Neuroprotective phenylpropanoid esters of rhamnose isolated from roots of Scrophularia buergeriana

Neurotrophic Natural Products

Neurotrophins (NGF, BDNF, NT3, NT4) can decrease cell death, induce differentiation, as well as sustain the structure and function of neurons, which make them promising therapeutic agents for the treatment of neurodegenerative disorders. However, neurotrophins have not been very effective in clinical trials mostly because they cannot pass through the blood-brain barrier owing to being high-molecular-weight proteins. Thus, neurotrophin-mimic small molecules, which stimulate the synthesis of endogenous neurotrophins or enhance neurotrophic actions, may serve as promising alternatives to neurotrophins. Small-molecular-weight natural products, which have been used in dietary functional foods or in traditional medicines over the course of human history, have a great potential for the development of new therapeutic agents against neurodegenerative diseases such as Alzheimer's disease. In this contribution, a variety of natural products possessing neurotrophic properties such as neurogenesis, neurite outgrowth promotion (neuritogenesis), and neuroprotection are described, and a focus is made on the chemistry and biology of several neurotrophic natural products.

Scrophularia peyronii Post. from Jordan: Chemical Composition of Essential Oil and Phytochemical Profiling of Crude Extracts and Their In Vitro Antioxidant Activity

The genus Scrophularia is one of the largest genera belonging to the Scrophulariaceae family. Different members of the genus exhibit an interesting, wide spectrum of bioactivities. Accordingly, the current study aimed to investigate, for the first time, the chemical composition of the essential oil of Scrophularia peyronii Post. from Jordan. Additionally, extracts obtained from the aerial parts with solvents of different polarities were assayed for their phytochemical constituents and in vitro antioxidant activities. The major constituents detected in the essential oil, as revealed by GC/MS analysis, contained mainly Z,Z-farnesyl acetone (11.04%), β-elemene (6.36%), n-octanal (5.98%), and spathulenol (4.58%). Each of the aqueous methanol (Sp-M) and butanol (Sp-B) extracts contained flavonoids, saponins, anthraquinone, and glycosides. Both extracts were evaluated for their total phenolic content (TPC), total flavonoid content (TFC), and their in vitro antioxidant activity, which were assayed using the DPPH radical scavenging activity and ABTS radical scavenging methods. Additionally, the two extracts were then subjected to LC-ESI-MS/MS for the qualitative determination of their secondary metabolite content, especially in flavonoids and phenolic compounds. The results showed that the Sp-B extract of S. peyronii had the highest contents of both phenolic compounds and flavonoids and showed high radical scavenging activity, as determined by the two assay methods, when compared with the Sp-M extract. The LC-ESI-MS/MS analysis resulted in the detection of 21 compounds, including 8 flavonoids, 6 phenolic acids, 6 iridoids, and 2 acids. Although the majority of compounds were detected in both extracts, it was noticed that scropolioside B, 6'-O-cinnamoylharpagide, isoferulic acid, and 6-O-methylcatapol were only detected in the Sp-M fraction.

Rhamnopyranoside-Based Fatty Acid Esters as Antimicrobials: Synthesis, Spectral Characterization, PASS, Antimicrobial, and Molecular Docking Studies

The most widely used and accessible monosaccharides have a number of stereogenic centers that have been hydroxylated and are challenging to chemically separate. As a result, the task of regioselective derivatization of such structures is particularly difficult. Considering this fact and to get novel rhamnopyranoside-based esters, DMAP-catalyzed di-O-stearoylation of methyl α-l-rhamnopyranoside (3) produced a mixture of 2,3-di-O- (4) and 3,4-di-O-stearates (5) (ratio 2:3) indicating the reactivity of the hydroxylated stereogenic centers of rhamnopyranoside as 3-OH > 4-OH > 2-OH. To get novel biologically active rhamnose esters, di-O-stearates 4 and 5 were converted into six 4-O- and 2-O-esters 6-11, which were fully characterized by FT-IR, ¹H, and ¹³C NMR spectral techniques. In vitro antimicrobial assays revealed that fully esterified rhamnopyranosides 6-11 with maximum lipophilic character showed better antifungal susceptibility than antibacterial activity. These experimental findings are similar to the results found from PASS analysis data. Furthermore, the pentanoyl derivative of 2,3-di-O-stearate (compound 6) showed better antifungal functionality against F. equiseti and A. flavus, which were found to be better than standard antibiotics. To validate the better antifungal results, molecular docking of the rhamnose esters 4-11 was performed with lanosterol 14α-demethylase (PDB ID: 3LD6), including the standard antifungal antibiotics ketoconazole and fluconazole. In this instance, the binding affinities of 10 (-7.6 kcal/mol), 9 (-7.5 kcal/mol), and 7 (-6.9 kcal/mol) were better and comparable to fluconazole (-7.3 kcal/mol), indicating the likelihood of their use as non-azole type antifungal drugs in the future.

