Beneficial effects of an Andrographis paniculata extract and andrographolide on cognitive functions in streptozotocin-induced diabetic rats

The Effects of Andrographis paniculata (Burm.F.) Wall. Ex Nees and Andrographolide on Neuroinflammation in the Treatment of Neurodegenerative Diseases

Neurodegenerative diseases (NDs) affect millions of people worldwide, and to date, Alzheimer's and Parkinson's diseases are the most common NDs. Of the many risk factors for neurodegeneration, the aging process has the most significant impact, to the extent that it is tempting to consider neurodegenerative disease as a manifestation of accelerated aging. However, genetic and environmental factors determine the course of neurodegenerative disease progression. It has been proposed that environmental stimuli influence neuroplasticity. Some clinical studies have shown that healthy lifestyles and the administration of nutraceuticals containing bioactive molecules possessing antioxidant and anti-inflammatory properties have a preventive impact or mitigate symptoms in previously diagnosed patients. Despite ongoing research efforts, the therapies currently used for the treatment of NDs provide only marginal therapeutic benefits; therefore, the focus is now directly on the search for natural products that could be valuable tools in combating these diseases, including the natural compound Andrographis paniculata (Ap) and its main constituent, andrographolide (Andro). Preclinical studies have shown that the aqueous extract of Ap can modulate neuroinflammatory and neurodegenerative responses, reducing inflammatory markers and oxidative stress in various NDs. Therefore, in this review, we will focus on the molecular mechanisms by which Ap and Andro can modulate the processes of neurodegeneration and neuroinflammation, which are significant causes of neuronal death and cognitive decline.

Site-Selective Synthesis of C-17 Ester Derivatives of Natural Andrographolide for Evaluation as a Potential Anticancer Agent

A library of 57 compounds of natural andrographolide was designed, synthesized, and screened for in vitro studies against four human cancer cell lines: A594, PC-3, MCF-7, and HCT-116. Most of the synthesized compounds displayed better cytotoxic profile against all tested cells compared to the parent andrographolide (1). The tested semisynthetic derivatives of andrographolide were found to be more sensitive toward lung carcinoma (A594) and prostate carcinoma (PC-3) cell lines. Among the synthesized compounds, the C-17 p-methoxy phenyl ester analog 8s inhibited cell proliferation effectively in A549 (IC₅₀: 6.6 μM) and PC-3 (IC₅₀: 5.9 μM) cell variants, and compound 9s exhibited the most potent activity against the A594 cell line, with an IC₅₀ value of 3.5 μM. Further anticancer mechanistic investigation demonstrated that compound 9s displayed nuclear morphological changes and increased reactive oxygen species (ROS) with disturbed mitochondrial membrane potential (MMP) that can lead to apoptosis. To know the exact structure confirmation of intermediate compounds 4 and 5, single X-ray crystallography was performed, which supported the complete reaction design of this work.

Andrographis paniculata improves growth and non-specific immunity of shrimp Litopenaeus vannamei, and protects it from Vibrio alginolyticus by reducing oxidative stress and apoptosis

Andrographis paniculata (AP) is a traditional medicinal plant with many pharmacological activities, including anti-inflammatory, antimicrobial, immunity stimulation and so on. Several studies have reported that AP plays a strong role in promoting the immune system of aquatic animals to resist several pathogens. In the present study, we investigate the effects of a diet containing AP on the immune responses, growth, and the resistance to Vibrio alginolyticus (V. alginolyticus) in Litopenaeus vannamei (L. vannamei). Four diets were formulated by adding AP at the dosage of 0% (Control), 0.25%, 0.5%, and 1% in the basal diet, respectively. Each diet was randomly fed to one group with three replicates of shrimps in a 28-day feeding trial. The results showed that dietary AP improved the growth performance and non-specific immune function of shrimps. To investigate the effect of AP on disease resistance of L. vannamei, shrimps fed with diet containing AP were challenged with V. alginolyticus. Compared with the control group, the shrimps fed diet containing AP showed significantly higher survival. Furthermore, the hepatopancreas injury in the shrimp fed with AP was less than control group at 6 h after V. alginolyticus infection. However, no difference was observed in the degree of hepatopancreas injury between AP groups and control group at 12 h and 24 h after V. alginolyticus infection. Based on this result, the samples at 6 h after V. alginolyticus infection was selected for subsequent detection. Reactive oxygen species (ROS) accumulation in hemocytes and O₂^- production in hepatopancreas caused by V. alginolyticus infection was significantly reduced after feeding a diet containing 0.25% and 0.5% AP (p < 0.05). In addition, we found that feeding AP significantly up-regulated the expression of pro-apoptotic genes (Bax, Caspase 3, p53) and down-regulated the expression of anti-apoptotic genes (Bcl-2) in hepatopancreas after V. alginolyticus infection. In conclusion, AP promote the growth and immunity of L. vannamei, and protects shrimps against V. alginolyticus by regulating the oxidative damage and apoptosis. These results provide useful information regarding the effects of AP extracts as a shrimp feed additive for sustainable shrimp culture.

