Geraniin extracted from the rind of Nephelium lappaceum binds to dengue virus type-2 envelope protein and inhibits early stage of virus replication

Dengue virus pathogenesis and host molecular machineries

Dengue viruses (DENV) are positive-stranded RNA viruses belonging to the Flaviviridae family. DENV is the causative agent of dengue, the most rapidly spreading viral disease transmitted by mosquitoes. Each year, millions of people contract the virus through bites from infected female mosquitoes of the Aedes species. In the majority of individuals, the infection is asymptomatic, and the immune system successfully manages to control virus replication within a few days. Symptomatic individuals may present with a mild fever (Dengue fever or DF) that may or may not progress to a more critical disease termed Dengue hemorrhagic fever (DHF) or the fatal Dengue shock syndrome (DSS). In the absence of a universally accepted prophylactic vaccine or therapeutic drug, treatment is mostly restricted to supportive measures. Similar to many other viruses that induce acute illness, DENV has developed several ways to modulate host metabolism to create an environment conducive to genome replication and the dissemination of viral progeny. To search for new therapeutic options, understanding the underlying host-virus regulatory system involved in various biological processes of the viral life cycle is essential. This review aims to summarize the complex interaction between DENV and the host cellular machinery, comprising regulatory mechanisms at various molecular levels such as epigenetic modulation of the host genome, transcription of host genes, translation of viral and host mRNAs, post-transcriptional regulation of the host transcriptome, post-translational regulation of viral proteins, and pathways involved in protein degradation.

Geraniin Alleviates Inflammation in Caco-2 Cells and Dextran Sulfate Sodium-Induced Colitis Mice by Targeting IL-1β

IL-1β is an important cytokine implicated in the progression of inflammatory bowel disease (IBD) and intestinal barrier dysfunction. The polyphenolic compound, geraniin, possesses bioactive properties, such as antitumor, antioxidant, anti-inflammatory, antihypertensive, and antiviral activities; however, its IL-1β-targeted anticolitis activity remains unclear. Here, we evaluated the inhibitory effect of geraniin in IL-1β-stimulated Caco-2 cells and a dextran sulfate sodium (DSS)-induced colitis mouse model. Geraniin blocked the interaction between IL-1β and IL-1R by directly binding to IL-1β and inhibited the IL-1β activity. It suppressed IL-1β-induced intestinal tight junction damage in human Caco-2 cells by inhibiting IL-1β-mediated MAPK, NF-kB, and MLC activation. Moreover, geraniin administration effectively reduced colitis symptoms and attenuated intestinal barrier injury in mice by suppressing elevated intestinal permeability and restoring tight junction protein expression through the inhibition of MAPK, NF-kB, and MLC activation. Thus, geraniin exhibits anti-IL-1β activity and anticolitis effect by hindering the IL-1β and IL-1R interaction and may be a promising therapeutic anti-IL-1β agent for IBD treatment.

Dengue havoc: overview and eco-friendly strategies to forestall the current epidemic

Dengue fever is a mosquito-borne viral illness that affects over 100 nations around the world, including Africa, America, the Eastern Mediterranean, Southeast Asia, and the Western Pacific. Those who get infected by virus for the second time are at greater risk of having persistent dengue symptoms. Dengue fever has yet to be treated with a long-lasting vaccination or medication. Because of their ease of use, mosquito repellents have become popular as a dengue prevention technique. However, this has resulted in environmental degradation and harm, as well as bioaccumulation and biomagnification of hazardous residues in the ecosystem. Synthetic pesticides have caused a plethora of serious problems that were not foreseen when they were originally introduced. The harm caused by the allopathic medications/synthetic pesticides/chemical mosquito repellents has paved the door to employment of eco-friendly/green approaches in order to reduce dengue cases while protecting the integrity of the nearby environment too. Since the cases of dengue have become rampant these days, hence, starting the medication obtained from green approaches as soon as the disease is detected is advisable. In the present paper, we recommend environmentally friendly dengue management strategies, which, when combined with a reasonable number of vector control approaches, may help to avoid the dengue havoc as well as help in maintaining the integrity of the ecosystem.

Vector-Transmitted Flaviviruses: An Antiviral Molecules Overview

Flaviviruses cause numerous pathologies in humans across a broad clinical spectrum with potentially severe clinical manifestations, including hemorrhagic and neurological disorders. Among human flaviviruses, some viral proteins show high conservation and are good candidates as targets for drug design. From an epidemiological point of view, flaviviruses cause more than 400 million cases of infection worldwide each year. In particular, the Yellow Fever, dengue, West Nile, and Zika viruses have high morbidity and mortality-about an estimated 20,000 deaths per year. As they depend on human vectors, they have expanded their geographical range in recent years due to altered climatic and social conditions. Despite these epidemiological and clinical premises, there are limited antiviral treatments for these infections. In this review, we describe the major compounds that are currently under evaluation for the treatment of flavivirus infections and the challenges faced during clinical trials, outlining their mechanisms of action in order to present an overview of ongoing studies. According to our review, the absence of approved antivirals for flaviviruses led to in vitro and in vivo experiments aimed at identifying compounds that can interfere with one or more viral cycle steps. Still, the currently unavailability of approved antivirals poses a significant public health issue.

Repurposing of approved antivirals against dengue virus serotypes: an in silico and in vitro mechanistic study

Dengue is an emerging, mosquito-borne viral disease of international public health concern. Dengue is endemic in more than 100 countries across the world. However, there are no clinically approved antivirals for its cure. Drug repurposing proves to be an efficient alternative to conventional drug discovery approaches in this regard, as approved drugs with an established safety profile are tested for new indications, which circumvents several time-consuming experiments. In the present study, eight approved RNA-dependent RNA polymerase inhibitors of Hepatitis C virus were virtually screened against the Dengue virus polymerase protein, and their antiviral activity was assessed in vitro. Schrödinger software was used for in silico screening, where the compounds were passed through several hierarchical filters. Among the eight compounds, dasabuvir was finally selected for in vitro cytotoxicity and antiviral screening. Cytotoxicity profiling of dasabuvir in Vero cells revealed changes in cellular morphology, cell aggregation, and detachment at 50 μM. Based on these results, four noncytotoxic concentrations of dasabuvir (0.1, 0.25, 0.5, and 1 µM) were selected for antiviral screening against DENV-2 under three experimental conditions: pre-infection, co-infection, and post-infection treatment, by plaque reduction assay. Viral plaques were reduced significantly (p < 0.05) in the co-infection and post-infection treatment regimens; however, no reduction was observed in the pretreatment group. This indicated a possible interference of dasabuvir with NS5 RdRp, as seen from in silico interaction studies, translating into a reduction in virus plaques. Such studies reiterate the usefulness of drug repurposing as a viable strategy in antiviral drug discovery. In this drug repurposing study, dasabuvir, a known anti-hepatitis C drug, was selected through virtual screening and assessed for its anti-dengue activity.

