Potential role and therapeutic implications of glutathione peroxidase 4 in the treatment of Alzheimer's disease

Alzheimer's disease is an age-related neurodegenerative disorder with a complex and incompletely understood pathogenesis. Despite extensive research, a cure for Alzheimer's disease has not yet been found. Oxidative stress mediates excessive oxidative responses, and its involvement in Alzheimer's disease pathogenesis as a primary or secondary pathological event is widely accepted. As a member of the selenium-containing antioxidant enzyme family, glutathione peroxidase 4 reduces esterified phospholipid hydroperoxides to maintain cellular redox homeostasis. With the discovery of ferroptosis, the central role of glutathione peroxidase 4 in anti-lipid peroxidation in several diseases, including Alzheimer's disease, has received widespread attention. Increasing evidence suggests that glutathione peroxidase 4 expression is inhibited in the Alzheimer's disease brain, resulting in oxidative stress, inflammation, ferroptosis, and apoptosis, which are closely associated with pathological damage in Alzheimer's disease. Several therapeutic approaches, such as small molecule drugs, natural plant products, and non-pharmacological treatments, ameliorate pathological damage and cognitive function in Alzheimer's disease by promoting glutathione peroxidase 4 expression and enhancing glutathione peroxidase 4 activity. Therefore, glutathione peroxidase 4 upregulation may be a promising strategy for the treatment of Alzheimer's disease. This review provides an overview of the gene structure, biological functions, and regulatory mechanisms of glutathione peroxidase 4, a discussion on the important role of glutathione peroxidase 4 in pathological events closely related to Alzheimer's disease, and a summary of the advances in small-molecule drugs, natural plant products, and non-pharmacological therapies targeting glutathione peroxidase 4 for the treatment of Alzheimer's disease. Most prior studies on this subject used animal models, and relevant clinical studies are lacking. Future clinical trials are required to validate the therapeutic effects of strategies targeting glutathione peroxidase 4 in the treatment of Alzheimer's disease.

Natural products as a crucial source of anti-inflammatory drugs: recent trends and advancements

Natural active molecules are key sources of modern innovative drugs. Particularly, a great amount of natural active molecules have been reported to possess promising therapeutic effects on inflammatory diseases, including asthma, rheumatoid arthritis, hepatitis, enteritis, metabolic disorders and neurodegenerative diseases. However, these natural active molecules with various molecular structures usually exert anti-inflammatory effects through diversiform pharmacological mechanisms, which is necessary to be summarized systematically. In this review, we introduced the current major anti-inflammatory natural active molecules based on their chemical structures, and discussed their pharmacological mechanisms including anti-inflammatory molecular signaling pathways and potential target proteins, which providing a referential significance on the development of novel anti-inflammatory drugs, and also revealing new therapeutic strategies for inflammatory diseases.

Inhibitory Effect of 5-Adenylic Acid on Bitter Taste of Antipsychotic Drugs

The purpose of the present study was to examine the effect of adenylic acid (adenosine 5-monophosphate;AMP), a known nutritional enhancer, on inhibiting the bitterness of antipsychotic medicines administered to patients with mental illnesses, including children. First, we chose four antipsychotic medicines, amitriptyline hydrochloride (AMT), chlorpromazine hydrochloride (CPZ), haloperidol (HPD) and risperidone (RIS) and evaluated the inhibition of their bitterness by AMP through taste sensor measurements. AMP showed a significant bitterness inhibition effect on all drugs. Second, MarvinSketch analysis revealed the potential formation of electrostatic interactions between ionic forms (IV) of AMP and ionic (cationic) forms of each drug, which resulted in bitterness suppression. Third, chemical shift perturbations in 1H-NMR studies suggested an interaction between the phosphate group of AMP and amino group of AMT, CPZ, HPD and RIS. Last, conventional elution experiments of up to 1 min simulating oral cavity conditions were performed for 1 whole AMT tablet, half AMT tablet, crushed half AMT tablet, and crushed AMT tablet containing AMP powder/solution (1, 3 mM potency). The taste sensor output values of the crushed AMT tablet containing AMP powder/solution (1, 3 mM potency) were significantly lower than those of the crushed tablet.

