Effect of Salvia miltiorrhiza root extract on brain acetylcholinesterase and butyrylcholinesterase activities, their mRNA levels and memory evaluation in rats

Neuroprotective, and memory enhancement effects of Salvia aristata and its phenolic constituents: an in vitro, and in vivo study

BACKGROUND

Alzheimer's disease (AD) is a progressive neurodegenerative disorder characterized by cholinergic dysfunction, neuroinflammation, oxidative stress, and memory impairment. The Salvia genus has been used since ancient times for its anti-inflammatory and neuroprotective properties. In this study, we aimed to investigate the effects of Salvia aristata hydroalcoholic extract (SAHE) and dichloromethane extract (SADE) on various aspects of memory and AD.

METHODS

Column chromatography was utilized in the phytochemical analysis to isolate and purify bioactive compounds. The structures of the isolated compounds were determined through spectroscopic techniques, including 1D and 2D NMR, along with IR, UV, and HRESIMS for the new compound. Cholinesterase inhibitory activity was assessed using a modified Ellman's method. Additionally, the antioxidant activity and metal chelation capacity of SAHE and SADE were evaluated using the DPPH assay and spectroscopic methods, respectively. Moreover, the neuroprotective effects in PC12 cells were investigated using the AlamarBlue assay, and the ability to mitigate scopolamine-induced memory impairment in rats was assessed using the Morris water maze (MWM) test.

RESULTS

In this study, we isolated and structurally elucidated an undescribed compound, namely salvinarin (2), as well as four known compounds including linariin (1), pectolinarin (3), scutellarein 4'-O-methyl-7-O-rutinoside (4), and 5-O-coumaroylquinic acid (5) from SAHE for the first time. In vitro analyses revealed that SAHE, SADE, and linariin exhibited significant neuroprotective effects against H2O2-induced cytotoxicity in PC12 cells. Notably, SAHE demonstrated potent acetylcholinesterase (AChE) inhibition (IC50 = 322.83 ± 1.11 µg/mL), significant antioxidant activity (IC50 = 99.16 ± 1.24 µg/mL), and strong metal chelating capacity toward Cu2+, Zn2+, and Fe2+. Moreover, oral administration of SAHE (400 mg/kg/day) significantly ameliorated memory impairment induced by scopolamine in a rat model. This improvement was evident in parameters such as traveled distance (p < 0.001), escape latency (p < 0.001), and time spent in the target quadrant (p < 0.01) in the Morris water maze test.

CONCLUSIONS

Considering all findings, including significant neuroprotective, antioxidant, and metal-chelating properties, alongside notable efficacy in enhancing memory in rat models, S. aristata could be a potential candidate for memory improvement.

New paradigms in the study of the cholinergic system and metabolic diseases: Acetyl-and-butyrylcholinesterase

Acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) are enzymes that belong to the neuromuscular cholinergic system, their main function is to hydrolyze the neurotransmitter acetylcholine (ACh), through their hydrolysis these enzymes regulate the neuronal and neuromuscular cholinergic system. They have recently attracted considerable attention due to the discovery of new enzymatic and nonenzymatic functions. These discoveries have aroused the interest of numerous scientists, consolidating the relevance of this group of enzymes. Recent investigations have revealed a positive correlation between several risk factors for metabolic syndrome (MetS) and the expression of cholinesterases (ChE's), which underscore the impact of high ChE's activity on the pro-inflammatory state associated with MetS. In addition, the excessive hydrolysis of ACh and other choline esters (succinylcholine, propionylcholine, butyrylcholine, etc.) by both ChE's results in the overproduction of fatty acid precursor metabolites, which facilitate the synthesis of very low-density lipoproteins and triacylglycerols. Participation in these processes may represent the link between ChE's and metabolic disorders. However, further scientific research is required to fully elucidate the involvement of ChE's in metabolic diseases. This review aims to collect recent research studies that contribute to understanding the association between the cholinergic system and metabolic diseases.

