Oleandrin: A bioactive phytochemical and potential cancer killer via multiple cellular signaling pathways

Ethnobotany and phytochemistry of plants used to treat musculoskeletal disorders among Skaw Karen, Thailand

CONTEXT

Musculoskeletal system disorders (MSD) are prevalent around the world affecting the health of people, especially farmers who work hard in the field. Karen farmers use many medicinal plants to treat MSD.

OBJECTIVE

This study collects traditional plant-based remedies used by the Skaw Karen to treat MSD and evaluates their active phytochemical compounds.

MATERIALS AND METHODS

The ethnobotanical study was conducted in six Karen villages in Chiang Mai province using semi-structured interviews were of 120 informants. The data were analyzed using ethnobotanical indices including use values (UV), choice value (CV), and informant consensus factor (ICF). Consequently, the 20 most important species, according to the indices, were selected for phytochemical analysis using LC-MS/MS.

RESULTS

A total of 3731 use reports were obtained for 139 species used in MSD treatment. The most common ailments treated with those plants were muscular pain. A total of 172 high-potential active compounds for MSD treatment were identified. Most of them were flavonoids, terpenoids, alkaloids, and steroids. The prevalent phytochemical compounds related to treat MSD were 9-hydroxycalabaxanthone, dihydrovaltrate, morroniside, isoacteoside, lithocholic acid, pomiferin, cucurbitacin E, leonuriside A, liriodendrin, and physalin E. Sambucus javanica Reinw. ex Blume (Adoxaceae), Betula alnoides Buch.-Ham. ex D.Don (Betulaceae), Blumea balsamifera (L.) DC. (Asteraceae), Plantago major L. (Plantaginaceae) and Flacourtia jangomas (Lour.) Raeusch. (Salicaceae) all had high ethnobotanical index values and many active compounds.

DISCUSSION AND CONCLUSIONS

This study provides valuable information, demonstrating low-cost medicine plants that are locally available. It is a choice of treatment for people living in remote areas.

Ameliorative potential of eriocitrin against cadmium instigated hepatotoxicity in rats via regulating Nrf2/keap1 pathway

BACKGROUND

Cadmium (Cd) is a hazardous heavy metal that adversely affects the vital body organs particularly liver. Eriocitrin (ERCN) is a plant-based flavonoid that is well-known for its wide range of pharmacological potential. This research trial was aimed to determine the ameliorative potential of ERCN against Cd provoked hepatotoxicity in rats.

METHODOLOGY

Twenty-four rats (Rattus norvegicus) were apportioned into control, Cd treated (5 mg/kg), Cd (5 mg/kg) + ERCN (25 mg/kg) and only ERCN (25 mg/kg) administrated group. Expressions of Nrf2/Keap1 pathway and apoptotic markers were assessed through qRT-PCR. The levels of inflammatory and liver function markers were evaluated by using standard ELISA kits.

KEY FINDINGS

Cd exposure reduced the expression of Nrf2 and anti-oxidant genes as well as the activity of catalase (CAT), glutathione reductase (GSR), superoxide dismutase (SOD), glutathione peroxidase (GPx), glutathione S-transferase (GST) and glutathione (GSH) contents while escalating the expression of Keap1. Furthermore, Cd intoxication augmented malondialdehyde (MDA) and reactive oxygen species (ROS) levels in hepatic tissues. Exposure to Cd resulted in a notable elevation in the levels of alanine transaminase (ALT), alkaline phosphatase (ALP) and aspartate aminotransferase (AST). Cd administration upregulated nuclear factor-kappa B (NF-κB), interleukin-1 beta (IL-1β), tumor necrosis factor-alpha (TNF-α), and interleukin-6 (IL-6) levels as well as cyclooxygenase-2 (COX-2) activity. Furthermore, Cd administration upsurged Bax and Caspase-3 expression while reducing the expression of Bcl-2. Moreover, Cd intoxication disrupted the normal architecture of hepatic tissues. However, supplementation of ERCN significantly (p < 0.05) ameliorated the aforementioned disruptions induced by Cd intoxication.

CONCLUSION

ERCN treatment remarkably ameliorated the hepatic tissues owing to its antioxidant, anti-inflammatory, and anti-apoptotic potentials. These findings underscore the therapeutic potential of ERCN to counteract the adverse effects of environmental pollutants on hepatic tissues.

Radical scavenging potential of spectrophotometric, spectroscopic, microscopic, and EDX observed zinc oxide nanoparticles from leaves, buds, and flowers extract of Bauhinia Variegata Linn: A thorough comparative insight