Identification of an effective fraction from Ampelopsis Radix with anti-dengue virus activities in vitro and in vivo

ETHNOPHARMACOLOGICAL RELEVANCE

Dengue virus (DENV) infection is a global public health issue without effective therapeutic interventions. Chinese medicine with heat-clearing and detoxifying properties has been frequently used in the treatment of viral infection. Ampelopsis Radix (AR) is a traditional Chinese medicine for clearing heat and detoxification that has been widely used in the prevention and treatment of infectious diseases. However, no studies on the effects of AR against viral infection have been reported, thus far.

AIM OF THE STUDY

To explore the anti-DENV activities of the fraction (AR-1) obtained from AR both in vitro and in vivo.

MATERIALS AND METHODS

The chemical composition of AR-1 was identified by liquid chromatography-tandem MS (LC‒MS/MS). The antiviral activities of AR-1 were studied in baby hamster kidney fibroblast BHK-21 cells, ICR suckling mice and induction of interferon α/β (IFN-α/β) and IFN-γ R^-/- (AG129) mice.

RESULTS

Based on LC‒MS/MS analysis, 60 compounds (including flavonoids, phenols, anthraquinones, alkaloids and other types) were tentatively characterized from AR-1. AR-1 inhibited the cytopathic effect, the production of progeny virus and the synthesis of viral RNA and proteins by blocking DENV-2 binding to BHK-21 cells. Moreover, AR-1 significantly attenuated weight loss, decreased clinical scores and prolonged the survival of DENV-infected ICR suckling mice. Critically, the viral load in blood, brain and kidney tissues and the pathological changes in brain were remarkably alleviated after AR-1 treatment. Further study on AG129 mice showed that AR-1 obviously improved the clinical manifestations and survival rate, reduced viremia, attenuated gastric distension and relieved the pathological lesions caused by DENV.

CONCLUSIONS

In summary, this is the first report that AR-1 exhibits anti-DENV effects both in vitro and in vivo, which suggests that AR-1 may be developed as a therapeutic candidate against DENV infection.

Seaweeds and Corals from the Brazilian Coast: Review on Biotechnological Potential and Environmental Aspects

Brazil has a megadiversity that includes marine species that are distributed along 800 km of shoreline. This biodiversity status holds promising biotechnological potential. Marine organisms are important sources of novel chemical species, with applications in the pharmaceutical, cosmetic, chemical, and nutraceutical fields. However, ecological pressures derived from anthropogenic actions, including the bioaccumulation of potentially toxic elements and microplastics, impact promising species. This review describes the current status of the biotechnological and environmental aspects of seaweeds and corals from the Brazilian coast, including publications from the last 5 years (from January 2018 to December 2022). The search was conducted in the main public databases (PubChem, PubMed, Science Direct, and Google Scholar) and in the Espacenet database (European Patent Office-EPO) and the Brazilian National Property Institute (INPI). Bioprospecting studies were reported for seventy-one seaweed species and fifteen corals, but few targeted the isolation of compounds. The antioxidant potential was the most investigated biological activity. Despite being potential sources of macro- and microelements, there is a literature gap regarding the presence of potentially toxic elements and other emergent contaminants, such as microplastics, in seaweeds and corals from the Brazilian coast.

Specialized metabolites from plants as a source of new multi-target antiviral drugs: a systematic review

Viral infections have always been the main global health challenge, as several potentially lethal viruses, including the hepatitis virus, herpes virus, and influenza virus, have affected human health for decades. Unfortunately, most licensed antiviral drugs are characterized by many adverse reactions and, in the long-term therapy, also develop viral resistance; for these reasons, researchers have focused their attention on investigating potential antiviral molecules from plants. Natural resources indeed offer a variety of specialized therapeutic metabolites that have been demonstrated to inhibit viral entry into the host cells and replication through the regulation of viral absorption, cell receptor binding, and competition for the activation of intracellular signaling pathways. Many active phytochemicals, including flavonoids, lignans, terpenoids, coumarins, saponins, alkaloids, etc., have been identified as potential candidates for preventing and treating viral infections. Using a systematic approach, this review summarises the knowledge obtained to date on the in vivo antiviral activity of specialized metabolites extracted from plant matrices by focusing on their mechanism of action.

Molecular Mechanisms of Antiviral Agents against Dengue Virus

Dengue is a major global health threat causing 390 million dengue infections and 25,000 deaths annually. The lack of efficacy of the licensed Dengvaxia vaccine and the absence of a clinically approved antiviral against dengue virus (DENV) drive the urgent demand for the development of novel anti-DENV therapeutics. Various antiviral agents have been developed and investigated for their anti-DENV activities. This review discusses the mechanisms of action employed by various antiviral agents against DENV. The development of host-directed antivirals targeting host receptors and direct-acting antivirals targeting DENV structural and non-structural proteins are reviewed. In addition, the development of antivirals that target different stages during post-infection such as viral replication, viral maturation, and viral assembly are reviewed. Antiviral agents designed based on these molecular mechanisms of action could lead to the discovery and development of novel anti-DENV therapeutics for the treatment of dengue infections. Evaluations of combinations of antiviral drugs with different mechanisms of action could also lead to the development of synergistic drug combinations for the treatment of dengue at any stage of the infection.