Dihydrotanshinone I inhibits ovarian tumor growth by activating oxidative stress through Keap1-mediated Nrf2 ubiquitination degradation

Dihydrotanshinone I (DHT), a bioactive compound in Salvia miltiorrhiza, was reported to exhibit cytotoxicity against various malignancies. However, the underlying mechanism on ovarian cancer remains unclear. Here, DHT inhibited cell viability of ovarian cancer HO8910PM, SKOV3, A2780 and ES2 cells. It showed moderate inhibitory effect on ovarian epithelial IOSE80 cells and lower toxicity than chemotherapy drugs. DHT induced apoptosis and G2 cell cycle arrest accompanied by reduced expression of Bcl-2, Caspase-3, and increased Bax. Meanwhile, DHT increased ROS accumulation, decreased mitochondrial membrane potential and activated oxidative stress in HO8910PM and ES2 cells. Mechanistically, DHT inhibited Nrf2 and p62 expression, Nrf2 target genes and enzymes, and Nrf2 nuclear translocation, while increased the expression of Nrf2 inhibitor Keap1. NAC, a ROS scavenger, rescued DHT-induced proliferation inhibition, ROS generation and Nrf2 inhibition. DHT alleviated tBHQ-induced Nrf2 expression and increased its mRNA level. However, the proteasome inhibitor MG132 blocked DHT-induced Nrf2 inhibition, suggesting a post-translational regulation manner. DHT enhanced Nrf2 binding with Keap1, leading to potentiated Nrf2 ubiquitination degradation. Furthermore, Nrf2 and p62 overexpression blocked DHT-induced Nrf2 and p62 inhibition. Consistent with the in vitro results, DHT significantly delayed tumor growth in HO8910PM and ES2 xenograft nude mice, decreased tumor marker HE4 and CA125 levels, reversed the abnormally expressed proteins including Ki67, Nrf2, p62, Keap1, Bcl-2, CyclinB1, Cdc-2, and antioxidant enzymes SOD, CAT in vivo. Serum from DHT-treated mice also inhibited cell growth in vitro. Taken together, DHT exhibits anti-ovarian tumor effect by activating oxidative stress through ubiquitination-mediated Nrf2 degradation. Our findings implicate a potential application of DHT for ovarian cancer therapy.

Enhanced anti-amnestic effect of donepezil by Ginkgo biloba extract (EGb 761) via further improvement in pro-cholinergic and antioxidative activities

ETHNOPHARMACOLOGICAL RELEVANCE

EGb 761 is a standardized dry extract of Ginkgo biloba L. leaves traditionally used by Eastern Asia and has been associated with beneficial effects on neurodegeneration disorders, including Alzheimer's disease.

AIM OF THE STUDY

Since beneficial interactions between EGb 761 and donepezil have been observed in previous clinical studies, the current study was proposed aiming to further explore related mechanisms from both pharmacokinetics and pharmacodynamics aspects.

MATERIALS AND METHODS

Pharmacodynamic interactions were studied in scopolamine-induced cognitive impairment rats received two-weeks treatment of vehicle, EGb 761 and/or donepezil by the Morris water maze test and ex vivo evaluation of biomarkers of cholinergic transmission and oxidative stress in rat brain. In the meantime, pharmacokinetic profiles of donepezil and bilobalide were obtained and compared among all treatment groups. In addition, impact of the bioavailable EGb 761 components on donepezil brain penetration was evaluated with the hCMEC/D3 cell monolayer model.

RESULTS

Scopolamine-induced rats with co-treatment of EGb 761 and donepezil had significantly improved cognitive function in the Morris water maze test with increased brain levels of superoxide dismutase and decreased brain levels of acetylcholinesterase and malondialdehyde than that with treatment of only EGb 761 or donepezil. Despite such beneficial pharmacodynamics outcomes, the two-week co-treatment of EGb 761 and donepezil did not alter the plasma pharmacokinetics and brain uptake of donepezil or bilobalide, which was further verified in the hCMEC/D3 monolayer model.

CONCLUSION

Co-administration of EGb 761 and donepezil exerted better anti-amnestic effect via further enhanced pro-cholinergic and antioxidative effects of EGb 761 or donepezil in scopolamine-induced cognitive impairment rat without alteration in their systemic/brain exposure.