The present study incorporated an environment-friendly and cost-efficient green synthesis method for fabricating zinc oxide nanoparticles (ZnO-NPs) using various parts (leaves, buds, and flowers) of Bauhinia Variegate Linn. UV-Spectrophotometric analysis was used to confirm the synthesis of ZnO-NPs, which showed an absorption band within 360-380 nm range. Further techniques like FT-IR spectroscopy and (SEM) scanning electron microscopy equipped with a novel EDX were also included to confirm the synthesis, size, and shape of ZnO-NPs. Results obtained by FT-IR showed that the phytochemicals present in the ethanolic extract successfully acted as a capping agent. SEM micrographs confirmed irregularly shaped nanoparticles with an average size of 70-80 nm. The presence of Zinc and Oxygen peaks in EDX also confirmed the successful synthesis of ZnO nanoparticles. The radical scavenging (antioxidant) potential of prepared nanoparticles was also evaluated by DPPH radical assay. The ZnO-NPs obtained from the ethanolic extract of buds showed the highest %RSA (86%) as compared to the flowers (79%) and leaves (76%). The current study findings showed the versatile morphology of all parts of the plant with significant antioxidant potential, establishing the use of Bauhinia Variegate in biological systems for various biomedical applications. RESEARCH HIGHLIGHTS: A thorough comparative analysis of the radical scavenging power of major parts of the Bauhinia Variegate, which is 1st of its kind. Extensive characterization using UV-Vis spectrophotometry, FT-IR, SEM, and EDX to observe the conformational and morphological changes. Analysis of the reduction potential of leaves, buds, and flowers of a single plant for future directions in green synthesis.

Investigation on the mechanisms by which the herbal remedies induce anti-prostate cancer activity: uncovering the most practical natural compound

Prostate cancer (PCa) is one of the most reported cancers among men worldwide. Targeting the essential proteins associated with PCa could be a promising method for cancer treatment. Traditional and herbal remedies (HRs) are the most practical approaches for PCa treatment. Here, the proteins and enzymes associated with PCa were determined based on the information obtained from the DisGeNET database. The proteins with a gene-disease association (GDA) score greater than 0.7 and the genes that have a disease specificity index (DSI) = 1 were selected as the target proteins. 28 HRs with anti-PCa activity as a traditional treatment for PCa were chosen as potential bioactive compounds. More than 500 compound-protein complexes were screened to find the top-ranked bioactives. The results were further evaluated using the molecular dynamics (MD) simulation and binding free energy calculations. The outcomes revealed that procyanidin B2 3,3'-di-O-gallate (B2G2), the most active ingredient of grape seed extract (GSE), can act as an agonist for PTEN. PTEN has a key role in suppressing PCa cells by applying phosphatase activity and inhibiting cell proliferation. B2G2 exhibited a considerable binding affinity to PTEN (11.643 kcal/mol). The MD results indicated that B2G2 could stabilize the key residues of the phosphatase domain of PTEN and increase its activity. Based on the obtained results, the active ingredient of GSE, B2G2, could play an agonist role and effectively increase the phosphatase activity of PTEN. The grape seed extract is a useful nutrition that can be used in men's diets to inhibit PCa in their bodies.Communicated by Ramaswamy H. Sarma.

Chemoprotective and immunomodulatory potential of Lactobacillus reuteri against cadmium chloride-induced breast cancer in mice

INTRODUCTION

The current study aimed to investigate the role of probiotic Lactobacillus reuteri for the treatment and prevention of breast cancer.

MATERIALS AND METHODS

Breast cancer was induced by using Cadmium Chloride (Cd) (2 mg/kg) in group II. Tamoxifen was administered to group III. Group IV was treated with Lactobacillus reuteri. Group V was treated with Cd for one month and divided into three subgroups including VA, VB, and VC which were treated with tamoxifen, Lactobacillus reuteri, and tamoxifen + Lactobacillus reuteri, respectively.

RESULTS

Significantly higher levels of TNF-α (40.9 ± 4.2 pg/mL), IL-6 (28.0 ± 1.5 pg/mL), IL-10 (60.2 ± 2.0 pg/mL), IFN-γ (60.2 ± 2.0 pg/mL), ALAT (167.2 ± 6.2 U/l), ASAT (451.6 ± 13.9 U/l), and MDA (553.8 ± 19.6 U/l) was observed in Cd group. In comparison, significantly lower levels of TNF-α (18.0 ± 1.1 pg/mL), IL-6 (9.4 ± 0.4 pg/mL), IL-10 (20.8 ± 1.1 pg/mL), IFN-γ (20.8 ± 1.1 pg/mL), ALAT (85.2 ± 3.6 U/l), ASAT (185 ± 6.9 U/l), and MDA (246.0 ± 7.5 U/l) were observed in group Cd + Tam + LR. Liver histopathology of the Cd group showed hemorrhage and ductal aberrations. However, mild inflammation and healthier branched ducts were observed in treatment groups. Furthermore, the renal control group showed normal glomerular tufts, chronic inflammation from the Cd group, and relatively healthier glomerulus with mild inflammation in treatment groups.

CONCLUSION

Hence, the preventive and anticancerous role of probiotic Lactobacillus reuteri is endorsed by the findings of the current study.

