SK-PC-B70M confers anti-oxidant activity and reduces Aβ levels in the brain of Tg2576 mice

Recent Advances in the Synthesis of Antioxidant Derivatives: Pharmacological Insights for Neurological Disorders

Neurological disorders, characterized by oxidative stress (OS) and inflammation, have become a major global health concern. Redox reactions play a vital role in regulating the balance of the neuronal microenvironment. Specifically, the imbalance leads to a significant weakening of the organism's natural defensive mechanisms. This, in turn, causes the development of harmful oxidative stress, which plays a crucial role in the onset and progression of neurodegenerative diseases. The quest for effective therapeutic agents has led to significant advancements in the synthesis of antioxidant derivatives. This review provides a comprehensive overview of the recent developments in the use of novel antioxidant compounds with potential pharmacological applications in the management of neurological disorders. The discussed compounds encompass a diverse range of chemical structures, including polyphenols, vitamins, flavonoids, and hybrid molecules, highlighting their varied mechanisms of action. This review also focuses on the mechanism of oxidative stress in developing neurodegenerative disease. The neuroprotective effects of these antioxidant derivatives are explored in the context of specific neurological disorders, including Alzheimer's disease, Parkinson's disease, and Huntington's disease. The ultimate goal is to provide effective treatments for these debilitating conditions and improve the quality of life for patients.

A review of structural modification and biological activities of oleanolic acid

Oleanolic acid (OA), a pentacyclic triterpenoid, exhibits a broad spectrum of biological activities, including antitumor, antiviral, antibacterial, anti-inflammatory, hepatoprotective, hypoglycemic, and hypolipidemic effects. Since its initial isolation and identification, numerous studies have reported on the structural modifications and pharmacological activities of OA and its derivatives. Despite this, there has been a dearth of comprehensive reviews in the past two decades, leading to challenges in subsequent research on OA. Based on the main biological activities of OA, this paper comprehensively summarized the modification strategies and structure-activity relationships (SARs) of OA and its derivatives to provide valuable reference for future investigations into OA.

Therapeutic Candidates for Alzheimer's Disease: Saponins

Drug development for Alzheimer's disease, the leading cause of dementia, has been a long-standing challenge. Saponins, which are steroid or triterpenoid glycosides with various pharmacological activities, have displayed therapeutic potential in treating Alzheimer's disease. In a comprehensive review of the literature from May 2007 to May 2023, we identified 63 references involving 40 different types of saponins that have been studied for their effects on Alzheimer's disease. These studies suggest that saponins have the potential to ameliorate Alzheimer's disease by reducing amyloid beta peptide deposition, inhibiting tau phosphorylation, modulating oxidative stress, reducing inflammation, and antiapoptosis. Most intriguingly, ginsenoside Rg1 and pseudoginsenoside-F11 possess these important pharmacological properties and show the best promise for the treatment of Alzheimer's disease. This review provides a summary and classification of common saponins that have been studied for their therapeutic potential in Alzheimer's disease, showcasing their underlying mechanisms. This highlights the promising potential of saponins for the treatment of Alzheimer's disease.

Pharmacological activities and molecular mechanisms of Pulsatilla saponins

Saponins are found in a variety of higher plants and display a wide range of pharmacological activities, including expectorant, anti-inflammatory, vasoprotective and antimicrobial properties. Pulsatilla chinensis (P. chinensis, Bai Tou Weng, ) has been used medically in China for thousands of years for the treatment of diseases caused by bacteria, and it is rich in triterpenoid saponins. In recent decades, anemoside B4 (Pulchinenoside C) is well studied since it has been used as a quality control marker for P. chinensis. At the same time, more and more other active compounds were found in the genus of Pulsatilla. In this review, we summarize the pharmacological activities of Pulsatilla saponins (PS) and discuss the cellular or molecular mechanisms that mediate their multiple activities, such as inducing cancer cell apoptosis, inhibiting tumor angiogenesis, and protecting organs via anti-inflammatory and antioxidant measures. We aim to provide comprehensive analysis and summary of research progress and future prospects in this field to facilitate further study and drug discovery of PS.

