Herbal Drugs and Medicinal Plants in Controlling and Treatment of Diseases Caused by Dengue Virus (DEN-1 & 2): Ethnopharmacology, Chemistry, Clinical and Preclinical Studies

Dengue fever (DF) occurs worldwide and is a global health threat due to high mortality and morbidity, especially in tropical and subtropical regions. The World Health Organization is very concerned about this disease as it affects a large part of the population. About 2.5 billion people are at risk of contracting the dengue virus (DENV). DENV affects over 100 countries, including Europe and the US. Dengue fever is the most common viral disease. There are four different DENV serotypes (DENV-1 to DENV-4), but DENV-5 serotypes have now also been found. DENV is transmitted from person to person by the bites of infected female Aedes aegypti and Aedes albopictus mosquitoes. Unfortunately, there is no effective approved treatment for dengue and no vaccine to treat the viral infection. Researchers have turned to medicinal plants in search of natural compounds that can be used as a treatment for dengue fever. Therefore, focus is on medicinal plant extracts, which may be more effective, safer, and less toxic than synthetic drugs. Current research indicates that natural foods represent a rich potential source of novel compounds against dengue fever. From 1997 to 2012, 31 species from 24 families such as Cryptonemia crenulata, Flagellaria indica, Hippophae rhamnoides, Cladosiphon okamuranus, Castanospermum austral, Quercus lusitanica, Rhizo, Euphorbia hirta, Kaempferia parviflora, Leucaena leucocephala, Chondrus crispus, Gigartinaceae Lambda, Andrographis paniculata, Azadirachta indica, Mimosa scabrella, Momordica charantia, Andropogon citratus, Carica papaya, Cladogynos orientalis, Curcuma longa, Cymbopogon citratus, Lippia alba, Meristiella gelidium, Piper retrofractum, Psidium guajava, Ocimum Saintum, Phyllanthus urinaria, known to be active against dengue fever, were described in 61 studies. From these 11 species, about ten phytochemicals have been isolated, among which there are compounds Andrographolide, 4hydroxypanduratin A, panduratin A, Turmerone, Castanospermine, Lambda, carrageenans, Galactomanan, Kappa carrageenan, and so on that could potentially be used to treat dengue fever. Flaviviruses were found to be resistant to crude extracts and essential oils derived from 31 different species.