What is oleandrin and where does it come from?

Oleandrin is the primary bioactive cardiac glycoside extracted from the leaves and seeds of Nerium oleander, an ornamental shrub native to the Mediterranean, Middle East, and South Asia. It was first chemically isolated in 1861 and is classified as a cardenolide glycoside (C32H48O9) with high lipid solubility, enabling it to cross biological membranes efficiently. The compound is responsible for both the pharmacological properties and the well-documented toxicity of N. oleander.

Is oleandrin effective against cancer?

Preclinical evidence from cell line and animal studies shows oleandrin inhibits tumor growth in pancreatic, breast, lung, prostate, colon, and melanoma models by suppressing NF-κB, PI3K/Akt/mTOR, and STAT-3 signaling pathways. Pharmaceutical formulations PBI-05204 and Anvirzel have entered Phase I and Phase II clinical trials in advanced solid tumor patients at an investigational dose of approximately 0.2255 mg/kg/day, but no completed trial has published definitive efficacy data such as survival benefit or objective response rates. The anticancer evidence remains preliminary and is not sufficient to support oleandrin's use outside of supervised clinical trials.

How toxic is oleandrin and can it kill you?

Oleandrin is highly toxic with a very narrow margin between potentially active and lethal doses; it inhibits the Na+/K+-ATPase pump, causing intracellular calcium overload that can result in fatal ventricular arrhythmias, bradycardia, and cardiac arrest. Poisoning cases from accidental ingestion of N. oleander leaves—even small amounts such as a single leaf in children—have been documented as lethal, and the plant is considered one of the more dangerous ornamental species in toxicology. There is no established safe dose for general human consumption, and oleandrin is not approved as a dietary supplement by any major regulatory agency.

What drug interactions does oleandrin have?

Although formal pharmacokinetic drug interaction studies in humans are lacking, oleandrin is expected to produce dangerous additive cardiotoxicity when combined with other cardiac glycosides such as digoxin, antiarrhythmic drugs (e.g., amiodarone, quinidine), calcium channel blockers, or medications that alter potassium or magnesium levels such as loop diuretics. Hypokalemia from any cause dramatically increases sensitivity to glycoside toxicity. Anyone using cardiovascular medications should have zero exposure to oleandrin outside of a closely monitored clinical trial setting.

What is PBI-05204 and how does it relate to oleandrin?

PBI-05204 is a pharmaceutical-grade supercritical CO2 extract of Nerium oleander leaves standardized to contain oleandrin as its primary active constituent, developed by Phoenix Biotechnology Inc. for oncological applications. It has been studied in Phase I and Phase II clinical trials targeting advanced solid tumors, pancreatic cancer, and other malignancies, with the mechanism of action attributed primarily to oleandrin's inhibition of the Akt/mTOR signaling pathway in cancer cells. PBI-05204 differs from raw plant extracts in its controlled oleandrin content and formulation for parenteral or oral investigational administration, but it remains an experimental agent without regulatory approval for therapeutic use.

What is the current clinical trial status for oleandrin-based cancer treatments?

PBI-05204, a standardized oleandrin extract, has advanced to Phase II clinical trials for pancreatic cancer and other solid tumors, with ongoing research evaluating its efficacy and safety profile in human subjects. Clinical development focuses on determining optimal dosing regimens and identifying patient populations most likely to benefit from oleandrin therapy. The progression from preclinical to clinical testing represents a significant milestone in translating oleandrin's laboratory-demonstrated anticancer mechanisms into therapeutic applications.

What populations should avoid oleandrin supplementation?

Oleandrin should be avoided by pregnant and nursing women due to its cardioactive and potentially teratogenic properties, and by individuals with cardiac arrhythmias, heart disease, or those taking cardiac glycosides or antiarrhythmic medications. Children should not use oleandrin without explicit medical supervision given its narrow safety margin and toxicity risk. Patients with kidney or liver disease may have impaired clearance of oleandrin and should avoid supplementation entirely.

How does oleandrin's mechanism of action compare to conventional chemotherapy drugs?

Unlike many conventional chemotherapy agents that work primarily through DNA damage, oleandrin inhibits specific cellular signaling pathways (PI3K/Akt/mTOR and NF-κB) that control tumor cell survival and proliferation, offering a potentially more targeted mechanism. This pathway-selective approach may result in different toxicity profiles and resistance patterns compared to traditional cytotoxic chemotherapy. Research suggests oleandrin may complement conventional treatments, though direct comparative clinical efficacy studies in humans remain limited.

Oleandrin

Oleandrin is a lipid-soluble cardiac glycoside that exerts anticancer, antiviral, and anti-inflammatory effects primarily through inhibition of the Na+/K+-ATPase pump and downstream suppression of NF-κB, PI3K/Akt/mTOR, and STAT-3 signaling pathways. Phase I/II clinical trials of oleander-derived formulations (Anvirzel, PBI-05204) in advanced solid tumors have explored a suggested dose of 0.2255 mg/kg/day, demonstrating preliminary anticancer activity via Akt/mTOR inhibition, though no completed trials with definitive efficacy endpoints have been published.