Laurus nobilis, Salvia sclarea and Salvia officinalis Essential Oils and Hydrolates: Evaluation of Liquid and Vapor Phase Chemical Composition and Biological Activities

Laurus nobilis, Salvia officinalis and Salvia sclarea essential oils (EOs) and hydrolates (HYs) were investigated to define their chemical compositions and biological properties. Gas-chromatography/Mass-spectrometry (GC/MS) and Headspace-GC/MS (HS-GC/MS) techniques were used to characterize the liquid and vapor phase chemical composition of EOs and HYs. 1,8-Cineole (42.2%, 33.5%) and α-pinene (16.7%, 39.0%) were the main compounds of L. nobilis EO; 1,8-cineole (30.3%, 48.4%) and camphor (17.1%, 8.7%) were for S. officinalis EO; linalyl acetate (62.6%, 30.1%) and linalool (11.1%, 28.9%) were for S. sclarea EO for the liquid and vapor phase, respectively. Chemical profile of HYs was characterized by 1,8-cineole (65.1%, 61.4%) as a main constituent of L. nobilis and S. officinalis HYs, while linalool (89.5%) was the main constituent of S. sclarea HY. The antioxidant activity of EOs and HYs was carried out by DPPH and ABTS assays and antimicrobial properties were also investigated by microdilution and the disc diffusion method for liquid and vapor phase against five different bacterial strains such as Escherichia coli ATCC 25922, Pseudomonas fluorescens ATCC 13525 and Acinetobacter bohemicus DSM 102855 among Gram-negative and Bacillus cereus ATCC 10876 and Kocuria marina DSM 16420 among Gram-positive. L. nobilis and S. officinalis EOs demonstrated considerable antibacterial activity, while S. sclarea EO proved to be less effective. Agar diffusion method and vapor phase test showed the EOs activity with the biggest halo inhibition diameters against A. bohemicus and B. cereus. A remarkably high antioxidant activity was determined for L. nobilis showing low EC₅₀ values and also for S. sclarea; good EO results were obtained in both of the used assays. S. officinalis EC₅₀ values were slightly higher to which corresponds to a lower antioxidant activity. Concerning the HYs, the EC₅₀ values for L. nobilis, S. officinalis and S. sclarea were remarkably high corresponding to an extremely low antioxidant activity, as also obtained by expressing the values in Trolox equivalent antioxidant capacity (TEAC).

Overview of Salvia miltiorrhiza as a Potential Therapeutic Agent for Various Diseases: An Update on Efficacy and Mechanisms of Action

Salvia miltiorrhiza Bunge (S. miltiorrhiza) is a medicinal herb that has been used for the treatment for various diseases such as cardiovascular and cerebrovascular diseases in East Asia including Korea. Considering its extensive usage as a therapeutic agent for multiple diseases, there is a need to review previous research regarding its therapeutic benefits and their mechanisms. Therefore, we searched PubMed and PubMed Central for articles reporting its therapeutic effects on certain disease groups including cancers, cardiovascular, liver, and nervous system diseases. This review provides an overview of therapeutic benefits and targets of S. miltiorrhiza, including inflammation, fibrosis, oxidative stress, and apoptosis. The findings on multi-functional properties of S. miltiorrhiza discussed in this article support the efficacy of S. miltiorrhiza extract on various diseases, but also call for further research on the multiple mechanisms that mediate its therapeutic effects.

Therapeutic Potential of Dihydropyridine Calcium Channel Blockers on Oxidative Injury Caused by Organophosphates in Cortex and Cerebellum: An In Vivo Study

