Antiviral effect of cimicifugin from Cimicifuga foetida against human respiratory syncytial virus

Cimicifugin, a broad-spectrum inhibitor of Theileria annulata and Plasmodium falciparum CDK7

Cyclin-dependent kinase 7 is an attractive therapeutic target for the treatment of cancers, and a previous report suggested that Plasmodium falciparum CDK7 is a potential drug target for developing new anti-malarial drugs. In this study, we aimed to characterize and evaluate the drug target potential of Theileria annulata CDK7. Theileria annulata is responsible for tropical theileriosis, which induces a phenotype similar to cancerous cells like immortalization, hyperproliferation, and dissemination. Virtual screening of the MyriaScreen II library predicted 14 compounds with high binding energies to the ATP-binding pocket of TaCDK7. Three compounds (cimicifugin, ST092793, and ST026925) of these 14 compounds were non-cytotoxic to the uninfected bovine cells (BoMac cells). Cimicifugin treatment led to the activation of the extrinsic apoptosis pathway and induced autophagy in T. annulata-infected cells. Furthermore, cimicifugin also inhibited the growth of P. falciparum, indicating that it has both anti-theilerial and anti-malarial activities and that TaCDK7 and PfCDK7 are promising drug targets.

Traditional uses, phytochemistry, pharmacology, quality control and clinical studies of Cimicifugae Rhizoma: a comprehensive review

Cimicifugae Rhizoma, generally known as "Sheng Ma" in China, has great medicinal and dietary values. Cimicifugae Rhizoma is the dried rhizome of Cimicifuga foetida L., Cimicifuga dahurica (Turcz.) Maxim. and Cimicifuga heracleifolia Kom., which has been used to treat wind-heat headache, tooth pain, aphtha, sore throat, prolapse of anus and uterine prolapse in traditional Chinese medicine. This review systematically presents the traditional uses, phytochemistry, pharmacology, clinical studies, quality control and toxicity of Cimicifugae Rhizoma in order to propose scientific evidence for its rational utilization and product development. Herein, 348 compounds isolated or identified from the herb are summarized in this review, mainly including triterpenoid saponins, phenylpropanoids, chromones, alkaloids, terpenoids and flavonoids. The crude extracts and its constituents had various pharmacological properties such as anti-inflammatory, antitumor, antiviral, antioxidant, neuroprotective, anti-osteoporosis and relieving menopausal symptoms. The recent research progress of Cimicifugae Rhizoma in ethnopharmacology, phytochemistry and pharmacological effects demonstrates the effectiveness of its utilization and supplies valuable guidance for further research. This review will provide a basis for the future development and utilization of Cimicifugae Rhizoma.

Phytochemistry and ethnopharmacological studies of genus Cimicifuga: A systematic and comprehensive review

ETHNOPHARMACOLOGICAL USES

Black cohosh, also known as Cimicifuga sp., is one of the most widely used ethnomedicine for the treatment of major health issues in women. Some reports show that Cimicifuga sp. exhibit anti-cancer, anti-viral, anti-microbial, anti-pyretic, and anti-inflammatory properties.

PURPOSE OF THIS REVIEW

The objective of this comprehensive review is to furnish current and exhaustive knowledge pertaining to the pharmacological, phytochemical, and therapeutic properties of Cimicifuga sp.

MATERIALS AND METHODS

In this review, all the available information was collected on Cimicifugasp. via computerized search using Google Scholar, PubMed, Research Gate, Sci-Hub, supplementary resources (books, government reports, and Ph.D. theses).

RESULT

The phytochemical investigation on Cimicifuga sp. has shown phytoconstituents such as triterpenoid glycosides, phenylpropanoid, flavonoids, saponin, lignan, nitrogenous compounds, alkaloids, 4α-Methyl steroids and some other component like monoterpene lactones cimicifugolides A-C etc. Cimicifuga conveys a wide scope of research on in-vitro and in-vivo pharmacological potential, like anti-cancer, anti-microbial, anti-viral, anti-inflammatory, estrogenic, anti-oxidant, anti-neoplastic, anti-depressant, anti-Alzheimer, and anti-climacteric properties.

CONCLUSION

This article discusses the medicinal and traditional histories of various Cimicifuga species. Because quality control and safety assessments of Cimicifuga species are currently lacking, only a limited portion of the plant may be used as medication. The majority of current research focuses on triterpene glycosides. Although there are a variety of additional molecules that may have novel biological functions, systematic investigations of these compounds are lacking. The Cimicifuga plant has to go through a lot of studies before it can be completely used in clinics as a viable medicinal contender.

