflammatory and antioxidative stress effects in zebrafish PD. Our study showed ITD possessed a neuroprotective activity in zebrafish PD. The mRNA level also supported our arguments. The neuroprotection of ITD might be through antineuroinflammation and antiapoptosis pathways via PI3K, ERK, and HO-1.

Lignans from Machilus thunbergii as Thymic Stromal Lymphopoietin Inhibitors

Thymic stromal lymphopoietin (TSLP) plays an important role in the pathophysiology of various allergic diseases that are mediated by T helper cell type-2 (Th2) responses, including asthma and atopic dermatitis. The primary focus of this study was the identification of potent inhibitors of the TSLP signaling pathway for potential therapeutic use. The 80% methanol extract of Machilus thunbergii bark significantly inhibited the signal transducer and activator of transcription 5 (STAT5) phosphorylation in human mast cell (HMC)-1 cells. Through activity-guided isolation, three lignans (1-3) were obtained and identified as (+)-galbelgin (1), meso-dihydroguaiaretic acid (2), and machilin A (3). Among them, two lignans (1 and 2) significantly inhibited STAT5 phosphorylation and TSLP/TSLPR interaction, as determined by ELISA. Our results indicated that lignans isolated from M. thunbergii are a promising resource for the treatment of allergic diseases.

Tyrosol as a Neuroprotector: Strong Effects of a "Weak" Antioxidant

The use of neuroprotective agents for stroke is pathogenetically justified, but the translation of the results of preclinical studies of neuroprotectors into clinical practice has been a noticeable failure. One of the leading reasons for these failures is the one-target mechanism of their activity. p-Tyrosol (Tyr), a biophenol, is present in a variety of natural sources, mainly in foods, such as olive oil and wine. Tyr has a wide spectrum of biological activity: antioxidant, stress-protective, anti-inflammatory, anticancer, cardioprotective, neuroprotective and many others. This review analyzes data on the neuroprotective, antioxidant, anti-inflammatory, anti-apoptotic and other kinds of Tyr activity as well as data on the pharmacokinetics of the substance. The data presented in the review substantiate the acceptability of tyr as the basis for the development of a new neuroprotective drug with multitarget activity for the treatment of ischemic stroke. Tyr is a promising molecule for the development of an effective neuroprotective agent for use in ischemic stroke.

Asymmetric Synthesis of Natural and Unnatural Dibenzylbutane Lignans from a Common Intermediate

Lignans are a structurally diverse class of natural products with extensive pharmacological effects. Here we report the syntheses of both natural and unnatural dibenzylbutane lignans from a common intermediate, which is prepared in five steps from known materials. Derivatization of this intermediate affords lignans featuring contiguous stereocenters in a high diastereomeric purity after chromatography. This divergent synthetic route can be exploited to prepare dibenzylbutane lignans and analogues thereof to probe their biological profiles.

Neuroprotective Lignans from the Fruits of Schisandra bicolor var. tuberculata

Nine new lignans (1-9) and ten known analogues (10-19) were isolated from the fruits of Schisandra bicolor var. tuberculata. The structures of compounds 1-9 were established on the basis of spectroscopic data analysis. The absolute configuration of compound 1 was determined by single-crystal X-ray diffraction analysis with Cu Kα irradiation techniques, and the absolute configurations of compounds 2-9 were deduced by comparing their experimental ECD spectra and optical rotations with those of compound 1 or similar compounds. All isolates were evaluated for their neuroprotective activities against CoCl₂, H₂O₂, and Aβ_25-35-induced SH-SY5Y cell injury, and were found to exhibit different degrees of neuroprotective effects. At a low concentration of 3.2 nM, compounds 3, 8, 9, and 14-19 in CoCl₂-induced, compounds 7, 8, 13, 17, and 18 in H₂O₂-induced, and compounds 2, 6, 7, 9, 10, and 12-19 in Aβ_25-35-induced SH-SY5Y cell injury models, showed statistically significant neuroprotective activities, when compared with each negative control group.