This study was designed to investigate the effects of amlodipine (AM), a dihydropyridine calcium channel blocker, on the oxidative damage induced by diazinon (DZN) in the rat cortex and cerebellum. Forty-two rats were randomly divided into six groups. The rats were treated intraperitoneally with normal saline (group 1), AM (9 mg/kg; group 2), DZN (32 mg/kg; group 3) and different doses of AM (3, 6, and 9 mg/kg; groups 4, 5, and 6, respectively) with DZN. After 14 days, the cerebellum and cortex tissues were removed for biochemical and histological experiments. DZN significantly decreased acetylcholinesterase activity (AChE; 57%, p < 0.001 and 39.1%, p < 0.05), depleted total antioxidant capacity (TAC; 46.2%, p < 0.01 and 44.7%, p < 0.05), and increased lactate dehydrogenase activity (LDH; 96%, p < 0.001 and 202%, p < 0.001), nitric oxide (NO; 130%, p < 0.001 and 74.4%, p < 0.001), and lipid peroxidation levels (LPO; 35.6%, p < 0.001 and 128.7%, p < 0.001), in the cerebellum and cortex tissues, respectively. In addition, DZN induced structural alterations in the cerebellum and cortex. Following AM administration, a remarkable improvement was observed in LDH activity and some of the oxidative markers, such as NO and LPO; however, no significant changes were found in AChE activity when the DZN group was compared with the AM-treated groups. This study suggests that AM may prevent DZN-induced neurotoxicity via improvement of the oxidative/antioxidant balance in the cerebellum and cortex tissues.

Chidamide Inhibits Glioma Cells by Increasing Oxidative Stress via the miRNA-338-5p Regulation of Hedgehog Signaling

Objective

Chidamide has a broad spectrum of antitumor activity but its function on glioma remains unknown. The increase of reactive oxygen species (ROS) and reactive nitrogen species (RNS) may control glioma risk by promoting its apoptosis and necrosis. Hedgehog pathway is crucial to glioma cell proliferation and controls ROS production. We aimed to explore the effects of chidamide on the levels of miR-338-5p (glioma cell inhibitor), which may regulate Hedgehog signaling, resulting in the changes of RNS. Materials and Methods. Migration and invasion activities of glioma cells were measured by using the Transwell chamber assay. The expression levels of Sonic Hedgehog (Shh), Indian Hedgehog (Ihh), Desert Hedgehog (Dhh), miR-338-5p, and related molecules were detected by using real-time PCR (RT-PCR) and or Western Blot in U87 and HS683 glioma cells. The effects of chidamide on these molecules were measured by using the miR-338-5p inhibitor or mimics in U87 and HS683 glioma cell lines. ROS and RNS were measured by DCF DA and DAF-FM DA fluorescence. Biomarkers of oxidative stress were measured by using a corresponding kit. Apoptosis and necrosis rates were measured by using flow cytometry.

Results

Chidamide inhibited the growth rate, migration, and invasion of human malignant glioma cells and increased the level of miR-338-5p. miR-338-5p inhibitor or mimics increased or inhibited the growth rate of U87 and HS683 glioma cells. Chidamide inhibited the levels of Shh, Ihh, migration protein E-cadherin, and invading protein MMP-2. The increase in the level of Shh and Ihh led to the reduction in the ROS and RNS levels. miR-338-5p inhibitor or mimics also showed a promoting or inhibitory function for the levels of Shh and Ihh. Furthermore, miR-338-5p mimics and inhibitor inhibited or promoted the migration and invasion of the glioma cells (P < 0.05). Evaluated levels of miR-338-5p increased oxidative stress level and apoptosis and necrosis rate by regulating the levels of biomarkers of oxidative stress (P < 0.05). Evaluated levels of miR-338-5p increased oxidative stress level and apoptosis and necrosis rate by regulating the levels of biomarkers of oxidative stress (

Conclusion

Chidamide inhibits glioma cells by increasing oxidative stress via the miRNA-338-5p regulation of Hedgehog signaling. Chidamide may be a potential drug in the prevention of glioma development.

Multi-Target β-Protease Inhibitors from Andrographis paniculata: In Silico and In Vitro Studies