Novel Galactopyranoside Esters: Synthesis, Mechanism, In Vitro Antimicrobial Evaluation and Molecular Docking Studies

One-step direct unimolar valeroylation of methyl α-D-galactopyranoside (MDG) mainly furnished the corresponding 6-O-valeroate. However, DMAP catalyzed a similar reaction that produced 2,6-di-O-valeroate and 6-O-valeroate, with the reactivity sequence as 6-OH > 2-OH > 3-OH,4-OH. To obtain novel antimicrobial agents, 6-O- and 2,6-di-O-valeroate were converted into several 2,3,4-tri-O- and 3,4-di-O-acyl esters, respectively, with other acylating agents in good yields. The PASS activity spectra along with in vitro antimicrobial evaluation clearly indicated that these MDG esters had better antifungal activities than antibacterial agents. To rationalize higher antifungal potentiality, molecular docking was conducted with sterol 14α-demethylase (PDB ID: 4UYL, Aspergillus fumigatus), which clearly supported the in vitro antifungal results. In particular, MDG ester 7−12 showed higher binding energy than the antifungal drug, fluconazole. Additionally, these compounds were found to have more promising binding energy with the SARS-CoV-2 main protease (6LU7) than tetracycline, fluconazole, and native inhibitor N3. Detailed investigation of Ki values, absorption, distribution, metabolism, excretion, and toxicity (ADMET), and the drug-likeness profile indicated that most of these compounds satisfy the drug-likeness evaluation, bioavailability, and safety tests, and hence, these synthetic novel MDG esters could be new antifungal and antiviral drugs.

A mixture of Panax ginseng and Scrophularia buergeriana improves immune function in an immunosuppressed murine model

BACKGROUND

Immunomodulatory drugs are currently used for immunosuppressed individuals, but adverse side effects have been reported. Although Panax ginseng and Scrophularia buergeriana are known to have respective pharmacological properties, the potential of a mixture of Panax ginseng and Scrophularia buergeriana (Isam-Tang, IST) as an immunomodulatory drug has not yet been studied.

PURPOSE

The present study was designed to assess the immunomodulatory activity of IST and p-coumaric acid (pCA), an active compound of IST, in the immune system.

METHODS

The levels of immunostimulatory cytokines, nitrite, inducible nitric oxide synthase (iNOS), NF-kB activation, and proliferation were examined in RAW264.7 cells, primary splenocytes and splenic NK cells isolated from normal mouse spleen, and in cyclophosphamide-induced immunosuppressed mice using ELISA, quantitative real-time PCR, Western blotting, and immunofluorescence staining.

RESULTS

IST or pCA treatment increased the production of immunostimulatory cytokines and nitrite and the expression of iNOS in RAW264.7 cells and splenocytes. IST or pCA also induced NF-κB signaling activation and promoted the phagocytic activity of RAW264.7 cells. In addition, the splenocyte proliferation and splenic NK activity were enhanced by IST or pCA. IST or pCA increased the levels of immunostimulatory cytokines in immunosuppressed mice and ameliorated splenic tissue damage.

CONCLUSION

These findings suggest that IST supplementation may be used to enhance immune function.

Role of NMDA Receptors in Alzheimer's Disease Pathology and Potential NMDA Receptor Blockers from Medicinal Plants - A Review

<p>Alzheimer’s disease is responsible for 60-70 percent of dementia cases worldwide. Globally, there are 24.3 million cases. Researchers have attempted to develop multi-target medications to suppress several mechanisms in Alzheimer’ Disease, like protein mis-folding and related beta amyloid aggregation, oxidative stress, and decreasing Acetyl choline levels. NMDA-mediated neurotoxicity is often linked to cognitive impairment, as shown in Alzheimer’s disease. NMDA receptors found to have to connection with beta amyloid peptide and tau protein deposition which are major characteristics of Alzheimer’s disease. NMDA receptor antagonists are a viable therapy option for a many neurological disorders, as well as Alzheimer’s disease. Currently, majority of the drugs used in the management of Alzheimer’s disease are Acetyl choline Esterase inhibitors. Memantine is the only approved NMDA blocker, to be used in Alzheimer’s disease, which is found to be effective only to a certain extend. There is a need for better therapeutic agents belonging to this class. This paper intends to provide a rapid reference about the involvement of NMDA receptors in the pathogenesis of Alzheimer’s disease, as well as phyto constituents that have been identified to inhibit NMDA receptors.</p>

Recent Developments in Therapeutic and Nutraceutical Applications of p-Methoxycinnamic Acid from Plant Origin

The p-methoxycinnamic acid (p-MCA) is one of the most studied phenylpropanoids with high importance not only in the wide spectrum of therapeutic activities but also its potential application for the food industry. This natural compound derived from plants exhibits a wide range of biologically useful properties; therefore, during the last two decades it has been extensively tested for therapeutic and nutraceutical applications. This article presents the natural sources of p-MCA, its metabolism, pharmacokinetic properties, and safety of its application. The possibilities of using this dietary bioactive compound as a nutraceutical agent that may be used as functional food ingredient playing a vital role in the prevention and treatment of many chronic diseases is also discussed. We present the antidiabetic, anticancer, antimicrobial, hepato-, and neuroprotective activities of p-MCA and methods of its lipophilization that have been developed so far to increase its industrial application and bioavailability in the biological systems.

Biological Properties, Health Benefits and Enzymatic Modifications of Dietary Methoxylated Derivatives of Cinnamic Acid

Methoxylated derivatives of cinnamic acid play an important role in the formation of the pro-health potential of food products. Numerous reports present them as molecules with strong antimicrobial, antidiabetic, anticancer as well as hepato-, cardio-, and neuroprotective activities. In the last three decades, many research groups have tried to extend the practical application of these molecules as therapeutic and antioxidant agents extensively studying the methods of their lipophilization as the solution of problems of their low oral bioavailability and rapid metabolism. This article summarizes the latest data of natural sources of occurrence, biological potential and bioavailability of methoxy derivatives of cinnamic acids. Metabolism and pharmacokinetics of this group of dietary compounds are also extensively discussed as well as reviewing the methods of their chemical and enzymatic lipophilization in the aspect of their use in food and pharmaceutical industries.