Antioxidant, antidiabetic, and anticholinesterase potential of Chenopodium murale L. extracts using in vitro and in vivo approaches

In this study, Chenopodium murale Linn. extracts have been evaluated for its in vitro antioxidant, enzyme inhibition, and in vivo neuropharmacological properties in streptozotocin (STZ)-induced memory impairment in rat model. First, the plant was subjected to extraction and fractionation, then quantitative phytochemical analysis was performed to estimate the major phytochemical groups in the extract where high amounts of phenolics and saponins were detected in crude and chloroform extract. The highest total phenolic contents, total flavonoid contents, and total tannin content were also recorded in crude extract and chloroform fraction. The in vitro antioxidant potential of chloroform fraction was high with IC50 value of 41.78 and 67.33 μg/mL against DPPH and ABTS radicals, respectively, followed by ethyl acetate fraction. The chloroform fraction (ChMu-Chf) also exhibited potent activity against glucosidase with IC50 of 89.72 ± 0.88 μg/mL followed by ethyl acetate extract (ChMu-Et; IC50 of 140.20 ± 0.98 μg/mL). ChMu-Chf again exhibited potent activity against acetylcholinesterase (AChE) with IC50 of 68.91 ± 0.87 μg/mL followed by ChMu-Et with IC50 of 78.57 ± 0.95 μg/mL. In vivo memory impairment was assessed using the novel object discrimination task, Y-maze, and passive avoidance task. Ex vivo antioxidant enzyme activities and oxidative stress markers like catalase, superoxide dismutase (SOD), malondialdehyde, and glutathione were quantified, and the AChE activity was also determined in the rat brain. No significant differences were observed amongst all the groups treated with crude, chloroform, and ethyl acetate in comparison with positive control donepezil group in connection to initial latency; whereas, the STZ diabetic group displayed a significant fall in recall and retention capability. The blood glucose level was more potently lowered by chloroform extract. The crude extract also increased the SOD level significantly in the brain of the treated rat by 8.01 ± 0.51 and 8.19 ± 0.39 units/mg at 100 and 200 mg/kg body weight (P < 0.01, n = 6), whereas the chloroform extract increased the SOD level to 9.41 ± 0.40 and 9.72 ± 0.51 units/mg, respectively, at 75 and 150 mg/kg body weight as compared to STZ group. The acetylcholine level was also elevated to greater extent by chloroform fraction that might contain a potential inhibitor of acetylcholinesterase. Treatment with C. murale ameliorated cognitive dysfunction in behavioral study, and provided significant defense from neuronal oxidative stress in the brain of the STZ-induced diabetic rats. Thus C. murale Linn. could be an inspiring plant resource that needs to be further investigated for isolation of potential compounds in pure form and their evaluation as a potent neuropharmacological drug.

Polyphenols from Conyza dioscoridis (L.) ameliorate Alzheimer’s disease- like alterations through multi-targeting activities in two animal models

Background

Recent investigations suggested that anticancer agents may inhibit the progression of Alzheimer's disease (AD) pathology. Conyza dioscoridis (L.) was demonstrated to have anticancer, antioxidant, anti-inflammatory and antidiabetic effects. This study was carried out to investigate the efficacy of polyphenols from Conyza dioscoridis (L.) extract (PCDE) on AD.

Methods

Impacts of 3 doses of PCDE and donepezil, a reference drug, on the features of Alzheimer's disease in two animal models were investigated.

Results

PCDE ameliorated the memory and learning impairment shown in rats following a single dose of scopolamine (scopolamine model) or 17 weeks of high-fat/high-fructose(HF/Hfr) diet coupled with a single dose of streptozotocin, (25 mg/kg) (T2D model). They reduced significantly the high hippocampal cholinesterase activity in the two models of rats. Administration of PCDE for 8 weeks in the T2D model showed a significant reduction in hippocampal GSK-3β, caspase-3 activity and increase in the inhibited glutamate receptor expression (AMPA GluR1 subunit and NMDA receptor subunits NR1, NR2A, NR2B). A significant reduction of HOMA-insulin resistance and serum hypercholesterolemia was observed. The Tau hyperphosphorylation and Aβ 1–42 generation in the hippocampal of T2D rats were significantly decreased by PCDE. Modulation of the oxidative stress markers, (rise in GH and SOD; decrease in MDA levels) and a significant reduction of TNF-α and IL-1β in the hippocampus of T2D rats treated by PCDE extract were important findings in this study. The highest dose tested was 4% of the highest safe dose.

Conclusion

Our study suggests that PCDE is multi-targeting agent with multiple beneficial activities in combating features of AD. This study may provide a novel therapeutic strategy for AD treatment that warrants clinical studies.

Study on the mechanism of andrographolide activation

Andrographolide is a natural antibiotic that has the ability to dispel heat, detoxify, reduce inflammation, and relieve pain. Recent research has shown that it can exert anti-inflammatory effects via multiple pathways and multiple targets (mediated by NF-κB, JAK/STAT, T cell receptor, and other signaling pathways). It can inhibit human lung cancer cells, colon cancer cells, osteosarcoma cells, and other tumor cells, as well as reduce bacterial virulence and inhibit virus-induced cell apoptosis. It can also regulate inflammatory mediator expression to protect the nervous system and effectively prevent mental illness. Additionally, andrographolide regulates the immune system, treats cardiovascular and cerebral vascular diseases, protects the liver, and the gallbladder. It is clear that andrographolide has a huge range of potential applications. The mechanism of andrographolide’s anti-inflammatory, antibacterial, antiviral, and nervous system defense in recent years have been reviewed in this article.