Natural products derived from plants play a vital role in the discovery of new drug candidates, and these are used for novel therapeutic drug development. Andrographis paniculata and Spilanthes paniculata are used extensively as medicinal herbs for the treatment of various ailments, and are reported to have neuroprotective properties. β-amyloid is a microscopic brain protein whose significant aggregation is detected in mild cognitive impairment and Alzheimer’s disease (AD) brains. The accumulation of β-amyloid disrupts cell communication and triggers inflammation by activating immune cells, leading to neuronal cell death and cognitive disabilities. The proteases acetylcholinesterase (AChE), butyrylcholinesterase (BChE), and beta secretase-1 (BACE-1) have been reported to be correlated with the synthesis and growth of β-amyloid plaques in the brains of AD patients. In the present study, the phenolic compounds from A. paniculata and S. paniculata that have been reported in the literature were selected for the current investigation. Furthermore, we employed molecular docking and molecular dynamics studies of the phenolic compounds with the proteins AChE, BChE, and BACE-1 in order to evaluate the binding characteristics and identify potent anti-amyloid agents against the neurodegenerative diseases such as AD. In this investigation, we predicted three compounds from A. paniculata with maximum binding affinities with cholinesterases and BACE-1. The computational investigations predicted that these compounds follow the rule of five. We further evaluated these molecules for in vitro inhibition activity against all the enzymes. In the in vitro investigations, 3,4-di-o-caffeoylquinic acid (5281780), apigenin (5280443), and 7-o-methylwogonin (188316) were found to be strong inhibitors of AChE, BChE, and BACE-1. These findings suggest that these compounds can be potent multi-target inhibitors of the proteases that might cumulatively work and inhibit the initiation and formation of β-amyloid plaques, which is a prime cause of neurotoxicity and dementia. According to our knowledge, these findings are the first report on natural compounds isolated from A. paniculata as multi-target potent inhibitors and anti-amyloid agents.

Computational insights into β-site amyloid precursor protein enzyme 1 (BACE1) inhibition by tanshinones and salvianolic acids from Salvia miltiorrhiza via molecular docking simulations

The rhizome of Salvia miltiorrhiza has emerged as a rich source of natural therapeutic agents, and its several compounds are supposed to exhibit favorable effects on Alzheimer's disease (AD). The present work investigate the anti-AD potentials of 12 tanshinones, three salvianolic acids and three caffeic acid derivatives from S. miltiorrhiza via the inhibition of β-site amyloid precursor protein cleaving enzyme 1 (BACE1). Among the tested compounds, deoxyneocryptotanshinone (1), salvianolic acid A (13) and salvianolic acid C (15) displayed good inhibitory effect on BACE1 with IC₅₀ values of 11.53 ± 1.13, 13.01 ± 0.32 and 9.18 ± 0.03 μM, respectively. Besides this, enzyme kinetic analysis on BACE1 revealed 13, a competitive type inhibitor while 1 and 15 showed mixed-type inhibition. Furthermore, molecular docking simulation displayed negative binding energies (AutoDock 4.2.6 = -10.0 to -7.1 kcal/mol) of 1, 13, and 15 for BACE1, indicating these compounds bound tightly to the active site of the enzyme with low energy and high affinity. The results of the present study clearly demonstrate that S. miltiorrhiza and its constituents have potential anti-AD activity and can be used as a therapeutic agent for the treatment of AD.

Protective effect of amlodipine on diazinon-induced changes on oxidative/antioxidant balance in rat hippocampus

Oxidative stress (OS) is a main mechanism in organophosphorus poisoning. The effects of calcium channel blockers have been confirmed in decreasing of oxidative stress. In the current study, the effects of amlodipine (AM), as a calcium channel blocker, were evaluated on oxidative damages induced by diazinon (DZN) in hippocampus tissue of Wistar rats. Forty-two rats were divided into six groups and treated intraperitoneally for two weeks. Group 1 served as control received vehicle, group 2 was treated with 9 mg/kg of AM, group 3 (positive control) received DZN (32 mg/kg), Groups 4, 5, and 6 were treated with 3, 6, and 9 mg/kg of AM adjunct with DZN (32 mg/kg), respectively. After 14 days, all the animals were sacrificed under anesthesia and hippocampus tissue and blood samples were collected for biochemical analysis and histopathology experiments. The results showed that DZN caused significant increase in lipid peroxidation (P < 0.001), nitric oxide (P < 0.001) and lactate dehydrogenase (P < 0.001) levels, depletion of total antioxidant capacity (P < 0.01), and structural changes in hippocampus tissues. Following AM administration, a significant improvement was observed in oxidative biomarkers in hippocampus tissues. Additionally, our biochemical findings were related well with histopathological examinations. In conclusion, the data of this study indicated that AM administration may prevent oxidative damages via improving of energy production and preventing of free radical formation in DZN-exposed animals.

