Paper · 2026 · Frontiers in Pharmacology

Historical texts as a potential resource for plant-based antiviral agents against SARS-CoV-2: the example of the Receptarium of Burkhard III von Hallwyl from 16th-century Switzerland

Nina Vahekeni; Jonas Stehlin; Corinna Urmann; et al.

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claims
8
verbatim quotes
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citations
1
research areas
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Open access · cc-by

Abstract

Background In search for effective prophylactic and possibly curative therapeutics against SARS-CoV-2, an historical-ethnopharmacological approach was used to select plants described in the Receptarium of Burkhard III von Hallwyl (RBH), a recipe text from 16th century Switzerland. Ten plant species were selected from the pre-established RBH database based on specific historical uses presumably linked with the treatment of viral infections. Methods From each plant aqueous and hydroethanolic extracts were produced. CellTiter-Glo® Luminescent Cell Viability Assay was used to assess antiviral activity against SARS-CoV-2 and the effect on cell viability of the extracts. Results Of the ten plants tested, four displayed an antiviral activity ≥ 50% at 16.7 μg/ml with acceptable cell viability (> 75%): Artemisia vulgaris L. (aerial parts), Geranium robertianum L. (arial parts), Sambucus nigra L. (leaves) and Viola odorata L. (leaves). The crude extracts were partitioned in aqueous and organic pre-fractions and further analyzed. The ethyl acetate pre-fractions of G. robertianum, S. nigra , and V. odorata expressed significant antiviral activity of nearly 100% at 5.6 μg/ml (P < 0.05). The most potent inhibitory activity was observed for the ethyl acetate pre-fraction of the leaves of Viola odorata with 87% at 1.9 μg/ml (P < 0.0001). Alongside bioactivity testing, phytochemical fingerprints were made, with the aim to provide a preliminary characterization of the active crude extracts. An overview of published phytochemical and antiviral data on the four active plants reveals a fragmentary picture, especially when considering the plant parts investigated. Despite of the promising antiviral effects observed in our study, further in-depth pharmacological and phytochemical investigations are required to comprehensively evaluate the potential of our candidates. Conclusions Our study suggests that an ethnopharmacological approach based on historical records of plant use in combination with a rational selection and testing procedure allows to identify interesting candidates, even among medicinal plants no longer in use. The process of selecting plants from RBH also illustrates the challenges associated with the study of historical texts, particularly the interpretation of the medicinal uses and the assessment of the botanical identities of historical plant names.

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Claims 8

Observationobservedoriginal resultpositivemeasured

Claim · model-written summary

Artemisia vulgaris aerial parts extract showed antiviral activity of at least 50% at 16.7 μg/ml.

Taxon
Artemisia vulgarisArtemisia vulgarise1
Organ / stage
aerial partse1
Outcome
antiviral activitye1
Value
≥ 50%e1
Qualifier
at 16.7 μg/mle1

Organisms pictured · Representative pictures of the matched species, not figures from the paper.

Artemisia vulgaris
Artemisia vulgaris · TaxonNessun autore leggibile automaticamente. Rita~commonswiki presunto (secondo quanto affermano i diritti d'autore). · CC BY-SA 3.0 · Wikimedia Commons ↗

Verbatim

e1

“Of the ten plants tested, four displayed an antiviral activity ≥ 50% at 16.7 μg/ml with acceptable cell viability (> 75%): Artemisia vulgaris L. (aerial parts), Geranium robertianum L. (arial parts), Sambucus nigra L. (leaves) and Viola odorata L. (leaves)”

✓ located verbatim in the source · abstract, characters 682–938 · show in text ↑
Observationobservedoriginal resultpositivemeasured

Claim · model-written summary

Geranium robertianum aerial parts extract showed antiviral activity of at least 50% at 16.7 μg/ml.

Taxon
Geranium robertianumGeranium robertianume1
Organ / stage
arial partse1
Outcome
antiviral activitye1
Value
≥ 50%e1
Qualifier
at 16.7 μg/mle1

Organisms pictured · Representative pictures of the matched species, not figures from the paper.

Geranium robertianum
Geranium robertianum · TaxonDidier Descouens · CC BY-SA 4.0 · Wikimedia Commons ↗

Verbatim

e1

“Of the ten plants tested, four displayed an antiviral activity ≥ 50% at 16.7 μg/ml with acceptable cell viability (> 75%): Artemisia vulgaris L. (aerial parts), Geranium robertianum L. (arial parts), Sambucus nigra L. (leaves) and Viola odorata L. (leaves)”

✓ located verbatim in the source · abstract, characters 682–938 · show in text ↑
Observationobservedoriginal resultpositivemeasured

Claim · model-written summary

Sambucus nigra leaf extract showed antiviral activity of at least 50% at 16.7 μg/ml.

Taxon
Sambucus nigraSambucus nigrae1
Organ / stage
leavese1
Outcome
antiviral activitye1
Value
≥ 50%e1
Qualifier
at 16.7 μg/mle1

Organisms pictured · Representative pictures of the matched species, not figures from the paper.