Neuroprotective Effects of Coffee Bioactive Compounds: A Review

Coffee is one of the most widely consumed beverages worldwide. It is usually identified as a stimulant because of a high content of caffeine. However, caffeine is not the only coffee bioactive component. The coffee beverage is in fact a mixture of a number of bioactive compounds such as polyphenols, especially chlorogenic acids (in green beans) and caffeic acid (in roasted coffee beans), alkaloids (caffeine and trigonelline), and the diterpenes (cafestol and kahweol). Extensive research shows that coffee consumption appears to have beneficial effects on human health. Regular coffee intake may protect from many chronic disorders, including cardiovascular disease, type 2 diabetes, obesity, and some types of cancer. Importantly, coffee consumption seems to be also correlated with a decreased risk of developing some neurodegenerative conditions such as Alzheimer's disease, Parkinson's disease, and dementia. Regular coffee intake may also reduce the risk of stroke. The mechanism underlying these effects is, however, still poorly understood. This review summarizes the current knowledge on the neuroprotective potential of the main bioactive coffee components, i.e., caffeine, chlorogenic acid, caffeic acid, trigonelline, kahweol, and cafestol. Data from both in vitro and in vivo preclinical experiments, including their potential therapeutic applications, are reviewed and discussed. Epidemiological studies and clinical reports on this matter are also described. Moreover, potential molecular mechanism(s) by which coffee bioactive components may provide neuroprotection are reviewed.

Interesterification of Egg-Yolk Phosphatidylcholine with p-Methoxycinnamic Acid Catalyzed by Immobilized Lipase B from Candida Antarctica

The p-methoxycinnamic acid (p-MCA) is one of the most popular phenylpropanoids, the beneficial impact of which on the human health is well documented in the literature. This compound has shown many valuable activities including anticancer, antidiabetic, and neuro- and hepatoprotective. However, its practical application is limited by its low bioavailability resulting from rapid metabolism in the human body. The latest strategy, aimed at overcoming these limitations, is based on the production of more stability in systemic circulation bioconjugates with phospholipids. Therefore, the aim of this research was to develop the biotechnological method for the synthesis of phospholipid derivatives of p-methoxycinnamic acid, which can play a role of new nutraceuticals. We developed and optimized enzymatic interesterification of phosphatidylcholine (PC) with ethyl p-methoxycinnamate (Ep-MCA). Novozym 435 and a binary solvent system of toluene/chloroform 9:1 (v/v) were found to be the effective biocatalyst and reaction medium for the synthesis of structured p-MCA phospholipids, respectively. The effects of the other reaction parameters, such as substrate molar ratio, enzyme dosage, and reaction time, on the degree of incorporation of p-MCA into PC were evaluated by use of an experimental factorial design method. The results showed that substrate molar ratio and biocatalyst load have significant effects on the synthesis of p-methoxycinnamoylated phospholipids. The optimum conditions were: Reaction time of three days, 30% (w/w) of Novozym 435, and 1/10 substrate molar ratio PC/Ep-MCA. Under these parameters, p-methoxycinnamoylated lysophosphatidylcholine (p-MCA-LPC) and p-methoxycinnamoylated phosphatidylcholine (p-MCA-PC) were obtained in isolated yields of 32% and 3% (w/w), respectively.

Development and Optimization of Lipase-Catalyzed Synthesis of Phospholipids Containing 3,4-Dimethoxycinnamic Acid by Response Surface Methodology

The interesterification reaction of egg-yolk phosphatidylcholine (PC) with ethyl ester of 3,4-dimethoxycinnamic acid (E3,4DMCA) catalyzed by Novozym 435 in hexane as a reaction medium was shown to be an effective method for the synthesis of corresponding structured O-methylated phenophospholipids. The effects of substrate molar ratios, time of the reaction and enzyme load on the process of incorporation of 3,4DMCA into PC were evaluated by using the experimental factorial design of three factors and three levels. The results showed that a substrate molar ratio is a crucial variable for the maximization of the synthesis of 3,4-dimethoxycinnamoylated phospholipids. Under optimized parameters of 1/10 substrate molar ratio PC/E3,4DMCA, enzyme load 30% (w/w), hexane as a medium and incubation time of 3 days, the incorporation of aromatic acid into phospholipid fraction reached 21 mol%. The modified phosphatidylcholine (3,4DMCA-PC) and modified lysophosphatidylcholine (3,4DMCA-LPC) were obtained in isolated yields of 3.5% and 27.5% (w/w), respectively. The developed method of phosphatidylcholine interesterification is the first described in the literature dealing with 3,4DMCA and allows us to obtain new O-methylated phenophospholipids with potential applications as food additives or nutraceuticals with pro-health activity.