Antioxidants in Alzheimer's Disease: Current Therapeutic Significance and Future Prospects

Alzheimer's disease (AD) rate is accelerating with the increasing aging of the world's population. The World Health Organization (WHO) stated AD as a global health priority. According to the WHO report, around 82 million people in 2030 and 152 million in 2050 will develop dementia (AD contributes 60% to 70% of cases), considering the current scenario. AD is the most common neurodegenerative disease, intensifying impairments in cognition, behavior, and memory. Histopathological AD variations include extracellular senile plaques' formation, tangling of intracellular neurofibrils, and synaptic and neuronal loss in the brain. Multiple evidence directly indicates that oxidative stress participates in an early phase of AD before cytopathology. Moreover, oxidative stress is induced by almost all misfolded protein lumps like α-synuclein, amyloid-β, and others. Oxidative stress plays a crucial role in activating and causing various cell signaling pathways that result in lesion formations of toxic substances, which foster the development of the disease. Antioxidants are widely preferred to combat oxidative stress, and those derived from natural sources, which are often incorporated into dietary habits, can play an important role in delaying the onset as well as reducing the progression of AD. However, this approach has not been extensively explored yet. Moreover, there has been growing evidence that a combination of antioxidants in conjugation with a nutrient-rich diet might be more effective in tackling AD pathogenesis. Thus, considering the above-stated fact, this comprehensive review aims to elaborate the basics of AD and antioxidants, including the vitality of antioxidants in AD. Moreover, this review may help researchers to develop effectively and potentially improved antioxidant therapeutic strategies for this disease as it also deals with the clinical trials in the stated field.

Phytotherapeutics Against Alzheimer's Disease: Mechanism, Molecular Targets and Challenges for Drug Development

Alzheimer's disease is inflating worldwide and is combatted by only a few approved drugs. At best, these drugs treat symptomatic conditions by targeting cholinesterase and N-methyl-D-aspartate receptors. Most of the clinical trials in progress are focused to develop disease-modifying agents that aim single targets. The 'one drug-one target' approach is failing in the case of Alzheimer's disease due to its labyrinth etiopathogenesis. Traditional medicinal systems like ayurveda uses a holistic approach encompassing legion of medicinal plants exhibiting multimodal activity. Recent advances in high-throughput technologies have catapulted the research in the arena of ayurveda, specifically in identifying plants with potent anti-Alzheimer's disease properties and their phytochemical characterization. Nonetheless, clinical trials of very few herbal medicines are in progress. This review is a compendium of Indian plants and ayurvedic medicines against Alzheimer's disease and their paraphernalia. A record of 230 plants that are found in India with anti-Alzheimer's disease potential and about 500 phytochemicals from medicinal plants has been solicited with the hope of exploring the unexplored. Further, the molecular targets of phytochemicals isolated from commonly used medicinal plants such as Acorus calamus, Bacopa monnieri, Convolvulus pluricaulis, Tinospora cordifolia and Withania somnifera have been reviewed with respect to their multidimensional property such as antioxidant, anti-inflammation, anti-aggregation, synaptic plasticity modulation, cognition and memory enhancing activity. In addition, the strengths, and challenges in ayurvedic medicine that limit its use as mainstream therapy is discussed and a framework for the development of herbal medicine has been proposed.