Recent Advances of Bioactive Marine Natural Products in Drug Discovery

Marine natural products(MNPs)are valuable resources for drug development.To date,17 drugs from marine sources are in clinical use,and 33 pharmaceutical compounds are in clinical trials.Presently the success of drug development from the marine resources is higher than the industry average.It is a feasible strategy to conduct the discovery of druglead compounds based on marine chemical ecology by fully exploiting the pharmacological potential of marine chemical defense matters.In the search for bioactive MNPs,our group has constructed a biological resources library including more than 1500 strains of fungi.Focusing on the strategy of Blue Drug Library,we have discovered a series of novel MNPs with abundant biological functions.Highly efficient and scalable total synthesis of(+)-aniduquinolone A(44)and pesimquinolone I(48)have been completed,which will facilitate access to sufficient quantities of candidates for in vivo pharmacological and toxicological studies.As a nucleoprotein(NP)inhibitor,QLA(75)possesses significant anti-influenza A virus(IAV)activities both in vitro and in vivo.CHNQD-00803(76)is a potent and selective AMP-activated kinase(AMPK)activator that can effectively inhibit metabolic disorders and metabolic dysfunction-associated steatohepatitis(MASH)progression.Moreover,we identified two new candidate molecules with potent anti-hepatocellular carcinoma effects.Particularly,as a natural guanine-nucleotide exchange factors for ADP-ribosylation factor GTPases(Arf-GEFs)inhibitor prodrug,CHNQD-01255(78)is qualified to be developed as a targeted candidate anticancer drug,which may be promising to apply for cancer immunotherapy.Hence,it is evident that MNPs play an important role in drug development.

Rapid discovery of a novel “green” and natural GST inhibitor for sensitizing hepatocellular carcinoma to Cisplatin by visual screening strategy

Over-expression of glutathione S-transferase(GST)can promote Cisplatin resistance in hepatocellular carcinoma(HCC)treatment.Hence,inhibiting GST is an attractive strategy to improve Cisplatin sensitivity in HCC therapy.Although several synthesized GST inhibitors have been developed,the side effects and narrow spectrum for anticancer seriously limit their clinical application.Considering the abundance of natural compounds with anticancer activity,this study developed a rapid fluorescence technique to screen“green”natural GST inhibitors with high specificity.The fluorescence assay demonstrated that schisanlactone B(hereafter abbreviated as C1)isolated from Xue tong significantly down-regulated GST levels in Cisplatin-resistant HCC cells in vitro and in vivo.Importantly,C1 can selectively kill HCC cells from normal liver cells,effectively improving the therapeutic effect of Cisplatin on HCC mice by downregulating GST expression.Considering the high GST levels in HCC patients,this compound demonstrated the high potential for sensitizing HCC therapy in clinical practice by down-regulating GST levels.

On resource survey of natural mineral drugs in eastern Jilin and their sustaining application

There are rich natural resources of natural mineral drugs in eastern Jilin Province. Systematic resource investigation can elevate fractional conversion of this area' s mineral drugs resources superiority. Research on natural mineral drugs of this area can upgrade the translation rate of resource superiority and accelerate the development of local medical industry, especially, it can provide scientific data for founding the strategic design of Chinese traditional medicine's trademark of Jilin Changbai Mountain. Since the resource of mineral drugs can not be regenerated, it must be exploited scientifically, utilized reasonably and protected effectively its sustaining application.

Current status of drug therapy for alveolar echinococcosis

Alveolar echinococcosis(AE)is a chronic zoonotic parasitic disease caused by infection with Echinococcus multilocularis.AE is associated with a high mortality rate and poses a significant threat to human health.The primary treatment for AE is surgical resection of the lesions;however,owing to its long incubation period and insidious disease progression,many patients are diagnosed only after the onset of complications such as liver cirrhosis,jaundice,and portal hypertension,which preclude curative surgical intervention.For patients who are unwilling or unable to undergo surgery,lifelong administration of anti-AE medications is necessary.Benzimidazole compounds,such as albendazole and mebendazole,are the current mainstays of treatment,offering good efficacy.Nevertheless,these medications primarily inhibit parasite proliferation rather than eradicate the infection,and their long-term use can lead to significant drug-related toxic effects.Consequently,there is an urgent need to develop new therapeutic strategies that convey better efficacy and reduce the adverse effects associated with current treatments.Recent advancements in AE therapy include novel synthetic compounds such as antiviral agents,antibiotics,antineoplastic agents,immunosuppressants,and antiangiogenic agents,as well as natural compounds derived from traditional Chinese and Tibetan medicine.These new drugs show promising clinical potential because they interfere with parasitic metabolic pathways and cellular structures.This review aims to discuss recent research on AE drug therapy,including mechanisms of action,dosing regimens,signalling pathways,and therapeutic outcomes,with a goal of providing new insights and directions for the development of anti-AE drugs and summarizing current advancements in AE pharmacotherapy.