A Comprehensive Quality Evaluation of Cimicifugae Rhizoma Using UPLC-Q-Orbitrap-MS/MS Coupled with Multivariate Chemometric Methods

BACKGROUND

Cimicifugae Rhizoma, known in Chinese as Shengma, is a common medicinal material in traditional Chinese medicine (TCM), mainly used for treating wind-heat headaches, sore throat, uterine prolapse, and other diseases.

OBJECTIVES

An approach using a combination of ultra-performance liquid chromatography (UPLC), MS, and multivariate chemometric methods was designed to assess the quality of Cimicifugae Rhizoma.

METHODS

All materials were crushed into powder and the powdered sample was dissolved in 70% aqueous methanol for sonication. Chemometric methods, including hierarchical cluster analysis (HCA), principal component analysis (PCA), and orthogonal partial least-squares discriminant analysis (OPLS-DA), were adopted to classify and perform a comprehensive visualization study of Cimicifugae Rhizoma. The unsupervised recognition models of HCA and PCA obtained a preliminary classification and provided a basis for classification. In addition, we constructed a supervised OPLS-DA model and established a prediction set to further validate the explanatory power of the model for the variables and unknown samples.

RESULTS

Exploratory research found that the samples were divided into two groups, and the differences were related to appearance traits. The correct classification of the prediction set also demonstrated a strong predictive ability of the models for new samples. Subsequently, six chemical makers were characterized by UPLC-Q-Orbitrap-MS/MS, and the content of four components was determined. The results of the content determination revealed the distribution of representative chemical markers caffeic acid, ferulic acid, isoferulic acid, and cimifugin in two classes of samples.

CONCLUSIONS

This strategy can provide a reference for assessing the quality of Cimicifugae Rhizoma, which is significant for the clinical practice and QC of Cimicifugae Rhizoma.

HIGHLIGHTS

The HCA, PCA and OPLS-DA models visually classify Cimicifugae Rhizoma by appearance traits and obtain the chemical markers that influence the classification. The training and prediction sets were built to demonstrate the accuracy of the classification. Advanced UPLC-Q-Orbitrap-MS/MS technology provides powerful elucidation of critical chemical markers.

Overview of Viral Pneumonia Associated With Influenza Virus, Respiratory Syncytial Virus, and Coronavirus, and Therapeutics Based on Natural Products of Medicinal Plants

Viral pneumonia has been a serious threat to global health, especially now we have dramatic challenges such as the COVID-19 pandemic. Approximately six million cases of community-acquired pneumonia occur every year, and over 20% of which need hospital admission. Influenza virus, respiratory virus, and coronavirus are the noteworthy causative agents to be investigated based on recent clinical research. Currently, anaphylactic reaction and inflammation induced by antiviral immunity can be incriminated as causative factors for clinicopathological symptoms of viral pneumonia. In this article, we illustrate the structure and related infection mechanisms of these viruses and the current status of antiviral therapies. Owing to a set of antiviral regiments with unsatisfactory clinical effects resulting from side effects, genetic mutation, and growing incidence of resistance, much attention has been paid on medicinal plants as a natural source of antiviral agents. Previous research mainly referred to herbal medicines and plant extracts with curative effects on viral infection models of influenza virus, respiratory virus, and coronavirus. This review summarizes the results of antiviral activities of various medicinal plants and their isolated substances, exclusively focusing on natural products for the treatment of the three types of pathogens that elicit pneumonia. Furthermore, we have introduced several useful screening tools to develop antiviral lead compounds.

Medicinal plants: Treasure for antiviral drug discovery

The pandemic of viral diseases like novel coronavirus (2019-nCoV) prompted the scientific world to examine antiviral bioactive compounds rather than nucleic acid analogous, protease inhibitors, or other toxic synthetic molecules. The emerging viral infections significantly associated with 2019-nCoV have challenged humanity's survival. Further, there is a constant emergence of new resistant viral strains that demand novel antiviral agents with fewer side effects and cell toxicity. Despite significant progress made in immunization and regenerative medicine, numerous viruses still lack prophylactic vaccines and specific antiviral treatments that are so often influenced by the generation of viral escape mutants. Of importance, medicinal herbs offer a wide variety of therapeutic antiviral chemotypes that can inhibit viral replication by preventing viral adsorption, adhering to cell receptors, inhibiting virus penetration in the host cell, and competing for pathways of activation of intracellular signals. The present review will comprehensively summarize the promising antiviral activities of medicinal plants and their bioactive molecules. Furthermore, it will elucidate their mechanism of action and possible implications in the treatment/prevention of viral diseases even when their mechanism of action is not fully understood, which could serve as the base for the future development of novel or complementary antiviral treatments.