Overview and Current Status of Alzheimer's Disease in Bangladesh

Alzheimer’s disease (AD) is a complex neurological disorder with economic, social, and medical burdens which is acknowledged as leading cause of dementia marked by the accumulation and aggregation of amyloid-β peptide and phosphorylated tau (p-tau) protein and concomitant dementia, neuron loss and brain atrophy. AD is the most prevalent neurodegenerative brain disorder with sporadic etiology, except for a small fraction of cases with familial inheritance where familial forms of AD are correlated to mutations in three functionally related genes: the amyloid-β protein precursor and presenilins 1 and 2, two key γ-secretase components. The common clinical features of AD are memory impairment that interrupts daily life, difficulty in accomplishing usual tasks, confusion with time or place, trouble understanding visual images and spatial relationships. Age is the most significant risk factor for AD, whereas other risk factors correlated with AD are hypercholesterolemia, hypertension, atherosclerosis, coronary heart disease, smoking, obesity, and diabetes. Despite decades of research, there is no satisfying therapy which will terminate the advancement of AD by acting on the origin of the disease process, whereas currently available therapeutics only provide symptomatic relief but fail to attain a definite cure and prevention. This review also represents the current status of AD in Bangladesh.

Protective Effects of Baicalin on Aβ₁₋₄₂-Induced Learning and Memory Deficit, Oxidative Stress, and Apoptosis in Rat

The accumulation and deposition of β-amyloid peptide (Aβ) in senile plaques and cerebral vasculature is believed to facilitate the progressive neurodegeneration that occurs in the Alzheimer's disease (AD). The present study sought to elucidate possible effects of baicalin, a natural phytochemical, on Aβ toxicity in a rat model of AD. By morris water maze test, Aβ1-42 injection was found to cause learning and memory deficit in rat, which was effectively improved by baicalin treatment. Besides, histological examination showed that baicalin could attenuate the hippocampus injury caused by Aβ. The neurotoxicity mechanism of Aβ is associated with oxidative stress and apoptosis, as revealed by increased malonaldehyde generation and TUNEL-positive cells. Baicalin treatment was able to increase antioxidant capabilities by recovering activities of antioxidant enzymes (superoxide dismutase, catalase, and glutathione peroxidase) and up-regulating their gene expression. Moreover, baicalin effectively prevented Aβ-induced mitochondrial membrane potential decrease, Bax/Bcl-2 ratio increase, cytochrome c release, and caspase-9/-3 activation. In addition, we found that the anti-oxidative effect of baicalin was associated with Nrf2 activation. In conclusion, baicalin effectively improved Aβ-induced learning and memory deficit, hippocampus injury, and neuron apoptosis, making it a promising drug to preventive interventions for AD.

Traditional Korean East Asian medicines and herbal formulations for cognitive impairment

Hanbang, the Traditional Korean Medicine (TKM), is an inseparable component of Korean culture both within the country, and further afield. Korean traditional herbs have been used medicinally to treat sickness and injury for thousands of years. Oriental medicine reflects our ancestor’s wisdom and experience, and as the elderly population in Korea is rapidly increasing, so is the importance of their health problems. The proportion of the population who are over 65 years of age is expected to increase to 24.3% by 2031. Cognitive impairment is common with increasing age, and efforts are made to retain and restore the cognition ability of the elderly. Herbal materials have been considered for this purpose because of their low adverse effects and their cognitive-enhancing or anti-dementia activities. Herbal materials are reported to contain several active compounds that have effects on cognitive function. Here, we enumerate evidence linking TKMs which have shown benefits in memory improvements. Moreover, we have also listed Korean herbal formulations which have been the subject of scientific reports relating to memory improvement.

AAD-2004 Attenuates Progressive Neuronal Loss in the Brain of Tg-betaCTF99/B6 Mouse Model of Alzheimer Disease

Alzheimer's disease (AD) is a neurodegenerative disease that proceeds with the age-dependent neuronal loss, an irreversible event which causes severe cognitive and psychiatric devastations. In the present study, we investigated whether the compound, AAD-2004 [2-hydroxy-5-[2-(4-trifluoromethylphenyl)-ethylaminobenzoic acid] which has anti-oxidant and anti-inflammatory properties, is beneficial for the brain of Tg-betaCTF99/B6 mice, a murine AD model that was recently developed to display age-dependent neuronal loss and neuritic atrophy in the brain. Administration of AAD-2004 in Tg-betaCTF99/B6 mice from 10 months to 18 months of age completely repressed the accumulation of lipid peroxidation in the brain. AAD-2004 markedly suppressed neuronal loss and neuritic atrophy, and partially reversed depleted expression of calbindin in the brain of Tg-beta-CTF99/B6. These results suggest that AAD-2004 affords neurodegeneration in the brain of AD mouse model.