The Raman, SERS and computational studies of 3,5-dimethoxy-4-hydroxycinnamic acid and its silver complex

Optimized chemical structure, Raman and SERS spectra of 3,5-dimethoxy-4-hydroxycinnamic acid (35D4HCA) molecule and its silver (Ag) complex were calculated using time-dependent density functional theory in conjunction with B3LYP functional and LANL2DZ/6-311 + G(d,p) basis sets. Moreover, excitation and HOMO-LUMO energies were computed by the same level of theory. Because of the fact that energy of excitation electronic transition depends on infinite lifetime approximation, Raman activities were calculated under this approximation. Normal Raman spectra and SERS spectra of 35D4HCA and its silver complex were obtained with different excitation laser frequencies such as 532 nm and 785 nm and so interaction between metal surface and 35D4HCA was examined using SERS spectra. Moreover, theoretical and experimental UV-VIS spectra in the water of 35D4HCA and its silver complex were obtained and transitions, wavelengths and energy values of samples were shown. ¹H NMR experiment of 35D4HCA and its silver complex were performed and it was determined interaction between Ag atoms and 35D4HCA. In order to determine thermal properties of 35D4HCA and its silver complex, TG and DTA analysis were carried out. HOMO and LUMO energy levels corresponding to these energy values were determined and transitions between these levels were determined.

Neuromodulatory potential of phenylpropanoids; para-methoxycinnamic acid and ethyl-p-methoxycinnamate on aluminum-induced memory deficit in rats

Para-methoxycinnamic acid (PMCA) and Ethyl-p-methoxycinnamate (EPMC) are reported to possess neuroprotective effect in reversing an acute memory deficit. However, there is a dearth of evidence for their therapeutic effect in chronic memory deficit. Thus, there is a scope to study these derivatives against the chronic model of cognitive dysfunction. The present study was aimed to determine the cognitive enhancing activity of PMCA and EPMC in aluminum-induced chronic dementia. Cognitive enhancing property of PMCA and EPMC was assessed using Morris water maze by analyzing spatial memory parameters such as escape latency, D-quadrant latency, and island entries. To find a possible mechanism, the effect of test compounds on altered acetylcholinesterase (AChE) activity and oxidative stress was determined in the hippocampus and frontal cortex of rats. Docking interaction of these derivatives with acetylcholinesterase enzyme and glutamate receptors was also studied. Treatment with PMCA and EPMC showed a significant improvement in spatial memory markers and altered hippocampal AChE activity in rats with cognitive dysfunction. The implication of hippocampal and cortical oxidative stress in memory impairment was confirmed with decreased catalase/increased thiobarbituric acid reactive substances (TBARS) in rats. PMCA and EPMC reversed the oxidative stress in the brain by negatively affecting TBARS levels. Against depleted catalase levels, PMCA was more effective than EPMC in raising the depleted catalase levels. In silico analysis revealed poor affinity of EPMC and PMCA with AChE enzyme and glutamate receptor. To conclude, PMCA and EPMC exerted cognitive enhancing property independent of direct AChE and glutamate receptor inhibition.

Chemical Composition of Scrophularia lucida and the Effects on Tumor Invasiveness in Vitro

A detannified methanolic extract of Scrophularia lucida L. attenuated the formation of cancer cell-induced circular chemorepellent induced defects (CCIDs) in the lymph endothelial cell barrier, which resemble entry ports for the intravasating tumor into the vasculature as a prerequisite for lymph node metastasis. Therefore, the composition of this extract was studied in an activity-guided approach. Since no data on the secondary metabolites of this plant were available, first phytochemical data were collected in the course of the fractionation of the extract. The study resulted in the identification of 14 substances, among them very rare iridoids, such as scrovalentinoside or koelzioside, and several flavonoids (e.g., nepitrin and homoplantaginin). One of the latter group, 2″-O-acetyl-homoplantaginin, is a new natural compound. In the most active fraction, the flavonoid hispidulin was identified as major component and the assay of the pure compound confirmed a contribution of hispidulin to the CCID-inhibitory effects of S. lucida. The activity of the two major iridoids in this assay was less compared to hispidulin.

E-p-Methoxycinnamoyl-α-l-rhamnopyranosyl Ester, a Phenylpropanoid Isolated from Scrophularia buergeriana, Increases Nuclear Factor Erythroid-Derived 2-Related Factor 2 Stability by Inhibiting Ubiquitination in Human Keratinocytes

The nuclear factor erythroid-derived 2-related factor 2 (Nrf2) is a key regulator of gene expression during oxidative stress and drug detoxification. Thus, identifying Nrf2 activators to protect from possible cell damage is necessary. In this study, we investigated whether E-p-methoxycinnamoyl-α-l-rhamnopyranosyl ester (MCR), a phenylpropanoid isolated from Scrophularia buergeriana, can activate Nrf2 signaling in human keratinocytes (HaCaT). First, we determined the dose- and time-dependent effects of MCR on the expression and activity of Nrf2. The antioxidant response element-luciferase reporter assay and western blot analysis results showed that MCR markedly induced Nrf2 activity and its protein expression, respectively. Further, MCR increased both the mRNA and protein levels of heme-oxygenase-1, one of the Nrf2 target genes, in the cells. Interestingly, we found that Nrf2 stability was remarkably enhanced by MCR. Furthermore, ubiquitin-dependent proteasomal degradation of Nrf2 was significantly reduced by MCR. Thus, MCR might afford skin protection by enhancing Nrf2 stability or by blocking its proteasomal degradation.