Yindan Jiedu Granules, a Traditional Chinese Medicinal Formulation, as a Potential Treatment for Coronavirus Disease 2019

Background:YindanJiedu Granules (YDJDG) have been newly prescribed as a Chinese herbal formula. This study aimed to compare the efficacy of YDJDG and lopinavir-ritonavir in the treatment of coronavirus disease 2019 (COVID-19).

Methods: Overall, 131 patients with COVID-19 were included in this study. In addition to standard care, 60 of these patients received YDJDG (YDJDG group) and 71 received lopinavir-ritonavir (lopinavir-ritonavir group). Propensity score matching (PSM) was used to match the characteristics of individuals in the two groups, while the Kaplan-Meier method was used to compare the proportion recovery observed.

Results: Cox analysis revealed that YDJDG and CD4 ≥ 660 cells/µL were independent predictive factors of proportion recovery. At baseline, disease types differed between the YDJDG and lopinavir-ritonavir treatment groups. Furthermore, no significant adverse effects or toxicities relevant to YDJDG were observed. The median recovery time was 21 days in the YDJDG group and 27 days in the lopinavir-ritonavir group. After PSM (1:1), 50 patient pairs, YDJDG vs. lopinavir-ritonavir, were analyzed. In the YDJDG group, the proportion of recovered patients was remarkably higher than that observed in the lopinavir-ritonavir group (p = 0.0013), especially for those presenting mild/moderate disease type and CD4 < 660 cells/µL. In the YDJDG group, the mean duration of fever and pulmonary exudative lesions was significantly shorter than that observed in the lopinavir-ritonavir group (p = 0.0180 and p = 0.0028, respectively).

Conclusion: YDJDG reveals the potential to hasten the recovery period in COVID-19 patients with mild/moderate disease type or CD4 < 660 cells/µL by shortening the mean duration of fever and pulmonary exudative lesions.

Plants-Derived Biomolecules as Potent Antiviral Phytomedicines: New Insights on Ethnobotanical Evidences against Coronaviruses

SARS-CoV-2 infection (COVID-19) is in focus over all known human diseases, because it is destroying the world economy and social life, with increased mortality rate each day. To date, there is no specific medicine or vaccine available against this pandemic disease. However, the presence of medicinal plants and their bioactive molecules with antiviral properties might also be a successful strategy in order to develop therapeutic agents against SARS-CoV-2 infection. Thus, this review will summarize the available literature and other information/data sources related to antiviral medicinal plants, with possible ethnobotanical evidence in correlation with coronaviruses. The identification of novel antiviral compounds is of critical significance, and medicinal plant based natural compounds are a good source for such discoveries. In depth search and analysis revealed several medicinal plants with excellent efficacy against SARS-CoV-1 and MERS-CoV, which are well-known to act on ACE-2 receptor, 3CLpro and other viral protein targets. In this review, we have consolidated the data of several medicinal plants and their natural bioactive metabolites, which have promising antiviral activities against coronaviruses with detailed modes of action/mechanism. It is concluded that this review will be useful for researchers worldwide and highly recommended for the development of naturally safe and effective therapeutic drugs/agents against SARS-CoV-2 infection, which might be used in therapeutic protocols alone or in combination with chemically synthetized drugs.

Unraveling the Molecular Mechanism of Traditional Chinese Medicine: Formulas Against Acute Airway Viral Infections as Examples

Herbal medicine, including traditional Chinese medicine (TCM), is widely used worldwide. Herbs and TCM formulas contain numerous active molecules. Basically, they are a kind of cocktail therapy. Herb-drug, herb-food, herb-herb, herb-microbiome, and herb-disease interactions are complex. There is potential for both benefit and harm, so only after understanding more of their mechanisms and clinical effects can herbal medicine and TCM be helpful to users. Many pharmacologic studies have been performed to unravel the molecular mechanisms; however, basic and clinical studies of good validity are still not enough to translate experimental results into clinical understanding and to provide tough evidence for better use of herbal medicines. There are still issues regarding the conflicting pharmacologic effects, pharmacokinetics, drug interactions, adverse and clinical effects of herbal medicine and TCM. Understanding study validation, pharmacologic effects, drug interactions, indications and clinical effects, adverse effects and limitations, can all help clinicians in providing adequate suggestions to patients. At present, it would be better to use herbs and TCM formulas according to their traditional indications matching the disease pathophysiology and their molecular mechanisms. To unravel the molecular mechanisms and understand the benefits and harms of herbal medicine and TCM, there is still much work to be done.

