Neuroprotective effects of phytochemicals on dopaminergic neuron cultures

Emerging Role of Plant-Based Bioactive Compounds as Therapeutics in Parkinson's Disease

Neurological ailments, including stroke, Alzheimer's disease (AD), epilepsy, Parkinson's disease (PD), and other related diseases, have affected around 1 billion people globally to date. PD stands second among the common neurodegenerative diseases caused as a result of dopaminergic neuron loss in the midbrain's substantia nigra regions. It affects cognitive and motor activities, resulting in tremors during rest, slow movement, and muscle stiffness. There are various traditional approaches for the management of PD, but they provide only symptomatic relief. Thus, a survey for finding new biomolecules or substances exhibiting the therapeutic potential to patients with PD is the main focus of present-day research. Medicinal plants, herbal formulations, and natural bioactive molecules have been gaining much more attention in recent years as synthetic molecules orchestrate a number of undesired effects. Several in vitro, in vivo, and in silico studies in the recent past have demonstrated the therapeutic potential of medicinal plants, herbal formulations, and plant-based bioactives. Among the plant-based bioactives, polyphenols, terpenes, and alkaloids are of particular interest due to their potent anti-inflammatory, antioxidant, and brain-health-promoting properties. Further, there are no concise, elaborated articles comprising updated mechanism-of-action-based reviews of the published literature on potent, recently investigated (2019-2023) medicinal plants, herbal formulations, and plant based-bioactive molecules, including polyphenols, terpenes, and alkaloids, as a method for the management of PD. Therefore, we designed the current review to provide an illustration of the efficacious role of various medicinal plants, herbal formulations, and bioactives (polyphenols, terpenes, and alkaloids) that can become potential therapeutics against PD with greater specificity, target approachability, bioavailability, and safety to the host. This information can be further utilized in the future to develop several value-added formulations and nutraceutical products to achieve the desired safety and efficacy for the management of PD.

Carving the senescent phenotype by the chemical reactivity of catecholamines: An integrative review

Macromolecules damaged by covalent modifications produced by chemically reactive metabolites accumulate in the slowly renewable components of living bodies and compromise their functions. Among such metabolites, catecholamines (CA) are unique, compared with the ubiquitous oxygen, ROS, glucose and methylglyoxal, in that their high chemical reactivity is confined to a limited set of cell types, including the dopaminergic and noradrenergic neurons and their direct targets, which suffer from CA propensities for autoxidation yielding toxic quinones, and for Pictet-Spengler reactions with carbonyl-containing compounds, which yield mitochondrial toxins. The functions progressively compromised because of that include motor performance, cognition, reward-driven behaviors, emotional tuning, and the neuroendocrine control of reproduction. The phenotypic manifestations of the resulting disorders culminate in such conditions as Parkinson's and Alzheimer's diseases, hypertension, sarcopenia, and menopause. The reasons to suspect that CA play some special role in aging accumulated since early 1970-ies. Published reviews address the role of CA hazardousness in the development of specific aging-associated diseases. The present integrative review explores how the bizarre discrepancy between CA hazardousness and biological importance could have emerged in evolution, how much does the chemical reactivity of CA contribute to the senescent phenotype in mammals, and what can be done with it.

Do Naturally Occurring Antioxidants Protect Against Neurodegeneration of the Dopaminergic System? A Systematic Revision in Animal Models of Parkinson's Disease

Parkinson's disease (PD) is the second most common neurodegenerative disease and is characterized by a significant decrease in dopamine levels, caused by progressive degeneration of the dopaminergic neurons in the nigrostriatal pathway. Multiple mechanisms have been implicated in its pathogenesis, including oxidative stress, neuroinflammation, protein aggregation, mitochondrial dysfunction, insufficient support for neurotrophic factors and cell apoptosis. The absence of treatments capable of slowing or stopping the progression of PD has increased the interest in the natural antioxidant substances present in the diet, since they have multiple beneficial properties and it is possible that they can influence the mechanisms responsible for the dysfunction and death of dopaminergic neurons. Thus, the purpose of this systematic review is to analyze the results obtained in a set of studies carried out in the last years, which describe the neuroprotective, antioxidant and regenerative functions of some naturally occurring antioxidants in experimental models of PD. The results show that the exogenous no enzymatic antioxidants can significantly modify the biochemical and behavioral mechanisms that contribute to the pathophysiology of Parkinsonism in experimental animals. Therefore, it is possible that they may contribute to effective neuroprotection by providing a significant improvement in neuropathological markers. In conclusion, the results of this review suggest that exogenous antioxidants can be promising therapeutic candidates for the prevention and treatment of PD.