Category: Compound Evidence: 1/10 Tier: Preliminary

Origin & History

Oleandrin is the principal cardiac glycoside isolated from Nerium oleander, an evergreen shrub native to the Mediterranean basin, the Middle East, and South Asia, now naturalized across subtropical and tropical regions worldwide. The plant thrives in dry, rocky, well-drained soils with full sun exposure and is commonly cultivated as an ornamental hedge in coastal and arid environments. First chemically isolated in 1861, oleandrin is concentrated primarily in the leaves and seeds of N. oleander, where it serves as a natural defensive phytotoxin against herbivores.

Historical & Cultural Context

Nerium oleander has been recognized as both a medicinal and toxic plant for millennia, with references to its properties appearing in ancient Mesopotamian, Greek, and Roman texts, where it was used cautiously for skin conditions, heart ailments, and as a rodenticide. In traditional South Asian (Ayurvedic) and Mediterranean herbal systems, the plant known as 'Kaner' (Hindi) or 'Defla' (Arabic) was applied in highly diluted preparations for congestive heart failure, skin disorders, and as an emmenagogue, with practitioners aware of its lethal potential at higher doses. Oleandrin itself was first chemically isolated and characterized in 1861, predating the formal understanding of cardiac glycoside pharmacology, and its structural and functional similarities to digitalis glycosides were later established. Modern pharmaceutical interest was revived in the late 20th and early 21st centuries through the development of standardized extracts (Anvirzel, PBI-05204) specifically for oncological applications, representing a translation of traditional cardiotonic use into targeted cancer pharmacology.

Health Benefits

- **Anticancer Activity**: Oleandrin inhibits PI3K/Akt/mTOR and NF-κB pathways, reducing tumor cell proliferation and inducing apoptosis via caspase cascade activation; preclinical studies show anti-proliferative effects in pancreatic, breast, lung, prostate, colon, and melanoma cancer models.
- **Anti-inflammatory Effects**: By blocking NF-κB nuclear translocation downstream of Na+/K+-ATPase inhibition, oleandrin suppresses pro-inflammatory cytokine production and reduces chronic inflammatory signaling implicated in tumor progression.
- **Antiviral Properties**: Oleandrin disrupts virological synapses and impairs viral envelope glycoprotein incorporation, with demonstrated activity against HTLV-1 and exploratory evidence against SARS-CoV-2 in cell-based assays.
- **Apoptosis Induction**: Oleandrin activates intrinsic apoptotic pathways by modulating MAPK signaling and p70S6K activity, promoting programmed cell death selectively in transformed cell lines in vitro.
- **Immune Modulation**: Preclinical data suggest oleandrin enhances natural killer (NK) cell activity and elevates IFN-γ levels, potentially augmenting anti-tumor immune surveillance.
- **Antioxidant Capacity**: Hydroalcoholic leaf extracts of N. oleander containing oleandrin demonstrate measurable antioxidant activity, with an IC50 of 896.9 µg/ml (equivalent to 10.93 µg/ml ascorbic acid) in DPPH radical scavenging assays.
- **FGF-2 Pathway Suppression**: Oleandrin has been shown to reduce fibroblast growth factor-2 (FGF-2) secretion from tumor cells, potentially limiting angiogenesis and tumor microenvironment support in preclinical models.

How It Works

Oleandrin's primary molecular mechanism involves competitive inhibition of the Na+/K+-ATPase (sodium-potassium pump) on cell membranes, disrupting intracellular ion homeostasis and triggering downstream signaling cascades that suppress NF-κB activation, thereby reducing transcription of pro-survival and pro-inflammatory genes. This ion pump inhibition also activates caspase-dependent apoptotic pathways and modulates MAPK signaling, further diminishing tumor cell viability. Concurrently, oleandrin suppresses the PI3K/Akt/mTOR and STAT-3 axes, reducing phosphorylation of key kinases (including p70S6K and Akt) that drive cell proliferation, survival, and immune evasion in malignant cells. Its antiviral mechanism operates distinctly by interfering with virological synapse formation and blocking the incorporation of viral envelope glycoproteins into budding virions, as demonstrated in HTLV-1 and preliminary SARS-CoV-2 studies.

Scientific Research

The clinical evidence base for oleandrin is limited and preliminary; the majority of mechanistic data derives from in vitro cell line experiments and in vivo rodent tumor models rather than controlled human trials. Oleander-derived pharmaceutical formulations—Anvirzel (aqueous extract) and PBI-05204 (supercritical CO2 extract)—have progressed to Phase I and Phase II oncology trials targeting advanced solid tumors, breast, lung, prostate, colon, pancreatic cancers, and melanoma, but published results with quantified endpoints such as hazard ratios, objective response rates, or survival data are not available in the peer-reviewed literature as of the current evidence review. A Phase II suggested dose of 0.2255 mg/kg/day was derived from Phase I dose-escalation work, indicating the studies established preliminary safety and pharmacokinetic parameters rather than definitive efficacy. Independent toxicological and pharmacokinetic characterization studies are explicitly recommended by researchers, and no systematic reviews or meta-analyses of clinical oleandrin data currently exist.

