As the ongoing COVID 19 pandemics has become a global health crisis and it mainly affects respiratory tract. An effort for presenting the traditional expectorents of the herbal medicine gains its attention, which is promising for the world population from the plant genetic resources to reduce the pressure on pharmacy for medicine. Herbal expectorants are proved to be environmentally safe and are available in around any habitats. Forty-eight species of plants used traditionally as expectorants from six continents are included in the present study. Plant parts used, its dosage forms, bioactive compounds having expectorant activities are evaluated in the study. Abies webbiana Lindl. belongs to gymnosperm, Adiantumcapillus-veneries L. is a pteridophyte and 42 others are flowering plants. These plants were distributed and used as herbal expectorants in different continents of the world except Antartica. Forty-two species studied are distributed in Asia, thirteen species in Europe, six species from South America, five species in Africa and three species each in Australia and North America. Distribution pattern with respect to different continent is considered, which is an added attraction. During this dreadful situation people can rely on herbal expectorants to subside respiratory infections and increase immunity.
The initial symptoms of COVID-19 patients include were fever, myalgia, sore throat and dry cough which are common to any acute respiratory virus infection. Pneumonia were consistent with the manifestation of lower respiratory tract infections. By contrast, upper respiratory tract symptoms were less common in these patients. Non-specific symptoms included dizziness, diarrhoea, vomiting, headache, and generalised weakness [1-20].
Chloroquine, a widely used anti-malarial and autoimmune disease drug, was reported as a potential broad-spectrum antiviral drug [2-38]. Remdesivir is an adenosine analogue, which incorporates into nascent viral RNA chains and results in pre-mature termination [3-42]. It was repoted that remdesivir and chloroquine are highly effective in the control of 2019-nCoV infection in vitro [4-44]. Azithromycin added to hydroxychloroquine was significantly more efficient for virus elimination [5-48]. Development of its preventive and treatment is still an ongoing process by scientists from all over the world. It is in this contest an effort for presenting the traditional expectorants of the herbal medicine gains its attention, which is promising for the world population when enough quantity of medicine is not available. When world is in the hands of terrifying infection, people with mild symptoms can exist with herbal solutions.
Forty-eight species of plants used traditionally as expectorants in different parts of the world are critically avaluated and presented in Table 1. Among these species Abies webbiana Lindl. belongs to gymnosperm, Adiantum capillus-veneries L. is a pteridophyte and rest other species are flowering plants that include six monocot speceis belong to four families and forty species are dicotyledons from twenty-six families. These plants are distributed and used as herbal expectorants in different continents of the world except Antartica. Forty-two species studied are distributed in Asia, thirteen species in Europe, six species from South America, five species in Africa and three species each in Australia and North America. Eucalyptusglobulus Labill. is widely distributed in all the six continents either by natural occurance or by way of cultivation. Marrubium vulgare Linn. and Origanum majorana Linn. are scattered in three continents; Africa, Europe and Asia, while Borago officinalis Linn., is distributed in South America, Europe and Asia. Other species are limited to one or two continent in distribution and used as herbal expectorants.
Table 1:List of plant species used as expectorants from different parts of the world and key source of information.
Herbal drugs in crude form or in polyherbal formulations for the treatment of cough are better alternatives of modern cough drugs [6-50]. Decoctions or infusions of different parts of the plants studied are used individually or in combinations to cure cough, sore throat, bronchitis, asthma and other respiratory tract problems. In Dorema ammoniacum, Liquidambar orientalis and Styrax benzoin, stem exudates are used as expectorant. Researches on herbal medicines have reported that bio active components like saponin, alkaloids, flavonoids, terpinoids and phenolic compounds are used in the treatment of cough . Terpinoids and flavonoids are found to be major bio active compounds having expectorant action in the selected plant species. Phenols, alkaloids and saponins are also components of these plants involved in cough remedies. Limonene an expectorant is a monoterpene present in three plants Carum carvi, Melaleuca leucadendron and Zingiber officinale. Flavanoid luteolin is a cough suppresser isolated from Anisochilus carnosus, Ficus carica and Mucuna monosperma [51-66]. Cressa cretica, Eucalyptus globulus and Ficus carica contain flavonoid quercetin which is an expectorant theraputic. Flavonoid rutin has an expectorant activity obtained from Brunella vulgaris, Tussilago farfara and Viola tricolor. Origanum majorana and Thymus serpyllum yield natural terpinoid thymol with expectorant property. Bio active components of the plants included in the present study shows there relevance to be used as expectorant in folk medicines [65-72].
Based on the present understanding of novel coronavirus
pathogenesis and symptoms known so far, an attempt has been
made to enunciate the various medicinal herbs from the plant
genetic resources in different continents of earth [73-82]. The
plants and its parts, which are used as its decoctions and infusions
and their combinations could be done as a treatment benefit for
COVID-19 patients and those with seasonal flu and health issues.
This may also increase immunity of the patients and provide
resistance and safety of them against the viral infection [83-96].
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Professor, Chief Doctor, Director of Department of Pediatric Surgery, Associate Director of Department of Surgery, Doctoral Supervisor Tongji hospital, Tongji medical college, Huazhong University of Science and Technology