Potential pharmacokinetic and pharmacodynamic herb-drug interactions of Andrographis paniculata (Burm. f.) and andrographolide: A systematic review

Introduction: Herb–drug interactions (HDIs) in pharmacokinetics and pharmacodynamics can occur when natural compounds are used in combination with drugs. This study aimed to review the potential interaction of Andrographis paniculata (Burm. f.) extract (APE) and its primary compound andrographolide (AND) with several drugs exhibiting various pharmacological activities.Methods: In this systematic review, articles were collected from international databases such as PubMed, Science Direct, Springer Link, and Scopus until August 2021. The following keywords were used: Andrographis paniculata, andrographolide, HDI, drug interaction, pharmacokinetics, and pharmacology. This review was written in accordance with the guidelines of the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA), SYRCLE’s risk of bias (RoB) tool for animal intervention studies, and Cochrane RoB 2 tool to analyze the RoB for qualitative assessment.Results: Twelve articles were included in accordance with the inclusion and exclusion criteria of this study. Five studies explored the potential of HDIs for combining APE with drugs and AND with theophylline, etoricoxib, nabumetone, naproxen, and tolbutamide. Five studies focused on AND in combination with aminophylline and doxofylline, meloxicam, glyburide, glimepiride, metformin, and warfarin. Two studies tested the combination of APE with gliclazide and midazolam. The HDI mechanism involving the inhibition or induction of cytochrome P450 enzyme expression was dominant in influencing the drug’s pharmacokinetic profile. Pharmacological studies on the combination of several drugs, particularly anti-inflammatory and antidiabetic drugs, showed a synergistic activity.Conclusion: APE and AND have potential pharmacokinetic and pharmacodynamic HDIs with various drugs. This study can be used as a therapeutic consideration in clinical aspects related to the possibility of HDIs of A. paniculata (Burm. f.).

The role of traditional Chinese medicine in the treatment of cognitive dysfunction in type 2 diabetes

ETHNOPHARMACOLOGICAL RELEVANCE

Diabetic cognitive dysfunction (DCD) is mainly one of the complications of type 2 diabetes mellitus (T2DM) with complex and obscure pathogenesis. Extensive evidence has demonstrated the effectiveness and safety of traditional Chinese medicine (TCM) for DCD management.

AIM OF THE STUDY

This review attempted to systematically summarize the possible pathogenesis of DCD and the current Chinese medicine on the treatment of DCD.

MATERIALS AND METHODS

We acquired information of TCM on DCD treatment from PubMed, Web of Science, Science Direct and CNKI databases. We then dissected the potential mechanisms of currently reported TCMs and their active ingredients for the treatment of DCD by discussing the deficiencies and giving further recommendations.

RESULTS

Most TCMs and their active ingredients could improve DCD through alleviating insulin resistance, microvascular dysfunction, abnormal gut microbiota composition, inflammation, and the damages of the blood-brain barrier, cerebrovascular and neurons under hyperglycemia conditions.

CONCLUSIONS

TCM is effective in the treatment of DCD with few adverse reactions. A large number of in vivo and in vitro, and clinical trials are still needed to further reveal the potential quality markers of TCM on DCD treatment.

Diosgenin Attenuates Cognitive Impairment in Streptozotocin-Induced Diabetic Rats: Underlying Mechanisms

OBJECTIVE

Prolonged diabetes mellitus causes impairments of cognition and attentional dysfunctions. Diosgenin belongs to a group of steroidal saponins with reported anti-diabetic and numerous protective properties. This research aimed to assess the effect of diosgenin on beneficially ameliorating learning and memory decline in a rat model of type 1 diabetes caused by streptozotocin (STZ) and to explore its modes of action including involvement in oxidative stress and inflammation.

METHODS

Rats were assigned to one of four experimental groups, comprising control, control under treatment with diosgenin, diabetic, and diabetic under treatment with diosgenin. Diosgenin was given daily p.o. (40 mg/kg) for 5 weeks.

RESULTS

The administration of diosgenin to the diabetic group reduced the deficits of functional performance in behavioral tests, consisting of Y-maze, passive avoidance, radial arm maze, and novel object discrimination tasks (recognitive). Furthermore, diosgenin treatment attenuated hippocampal acetylcholinesterase activity and malon-dialdehyde, along with improvement of antioxidants such as superoxide dismutase and glutathione. Meanwhile, the hippocampal levels of inflammatory indicators, namely interleukin 6, nuclear factor-κB, toll-like receptor 4, tumor necrosis factor α, and astrocyte-specific biomarker glial fibrillary acidic protein, were lower and, on the other hand, tissue levels of nuclear factor (erythroid-derived 2)-related factor 2 were elevated upon diosgenin administration. Besides, the mushroom-like spines of the pyramidal neurons of the hippocampal CA1 area decreased in the diabetic group, and this was alleviated following diosgenin medication.