To Speed up the Development and Industrialization of Natural Drugs in China

1.The Current Situation Facing China's accession to the WTO,our pharmaceutical industries must prepare to meet extremely strong competition,because 97% of the synthetic medicines and antibiotics marketed in the country are copies of foreign products.

Current Perspective in the Discovery of Anti-aging Agents from Natural Products

Aging is a process characterized by accumulating degenerative damages,resulting in the death of an organism ultimately.The main goal of aging research is to develop therapies that delay age-related diseases in human.Since signaling pathways in aging of Caenorhabditis elegans(C.elegans),fruit flies and mice are evolutionarily conserved,compounds extending lifespan of them by intervening pathways of aging may be useful in treating age-related diseases in human.Natural products have special resource advantage and with few side effect.Recently,many compounds or extracts from natural products slowing aging and extending lifespan have been reported.Here we summarized these compounds or extracts and their mechanisms in increasing longevity of C.elegans or other species,and the prospect in developing antiaging medicine from natural products.

Naturally derived anti-hepatitis B virus agents and their mechanism of action

Despite that some approved drugs and genetically engineered vaccines against hepatitis B virus(HBV)are available for HBV patients,HBV infection is still a severe public health problem in the world.All the approved therapeutic drugs(including interferonalpha and nucleoside analogues)have their limitations.No drugs or therapeutic methods can cure hepatitis B so far.Therefore,it is urgently needed to discover and develop new anti-HBV drugs,especially nonnucleoside agents.Naturally originated compounds with enormous molecular complexity and diversity offer a great opportunity to find novel anti-HBV lead compounds with specific antiviral mechanisms.In this review,the natural products against HBV are discussed according to their chemical classes such as terpenes,lignans,phenolic acids,polyphenols,lactones,alkaloids and flavonoids.Furthermore,novel mode of action or new targets of some representative anti-HBV natural products are also discussed.The aim of this review is to report new discoveries and updates pertaining to anti-HBV natural products in the last 20years,especially novel skeletons and mode of action.Although many natural products with various skeletons have been reported to exhibit potent anti-HBV effects to date,scarcely any of them are found in the list of conventional anti-HBV drugs worldwide.Additionly,in anti-HBV mechanism of action,only a few references reported new targets or novel mode of action of antiHBV natural products.

miR-15b-5p targeting amyloid precursor protein is involved in the anti-amyloid eflect of curcumin in swAPP695-HEK293 cells

Curcumin exerts a neuroprotective effect on Alzheimer’s disease;however,it is not known whether microRNAs are involved in this protective effect.This study was conducted using swAPP695-HEK293 cells as an Alzheimer’s disease cell model.swAPP695-HEK293 cells were treated with 0,0.5,1,2,5,and 10μM curcumin for 24 hours.The changes in miR-15b-5p,miR-19a-3p,miR-195-5p,miR-101-3p,miR-216b-5p,miR-16-5p and miR-185-5p expression were assessed by real-time quantitative polymerase chain reaction.The mRNA and protein levels of amyloid precursor protein,amyloid-β40 and amyloid-β42 were evaluated by quantitative real-time polymerase chain reaction,western blot assays and enzyme-linked immunosorbent assays.swAPP695-HEK293 cells were transfected with miR-15b-5p mimic,or treated with 1μM curcumin 24 hours before miR-15b-5p inhibitor transfection.The effects of curcumin on amyloid precursor protein,amyloid-β40 and amyloid-β42 levels were evaluated by western blot assays and enzyme-linked immunosorbent assay.Luciferase assays were used to analyze the interaction between miR-15b-5p and the 3′-untranslated region of amyloid precursor protein.The results show that amyloid precursor protein and amyloid-βexpression were enhanced in swAPP695-HEK293 cells compared with HEK293 parental cells.Curcumin suppressed the expression of amyloid precursor protein and amyloid-βand up-regulated the expression of miR-15b-5p in swAPP695-HEK293 cells.In addition,we found a negative association of miR-15b-5p expression with amyloid precursor protein and amyloid-βlevels in the curcumin-treated cells.Luciferase assays revealed that miR-15b-5p impaired the luciferase activity of the plasmid harboring the 3′-untranslated region of amyloid precursor protein.These findings indicate that curcumin down-regulates the expression of amyloid precursor protein and amyloid-βin swAPP695-HEK293 cells,which was partially mediated by miR-15b-5p via targeting of the 3′-untranslated region of amyloid precursor protein.

