Lycorine (Amaryllidaceae Alkaloid · Antiviral · Antiproliferative · Daffodil Emetic)

Compound	Lycorine
Chemical class	Alkaloid — Amaryllidaceae (Phenanthridine; isocarbostyril-type Amaryllidaceae alkaloid)
CAS	476-28-8
Primary source	Lycoris radiata (red spider lily bulbs), Narcissus spp. (daffodil), Galanthus spp. (snowdrop)
Key applications	Antiviral; antiproliferative; emetic; AChE inhibition (weak); galantamine biosynthetic precursor; availability on request
Claim strength	Moderate
Typical form	Lycoris or Narcissus bulb extract; lycorine isolate (research grade)
Buy from Herbuno	Request availability and bulk pricing →

Name origin: From Lycoris (the red spider lily genus, named after a Roman actress beloved by Mark Antony). Lycorine is one of the most abundant and widely distributed Amaryllidaceae alkaloids — occurring in virtually all members of the Amaryllidaceae family (daffodils, snowdrops, spider lilies, Narcissus, Hippeastrum). It is the first Amaryllidaceae alkaloid to accumulate in biosynthesis and the direct biosynthetic precursor for many downstream Amaryllidaceae alkaloids including galantamine and narciclasine. Traditional use: Amaryllidaceae bulbs have traditional use in various cultures — Lycoris species are used in Traditional Chinese Medicine (Shi Suan, meaning “stone garlic”) for anti-inflammatory, antiviral, and anticancer applications. The emetic properties of daffodil/narcissus bulbs (from lycorine) have caused numerous poisoning incidents when bulbs are mistaken for onions — a recurrent food safety issue. Research trajectory: Lycorine attracted significant research attention for: (1) antiviral activity against SARS-CoV, SARS-CoV-2, influenza, Zika, and other viruses via protein synthesis inhibition; (2) antiproliferative activity in cancer cell lines via ROS generation and apoptosis induction; (3) weak AChE inhibitory activity relevant to Alzheimer’s research. Lycorine is considered one of the most pharmacologically versatile Amaryllidaceae alkaloids. Commercial source: Not currently in the Herbuno catalogue. Contact Herbuno for availability assessment.

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Evidence for Lycorine Applications

Antiviral — broad spectrum: Lycorine inhibits replication of SARS-CoV, SARS-CoV-2, MERS-CoV, influenza A/B, Zika, dengue, Chikungunya, and poliovirus at low micromolar concentrations. Mechanisms include: inhibition of 60S ribosomal subunit translocation (reducing viral protein synthesis), interference with viral entry, and induction of antiviral interferon-stimulated genes. The SARS-CoV-2 antiviral activity (EC50 ~1 μM) positioned lycorine as a potential COVID-19 candidate during the pandemic. Claim strength: Moderate (in vitro; animal studies; no completed human clinical trials for antiviral).

Antiproliferative — multiple cancer cell lines: Lycorine induces apoptosis and cell cycle arrest in leukaemia (HL-60), multiple myeloma, breast, colon, prostate, and glioma cell lines at 1–10 μM concentrations. The mechanism involves ROS generation, mitochondrial membrane potential disruption, and caspase cascade activation. Some selectivity for cancer cells over normal cells is reported. Claim strength: Moderate (convergent preclinical; no human oncology trials).

Emetic activity and toxicological context: Lycorine is the primary emetic principle responsible for toxicity from accidental ingestion of daffodil and narcissus bulbs. At sub-emetic doses, lycorine has demonstrated antiviral and antiproliferative activities in research models, but the dose separation between emetic and therapeutic effects is a formulation challenge. Safety reference: important for formulators considering Amaryllidaceae extracts.

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Frequently Asked Questions — Lycorine

Is lycorine the compound that makes daffodil bulbs poisonous?
Lycorine is the primary emetic and toxic alkaloid in daffodil (Narcissus) and other Amaryllidaceae bulbs. Ingestion of daffodil bulbs (most commonly when confused with onions or shallots) causes rapid-onset nausea, vomiting, salivation, diarrhoea, and lethargy — mediated by lycorine’s direct irritant and emetic effects. Serious toxicity is rare because the emetic effect limits further ingestion, but children and livestock can be affected. Other toxic Amaryllidaceae alkaloids (narciclasine, haemanthamine) also contribute to toxicity of concentrated plant materials.

Why was lycorine considered a COVID-19 candidate?
In early COVID-19 drug screening (2020), lycorine was identified as having in vitro SARS-CoV-2 inhibitory activity at low micromolar concentrations (EC50 ~1.0 μM, SI >5). The mechanism (ribosomal translocation inhibition reducing viral protein synthesis) is distinct from nucleoside analogues (remdesivir) or protease inhibitors (nirmatrelvir), making it a mechanistically interesting candidate. The challenge for clinical development: lycorine’s emetic activity at higher doses would limit dose escalation, and its pharmacokinetic profile requires optimisation. It was not advanced to clinical trials for COVID-19.

How does lycorine relate to galantamine?
Lycorine and galantamine are both Amaryllidaceae alkaloids from the same plant family — notably from Galanthus (snowdrop) species. Biosynthetically, lycorine (or its precursors) is an intermediate on the pathway to several Amaryllidaceae alkaloids. The structural relationship is not direct — galantamine has a different ring system from lycorine — but they share the Amaryllidaceae alkaloid biosynthetic pathway. Both have AChE inhibitory activity (galantamine is far more potent), and both occur in snowdrop bulbs alongside narciclasine and other Amaryllidaceae alkaloids.

Can lycorine be used topically without emetic risk?
The emetic activity of lycorine is from GI mucosal contact and systemic absorption causing CTZ stimulation — not a skin-level mechanism. Topical application of lycorine-containing botanical extracts on intact skin (not near mucous membranes) should not produce emetic effects at concentrations used in cosmetic or topical formulations. The antiproliferative and anti-inflammatory activity of lycorine in topical contexts is scientifically interesting for skin formulations where its emetic GI limitation does not apply.

Related compounds: Galantamine, Narciclasine, Emetine, Noscapine

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Claim-strength scale – High = multiple human RCTs; Moderate = limited trials or strong preclinical convergence; Emerging = early-stage lab or animal data.

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