CONCLUSIONS

Taken together, diosgenin is capable of ameliorating cognitive deficits in STZ-diabetic animals, partly due to its amelioration of oxidative stress, inflammation, astrogliosis, and possibly improvement of cholinergic function in addition to its neuroprotective potential.

Securidaca inappendiculata Polyphenol Rich Extract Counteracts Cognitive Deficits, Neuropathy, Neuroinflammation and Oxidative Stress in Diabetic Encephalopathic Rats via p38 MAPK/Nrf2/HO-1 Pathways

Diabetic encephalopathy is one of the serious emerging complication of diabetes. Securidaca inappendiculata is an important medicinal plant with excellent antioxidant and anti-inflammatory properties. This study investigated the neuroprotective effects of S. inappendiculata polyphenol rich extract (SiPE) against diabetic encephalopathy in rats and elucidated the potential mechanisms of action. Type 2 diabetes mellitus (T2DM) was induced using high fructose solution/intraperitoneal injection of streptozotocin and the diabetic rats were treated with SiPE (50, 100 and 200 mg/kg) for 8 weeks. Learning and memory functions were assessed using the Morris water and Y maze tests, depressive behaviour was evaluated using forced swimming and open field tests, while neuropathic pain assessment was assessed using hot plate, tail immersion and formalin tests. After the experiments, acetylcholinesterase (AChE), oxidative stress biomarkers and proinflammatory cytokines, caspase-3 and nuclear factor kappa-light-chain-enhancer of activated B (NF-κB) were determined by ELISA kits. In addition, the expression levels of p38, phospho-p38 (p-p38), nuclear factor erythroid 2-related factor 2 (Nrf2) and heme oxygenase-1 (HO-1) were determined by western blot analyses. The results indicated that SiPE administration significantly lowered blood glucose level, attenuated body weight loss, thermal/chemical hyperalgesia, improved behavioural deficit in the Morris water maze, Y maze test and reduced depressive-like behaviours. Furthermore, SiPE reduced AChE, caspase-3, NF-κB, malonaldehyde malondialdehyde levels and simultaneously increased antioxidant enzymes activity in the brain tissues of diabetic rats. SiPE administration also significantly suppressed p38 MAPK pathway and upregulated the Nrf2 pathway. The findings suggested that SiPE exerted antidiabetic encephalopathy effects via modulation of oxidative stress and inflammation.

Biotechnological production of diterpenoid lactones from cell and organ cultures of Andrographis paniculata

Andrographis paniculata (AP) is a medicinal plant that is traditionally used in Indian, Chinese, Malay, Thai, and Oriental system of medicines to treat various disorders. AP consists of andrographolide (AD), 14-deoxy-11,12-didehydroandrographolide (DDAD), and neoandrographolide (NAD) as major diterpene lactones which has extremely bitter properties; therefore, AP is commonly called "King of bitters." AD, DDAD, and NAD are reported to possess therapeutic values such as antioxidant, immunostimulatory, hepatoprotective, anti-cancer, anti-inflammatory, anti-rheumatoidal, anti-malarial, anti-leishmanial, anti-fertility, anti-obesity, antipyretic, and antimicrobial attributes. According to the Indian Pharmacopoeia, the leaves and tender shoots of AP yield up to 1%, 0.16%, and 0.11% of AD, DDAD, and NAD, respectively, on a dry-weight basis. However, variability in the accumulation of AD, DDAD, and NAD in plants has been reported with respect to species, genotype, season, phenological stage, plant part used, and geography of a region of cultivation. Therefore, cell and tissue culture systems especially cell, shoot, and adventitious root cultures are explored as alternatives for constant and higher production of AD, DDAD, and NAD. This review explores the prospects of exploiting the plant cell and tissue culture systems for the controlled production of AD, DDAD, and NAD. Various strategies such as elicitation by using biological and chemical elicitors are explored for the enhancement of accumulation of AD, DDAD, and NAD in cell and organ cultures. KEY POINTS: • This review explores the possibilities of diterpene lactone production from cell and organ cultures. • Various strategies are explored for the enhanced accumulation of AD, DDAD, and NAD in cell and organ cultures. • Prospects of diterpene lactone production are highlighted.

Investigating pharmacological mechanisms of andrographolide on non-alcoholic steatohepatitis (NASH): A bioinformatics approach of network pharmacology

Objective

To investigate the mechanisms of andrographolide against non-alcoholic steatohepatitis (NASH) based on network pharmacology, so as to provide a reference for further study of andrographolide in the treatment of NASH and other metabolic diseases.

Methods

The methionine- and choline-deficient (MCD) diet-induced NASH mice were treated by administration of andrographolide, and serum transaminase and pathological changes were analyzed. The network pharmacology-based bioinformatic strategy was then used to search the potential targets, construct protein–protein interaction (PPI) network, analyze gene ontology (GO) and Kyoto encyclopedia of genes and genomes (KEGG) pathway enrichment, and conduct molecular docking to explore the molecular mechanisms.

Results

The predicted core targets TNF, MAPK8, IL6, IL1B and AKT1 were enriched in non-alcoholic fatty liver disease (NAFLD) signaling pathway and against NASH by regulation of de novo fatty acids synthesis, anti-inflammation and anti-oxidation.