Metabolism of Du Zhong Formula in rats using UPLC-Q-TOF/MS

Du Zhong Formula (DZF), a traditional Chinese medicine formula derived from BeiJiQianJinYaoFang, is used to treat kidney deficiency and lumbago. In this study, ultra-high-performance liquid chromatography quadrupole time-of-flight mass spectrometer (UPLC-Q-TOF/MS) technique combined with pattern recognition analysis was applied for analysis of metabolic profiles of the bioactive components of the DZF in rat biological samples. In this experiment, a total of 73 compounds, including 53 prototype components and 20 metabolites, were identified tentatively in vivo compared with blank urine, plasma, feces, and cerebrospinal fluid (CSF). The prototype ingredients in DZF include terpenoids, gingerols, phenylpropanoids, alkaloids, phenanthrenes, bibenzyls, organic acids, and other ingredients. The metabolic pathways of DZF involved reduction, demethylation, hydroxylation, desugarization, deoxygenation, glucuronidation, sulfation, and methylation. The proposed method could develop an integrated template approach to analyze screening and identification of the bioactive components in plasma, urine, feces, and CSF after oral administration of herb medicines. Additionally, this investigation might provide helpful chemical information for further pharmacology and activity mechanism of DZF.

Curcumin-Coumarin Hybrid Analogues as Multitarget Agents in Neurodegenerative Disorders

Neurodegenerative diseases have a complex nature which highlights the need for multitarget ligands to address the complementary pathways involved in these diseases. Over the last decade, many innovative curcumin-based compounds have been designed and synthesized, searching for new derivatives having anti-amyloidogenic, inhibitory of tau formation, as well as anti-neuroinflammation, antioxidative, and AChE inhibitory activities. Regarding our experience studying 3-substituted coumarins with interesting properties for neurodegenerative diseases, our aim was to synthesize a new series of curcumin–coumarin hybrid analogues and evaluate their activity. Most of the 3-(7-phenyl-3,5-dioxohepta-1,6-dien-1-yl)coumarin derivatives 11–18 resulted in moderated inhibitors of hMAO isoforms and AChE and BuChE activity. Some of them are also capable of scavenger the free radical DPPH. Furthermore, compounds 14 and 16 showed neuroprotective activity against H₂O₂ in SH-SY5Y cell line. Nanoparticles formulation of these derivatives improved this property increasing the neuroprotective activity to the nanomolar range. Results suggest that by modulating the substitution pattern on both coumarin moiety and phenyl ring, ChE and MAO-targeted derivatives or derivatives with activity in cell-based phenotypic assays can be obtained.

Effects of Pretreatment With Ginseng Extract on Dopamine D2 Receptor Analgesia

Introduction:

The ginseng extract is an herb that has been used for many purposes such as analgesic effect. Dopamine D2 receptors are involved in the regulation of pain in humans. Therefore, the present investigation aims to study how pretreatment with aqueous-alcoholic extract of ginseng can affect dopamine D2 receptors’ pain sensitivity.

Methods:

We used 45 adult male rats weighing 250±20 for this study. Animals were maintained in a standard condition at a temperature of 21°C–24°C. The experimental groups were as follows: 1. Sham 1 (intraperitoneal [IP] injection of normal saline); 2. Sham 2 (intracerebroventricular [ICV] injection of artificial cerebrospinal fluid [ACSF]); 3. Experimental 1 (IP injection of ginseng extract); 4 and 5. Experimental groups 2 and 3 (IP injection of ginseng extract + bromocriptine 10 and 30 μg/rat by ICV injection); 6 and 7) experimental groups 4 and 5 (IP injection of ginseng extract + chlorpromazine 20 and 40 μg/rat by ICV injection). Ginseng extract 100 mg/kg/d was used for 7 days. Pain sensitivity test was done in all groups with the formalin test. Lateral ventricles of the rats were cannulated unilaterally by the stereotaxic procedure.

