Preliminary investigation of the safe dose of oleandrin when administered orally to Beagles

OBJECTIVE

The purpose of the study reported herein was to determine the dose of oleander extract and oleandrin (the key pharmacologically active constituent) that could be safely administered PO to dogs.

ANIMALS

42 purebred Beagle dogs were used to study an extract of Nerium oleander.

METHODS

3 studies were performed in 42 purebred young adult (ages 12 months or older) Beagle dogs using a supercritical fluid extract of N oleander leaves. The first study was an 8-day initial dose-ranging study in 2 dogs, a second 7-day repeat-dosing study was performed in 4 dogs, and the final study was performed in 32 dogs where test subjects were given extract or placebo once daily for 28 consecutive days via oral (gavage) administration followed by a 14-day recovery period.

RESULTS

At 2.3 µg/kg of oleandrin, there were no observable adverse effects during the duration of the study. Adverse effects were not seen until doses exceeded 6.9 µg/kg of oleandrin, at which time mild, reversible clinical signs were noted. However, a dose > 460 µg of oleandrin/kg was fatal in 1 of 2 dogs in this study.

CLINICAL RELEVANCE

The studies reported here, taken in totality, suggest that doses exceeding 6.9 µg/kg of oleandrin may be associated with cardiac abnormalities. An estimated no treatment effective adverse event oral dose of oleandrin appears to be 4.6 µg of oleandrin/kg. Higher doses may be tolerable but should be used with appropriate monitoring.

Poisoning by Nerium oleander L. in Franconia Geese

This study describes the acute poisoning of four 3-month-old Franconia geese (Anser anser) by oleander plants (Nerium oleander). After the accidental ingestion of oleander clippings, the geese exhibited a rapid onset of severe symptoms, leading to mortality within 15-90 min. Necropsy revealed cardiac and renal lesions. Specifically, interstitial edema, red blood cell infiltration, and myofibril loss were observed in the cardiac muscle, and tubular epithelial degeneration, interstitial edema, and hemorrhages were evident in the kidneys. Oleandrin, a glycoside with cardiac effects, was detected in the liver, kidneys, heart, brain, and muscles. The clinical implications underscore the urgency of veterinary intervention upon oleander ingestion, and the specific findings contribute valuable insights into the pathological effects of acute oleander poisoning in geese, aiding veterinarians in prompt diagnosis and treatment.

Fatal poisoning due to ingestion of boiled oleander leaf extract

Nerium oleander is an ornamental evergreen shrub belonging to the family Apocynaceae. The Apocynaceae family includes the attractive evergreen shrub known as oleander. The cardiotoxic glycoside, oleandrin, is present in all portions of the common oleander plant. Oleander consumption can result in deadly situations accidentally or as a suicide attempt. After consuming kettle-boiled oleander leaf extract as part of a suicide attempt, an 80-year-old man was discovered comatose in his home and taken to our emergency room. The patient's heart rate was 30 beats per minute, and he had hypotension. Arterial blood gas analysis revealed remarkable metabolic acidosis and hyperkalemia (K: 7.7 mEq/L). An electrocardiogram showed a wide QRS wave, similar to a sine curve. The patient collapsed following cardiac arrest soon after hospital arrival. Veno-arterial extracorporeal membrane oxygenation was initiated; however, the patient eventually died. The serum level of oleandrin at hospital arrival, subsequently measured by LC-MS/MS, was found to be 33.4 ng/mL, far above the levels reported in previous fatal cases.

A suicide attempt by ingestion of oleander leaves and treatment with digoxin-specific Fab antibody fragments

Natural cardiac glycosides have positive inotropic heart effects but at high, toxic doses they can cause life-threatening cardiac arrhythmias. Here we present the first Croatian case of a 16-year-old girl who attempted suicide by eating dried oleander leaves, which contain natural cardiac glycosides, and her treatment with a specific antidote. The girl presented with an oedema of the uvula indicating local toxicity, severe bradycardia, first-degree atrioventricular block, drowsiness, and vomiting. Having taken her medical history, we started treatment with atropine, intravenous infusion of dextrose-saline solution and gastroprotection, but it was not successful. Then we introduced digoxin-specific Fab antibody fragments and within two hours, the patient's sinus rhythm returned to normal. Cases of self-poisoning with this oleander are common in South-East Asia, because it is often used as a medicinal herb, and digoxin-specific Fab fragments have already been reported as effective antidote against oleander poisoning there. Our case has taught us that it is important to have this drug in the hospital pharmacy both for digitalis and oleander poisoning.