Conclusion

This work provides a scientific basis for further demonstration of the anti-NASH mechanisms of andrographolide.

Andrographis paniculata and Its Main Bioactive Ingredient Andrographolide Decrease Alcohol Drinking and Seeking in Rats Through Activation of Nuclear PPARγ Pathway

BACKGROUND AND AIMS

Andrographis paniculata is an annual herbaceous plant which belongs to the Acanthaceae family. Extracts from this plant have shown hepatoprotective, anti-inflammatory and antidiabetic properties, at least in part, through activation of the nuclear receptor Peroxisome Proliferator-Activated Receptor-gamma (PPAR γ). Recent evidence has demonstrated that activation of PPARγ reduces alcohol drinking and seeking in Marchigian Sardinian (msP) alcohol-preferring rats.

METHODS

The present study evaluated whether A. paniculata reduces alcohol drinking and relapse in msP rats by activating PPARγ.

RESULTS

Oral administration of an A. paniculata dried extract (0, 15, 150 mg/kg) lowered voluntary alcohol consumption in a dose-dependent manner and achieved ~65% reduction at the dose of 450 mg/kg. Water and food consumption were not affected by the treatment. Administration of Andrographolide (5 and 10 mg/kg), the main active component of A. paniculata, also reduced alcohol drinking. This effect was suppressed by the selective PPARγ antagonist GW9662. Subsequently, we showed that oral administration of A. paniculata (0, 150, 450 mg/kg) prevented yohimbine- but not cues-induced reinstatement of alcohol seeking.

CONCLUSIONS

Results point to A. paniculata-mediated PPARγactivation as a possible therapeutic strategy to treat alcohol use disorder.

Traditional Herbal Medicines Against CNS Disorders from Bangladesh

The majority of the population in Bangladesh uses traditional plant-based medicines to manage various ailments, including central nervous system (CNS) disorders. This review presents ethnobotanical information and relevant scientific studies on plants used in traditional healthcare for the management of various CNS disorders in Bangladesh. The information on the medicinal plants of Bangladesh effective against CNS disorders published in scientific journals, books, and reports was compiled from different electronic databases using specific key words. The present article provides comprehensive information on a total of 224 medicinal plant species belonging to 81 families used for the treatment of CNS disorders by the various peoples of Bangladesh. In total, we reviewed more than 290 relevant papers. In this study, leaves were found as the most often used plant organ, followed by roots, fruits, whole plants, barks, seeds, stems, rhizomes, and flowers. The Fabaceae family contributes the highest number of used species, followed by Rubiaceae, Lamiaceae, Cucurbitaceae, Vitaceae, Euphorbiaceae, Malvaceae, and Zingiberaceae. The most frequently used species (in decreasing order) are Asparagus racemosus, Centella asiatica, Stephania japonica, Aegle marmelos, Coccinia grandis, Tabernaemontana divaricata, Bacopa monnieri, Abroma augusta, and Scoparia dulcis. This review may serve as a starting point for a rational search for neuroactive natural products against CNS disorders within the Flora of Bangladesh.

Evaluation of the neuroprotective effect of donepezil in type 2 diabetic rats

Recent studies raise the possibility that donepezil can delay the progression of Alzheimer's disease (AD). This research evaluated the efficacy of donepezil in an animal model with brain insulin resistance and AD-like alterations. Rats were fed with high-fat/high-fructose (HF/Hfr) diet during the study period (17 weeks) and received one injection of streptozotocin (STZ) (25 mg/kg) after 8 weeks of starting the study. Diabetic (T2D) rats were treated with donepezil (4 mg/kg; p.o.) or vehicle for 8 weeks after STZ injection. The influence of donepezil on AD-related behavioral, biochemical, and neuropathological changes was investigated in T2D rats. Treatment of diabetic rats with donepezil led to a significant decrease in both amyloid-β deposition and the raised hippocampal activity of cholinesterase (ChE). It significantly increased the suppressed glutamate receptor expression (AMPA GluR1 subunit and NMDA receptor subunits NR1, NR2A, NR2B). It also improved cognitive dysfunction in the passive avoidance and the Morris water maze tests. However, donepezil treatment did not significantly decrease the elevated levels of P-tau, caspase-3, GSK-3β, MDA, TNF-α, and IL-1β in the hippocampus of diabetic rats. Also, it did not restore the suppressed levels of glutathione and superoxide dismutase in the brain of these rats. Moreover, donepezil did not alter the elevated serum level of glucose, insulin, and total cholesterol. These findings suggest that donepezil treatment could ameliorate learning and memory impairment in T2D rats through reversal of some of the AD-related alterations, including reduction of amyloid-β burden and ChE activity as well as restoration of glutamate receptor expression. However, lack of any significant effect on P-tau load, oxidative stress, neuroinflammation, and insulin resistance raises the question about the ability of donepezil to delay the development or arrest the progression of T2D-induced AD and it is still a matter of debate that requires further studies.