Two pairs of unusual melibiose and raffinose esters from Scrophularia ningpoensis

A pair of unusual melibiose esters (1α/1β) and a pair of unusual raffinose esters (2α/2β), were isolated from Scrophularia ningpoensis. Structures of them were established by detailed spectroscopic analyses to be 6-O-(E)-cinnamoyl-α-d-galactopyranosyl-(1→6)-α(β)-d-glucopyranose (1α/1β) and 6-O-(E)/(Z)-cinnamoyl-α-d-galactopyranosyl-(1→6)-α-d-glucopyranosyl-(1→2)-β-d-fructofuranose (2α/2β), respectively. All these compounds were evaluated for antifouling activity against the settlement of Balanus amphitrite larvae, along with the cytotoxic effect against the proliferation of HeLa cell lines.

Catalytic reduction of 4-nitrophenol with gold nanoparticles synthesized by caffeic acid

In this study, various concentrations of caffeic acid (CA) were used to synthesize gold nanoparticles (CA-AuNPs) in order to evaluate their catalytic activity in the 4-nitrophenol reduction reaction. To facilitate catalytic activity, caffeic acid was removed by centrifugation after synthesizing CA-AuNPs. The catalytic activity of CA-AuNPs was compared with that of centrifuged CA-AuNPs (cf-CA-AuNPs). Notably, cf-CA-AuNPs exhibited up to 6.41-fold higher catalytic activity compared with CA-AuNPs. The catalytic activity was dependent on the caffeic acid concentration, and the lowest concentration (0.08 mM) produced CA-AuNPs with the highest catalytic activity. The catalytic activities of both CA-AuNPs and cf-CA-AuNPs decreased with increasing caffeic acid concentration. Furthermore, a conversion yield of 4-nitrophenol to 4-aminophenol in the reaction mixture was determined to be 99.8% using reverse-phase high-performance liquid chromatography. The product, 4-aminophenol, was purified from the reaction mixture, and its structure was confirmed by ¹H-NMR. It can be concluded that the removal of the reducing agent, caffeic acid in the present study, significantly enhanced the catalytic activity of CA-AuNPs in the 4-nitrophenol reduction reaction.

The genus Scrophularia: a source of iridoids and terpenoids with a diverse biological activity

CONTEXT

Scrophularia genus (Scrophulariaceae) includes about 350 species commonly known as figwort. Many species of this genus grow wild in nature and have not been cultivated yet. However, some species are in danger of extinction.

OBJECTIVE

This paper reviews the chemical compounds, biological activities and the ethnopharmacology of some Scrophularia species.

MATERIALS AND METHODS

All information was obtained through reported data on bibliographic database such as Scopus, United States National Agricultural Library, Biological Abstracts, EMBASE, PubMed, MedlinePlus, PubChem and Springer Link (1934-2017). The information in different Pharmacopoeias on this genus was also gathered from 1957 to 2007.

RESULTS

The structures of 204 compounds and their biological activity were presented in the manuscript: glycoside esters, iridoid glycosides and triterpenoids are the most common compounds in this genus. Among them, scropolioside like iridoids have shown potential for anti-inflammatory, hepatoprotective and wound healing activity. Among the less frequently isolated compounds, resin glycosides such as crypthophilic acids have shown potent antiprotozoal and antimicrobial activities.

CONCLUSION

The Scrophularia genus seems to be a rich source of iridoids and terpenoids, but isolation and identification of its alkaloids have been a neglected area of scientific study. The diverse chemical compounds and biological activities of this genus will motivate further investigation on Scrophularia genus as a source of new therapeutic medications.

Cinnamic Acid and Its Derivatives: Mechanisms for Prevention and Management of Diabetes and Its Complications

With recent insight into the development of dietary supplements and functional foods, search of effective phytochemical compounds and their mechanisms involved in prevention and management of diabetes and its complications are now being assessed. Cinnamic acid and its derivatives occur naturally in high levels of plant-based foods. Among various biological activities, cinnamic acid and its derivatives are associated with a beneficial influence on diabetes and its complications. The aim of the review is to summarize the potential mechanisms of these compounds for prevention and management of diabetes and its complications. Based on several in vitro studies and animal models, cinnamic acid and its derivatives act on different mechanism of actions, including stimulation of insulin secretion, improvement of pancreatic β-cell functionality, inhibition of hepatic gluconeogenesis, enhanced glucose uptake, increased insulin signaling pathway, delay of carbohydrate digestion and glucose absorption, and inhibition of protein glycation and insulin fibrillation. However, due to the limited intestinal absorption being a result of low bioavailability of cinnamic acid and its derivatives, current improvement efforts with entrapping into solid and liquid particles are highlighted. Further human clinical studies are needed to clarify the effects of cinnamic acid and its derivatives in diabetic patients.

Cinnamic acid shortens the period of the circadian clock in mice

Cinnamic acid (CA) derivatives have recently received focus due to their anticancer, antioxidant, and antidiabetic properties. The present study aimed to determine the effects of cinnamic acid on the circadian clock, which is a cell-autonomous endogenous system that generates circadian rhythms that govern the behavior and physiology of most organisms. Cinnamic acid significantly shortened the circadian period of PER2::LUC expression in neuronal cells that differentiated from neuronal progenitor cells derived from PER2::LUC mouse embryos. Cinnamic acid did not induce the transient mRNA expression of clock genes such as Per1 and Per2 in neuronal cells, but significantly shortened the half-life of PER2::LUC protein in neuronal cells incubated with actinomycin D, suggested that CA post-transcriptionally affects the molecular clock by decreasing Per2 mRNA stability. A continuous infusion of CA into mice via an Alzet osmotic pump under constant darkness significantly shortened the free-running period of wheel-running rhythms. These findings suggest that CA shortens the circadian period of the molecular clock in mammals.