Differential Activities of the Botanical Extract PBI-05204 and Oleandrin on Innate Immune Functions under Viral Challenge Versus Inflammatory Culture Conditions

The Nerium oleander extract PBI 05204 (PBI) and its cardiac glycoside constituent oleandrin have direct anti-viral properties. Their effect on the immune system, however, is largely unknown. We used an in vitro model of human peripheral blood mononuclear cells to document effects under three different culture conditions: normal, challenged with the viral mimetic polyinosinic:polycytidylic acid Poly I:C, and inflamed by lipopolysaccharide (LPS). Cells were evaluated for immune activation marks CD69, CD25, and CD107a, and culture supernatants were tested for cytokines. Both PBI and oleandrin directly activated Natural Killer (NK) cells and monocytes and triggered increased production of cytokines. Under viral mimetic challenge, PBI and oleandrin enhanced the Poly I:C-mediated immune activation of monocytes and NK cells and enhanced production of IFN-γ. Under inflammatory conditions, many cytokines were controlled at similar levels as in cultures treated with PBI and oleandrin without inflammation. PBI triggered higher levels of some cytokines than oleandrin. Both products increased T cell cytotoxic attack on malignant target cells, strongest by PBI. The results show that PBI and oleandrin directly activate innate immune cells, enhance anti-viral immune responses through NK cell activation and IFN-γ levels, and modulate immune responses under inflamed conditions. The potential clinical impact of these activities is discussed.

Quantitative evaluation of cardiac glycosides and their seasonal variation analysis in Nerium oleander using UHPLC-ESI-MS/MS

INTRODUCTION

Nerium oleander is an eminent source of structurally diverse cardiac glycosides (CGs), plays a prominent role in the treatment of heart failure, and inhibits the proliferation of cancer cell lines. CGs exert their cardiotonic action by binding to the extracellularly exposed recognition sites on Na⁺ /K⁺ -ATPase, an integral membrane protein that establishes the electrochemical gradient of Na⁺ and K⁺ ions across the plasma membrane.

OBJECTIVE

We aimed to quantitatively determine CGs and their seasonal variation in leaf and stem samples of N. oleander utilizing UHPLC-ESI-MS/MS techniques.

METHODS

The UHPLC-ESI-MS/MS analytical method was developed utilizing multiple reaction monitoring (MRM) mode. The Waters BEH C18 (150 mm × 2.1 mm, 1.7 μm) column was used with a 22-min linear gradient consisting of acetonitrile and 5 mM ammonium acetate buffer.

RESULTS

In total 21 CGs were quantitatively determined in the seasonal leaf and stem samples of N. oleander along with the absolute quantitation of the three chemical markers odoroside H (244.8 μg/g), odoroside A (231.4 μg/g), and oleandrin (703.9 μg/g). The season-specific accumulation of chemical markers was observed in the order of predominance odoroside A (summer season, stem), odoroside H (winter season, stem), and oleandrin (rainy season, leaf). Besides this, the remaining 18 CGs were relatively quantified in the same samples.

CONCLUSION

The developed method is simple and reliable and can be used for the identification and quantification of multiple CGs in N. oleander.

Efficacy of oleandrin and PBI-05204 against bovine viruses of importance to commercial cattle health

Background

Bovine viral diarrhea virus (BVDV), bovine respiratory syncytial virus (BRSV). and bovine coronavirus (BCV) threaten the productivity of cattle worldwide. Development of therapeutics that can control the spread of these viruses is an unmet need. The present research was designed to explore the in vitro antiviral activity of the Nerium oleander derived cardiac glycoside oleandrin and a defined N. oleander plant extract (PBI-05204) containing oleandrin.

Methods

Madin Darby Bovine Kidney (MDBK) cells, Bovine Turbinate (BT) cells, and Human Rectal Tumor-18 (HRT-18) cells were used as in vitro culture systems for BVDV, BRSV and BCV, respectively. Cytotoxicity was established using serial dilutions of oleandrin or PBI-05204. Noncytotoxic concentrations of each drug were used either prior to or at 12 h and 24 h following virus exposure to corresponding viruses. Infectious virus titers were determined following each treatment.

Results

Both oleandrin as well as PBI-05204 demonstrated strong antiviral activity against BVDV, BRSV, and BCV, in a dose-dependent manner, when added prior to or following infection of host cells. Determination of viral loads by PCR demonstrated a concentration dependent decline in virus replication. Importantly, the relative ability of virus produced from treated cultures to infect new host cells was reduced by as much as 10,000-fold at noncytotoxic concentrations of oleandrin or PBI-05204.