Development of novel antiviral peptides against dengue serotypes 1-4

Dengue infections pose a critical threat to public health worldwide. Since there are no clinically approved antiviral drugs to treat dengue infections caused by the four dengue virus (DENV) serotypes, there is an urgent need to develop effective antivirals. Peptides are promising antiviral candidates due to their specificity and non-toxic properties. The DENV envelope (E) protein was selected for the design of antiviral peptides due to its importance in receptor binding and viral fusion to the host cell membrane. Twelve novel peptides were designed to mimic regions containing critical amino acid residues of the DENV E protein required for interaction with the host. A total of four peptides were identified to exhibit potent inhibitory effects against at least three or all four DENV serotypes. Peptide 3 demonstrated all three modes of action: cell protection and inhibition of post-infection against all four DENV serotypes, whereas direct virus-inactivating effects were only observed against DENV-2, 3, and 4. Peptide 4 showed good direct virus-inactivating effects against DENV-2 (74.26%) as well as good inhibitions of DENV-1 (80.37%) and DENV-4 (72.22%) during the post-infection stage. Peptide 5 exhibited direct virus-inactivating effects against all four DENV serotypes, albeit at lower inhibition levels against DENV-1 and DENV-3. It also exhibited highly significant inhibition of DENV-4 (89.31%) during post-infection. Truncated peptide 5F which was derived from peptide 5 showed more significant inhibition of DENV-4 (91.58%) during post-infection and good direct virus-inactivating effects against DENV-2 (77.55%) at a lower concentration of 100 μM. Peptide 3 could be considered as the best antiviral candidate for pre- and post-infection treatments of DENV infections in regions with four circulating dengue serotypes. However, if the most predominant dengue serotype for a particular region could be identified, peptides with significantly high antiviral activities against that particular dengue serotype could serve as more suitable antiviral candidates. Thus, peptide 5F serves as a more suitable antiviral candidate for post-infection treatment against DENV-4.

Immuno-informatics guided designing of a multi-epitope vaccine against Dengue and Zika

Dengue and zika are amongst the most prevalent mosquito-borne diseases caused by closely related members Dengue virus (DENV) and Zika virus (ZIKV), respectively, of the Flaviviridae family. DENV and ZIKV have been reported to co-infect several people, resulting in fatalities across the world. A vaccine that can safeguard against both these pathogens concurrently, can offer several advantages. This study has employed immuno-informatics for devising a multi-epitope, multi-pathogenic vaccine against both these viruses. Since, the two viruses share a common vector source, whose salivary components are reported to aid viral pathogenesis; antigenic salivary proteins from Aedes aegypti were also incorporated into the design of the vaccine along with conserved structural and non-structural viral proteins. Conserved B- and T-cell epitopes were identified for all the selected antigenic proteins. These epitopes were merged and further supplemented with β-defensin as an adjuvant, to yield an immunogenic vaccine construct. In-silico 3D modeling and structural validation of the vaccine construct was conducted, followed by its molecular docking and molecular dynamics simulation studies with human TLR2. Immune simulation study was also performed, and it further provided support that the designed vaccine can mount an effective immune response and hence provide protection against both DENV and ZIKV. Communicated by Ramaswamy H. Sarma.

Biological Characterization and Quantification of Rambutan (Nephelium lappaceum L.) Peel Extract as a Potential Source of Valuable Minerals and Ellagitannins for Industrial Applications

This study extracted ellagitannins from rambutan peel using the Soxhlet technique. The extract was further partitioned and fractionated to get extract rich in ellagitannin and geraniin, respectively. The partitioning of the extract significantly increased total phenolic content (TPC) by 36.3% and its biological properties. Mineral elements such as Ca, Cr, Cu, Fe, K, Mg, Mn, Na, Ni, and Zn were identified in both peel and extract. Ellagitannins such as geraniin and corilagin with metabolites (gallic acid and ellagic acid) were identified as the major compounds. Analysis of antioxidant activities shows that the ellagitannin rich extract is as powerful as vitamin C. Geraniin was the main contributor to the free radical scavenging activity. The study also revealed that extract with a fraction rich in geraniin has antioxidant activity equivalent to commercial geraniin (1.56 ± 0.11 Trolox equivalent g/g). It also showed low cytotoxicity on fibroblast L929 cells, moderate tyrosinase activity, and good efficacy against Staphylococcus aureus, Staphylococcus epidermidis, and Cutibacterium acnes strains. Successive fractionation of the extract is a promising technique to produce geraniin rich fractions with enhanced antioxidant property. Rambutan peel, as a natural product, is a good source of mineral elements and biologically active compounds for pharmaceutical, nutraceutical, and cosmetic formulations.

Therapeutic Potential of Medicinal Plants against Dengue Infection: A Mechanistic Viewpoint

Dengue is a tropical disease caused by the Dengue virus (DENV), a positive-sense, single stranded RNA virus of the family Flaviviridae, which is transmitted by Aedes mosquitoes. The occurrence of dengue has grown dramatically around the globe in recent decades, and it is rapidly becoming a global burden. Furthermore, all four DENV serotypes cocirculate and create a problematic hyperendemic situation. Characteristic symptoms range from being asymptomatic, dengue fever to life-threatening complications such as hemorrhagic fever and shock. Apart from the inherent virulence of the virus strain, a dysregulated host immune response makes the condition worse. Currently, there is no highly recommended vaccine or therapeutic agent against dengue. With the advent of virus strains resistant to antiviral agents, there is a constant need for new therapies to be developed. Since time immemorial, human civilization has utilized plants in traditional medicine to treat various diseases, including infectious viral diseases. With the advancement in molecular biology, cell biology techniques, and bioinformatics, recent studies have tried to provide scientific evidence and determine the mechanism of anti-dengue activity of various plant extracts and plant-derived agents. The current Review consolidates the studies on the last 20 years of in vitro and in vivo experiments on the ethnomedicinal plants used against the dengue virus. Several active phytoconstituents like quercetin, castanospermine, α-mangostin, schisandrin-A, hirsutin have been found to be promising to inhibition of all the four DENV serotypes. However, novel therapeutics need to be reassessed in relevant cells using high-throughput techniques. Further, in vivo dose optimization for the immunomodulatory and antiviral activity should be examined on a vast sample size. Such a Review should help take the knowledge forward, validate it, and use medicinal plants in different combinations targeting multiple stages of virus infection for more effective multipronged therapy against dengue infection.

Studies on the antiviral activity of chebulinic acid against dengue and chikungunya viruses and in silico investigation of its mechanism of inhibition

Chebulinic acid (CA), originally isolated from the flower extract of the plant Terminalia chebula, has been shown to inhibit infection of herpes simplex virus-2 (HSV-2), suggestively by inhibiting the host entry step of viral infection. Like HSV-2, the dengue virus (DENV) and chikungunya virus (CHIKV) also use receptor glycosaminoglycans (GAG) to gain host entry, therefore, the activity of CA was tested against these viruses. Co-treatment of 8 µM CA with DENV-2 caused 2 log decrease in the virus titer (4.0 log₁₀FFU/mL) at 120 h post infection, compared to virus control (5.95 log₁₀FFU/mL). In contrast, no inhibitory effect of CA was observed against CHIKV infection under any condition. The mechanism of action of CA was investigated in silico by employing DENV-2 and CHIKV envelope glycoproteins. During docking, CA demonstrated equivalent binding at multiple sites on DENV-2 envelope protein, including GAG binding site, which have previously been reported to play a crucial role in host attachment and fusion, indicating blocking of these sites. However, CA did not show binding to the GAG binding site on envelope protein-2 of CHIKV. The in vitro and in silico findings suggest that CA possesses the ability to inhibit DENV-2 infection at the entry stage of its infection cycle and may be developed as a potential therapeutic agent against it.