Sulforaphane ameliorate Arsenic induced cardiotoxicity in rats: Role of PI3k/Akt mediated Nrf2 signaling pathway

Arsenic (As) toxicity can generate reactive free radicals, which play an important role in the evolution of cardiomyopathy. The aim of this research is to see if sulforaphane (SFN) protects against As-induced heart damage, oxidative stress, and mitochondrial complex dysfunction via the PI3K/Akt/Nrf2 signaling pathway. The rats were placed into four groups, each with eight rats. Group 1: Normal rats (control group); Group 2: Treatment group (5 mg/kg body weight); Group 3: SFN+As-treatment group (80 mg/kg body weight + 5 mg/kg body weight); Group 4: SFN group only (80 mg/kg body weight). The swot will last 4 weeks. At the end of the intermission (28 days), all of the rats starved overnight and killed with cervical decapitation. As administration considerably (p < 0.05) inflated the extent of free radicals (O2-, OH-), lipoid peroxidation (malondialdehyde, 4-hydroxynonenal), lipoid profile (low-density lipoprotein-cholesterol, very low-density lipoprotein-cholesterol (VLDL-C), total cholesterol, triglyceride, and phospholipids), cardiac Troponin (cTnT&I), and Mitochondrial complex III. A noteworthy (p < 0.05) diminish the level of HDL-C, Mitochondrial complex I and II, enzymatic (superoxide dismutase, catalase, and glutathione peroxidase), and nonenzymatic antioxidant (glutathione and total sulfhydryl groups) and PI3k, Akt, and Nrf2 sequence in As treated rats. The western blot, real-time polymerase chain reaction, flowcytometric, and histology studies all corroborated the biochemical findings which revealed significant heart damage in rats. Pretreatment with SFN significantly (p < 0.05) reduced the invitro free radicals, lipid oxidative indicators, mitochondrial complex, lipid profiles, and increased phase II antioxidants in the heart. This result shows that dietary supplementation of SFN protects against As-induced cardiotoxicity via PI3k/Akt/Nrf2 pathway in rats.

A review for cancer treatment with mushroom metabolites through targeting mitochondrial signaling pathway: In vitro and in vivo evaluations, clinical studies and future prospects for mycomedicine

Resistance to apoptosis stands as a roadblock to the successful pharmacological execution of anticancer drug effect. A comprehensive insight into apoptotic signaling pathways and an understanding of the mechanisms of apoptosis resistance are crucial to unveil new drug targets. At this juncture, researchers are heading towards natural sources in particular, mushroom as their potential drugs leads to being the reliable source of potent bioactive compounds. Given the continuous increase in cancer cases, the potent anticancer efficacy of mushrooms has inevitably become a fascinating object to researchers due to their higher safety margin and multitarget. This review aimed to collect and summarize all the available scientific data on mushrooms from their extracts to bioactive molecules in order to suggest their anticancer attributes via a mitochondrion -mediated intrinsic signaling mechanism. Compiled data revealed that bioactive components of mushrooms including polysaccharides, sterols and terpenoids as well as extracts prepared using 15 different solvents from 53 species could be effective in the supportive treatment of 20 various cancers. The underlying therapeutic mechanisms of the studied mushrooms are explored in this review through diverse and complementary investigations: in vitro assays, pre-clinical studies and clinical randomized controlled trials. The processes mainly involved were ROS production, mitochondrial membrane dysfunction, and action of caspase 3, caspase 9, XIAP, cIAP, p53, Bax, and Bcl-2. In summary, the study provides facts pertaining to the potential beneficial effect of mushroom extracts and their active compounds against various types of cancer and is shedding light on the underlying targeted signaling pathways.

Acetyl barlerin from Barleria trispinosa induces chemopreventive NQO1 and attenuates LPS-induced inflammation: in vitro and molecular dynamic studies

Extraction and fractionation of Barleria trispinosa growing in Saudi Arabia yielded four iridoid compounds identified by spectroscopic techniques as acetylbarlerin (1), barlerin (2), shanzhiside methyl ester (3) and 6-⍺-L-rhamnopyranosyl-8-O-acetylshanzihiside methyl ester (4). Preliminary experiments confirmed that compound 1 acts as an inducer of chemopreventive NAD(P)H:Quinone oxidoreductase 1 (NQO1) enzymatic activity in a murine hepatoma (Hepa1c1c7) chemoprevention model. It also demonstrated the ability to inhibit the lipopolysaccharides (LPS)-induced nitric oxide (NO) production in the RAW264.7 macrophage model. Western blotting revealed the ability of compound 1 to up-regulate the protein expression of the NQO1 marker. Furthermore, compound 1 elicited NO suppression in RAW264.7 macrophages by inhibiting iNOS protein expression. Molecular docking and molecular simulation studies of 1 supported its experimental results as an inhibitor of the nuclear factor erythroid 2-Kelch-like ECH-associated protein 1 (Nrf2-KEAP1) complex, resulting in Nrf2-mediated induction of chemopreventive NQO1.Communicated by Ramaswamy H. Sarma.

The potential role of formononetin in cancer treatment: An updated review

Currently, cancer is one of the main research topics, due to its high incidence and drug resistance to existing anti-cancer drugs. Formononetin, a natural product with phytoestrogenic properties and diverse biological functions, has attracted the attention of researchers working on anticancer drugs. Formononetin emerges as an intriguing bioactive substance compared to other isoflavones as it exhibits potent chemotherapeutic activity with less toxicity. Formononetin effectively plays a significant role in inhibiting cell proliferation, invasion, and metastatic abilities of cancer cells by targeting major signaling pathways at the junction of interconnected pathways. It also induces apoptosis and cell cycle arrest by modulating mediator proteins. It causes upregulation of key factors such as p-AKT, p38, p21, and p53 and downregulation of NF-κB. Furthermore, formononetin regulates the neoplastic microenvironment by inactivating the ERK1/2 pathway and lamin A/C signaling and has been reported to inactivate JAK/STAT, PKB or AKT, and mitogen-activated protein kinase pathways and to suppress cell migration, invasion, and angiogenesis in human cancer cells. To assist researchers in further exploring formononetin as a potential anticancer therapeutic candidate, this review focuses on both in vitro and in vivo proof of concept studies, patents, and clinical trials pertinent to formononetin's anticancer properties. Overall, this review discusses formononetin from a comprehensive perspective to highlight its potential benefits as an anticancer agent.

