CONSENSUS IN THE USE OF ETHNOMEDICINAL PLANTS DURING COVID-19 PANDEMIC IN AND AROUND DHAKA CITY

The present article deals with recording ethnomedicinal plants used by the people living in and around Dhaka city and also focuses on the plant species used during the pandemic to get relief from COVID-19. The information was gathered using open-ended and semi-structured questionnaires from 348 informants belonging to different classes of life. The survey has resulted in the recording of a total of 160 medicinal plant species belonging to 62 families and used for 157 ailments through 250 different formularies. Azadirachta indica A. Juss. was the most cited species in the study area. The highest factor informant consensus (FIC) was found in the Cuts and Wounds category, and Cynodon dactylon (L.) Pers. is the most cited species for this category. Acmella calva (DC.) R.K. Jansen was the culturally bound species attaining 100% Fidelity Level (FL) value. Among the ethnomedicinal plants, 40 species were found in the survey that were used by people to get relief from COVID-19. This interesting ethnomedicinal use is a new record for these 40 species. Most notable species are Ocimum tenuiflorum L., Justicia adhatoda L., Centella asiatica (L.) Urban, Citrus aurantifolia (Christm. & Panzer) Swingle, Syzygium aromaticum (L.) Merr. & L.M. Perry, Mentha arvensis L., Zingiber officinale Rosc., Camellia sinensis (L.) O. Kuntze, and Nigella sativa L. Since ancient times, these species have been very popular and used to treat several ailments. The use of these species during the pandemic is a new hope for COVID-19 management. But this is a preliminary report. Further long-term study is needed to confirm the claim of these plants’ use against COVID-19. Due to excessive use during COVID-19, these species have been scarce in the habitats in and around Dhaka city. Conservation measures should be applied to save these species from extinction.


Introduction
COVID-19, a newly emerging global pandemic, has been one of the major causes of mortality around the globe in the past few years. During this pandemic till vaccines were discovered, the scarcity of conventional modern medicines forced people to look for alternatives from nature, one of which is ethnomedicine. Ethnomedicinal plants are important natural resources that have been used by traditional healers and local people for centuries in the treatment of various diseases. For the scientific community, it serves as a gateway to identify new plant products with potential medicinal and commercial value, as well as a foundation for future investigation into modern drug development through the consensus on documented medicinal plants (Khan et al. 2014). The use of medicinal plants, though more or less common among all classes of people, is particularly relevant in urban areas, where access to quality healthcare is limited during critical times. The COVID-19 pandemic that started in 2019-20 has further highlighted the importance of natural remedies in treating this disease and others.
A good number of research works on the documentation and evaluation of ethnobotanical knowledge in Bangladesh are available. Most noteworthy works are Hassan and Khan (1986), Mia and Huq (1988), Alam (1992), Chowdhury et al. (1996), Alam et al. (1996), Uddin et al. (2001), Yusuf et al. (2002), Khan et al. (2002), Uddin et al. (2006), Yusuf et al. (2006), Uddin and Roy (2007), Uddin et al. (2008), Uddin et al. (2012), Haque et al. (2014), and Uddin and Hassan (2014). Apart from these, ethnobotanical research works in certain parts or in and around Dhaka city were done by Rahmatullah et al. (2009a), Ahmed et al. (2015), Ocvirk et al. (2013), Nusrat et al. (2015) and Uddin et al. (2019). These studies mainly focused on the ethnomedicinal, antidiabetic, and anti-coagulant properties of plant species. According to the above articles on ethnomedicine, there is no concept of the use of ethnomedicines for COVID-19 because COVID-19 is a newly borne pandemic disease spreading all over the world and it costs millions of lives globally. This disease has no proper modern treatment except vaccines. In the absence of modern treatment, the affected people looked for alternatives in nature to save themselves from this disease. In the present study, an attempt was made to record ethnomedicinal plants used to treat different diseases by the people in and around Dhaka city during the COVID-19 pandemic environment and also to focus on the plant species that were used during the pandemic to get relief from COVID-19; to identify the threats to ethnomedicinal plants and to make recommendations for conservation measures for the ethnomedicinal plants used during COVID-19.

Materials and Methods
Dhaka, the capital city of Bangladesh, is located in the Bengal Plain and has witnessed continuous expansion since gaining independence. On its' southern border, the city is bordered by the Buriganga river, while the eastern boundary is formed by the Balu and the Shitalakhya rivers. To the north lies the Tongi Canal, and to the west, the Turag and the Buriganga rivers define its limits (Banglapedia, 2014;Sayed et al., 2015). In the past, Dhaka was a part of the natural Sal (Shorea robusta C.F.Gaertn.) forest of Bhawalgarh, encompassing various water bodies. However, due to rapid urbanization and development, most of the natural vegetation and water bodies have suffered degradation (Rahman et al., 2011). At present, Dhaka lacks natural forests, but different stakeholders such as the City Corporation, RAJUK, and Public Work Department have been undertaken plantation initiatives along road dividers, footpaths, city parks, and lawns (Rahman et al., 2011).