Analysis of differential plaque depositions in the brains of Tg2576 and Tg-APPswe/PS1dE9 transgenic mouse models of Alzheimer disease

Adequate assessment of plaque deposition levels in the brain of mouse models of Alzheimer disease (AD) is required in many core issues of studies on AD, including studies on the mechanisms underlying plaque pathogenesis, identification of cellular factors modifying plaque pathology, and developments of anti-AD drugs. The present study was undertaken to quantitatively evaluate plaque deposition patterns in the brains of the two popular AD models, Tg2576 and Tg-APPswe/PS1dE9 mice. Coronally-cut brain sections of Tg2576 and Tg-APPswe/PS1dE9 mice were prepared and plaque depositions were visualized by staining with anti-amyloid β peptides antibody. Microscopic images of plaque depositions in the prefrontal cortex, parietal cortex, piriform cortex and hippocampus were obtained and the number of plaques in each region was determined by a computer-aided image analysis method. A series of optical images representing a gradual increase of plaque deposition levels were selected in the four different brain regions and were assigned in each with a numerical grade of 1-6, where +1 was lowest and +6, highest, so that plaques per unit in mm² increased "sigmoidally" over the grading scales. Analyzing plaque depositions using the photographic plaque reference panels and a computer-aid image analysis method, it was demonstrated that the brains of Tg2576 mice started to accumulate predominantly small plaques, while the brains of Tg-APPswe/PS1dE9 mice deposited relatively large plaques.

Drug pipeline in neurodegeneration based on transgenic mice models of Alzheimer's disease

Alzheimer's disease (AD) is one of the most important neurodegenerative disorders, bringing about huge medical and social burden in the elderly worldwide. Many aspects of its pathogenesis have remained unclear and no effective treatment exists for it. Within the past 20 years, various mice models harboring AD-related human mutations have been produced. These models imitate diverse AD-related pathologies and have been used for basic and therapeutic investigations in AD. In this regard, there are a wide variety of preclinical trials of potential therapeutic modalities using AD mice models which are of paramount importance for future clinical trials and applications. This review summarizes more than 140 substances and treatment modalities being used in transgenic AD mice models from 2001 to 2011. We also discuss advantages and disadvantages of each model to be used in therapeutic development for AD.

Saponins with neuroprotective effects from the roots of Pulsatilla cernua

Four new oleanene-type triterpenoid saponins together with six known saponins were isolated from the roots of Pulsatilla cernua and their structures were elucidated on the basis of spectroscopic data, including 2D NMR spectra and chemical evidence. Among these one of the aglycones (gypsogenin) is reported for the first time from this genus. Some of these compounds showed significant neuroprotective effects against the cytotoxicity induced by β-amyloid(25-35) (Aβ(25-35)) on human neuroblastoma SH-SY5Y cells.

Behavioral stress causes mitochondrial dysfunction via ABAD up-regulation and aggravates plaque pathology in the brain of a mouse model of Alzheimer disease

Basic and clinical studies have reported that behavioral stress worsens the pathology of Alzheimer disease (AD), but the underlying mechanism has not been clearly understood. In this study, we determined the mechanism by which behavioral stress affects the pathogenesis of AD using Tg-APPswe/PS1dE9 mice, a murine model of AD. Tg-APPswe/PS1dE9 mice that were restrained for 2h daily for 16 consecutive days (2-h/16-day stress) from 6.5months of age had significantly increased Aβ(1-42) levels and plaque deposition in the brain. The 2-h/16-day stress increased oxidative stress and induced mitochondrial dysfunction in the brain. Treatment with glucocorticoid (corticosterone) and Aβ in SH-SY5Y cells increased the expression of 17β-hydroxysteroid dehydrogenase (ABAD), mitochondrial dysfunction, and levels of ROS, whereas blockade of ABAD expression by siRNA-ABAD in SH-SY5Y cells suppressed glucocorticoid-enhanced mitochondrial dysfunction and ROS accumulation. The 2-h/16-day stress up-regulated ABAD expression in mitochondria in the brain of Tg-APPswe/PS1dE9 mice. Moreover, all visible Aβ plaques were costained with anti-ABAD in the brains of Tg-APPswe/PS1dE9 mice. Together, these results suggest that behavioral stress aggravates plaque pathology and mitochondrial dysfunction via up-regulation of ABAD in the brain of a mouse model of AD.