Conclusions

The research demonstrates the potency of oleandrin and PBI-05204 to inhibit infectivity of three important enveloped bovine viruses in vitro. These data showing non-toxic concentrations of oleandrin inhibiting infectivity of three bovine viruses support further investigation of in vivo antiviral efficacy.

New Cardenolides from Biotransformation of Gitoxigenin by the Endophytic Fungus Alternaria eureka 1E1BL1: Characterization and Cytotoxic Activities

Microbial biotransformation is an important tool in drug discovery and for metabolism studies. To expand our bioactive natural product library via modification and to identify possible mammalian metabolites, a cytotoxic cardenolide (gitoxigenin) was biotransformed using the endophytic fungus Alternaria eureka 1E1BL1. Initially, oleandrin was isolated from the dried leaves of Nerium oleander L. and subjected to an acid-catalysed hydrolysis to obtain the substrate gitoxigenin (yield; ~25%). After 21 days of incubation, five new cardenolides 1, 3, 4, 6, and 8 and three previously- identified compounds 2, 5 and 7 were isolated using chromatographic methods. Structural elucidations were accomplished through 1D/2D NMR, HR-ESI-MS and FT-IR analysis. A. eureka catalyzed oxygenation, oxidation, epimerization and dimethyl acetal formation reactions on the substrate. Cytotoxicity of the metabolites were evaluated using MTT cell viability method, whereas doxorubicin and oleandrin were used as positive controls. Biotransformation products displayed less cytotoxicity than the substrate. The new metabolite 8 exhibited the highest activity with IC₅₀ values of 8.25, 1.95 and 3.4 µM against A549, PANC-1 and MIA PaCa-2 cells, respectively, without causing toxicity on healthy cell lines (MRC-5 and HEK-293) up to concentration of 10 µM. Our results suggest that A. eureka is an effective biocatalyst for modifying cardenolide-type secondary metabolites.

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.

Classical Drug Digitoxin Inhibits Influenza Cytokine Storm, With Implications for Covid-19 Therapy

BACKGROUND/AIM

Influenza viruses, corona viruses and related pneumotropic viruses cause sickness and death partly by inducing cytokine storm, a hyper-proinflammatory host response by immune cells and cytokines in the host airway. Based on our in vivo experience with digitoxin as an inhibitor of TNFα-driven NFĸB signaling for cytokine expression in prostate cancer in rats and in cystic fibrosis in humans, we hypothesize that this drug will also block a virally-activated cytokine storm. Materials Methods: Digitoxin was administered intraperitoneally to cotton rats, followed by intranasal infection with 107TCID50/100 g of cotton rat with influenza strain A/Wuhan/H3N2/359/95. Daily digitoxin treatment continued until harvest on day 4 of the experiment.

RESULTS

The cardiac glycoside digitoxin significantly and differentially suppressed levels of the cytokines TNFα, GRO/KC, MIP2, MCP1, and IFNγ, in the cotton rat lung in the presence of influenza virus.

CONCLUSION

Since cytokine storm is a host response, we suggest that digitoxin may have a therapeutic potential not only for influenza and but also for coronavirus infections.

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.

Development and Validation of a UHPLC-ESI-MS/MS Method for Quantification of Oleandrin and Other Cardiac Glycosides and Evaluation of Their Levels in Herbs and Spices from the Belgian Market

Cardiac glycosides (CGs) are naturally occurring plant secondary metabolites that can be toxic to humans and animals. The aim of this work was to develop a targeted analytical method utilizing liquid chromatography-tandem mass spectrometry (LC-MS/MS) for quantification of these plant toxins in a herbal-based food and human urine. The method included oleandrin, digoxin, digitoxin, convallatoxin, and ouabain. Samples of culinary herbs were extracted with acetonitrile and cleaned using Oasis® MAX solid-phase extraction (SPE), while samples of urine were diluted with acidified water and purified on Oasis® HLB SPE cartridges. Limits of quantification were in the range of 1.5-15 ng/g for herbs and 0.025-1 ng/mL for urine. The mean recovery of the method complied with the acceptable range of 70-120% for most CGs, and relative standard deviations were at maximum 14% and 19% for repeatability and reproducibility, respectively. Method linearity was good with calculated R² values above 0.997. The expanded measurement uncertainty was estimated to be in the range of 7-37%. The LC-MS/MS method was used to examine 65 samples of culinary herbs and herb and spice mixtures collected in Belgium, from supermarkets and local stores. The samples were found to be free from the analyzed CGs.