Dhaka, the urban centre of Bangladesh, has a tropical climate known for its hot, damp, and humid conditions. It undergoes a well-defined monsoon period, with an average yearly temperature of 27.5°C and an annual precipitation of approximately 2000 mm, with more than 80% of it occurring during the monsoon season (Dewan and Yamaguchi, 2009). The city is situated on flat terrain at a low elevation near the sea, making it vulnerable to flooding during the monsoon season due to intense rainfall and cyclones (Hough, 2004).
The survey was conducted from January 2022 to January 2023 for a period of 13 months, with a total of sixteen field visits ( Table 1). The interviews were done at different times of the day and in different parts of the city using open-ended, semi-structured questionnaires (Alexiades,1996) so that different classes of people could be interviewed for the survey. A total of 348 informants were interviewed. They were mostly male, and their ages ranged from 18 to 96 years old. The education levels of the informants ranged from illiterate to M. Sc. degrees. Professionally, they were mostly rickshaw pullers, small vendors and housewives. During the field survey, information on the uses of plants to treat different diseases, the parts of plants used, and modes of preparation and administration were collected. The local names were collected with the help of local people. The ethnomedicinal plants mentioned by the dwellers in and around Dhaka city were identified by their vernacular names and physical specimens by a group of experts led by a taxonomist in the field. In case of confusion, voucher specimens were prepared following standard herbarium techniques Martin, 2010). These specimens were identified later by comparing them with various renowned works such as Prain (1903), Siddiqui et al. (2007); Ahmed et al. (2008a, b), Ahmed et al. (2009a, b, c, d), Uddin and Hassan (2016) and Uddin et al. (2021). Based on the information obtained from the people in the study area, all the reported ailments were categorized into 14 broad categories and tabulated. Several diseases were placed in one ailment category based on the body systems treated. To measure the level of consensus between the usage of plants in a definite ailment category and its users in the study area, the informant consensus factor (FIC) value was determined using the formula of Heinrich et al. (1998). To determine the most frequently used plant species for treating a particular ailment, fidelity level (FL) was determined following the formula of Friedman et al. (1986). Citation frequency (CF) values are useful to determine the most common medicinal plants in the study area. The CF values of medicinal plants were estimated using the formula of Friedman et al. (1986).

Results and Discussion
A total of 160 medicinal plant species belonging to 62 families were used by the people in and around Dhaka city for 157 ailments through 250 different formularies. This result indicates the huge diversity of medicinal plants and also shows the diversity of modes of use for different ailments. For each species, scientific name, local name, family, habitat, parts used, ailments, and modes of treatment are provided (Table 2). For each species, updated scientific name and family name is used (Powo, 2023). The ten most abundant families are Fabaceae, Asteraceae, Rutaceae, Lamiaceae, Amaranthaceae, Malvaceae, Cucurbitaceae, Moraceae, Solanaceae and Arecaceae (Table 2). The majority of medicinal plants are herbs (36%), followed by trees (30%), shrubs (21%), and climbers (13%) (Fig. 1). Leaves are the most commonly used parts, followed by fruits, seeds, stems and barks (Fig. 2). This suggests the sustainable use of natural resources in the study area. Among the 250 formularies, 81% were for internal applications, and the remaining 19% were for external applications (Table 2).
Besides, some ethnopharmacologically important plant species were determined using the informant consensus factor (FIC) parameter (Heinrich et al. 1998). The FIC value was determined to measure the agreement on each disease category among the informants living in and around Dhaka city. Fig. 4 indicates the result where FIC values ranged from 0.88 to 0.29, with the highest value (0.88) found in the Cut and Wounds category. The second-highest FIC value (0.86) was for COVID-19, followed by glandular and intestinal problems, worm and insect problems, mouth and dental problems, cardiovascular and circulatory problems, excretory problems, dermatological disorders, analgesics and antipyretics, skin and health care, digestive and liver problems, gynaecological or sexual disorders, and others. Medicinal plants that are efficient in treating a particular ailment have higher FIC values.                   The high FIC value for Cuts and Wounds showed that this ailment is possibly common in the study area and that a small number of taxa are used by a large number of people to treat this ailment. This is also applicable in case of COVID-19 category (the second highest FIC value), as the potential risk of being attacked by the Corona virus and the fear of not getting proper treatment led people to collect different species from the study area in the hope of getting relief from this disease. The higher FIC value also establishes better communication among the people in treating the particular disease. It also indicates that the species traditionally used to treat these ailments are worth searching for bioactive compounds.