Cranberry Pomace Extract Exerts Antiviral Activity against Zika and Dengue Virus at Safe Doses for Adult Zebrafish

Mosquito-borne dengue virus (DENV) and zika virus (ZIKV) infections constitute a global health emergency. Antivirals directly targeting the virus infectious cycle are still needed to prevent dengue hemorrhagic fever and congenital zika syndrome. In the present study, we demonstrated that Cranberry Pomace (CP) extract, a polyphenol-rich agrifood byproduct recovered following cranberry juice extraction, blocks DENV and ZIKV infection in human Huh7.5 and A549 cell lines, respectively, in non-cytotoxic concentrations. Our virological assays identified CP extract as a potential inhibitor of virus entry into the host-cell by acting directly on viral particles, thus preventing their attachment to the cell surface. At effective antiviral doses, CP extract proved safe and tolerable in a zebrafish model. In conclusion, polyphenol-rich agrifood byproducts such as berry extracts are a promising source of safe and naturally derived nutraceutical antivirals that target medically important pathogens.

Cyanobacterial metabolites as novel drug candidates in corona viral therapies: A review

Most of the medical and nonmedical research labs, all around the world, are racing against time to produce an effective vaccine or an antiviral medicine for coronavirus disease 2019 (COVID‐19). Conventional medicines and novel nano‐materials including chemical and herbal‐based compounds are all into positive trials toward coronaviruses and other pandemic infections. Among them, natural immune boosters have attracted physicians because of their longevity and reliability for fewer side effects. This is a review article with a detailed picture of an unexplored antiviral source with maximum potency in curing viral infections. Cyanobacteriae have been known for centuries and are rich in secondary metabolites of proteins, biopeptides, and polysaccharides for prominent antiviral action against chest infections. But detailed exploratory research is required to purify, scale‐up, and commercialize the pharmacologically active agents from these drug reserves.

Traditional Knowledge to Contemporary Medication in the Treatment of Infectious Disease Dengue: A Review

Dengue has become a worldwide affliction despite incessant efforts to search for a cure for this long-lived disease. Optimistic consequences for dengue vaccine are implausible as the efficiency is tied to previous dengue virus (DENV) exposure and a very high cost is required for large-scale production of vaccine. Medicinal plants are idyllic substitutes to fight DENV infection since they constitute important components of traditional medicine and show antiviral properties, although the mechanism behind the action of bioactive compounds to obstruct viral replication is less explored and yet to be discovered. This review includes the existing traditional knowledge on how DENV infects and multiplies in the host cells, conscripting different medicinal plants that obtained bioactive compounds with anti-dengue properties, and the probable mechanism on how bioactive compounds modulate the host immune system during DENV infection. Moreover, different plant species having such bioactive compounds reported for anti-DENV efficiency should be validated scientifically via different in vitro and in vivo studies.

Geraniin inhibits whole blood IFN-γ and IL-6 and promotes IL-1β and IL-8, and stimulates calcium-dependent and sucrose-sensitive erythrocyte death

Correlations between circulating cytokine levels and disease states are well established, and pharmacological modulation of the immune response is thus an important aspect of the assessment of investigational new drugs. Moreover, chemotherapy-related anemia is a major obstacle in cancer treatment. Geraniin (GRN), a tannin extracted from Geranium and other plants, possesses promising antitumor potential. However, the effect of GRN on whole blood (WB) cytokine response and RBC physiology remains unexplored. Heparinized blood from consented, healthy adults was challenged with 100 ng/mL of lipopolysaccharide (LPS) with and without pretreatment with 10 μM of GRN for 24 h at 37 °C, and tumor necrosis factor-α (TNF-α), interferon-γ (IFN-γ), interleukin-1β (IL-1β), IL-6, IL-8, and IL-10 were assayed by ELISA. Moreover, single-cell RBC suspensions were treated with 5-100 μM of GRN for 24 or 48 h at 37 °C and cytotoxicity and canonical eryptotic markers were examined by flow cytometry. It was revealed that GRN significantly attenuated LPS-induced IFN-γ levels, increased IL-1β, decreased IL-6 only in absence of LPS, and aggravated LPS-induced IL-8 while together with LPS significantly diminished IL-10. Furthermore, GRN induced dose-responsive, Ca²⁺-dependent, and sucrose-sensitive hemolysis, along with phosphatidylserine exposure and Ca²⁺ accumulation with no appreciable cell shrinkage or oxidative damage. GRN was also selectively toxic to platelets, significantly delayed reticulocyte maturation, and significantly disrupted leukocyte proportions. In conclusion, GRN regulates the WB cytokine response and promotes premature hemolysis and eryptosis. This study provides insights into the therapeutic utility of GRN in a highly relevant cellular model system.

Geraniin inhibits cell growth and promoted autophagy-mediated cell death in the nasopharyngeal cancer C666-1 cells

Background

Nasopharyngeal carcinoma (NPC) is a rare malignant tumor developing from epithelial linings of nasopharynx, and 10–50 out of 100,000 NPC cases were recorded globally particularly in the Asian countries.

Methodology

The cytotoxicity of geraniin against the NPC C666-1 cells were analyzed using MTT assay. The influences of geraniin on the C666-1 cell viability with the presence of ROS and apoptosis inhibitors were also studied. The expressions of PI3K, Akt, mTOR, and autophagic markers LC3, ATG7, P62/SQSTM1 expressions in the C666-1 cells were studied by western blotting analysis. The ROS production was assayed using DCFH-DA staining. The immunofluorescence assay was performed to detect the NF-κB and β-catenin expressions in the C666-1 cells.