Andrographolide modulates HNF4α activity imparting on hepatic metabolism

Hepatic nuclear factor 4 alpha (HNF4α) drives the expression of apolipoprotein B (ApoB), microsomal triglyceride transfer protein (MTP) and phospholipase A2 G12B (PLA2G12B), governing hepatic very-low-density lipoprotein (VLDL) production and secretion. Andrographolide (AP) is a major constituent isolated from Andrographis paniculata. We found that AP can disrupt the interaction between HNF4α and its coactivator peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC1α). Virtual docking and mutational analysis indicated that arginine 235 of HNF4α is essential for binding to AP. As a consequence of antagonizing the activity of HNF4α, AP suppresses the expression of ApoB, MTP and PLA2G12B and reduces the rate of hepatic VLDL secretion in vivo. AP additionally reduced gluconeogenesis via down-regulating the expression of HNF4α target genes phosphoenolpyruvate carboxykinase (Pepck) and glucose-6-phosphatase (G6pc). Collectively, our results suggest that AP affects liver function via modulating the transcriptional activity of HNF4α.

Andrographolide Exerts Antihyperglycemic Effect through Strengthening Intestinal Barrier Function and Increasing Microbial Composition of Akkermansia muciniphila

Accumulating evidence indicates that type 2 diabetes (T2D) is associated with intestinal barrier dysfunction and dysbiosis, implying the potential targets for T2D therapeutics. Andrographolide was reported to have several beneficial effects on diabetes and its associated complications. However, the protective role of andrographolide, as well as its underlying mechanism against T2D, remains elusive. Herein, we reported that andrographolide enhanced intestinal barrier integrity in LPS-induced Caco-2 cells as indicated by the improvement of cell monolayer barrier permeability and upregulation of tight junction protein expression. In addition, andrographolide alleviated LPS-induced oxidative stress by preventing ROS and superoxide anion radical overproduction and reversing glutathione depletion. In line with the in vitro results, andrographolide reduced metabolic endotoxemia and strengthened gut barrier integrity in db/db diabetic mice. We also found that andrographolide appeared to ameliorate glucose intolerance and insulin resistance and attenuated diabetes-associated redox disturbance and inflammation. Furthermore, our results indicated that andrographolide modified gut microbiota composition as indicated by elevated Bacteroidetes/Firmicutes ratio, enriched microbial species of Akkermansia muciniphila, and increased SCFAs level. Taken together, this study demonstrated that andrographolide exerted a glucose-lowering effect through strengthening intestinal barrier function and increasing the microbial species of A. muciniphila, which illuminates a plausible approach to prevent T2D by regulating gut barrier integrity and shaping intestinal microbiota composition.

Traditional Chinese Medicine: Role in Reducing β-Amyloid, Apoptosis, Autophagy, Neuroinflammation, Oxidative Stress, and Mitochondrial Dysfunction of Alzheimer's Disease

Alzheimer's disease (AD) is a progressive age-related neurodegenerative disease characterized by memory loss and cognitive impairment. The major characteristics of AD are amyloid β plaques, apoptosis, autophagy dysfunction, neuroinflammation, oxidative stress, and mitochondrial dysfunction. These are mostly used as the significant indicators for selecting the effects of potential drugs. It is imperative to explain AD pathogenesis and realize productive treatments. Although the currently used chemical drugs for clinical applications of AD are effective in managing the symptoms, they are inadequate to achieve anticipated preventive or therapeutic outcomes. There are new strategies for treating AD. Traditional Chinese Medicine (TCM) has accumulated thousands of years of experience in treating dementia. Nowadays, numerous modern pharmacological studies have verified the efficacy of many bioactive ingredients isolated from TCM for AD treatment. In this review, representative TCM for the treatment of AD are discussed, and among these herbal medicines, the Lamiaceae family accounts for the highest proportion. It is concluded that monomers and extracts from TCM have potential therapeutic effect for AD treatment.

A network-based analysis of key pharmacological pathways of Andrographis paniculata acting on Alzheimer's disease and experimental validation

ETHNOPHARMACOLOGICAL RELEVANCE

Andrographis paniculata (AP) is a native plant with anti-inflammatory and antioxidant properties and used as an official herbal medicine. Recently more and more researches have indicated that AP shows pharmacological effects on Alzheimer's disease (AD) but its mechanism is unclear.

AIMS OF THE STUDY

Network pharmacology approach combined with experimental validation was developed to reveal the underlying molecular mechanisms of AP in treating AD.

MATERIALS AND METHODS

The compounds of AP from TCM database, the AD-related targets from disease database and the targets corresponding to compounds from swissTargetPrediction were collected. Then DAVID database was used for annotation and enrichment pathways, meanwhile the compound-target, protein-protein interaction from String database and compound-target-pathway network was constructed, molecular modeling was performed using Sybyl-x. Okadaic acid (OKA)-induced cytotoxicity model in PC12 cells was established to verify the mechanism of AP and the key proteins were detected by western blotting.

RESULTS

28 AP components were identified after ADME filter analysis and 52 targets were gained via mapping predicted targets into AD-related proteins. In addition, after multiple network analysis, the 22 hub target genes were enriched onto pathways involved in AD, such as neuroactive ligand-receptor interaction, serotonergic synapse, Alzheimer's disease, PI3K-Akt and NF-kB signaling pathway. Interestingly, molecular docking simulation revealed that the targets including PTGS2, BACE1, GSK3B and IKBKB had good ability to combine with AP components. Experimental validation in an in vitro system proved that AP treatment obviously increased in levels inactive of p-GSK3β (P < 0.05) and decreased in levels of BACE (P < 0.05), PTGS2 (namely COX2, P < 0.05) and NF-kB protein (P < 0.05) compare with OKA treated group.