The cross-talk between LncRNAs and JAK-STAT signaling pathway in cancer

Long non-coding RNAs (lncRNAs) are non-coding RNAs that were transcribed from the human genome and have become important regulators in a number of cellular activities, mostly via controlling gene expression. A growing body of evidence shows that lncRNAs regulate various factors to impact various biological activities that are related to tumorigenesis, including the Janus kinase (JAK)-signal transducer and activator of transcription (STAT) pathway. lncRNAs influence the JAK-STAT signaling pathway either by directly targeting or via indirectly modulating other upstream or downstream pathways' components like members of the suppressor of cytokine signaling (SOCS) family, and other genes that regulate cell proliferation, apoptosis, migration, invasion, and epithelial-mesenchymal transition. Furthermore, lncRNAs can act as downstream effectors of the JAK-STAT pathway and mediates tumorigenesis. The relationship between JAK-STAT signaling and lncRNAs differs among various types of cancers. Besides, lncRNAs, as biological molecules, have been shown to play a dual role in either tumorigenesis or tumor suppression in various cancers. In this review, we focus on the reciprocated regulation and functions of lncRNAs and the JAK-STAT signaling pathway in cancer, as well as narrate the latest research progress on this association. A deeper understanding of this correlation may simplify the recognition of potential targets for clinical therapeutics.

COVID-19 Therapeutic Potential of Natural Products

Despite the fact that coronavirus disease 2019 (COVID-19) treatment and management are now considerably regulated, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is still one of the leading causes of death in 2022. The availability of COVID-19 vaccines, FDA-approved antivirals, and monoclonal antibodies in low-income countries still poses an issue to be addressed. Natural products, particularly traditional Chinese medicines (TCMs) and medicinal plant extracts (or their active component), have challenged the dominance of drug repurposing and synthetic compound libraries in COVID-19 therapeutics. Their abundant resources and excellent antiviral performance make natural products a relatively cheap and readily available alternative for COVID-19 therapeutics. Here, we deliberately review the anti-SARS-CoV-2 mechanisms of the natural products, their potency (pharmacological profiles), and application strategies for COVID-19 intervention. In light of their advantages, this review is intended to acknowledge the potential of natural products as COVID-19 therapeutic candidates.

A toxic shrub turned therapeutic: The dichotomy of Nerium oleander bioactivities

Nerium oleander L. is a medicinal plant, used for the treatment of cancers and hyperglycemia across the world, especially in Indian sub-continent, Turkey, Morocco, and China. Although clinical studies supporting its pharmacological effects remain critically underexplored, accidental and intentional consumption of any part of the plant causes fatal toxicity in animals and humans. While the polyphenolic fraction of oleander leaves has been attributed to its pre-clinical pharmacological activities, the presence of diverse cardiac glycosides (especially oleandrin) causes apoptosis to cancer cells in vitro and results in clinical signs of oleander poisoning. Thus, the dual pharmacological and toxicological role of oleander is a perplexing dichotomy in phytotherapy. The current investigative review, therefore, intended to analyze the intrinsic and extrinsic factors that likely contribute to this conundrum. Especially by focusing on gut microbial diversity, abundance, and metabolic functions, oleander-associated pharmacological and toxicological studies have been critically analyzed to define the dual effects of oleander. Electronic databases were extensively screened for relevant research articles (including pre-clinical and clinical) related to oleander bioactivities and toxicity. Taxonomic preference was given to the plant N. oleander L. and synonymous plants as per 'The World Flora Online' database (WCSP record #135196). Discussion on yellow oleander (Cascabela thevetia (L.) Lippold) has intentionally been avoided since it is a different plant. The review indicates that the gut microbiota likely plays a key role in differentially modulating the pharmacological and toxicological effects of oleander. Other factors identified influencing the oleander bioactivities include dose and mode of treatment, cardiac glycoside pharmacokinetics, host-endogenous glycosides, plant material processing and phytochemical extraction methods, plant genotypic variations, environmental effects on the phytochemical quality and quantity, gene expression variations, host dietary patterns and co-morbidity, etc. The arguments proposed are also relevant to other medicinal plants containing toxic cardiac glycosides.

