Chelating and antioxidant properties of l-Dopa containing tetrapeptide for the treatment of neurodegenerative diseases

Recent Advances in Targeting Transition Metals (Copper, Iron, and Zinc) in Alzheimer's Disease

Changes in the transition metal homeostasis in the brain are closely linked with Alzheimer's disease (AD), including intraneuronal iron accumulation and extracellular copper and zinc pooling in the amyloid plague. The brain copper, zinc, and iron surplus are commonly acknowledged characteristics of AD, despite disagreements among some. This has led to the theory that oxidative stress resulting from abnormal homeostasis of these transition metals may be a causative explanation behind AD. In the nervous system, the interaction of metals with proteins appears to be an essential variable in the development or suppression of neurodegeneration. Chelation treatment may be an option for treating neurodegeneration induced by transition metal ion dyshomeostasis. Some clinicians even recommend using chelating agents as an adjunct therapy for AD. The current review also looks at the therapeutic strategies that have been attempted, primarily with metal-chelating drugs. Metal buildup in the nervous system, as reported in the AD, could be the result of compensatory mechanisms designed to improve metal availability for physiological functions.

Prevention of seminal vesicle damage by Mucuna pruriens var. pruriens seed extract in chronic unpredictable mild stress mice

CONTEXT

Thai Mucuna pruriens (L.) DC. var. pruriens (Fabaceae) or T-MP seed extract has been shown to improve sexual performance and sperm quality.

OBJECTIVE

This study investigates the preventive effects of T-MP against seminal vesicle damage, apoptotic and Nrf2 protein expression in mice under chronic unpredictable mild stress (CUMS).

MATERIALS AND METHODS

Forty-eight male ICR mice were divided into four groups: control, CUMS, T-MP300 + CUMS and T-MP600 + CUMS. Mice in control and CUMS groups received distilled water, while those in treated groups were pretreated with T-MP extract (300 or 600 mg/kg BW) for 14 consecutive days. The CMUS and co-treated groups were exposed to one random stressor (of 12 total) each day for 43 days. Components and histopathology of the seminal vesicle were examined, along with localization of androgen receptor (AR) and caspase 3. Expression of seminal AR, tyrosine phosphorylated (TyrPho), heat shock protein 70 (Hsp70), caspases (3 and 9) and nuclear factor erythroid 2-related factor 2 (Nrf2) proteins was investigated.

RESULTS

T-MP extract at a dose of 600 mg/kg BW improved seminal epithelial damage and secretion of fluid containing essential substances and proteins in CUMS mice. It also increased the expression of AR and TyrPho proteins. Additionally, T-MP increased expression of Nrf2 and inhibited seminal vesicular apoptosis through the suppression of Hsp70 and caspase expression.

CONCLUSION

T-MP seeds have an antiapoptotic property in chronic stress seminal vesicle. It is possible to apply this extract for the enhancement of seminal plasma quality.

Protective effects of Thai Mucuna pruriens (L.) DC. var. pruriens seeds on sexual behaviors and essential reproductive markers in chronic unpredictable mild stress mice

Background and aims

Chronic stress is a major common cause of male infertility. Many species of velvet beans are shown to be rich in l-DOPA. In Thai folklore medicine, seeds of Mucuna pruriens (L.) DC. var. pruriens (Thai Mhamui or T-MP) have been used for treating erectile dysfunction. This study aimed to determine l-DOPA levels in T-MP seed extract and investigate its preventive on sexual behaviors and reproductive parameter damages including essential proteins in chronic unpredictable mild stress (CUMS) mice.

Experimental procedure

Mice were divided into 4 groups: (I) control, (II) CUMS, (III) T-MP300 + CUMS, and (IV) T-MP600 + CUMS. Groups I and II received DW while groups III and IV were pretreated with the seed extracts (300 and 600 mg/kg BW) for 14 consecutive days before co-treatment with a randomly different CUMS/day (from 12 mild stressors) for 43 days.

Results and conclusion

T-MP seed extract contained l-DOPA approximately 10% of total dried weight. A dose of 600 mg/kg improved sexual performances and degenerative seminiferous epithelium in CUMS mice. Sperm qualities and testosterone level were elevated while corticosterone was decreased in co-treatment groups. T-MP-CUMS cotreated groups also improved expressions of AKAP4, AR, and TyrPho proteins in testis, epididymis, and sperm. T-MP increased StAR and CYP11A1 expressions in testis. It also suppressed testicular apoptosis via decreased expressions of Hsp70, caspases 3, and 9. T-MP seeds containing l-DOPA could improve sexual behaviors and essential reproductive proteins caused by CUMS.

Section

Natural Products.

Taxonomy classification by evise

Traditional Herbal Medicine; Animal Model; Histopathology.

Neuropeptides: Roles and Activities as Metal Chelators in Neurodegenerative Diseases

Neurodegenerative diseases, such as Alzheimer's disease (AD) and Parkinson's disease (PD), are characterized by deposits of amyloid proteins. The homeostasis of metal ions is crucial for the normal biological functions in the brain. However, in AD and PD, the imbalance of metal ions leads to formation of amyloid deposits. In the past four decades, there has been extensive effort to design compound agents than can chelate metal ions with the aim of preventing the formation of the amyloid deposits. Unfortunately, the compounds to date that were designed were not successful candidates to be used in clinical trials. Neuropeptides are small molecules that are produced and released by neurons. It has been shown that neuropeptides have neuroprotective effects in the brain and reduce the formation of amyloid deposits. This Review Article is focused on the function of neuropeptides as metal chelators. Experimental and computational studies demonstrated that neuropeptides could bind metal ions, such as Cu²⁺ and Zn²⁺. This Review Article provides perspectives and initiates future studies to investigate the role of neuropeptides as metal chelators in neurodegenerative diseases.