AnvirzelTMregulates cell death through inhibiting GSK-3 activity in human U87 glioma cells

Objectives: Cardiac glycosides are used as potential anti-cancer agents due to their effects on the inhibition of proliferation and induction of apoptosis and/or autophagy in cancer cells. Herein, we aimed to study the potential signaling pathways taken role in differential cell-death properties of Anvirzel^TM which is consisted of two toxic cardiac glycosides (oleandrin and oleandrigenin), in U87 human glioblastoma cells.Methods: The anti-proliferative and anti-migratory effects of Anvirzel^TM were assessed in U87 cells by WST-1 assay and wound healing assay, respectively. After treatment of Anvirzel^TMwith doses of 10, 25, 50, 100 and 250 μg/ml, expression levels of proteins related to cell death were investigated by Western blot.Results: Anvirzel™ markedly inhibited the growth of U87 cells in a time- and dose-dependent manner following 24 h and 48 h treatments (p < 0.05). In addition, it was found that Anvirzel™ inhibited GSK-3, NOS and HIF1-α expressions whereas activated ERK in U87 cells compared to vehicle (p < 0.05).Discussion: The results suggested that Anvirzel^TM regulated cell death distinctly from apoptosis in human glioblastoma cells. Further studies are required for validation of mechanistic insights about the potential signaling pathways taken role in differential cell death properties of Anvirzel^TM.

Neuroprotective effects of mitoquinone and oleandrin on Parkinson's disease model in zebrafish

Aim: The aim of this study is to investigate the possible protective effects of mitoquinone and oleandrin on rotenone induced Parkinson's disease in zebrafish. Materials and methods: Adult zebrafish were exposed to rotenone and mitoquinone for 30 days. Biochemical parameters were determined by spectrophotometric method and Parkinson's disease-related gene expressions were determined by reverse transcription polymerase chain reaction method. Measurement of neurotransmitters was performed by liquid chromatography tandem-mass spectrometry instrument. The accumulation of synuclein was demonstrated by immunohistochemical staining. In vitro thiazolyl blue tetrazolium bromide method was applied to determine the mitochondrial function of synaptosomal brain fractions using rotenone as a neurotoxic agent and mitoquinone and oleandrin as neuroprotective agents. Results: Mitoquinone improved the oxidant-antioxidant balance and neurotransmitter levels that were disrupted by rotenone. Mitoquinone also ameliorated the expressions of Parkinson's disease-related gene expressions that were disrupted by rotenone. According to thiazolyl blue tetrazolium bromide assay results, mitoquinone and oleandrin increased mitochondrial function which was decreased due to rotenone exposure. Conclusion: Based on the results of our study, positive effects of mitoquinone were observed in Parkinson's disease model induced by rotenone in zebrafish.

Oleandrin and Its Derivative Odoroside A, Both Cardiac Glycosides, Exhibit Anticancer Effects by Inhibiting Invasion via Suppressing the STAT-3 Signaling Pathway

The cardiac glycosides oleandrin and odoroside A, polyphenolic monomer compounds extracted from Nerium oleander, have been found to have antitumor effects on various tumors at low doses. However, the mechanisms of anticancer effects of oleandrin and odoroside A are not well known. Therefore, in this study, we aimed to investigate the anticancer effects of oleandrin and odoroside A and their associated mechanisms in highly metastatic MDA-MB-231 breast cancer cells and radiotherapy-resistant (RT-R) MDA-MB-231 cells. Our results showed that oleandrin and odoroside A dose-dependently decreased the colony formation and the invasion of both cell lines at nanomolar ranges. Furthermore, oleandrin (50 nM) and odoroside A (100 nM) reduced octamer-binding transcription factor 3/4 (OCT3/4) and β-catenin levels and matrix metalloproteinase-9 (MMP-9) activity. Finally, we found that phospho-STAT-3 levels were increased in MDA-MB-231 and RT-R-MDA-MB-231, but not in endothelial cells (ECs), and that the levels were significantly decreased by oleandrin (50 nM) and odoroside A (100 nM). Inhibition of phospho-signal transducer and activator of transcription (STAT)-3 significantly reduced OCT3/4 and β-catenin levels and MMP-9 activity, ultimately resulting in reduced invasion. These results suggest that the anticancer effects of oleandrin and odoroside A might be due to the inhibition of invasion through of phospho-STAT-3-mediated pathways that are involved in the regulation of invasion-related molecules.

