Plant materials have been used for medicinal purposes since ancient times, keeping natural sources as the primary source of all drugs until about a century ago (Joo, 2014; Pan et al., 2014). Environment and nature have offered many remedies to treat human ailments. Almost half a million plant species are currently used as medicinal plants worldwide (Mukhuddin et al., 2024). As of the latest available data from the World Health Organization, 70-80% of people in South Asian countries use various plants as their primary source of medicine to cure different diseases, including cough, cold, and fever. Traditional medicine is practiced mainly in India, China, Japan, Pakistan, Sri Lanka, and Thailand (Musa et al., 2023). Bangladesh has been profusely prosperous in medicinal plants due to favorable weather and fertile land (Mukul et al., 2007; Prodhan et al., 2017). Bangladeshi forests, jungles, hills, and flatlands possess at least five thousand herbs, shrubs, trees, and aromatic and aquatic plants (M. Rahman & Fakir, 2015). Not surprisingly, a district in the southern part of Bangladesh named Gopalganj is also considered an extra habitat for numerous medicinal plants (Siddique et al., 2021). The socio-economic conditions in Gopalganj significantly impact the health of its population. Despite a steady increase in healthcare facilities, the overall situation remains challenging. Only 30% of the population has access to primary healthcare services. Approximately 20% of the population can avail themselves of Western medicines, while the majority, about 75-80% of rural residents, still rely on traditional ethnomedicine practitioners for health care worldwide (Shahen et al., 2019; Shah et al., 2013).

These practitioners are crucial in providing primary healthcare services to rural communities. Besides, they have been used as therapeutic agents and raw materials for modern medicine. Traditional medical practitioners, not only in Gopalganj but also in the Indian subcontinent, have long utilized medicinal plants like Vitex negundo, Moringa oleifera, Madhuca longifolia, Achyranthes aspera, and Aloe indica for treating various diseases. Many of the population of the world still heavily rely on herbal medicines to keep themselves healthy and disease-free (Alamgir et al., 2018; Gurib-Fakim, 2006; Mohd et al., 2012; Parveen et al., 2020). Medicinal plants are rich in antioxidants and secondary metabolites that protect against diseases linked to free radicals (Lawal et al., 2017; Savithramma et al., 2011). For instance, Ocimum sanctum L. has been finely recorded for its therapeutic potential and described as an antiasthmatic and antiseptic drug (Dubey & Pandey, 2018). Recent observations by different health authorities have demonstrated that plant medicines have been used progressively by less developed areas as they are the only means of keeping healthy there, and also have been used by developed countries as they produce fewer side effects with a greater probability of getting well from various diseases (Salmerón-Manzano & Manzano-Agugliaro, 2020). 

In this survey, we aimed to demonstrate the relationship between the availability of valuable medicinal plant in the local area of Gopalganj and their usage method. We also demonstrated how an underdeveloped area of Bangladesh has survived cough, cold, and fever for thousands of years, almost only through traditional medicines. As different plant medicines are ubiquitous in the Gopalganj district, so biotechnologists have an excellent opportunity to develop a multipurpose variety of plants through various genetic manipulations. However, there remains a limited understanding of their mechanisms of action, and integrating these traditional practices with modern medicine has been a challenge (Rahman et al., 2013; Matos et al., 2021; Rony et al., 2019).

Study area
Gopalganj is a district in the Dhaka Division of Bangladesh, with 1,172,415 inhabitants and a surface area of 1,490 km2. It is located on the bank of the Madhumati River. The maximum and minimum average temperature in Gopalganj district varies from 8.6°C to 23.3°C. The study covers forty villages (Parulia, Kumaria, Sonadanga, Krisnopur, Laxmipur, Digharkul, Shibpur, Sajail, Kusumdia, Haridashpur, Majra Bathoydupa, Ratkandi, Haturia, Vadulia, Bairpara, Chotokharkandi, Mahanag, Teguria, Bethuri, Rahimdia, Narail, Dhirail, Puisur, Hatisur, Dlnia, Bagajuru, Gopinathpur, Vabanipur, Gonapara, Haridaspur, Paranpur, Fakirkandi, Manikharpur, Tetigati, Vojargati, Vatiapara, Nijamkandi and Kati) under the Madhumati floodplain in Gopalganj Sadar and Kashiani upazila under the Gopalganj district. 