Qualitative and quantitative determination of nine main active constituents in Pulsatilla cernua by high-performance liquid chromatography coupled to electrospray ionization tandem mass spectrometry

A novel qualitative and quantitative method using high-performance liquid chromatography coupled to electrospray ionization tandem mass spectrometry (HPLC-ESI-MS/MS) was developed for simultaneous determination of the nine major active constituents in Pulsatilla cernua (Thunb.) Bercht. et Opiz., namely anemoside A3 (1), anemoside B4 (2), 23-hydroxybetulinic acid (3), cirenshenoside S (4), pulsatilloside B (5), pulsatilloside C (6), oleanolic acid (7), ajugasterone C (8) and β-ecdysterone (9), respectively. A Sapphire C18 column (250 mm × 4.6 mm, 5 μm) and gradient elution were used during the analysis. The identification and quantification of the analytes were achieved on a hybrid quadrupole linear ion trap mass spectrometer. Multiple-reaction monitoring (MRM) scanning was employed for quantification with switching electrospray ion source polarity between positive and negative modes in a single run. All calibration curves showed good linearity (r(2) > 0.9948) within the test ranges. The intra and interday variations for nine analytes were less than 3.95 and 3.78%, respectively. The developed method was successfully applied to determine the investigated compounds in 15 batches of natural and cultured samples of P. cernua. The results indicated that the method was simple, rapid, specific and reliable, which is helpful to comprehensive evaluation of quality of P. cernua.

SK-PC-B70M alleviates neurologic symptoms in G93A-SOD1 amyotrophic lateral sclerosis mice

SK-PC-B70M, an oleanolic-glycoside saponins fraction extracted from the root of Pulsatilla koreana, carries active ingredient(s) that protects the cytotoxicity induced by Aβ(1-42) in SK-N-SH cells. It was recently demonstrated that SK-PC-B70M improved scopolamine-induced deficits of memory consolidation and spatial working memory in rats, and reduced Aβ levels and plaque deposition in the brains of the Tg2576 mouse model of Alzheimer disease. In the present study, we investigated whether SK-PC-B70M produces helpful effects on the pathology of the G93A-SOD1 transgenic mouse model of amyotrophic lateral sclerosis (ALS). Administration of SK-PC-B70M (100 or 400 mg/kg/day) from 8 weeks to 16 weeks of age attenuated neurological deficits of G93A-SOD1 mice in several motor-function-related behavioral tests. SK-PC-B70M treatment significantly suppressed the accumulation of the by-products of lipid peroxidation, malonedialdehyde (MDA) and 4-hydroxy-2-nonenal (HNE), in the spinal cord of G93A-SOD1 mice. Moreover, histologic analysis stained with cresyl violet or anti-choline acetyltransferase (ChAT) revealed that SK-PC-B70M suppressed neuronal loss in the ventral horn of the spinal cords of G93A-SOD1 mice. These results suggest that SK-PC-B70M affords a beneficial effect on neurologic deficits of G93A-SOD1 ALS mice.

A modified preparation (LMK03) of the oriental medicine Jangwonhwan reduces Abeta(1-42) level in the brain of Tg-APPswe/PS1dE9 mouse model of Alzheimer disease

ETHNOPHARMACOLOGICAL RELEVANCE

The oriental medicine Jangwonhwan, which is a boiled extract of 12 medicinal herbs/mushroom, has been prescribed for patients with cognitive dysfunction. Recently, a modified recipe of Jangwonhwan (LMK02-Jangwonhwan) consisting of seven medicinal plants/mushroom, was shown to have a therapeutic potential to ameliorate AD-like pathology.