Oleandrin induces DNA damage responses in cancer cells by suppressing the expression of Rad51

Oleandrin is a monomeric compound extracted from leaves and seeds of Nerium oleander. It had been reported that oleandrin could effectively inhibit the growth of human cancer cells. However, the specific mechanisms of the oleandrin-induced anti-tumor effects remain largely unclear. Genomic instability is one of the main features of cancer cells, it can be the combined effect of DNA damage and tumour-specific DNA repair defects. DNA damage plays important roles during tumorigenesis. In fact, most of the current chemotherapy agents were designed to kill cancer cells by inducing DNA damage. In this study, we found that oleandrin was effective to induce apoptosis in cancer cells, and cause rapid DNA damage response, represented by nuclear RPA (Replication Protein A, a single strand DNA binding protein) and γH2AX(a marker for DNA double strand breaks) foci formation. Interestingly, expression of RAD51, a key protein involved in homologous recombination (HR), was suppressed while XRCC1 was up-regulated in oleandrin treated cancer cells. These results suggested that XRCC1 may play a predominant role in repairing oleandrin-induced DNA damage. Collectively, oleandrin may be a potential anti-tumor agent by suppressing the expression of Rad51.

The Glycoside Oleandrin Reduces Glioma Growth with Direct and Indirect Effects on Tumor Cells

Oleandrin is a glycoside that inhibits the ubiquitous enzyme Na⁺/K⁺-ATPase. In addition to its known effects on cardiac muscle, recent in vitro and in vivo evidence highlighted its potential for anticancer properties. Here, we evaluated for the first time the effect of oleandrin on brain tumors. To this aim, mice were transplanted with human or murine glioma and analyzed for tumor progression upon oleandrin treatment. In both systems, oleandrin impaired glioma development, reduced tumor size, and inhibited cell proliferation. We demonstrated that oleandrin does the following: (1) enhances the brain-derived neurotrophic factor (BDNF) level in the brain; (2) reduces both microglia/macrophage infiltration and CD68 immunoreactivity in the tumor mass; (3) decreases astrogliosis in peritumoral area; and (4) reduces glioma cell infiltration in healthy parenchyma. In BDNF-deficient mice (bdnftm1Jae/J) and in glioma cells silenced for TrkB receptor expression, oleandrin was not effective, indicating a crucial role for BDNF in oleandrin's protective and antitumor functions. In addition, we found that oleandrin increases survival of temozolomide-treated mice. These results encourage the development of oleandrin as possible coadjuvant agent in clinical trials of glioma treatment.SIGNIFICANCE STATEMENT In this work, we paved the road for a new therapeutic approach for the treatment of brain tumors, demonstrating the potential of using the cardioactive glycoside oleandrin as a coadjuvant drug to standard chemotherapeutics such as temozolomide. In murine models of glioma, we demonstrated that oleandrin significantly increased mouse survival and reduced tumor growth both directly on tumor cells and indirectly by promoting an antitumor brain microenvironment with a key protective role played by the neurotrophin brain-derived neurotrophic factor.

Regulation of Intrinsic and Extrinsic Apoptotic Pathways in Osteosarcoma Cells Following Oleandrin Treatment

Our previous study has reported the anti-tumor effect of oleandrin on osteosarcoma (OS) cells. In the current study, we mainly explored its potential regulation on intrinsic and extrinsic apoptotic pathway in OS cells. Cells apoptosis, reactive oxygen species (ROS) and mitochondrial membrane potential (MMP) were detected using fluorescence staining and flow cytometry. Caspase-3 activity was detected using a commercial kit. The levels of cytoplasmic cytochrome c, mitochondrial cytochrome c, bcl-2, bax, caspase-9, Fas, FasL, caspase-8 and caspase-3 were detected by Western blotting. z-VAD-fmk was applied to block both intrinsic and extrinsic apoptosis pathways, and cells apoptosis was also tested. Furthermore, we used z-LEHD-fmk and Fas blocking antibody to inhibit intrinsic and extrinsic pathways, separately, and the selectivity of oleandrin on these pathways was explored. Results showed that oleandrin induced the apoptosis of OS cells, which was accompanied by an increase in ROS and a decrease in MMP. Furthermore, cytochrome c level was reduced in mitochondria but elevated in the cytoplasm. Caspase-3 activity was enhanced by oleandrin in a concentration- and time-dependent manner. Oleandrin also down-regulated the expression of bcl-2, but up-regulated bax, caspase-9, Fas, FasL, caspase-8 and caspase-3. In addition, the suppression of both apoptotic pathways by z-VAD-fmk greatly reverted the oleandrin-induced apoptosis. Moreover, the suppression of one pathway by a corresponding inhibitor did not affect the regulation of oleandrin on another pathway. Taken together, we concluded that oleandrin induced apoptosis of OS cells via activating both intrinsic and extrinsic apoptotic pathways.