Results:

Our data showed that ginseng (100 mg/kg/d) significantly (P<0.05) decreased pain sensitivity compared to the sham 1 group. Bromocriptine in two doses significantly decreased pain sensitivity compared to the sham 2 group. Chlorpromazine in high doses significantly increased pain sensitivity compared to the sham 2 group.

Conclusion:

The present results indicate that ginseng can modulate the D2 receptor of the dopamine system in the control of pain sensitivity in the formalin test. Because bromocriptine and ginseng have similar effects, it seems that they had synergistic effects.

Encapsulation of curcumin into layered double hydroxides improve their anticancer and antiparasitic activity

Objectives

Curcumin (CUR) has well-known activity against cancer cells and parasites; however, its applications are limited since this is an unstable molecule, which may suffer degradation by light and temperature, also, the low water solubility reduce its bioavailability. Layered double hydroxides (LDH) are well-known materials owing to the excellent anion exchange capacity, good biocompatibility and low toxicity.

Methods

Layered double hydroxides nanoparticles prepared with zinc and magnesium cations were used as a vehicle for CUR in Caco-2, Giardia lamblia and Entamoeba histolytica cultures. The physicochemical properties of Mg-LDH-CUR and Zn-LDH-CUR were characterized by scanning electron microscopy (SEM), Fourier transform infrared spectrometry (FTIR) and X-ray powder diffraction (XRD). Additionally, the load efficiency, release profiles and photostability of CUR were quantified by high-performance liquid chromatography (HPLC) and UV-Vis spectrometry. Then, Mg-LDH-CUR and Zn-LDH-CUR were tested on Caco-2, G. lamblia and E. histolytica cultures.

Key findings

The experiments demonstrated that Zn-LDH-CUR protects better against photodegradation by UV light, while Mg-LDH-CUR showed increased toxicity against Caco-2 cell, G. lamblia and E. histolytica, in comparison with free CUR.

Conclusions

Layered double hydroxides are good vehicles to improve stability, resistance to degradation of CUR, also they are useful to improve solubility, provide a controlled release and improve the cytotoxic activity. Additionally, it was shown that the composition of the M+2 cation of LDH affects its properties and structure and that this directly influences its biological activity. The findings are important to select the composition of the encapsulation vehicle for a specific activity.

Discrimination of Different Species of Dendrobium with an Electronic Nose Using Aggregated Conformal Predictor

A method using electronic nose to discriminate 10 different species of dendrobium, which is a kind of precious herb with medicinal application, was developed with high efficiency and low cost. A framework named aggregated conformal prediction was applied to make predictions with accuracy and reliability for E-nose detection. This method achieved a classification accuracy close to 80% with an average improvement of 6.2% when compared with the results obtained by using traditional inductive conformal prediction. It also provided reliability assessment to show more comprehensive information for each prediction. Meanwhile, two main indicators of conformal predictor, validity and efficiency, were also compared and discussed in this work. The result shows that the approach integrating electronic nose with aggregated conformal prediction to classify the species of dendrobium with reliability and validity is promising.

The medicinal and pharmaceutical importance of Dendrobium species

Plants of the Dendrobium genus, one of the largest in the Orchidaceae, manifest a diversity of medicinal effects encompassing antiangiogenic, immunomodulating, antidiabetic, cataractogenesis-inhibiting, neuroprotective, hepatoprotective, anti-inflammatory, antiplatelet aggregation, antifungal, antibacterial, antiherpetic, antimalarial, aquaporin-5 stimulating, and hemagglutininating activities and also exert beneficial actions on colonic health and alleviate symptoms of hyperthyroidism. The active principles include a wide range of proteinaceous and non-proteinaceous molecules. This mini-review discusses the latest advances in what is known about the medicinal and pharmaceutical properties of members of the Dendrobium genus and explores how biotechnology can serve as a conduit to mass propagate valuable germplasm for sustainable exploration for the pharmaceutical industry.