Abstract
Vitex rotundifolia is a medicinal plant rich in terpenoids and flavonoids, whereas the liverwort Ptychanthus striatus represents an underexplored bryophyte source of specialized metabolites. In this study, a bioassay-guided phytochemical investigation of Vietnamese V. rotundifolia leaves and P. striatus was conducted to identify natural inhibitors of SARS-CoV-2 main protease (Mpro). The crude methanol extracts and selected fractions showed inhibitory activity against SARS-CoV-2 Mpro, thereby guiding subsequent chromatographic separation. Thirteen compounds, including diterpenoids, lupane-type triterpenoids, and flavonoids, were isolated from V. rotundifolia, while ten terpenoid, phenolic, bibenzyl, and bisbibenzyl-type metabolites were obtained from P. striatus. Most isolated compounds are reported from these species for the first time, and compound P8 from P. striatus is described as a new natural product. All isolated compounds were evaluated for their inhibitory activity against SARS-CoV-2 Mpro. Among them, chrysoplenol D was the most potent inhibitor, with an IC50 value of 0.08 ± 0.01 µM, followed by selected phenolic/bibenzyl-type metabolites from P. striatus and other flavonoid derivatives from V. rotundifolia. Most diterpenoids showed weak or negligible inhibition. Molecular docking studies supported the experimental results by showing that representative active compounds could bind within the catalytic pocket of SARS-CoV-2 Mpro and interact with key residues, including His41, Gly143, and Cys145. These findings expand the phytochemical knowledge of Vietnamese V. rotundifolia and P. striatus and highlight chrysoplenol D and related flavonoid or bibenzyl-type natural products as promising scaffolds for further development of SARS-CoV-2 Mpro inhibitors.
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Claims 9
Claim · model-written summary
Thirteen compounds were isolated from Vitex rotundifolia.
- Taxon
- V. rotundifolia
Vitex rotundifoliae0 - Outcome
- compounds, including diterpenoids, lupane-type triterpenoids, and flavonoidse0
- Value
- Thirteen compoundse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Thirteen compounds, including diterpenoids, lupane-type triterpenoids, and flavonoids, were isolated from V. rotundifolia,”
Claim · model-written summary
Ten metabolites were obtained from Ptychanthus striatus.
- Taxon
- P. striatusPtychanthus striatuse0
- Outcome
- terpenoid, phenolic, bibenzyl, and bisbibenzyl-type metabolitese0
- Value
- ten terpenoide0
Verbatim
e0“ten terpenoid, phenolic, bibenzyl, and bisbibenzyl-type metabolites were obtained from P. striatus.”
Claim · model-written summary
Most isolated compounds were reported from these species for the first time.
- Taxon
- Vitex rotundifoliaVitex rotundifoliat0
- Outcome
- isolated compoundse0
- Qualifier
- for the first timee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Most isolated compounds are reported from these species for the first time,”
t0“Vitex rotundifolia”
Claim · model-written summary
Compound P8 from P. striatus was described as a new natural product.
- Taxon
- P. striatusPtychanthus striatuse0
- Outcome
- compound P8e0
- Qualifier
- new natural producte0
Verbatim
e0“compound P8 from P. striatus is described as a new natural product.”
Claim · model-written summary
Chrysoplenol D was the most potent SARS-CoV-2 Mpro inhibitor, with an IC50 of 0.08 ± 0.01 µM.
- Taxon
- Vitex rotundifoliaVitex rotundifoliat0
- Outcome
- most potent inhibitore0
- Value
- 0.08 ± 0.01 µMe0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“chrysoplenol D was the most potent inhibitor, with an IC50 value of 0.08 ± 0.01 µM,”
t0“Vitex rotundifolia”
Claim · model-written summary
Selected phenolic and bibenzyl metabolites from P. striatus followed chrysoplenol D in inhibitory potency.
- Taxon
- P. striatusPtychanthus striatuse0
- Outcome
- phenolic/bibenzyl-type metabolitese0
- Direction
- followed bye0
Verbatim
e0“followed by selected phenolic/bibenzyl-type metabolites from P. striatus”
Claim · model-written summary
Other flavonoid derivatives from V. rotundifolia followed chrysoplenol D in inhibitory potency.
- Taxon
- V. rotundifoliaVitex rotundifoliae0
- Outcome
- flavonoid derivativese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“other flavonoid derivatives from V. rotundifolia.”
Claim · model-written summary
Most diterpenoids had weak or negligible protease inhibition.
- Taxon
- Vitex rotundifoliaVitex rotundifoliat0
- Outcome
- diterpenoids showed weak or negligible inhibitione0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Most diterpenoids showed weak or negligible inhibition.”
t0“Vitex rotundifolia”
Claim · model-written summary
Docking showed representative active compounds binding in the Mpro catalytic pocket and interacting with His41, Gly143, and Cys145.
- Taxon
- Vitex rotundifoliaVitex rotundifoliat0
- Outcome
- bind within the catalytic pocket of SARS-CoV-2 Mproe0
- Qualifier
- His41, Gly143, and Cys145e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“representative active compounds could bind within the catalytic pocket of SARS-CoV-2 Mpro and interact with key residues, including His41, Gly143, and Cys145.”
t0“Vitex rotundifolia”