Clinical Summary

Clinical investigation of oleandrin has been conducted through its formulated derivatives, primarily PBI-05204 and Anvirzel, in Phase I and Phase II trials for advanced solid malignancies. These trials established preliminary tolerability data and a candidate dose of 0.2255 mg/kg/day, focusing on Akt/mTOR pathway modulation as a pharmacodynamic biomarker. No published trial has reported statistically significant improvement in overall survival, progression-free survival, or objective tumor response rates with sufficient sample sizes to draw firm conclusions. Confidence in oleandrin's clinical efficacy remains very low; further randomized controlled trials with pre-specified endpoints and adequate statistical power are required before any therapeutic recommendation can be made.

Nutritional Profile

Oleandrin is a pharmacologically active phytochemical, not a nutrient, and does not contribute meaningful macronutrients, vitamins, or dietary minerals in any realistic supplemental context. As a cardenolide cardiac glycoside (molecular formula C32H48O9, MW ~576.7 g/mol), it is highly lipid-soluble, facilitating absorption across biological membranes with inferred enterohepatic circulation suggested by poisoning case pharmacokinetics. The parent plant N. oleander contains co-occurring phytochemicals including quercetin, rutin, chlorogenic acid, ursolic acid, α-tocopherol, and additional cardiac glycosides (neritaloside, odoroside H, oleandrigenin, digitoxigenin), which may contribute to the observed antioxidant and anti-inflammatory activities of whole-plant extracts. Specific oleandrin concentrations in standardized extracts are not uniformly quantified in published sources, and no dietary reference intake or tolerable upper intake level has been established by any regulatory authority.

Preparation & Dosage

- **Aqueous Extract (Anvirzel)**: Investigational injectable formulation derived from N. oleander leaves; used in Phase I/II oncology trials; no approved therapeutic dose established for general use.
- **Supercritical CO2 Extract (PBI-05204)**: Concentrated lipophilic extract enriched in oleandrin; explored in pancreatic and other solid tumor trials at an investigational suggested dose of approximately 0.2255 mg/kg/day.
- **Hydroalcoholic Leaf Extract**: Traditional and laboratory preparation method; standardization to oleandrin content not uniformly established across commercial or research sources.
- **Isolated Oleandrin**: Pure compound used in mechanistic research; no safe supplemental dose defined for human use due to narrow therapeutic index and cardiotoxicity risk.
- **Cold-Water Extract (Breastin)**: Traditional cold-water preparation containing oleandrin alongside rutin, quercetin, and chlorogenic acid; historical use in folk medicine, not validated in controlled trials.
- **Important Note**: No established safe supplemental dose exists for general population use; all dosing references derive from supervised clinical trial protocols and must not be self-administered.

Synergy & Pairings

No clinically validated synergistic combinations involving oleandrin have been established in human trials; however, preclinical data suggest that oleandrin's mTOR inhibition may complement conventional chemotherapeutic agents targeting overlapping PI3K/Akt pathways, such as rapamycin analogs or EGFR inhibitors, though additive toxicity risks have not been systematically characterized. The co-presence of quercetin and rutin in whole N. oleander extracts (e.g., breastin) may contribute complementary antioxidant and anti-inflammatory activity that modulates the tumor microenvironment through distinct mechanisms from oleandrin's glycoside effects. Any stack pairing involving oleandrin remains entirely experimental and should not be pursued outside rigorously supervised clinical research given the compound's cardiotoxic profile.

Safety & Interactions

Oleandrin carries an extremely narrow therapeutic window and is classified as a potent cardiac glycoside toxin; ingestion of N. oleander plant material or concentrated oleandrin extracts has caused fatal cardiac arrhythmias, bradycardia, atrioventricular block, and ventricular fibrillation in humans and animals through sustained Na+/K+-ATPase inhibition, elevating intracellular calcium to lethal levels. Concurrent use with other cardiac glycosides (e.g., digoxin), antiarrhythmic agents, calcium channel blockers, or potassium-altering diuretics would be expected to produce dangerous additive cardiotoxicity, though formal drug interaction pharmacokinetic studies in humans are absent from the published literature. Oleandrin is absolutely contraindicated in individuals with pre-existing cardiac arrhythmias, heart block, hypokalemia, or hypomagnesemia, and is not recommended during pregnancy or lactation due to lack of safety data and known cytotoxic potential. No maximum safe dose has been established for non-clinical populations; oleandrin is not recommended as a nutritional supplement under any circumstances, and any investigational use must occur exclusively under medical supervision within a formal clinical trial framework.