Antiviral Evaluation of Herbal Drugs

The viral infection and resistance to the existing antiviral drugs are alarming, which is a serious public health concern. Medicinal plants are valuable resources for treatment of viral infections and can be used for the management of infections like herpes simplex virus (HSV), human immunodeficiency virus (HIV), influenza, etc. The antiviral screening of plant extracts should be highly selective, specific, and sensitive for bioactivity guided isolation of the active compounds from the plant extracts. The antiviral screening system should be validated for accuracy, reproducibility, simplicity, and cost effectiveness. This chapter highlights on various aspects for screening and evaluation of antiviral natural components including factors affecting antiviral in vivo studies, host cells, organisms, and culture media followed by different virus-specific assays for antiviral screening of natural products.

In vitro antiviral, anti-inflammatory, and antioxidant activities of the ethanol extract of Mentha piperita L

The objective of this study is to investigate the antiviral, anti-inflammatory, and antioxidant effects of the ethanol extract of Mentha piperita L. leaves (MPE). M. piperita L. leaves were extracted by reflux with ethanol. Total phenolic acid and total flavonoid content were determined. The antiviral activity of MPE against the respiratory syncytial virus (RSV) and the anti-inflammatory activity were evaluated in vitro. The levels of key pre-inflammatory mediators and cytokines including nitric oxide (NO), tumor necrosis factor alpha (TNF-α), interleukin (IL)-6, and prostaglandin E2 (PGE2) were determined. The antioxidant activities were also evaluated using a colorimetry method. MPE contained high levels of phenolic acid and flavonoid, showed antiviral activity against RSV with a high selectivity index, and significantly decreased the production of NO, TNF-α, IL-6, and PGE2 in lipopolysaccharide-stimulated RAW 264.7 cells. Meanwhile, MPE showed potential free-radical scavenging activities. These results indicate that Mentha piperita L. might be a good source of medicinal plants.

Traditional uses, phytochemistry, pharmacology and toxicology of the genus Cimicifuga: A review

ETHNOPHARMACOLOGICAL RELEVANCE

Plants of the genus Cimicifuga have long been used as an ethnomedicine in China, Europe, and North America for its high medicinal value and health benefits. Their dried rhizomes are widely used for treating wind-heat headache, toothache, aphtha, sore throat, measles, spot poison, archoptosis, and uterine prolapse. In addition, it is used as a dietary supplement for preventing women menopausal symptoms and osteoporosis.

AIM OF THE REVIEW

This paper aims to provide up-to-date information on the genus Cimicifuga, including botanical characterization, medicinal resources, traditional medicinal uses, phytochemistry, quality control, pharmacological research as well as the toxicology. The possible structural-activity relationships and molecular mechanisms of the bioactive constituents are discussed in ways that contribute to the structural optimization and preclinical safety assessment for further drug design.

MATERIALS AND METHODS

The relevant information on Cimicifuga was collected from scientific databases (such as Google Scholar, PubMed, SciFinder Scholar, Science Direct, CNKI, Baidu Scholar, Web of Science, China Knowledge Resource Integrated Database), Chinese herbal classics, ethnobotanical books, PhD and MSc dissertations, Chinese Pharmacopoeia, published articles in peer-reviewed journals, local magazines, and unpublished materials. In addition, the Plant List (TPL, www.theplantlist.org) was also used to validate the scientific names and synonyms of this plant. The literature cited in this review dated from 1953 to 2017.

RESULTS

The majority of chemical constituents of this plant include triterpenoid glycosides, phenylpropanoids, nitrogenous compounds, chromones, flavonoids and 4α-methyl steroid. Among them, the primary bioactive constituents are believed to be present in the triterpene glycoside fraction. To date, investigation of seven Cimicifuga spp. plants led to the identification of more than 457 compounds. Years of pharmacological research proved that the crude extracts and certain pure compounds obtained from Cimicifuga exhibited menopausal syndrome-treatment, anti-osteoporosis, antiviral, antitumor, antioxidant and antiangiogenic activities. On the other hand, Cimicifuga plant-induced toxicities of liver, cardiovascular, central and peripheral nervous systems have also been reported. Therefore, safety consideration should be placed into a high priority for herbal medicine Cimicifuga therapy in the early stages of development and clinical trials.