The fidelity level (FL) was calculated to determine the most medicinally important plant species. Medicinal plants that are widely used for a particular disease by local people show higher FL values than those that are used to treat multiple ailments. The FL values for 17 species were calculated (Table 3), among which Acmella calva (DC.) R.K. Jansen has 100% FL, which means this species is only used for toothache treatment. There is no controversy about this use. In the case of other species, the values show less than 100% FL, which means those species have some other uses as well.  The local informants of the Purbachal area reported that, during the pandemic the distribution of Centella asiatica (L.) Urban and Andrographis paniculata (Burm.f.) Wall.ex Nees were sharply declined. Local people and as well as people from different areas were collected these species in the hope of treating the COVID-19 disease. Dream stories about the use of Centella asiatica (L.) for COVID-19 treatment were spread among the people of Purbachal and Keraniganj. According to the dream, the use of three leaves of Centella asiatica (L.) can cure COVID-19. According to the people, Centella asiatica (L.) leaves were very scarce during COVID-19, and even three leaves were sold in the market for 100 Taka. Hot, salt water with Zingiber officinale Rosc., Nigella sativa L., Ocimum tenuiflorum L., Syzygium aromaticum (L.) Merr. & L.M. Perry, raw Camellia sinensis (L.) O. Kuntze, Mentha arvensis L. and leaves, Andrographis paniculata (Burm.f.) Wall.ex Nees, were regularly used by the people who were out of vaccines. There is really no Corona Virus, as said by a good number of people, including rickshaw pullers and people from slums. They led their normal life during the pandemic situation, and they did not maintain any isolation from each other. The rate of death in slums and rickshaw pullers was very low as compared to higher society, as reported by the informants during the survey. The cited plants in the report are very preliminary in their uses against COVID-19. To validate these plants' use against COVID-19, further long-term research is necessary.
Traditionally, the oil of black cumin (Nigella sativa L.) seed is used to treat impotence by the people of Lawachara National Park (Uddin et al., 2017). Moreover, Rahmatullah et al. (2009b) reported that black cumin is taken with crushed roots of Mapania caudata Kük. to treat helminthiasis. The present survey explored a new use of this species, that is many informants in and around Dhaka regularly took black cumin to get relief from COVID-19. The roots and leaves of black pepper (Piper nigrum L.) are used to treat fever, cough, and rheumatism by the Chakma community of Bangladesh . Rahman et al. (2018) have mentioned its antimicrobial and cytotoxic activities against the germs that attack our respiratory system. The present study also found the same result where the local informants mentioned the effectiveness of the leaves and seeds of black pepper against symptoms of COVID-19. Indian pennywort (Centella asiatica (L.)) Urban has many uses, and in most cases, its whole body is taken to treat different ailments. Roy et al. (2008), Uddin et al. (2012), and Uddin and Hassan (2014) recorded that this plant's body is used to treat dysentery, diarrhoea, and other stomach-related disorders. Moreover, its leaf juice, when applied to the eyes, can help treat cataracts (Uddin et al., 2017). The present study found that people believed so much in the efficacy of Indian pennywort against COVID-19 that this species became scarce during the pandemic period due to over-exploitation. Lemon (Citrus aurantifolia (Christm. & Panzer) Swingle) is used to treat jaundice (Uddin et al., 2017) and fever (Uddin et al., 2012). The present study revealed that majority of the informants who participated in the survey took lemon juice in the belief of being relieved of COVID-19. The decoction produced from the rhizome of ginger (Zingiber officinale Rosc.) is used to treat neck pain (Uddin et al., 2017). Moreover, to treat flu and bronchitis, ginger rhizome is taken with betel leaf and also taken as a syrup by the local people of Lawachara National Park (Uddin et al., 2012). Informants of the present study linked this species with the treatment of COVID-19. Holy basil (Ocimum tenuiflorum L.) is considered the most sacred plant in Hindu scriptures. Its leaf paste is applied to reduce high blood-pressure (Uddin et al., 2017), and leaf juice is taken to treat colds and coughs (Uddin et al., 2017;Uddin and Hassan, 2014). Moreover, informants in the present study took leaf juice of this species to get relief from COVID-19 during the pandemic period. The whole plant of green chiretta (Andrographis paniculata (Burm. f.) Wall. ex Nees) is used by the people of Lawachara National Park to treat diseases like malaria , diabetes, dermatitis, and anthelmintic disorders (Uddin et al., 2017). Many informants in the present study were mentioned this plant to use in the treatment of COVID-19. The leaf juice of Malabar nuts (Justicia adhatoda L.) helps in treating colds and coughs (Uddin et al., 2017) and fever, malaria, impotence, and jaundice . The study revealed that many informants in and around Dhaka city took the leaf juice of Malabar nuts when the primary symptoms of COVID-19 developed. The leaf juice of spearmint (Mentha arvensis L.) is used to treat stomach aches (Uddin et al., 2017). This study revealed a new use of this species: many informants of Dhaka took hot leaf juice of spearmint to get relief from COVID-19. Uddin et al. (2015) recorded the use of tea (Camellia sinensis (L.) O. Kuntze) leaves in the treatment of diarrhoea. The present study also revealed that many informants drank tea regularly in the hope of being relieved from COVID-19.