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Cinnamic acid shortened the period of neuronal circadian expression of PER2::LUC.

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Cinnamic acid decreased Per2 mRNA stability in neuronal cells.

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Cinnamic acid shortened the free-running period of wheel-running rhythms in mice.

Natural products against Alzheimer's disease: Pharmaco-therapeutics and biotechnological interventions

Alzheimer's disease (AD) is a severe, chronic and progressive neurodegenerative disease associated with memory and cognition impairment ultimately leading to death. It is the commonest reason of dementia in elderly populations mostly affecting beyond the age of 65. The pathogenesis is indicated by accumulation of the amyloid-beta (Aβ) plaques and neurofibrillary tangles (NFT) in brain tissues and hyperphosphorylation of tau protein in neurons. The main cause is considered to be the formation of reactive oxygen species (ROS) due to oxidative stress. The current treatment provides only symptomatic relief by offering temporary palliative therapy which declines the rate of cognitive impairment associated with AD. Inhibition of the enzyme acetylcholinesterase (AChE) is considered as one of the major therapeutic strategies offering only symptomatic relief and moderate disease-modifying effect. Other non-cholinergic therapeutic approaches include antioxidant and vitamin therapy, stem cell therapy, hormonal therapy, use of antihypertensive or lipid-lowering medications and selective phosphodiesterase (PDE) inhibitors, inhibition of β-secretase and γ-secretase and Aβ aggregation, inhibition of tau hyperphosphorylation and intracellular NFT, use of nonsteroidal anti-inflammatory drugs (NSAIDs), transition metal chelators, insulin resistance drugs, etanercept, brain-derived neurotrophic factor (BDNF) etc. Medicinal plants have been reported for possible anti-AD activity in a number of preclinical and clinical trials. Ethnobotany, being popular in China and in the Far East and possibly less emphasized in Europe, plays a substantial role in the discovery of anti-AD agents from botanicals. Chinese Material Medica (CMM) involving Chinese medicinal plants has been used traditionally in China in the treatment of AD. Ayurveda has already provided numerous lead compounds in drug discovery and many of these are also undergoing clinical investigations. A number of medicinal plants either in their crude forms or as isolated compounds have exhibited to reduce the pathological features associated with AD. In this present review, an attempt has been made to elucidate the molecular mode of action of various plant extracts, phytochemicals and traditional herbal formulations investigated against AD as reported in various preclinical and clinical tests. Herbal synergism often found in polyherbal formulations were found effective to combat disease heterogeneity as found in complex pathogenesis of AD. Finally a note has been added to describe biotechnological improvement, genetic and genomic resources and mathematical and statistical techniques for empirical model building associated with anti-AD plant secondary metabolites and their source botanicals.

Naturally Occurring Cinnamic Acid Sugar Ester Derivatives

Cinnamic acid sugar ester derivatives (CASEDs) are a class of natural product with one or several phenylacrylic moieties linked with the non-anomeric carbon of a glycosyl skeleton part through ester bonds. Their notable anti-depressant and brains protective activities have made them a topic of great interest over the past several decades. In particular the compound 3′,6-disinapoylsucrose, the index component of Yuanzhi (a well-known Traditional Chinese Medicine or TCM), presents antidepressant effects at a molecular level, and has become a hotspot of research on new lead drug compounds. Several other similar cinnamic acid sugar ester derivatives are reported in traditional medicine as compounds to calm the nerves and display anti-depression and neuroprotective activity. Interestingly, more than one third of CASEDs are distributed in the family Polygalaceae. This overview discusses the isolation of cinnamic acid sugar ester derivatives from plants, together with a systematic discussion of their distribution, chemical structures and properties and pharmacological activities, with the hope of providing references for natural product researchers and draw attention to these interesting compounds.

Induction of apoptosis and G2 /M cell cycle arrest by Scrophularia striata in a human leukaemia cell line

OBJECTIVES

Scrophularia striata Boiss (Scrophulariaceae) is a plant that grows in northeastern Iran; it has been used traditionally to treat various inflammatory disorders. This study was designed to investigate cytotoxic effects of S. striata extract, on the Jurkat human leukaemia cell line (T-cell leukaemia).

MATERIALS AND METHODS

Phytochemical assay by thin layer chromatography and 2, 2 diphenyl-1-picryl-hydrazyl were used to evaluate main compounds and antioxidant capacity of the plant extract, respectively. Its inhibitory effect on Jurkat cells was evaluated by MTT assay. In addition, cell cycle distribution and apoptotic cell death were evaluated by propidium iodide and annexin V-FITC/ propidium iodide staining.

RESULTS

These showed that the main components present in S. striata extract included flavonoids, phenolic compounds and phenyl propanoids. Treatment with extract was significantly cytotoxic to the tumour cell line. In addition, flow cytometry analysis indicated that S. striata extract induced cell cycle arrest in G2 /M phase and apoptosis of tumour cells.