Methodology
In this survey-based study, traditional medicinal plant data were collected from local people and kavirajes across the Gpalganj sadar upazila and Kashiani upazila of Gopalganj district through interviews and questionnaire fill-out between during 24th May to 7th July 2022. The questionnaire included:

• Questions addressing the place of the interview.

• Interviewees characteristics.

• Plants local name.

• The indications of local use.

• The used parts.

• The methods of use.

• The season of occurrence.

• The types of plants.

Secondary data and information were collected by searching from PubMed, Science Direct, Research Gate, Google Scholar, Google, CD-ROM, and previous research and survey reports. MS-Excel is used to process all collected information by microcomputer. Responses to the completed questionnaires were numerically coded and analyzed using a Microsoft Excel sheet. Moreover, descriptive statistics such as frequency and percentage distribution were used to analyze data, and graphs and tables were used to interpret the findings.

The investigation, and writing-original draft, were prepared by I.H.S.; modifying draft preparation, editing, data creation, and figures were prepared by T.A.E. and A.K.B.; Writing review, Editing, Visualization, and References were prepared by S.K.B. All authors have read and agreed to the published version of the manuscript.

We want to express our sincere gratitude to the Department of Biotechnology and Genetic Engineering, Bangabandhu Sheikh Mujibur Rahman Science and Technology University, Gopalganj, which has been dedicated to providing technological support.

The authors declare no conflicts of interest.

This study area has a vast diversity of medicinal plants and traditional medicinal knowledge (Kumari & Kumari; Mondol et al., 2019). In this investigation, the indigenous knowledge of 28 plant species belonging to 22 families was collected with scientific names, family names, local names, and modes of use used for treating cough ailments by Kavirajes and local peoples. These species are Acacia nilotica, Achyranthes aspera, Acorus calamus L., Adhato vassica, Allium cepa, Asparagus racemosus, Adhatoda zeylanica, Acalypha indica, Boerhaavia diffusa L., Cajanus cajan L., Calotropis procera, Citrullus lanatus, Datura metel L., Dillenia indica L., Ficus hispida, Hibiscus rosa-sinensis L., Kalanchoe pinnata Ocimum sanctum L., Phyllanthus emblica L.,  Piper longum L., Piper nigrum L., Plumbago indica L., Terminalia chebula, Tinospora cordifolia, Tylophora indica, Vitex negundo L., Withania somnifera and Zingiber officinale. Among the selected species of medicinal plants, the maximum contribution was recorded for herbs species (36%), followed by shrubs (25%), trees (21%), and climbers (18%) (Fig. 1).

Fig. 1: Habit pattern of medicinal plants used in cough, cold, and fever.

Moreover, among the selected species, usable plant parts used was maximum for the whole plant with nine species (28.12%), followed by fruit with six species (18.75%), leaf with five species (15.62), root with three species (9.37%), seeds with two species (6.25%), seeds with two species (6.25%), rhizome with two species (6.25%), bark with one species (3.12%), bulb with one species (3.12%), stem with one species (3.12%) and flower with one species (3.12%) (Fig. 2). 

Fig. 2: Usable plant part of medicinal plants used in cough, cold, and fever.

Herbs are used a maximum of 75 % in the treatment of cold and a minimum of 36 % in case of cough The highest number of whole plants was used in case of cough and the lowest number was used in cold treatment. We also collected eight medicinal plants from the study area with their scientific name, family names, local names, and modes of use that are used against the cold. These plants are Acacia nilotica, Allium cepa, Brassica nigra, Nigella sativa  L., Ocimum sanctum L., Piper longum L., Tagetes erecta L. and Zingiber officinale. Among the selected species of medicinal plants, the maximum contribution was recorded for herb species (75%) followed by trees (25%) (Fig. 1). Besides, among the selected species, usable plant parts used for the treatment were the leaf with two species (20%), fruit with two species (20%),  seeds with two species (20%), whole plant with one species (10%), root with one species (10%), rhizome with one species (10%) and bulb with one species(10%) (Fig. 2).

Table 1: Medicinal plants, Local name, and their parts used for treating cough, cold, and fever ailments.