Thymoquinone attenuates hepatotoxicity and oxidative damage caused by diazinon: an in vivo study

Thymoquinone (TQ) is the main active constituent of Nigella sativa seeds. The objective of this study was to explore the protective effects of TQ on diazinon (DZN)-induced liver toxicity in the mouse model. The animals were divided into five groups of 6 each and treated intraperitoneally. Group 1 received the vehicle, group 2 was given 16 mg/kg DZN, group 3 received 5 mg/kg TQ, and groups 4 and 5 were treated with 1.25 and 5 mg/kg of TQ as well as 16 mg/kg DZN, respectively. Finally, butyrylcholinesterase (BChE), alanine aminotransferase (ALT), aspartate aminotransferase (AST), and alkaline phosphatase (ALP) serum activity as well as nitric oxide (NO), lipid peroxidation (LPO), total antioxidant capacity (TAC), total thiol molecule (TTM), and histopathological experiments were evaluated in the liver samples. Our findings showed that DZN caused a significant increase in ALT (P < 0.01), AST (P < 0.001), ALP (P < 0.001) serum levels, LPO (P < 0.001) and NO (P < 0.001), the depletion of the TAC (P < 0.05) and TTM (P < 0.001), and structural changes in the liver tissue. Following TQ administration, a significant improvement was observed in the oxidative stress biomarkers in the liver tissue. In addition, our biochemical findings were correlated well to the histopathological examinations. In conclusion, the data from this study indicate that the administration of TQ may prevent liver damage by preventing free radical formation in animals exposed to DZN.

Main Plant Extracts' Active Properties Effective on Scopolamine-Induced Memory Loss

Alzheimer's disease leads to progressive cognitive function loss, which may impair both intellectual capacities and psychosocial aspects. Although the current knowledge points to a multifactorial character of Alzheimer's disease, the most issued pathological hypothesis remains the cholinergic theory. The main animal model used in cholinergic theory research is the scopolamine-induced memory loss model. Although, in some cases, a temporary symptomatic relief can be obtained through targeting the cholinergic or glutamatergic neurotransmitter systems, no current treatment is able to stop or slow cognitive impairment. Many potentially successful therapies are often blocked by the blood-brain barrier since it exhibits permeability only for several classes of active molecules. However, the plant extracts' active molecules are extremely diverse and heterogeneous regarding the biochemical structure. In this way, many active compounds constituting the recently tested plant extracts may exhibit the same general effect on acetylcholine pathway, but on different molecular ground, which can be successfully used in Alzheimer's disease adjuvant therapy.

Cognitive-enhancing and antioxidant activities of the aqueous extract from Markhamia tomentosa (Benth.) K. Schum. stem bark in a rat model of scopolamine

BACKGROUND

Plants of the genus Markhamia have been traditionally used by different tribes in various parts of West African countries, including Cameroun. Markhamia tomentosa (Benth.) K. Schum. (Bignoniaceae) is used as an antimalarial, anti-inflammatory, analgesic, antioxidant and anti-Alzheimer agent. The current study was undertaken in order to investigate its anti-amnesic and antioxidant potential on scopolamine-induced cognitive impairment and to determine its possible mechanism of action.

METHODS

Rats were pretreated with the aqueous extract (50 and 200 mg/kg, p.o.), for 10 days, and received a single injection of scopolamine (0.7 mg/kg, i.p.) before training in Y-maze and radial arm-maze tests. The biochemical parameters in the rat hippocampus were also assessed to explore oxidative status. Statistical analyses were performed using two-way ANOVA followed by Tukey's post hoc test. F values for which p < 0.05 were regarded as statistically significant.

RESULTS

In the scopolamine-treated rats, the aqueous extract improved memory in behavioral tests and decreased the oxidative stress in the rat hippocampus. Also, the aqueous extract exhibited anti-acetylcholinesterase activity.

CONCLUSIONS

These results suggest that the aqueous extract ameliorates scopolamine-induced spatial memory impairment by attenuation of the oxidative stress in the rat hippocampus.