Modulatory effect of caffeic acid in alleviating diabetes and associated complications

Diabetes mellitus (DM) is one of the most common metabolic disorders characterized by elevated blood glucose levels. Prolonged uncontrolled hyperglycemia often leads to multi-organ damage including diabetic neuropathy, nephropathy, retinopathy, cardiovascular disorders, and diabetic foot ulcers. Excess production of free radicals causing oxidative stress in tissues is often considered to be the primary cause of onset and progression of DM and associated complications. Natural polyphenols can be used to induce or inhibit the expression of antioxidant enzymes such as glutathione peroxidase, heme oxygenase-1, superoxide dismutase, and catalase that are essential in maintaining redox balance, and ameliorate oxidative stress. Caffeic acid (CA) is a polyphenolderived from hydroxycinnamic acid and possesses numerous physiological properties includ-ing antioxidant, anti-inflammatory, anti-atherosclerotic, immune-stimulatory, cardioprotective, antiproliferative, and hepatoprotective activities. CA acts as a regulatory compound affecting numerous biochemical pathways and multiple targets. These include various transcription factors such as nuclear factor-B, tumor necrosis factor-α, interleukin-6, cyclooxygenase-2, and nuclear factor erythroid 2-related factor 2. Therefore, this review summarizes the pharmacological properties, molecular mechanisms, and pharmacokinetic profile of CA in mitigating the adverse effects of DM and associated complications. The bioavailability, drug delivery, and clinical trials of CA have also been discussed.

Localized Microsphere/Hydrogel for Tumor Immunotherapy of Cardiac Glycoside with Minimal Toxicity

It has been reported that cardiac glycosides (CGs) commonly used in clinical practice can inhibit tumor growth by inducing immunogenic cell death (ICD), and their positive benefits have been documented in several clinical trials of drug combinations. However, the inherent cardiogenic side effects need to be addressed before CGs can be truly applied in clinical antitumor therapy. In this study, a dual controlled release microsphere/hydrogel platform (OL-M/Gel) was constructed to precisely control the output of oleandrin (OL, one of the representative CGs) in situ in tumors. With the help of this intelligent drug release platform, OL can be released in vitro and in vivo in a sustained and stable manner. The ability of OL to induce ICD and the subsequent antigen presentation and cytotoxic T-cell cascades was first stated, which resulted in potent tumor growth suppression without significant side effects. In addition, the inhibition of autologous tumor recurrence and metastasis by OL-M/Gel was also revealed. This study is expected to break through the inherent bottleneck of CGs and promote their clinical transformation in the field of antitumor treatment.

Drug Repurposing: A New Hope in Drug Discovery for Prostate Cancer

Prostate cancer (PCA), the most common cancer in men, accounted for 1.3 million new incidences in 2018. An increase in incidences is an issue of concern that should be addressed. Of all the reported prostate cancers, 85% were detected in stages III and IV, making them difficult to treat. Conventional drugs gradually lose their efficacy due to the developed resistance against them, thus requiring newer therapeutic agents to be used as monotherapy or combination. Recent research regarding treatment options has attained remarkable speed and development. Therefore, in this context, drug repurposing comes into the picture, which is defined as the "investigation of the off-patent, approved and marketed drugs for a novel therapeutic indication" which saves at least 30% of the time and cost, reducing the cost of treatment for patients, which usually runs high in cancer patients. The anticancer property of cardiac glycosides in cancers was tested in the early 1980s. The trend then shifts toward treating prostate cancer by repurposing other cardiovascular drugs. The current review mainly emphasizes the advantageous antiprostate cancer profile of conventional CVS drugs like cardiac glycosides, RAAS inhibitors, statins, heparin, and beta-blockers with underlying mechanisms.

Natural Products as Anticancer Agents: Current Status and Future Perspectives

Natural products have been an invaluable and useful source of anticancer agents over the years. Several compounds have been synthesized from natural products by modifying their structures or by using naturally occurring compounds as building blocks in the synthesis of these compounds for various purposes in different fields, such as biology, medicine, and engineering. Multiple modern and costly treatments have been applied to combat cancer and limit its lethality, but the results are not significantly refreshing. Natural products, which are a significant source of new therapeutic drugs, are currently being investigated as potential cytotoxic agents and have shown a positive trend in preclinical research and have prompted numerous innovative strategies in order to combat cancer and expedite the clinical research. Natural products are becoming increasingly important for drug discovery due to their high molecular diversity and novel biofunctionality. Furthermore, natural products can provide superior efficacy and safety due to their unique molecular properties. The objective of the current review is to provide an overview of the emergence of natural products for the treatment and prevention of cancer, such as chemosensitizers, immunotherapeutics, combinatorial therapies with other anticancer drugs, novel formulations of natural products, and the molecular mechanisms underlying their anticancer properties.

The Botanical Drug PBI-05204, a Supercritical CO2 Extract of Nerium Oleander, Is Synergistic With Radiotherapy in Models of Human Glioblastoma

Glioblastoma multiforme (GBM) is the most common as well as one of the most malignant types of brain cancer. Despite progress in development of novel therapies for the treatment of GBM, it remains largely incurable with a poor prognosis and a very low life expectancy. Recent studies have shown that oleandrin, a unique cardiac glycoside from Nerium oleander, as well as a defined extract (PBI-05204) that contains this molecule, inhibit growth of human glioblastoma, and modulate glioblastoma patient-derived stem cell-renewal properties. Here we demonstrate that PBI-05204 treatment leads to an increase in vitro in the sensitivity of GBM cells to radiation in which the main mechanisms are the transition from autophagy to apoptosis, enhanced DNA damage and reduced DNA repair after radiotherapy (RT) administration. The combination of PBI-05204 with RT was associated with reduced tumor progression evidenced by both subcutaneous as well as orthotopic implanted GBM tumors. Collectively, these results reveal that PBI-05204 enhances antitumor activity of RT in preclinical/murine models of human GBM. Given the fact that PBI-05204 has already been examined in Phase I and II clinical trials for cancer patients, its efficacy when combined with standard-of-care radiotherapy regimens in GBM should be explored.