Results

The cell viability of C666-1 cells were appreciably prevented by the geraniin. The geraniin treatment also inhibited the C666-1 cell growth with the presence of apoptotic inhibitor Z-VAD-FMK. The geraniin-treatment effectively improved the ROS production and inhibited the NF-κB and β-catenin expressions in the C666-1 cells. Geraniin appreciably modulated the PI3K/Akt/mTOR signaling axis and improved the autophagy-mediated cell death via improving the autophagic markers LC3 and ATG7 expressions in the C666-1 cells.

Conclusion

In conclusion, our results proved that geraniin inhibits C666-1 cell growth and initiated autophagy-mediated cell death via modulating PI3K/Akt/mTOR cascade and improving LC3 and ATG7 expressions in the C666-1. Geraniin and it could be a hopeful and efficient candidate to treat the human NPC in the future.

A Preliminary Investigation on the Antiviral Activities of the Philippine Marshmint (Mentha arvensis) Leaf Extracts against Dengue Virus Serotype 2 In Vitro

In this study, we investigated the antiviral activity of lyophilized crude leaf extracts of the Philippine marshmint (Mentha arvensis L., commonly called yerba buena) against DENV-2 in vitro. The plant specimen was authenticated by DNA barcoding analysis using standard primers for amplification of rbcL, matK, ITS1, ITS2 and trnH-psbA. Aqueous, methanol and ethanol leaf extracts were prepared, and lyophilized prior to testing for its cytotoxicity and antiviral activities. All extracts presented cytotoxic activities against Vero cells in a dose-dependent manner. Half maximal cytotoxicity concentration (CC50) was calculated at 2,889.60 µg/mL for the aqueous extract, 1,928.62 µg/mL for the methanol extract, and 3,380.30 µg/mL for the ethanol extract. Antiviral activities assessed by plaque reduction assay revealed reduced DENV-2 viral infectivity, with the ethanol extract observed to have the strongest activity decreasing plaque numbers by 62% relative to the control. The methanol extract was observed to be most effective when added before infection causing 72% reduction in plaque numbers, whereas none of the extracts inhibited plaque formation by more than 40% when added after infection. DENV-2 NS1 antigen production was significantly reduced by the methanol extract, while viral RNA levels were also decreased as determined by real time RT-PCR. Phytochemical analysis revealed the presence of flavonoids, phenolics, tannins, proteins, reducing sugars and saponins. Our preliminary results are promising, however, it should be interpreted with caution as further studies are needed to establish its potential therapeutic application against dengue infection.

Production, Transmission, Pathogenesis, and Control of Dengue Virus: A Literature-Based Undivided Perspective

Dengue remains one of the most serious and widespread mosquito-borne viral infections in human beings, with serious health problems or even death. About 50 to 100 million people are newly infected annually, with almost 2.5 billion people living at risk and resulting in 20,000 deaths. Dengue virus infection is especially transmitted through bites of Aedes mosquitos, hugely spread in tropical and subtropical environments, mostly found in urban and semiurban areas. Unfortunately, there is no particular therapeutic approach, but prevention, adequate consciousness, detection at earlier stage of viral infection, and appropriate medical care can lower the fatality rates. This review offers a comprehensive view of production, transmission, pathogenesis, and control measures of the dengue virus and its vectors.

Berberine Inhibits Dengue Virus through Dual Mechanisms

Mosquito transmitted viruses, particularly those of the genus Flavivirus, are a significant healthcare burden worldwide, especially in tropical and sub-tropical areas. However, effective medicines for these viral infections remains lacking. Berberine (BBR) is an alkaloid found in some plants used in traditional medicines in Southeast Asia and elsewhere, and BBR has been shown to possess anti-viral activities. During a screen for potential application to mosquito transmitted viruses, BBR was shown to have virucidal activity against dengue virus (DENV; IC₅₀ 42.87 µM) as well as against Zika virus (IC₅₀ 11.42 µM) and chikungunya virus (IC₅₀ 14.21 µM). BBR was shown to have cellular effects that lead to an increase in cellular DENV E protein without a concomitant effect on DENV nonstructural proteins, suggesting an effect on viral particle formation or egress. While BBR was shown to have an effect of ERK1/2 activation this did not result in defects in viral egress mechanisms. The primary effect of BBR on viral production was likely to be through BBR acting through AMPK activation and disruption of lipid metabolism. Combined these results suggest that BBR has a dual effect on DENV infection, and BBR may have the potential for development as an anti-DENV antiviral.

Functional Insights into Silymarin as an Antiviral Agent against Enterovirus A71 (EV-A71)

Enterovirus A71 (EV-A71) is a major neurovirulent agent capable of causing severe hand, foot and mouth disease (HFMD) associated with neurological complications and death. Currently, no FDA-approved antiviral is available for the treatment of EV-A71 infections. The flavonoid silymarin was shown to exert virucidal effects, but the binding site on the capsid was unknown. In this study, the ligand interacting site of silymarin was determined in silico and validated in vitro. Moreover, the potential of EV-A71 to develop resistance against silymarin was further evaluated. Molecular docking of silymarin with the capsid of EV-A71 indicated that silymarin binds to viral protein 1 (VP1) of EV-A71, specifically at the GH loop of VP1. The in vitro binding of silymarin with VP1 of EV-A71 was validated using recombinant VP1 through ELISA competitive binding assay. Continuous passaging of EV-A71 in the presence of silymarin resulted in the emergence of a mutant carrying a substitution of isoleucine by threonine (I97T) at position 97 of the BC loop of EV-A71. The mutation was speculated to overcome the inhibitory effects of silymarin. This study provides functional insights into the underlying mechanism of EV-A71 inhibition by silymarin, but warrants further in vivo evaluation before being developed as a potential therapeutic agent.

Geraniin Inhibits the Entry of SARS-CoV-2 by Blocking the Interaction between Spike Protein RBD and Human ACE2 Receptor

The coronavirus disease 2019 (COVID-19) pandemic is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Despite the development of vaccines, the emergence of SARS-CoV-2 variants and the absence of effective therapeutics demand the continual investigation of COVID-19. Natural products containing active ingredients may be good therapeutic candidates. Here, we investigated the effectiveness of geraniin, the main ingredient in medical plants Elaeocarpus sylvestris var. ellipticus and Nephelium lappaceum, for treating COVID-19. The SARS-CoV-2 spike protein binds to the human angiotensin-converting enzyme 2 (hACE2) receptor to initiate virus entry into cells; viral entry may be an important target of COVID-19 therapeutics. Geraniin was found to effectively block the binding between the SARS-CoV-2 spike protein and hACE2 receptor in competitive enzyme-linked immunosorbent assay, suggesting that geraniin might inhibit the entry of SARS-CoV-2 into human epithelial cells. Geraniin also demonstrated a high affinity to both proteins despite a relatively lower equilibrium dissociation constant (K_D) for the spike protein (0.63 μM) than hACE2 receptor (1.12 μM), according to biolayer interferometry-based analysis. In silico analysis indicated geraniin’s interaction with the residues functionally important in the binding between the two proteins. Thus, geraniin is a promising therapeutic agent for COVID-19 by blocking SARS-CoV-2’s entry into human cells.