CONCLUSION

Our data provided convincing evidence that the neuroprotective effects of AP might be partially related to their regulation of the APP-BACE1-GSK3B signal axis and inflammation, which should be the focus of study in this field in the future.

Andrographolide, a Natural Antioxidant: An Update

Traditionally, Andrographis paniculata has been used as an herbal remedy for lung infection treatments. Its leaves contain a diterpenoid labdane called andrographolide responsible for a wide range of biological activities such as antioxidant, anti-inflammatory, and anti-cancer properties. This manuscript is a brief review of the antioxidant mechanisms and the regulation of the Nrf2 (nuclear factor (erythroid-derived 2)-like 2) signaling pathway by andrographolide.

Review of the Effect of Natural Compounds and Extracts on Neurodegeneration in Animal Models of Diabetes Mellitus

Diabetes mellitus is a chronic metabolic disease with a high prevalence in the Western population. It is characterized by pancreas failure to produce insulin, which involves high blood glucose levels. The two main forms of diabetes are type 1 and type 2 diabetes, which correspond with >85% of the cases. Diabetes shows several associated alterations including vascular dysfunction, neuropathies as well as central complications. Brain alterations in diabetes are widely studied; however, the mechanisms implicated have not been completely elucidated. Diabetic brain shows a wide profile of micro and macrostructural changes, such as neurovascular deterioration or neuroinflammation leading to neurodegeneration and progressive cognition dysfunction. Natural compounds (single isolated compounds and/or natural extracts) have been widely assessed in metabolic disorders and many of them have also shown antioxidant, antiinflamatory and neuroprotective properties at central level. This work reviews natural compounds with brain neuroprotective activities, taking into account several therapeutic targets: Inflammation and oxidative stress, vascular damage, neuronal loss or cognitive impairment. Altogether, a wide range of natural extracts and compounds contribute to limit neurodegeneration and cognitive dysfunction under diabetic state. Therefore, they could broaden therapeutic alternatives to reduce or slow down complications associated with diabetes at central level.

Medicinal plants with acetylcholinesterase inhibitory activity

Alzheimer's disease, a progressive neurodegenerative disease, is characterised by hypofunction of acetylcholine (ACh) neurotransmitter in the distinct region of brain. Acetylcholinesterase (AChE) is an enzyme that metabolises the ACh at synaptic cleft resulting in Alzheimer's disease. Medicinal plants have been used to treat numerous ailments and improve human health from ancient time. A traditional system of medicine is long recognised for its effective management of neurological disorders. The present review confers the scope of some common medicinal plants with a special focus on AChE-mediated central nervous system complications especially Alzheimer's disease. Literature suggests that medicinal plants reduce neuronal dysfunctions by reducing AChE activity in different brain regions. In some instances, activation of AChE activity by medicinal plants also showed therapeutic potential. In conclusion, medicinal plants have a wide scope and possess therapeutic potential to efficiently manage neurological disorders associated with AChE dysregulation.

Overview of pharmacological activities of Andrographis paniculata and its major compound andrographolide

Andrographis paniculata (A. paniculata) is a medicinal plant traditionally used as anti-inflammation and anti-bacteria herb. Andrographolide, the major active component of A. paniculata, exhibits diverse pharmacological activities, including anti-inflammation, anti-cancer, anti-obesity, anti-diabetes, and other activities. In this article, we comprehensively review the therapeutic potential of A. paniculata and andrographolide focusing on the mechanisms of action and clinical application. We systemically discuss the structure-activity relationship of andrographolide and derivatives. Despite the various pharmacological activities and formula of A. paniculata and andrographolide, we propose further development of more structural derivatives of andrographolide with reduced toxicity and increased therapeutic efficacy is still needed for the clinical application of this ancient mighty herb and its major component.

Natural products as reservoirs of novel therapeutic agents

Since ancient times, natural products from plants, animals, microbial and marine sources have been exploited for treatment of several diseases. The knowledge of our ancestors is the base of modern drug discovery process. However, due to the presence of extensive biodiversity in natural sources, the percentage of secondary metabolites screened for bioactivity is low. This review aims to provide a brief overview of historically significant natural therapeutic agents along with some current potential drug candidates. It will also provide an insight into pros and cons of natural product discovery and how development of recent approaches has answered the challenges associated with it.