AIM OF THE STUDY

It was investigated whether a further reduction of Jangwonhwan (LMK03-Jangwonhwan) retains the potency to suppress the AD-like pathology.

MATERIALS AND METHODS

The transgenic mice of Alzheimer disease, Tg-APPswe/PS1dE9, were fed LMK03-Jangwonhwan consisting of two of the herbs, white Poria cocos (Schw.) Wolf and Angelica gigas Nakai, which could protect the AD-like pathology at 300 mg/kg/day of dose for 3 months. In vitro cell biological study, immunohistological and ELISA (enzyme-linked immunosorbent assay) analyses were used to assess its neuroprotective effects against Abeta-induced cell death, and the Abeta accumulation and plaque deposition in the brain.

RESULTS

In vitro study with SH-SY5Y neuroblastoma cells showed that LMK03-Jangwonhwan could protect from cytotoxicity induced by hydrogen peroxide or oligomeric Abeta(1-42). Tg-APPswe/PS1dE9 mice were administered LMK03-Jangwonhwan at 300 mg/kg/day for 3 months from 4.5 months of age. Immunohistological and ELISA analyses showed that LMK03-Jangwonhwan partially reduced Abeta(1-42)and Abeta(1-40) levels and beta-amyloid plaque deposition in the brain of Tg-APPswe/PS1dE9 mice. However, LMK03-Jangwonhwan poorly suppressed accumulation of reactive oxidative stress in the hippocampus of Tg-APPswe/PS1dE9 mice and inefficiently improved the expression of phospho-CREB and calbindin, the cellular factors that were down-regulated in AD-like brains.

CONCLUSIONS

These results suggest that LMK03-Jangwonhwan has a potency to inhibit AD-like pathology at a detectable level, but LMK03 is not likely to retain the major ability of LMK02-Jangwonhwan to modify AD pathology in several AD-related molecular parameters.

Oriental medicine Jangwonhwan reduces Abeta(1-42) level and beta-amyloid deposition in the brain of Tg-APPswe/PS1dE9 mouse model of Alzheimer disease

ETHNOPHARMACOLOGICAL RELEVANCE

Jangwonhwan, a boiled extract of 12 medicinal plants/mushroom including Korean red ginseng (Panax ginseng C.A. Meyer), has been prescribed for patients with cognitive dysfunction and are believed to induce brain activity enhancement, provide light sedation, and facilitate sound sleep.

AIM OF THE STUDY

The present study was carried out to investigate whether Jangwonhwan has a beneficial effect on the brain of Alzheimer disease.

MATERIALS AND METHODS

The transgenic mice of Alzheimer disease, Tg-APPswe/PS1dE9, were fed a modified recipe of Jangwonhwan consisting of a boiled extract of 7 herbs/mushroom (called LMK02-Jangwonhwan) at 400mg/kg/day of dose for 3 months from 4.5 months of age. Immunohistological and ELISA analyses were used to assess the Abeta accumulation and plaque deposition in the brain. Other in vitro and in vivo works were performed to understand the underlying mechanism.

RESULTS

LMK02-Jangwonhwan notably reduced Abeta(1-42) and Abeta(1-40) levels, concomitantly with a reduction of plaque deposition, in the brain of Tg-APPswe/PS1dE9 mice. LMK02-Jangwonhwan partially suppressed oxidative stress accumulation, and prevented the down-regulation of phospho-CREB and calbindin typically seen in the hippocampus of AD-like brains. In vitro study with SH-SY5Y neuroblastoma cells showed that LMK02-Jangwonhwan inhibited oxidative stress and Abeta-induced neurotoxicity.

CONCLUSION

The present study suggests that LMK02-Jangwonhwan confers a therapeutic potential to ameliorate AD-like pathology in the brain of Tg-APPswe/PS1dE9 mice.