Phytoconstituents as Lead Compounds for Anti-Dengue Drug Discovery

Dengue is an arthropod-borne viral disease common in subtropical and tropical regions. The widespread use of traditional medicines in these regions for dengue fever (DF) has encouraged researchers to explore the therapeutic effect of herbs and their phytochemicals in dengue infection. Phytochemicals such as quercetin, baicalein, luteolin, oxindole alkaloids, celastrol and geraniin have shown significant inhibition of dengue virus in vitro. Many phytoconstituents have better selectivity index supporting their safety profile for future development. However, in vivo studies supporting therapeutic potency for these active phytoconstituents are limited. There is a need for studies translating anti-dengue profile of active phytoconstituents to find successful anti-dengue compounds.

Therapeutic potential of phytoconstituents of edible fruits in combating emerging viral infections

Plant-derived bioactive molecules display potential antiviral activity against various viral targets including mode of viral entry and its replication in host cells. Considering the challenges and search for antiviral agents, this review provides substantiated data on chemical constituents of edible fruits with promising antiviral activity. The bioactive constituents like naringenin, mangiferin, α-mangostin, geraniin, punicalagin, and lectins of edible fruits exhibit antiviral effect by inhibiting viral replication against IFV, DENV, polio, CHIKV, Zika, HIV, HSV, HBV, HCV, and SARS-CoV. The significance of edible fruit phytochemicals to block the virulence of various deadly viruses through their inhibitory action against the entry and replication of viral genetic makeup and proteins are discussed. In view of the antiviral property of active constituents of edible fruits which can strengthen the immune system and reduce oxidative stress, they are suggested to be diet supplements to combat various viral diseases including COVID-19. PRACTICAL APPLICATIONS: Considering the increasing threat of COVID-19, it is suggested to examine the therapeutic efficacy of existing antiviral molecules of edible fruits which may provide prophylactic and adjuvant therapy with their potential antioxidant, anti-inflammatory, and immune-modulatory effects. Several active molecules like geraniin, naringenin, (2R,4R)-1,2,4-trihydroxyheptadec-16-one, betacyanins, mangiferin, punicalagin, isomangiferin, procyanidin B2, quercetin, marmelide, jacalin lectin, banana lectin, and α-mangostin isolated from various edible fruits have showed promising antiviral properties against different pathogenic viruses. Especially flavonoid compounds extracted from edible fruits possess potential antiviral activity against a wide array of viruses like HIV-1, HSV-1 and 2, HCV, INF, dengue, yellow fever, NSV, and Zika virus infection. Hence taking such fruits or edible fruits and their constituents/compounds as dietary supplements could deliver adequate plasma levels in the body to optimize the cell and tissue levels and could lead to possible benefits for the preventive measures for this pandemic COVID-19 situation.

Viral inhibitors derived from macroalgae, microalgae, and cyanobacteria: A review of antiviral potential throughout pathogenesis

Viruses are abiotic obligate parasites utilizing complex mechanisms to hijack cellular machinery and reproduce, causing multiple harmful effects in the process. Viruses represent a growing global health concern; at the time of writing, COVID-19 has killed at least two million people around the world and devastated global economies. Lingering concern regarding the virus' prevalence yet hampers return to normalcy. While catastrophic in and of itself, COVID-19 further heralds in a new era of human-disease interaction characterized by the emergence of novel viruses from natural sources with heretofore unseen frequency. Due to deforestation, population growth, and climate change, we are encountering more viruses that can infect larger groups of people with greater ease and increasingly severe outcomes. The devastation of COVID-19 and forecasts of future human/disease interactions call for a creative reconsideration of global response to infectious disease. There is an urgent need for accessible, cost-effective antiviral (AV) drugs that can be mass-produced and widely distributed to large populations. Development of AV drugs should be informed by a thorough understanding of viral structure and function as well as human biology. To maximize efficacy, minimize cost, and reduce development of drug-resistance, these drugs would ideally operate through a varied set of mechanisms at multiple stages throughout the course of infection. Due to their abundance and diversity, natural compounds are ideal for such comprehensive therapeutic interventions. Promising sources of such drugs are found throughout nature; especially remarkable are the algae, a polyphyletic grouping of phototrophs that produce diverse bioactive compounds. While not much literature has been published on the subject, studies have shown that these compounds exert antiviral effects at different stages of viral pathogenesis. In this review, we follow the course of viral infection in the human body and evaluate the AV effects of algae-derived compounds at each stage. Specifically, we examine the AV activities of algae-derived compounds at the entry of viruses into the body, transport through the body via the lymph and blood, infection of target cells, and immune response. We discuss what is known about algae-derived compounds that may interfere with the infection pathways of SARS-CoV-2; and review which algae are promising sources for AV agents or AV precursors that, with further investigation, may yield life-saving drugs due to their diversity of mechanisms and exceptional pharmaceutical potential.

Dengue structural proteins as antiviral drug targets: Current status in the drug discovery & development

Dengue virus belongs to the class of RNA viruses and subclass of enveloped single-stranded positive-sense RNA virus. It causes dengue fever (DF), dengue hemorrhagic fever (DHF), or dengue shock syndrome (DSS), where DHF and DSS are life-threatening. Even though dengue is an age-old disease, it is still a mystery and continues to be a global threat. Numerous attempts have been carried out in the past few decades to eradicate the virus through vaccine and antiviral drugs, but still battle continues. In this review, the possible drug targets for discovery and development of potential antiviral drugs against structural proteins of dengue virus, the current development status of the antiviral drugs against dengue around the world, and challenges that need to be addressed to overcome the shortcomings in the process of drug discovery have been discussed.