Anti-Migratory Effects of 4'-Geranyloxyferulic Acid on LPS-Stimulated U937 and HCT116 Cells via MMP-9 Down-Regulation: Involvement of ROS/ERK Signaling Pathway

Matrix metalloproteinases (MMPs) play a crucial role in tumor angiogenesis, and metastasis. 4'-geranyloxyferulic acid (GOFA) has anti-tumor and anti-inflammatory proprieties. Herein, we aimed to determine whether this compound affects cell survival, invasion, and migration through reactive oxygen species (ROS)-mediated MMPs activation of extracellular signal-regulated kinases (ERKs) and p38 signaling in lymphocytic histiocytoma (U937) and colorectal cancer (HCT116) cells. We observed that lipopolysaccharide (LPS) stimulated U937 and HCT116 cells presented abnormal cell proliferation and increased metalloproteinase (MMP-9) activity and expression. Non-cytotoxic doses of GOFA blunted matrix invasive potential by reducing LPS-induced MMP-9 expression and cell migration via inhibiting ROS/ ERK pathway. GOFA also attenuated apoptosis and cell senescence. Our findings indicate that GOFA, inhibiting cancer cell proliferation and migration, could be therapeutically beneficial to prevent tumor metastasis.

The role of selected antioxidants in the development and treatment of Parkinson’s disease

The widespread aging of societies results in the intensification of the development of neurodegenerative diseases associated with advanced age, including Parkinson’s disease. Unfortunately, modern medicine is not able to unequivocally determine the etiopathogenesis of the disease, which is why no causative treatment can be given. According to the current state of knowledge, in the course of Parkinson’s disease the substantia nigra pars compacta in the midbrain degenerates, leading to a decrease in dopamine levels in the patient’s brain. This results in neurotransmission disturbances and the development of undesirable effects. Neurodegenerative changes are supposedly caused by the combination of various factors, including genetic factors, chronic inflammation, the interaction of toxins, disturbances in protein metabolism, and oxidative stress. The therapeutic possibilities associated with the administration of antioxidants, which could alleviate increased oxidative stress and contribute to the better quality of life of the patient, are considered. Taking into account the studies on numerous antioxidants, such as coenzyme Q10, B vitamins, vitamin D, vitamin E and resveratrol, it cannot be unequivocally stated that this is an effective treatment, because experiments carried out on both humans and animals gave conflicting results. It is reasonable to say that antioxidant deficiencies should be avoided and the physiological levels should be sought, as this may be translated into significant health benefits.

Modulation of Apoptotic Cell Death and Neuroprotective Effects of Glutathione-L-Dopa Codrug Against H2O2-Induced Cellular Toxicity

The L-3,4-dihydroxyphenylalanine (LD) is the gold standard drug currently used to manage Parkinson’s disease (PD) and to control its symptoms. However, LD could cause disease neurotoxicity due to the generation of pro-oxidant intermediates deriving from its autoxidation. In order to overcome this limitation, we have conjugated LD to the natural antioxidant glutathione (GSH) to form a codrug (GSH-LD). Here we investigated the effect of GSH-LD on H₂O₂-induced cellular toxicity in undifferentiated and differentiated lymphoma U-937 and dopaminergic neuroblastoma SH-SY5Y cell lines, used respectively as models to study the involvement of macrophages/microglia and dopaminergic neurons in PD. We analyzed the effect of GSH-LD on apoptosis and cellular oxidative stress, both considered strategic targets for the prevention and treatment of neurodegenerative diseases. Compared to LD and GSH, GSH-LD had a stronger effect in preventing hydrogen peroxide (H₂O₂) induced apoptosis in both cell lines. Moreover, GSH-LD was able to preserve cell viability, cellular redox status, gluthation metabolism and prevent reactive oxygen species (ROS) formation, in a phosphinositide 3-kinase (PI3K)/kinase B (Akt)-dependent manner, in a neurotoxicity cellular model. Our findings indicate that the GSH-LD codrug offers advantages deriving from the additive effect of LD and GSH and it could represent a promising candidate for PD treatment.

Metal Chelation Therapy and Parkinson's Disease: A Critical Review on the Thermodynamics of Complex Formation between Relevant Metal Ions and Promising or Established Drugs

The present review reports a list of approximately 800 compounds which have been used, tested or proposed for Parkinson’s disease (PD) therapy in the year range 2014–2019 (April): name(s), chemical structure and references are given. Among these compounds, approximately 250 have possible or established metal-chelating properties towards Cu(II), Cu(I), Fe(III), Fe(II), Mn(II), and Zn(II), which are considered to be involved in metal dyshomeostasis during PD. Speciation information regarding the complexes formed by these ions and the 250 compounds has been collected or, if not experimentally available, has been estimated from similar molecules. Stoichiometries and stability constants of the complexes have been reported; values of the cologarithm of the concentration of free metal ion at equilibrium (pM), and of the dissociation constant K_d (both computed at pH = 7.4 and at total metal and ligand concentrations of 10⁻⁶ and 10⁻⁵ mol/L, respectively), charge and stoichiometry of the most abundant metal–ligand complexes existing at physiological conditions, have been obtained. A rigorous definition of the reported amounts is given, the possible usefulness of this data is described, and the need to characterize the metal–ligand speciation of PD drugs is underlined.