Oleandrin: A Systematic Review of its Natural Sources, Structural Properties, Detection Methods, Pharmacokinetics and Toxicology

Oleandrin is a highly lipid-soluble cardiac glycoside isolated from the plant Nerium oleander (Apocynaceae) and is used as a traditional herbal medicine due to its excellent pharmacological properties. It is widely applied for various disease treatments, such as congestive heart failure. Recently, oleandrin has attracted widespread attention due to its extensive anti-cancer and novel anti-viral effects. However, oleandrin has a narrow therapeutic window and exhibits various toxicities, especially typical cardiotoxicity, which is often fatal. This severe toxicity and low polarity have significantly hindered its application in the clinic. This review describes natural sources, structural properties, and detection methods of oleandrin. Based on reported poisoning cases and sporadic animal experiments, the pharmacokinetic characteristics of oleandrin are summarized, so as to infer some possible phenomena, such as enterohepatic circulation. Moreover, the relevant factors affecting the pharmacokinetics of oleandrin are analyzed, and some research approaches that may ameliorate the pharmacokinetic behavior of oleandrin are proposed. With the toxicology of oleandrin being thoroughly reviewed, the development of safe clinical applications of oleandrin may be possible given potential research strategies to decrease toxicity.

Synthesis of Cardiotonic Steroids Oleandrigenin and Rhodexin B

This article describes a concise synthesis of cardiotonic steroids oleandrigenin (7) and its subsequent elaboration into the natural product rhodexin B (2) from the readily available intermediate (8) that could be derived from the commercially available steroids testosterone or DHEA via three-step sequences. These studies feature an expedient installation of the β16-oxidation based on β14-hydroxyl-directed epoxidation and subsequent epoxide rearrangement. The following singlet oxygen oxidation of the C17 furan moiety provides access to oleandrigenin (7) in 12 steps (LLS) and a 3.1% overall yield from 8. The synthetic oleandrigenin (7) was successfully glycosylated with l-rhamnopyranoside-based donor 28 using a Pd(II)-catalyst, and the subsequent deprotection under acidic conditions provided cytotoxic natural product rhodexin B (2) in a 66% yield (two steps).

Caffeic acid and its derivatives as potential modulators of oncogenic molecular pathways: New hope in the fight against cancer

As a phenolic acid compound, caffeic acid (CA) can be isolated from different sources such as tea, wine and coffee. Caffeic acid phenethyl ester (CAPE) is naturally occurring derivative of CA isolated from propolis. This medicinal plant is well-known due to its significant therapeutic impact including its effectiveness as hepatoprotective, neuroprotective and anti-diabetic agent. Among them, anti-tumor activity of CA has attracted much attention, and this potential has been confirmed both in vitro and in vivo. CA can induce apoptosis in cancer cells via enhancing ROS levels and impairing mitochondrial function. Molecular pathways such as PI3K/Akt and AMPK with role in cancer progression, are affected by CA and its derivatives in cancer therapy. CA is advantageous in reducing aggressive behavior of tumors via suppressing metastasis by inhibiting epithelial-to-mesenchymal transition mechanism. Noteworthy, CA and CAPE can promote response of cancer cells to chemotherapy, and sensitize them to chemotherapy-mediated cell death. In order to improve capacity of CA and CAPE in cancer suppression, it has been co-administered with other anti-tumor compounds such as gallic acid and p-coumaric acid. Due to its poor bioavailability, nanocarriers have been developed for enhancing its ability in cancer suppression. These issues have been discussed in the present review with a focus on molecular pathways to pave the way for rapid translation of CA for clinical use.

Saponins in Cancer Treatment: Current Progress and Future Prospects

Saponins are steroidal or triterpenoid glycoside that is distinguished by the soap-forming nature. Different saponins have been characterized and purified and are gaining attention in cancer chemotherapy. Saponins possess high structural diversity, which is linked to the anticancer activities. Several studies have reported the role of saponins in cancer and the mechanism of actions, including cell-cycle arrest, antioxidant activity, cellular invasion inhibition, induction of apoptosis and autophagy. Despite the extensive research and significant anticancer effects of saponins, there are currently no known FDA-approved saponin-based anticancer drugs. This can be attributed to a number of limitations, including toxicities and drug-likeness properties. Recent studies have explored options such as combination therapy and drug delivery systems to ensure increased efficacy and decreased toxicity in saponin. This review discusses the current knowledge on different saponins, their anticancer activity and mechanisms of action, as well as promising research within the last two decades and recommendations for future studies.