[6]-Gingerol Inhibits Chikungunya Virus Infection by Suppressing Viral Replication

Chikungunya (CHIK) is a reemerging arboviral disease caused by chikungunya virus (CHIKV) infection. The disease is clinically hallmarked by prolonged debilitating joint pain. Currently, there is no specific antiviral medication nor commercial vaccine available for treatment of the disease, which makes the discovery or development of specific anti-CHIKV compounds a priority. Ginger (Zingiber officinale Roscoe) is widely known for its various health benefits. The compound [6]-gingerol is the main active ingredient found in ginger. This study sought to determine the potential of [6]-gingerol antiviral activity against CHIKV infection using in vitro human hepatocyte HepG2 cells. The antiviral activity mechanism was investigated using direct virucidal and four indirect (pre-, post-, full-, and prevention) treatment assays. [6]-Gingerol showed weak virucidal activity but significant indirect antiviral activity against CHIKV through post- and full treatment with IC₅₀ of 0.038 mM and 0.031 mM, respectively, without showing cell cytotoxicity. The results indicated that [6]-gingerol inhibits CHIKV infection through suppression of viral replication. Together, this study confirms the potential use of [6]-gingerol for CHIK antiviral compound.

Antiviral Role of Phenolic Compounds against Dengue Virus: A Review

Phenolic compounds have been related to multiple biological activities, and the antiviral effect of these compounds has been demonstrated in several viral models of public health concern. In this review, we show the antiviral role of phenolic compounds against dengue virus (DENV), the most widespread arbovirus globally that, after its re-emergence, has caused multiple epidemic outbreaks, especially in the last two years. Twenty phenolic compounds with anti-DENV activity are discussed, including the multiple mechanisms of action, such as those directed against viral particles or viral proteins, host proteins or pathways related to the productive replication viral cycle and the spread of the infection.

Current herbal medicine as an alternative treatment in dentistry: In vitro, in vivo and clinical studies

Since the time that human population comprehended the importance of general health maintenance and the burden of disease, there has been a search for healing properties in the natural environment. Herbal medicine is the use of plants with medical properties for prevention and treatment of conditions that can affect general health. Recently, a growing interest has been observed toward the use of traditional herbal medicine alongside synthetic modern drugs. Around 80% of the population, especially in developing countries relies on it for healthcare. Oral healthcare is considered a major part of general health. According to the world health organization (WHO), oral health is considered an important part of general health and quality of life. The utilization of natural medications for the management of pathologic oro-dental conditions can be a logical alternative to pharmaceutical methods due to their availability, low costs, and lower side effects. The current literature review aimed at exploration of the variety and extent of herbal products application in oral health maintenance including different fields of oral healthcare such as dental caries, periodontal maintenance, microbial infections, oral cancers, and inflammatory conditions.

PEG-b-PLGA Nanoparticles Loaded with Geraniin from Phyllanthus Watsonii Extract as a Phytochemical Delivery Model

The study outlined a standardized double emulsion method for simple poly(ethylene glycol)-block-poly(lactic-co-glycolic acid) (PEG-b-PLGA) nanoparticle (NP) synthesis. The PEG-b-PLGA NP was also used for entrapment of geraniin as a simple model system for phytochemical delivery. PEG-b-PLGA NPs were prepared using the double emulsion method. The yields and particle sizes of PEG-b-PLGA NPs obtained with and without encapsulation of geraniin were 57.6% and 134.20 ± 1.45 nm and 66.7% and 102.70 ± 12.36 nm, respectively. High-performance liquid chromatography of geraniin that was extracted from Phyllanthus watsonii was detected at 64 min. Geraniin burst release began at 40 min and fully released at 3 h. PEG-b-PLGA NP was non-cytotoxic, while cytotoxicity of geraniin was dose dependant towards normal human epithelial colon cells, CCD 841 CoN cells.

Identification of Potential Inhibitors for Targets Involved in Dengue Fever

Lethality due to dengue infection is a global threat. Nearly 400 million people are affected every year, which approximately costs 500 million dollars for surveillance and vector control itself. Many investigations on the structure-function relationship of proteins expressed by the dengue virus are being made for more than a decade and had come up with many reports on small molecule drug discovery. In this review, we present a detailed note on viral proteins and their functions as well as the inhibitors discovered/designed so far using experimental and computational methods. Further, the phytoconstituents from medicinal plants, specifically the extract of the papaya leaves, neem and bael, which combat dengue infection via dengue protease, helicase, methyl transferase and polymerase are summarized.

The Geraniin-Rich Extract from Reunion Island Endemic Medicinal Plant Phyllanthus phillyreifolius Inhibits Zika and Dengue Virus Infection at Non-Toxic Effect Doses in Zebrafish

The mosquito-borne viruses dengue (DENV) and Zika (ZIKV) viruses are two medically important pathogens in tropical and subtropical regions of the world. There is an urgent need of therapeutics against DENV and ZIKV, and medicinal plants are considered as a promising source of antiviral bioactive metabolites. In the present study, we evaluated the ability of Phyllanthus phillyreifolius, an endemic medicinal plant from Reunion Island, to prevent DENV and ZIKV infection in human cells. At non-cytotoxic concentration in vitro, incubation of infected A549 cells with a P. phillyreifolius extract or its major active phytochemical geraniin resulted in a dramatic reduction of virus progeny production for ZIKV as well as four serotypes of DENV. Virological assays showed that P. phillyreifolius extract-mediated virus inhibition relates to a blockade in internalization of virus particles into the host cell. Infectivity studies on ZIKV showed that both P. phillyreifolius and geraniin cause a loss of infectivity of the viral particles. Using a zebrafish model, we demonstrated that administration of P. phillyreifolius and geraniin has no effect on zebrafish locomotor activity while no morbidity nor mortality was observed up to 5 days post-inoculation. Thus, P. phillyreifolius could act as an important source of plant metabolite geraniin which is a promising antiviral compound in the fight against DENV and ZIKV.

Discovery of Dengue Virus Inhibitors

To date, there is still no approved anti-dengue agent to treat dengue infection in the market. Although the only licensed dengue vaccine, Dengvaxia is available, its protective efficacy against serotypes 1 and 2 of dengue virus was reported to be lower than serotypes 3 and 4. Moreover, according to WHO, the risk of being hospitalized and having severe dengue increased in seronegative individuals after they received Dengvaxia vaccination. Nevertheless, various studies had been carried out in search of dengue virus inhibitors. These studies focused on the structural (C, prM, E) and non-structural proteins (NS1, NS2A, NS2B, NS3, NS4A, NS4B and NS5) of dengue virus as well as host factors as drug targets. Hence, this article provides an overall up-to-date review of the discovery of dengue virus inhibitors that are only targeting the structural and non-structural viral proteins as drug targets.