The Success of Natural Products in Drug Discovery

Drug discovery leading to robust and viable lead candidates’ remains a challenging scientific task, which is the transition from a screening hit to a drug candidate, requires expertise and experience. Natural products and their derivatives have been recognized for many years as a source of therapeutic agents and of structural diversity. However, in addition to their chemical structure diversity and their biodiversity, the development of new technologies has revolutionized the screening of natural products in discovering new drugs. Applying these technologies compensates for the inherent limitations of natural products and offers a unique opportunity to re-establish natural products as a major source for drug discovery. The present article attempts to describe the utilization of compounds derived from natural resources as drug candidates, with a focus on the success of these resources in the process of finding and discovering new and effective drug compounds, an approach commonly referred to as “natural product drug discovery”.

Perspectives and challenges of tropical medicinal herbs and modern drug discovery in the current scenario

Tropical diseases such as malaria, tuberculosis, trypanosomiasis, and leishmaniasis, account for a large number of deaths annually. Herbs are an excellent source of tropical medicines. Many advancements and discoveries have taken place in the field of drug discovery but still, a major population of tropical diseases relies on herbal traditional medicine. There are some challenges related to policy implementation, efficacy, resistance and toxicity of tropical medicines. There are many tropical diseases such as such as schistosomiasis, leishmaniasis, African sleeping sickness, filariasis and chagas disease which are neglected because very few pharmaceutical companies have shown their interest in developing therapeutics against these diseases of poor people. There are many benefits associated with herbal medicine such as the cost of production, patient tolerance, large scale availability, efficacy, safety, potency, recyclability, and environment friendly. A large number of natural extracts such as curcumin, artemisinin, morphine, reserpine, and hypericin, are in use for treatment of different tropical diseases for a long time. The current review is to discuss the overview of tropical medicinal herbs, its scope and limitations in the modern drug discovery process.

Usefulness and limitations of taste sensors in the evaluation of palatability and taste-masking in oral dosage forms

The purpose of this review is to discuss the advantages and limitations of taste sensors in the evaluation of the taste of palatability of different oral dosage forms. First, we consider some ways in which the palatability of various pharmaceutical formulations including orally disintegrating tablets(ODTs) are tested using two different taste sensors. Second, we focus on the evaluation of palatability of ODTs. We compare the usefulness of three pieces of apparatus for estimating the disintegration time of ODTs. Finally, we compare the characteristics of the two taste sensors in the evaluation of palatability of various kinds of drug formulations.

Natural Compound Curcumin—a Channel Potentiator Rather Than a Corrector of the Defective Intracellular Processing of △F508 Mutant Cystic Fibrosis Transmembrane Conductance Regulator

Cystic fibrosis（CF） is a severe genetic disease caused by the gene mutation of the cystic fibrosis transmembrane conductance regulator（CFTR） chloride channel. The most common point mutation AF508, which leads to impaired intracellular processing and channel gating of CFTR, appears in about 90% CF patients. The natural compound curcumin was reported to correct the processing defect of AF508-CFTR and proposed as a potential therapeutic drug to cure CF. In the present study, we analyzed the effect of curcumin on AF508-CFTR and demonstrated that curcumin can restore the impaired chloride conductance of AF508 mutant CFTR. The activity is rapid, reversible and cAMP-dependent. However, we couldn＇t reproduce the previously reported correction of the defective membrane trafficking of AF508-CFTR by curcumin. Therefore, curcumin may not be a superior lead compound for developing anti-CF drugs.

Control of autoimmune arthritis by herbal extracts and their bioactive components

Autoimmune diseases such as rheumatoid arthritis (RA) cause significant morbidity and loss of productivity. Many potent conventionally used drugs are available for these diseases, but their prolonged use is accompanied by severe adverse effects besides a high cost.Therefore, there is an unmet need for effective but less expensive medications for RA and other autoimmune diseases. Natural plant products belonging to the traditional systems of medicine, such as the traditional Chinese medicine and Indian Ayurvedic medicine, offer a vast and promising resource in this regard. However, herbal medicinal products are often poorly characterized for their composition as well as mechanisms of action. We review here the results of our systematically performed studies aimed at defining the anti-arthritic activity of three herbal extracts, namely, modified Huo-luo-xiao-ling dan (HLXL), Celastrus aculeatus Merr., and polyphenolic fraction of green tea (Camellia sinensis), as well as a purifiedcompound Celastrol, a bioactive component of Celastrus. Specifically, we examined the effects of these herbal products on the immunological, biochemical and molecular biological effector pathways in autoimmune arthritis. We have also reviewed here related studies on these herbal products by other investigators. Taken together, we suggest further testing of these herbal products in RA patients.

