Nikhil Prasad Fact checked by:Thailand Medical News Team Sep 29, 2025 14 hours, 47 minutes ago
Medical News: In the search for better ways to fight epidemic viruses like COVID-19, dengue, and Zika, scientists are now looking toward the power of nature. A major scientific review has examined dozens of phytochemicals, which are natural compounds found in plants, and highlighted how they may help in preventing and controlling viral infections. Unlike synthetic drugs that can be costly, toxic, and prone to resistance, these natural plant compounds are safe, affordable, and already part of the diets and herbal traditions of millions of people around the world.
Natural Plant Compounds Could Change the Fight Against Viruses
The research was conducted by scientists from top medical and research institutions in Mexico: the Hospital Infantil de México Federico Gómez, Universidad Nacional Autónoma de México, Instituto Mexicano del Seguro Social (IMSS), Instituto de Seguridad y Servicios Sociales para los Trabajadores al Servicio del Estado (ISSSTE), Instituto Nacional de Medicina Genómica, and Instituto Politécnico Nacional. According to this
Medical News report, these researchers found strong evidence that certain phytochemicals can stop viruses from entering cells, block viral proteins that allow replication, and even reduce mosquito transmission in the case of dengue and Zika.
The Growing Challenge of Epidemic Viruses
Viruses such as SARS-CoV-2, dengue, and Zika continue to cause devastating illness worldwide. Modern antiviral drugs are limited, often expensive, and sometimes lose effectiveness as viruses mutate and develop resistance. Vaccines remain a cornerstone of prevention but are not always available, effective for all populations, or long-lasting. This reality has sparked new interest in exploring the role of phytochemicals as supportive or complementary tools that could be used alongside vaccines and antivirals.
Phytochemicals are already known for their antioxidant, anti-inflammatory, and antimicrobial properties, but the current review reveals how many of them also act as powerful antivirals. By disrupting different stages of viral life cycles, they can reduce the severity of infections and, in some cases, even slow down transmission at the population level.
Key Phytochemicals and Their Origins
The review listed dozens of phytochemicals with antiviral potential, each derived from specific plants:
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Quercetin – A flavonoid found in onions, apples, grapes, berries, tea, and wine; shown to block SARS-CoV-2 entry, reduce inflammation, and act as an inhibitor of viral proteases.
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Curcumin – A yellow polyphenol from turmeric (Curcuma longa); disrupts replication of Zika, chikungunya, and influenza viruses while also regulating immune responses.
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Carica papaya leaf extract – Rich in flavonoids and other bioactives; raises platelet counts in dengue patients, reduces viral replication, and may also act against Zika.
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Baicalin – Derived from Scutellaria baicalensis and Scutellaria lateriflora; prevents entry of dengue and Zika viruses.
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Castanospermine – An alkaloid from Castanospermine australe; suppresses dengue infectivity across all serotypes.
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Celastrol – A triterpene from Tripterygium wilfordii (Thunder God Vine); enhances interferon response to fight dengue.
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1,8-Cineole – A monoterpene from eucalyptus; reduces lung inflammation and immune overreaction in influenza.
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Echinocystic acid and Oleanolic acid – From Xanthoceras sorbifolia; disrupt viral proteins in HIV, influenza, and hepatitis C.
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Epigallocatechin gallate (EGCG) – From green tea (Camellia sinensis); blocks influenza binding and inhibits Zika entry.
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Ginkgolic acid – From Ginkgo biloba; prevents replication of Zika and chikungunya viruses.
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Glycyrrhizin – A triterpene from licorice root (Glycyrrhiza glabra); blocks SARS-CoV-2 by targeting its main protease.
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Honokiol – A lignan from magnolia bark; interferes with dengue replication and viral gene expression.
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Oxyresveratrol – From Artocarpus lakoocha; inhibits herpes viruses HSV-1 and HSV-2, especially in combination with acyclovir.
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Sennosides A and B – Glycosides from rhubarb (Rheum palmatum); disrupt HIV assembly.
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Silvestrol – From Aglaia foveolata; blocks Ebola virus infection.
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Tangeretin and Nobiletin – Citrus peel flavones; interfere with RSV replication.
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Kaempferol – Found in many fruits and vegetables; binds strongly to viral proteins in Zika and dengue.
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Caffeic acid, Chlorogenic acid, Protocatechuic acid, p-Coumaric acid – Phenolic acids in coffee, fruits, and herbs; all show antiviral binding activity in laboratory models.
How They Work
These compounds act at several levels of viral infection. Some, like quercetin and baicalin, block viral entry into cells by binding to envelope proteins. Others, like glycyrrhizin and Celastrol, interfere with proteases and enzymes critical for replication. Papaya leaf extract has a unique effect in dengue by not only helping platelet recovery but also by acting on the NS2B/NS3 protease and RNA polymerase of the virus. Curcumin supports the immune system by boosting interferon pathways and reducing overactive inflammation, making it particularly useful against respiratory viruses like SARS-CoV-2.
Another fascinating aspect is vector control. Compounds from papaya leaves also have larvicidal properties against Aedes mosquitoes, suggesting that phytochemicals could help reduce transmission of dengue and Zika by targeting the insect carriers, not just the viruses themselves.
Clinical Evidence
Clinical and experimental evidence strengthens these findings. In dengue patients, papaya leaf extract has consistently been linked to improved platelet counts and faster recovery. In COVID-19 patients, quercetin used as a supplement improved outcomes, shortened recovery time, reduced inflammation, and enhanced the effect of standard treatments. In some studies, quercetin combined with curcumin and vitamin D3 accelerated symptom resolution in outpatients. Curcumin alone has also shown promise in lowering viral replication and calming damaging immune responses.
Future Potential
The integration of phytochemicals into modern healthcare could mark a turning point in how we fight epidemics. Their presence in common foods means they could be promoted through dietary guidance as well as supplements. Their natural abundance and safety profile make them accessible to low-income populations that cannot easily afford advanced drugs. Most importantly, their multitargeted antiviral mechanisms may reduce the chances of resistance compared to single-target synthetic drugs.
Conclusion
Phytochemicals offer a powerful and sustainable path forward in the battle against viral epidemics. Unlike conventional drugs, they are already present in daily diets and traditional medicines, making them low-cost and accessible. By blocking viral entry, inhibiting replication, boosting immune function, and even reducing mosquito transmission, compounds such as quercetin, curcumin, papaya leaf extracts, Celastrol, and glycyrrhizin provide a wide range of antiviral defenses.
Future clinical trials are essential, but the evidence suggests that diets rich in these natural compounds could reduce both the severity and spread of diseases like COVID-19, dengue, and Zika. In a world where new pandemics are inevitable, phytochemicals may be one of the most valuable tools available. Their promise lies not only in treatment but also in prevention, offering a low-cost and eco-friendly solution that can benefit populations globally. Harnessing their potential could reshape epidemic preparedness and create a healthier, more resilient future for all.
The study findings were published in the peer reviewed journal: Natural Product Communications.
https://journals.sagepub.com/doi/full/10.1177/1934578X251333232
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https://www.thailandmedical.news/news/phytochemical-found-in-licorice-shows-strong-potential-against-flu-viruses
https://www.thailandmedical.news/news/philippine-medicinal-plants-show-strong-potential-against-covid-19
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