CONCLUSIONS

Results of the study indicated that S. striata extract could inhibit leukaemia cell proliferation by inducing G2 /M phase arrest and apoptosis.

Antioxidant and neuroprotective effects of Scrophularia striata extract against oxidative stress-induced neurotoxicity

In this study, the neuroprotective effect of Scrophularia striata Boiss (Scrophulariaceae) extract, a plant growing in northeastern of Iran, against oxidative stress-induced neurocytotoxicity in PC12 was evaluated. The PC12 cell line pretreated with different concentrations (10, 50, 100, and 200 μg/ml) of the extract and then treated with H2O2 to induce oxidative stress and neurotoxicity. Survival of the cells, reactive oxygen species (ROS) generation, and apoptosis were measured using MTT assay, fluorescent probe 2',7'-dichlorofluorescein diacetate, and annexin V/propidium iodide, respectively. Moreover, the 2,2-diphenyl-1-picryl-hydrazyl (DPPH) was used to evaluate the antioxidant capacity of the plant extract. Phytochemical assay by thin layer chromatography showed that the main components, including phenolic compounds, phenyl propanoids and flavonoids, were presented in the S. striata extract. The extract in concentrations of 50-200 μg/ml protected PC12 cells from H2O2-induced toxicity. The survival of the cells at concentration of 200 μg/ml was 64 % compared to that of H2O2 alone-treated cells (48 %) (p < 0.001). The extract also dose-dependently reduced intracellular ROS production (p < 0.001). Moreover, the extract showed antioxidative effects and decreased apoptotic cells. Collectively, these findings indicated the ability of S. striata to decrease ROS generation and cell apoptosis and also suggest the presence of the neuroprotective agents in this plant.

Current Evidence of Chinese Herbal Constituents with Effects on NMDA Receptor Blockade

NMDA receptor (NMDA-R) is an important molecular entity governing a wide range of functions in the central nervous system. For example, the NMDA-R is involved in memory and cognition, and impairment of both (as in Alzheimer's Disease) is attributed to NMDA-mediated neurotoxicity. With greater understanding of the NMDA-R structure, antagonists with varying degrees of binding-site and subtype selectivity have been developed and put into clinical use. Discovery of target-specific Chinese herbs have also been made in parallel. This article provides an overview of the known active sites on the NMDA-R, followed by a discussion of the relevant herbs and their constituents. Experimental evidence supporting the inhibitory role of the herbal compounds on the NMDA-R is highlighted. For some of the compounds, potential research directions are also proposed to further elucidate the underlying mechanisms of the herbs. It is envisaged that future investigations based on the present data will allow more clinically relevant herbs to be identified.

Protective effects of Scrophularia striata in Ovalbumin-induced mice asthma model

BACKGROUND

Scrophularia striata Boiss. (Scrophulariaceae) is a plant growing in the northeastern part of Iran and being used as a traditional herb for various inflammatory disorders.This study was designed to investigate the protective effects of the Scrophularia striata extract in Ovalbumin (OVA) induced-asthma mice model.

METHODS

OVA-sensitized mice were intrapritonealy treated with two doses (100 and 200 mg/kg) of the extract on days 8 to 14 separately. Broncoalveolar lavage fluids (BALF) was collected 48 h after the final OVA challenge and then the number of eosinophils and other inflammatory cells were assessed by direct microscopic counting. In addition, total immunoglubolin (Ig) E and OVA-specific IgE levels in serum, IL-4 and IL-5 cytokines in BALF were determined by Enzyme-Linked Immunosorbent Assay. Moreover, phytochemical assay by thin layer chromatography (TLC) and the 2, 2 diphenyl-1-picrylhydrazyl (DPPH) were used to evaluate the main compounds and the antioxidant capacity of the plant extract, respectively.

RESULTS

The results showed that the main components; including flavonoids, phenolic compounds and phenyl propanoids were presented in the S. striata extract. In addition, the treatment with extract significantly reduced the number of inflammatory cells and suppressed T-helper 2 (Th2) cytokines including IL-4 and IL-5 in BALF. Also, total IgE and OVA-specific IgE levels in the serum decreased.

CONCLUSION

Collectively, it is concluded that the extract has the potential to modulate the Th2 cytokines and could be used as immunomodulatory agent in the treatment of allergic asthma.

Inhibitory effects of adlay bran (Coix lachryma-jobi L. var. ma-yuen Stapf) on chemical mediator release and cytokine production in rat basophilic leukemia cells

ETHNOPHARMACOLOGICAL RELEVANCE

Adlay (Job's tears, Coix lachryma-jobi L. var. ma-yuen Stapf) has long been used in China to treat rheumatism.

AIM OF THE STUDY

We investigated the anti-allergic effects of adlay bran on rat basophilic leukemia (RBL)-2H3 cells.

MATERIALS AND METHODS

To evaluate the anti-allergic effects of adlay bran, the release of histamines and cytokines were measured using ELISA. To explore the mechanism of these effects, the protein expression levels were determined using western blotting.

