Dengue fever, a mosquito-borne disease caused by the dengue virus, is a major public health concern worldwide. With no specific treatment or widely available vaccine, prevention is key. This is where chemistry steps in, offering solutions to protect against dengue.

Dengue fever causes mortality and morbidity around the world, specifically in the Tropics and subtropic regions, which has been of major concern to governments and the World Health Organization (WHO). As a consequence, the search for new anti-dengue agents from medicinal plants has assumed more urgency than in the past. Medicinal plants have been used widely to treat a variety of vector ailments such as malaria. The demand for plant-based medicines is growing as they are generally considered to be safer, non-toxic and less harmful than synthetic drugs. This article reviews potential anti-dengue activities from plants distributed around the world. Sixty-nine studies from 1997 to 2012 describe 31 different species from 24 families that are known for their anti-dengue activities. About ten phytochemicals have been isolated from 11 species, among which are compounds with the potential for development of dengue treatment. Crude extracts and essential oils obtained from 31 species showed a broad activity against Flavivirus. Current studies show that natural products represent a rich potential source of new anti-dengue compounds. Further ethnobotanical surveys and laboratory investigations are needed established the potential of identified species in contributing to dengue control.

Dengue fever (DF) has been classified as a tropical disease that is caused by the dengue virus which is transmitted by the Aedes aegypti mosquito. Dengue is a typical example of an infectious disease in which the first symptoms occur four to six days after the insect's bite, but may develop even after two weeks after the event. Symptoms of DF includes high fever, severe headache, extreme joint and muscle aches, fatigue nausea, vomiting, skin rash, and mild nose or gum bleeding. DF has been recognized as one of the greatest global health problems due to the high number of people that are at risk of infection. This chapter provides informative overview of dengue infection that will give proper understanding about its transmission, prevention, treatment, and drug discovery opportunities from medicinal plants and phytochemicals. In the process of review, authors found that some plants from the following families could be vital sources of anti-dengue phytochemicals: Chordariaceae, Lamiaceae, Saururaceae, Rutaceae, Myrtaceae, Malvaceae, Meliaceae, Aristolochiaceae, Monotropaceae, Piperaceae, Caricaceae, Cucurbitacea, Acanthaceae, Euphorbiaceae, Menispermaceae, and Labiatae. Other plant families can also be found in the chapter.

Dengue fever is caused by the mosquito-borne dengue virus (DENV) serotypes 1-4, and is the most common arboviral infection of humans in subtropical and tropical regions of the world. Dengue virus infections can present with a spacious range of clinical signs, from a mild feverish illness to a life-threatening shock syndrome. Till now, there is no approved vaccine or drug against this virus. Therefore, there is an urgent need of development of alternative solutions for dengue. Several plant species have been reported with anti-dengue activity. Many herbal/natural drugs, most of which are commonly used as nutritional components, have been used as antiviral, larvicidal, mosquitocidal and mosquito repellents that may be used against dengue. The objective of this review article was to provide current approaches for the treatment and management/prevention of dengue fever by targeting viral proteins involved in replication cycle of the virus and different developmental stages of mosquito.

Dengue fever is prevalent in subtopic regions, producing mortality and morbidity worldwide, which have been of major concern to different governments and World Health Organization. The search of new anti-dengue agents from phytochemicals was assumed to be highly emergent in past. The phytochemicals have been used in wide distribution of vector ailments such as malaria. The demand of the phytochemicals is based on the medicines which are mostly considered to be safer, less harmful than synthetic drugs and nontoxic. This review mentions majorly about the phytochemicals potentially inhibiting dengue fever around the world. The phytochemicals have been isolated from different species, have potential for the treatment of dengue. Different crude extracts and essential oils obtained from different species showed a broad activity against different phytochemicals. The current studies showed that natural products represent a rich source of medicines toward the dengue fever. Furthermore, ethnobotanical surveys and laboratory investigation established identified natural plants species in the development of drug discovery to control the dengue fever.

A resurgence of dengue fever in Cuba associated with the failure of a large government program to maintain an early success in control of Aedes aegypti is reported by Gary Taubes (News & Comment, [11 July, p. 174][1]). Experts are reported to believe that effective and long-standing control might follow individual community efforts to control this mosquito vector for dengue fever. The article also reports that Aedes aegypti breeds in human-made containers. In 1991, my co-authors and I reported showing that certain commonly available marigolds, after steaming, yield a stable oil that acts as a larvicide against Aedes aegypti both in laboratory tests and in barrel tests ([1][2]). Because Aedes aegypti usually forms larvae in limited volumes of water, this finding might be worthy of investigation for control of dengue fever in Cuba. 1. [↵][3]1. M. M. Green, 2. J. M. Singer, 3. D. J. Sutherland, 4. C. R. Hibben , J. Am. Mosq. Control Assoc. 7, 282 (1991). [OpenUrl][4][PubMed][5][Web of Science][6] [1]: /lookup/doi/10.1126/science.277.5323.174 [2]: #ref-1 [3]: #xref-ref-1-1 View reference 1 in text [4]: {openurl}?query=rft.jtitle%253DJournal%2Bof%2Bthe%2BAmerican%2BMosquito%2BControl%2BAssociation%26rft.stitle%253DJ%2BAm%2BMosq%2BControl%2BAssoc%26rft.aulast%253DGreen%26rft.auinit1%253DM.%2BM.%26rft.volume%253D7%26rft.issue%253D2%26rft.spage%253D282%26rft.epage%253D286%26rft.atitle%253DLarvicidal%2Bactivity%2Bof%2BTagetes%2Bminuta%2B%2528marigold%2529%2Btoward%2BAedes%2Baegypti.%26rft_id%253Dinfo%253Apmid%252F1895085%26rft.genre%253Darticle%26rft_val_fmt%253Dinfo%253Aofi%252Ffmt%253Akev%253Amtx%253Ajournal%26ctx_ver%253DZ39.88-2004%26url_ver%253DZ39.88-2004%26url_ctx_fmt%253Dinfo%253Aofi%252Ffmt%253Akev%253Amtx%253Actx [5]: /lookup/external-ref?access_num=1895085&link_type=MED&atom=%2Fsci%2F277%2F5326%2F623.2.atom [6]: /lookup/external-ref?access_num=A1991FX04900015&link_type=ISI