Sambucus nigra
Sambucus nigra · TaxonW. Bulach · CC BY-SA 4.0 · Wikimedia Commons ↗

Verbatim

e1

“Of the ten plants tested, four displayed an antiviral activity ≥ 50% at 16.7 μg/ml with acceptable cell viability (> 75%): Artemisia vulgaris L. (aerial parts), Geranium robertianum L. (arial parts), Sambucus nigra L. (leaves) and Viola odorata L. (leaves)”

✓ located verbatim in the source · abstract, characters 682–938 · show in text ↑
Observationobservedoriginal resultpositivemeasured

Claim · model-written summary

Viola odorata leaf extract showed antiviral activity of at least 50% at 16.7 μg/ml.

Taxon
Viola odorataViola odoratae1
Organ / stage
leavese1
Outcome
antiviral activitye1
Value
≥ 50%e1
Qualifier
at 16.7 μg/mle1

Organisms pictured · Representative pictures of the matched species, not figures from the paper.

Viola odorata
Viola odorata · TaxonAnRo0002 · CC0 · Wikimedia Commons ↗

Verbatim

e1

“Of the ten plants tested, four displayed an antiviral activity ≥ 50% at 16.7 μg/ml with acceptable cell viability (> 75%): Artemisia vulgaris L. (aerial parts), Geranium robertianum L. (arial parts), Sambucus nigra L. (leaves) and Viola odorata L. (leaves)”

✓ located verbatim in the source · abstract, characters 682–938 · show in text ↑
Observationobservedoriginal resultpositivesignificant (as stated)measured

Claim · model-written summary

The ethyl acetate pre-fraction of G. robertianum showed nearly 100% antiviral activity at 5.6 μg/ml, significant at P < 0.05.

Taxon
G. robertianumGeranium robertianume2
Treatment
ethyl acetate pre-fractionse2
Outcome
antiviral activitye2
Value
nearly 100%e2
Qualifier
at 5.6 μg/mle2

Organisms pictured · Representative pictures of the matched species, not figures from the paper.

Geranium robertianum
Geranium robertianum · TaxonDidier Descouens · CC BY-SA 4.0 · Wikimedia Commons ↗

Verbatim

e2

“The ethyl acetate pre-fractions of G. robertianum, S. nigra , and V. odorata expressed significant antiviral activity of nearly 100% at 5.6 μg/ml (P < 0.05)”

✓ located verbatim in the source · abstract, characters 1035–1191 · show in text ↑
Observationobservedoriginal resultpositivesignificant (as stated)measured

Claim · model-written summary

The ethyl acetate pre-fraction of S. nigra showed nearly 100% antiviral activity at 5.6 μg/ml, significant at P < 0.05.

Taxon
S. nigraSambucus nigrae2
Treatment
ethyl acetate pre-fractionse2
Outcome
antiviral activitye2
Value
nearly 100%e2
Qualifier
at 5.6 μg/mle2

Organisms pictured · Representative pictures of the matched species, not figures from the paper.

Sambucus nigra
Sambucus nigra · TaxonW. Bulach · CC BY-SA 4.0 · Wikimedia Commons ↗

Verbatim

e2

“The ethyl acetate pre-fractions of G. robertianum, S. nigra , and V. odorata expressed significant antiviral activity of nearly 100% at 5.6 μg/ml (P < 0.05)”

✓ located verbatim in the source · abstract, characters 1035–1191 · show in text ↑
Observationobservedoriginal resultpositivesignificant (as stated)measured

Claim · model-written summary

The ethyl acetate pre-fraction of V. odorata showed nearly 100% antiviral activity at 5.6 μg/ml, significant at P < 0.05.

Taxon
V. odorataViola odoratae2
Treatment
ethyl acetate pre-fractionse2
Outcome
antiviral activitye2
Value
nearly 100%e2
Qualifier
at 5.6 μg/mle2

Organisms pictured · Representative pictures of the matched species, not figures from the paper.

Viola odorata
Viola odorata · TaxonAnRo0002 · CC0 · Wikimedia Commons ↗

Verbatim

e2

“The ethyl acetate pre-fractions of G. robertianum, S. nigra , and V. odorata expressed significant antiviral activity of nearly 100% at 5.6 μg/ml (P < 0.05)”

✓ located verbatim in the source · abstract, characters 1035–1191 · show in text ↑
Observationobservedoriginal resultpositivesignificant (as stated)measured

Claim · model-written summary

The ethyl acetate pre-fraction of Viola odorata leaves had the most potent inhibitory activity, 87% at 1.9 μg/ml (P < 0.0001).

Taxon
Viola odorataViola odoratae3
Organ / stage
leavese3
Treatment
ethyl acetate pre-fractione3
Outcome
inhibitory activitye3
Value
87%e3
Qualifier
1.9 μg/mle3

Organisms pictured · Representative pictures of the matched species, not figures from the paper.

Viola odorata
Viola odorata · TaxonAnRo0002 · CC0 · Wikimedia Commons ↗

Verbatim

e3

“The most potent inhibitory activity was observed for the ethyl acetate pre-fraction of the leaves of Viola odorata with 87% at 1.9 μg/ml (P < 0.0001)”

✓ located verbatim in the source · abstract, characters 1193–1342 · show in text ↑