Cardiac Glycosides as Immune System Modulators

Cardiac glycosides (CGs) are natural steroid compounds occurring both in plants and animals. They are known for long as cardiotonic agents commonly used for various cardiac diseases due to inhibition of Na⁺/K⁺-ATPase (NKA) pumping activity and modulating heart muscle contractility. However, recent studies show that the portfolio of diseases potentially treatable with CGs is much broader. Currently, CGs are mostly studied as anticancer agents. Their antiproliferative properties are based on the induction of multiple signaling pathways in an NKA signalosome complex. In addition, they are strongly connected to immunogenic cell death, a complex mechanism of induction of anticancer immune response. Moreover, CGs exert various immunomodulatory effects, the foremost of which are connected with suppressing the activity of T-helper cells or modulating transcription of many immune response genes by inhibiting nuclear factor kappa B. The resulting modulations of cytokine and chemokine levels and changes in immune cell ratios could be potentially useful in treating sundry autoimmune and inflammatory diseases. This review aims to summarize current knowledge in the field of immunomodulatory properties of CGs and emphasize the large area of potential clinical use of these compounds.

Cardamonin inhibits the progression of oesophageal cancer by inhibiting the PI3K/AKT signalling pathway

Background: Oesophageal cancer is the most common malignant tumour with a poor prognosis, and the current treatment methods are limited. Therefore, identifying effective treatment methods has become a research hotspot. Cardamonin (CAR) is a natural chalcone compound and has been reported to play an anticancer role in several cancers. However, its function in oesophageal cancer and the possible underlying mechanism are still unclear. The purpose of this study was to demonstrate the anticancer effect of CAR on oesophageal cancer in vivo and in vitro and to explore the underlying mechanism.

Materials and Methods: MTT, crystal violet, and colony formation assays were used to detect oesophageal cancer cell proliferation. The effects of CAR on oesophageal cancer cell migration and invasion were detected by wound healing assay and Transwell assay. Hoechst 33258 staining and flow cytometry were used to detect cell apoptosis. Protein expression levels were detected by Western blot. A tumour xenograft model was established to further test the effect of CAR on the growth of oesophageal cancer in vivo.

Results: The results showed that CAR inhibited the proliferation, migration, and invasion of oesophageal cancer cells in a concentration-dependent manner and induced apoptosis. Furthermore, the Western blot assay showed that CAR could suppress metastasis by inhibiting epithelial-mesenchymal transition (EMT) as indicated by downregulated expression of the mesenchymal markers N-cadherin and vimentin, the EMT transcription factor Snail, and matrix metalloproteinases (MMPs) and upregulated expression of the epithelial marker E-cadherin. CAR was associated with upregulation of the pro-apoptotic proteins Bax and Bad and downregulation of the anti-apoptotic protein Bcl-2 and triggered the mitochondrial apoptosis pathway, which in turn promoted caspase-3 activation and subsequent cleavage of PARP; however, the mitochondria-related apoptotic effects induced by CAR were blocked by caspase inhibitor Z-VAD-FMK pretreatment, which prevented programmed cell death triggered by CAR. In addition, CAR reduced the phosphorylation level of downstream effector molecules of phosphatidylinositol 3 kinase (PI3K) in a dose-dependent manner, and treatment with the PI3K agonist 740Y-P could partially reverse the anticancer effect of CAR, demonstrating that CAR played an antitumour role by inhibiting the PI3K/AKT signalling pathway in oesophageal cancer cells. Moreover, the EC9706 xenograft model further confirmed that CAR can significantly inhibit tumour growth in vivo.

Conclusion: In summary, CAR exhibited a strong anticancer effect on human oesophageal cancer cells and promoted apoptosis by inhibiting the PI3K/AKT signalling pathway, suggesting that CAR can be used as new strategy for oesophageal cancer treatment.

Toxicity of herbal medications suggested as treatment for COVID-19: A narrative review

OBJECTIVES

In the absence of a definitive cure, herbal medications are gaining increasing popularity in the general public for treatment of coronavirus disease 2019 (COVID-19). Although many herbal preparations are safe and can be used without complication, serious toxicities do occur. This article focuses on the major characteristics and toxicities of herbal preparations that have been proposed as treatments for COVID-19.

METHODS

A review was performed focusing on herbal preparations that have gained popularity as potential treatments for COVID-19. Some of these preparations have been directly recommended by government agencies, whereas others have gained popularity through various other news sources.

RESULTS

The herbal preparations covered in this paper include the cardiac glycoside oleandrin, plants of the Datura genus, and herbs commonly used in traditional Chinese Medicine including plants of the Aconitum genus, bitter apricot seeds, ephedra, and licorice root.

CONCLUSION

Although herbal preparations have been reported to aid in the treatment of COVID-19 with success, few clinical trials have been performed to evaluate their efficacy and instead rely mainly on in vitro studies and anecdotal reports. Furthermore, many of the herbal preparations suggested carry significant toxicities, and frontline healthcare workers should be aware of the common symptoms and toxidromes that result from these poisonings.