Dengue is a major public health challenge worldwide, particularly in tropical areas. Nearly 390 million infections and 22,000 deaths occur every year. At present, there are no specific therapeutics available to treat dengue; however, possible treatment procedures are explained in the traditional medical systems (TMSs), such as Sri Lankan TMS, Indian Ayurvedic, Unani, and Siddha TMS. In these TMSs, medicinal plants have been used in several ways against dengue, such as virocides, larvicides, and mosquito repellents. Therefore, medicinal plants inherit biologically active compounds/lead compounds that are yet to be identified chemically and physiologically. Herein, we discuss the possible applications of crude plant extracts and isolated phytochemicals from medicinal plants such as quercetin, sulfated galactomannans, flavonoids, and glabranine in controlling dengue. Moreover, medicinal plant-based therapeutics can be safer, cost-effective, and non-toxic. Therefore, this paper reviews the medicinal plants that are used in TMSs to manage dengue, the phytochemicals they contain, and mode of action of these phytochemicals such as virocides, larvicides, and mosquito repellents.

Source Agritrop Cirad (https://agritrop.cirad.fr/615490/)

Dengue virus (DENV) serine protease enzyme, i.e. NS2B-NS3pro (non-structural protein 2B-non-structural protein 3) has been approved as prime drug target for the drug discovery against dengue infection, because of its essential role in viral replication. This study demonstrates the potential of bioflavonoids from Azadirachta indica against dengue infection using computational and experimental approach. Initially, 49 bioflavonoids reported in Azadirachta indica were collected and virtually screened on the catalytic triad of DENV protease, results in the identification of kaempferol-3-O-rutinoside (−9.555 kcal/mol), rutin (−9.324 kcal/mol), hyperoside (−7.879 kcal/mol), and epicatechin (−7.622 kcal/mol) as potent viral protease inhibitors against reference compound quercetin (−6.94 kcal/mol). Subsequently, these docked complexes were analyzed for the stability via molecular dynamics simulations and free binding energy calculations, suggested the considerable stability of selected bioflavonoids with viral protease. Additionally, density functional theory and ADMET (Absorption, Distribution, Metabolism, Excretion and Toxicity) analysis indicated the least chemical reactivity and considerable medicinal properties, respectively for the screened bioflavonoids by comparison to quercetin. Accordingly, kaempferol 3-O-β-rutinoside and epicatechin were evaluated at various concentrations for cell viability (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay) and in vitro antiviral activity (focus forming unit assay) against DENV-2 strain. The antiviral assay showed dose dependent inhibition of DENV-2 infectivity by the selected compounds while maximum 77.7% and 66.2% viral inhibition were recorded for 100 µM kaempferol 3-O-β-rutinoside and 1000 µM epicatechin, respectively without significant cell toxicity. These results suggested the potential of bioflavonoids from Azadirachta indica in the development of effective drug against dengue infection.Communicated by Ramaswamy H. Sarma

BACKGROUND: Dengue fever regardless of its serotypes has been the most prevalent arthropod-borne viral diseases among the world population. The development of a dengue vaccine is complicated by the antibody-dependent enhancement effect. Thus, the development of a plant-based antiviral preparation promises a more potential alternative in combating dengue disease. METHODS: Present studies investigated the antiviral effects of standardised methanolic extracts of Andrographis paniculata, Citrus limon, Cymbopogon citratus, Momordica charantia, Ocimum sanctum and Pelargonium citrosum on dengue virus serotype 1 (DENV-1). RESULTS: O. sanctum contained 88.6% of total flavonoids content, an amount that was the highest among all the six plants tested while the least was detected in M. charantia. In this study, the maximum non-toxic dose (MNTD) of the six medicinal plants was determined by testing the methanolic extracts against Vero E6 cells in vitro. Studies also determined that the MNTD of methanolic extract was in the decreasing order of M. charantia >C. limon >P. citrosum, O. sanctum >A. paniculata >C. citratus. Antiviral assay based on cytopathic effects (CPE) denoted by degree of inhibition upon treating DENV1-infected Vero E6 cells with MNTD of six medicinal plants showed that A. paniculata has the most antiviral inhibitory effects followed by M. charantia. These results were further verified with an in vitro inhibition assay using MTT, in which 113.0% and 98.0% of cell viability were recorded as opposed to 44.6% in DENV-1 infected cells. Although methanolic extracts of O. sanctum and C. citratus showed slight inhibition effect based on CPE, a significant inhibition was not reflected in MTT assay. Methanolic extracts of C. limon and P. citrosum did not prevent cytopathic effects or cell death from DENV-1. CONCLUSIONS: The methanol extracts of A. paniculata and M. charantia possess the ability of inhibiting the activity of DENV-1 in in vitro assays. Both of these plants are worth to be further investigated and might be advantageous as an alternative for dengue treatment.