RESULTS

A 40.8μg/mL concentration of the ethyl acetate fraction of the ethanolic extracts of adlay bran (ABE-EtOAc) effectively inhibited mast cell degranulation. The 40-100% EtOAc/Hex subfractions of ABE-EtOAc inhibited histamine release with an IC(50) of 71-87μg/mL. Moreover, the ABE-EtOAc subfractions suppressed the secretion of interleukin (IL)-4, IL-6 and tumor necrosis factor-α in the RBL-2H3 cells, indicating that adlay bran can inhibit cytokine secretion in the late phase of the allergic reaction. In addition, adlay bran reduced the intracellular production of reactive oxygen species, inhibited the phosphorylation of Akt and decreased the expression of protein kinase C. Furthermore, six phenolic acids and one flavone were isolated. Of these compounds, luteolin showed the most potent inhibitory activity (IC(50)=1.5μg/mL).

CONCLUSION

Adlay bran extract reduced the release of histamines and cytokines and suppressed the production of Akt. These combined effects influenced the signal transduction in RBL-2H3 cells, thereby revealing the mechanisms of the anti-allergic effects of adlay.

Anti-inflammatory Activity of 1-docosanoyl Cafferate Isolated from Rhus verniciflua in LPS-stimulated BV2 Microglial Cells

Although various derivatives of caffeic acid have been reported to possess a wide variety of biological activities such as protection of neuronal cells against excitotoxicity, the biological activity of 1-docosanoyl cafferate (DC) has not been examined. The objective of the present study was to evaluate the anti-inflammatory effects of DC, isolated from the stem bark of Rhus verniciflua, on lipopolysaccharide (LPS)-stimulated BV2 microglial cells. Pretreatment of cells with DC significantly attenuated LPS-induced NO production, and mRNA and protein expression of iNOS in a concentration-dependent manner. DC also significantly suppressed LPS-induced release of cytokines such as TNF-α and IL-1β . Consistent with the decrease in cytokine release, DC dose-dependently and significantly attenuated LPS-induced mRNA expression of these cytokines. Furthermore, DC significantly suppressed LPS-induced degradation of IKB, which retains NF-kB in the cytoplasm. Therefore, nuclear translocation of NF-kB induced by LPS stimulation was significantly suppressed with DC pretreatment. Taken together, the present study suggests that DC exerts its anti-inflammatory activity through the suppression of NF-kB translocation to the nucleus.

Ferulic acid protects against carbon tetrachloride-induced liver injury in mice

Ferulic acid (FA), isolated from the root of Scrophularia buergeriana, is a phenolic compound possessing antioxidant, anticancer, and antiinflammatory activities. Here, we have investigated the hepatoprotective effect of FA against carbon tetrachloride (CCl(4))-induced acute liver injury. Mice were treated intraperitoneally with vehicle or FA (20, 40, and 80mg/kg) 1h before and 2h after CCl(4) (20μl/kg) injection. The serum activities of aminotransferases and the hepatic level of malondialdehyde were significantly higher after CCl(4) treatment, while the concentration of reduced glutathione was lower. These changes were attenuated by FA. The serum level and mRNA expression of tumor necrosis factor-α significantly increased after CCl(4) treatment, and FA attenuated these increases. The levels of inducible nitric oxide synthase and cyclooxygenase-2 protein and mRNA expression after CCl(4) treatment were significantly higher and FA reduced these increases. CCl(4)-treated mice showed increased nuclear translocation of nuclear factor-κB (NF-κB), and decreased levels of inhibitors of NF-κB in cytosol. Also, CCl(4) significantly increased the level of phosphorylated JNK and p38 mitogen-activated protein (MAP) kinase, and nuclear translocation of activated c-Jun. FA significantly attenuated these changes. We also found that acute CCl(4) challenge induced TLR4, TLR2, and TLR9 protein and mRNA expression, and FA significantly inhibited TLR4 expression. These results suggest that FA protects from CCl(4)-induced acute liver injury through reduction of oxidative damage and inflammatory signaling pathways.

Pharmacological induction of neuroglobin expression

Neuroglobin (Ngb) is an intracellular, oxygen-binding neuronal protein with protective effects against ischemia and related pathological processes. To identify small molecules capable of inducing Ngb protein expression, which might have therapeutic benefit, we examined Ngb expression by Western blot in cultured HN33 (mouse hippocampal neuron x N18TG2 neuroblastoma) cells. In addition to deferoxamine, which was shown previously to enhance Ngb levels, Ngb expression was increased by the short-chain fatty acids cinnamic acid and valproic acid (≥ 100 μmol/l), but not by other short-chain fatty acids, histone deacetylase inhibitors, or anticonvulsants. Drugs that stimulate the expression of neuroprotective proteins like Ngb may have therapeutic potential in the treatment of stroke and other neurological disorders.

E-p-methoxycinnamic acid production in hairy root cultures of Scrophularia buergeriana Miquel

E-p-methoxycinnamic acid (MCA) is one of the main active constituents of Scrophularia buergeriana Miquel and has hepatoprotective, anti-amnestic, and neuroprotective activities. For studying in vitro production of MCA, we established a hairy root culture of S. buergeriana by infecting leaf explants with Agrobacterium rhizogenes R1000, and tested the growth and MCA production of these cultures using different strengths of media and concentrations of auxins. Hairy roots grown in half-strength MS medium showed the highest levels of growth (10.3 g/l) as well as MCA production (0.83 mg/100 g dry weight). Hairy root culture with the treatment of 0.5 mg/l IBA produced the highest amount of dry weight (11.8 g/l) and MCA (1.26 mg/100 g dry weight) production. These results demonstrate that the hairy root culture of S. buergeriana is a valuable alternative approach for the production of MCA. .