The toxic influence of dibromoacetic acid on the hippocampus and pre-frontal cortex of rat: involvement of neuroinflammation response and oxidative stress

Dibromoacetic acid (DBA) exsits in drinking water as a by-product of disinfection as a result of chlorination or ozonation processes. Hippocampus and pre-frontal cortex are the key structures in memory formation and weanling babies are more sensitive to environmental toxicant than adults, so this study was conducted to evaluate the potential neurotoxicity effects of DBA exposure when administered intragastrically for 4 weeks to weanling Sprague-Dawley rats, at concentration of 0, 20, 50, 125 mg/kg via the neurobehavioral and neurochemical effects. Results indicated that animals weight gain and food consumption were not significantly affected by DBA. However, morris water maze test showed varying degrees of changes between control and high-dose group. Additionally, the level of malondialdehyde (MDA) and generation of reactive oxygen species (ROS) in the hippocampus and pre-frontal cortex of rats increased significantly. The activities of total superoxide dismutase (SOD) and the glutathione (GSH) content in the hippocampus and pre-frontal cortex of rats decreased significantly after treatment with DBA. Treatment with DBA increased the protein and mRNA expression of Iba-1, NF-κB, TNF-α, IL-6, IL-1β and HO-1 in the hippocampus and pre-frontal cortex of rats. These data suggested that DBA had a toxic influence on the hippocampus and pre-frontal cortex of rats, and that the mechanism of toxicity might be associated with the neuroinflammation response and oxidative stress.

Andrographolide, a New Hope in the Prevention and Treatment of Metabolic Syndrome

Recently, the use of plant-derived medicines is increasing interest in the prevention and treatment of a variety of disorders including metabolic syndromes. Metabolic syndrome is one of the major risk factors for cardiovascular diseases (CVDs) and incidence of mortality worldwide. Scientific evidence suggests that Andrographis paniculata and its derived components, especially andrographolide (AGL) and its analogs/derivatives have a broad spectrum of biological activities. This review aims to sketch the activity of AGL and its analogs/derivatives against the components of metabolic syndromes such as diabetes, hyperlipidemia, hypertension, and obesity. Additionally, AGL activity against CVDs is also summarized. The finding suggests that AGL and its analogs/derivatives have a potential role in the management of metabolic syndrome; however, more studies should be conducted to evaluate their effectiveness.

Andrographolide Activates Keap1/Nrf2/ARE/HO-1 Pathway in HT22 Cells and Suppresses Microglial Activation by Aβ42 through Nrf2-Related Inflammatory Response

Therapeutic approach of Alzheimer's disease (AD) has been gradually diversified. We examined the therapeutic and preventive potential of andrographolide, which is a lactone diterpenoid from Andrographis paniculata, and focused on the Kelch-like ECH-associated protein 1 (Keap1)/nuclear factor (erythroid-derived 2)-like 2 (Nrf2)-mediated heme oxygenase (HO)-1-inducing effects and the inhibitory activity of amyloid beta (Aβ)₄₂-induced microglial activation related to Nrf2 and nuclear factor κB (NF-κB)-mediated inflammatory responses. Andrographolide induced the expression and translocation of Nrf2 from the cytoplasm to the nucleus, thereby activating antioxidant response element (ARE) gene transcription and HO-1 expression in murine hippocampal HT22 cells. Andrographolide eliminated intracellular Aβ₄₂ in BV-2 cells and decreased the production of interleukin (IL)-6, IL-1β, prostaglandin (PG)E₂, and nitric oxide (NO) because of artificial phagocytic Aβ₄₂. It decreased pNF-κB accumulation in the nucleus and the expression of inducible nitric oxide synthase (i-NOS) and cyclooxygenase II (COX-II) in the microglial BV-2 cell line. In summary, andrographolide activates Nrf2-mediated HO-1 expression and inhibits Aβ₄₂-overexpressed microglial BV-2 cell activation. These results suggested that andrographolide might have the potential for further examination of the therapeutics of AD.

S-allyl cysteine ameliorates cognitive deficits in streptozotocin-diabetic rats via suppression of oxidative stress, inflammation, and acetylcholinesterase

Diabetes mellitus (DM) is associated with learning, memory, and cognitive deficits. S-allyl cysteine (SAC) is the main organosulfur bioactive molecule in aged garlic extract with anti-diabetic, antioxidant, anti-inflammatory and nootropic property. This research was conducted to evaluate the efficacy of SAC on alleviation of learning and memory deficits in streptozotocin (STZ)-diabetic rats and to explore involvement of toll-like receptor 4 (TLR4), nuclear factor (erythroid-derived 2)-like 2 (Nrf2), nuclear factor-kappa B (NF-κB), and heme oxygenase 1 (HO-1) signaling cascade. Male Wistar rats were divided into control, diabetic, SAC-treated diabetic, and glibenclamide-treated diabetic (positive control) groups. SAC was administered at a dose of 150mg/kg for seven weeks. Treatment of diabetic rats with SAC lowered serum glucose, improved spatial recognition memory in Y maze, discrimination ratio in novel object recognition task, and restored step-through latency (STL) in passive avoidance paradigm. In addition, SAC reduced acetylcholinesterase activity, lipid peroxidation marker malondialdehyde (MDA) and augmented antioxidant defensive system including superoxide dismutase (SOD), catalase and reduced glutathione (GSH) in hippocampal lysate. Meanwhile, SAC lowered hippocampal NF-kB, TLR4, and TNFα and prevented reduction of Nrf2 and heme oxygenase-1 (HO-1) in diabetic rats. Taken together, chronic SAC treatment could ameliorate cognitive deficits in STZ-diabetic rats through modulation of Nrf2/NF-κB/TLR4/HO-1, and acetylcholinesterase and attenuation of associated oxidative stress and neuroinflammation.