Anticancer drug screening of natural products:In vitro cytotoxicity assays,techniques,and challenges

Natural products include several diverse compounds that have been found to be effective against cancer.Discovering anticancer compounds in nature is a multistep and complex process that requires pre-clinical and clinical studies.Only a few of the available natural products are used to treat cancer since most of them have very high complexity and low bioavailability.Therefore,the process of anticancer drug discovery requires a straightforward and effective method to assess anticancer activity using in vitro assays.This review summarizes various cell-based assays and techniques used to measure cell viability,migration,and apoptosis,focusing in particular on the principles,mechanisms,advantages,and disadvantages of each assay to provide a preliminary platform for cancer drug discovery.

Marine natural product lepadin A as a novel inducer of immunogenic cell death via CD91-dependent pathway

Immunogenic Cell Death(ICD)represents a mechanism of enhancing T cell-driven response against tumor cells.The process is enabled by release of damage-associated molecular patterns(DAMPs)and cytokines by dying cells.Based on molecular studies and clinical marker assessment,ICD can be a new target for cancer chemotherapy hitherto restricted to a few conventional anticancer drugs.In view of the development of small molecules in targeted cancer therapy,we reported the preliminary evidence on the role of the natural product lepadin A(1)as a novel ICD inducer.Here we describe the ICD mechanism of lepadin A(1)by proving the translocation of the protein calreticulin(CRT)to the plasma membrane of human A2058 melanoma cells.CRT exposure is an ICD marker in clinical studies and was associated with the activation of the intrinsic apoptotic pathway in A2058 cells with lepadin A(1).After the treatment,the tumour cells acquired the ability to activate dendritic cells(DCs)with cytokine release and costimulatory molecule expression that is consistent with a phenotypic profile committed to priming T lymphocytes via a CD91-dependent mechanism.The effect of lepadin A(1)was dose-dependent and comparable to the response of the chemotherapy drug doxorubicin(2),a well-established ICD inducer.

Exploring of drug leads from diversity-oriented Michael-acceptor library derived from natural products

A potential strategy for drug lead identification and in-active natural products re-discovery is elaborated.Starting from fifteen structurally diverse natural products,a focused library featured by Michael acceptors is constructed with IBX mediated oxidation.Biological assay on five tumor cell lines indicates that four Michael acceptors,8a,11a,12a,14a,are with improved cytotoxicity(3-10 folds more potent than the parent compounds),which merit further investigations.Further thiol-sensitive assay of the active hit 8a revealed that it was an irreversible Michael acceptor.The results suggest that the strategy is not only effective and relatively high discovery rate(28%),but also resource saving.

Recommended Medicinal Plants as Source of Natural Products:A Review

Natural product is one of the sources of drugs in pharmaceutical industry,and one of the notable origin of natural product is the medicinal plants.Medicinal plants tend to cure some certain diseases and could be a source for potential drugs.The Department of Health of the Philippines approved 10 medicinal plants namely Allium sativum(Garlic/Bawang),Blumea balsamifera(Nagal camphor/sambong),Cassia alata(Ringworm bush/akapulko),Clinopodium douglasii(Mint/yerba Buena),Ehretia microphylla(Scorpion bush/Tsaang Gubat),Momordica charantia(Bitter Melon/Ampalaya),Peperomia pellucida(Silver bush/ulasimang Bato),Psidium guajava(Guava/Bayabas),Quisqualis indica(Rangoon creeper/niyug-niyogan),and Vitex negundo(Five-leaved Chaste Tree/lagundi).The review was conducted to show that these medicinal plants are capable in treating infections and some diseases.It was found that Allium sativum for the treatmet of wounds,hypertension and tootache;Blumea balsimifera is effective in diuretic treatment for hypertension;Cassia alata for the treatment of scabies,fungal infection,athlete’s foot,tinea flava,ringworm;Clinopodium douglasii for the treatment of muscle pain,arthritis,rheumatism,cough,headache;Ehretia microphylla for the treatment of diarrhea and stomachache;Momordica charantia for the treatment of diabetes mellitus;Peperomia pellucida for the treatment of gout and rheumatism;Psidium guajava for the treatment of wounds and diarrhea;Quisqualis indica for anti-helmintic medicine;and Vitex negundo for the treatment of cough,asthma,and fever.In conclusion,these 10 medicinal plants have natural products that can be used as source for potential drugs.However,there are still many species of ethnobotanical plants that are not yet investigated thoroughly and might be a source for potential drugs.Therefore,more investigations should be done in other species of plant,most especially for the plants with practical used.