A broad-spectrum antiviral from a bean
From bean to nasal spray
Start with lablab beans
Hyacinth beans (Lablab purpureus) are unusually rich in FRIL — around 2.5% of seed weight — and are already widely cultivated across Africa and Asia.
Capture on mannose beads
FRIL is mannose/glucose-specific, so it can be pulled straight out of a crude bean extract on a mannose-affinity resin and released with free sugar.
Formulate for the nose
An intranasal spray puts FRIL where respiratory viruses are most likely to enter the body.
Measure potency and safety
Planned work includes shelf life testing and studies on nasal epithelial tolerability.
How FRIL stops a virus
Influenza hemagglutinin and coronavirus spike are both heavily glycosylated. FRIL is a homotetramer with four carbohydrate-binding sites — two facing each end — so one molecule can hold two virus particles at once. Drag to rotate; the steps below jump through the sequence.
A glycan shield, and a way in. Influenza hemagglutinin and coronavirus spike are heavily coated in N-glycans (green). The glycans shield the virus from antibodies — but they are also hard to mutate away, which makes them a target.
virion N-glycan FRIL tetramer binding site
What has been published
| Study | Journal | System | What was shown |
|---|---|---|---|
| Liu et al. 2020 | Cell Reports | Influenza (11 strains), SARS-CoV-2 | FRIL neutralized 11 human and avian influenza strains at low nanomolar concentrations and neutralized SARS-CoV-2 in cell culture. Intranasal FRIL protected mice against a lethal H1N1 challenge. Electron microscopy and light scattering showed FRIL aggregating virions. |
| Daniell et al. 2022 | Biomaterials | SARS-CoV-2 (Delta, Omicron, OC43), H1N1, H3N2 | FRIL delivered in a chewing gum reduced virus in clinical nasopharyngeal samples; 50% plaque reduction at 50–100 ng of purified FRIL. Electron micrographs showed densely packed clumps of influenza particles and FRIL. |
| Daniell et al. 2025 | Molecular Therapy | HSV-1, HSV-2, H1N1, H3N2 | Bean gum extracts trapped 75–94% of HSV-1/HSV-2 through self-aggregation. FRIL remained stable 683 days in bean powder and 790 days in gum, and functional at 794 days, stored at ambient temperature. |
| Daniell et al. 2026 | Scientific Reports | Oral HPV (patient samples) | In an ex vivo study of head-and-neck cancer patients, bean-lectin gum aggregated 93% of HPV in saliva and 80% in oral-rinse samples. |
| Liu et al. 2026 | Nature Communications | Structure | Structure-guided engineering identified loop B residues as the determinant of FRIL's preference for complex-type over high-mannose N-glycans — the trait that separates it from lectins like concanavalin A. |
Help us with this work
Feedback, criticism, and suggestions are all welcome.