The present survey recorded a number of threats to the local ethnomedicinal plants that were mentioned by the informants in and around Dhaka city and were also observed by this team of experts in the field. Most of the people mentioned rapid infrastructural development, construction works, urbanization, pollution, overexploitation, ignorance about ethnomedicinal plants, deforestation, and a lack of local medicinal plants in nurseries as the major threats. Urbanization and construction works have been observed in more or less all parts of Dhaka that were visited during this survey. In the Purbachal area green spaces are more abundant compared to other parts that were surveyed. But the deforestation of the local forest and the emigration of some of the local people from that area have resulted in the reduction of many local ethnomedicinal plants and also to the sharp decline of the ethnomedicinal knowledge bank. Many informants from the surveyed areas reaffirmed that the knowledge bank on ethnomedicines has shrunk from that of previous generations, and a lack of ethnomedicinal practices has contributed to the sharp decline of maintaining local ethnomedicinal plants in the homestead vegetation. Moreover, a lack of such plants in the local nurseries and too much dependency on aesthetic plants for home décor have also accelerated this process. Besides, people also exploit and over-exploit ethnomedicinal plants from time to time, especially when there is no alternative source of medicine during a crisis period. This was evident in the Purbachal area, where local dwellers mentioned Centella asiatica (L.) Urban and Andrographis paniculata (Burm.f.) Wall.ex Nees as plants that became scarce due to overexploitation during the COVID-19 pandemic period.
A study by Setzer et al. (2006) showed that more than 80% of rural people around the globe depend on herbal medicines. Besides, the world market for herbal medicines based on traditional knowledge was estimated at US$ 60 billion (Brevoort, 1998) more than 24 years ago. These studies prove how immensely important ethnomedicinal knowledge is! Yet its' practices and knowledge banks have been ignored by city dwellers and government and non-government authorities to a large extend. There has been no government effort so far that actually upheld or tried to uphold the local ethnomedicinal knowledge of our country. However, the practices of conserving this knowledge have only been limited to the researches of scientific communities. So, the urgent focus has to be given by all of the respective communities to conserve ethnomedicinal plants, their practices, and the people who practice this knowledge. On top of that, a number of other recommendations have been provided.
Incentives can be given to nurseries to display and sell local ethnomedicinal plants with discounts on them. Local people, especially city dwellers should be enlightened with the importance of ethnomedicinal plants. The chance of building industries on ethnomedicinal plants and their active compounds can be examined. Besides these, ethnomedicinal plants can be planted on government properties such as road dividers, road pavements, parks and lakes. A national knowledge bank on ethnomedicinal plants and the practices regarding them can be built. Compensation for the destruction of ethnomedicinal plants due to urbanization and industrialization with more secured plantations can be done. Pollution in sensitive areas such as rivers where ethnomedicinal plants are found to be growing abundantly should be stopped. Deforestation needs to be banned and a master plan regarding sustainable and urban development can be formulated.
The present work is one of the initial efforts to quantify ethnomedicinal information in Bangladesh, focusing on COVID-19 disease. This study will provide a better option for the selection of widely used medicinal plants in the search for bioactive compounds for further research. The record of 160 ethnomedicinal plant species belonging to 62 families and used for 157 ailments through 250 different formularies is an indication of the richness of ethnomedicinal plants in the study area. The highest citations of Azadirachta indica A. Juss. reaffirmed that this is one of the most important ethnomedicinal plants in Bangladesh. Cynodon dactylon (L.) Pers. is generally used for cuts and wounds treatment in all around Bangladesh and this was proved by having the highest FIC value in the present study. Acmella calva (DC.) R.K. Jansen was the culturally bound species attaining 100% Fidelity Level (FL) value. The most important finding of this present study is the record of 40 species under COVID-19 category. These species were used by local informants to get relief from COVID-19. Among these 40 species, most notable species are Holy Basil (Ocimum tenuiflorum L. ). The record of these 40 species against COVID-19 is a preliminary report. Further longterm study is needed to confirm the claim for these plants' use against COVID-19. Due to sudden excessive use during COVID-19, these species became very scarce in the habitats in and around Dhaka city. There is an urgent need to formulate suitable conservation strategies for the naturally growing ethnomedicinal plants to overcome their depletion.