Neuroprotective effects of p-tyrosol after the global cerebral ischemia in rats

BACKGROUND

Salidroside is a biologically active compound derived from Rhodiola rosea L. Studies showed that salidroside after i.v. injection is extensively metabolized to p-tyrosol and only trace amounts of salidroside are found in the brain tissue.

OBJECTIVE

The aim of the study was to investigate the neuroprotective effects of p-tyrosol in the global cerebral ischemia-reperfusion (GCI) model.

STUDY DESIGN

A total of 103 Wistar rats were assigned to groups of sham-operated (n=10), control (n=42), p-tyrosol-treated (n=36), and pentoxifylline-treated (n=15) animals. The rats of control, p-tyrosol-treated, and pentoxifylline-treated groups received intravenously 0.9% NaCl solution, 2% solution of p-tyrosol in doses of 5mg/kg, 10mg/kg, and 20mg/kg, and pentoxifylline in a dose of 100mg/kg, respectively, daily for 5 days. Rats were examined at days 1, 3, and 5 after GCI. After evaluation of neurological deficit, animals were euthanized for morphological and biochemical characterization.

METHODS

Rats of control, p-tyrosol-treated, and pentoxifylline-treated groups were exposed to three-vessel model of GCI. Neurological deficit, numeric density of neurons in hippocampal CA1 region, and percentage of neurons with focal and total chromatolysis were studied. Biochemical study assessed contents of conjugated dienes and fluorescent products in brain homogenate.

RESULTS

In control group, only 50.0% of rats survived by day 5 after the GCI; 38.1% of survived animals had severe neurologic deficit. In brain tissue of PTX-treated rats, the levels of diene conjugates and fluorescent products were 79% and 73%, respectivley, at day 5 compared with control. Differences in diene conjugates were statistically significant compared with control. The survival rate of animals treated with 20mg/kg p-tyrosol was 82.3% at day 5 after GCI. In p-tyrosol-treated GCI rats, the numeric density of neurons in the hippocampal CA1 region was higher by 31% compared with control. The percentage of neurons with focal and total chromatolysis decreased by 27% and 43%, respectively. At day 5 after GCI, the levels of conjugated dienes and fluorescent products were significantly lower (by 37% and 45%, respectively) in group of animals treated with 20mg/kg p-tyrosol compared with control. Moderate neuroprotective effects of 5mg/kg p-tyrosol administration were documented only at day 5 after GCI. In case of 10mg/kg p-tyrosol administration, neuroprotection was documented sooner: at day 1 or 3 after GCI. However, administration of 5 and 10mg/kg p-tyrosol did not affect animal survival.

CONCLUSION

Course administration of intravenous p-tyrosol in a dose of 20mg/kg increased survival, reduced neurological deficit after GCI, attenuated neuronal damage in the hippocampus, and attenuated lipid peroxidation in brain tissue in animals subject to GCI with reperfusion.

Methyl 3,4-dihydroxybenzoate promote rat cortical neurons survival and neurite outgrowth through the adenosine A2a receptor/PI3K/Akt signaling pathway

Methyl 3,4-dihydroxybenzoate (MDHB), a kind of phenolic acid compounds, has been reported to have antioxidant effects. Moreover, our previous study found that it could promote neurite outgrowth and brain-derived neurotrophic factor expression in cortical neurons of neonatal rats. In the present study, we focused on the mechanism of its neurotrophic effect; the results showed that MDHB-induced upregulation of neuronal survival and neurite outgrowth in cultured primary cortical neurons could be blocked by the adenosine A2a receptor inhibitor (ZM241385) and the phosphoinositide 3-kinase (PI3K) inhibitor (LY294002). Subsequently, we found that the upregulation of Akt phosphorylation by MDHB could be suppressed by A2a-R and PI3K-specific inhibitor, but not the Trk-R inhibitor. Furthermore, MDHB could activate Akt in a concentration-dependent manner. These results suggested that activation of the PI3K/Akt signaling pathway may be involved in the MDHB-induced neurotrophic effects and MDHB could be a candidate compound to develop drugs for neurodegenerative disease.