CONCLUSIONS

This review presents information on botany, medicinal resources, and traditional medicinal history of some Cimicifuga plants. Modern pharmacology researchers have validated many traditional uses of Cimicifuga species. As the quality control and safety assessment of Cimicifuga plants is still incomplete, only a small part of the plant is permitted to be used as medicines. Expansion of medicinal resources in Cimicifuga is urgently needed to enable its full use. Currently research primarily focuses on the triterpenoid glycosides but there are many other types of compounds which may possess new biological activities however the systematic studies of these compounds are lacking. Extensive study is required on Cimicifuga plant before it can be fully used in clinics as a potent drug candidate.

Herbal plants and plant preparations as remedial approach for viral diseases

Herbal plants, plant preparations and phytoconstituents have proved useful in attenuating infectious conditions and were the only remedies available, till the advent of antibiotics (many being of plant origin themselves). Among infectious diseases, viral diseases in particular, remain the leading cause of death in humans globally. A variety of phytoconstituents derived from medicinal herbs have been extensively studied for antiviral activity. Based on this rationale, an online search was performed, which helped to identify a large number of plant species harboring antiviral molecules. These herbal sources have been reported individually or in combinations across a large number of citations studied. Activities against rabies virus, Human immunodeficiency virus, Chandipura virus, Japanese Encephalitis Virus, Enterovirus, Influenza A/H1N1 and other influenza viruses were discovered during the literature search. This review includes all such plant species exhibiting antiviral properties. The review also encompasses composition and methodologies of preparing various antiviral formulations around the globe. An elaborate section on the formulations filed for patent registration, along with non-patented formulations, has also been included in this article. To conclude, herbal sources provide researchers enormous scope to explore and bring out viable alternatives against viral diseases, considering non-availability of suitable drug candidates and increasing resistance to existing drug molecules for many emerging and re-emerging viral diseases.

Validation of Antiviral Potential of Herbal Ethnomedicine

Natural products are the basis of treatment since the dawn of human civilization, and modern medicine has gradually developed, over the years, by scientific and observational efforts from traditional medicine. Today most of the synthetic drugs showed adverse and unacceptable side effects, however, impressive bioactivities with reduced toxicities were reported for many botanicals against several chronic or difficult-to-treat diseases. A whole range of viral diseases including human immunodeficiency virus/acquired immunodeficiency syndrome, severe acute respiratory syndrome, Rabies, Dengue, and Herpes need effective drugs. Considerable research has been carried out on the pharmacognosy, chemistry, pharmacology, and therapeutics of traditional medicines of diverse cultures, and many pharmaceutical companies have renewed their strategies for antiviral drug development where no effective drugs or vaccine exist. Thus, phytochemicals with antiviral potentials need to be studied in depth with standardization, chemical isolation, effectivity, molecular mechanism, along with in vivo toxicity and efficacy to reduce cost and time. This review will portray the scientific approaches and methodologies used for the development of antiviral leads from traditional medicines against selected genetically and functionally diverse viral infections.

Antiviral natural products and herbal medicines

Viral infections play an important role in human diseases, and recent outbreaks in the advent of globalization and ease of travel have underscored their prevention as a critical issue in safeguarding public health. Despite the progress made in immunization and drug development, many viruses lack preventive vaccines and efficient antiviral therapies, which are often beset by the generation of viral escape mutants. Thus, identifying novel antiviral drugs is of critical importance and natural products are an excellent source for such discoveries. In this mini-review, we summarize the antiviral effects reported for several natural products and herbal medicines.

Antiviral activity of carnosic acid against respiratory syncytial virus

Background

Human respiratory syncytial virus (hRSV) is a leading cause of severe lower respiratory infection and a major public health threat worldwide. To date, no vaccine or effective therapeutic agent has been developed. In a screen for potential therapeutic agents against hRSV, we discovered that an extract of Rosmarinus officinalis exerted a strong inhibitory effect against hRSV infection. Subsequent studies identified carnosic acid as a bioactive constituent responsible for anti-hRSV activity. Carnosic acid has been shown to exhibit potent antioxidant and anti-cancer activities. Anti-RSV activity of carnosic acid was further investigated in this study.