Pharmacological aspects of Nerium indicum Mill: A comprehensive review

Phytomedicine is the oldest medical practice known to man. Since the dawn of mankind, various plant resources are used to cure different diseases and also for a long and healthy life. The ancient knowledge of plant based medicine has transferred from generations to generations and accumulated as ethnopharmacological knowledge among different ethnic groups. India is the spanning bed of traditional phytomedicinal system where Ayurveda was born out of the knowledge of traditional medicine. In various other countries of South-Eastern Asia, South America, and in Arabian countries, still today, a great number of people rely primarily on phytomedicines to cure diseases. In the complementary and alternative medicinal systems, Nerium indicum is one such plant which is famed for its therapeutic efficiency in different diseases globally. In the present time, when the pharmaceutical companies are concentrating more toward the plant based traditional medicines to avoid the side-effects and resistance against synthetic drugs, N. indicum has proved its efficiency in different disease models. Therefore, this review comprehensively covers the medicinal and pharmacological activities of different parts of the plant N. indicum.

Oleandrin: A cardiac glycosides with potent cytotoxicity

Cardiac glycosides are used in the treatment of congestive heart failure and arrhythmia. Current trend shows use of some cardiac glycosides in the treatment of proliferative diseases, which includes cancer. Nerium oleander L. is an important Chinese folk medicine having well proven cardio protective and cytotoxic effect. Oleandrin (a toxic cardiac glycoside of N. oleander L.) inhibits the activity of nuclear factor kappa-light-chain-enhancer of activated B chain (NF-κB) in various cultured cell lines (U937, CaOV3, human epithelial cells and T cells) as well as it induces programmed cell death in PC3 cell line culture. The mechanism of action includes improved cellular export of fibroblast growth factor-2, induction of apoptosis through Fas gene expression in tumor cells, formation of superoxide radicals that cause tumor cell injury through mitochondrial disruption, inhibition of interleukin-8 that mediates tumorigenesis and induction of tumor cell autophagy. The present review focuses the applicability of oleandrin in cancer treatment and concerned future perspective in the area.

Cellular location and expression of Na+, K+ -ATPase α subunits affect the anti-proliferative activity of oleandrin

The purpose of this study was to investigate whether intracellular distribution of Na(+), K(+) -ATPase α3 subunit, a receptor for cardiac glycosides including oleandrin, is differentially altered in cancer versus normal cells and whether this altered distribution can be therapeutically targeted to inhibit cancer cell survival. The cellular distribution of Na(+), K(+) -ATPase α3 isoform was investigated in paired normal and cancerous mucosa biopsy samples from patients with lung and colorectal cancers by immunohistochemical staining. The effects of oleandrin on α3 subunit intracellular distribution, cell death, proliferation, and EKR phosphorylation were examined in differentiated and undifferentiated human colon cancer CaCO-2 cells. While Na(+), K(+) -ATPase α3 isoform was predominantly located near the cytoplasmic membrane in normal human colon and lung epithelia, the expression of this subunit in their paired cancer epithelia was shifted to a peri-nuclear position in both a qualitative and quantitative manner. Similarly, distribution of α3 isoform was also shifted from a cytoplasmic membrane location in differentiated human colon cancer CaCO-2 cells to a peri-nuclear position in undifferentiated CaCO-2 cells. Intriguingly, oleandrin exerted threefold stronger anti-proliferative activity in undifferentiated CaCO-2 cells (IC50, 8.25 nM) than in differentiated CaCO-2 cells (IC50, >25 nM). Oleandrin (10 to 20 nM) caused an autophagic cell death and altered ERK phosphorylation in undifferentiated but not in differentiated CaCO-2 cells. These data demonstrate that the intracellular location of Na(+), K(+) -ATPase α3 isoform is altered in human cancer versus normal cells. These changes in α3 cellular location and abundance may indicate a potential target of opportunity for cancer therapy.