Effect of gamma irradiation on phenol content, antioxidant activity and biological activity of black maca and red maca extracts (Lepidium meyenii walp)

This study was performed to determine the effects of gamma irradiation on UV spectrum on maca, total content of polyphenols, 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical-scavenging activities and in vivo biological activities of red and black maca extracts (Lepidium meyenii). Adult mice of the strain Swiss aged 3 months and weighing 30-35 g in average were used to determine biological activities. Daily sperm production, effect on testosterone-induced prostate hyperplasia and forced swimming test were used to determine the effect of irradiation on biological activities of maca extracts. Irradiation did not show differences in UV spectrum but improves the amount of total polyphenols in red maca as well as in black maca extracts. In both cases, black maca extract has more content of polyphenols than red maca extract (p < 0.01). Gamma irradiation significantly increased the antioxidant capacity (p < 0.05). No difference was observed in daily sperm production when irradiated and nonirradiated maca extract were administered to mice (p > 0.05). Black maca extract but not red maca extract has more swimming endurance capacity in the forced swimming test. Irradiation of black maca extract increased the swimming time to exhaustion (p < 0.05). This is not observed with red maca extract (p > 0.05). Testosterone enanthate (TE) increased significantly the ventral prostate weight. Administration of red maca extract in animals treated with TE prevented the increase in prostate weight. Irradiation did not modify effect of red maca extract on prostate weight (p > 0.05). In conclusion, irradiation does not alter the biological activities of both black maca and red maca extracts. It prevents the presence of microorganisms in the extracts of black or red maca, but the biological activities were maintained.

Therapeutic and Prophylactic Potential of Morama (Tylosema esculentum): A Review

Tylosema esculentum (morama) is a highly valued traditional food and source of medicine for the San and other indigenous populations that inhabit the arid to semi-arid parts of Southern Africa. Morama beans are a rich source of phenolic acids, flavonoids, certain fatty acids, non-essential amino acids, certain phytosterols, tannins and minerals. The plant's tuber contains griffonilide, behenic acid and starch. Concoctions of extracts from morama bean, tuber and other local plants are frequently used to treat diarrhoea and digestive disorders by the San and other indigenous populations. Information on composition and bioactivity of phytochemical components of T. esculentum suggests that the polyphenol-rich extracts of the bean testae and cotyledons have great potential as sources of chemicals that inhibit infectious microorganisms (viral, bacterial and fungal, including drug-resistant strains), offer protection against certain non-communicable diseases and promote wound healing and gut health. The potential antinutritional properties of a few morama components are also highlighted. More research is necessary to reveal the full prophylactic and therapeutic potential of the plant against diseases of the current century. Research on domestication and conservation of the plant offers new hope for sustainable utilisation of the plant.

Nectandrin A Enhances the BMP-Induced Osteoblastic Differentiation and Mineralization by Activation of p38 MAPK-Smad Signaling Pathway

Osteoblastic activity of nectandrin A was examined in C2C12 cells. Nectandrin A enhances the BMP-induced osteoblastic differentiation and mineralization, manifested by the up-regulation of differentiation markers (alkaline phosphatase and osteogenic genes) and increased calcium contents. In C2C12 cells co-transfected with expression vector encoding Smad4 and Id1-Luc reporter, nectandrin A increased Id1 luciferase activity in a concentration-dependent manner, when compared to that in BMP-2 treated cells, indicating that Smad signaling pathway is associated with nectandrin A-enhanced osteoblastic differentiation in C2C12 cells. In addition, nectandrin A activated p38 mitogen-activated protein kinase (MAPK) in time- and concentration-dependent manners, and phosphorylated form of pSmad1/5/8 and alkaline phosphatase activity were both decreased when the cells were pretreated with SB203580, a p38 MAPK inhibitor, suggesting that p38 MAPK might be an upstream kinase for Smad signaling pathway. Taken together, nectandrin A enhances the BMP-induced osteoblastic differentiation and mineralization of C2C12 cells via activation of p38 MAPK-Smad signaling pathway, and it has a therapeutic potential for osteoporosis by promoting bone formation.