Methods

Effects of extracts from various plants and subfractions from R. officinalis on hRSV replication were determined by microneutralization assay and plaque assay. Several constituents were isolated from ethyl acetate fraction of R. officinalis and their anti-RSV activities were assessed by plaque assay as well as reverse-transcription quantitative PCR to determine the synthesis of viral RNAs.

Results

Among the tested bioactive constituents of R. officinalis, carnosic acid displayed the most potent anti-hRSV activity and was effective against both A- and B-type viruses. Carnosic acid efficiently suppressed the replication of hRSV in a concentration-dependent manner. Carnosic acid effectively suppressed viral gene expression without inducing type-I interferon production or affecting cell viability, suggesting that it may directly affect viral factors. A time course analysis showed that addition of carnosic acid 8 hours after infection still effectively blocked the expression of hRSV genes, further suggesting that carnosic acid directly inhibited the replication of hRSV.

Conclusions

The current study demonstrates that carnosic acid, a natural compound that has already been shown to be safe for human consumption, has anti-viral activity against hRSV, efficiently blocking the replication of this virus. Carnosic acid inhibited both A- and B- type hRSV, while it did not affect the replication of influenza A virus, suggesting that its antiviral activity is hRSV-specific. Collectively, this study suggests the need for further evaluation of carnosic acid as a potential treatment for hRSV.

Antiviral Activity ofFolium IsatidisDerived ExtractsIn VitroandIn Vivo

Folium isatidis is a native Chinese herbaceous plant widely used for medicinal purposes for thousands of years. However, few studies have focused on the leaves of Isatis indigotica. In this report, we isolated a series of four fractions (I–IV) from Folium isatidis and explored the antiviral activity of each tested extract. The extracts were active against a panel of RNA and DNA viruses in vitro, namely influenza A virus (IAV), coxsackie virus B3 (CVB3), respiratory syncytial virus (RSV), and adenovirus type 7 (Ad-7). Oral administration of 200 mg/kg/d of fraction III in mice exerted strong antiviral effects in viral replication, accompanied by prolonged survival rate, attenuated lung tissue damage as well as significant reductions in pulmonary virus titers and lung index. Our results provide the first biochemical evidence that Folium isatidis and its extracts could be used as potential antiviral agent in the postexposure prophylaxis for multiple viral infections.

Anti-Viral Activity of Water Extract of Paeonia lactiflora Pallas Against Human Respiratory Syncytial Virus in Human Respiratory Tract Cell Lines

Paeonia lactiflora Pallas (P. lactiflora, Ranunculaceae) is a common ingredient of Sheng-Ma-Ge-Gen-Tang (SMGGT; Shoma-kakkon-to) and Ge-Gen-Tang (GGT; kakkon-to). SMGGT and GGT are different prescriptions of traditional Chinese medicine with different ingredients designed for airway symptoms. Both SMGGT and GGT have anti-viral activity against human respiratory syncytial virus (HRSV). Therefore, P. lactiflora was hypothesized to be the effective ingredient of both SMGGT and GGT against HRSV. However, P. lactiflora does not have any proven antiviral activity. This study used both human upper (Human larynx epidermoid carcinoma cell line, HEp-2) and lower (human lung carcinoma cell line, A549) respiratory tract cells to test the hypothesis that a hot water extract of P. lactiflora could effectively inhibit plaque formation induced by HRSV infection. The ability of P. lactiflora to stimulate anti-viral cytokines was evaluated by enzyme-linked immunosorbent assay (ELISA). The results showed that P. lactiflora was time-dependently and dose-dependently effective against HRSV in HEp-2 and A549 cells, particularly supplemented before viral inoculation (p < 0.0001). 10 μg/ml P. lactiflora had a comparable anti-HRSV activity with 10 μg/ml ribavirin, a broad-spectrum antiviral agent. P. lactiflora was dose-dependently effective against viral attachment (p < 0.0001), with a better effect on A549 cells (p < 0.0001). P. lactiflora was time-dependently (p < 0.0001) and dose-dependently (p < 0.0001) effective against viral penetration. Moreover, P. lactiflora stimulated IFN-β secretion without any effect on TNF-α secretion. Therefore, P. lactiflora could be beneficial at preventing HRSV infection by inhibiting viral attachment, internalization, and stimulating IFN secretion.