Oleandrin, a cardiac glycoside, induces immunogenic cell death via the PERK/elF2α/ATF4/CHOP pathway in breast cancer

Chemotherapeutic agents have been linked to immunogenic cell death (ICD) induction that is capable of augmenting anti-tumor immune surveillance. The cardiac glycoside oleandrin, which inhibits Na⁺/K⁺-ATPase pump (NKP), has been shown to suppress breast cancer growth via inducing apoptosis. In the present study, we showed that oleandrin treatment triggered breast cancer cell ICD by inducing calreticulin (CRT) exposure on cell surface and the release of high-mobility group protein B1 (HMGB1), heat shock protein 70/90 (HSP70/90), and adenosine triphosphate (ATP). The maturation and activation of dendritic cells (DCs) were increased by co-culturing with the oleandrin-treated cancer cells, which subsequently enhanced CD8⁺ T cell cytotoxicity. Murine breast cancer cell line EMT6 was engrafted into BALB/c mice, and tumor-bearing mice were administered with oleandrin intraperitoneally every day. Oleandrin inhibited tumor growth and increased tumor infiltrating lymphocytes including DCs and T cells. Furthermore, the differential mRNA expression incurred by oleandrin was investigated by mRNA sequencing and subsequently confirmed by quantitative real-time polymerase chain reaction (qRT-PCR) and western blotting. Mechanistically, oleandrin induced endoplasmic reticulum (ER) stress-associated, caspase-independent ICD mainly through PERK/elF2α/ATF4/CHOP pathway. Pharmacological and genetic inhibition of protein kinase R-like ER kinase (PERK) suppressed oleandrin-triggered ICD. Taken together, our findings showed that oleandrin triggered ER stress and induced ICD-mediated immune destruction of breast cancer cells. Oleandrin combined with immune checkpoint inhibitors might improve the efficacy of immunotherapy.

Dual relationship between long non-coding RNAs and STAT3 signaling in different cancers: New insight to proliferation and metastasis

Uncontrolled growth and metastasis of cancer cells is an increasing challenge for overcoming cancer, and improving survival of patients. Complicated signaling networks account for proliferation and invasion of cancer cells that need to be elucidated for providing effective cancer therapy, and minimizing their malignancy. Long non-coding RNAs (lncRNAs) are RNA molecules with a length of more than 200 nucleotides. They participate in cellular events, and their dysregulation in a common phenomenon in different cancers. Noteworthy, lncRNAs can regulate different molecular pathways, and signal transducer and activator of transcription 3 (STAT3) is one of them. STAT3 is a tumor-promoting factors in cancers due to its role in cancer proliferation (cell cycle progression and apoptosis inhibition) and metastasis (EMT induction). LncRNAs can function as upstream mediators of STAT3 pathway, reducing/enhancing its expression. This dual relationship is of importance in affecting proliferation and metastasis of cancer cells. The response of cancer cells to therapy such as chemotherapy and radiotherapy is regulated by lncRNA/STAT3 axis. Tumor-promoting lncRNAs including NEAT1, SNHG3 and H19 induces STAT3 expression, while tumor-suppressing lncRNAs such as MEG3, PTCSC3 and NKILA down-regulate STAT3 expression. Noteworthy, upstream mediators of STAT3 such as microRNAs can be regulated by lncRNAs. These complicated signaling networks are mechanistically described in the current review.

Antiviral Effects of Oleandrin

Over the past 15 years, investigators have reported on the utility and safety of cardiac glycosides for numerous health benefits including those as treatments for malignant disease, stroke-mediated ischemic injury and certain neurodegenerative diseases. In addition to those, there is a growing body of evidence for novel antiviral effects of selected cardiac glycoside molecules. One unique cardiac glycoside, oleandrin derived from Nerium oleander, has been reported to have antiviral activity specifically against 'enveloped' viruses including HIV and HTLV-1. Importantly, a recent publication has presented in vitro evidence for oleandrin's ability to inhibit production of infectious virus particles when used for treatment prior to, as well as after infection by SARS-CoV-2/COVID-19. This review will highlight the known in vitro antiviral effects of oleandrin as well as present previously unpublished effects of this novel cardiac glycoside against Ebola virus, Cytomegalovirus, and Herpes simplex viruses.

Cytotoxicity of Oleandrin Is Mediated by Calcium Influx and by Increased Manganese Uptake in Saccharomyces cerevisiae Cells

Oleandrin, the main component of Nerium oleander L. extracts, is a cardiotoxic glycoside with multiple pharmacological implications, having potential anti-tumoral and antiviral characteristics. Although it is accepted that the main mechanism of oleandrin action is the inhibition of Na⁺/K⁺-ATPases and subsequent increase in cell calcium, many aspects which determine oleandrin cytotoxicity remain elusive. In this study, we used the model Saccharomyces cerevisiae to unravel new elements accounting for oleandrin toxicity. Using cells expressing the Ca²⁺-sensitive photoprotein aequorin, we found that oleandrin exposure resulted in Ca²⁺ influx into the cytosol and that failing to pump Ca²⁺ from the cytosol to the vacuole increased oleandrin toxicity. We also found that oleandrin exposure induced Mn²⁺ accumulation by yeast cells via the plasma membrane Smf1 and that mutants with defects in Mn²⁺ homeostasis are oleandrin-hypersensitive. Our data suggest that combining oleandrin with agents which alter Ca²⁺ or Mn²⁺ uptake may be a way of controlling oleandrin toxicity.