Antiviral activity of betacyanins from red pitahaya (Hylocereus polyrhizus) and red spinach (Amaranthus dubius) against dengue virus type 2 (GenBank accession no. MH488959)

This study investigated the antiviral activity of betacyanins from red pitahaya (Hylocereus polyrhizus) and red spinach (Amaranthus dubius) against dengue virus type 2 (DENV-2). The pulp of red pitahaya and the leaves of red spinach were extracted using methanol followed by sub-fractionation and Amberlite XAD16N column chromatography to obtain betacyanin fractions. The half maximum cytotoxicity concentration for betacyanin fractions from red pitahaya and red spinach on Vero cells were 4.346 and 2.287 mg ml-1, respectively. The half-maximal inhibitory concentration (IC50) of betacyanin fraction from red pitahaya was 125.8 μg ml-1 with selectivity index (SI) of 5.8. For betacyanin fraction from red spinach, the IC50 value was 14.62 µg ml-1 with SI of 28.51. Using the maximum non-toxic betacyanin concentration, direct virucidal effect against DENV-2 was obtained from betacyanin fraction from red pitahaya (IC50 of 126.70 μg ml-1; 95.0 % virus inhibition) and red spinach (IC50 value of 106.80 μg ml-1; 65.9 % of virus inhibition). Betacyanin fractions from red pitahaya and red spinach inhibited DENV-2 in vitro.

Antiviral activity of ethanol extract of Geranii Herba and its components against influenza viruses via neuraminidase inhibition

Influenza viruses are a serious threat to human health, causing numerous deaths and pandemics worldwide. To date, neuraminidase (NA) inhibitors have primarily been used to treat influenza. However, there is a growing need for novel NA inhibitors owing to the emergence of resistant viruses. Geranii Herba (Geranium thunbergii Siebold et Zuccarini), which is edible, has long been used in a variety of disease treatments in Asia. Although recent studies have reported its various pharmacological activities, the effect of Geranii Herba and its components on influenza viruses has not yet been reported. In this study, Geranii Herba ethanol extract (GHE) and its component geraniin showed high antiviral activity against influenza A strain as well as influenza B strain, against which oseltamivir has less efficacy than influenza A strain, by inhibiting NA activity following viral infection in Madin–Darby canine kidney cells. Thus, GHE and its components may be useful for the development of anti-influenza drugs.

In Vitro Antiviral Activity Against Zika Virus From a Natural Product of the Brazilian Brown Seaweed Dictyota menstrualis

Natural products isolated from seaweeds have shown great antiviral potential against numerous viruses such as human type 1 herpes, human immunodeficiency virus, and dengue. Diterpenes produced by the brown seaweeds Dictyota and Canistrocarpus, in particular, have shown antiviral or virucidal activity. Recently, the Zika virus (ZIKV) has become a major public health concern due to its widespread dissemination throughout the Americas. Since no vaccines are available, and no drugs have effectively treated recent cases of infection, our group evaluated products from Dictyota menstrualis for their antiviral potential, alone and in combination with Ribavirin. We first evaluated the compounds’ cytotoxicity at high concentrations, and then evaluated the inhibition of ZIKV replication by crude extracts and acetylated crude extracts and their fractions at 20 μg/mL. The F-6 and FAc-2 fractions, rich in cyclic diterpenes with aldehyde groupings, inhibited ZIKV replication by >74%, with inhibition behaving in a dose-dependent manner and the 50% effective concentration (EC50) values of 2.80 (F-6) and 0.81 (FAc-2) μg/mL. Regarding the mechanism of action, FAc-2 had strong virucidal potential, and F-6 inhibited viral adsorption. Associating FAc-2 with Ribavirin at suboptimal dosages produced a strong synergistic effect that completely inhibited viral replication. Our results indicate that these natural products have excellent inhibitory potential against ZIKV replication and may be promising for developing affective therapies.

Recent update on anti-dengue drug discovery

Dengue is the most important arthropod-borne viral disease of humans, with more than half of the global population living in at-risk areas. Despite the negative impact on public health, there are no antiviral therapies available, and the only licensed vaccine, Dengvaxia^®, has been contraindicated in children below nine years of age. In an effort to combat dengue, several small molecules have entered into human clinical trials. Here, we review anti-DENV molecules and their drug targets that have been published within the past five years (2014-2018). Further, we discuss their probable mechanisms of action and describe a role for classes of clinically approved drugs and also an unclassified class of anti-DENV agents. This review aims to enhance our understanding of novel agents and their cognate targets in furthering innovations in the use of small molecules for dengue drug therapies.

Efficacy of geraniin on dengue virus type-2 infected BALB/c mice

BACKGROUND

Dengue continues to be a major international public health concern. Despite that, there is no clinically approved antiviral for treatment of dengue virus (DENV) infections. In this study, geraniin extracted from the rind of Nephelium lappaceum was shown to inhibit the replication of DENV-2 in both in vitro and in vivo experiments.

METHODS

The effect of geraniin on DENV-2 RNA synthesis in infected Vero cells was tested using quantitative RT-PCR. The in vivo efficacy of geraniin in inhibiting DENV-2 infection was then tested using BALB/c mice with geraniin administered at three different times. The differences in spleen to body weight ratio, DENV-2 RNA load and liver damage between the three treatment groups as compared to DENV-2 infected mice without geraniin administration were determined on day eight post-infection.

RESULTS

Quantitative RT-PCR confirmed the decrease in viral RNA synthesis of infected Vero cells when treated with geraniin. Geraniin seemed to provide a protective effect on infected BALB/c mice liver when given at 24 h pre- and 24 h post-infection as liver damage was observed to be very mild even though a significant reduction of DENV-2 RNA load in serum was not observed in these two treatment groups. However, when administered at 72 h post-infection, severe liver damage in the form of necrosis and haemorrhage had prevailed despite a substantial reduction of DENV-2 RNA load in serum.

CONCLUSIONS

Geraniin was found to be effective in reducing DENV-2 RNA load when administered at 72 h post-infection while earlier administration could prevent severe liver damage caused by DENV-2 infection. These results provide evidence that geraniin is a potential candidate for the development of anti-dengue drug.

Permeability of the ellagitannin geraniin and its metabolites in a human colon adenocarcinoma Caco-2 cell culture model

Geraniin and its metabolites, found in many edibles, were classified as per the BCS. This finding can be used to predict its' in vivo oral absorption.