The various uses of stinging nettles
The local community uses stinging nettle as a source of food, feed and herbal medicine while most local people also regarded it as unwanted plant. A number of recent ethnobotanical studies on uses of wild plants by local communities’ in different areas of the world showed that local people harvest and used edible wild plants for food, fence, fuel, fodder, medicine and furniture (Thapa, Dhakal and Chaudhary, 2014; Suwardi et al., 2019; Purba and Silalahi, 2021; Woldemariam, Demissew and Asfaw, 2021; Woldemedhin, Lulekal and Bekele, 2021). For example, Miskoska-milevska, Stamatoska and Jordanovska (2020) investigated the traditional uses of wild edible plants in the Republic of North Macedonia. The authors indicated varies uses of U. dioica L. for preparation of infusion (leaves, roots, shoots, and seeds), dried leaves as spic, cooked as vegetable and medicinal purposes. Alemneh (2020) reported that Urtica simensis reserved only in home gardens and most commonly used species for live fence. (Al-Fatimi (2021)indicated that the use of wild plants are linked to food shortage, nutritional values and local cultural tradition. Many ethnobotanical studies of the wild edible plants contributed immensely in saving people during famine, drought and war in different developing and developed world countries (Addis, Urga and Dikasso, 2005; Abbasi et al., 2013).
The highest use-value indices of stinging nettle plant was in North Shewa zone (UVc = 0.93), followed by Arsi zone (UVc = 0.9), and Bale zone (UVc = 0.63). Its central role in North Shewa (FL = 51.7%) and Arsi zone (FL = 50 %) is as a source of both food and fodder, where as in Bale zone (FL = 33.3%) is as a source of food only. A number of comparative studies on the use-value index of wild plants showed that stinging nettle, Urtica spp., belongs to among the top 20 species with high preference for consumption with cultural importance index ranging from 0.5–1.26 CI (Mohammed S. Ali-Shtayeh et al., 2008; González, García-Barriuso and Amich, 2010; Çakir, 2017; Yesil and Inal, 2019; Ding et al., 2021; Hassen, 2021). For example, (Hassen, 2021) reported that from a total of 66 locally available wild plants, U. simensis belongs to the top five which have high preference for consumption in North Wollo, Ethiopia. In Turkey, stinging nettle is among the 20 widely consumed with cultural importance index (1.26 CI) of 154 wild plant taxa of Iğdır Province (Çakir, 2017). Recently, Ding et al. (2021) reported that stinging nettle, Urticaceae, have the highest cultural importance value next to Rosaceae from the total of 84 species of wild edible plants used by Chenthang Sherpa People, belonging to 62 genera in 40 families. Mohammed S. Ali-Shtayeh et al. (2008) studied traditional knowledge of wild edible plants used in Palestine. Stinging nettle is one of the top 20 widely consumed and with the highest mean cultural importance values in all five areas of Palestine. This could indicate that samma can be domesticated and grown as alternative crops in the future's agriculture and broadly used in human nutrition.
Preferences for habitats to collect stinging nettles
The local people indicated that stinging nettles survive and perform well almost everywhere from marginal areas to fertile soil without any agricultural input and cultivation requirement. The results can be an indicator of the potential of stinging nettle to be integrated into the farming system, for rehabilitation of degraded lands, serve as organic compost, and enhance productivity of the area on top of their role in diversification of human diet. Studies reported that stinging nettle is mostly found in farmlands, grazing lands, roadsides, forests and home gardens, plentiful near houses and can be harvested whenever there is a need (Assefa, Haki and AddisDemoz, 2013; Alemayehu, Asfaw and Kelbessa, 2015; Kefalew, Asfaw and Kelbessa, 2015; Alemneh, 2020; Gebrezgabiher, Kalayou and Sahle, 2020). For example, (Prakash et al., 2020) studied the diversity, distribution and indigenous uses of wild edible plants used by the tribal community in Pangi valley, Chamba of Himachal Pradesh, North- Western Himalaya. The authors reported that stinging nettles, U. dioica, grows very well in shady moist, dry, degraded and rocky habitats.. Afolayan and Jimoh (2009) reported that wild plants besides the natural attributes of resistance against diseases, they are more adaptive to harsh environments and grown less intensively.
The results also provide a baseline for potential domestication action of stinging nettle to sustain their conservation and utilization. Vohland and Wydra (2011) addressed issues on the role of on-farm conservation of underutilized crops in the wake of climate change as complementary measure to ex situ.
Economic status and frequency of gathering stinging nettle
According to informants, the local people who gather and cook stinging nettle are commonly referred as the poor and they call stinging nettle crop as a poor man crop. This could indicates a needs of further policy and local level awareness creation to really value stinging nettle plants and improve their uses and enhance their conservation for sustainable utilization. Vohland and Wydra (2011) indicated that efforts to promote neglected and underutilized plants are challenged by the fact that too often these resources are wrongly perceived as being “food of the poor”. Gelmesa et al. (2010) studied shifting to alternative food source: potential to overcome Ethiopia’s’ malnutrition and poverty problems. The author reported that consumption pattern of wild plants were highly related with economic status and food shortage rather than recognizing the nutritional value of the plants. For the poorest indigenous vegetable make up an important portion of their daily dietary intake in most part of the country especially during food shortage.
A wide range of studies showed a renewed or increasing interest in consuming stinging nettle plants despite the stigma related to “a poor man crop”. For example, the tradition of eating stinging nettle has not completely disappeared, their food and nutritional role (Guil-Guerrero, Rebolloso-Fuentes and Torija Isasa, 2003; Kavalali, 2003; Sajfrtová et al., 2005; Garcia, 2006; Kukrić et al., 2012; Nencu et al., 2015; Branisa et al., 2017; Carvalho et al., 2017; Durović et al., 2018; Marchetti et al., 2018; Shonte, Duodu and de Kock, 2020; Pavković, 2021; Repajić et al., 2021; Garcìa et al., 2021) and health benefits (Gülçin et al., 2004; Kukrić et al., 2012; Upton, 2013; Ghaima, Hashim and Ali, 2013; Johnson et al., 2013; Ahmed Kk and Parsuraman, 2014; Zeković et al., 2017; Jan, zarafshan and Singh, 2017; Dhouibi et al., 2020; Moreira et al., 2020; Rawat, Bameta and Gaur, 2020; Karg et al., 2021) being reported in many recent studies worldwide.
Additionally, a number of comparative studies on the use-value index of wild plants in different areas of the world showed that stinging nettle, Urtica spp., belongs to among the top 20 most culturally important species with high preference for consumption (González, García-Barriuso and Amich, 2010; Demir, 2020; Ding et al., 2021; Hassen, 2021). However, in Ethiopia the stigma related to stinging nettle “samma” being as poor man food is one of the reason masking its cultural importance and underutilization by the community. Therefore, urgent ethnobotanical studies and subsequent conservation measures are needed to salvage this plants and the associated knowledge from further loss.
Seasonal availability of stinging nettle
Stinging nettle give new flushes of growth during dry months of December to February (winter) and shortly after small rains of March to May (Spring). Which is in agreement with the findings of Feyssa and Feyssa (2012), when there is shortage of food from farm managed crops wild edible plants become optional food and feed resources However the authors noted that weedy vegetables were available only during short rainy seasons. The availability of stinging nettle during the dry periods implies their drought resistance characteristic that puts them in a relatively better position in their contribution to the community lacking alternative vegetable sources. Hence, there exists biological security to livelihood of people in the study areas by consuming stinging nettle to cope up times of food shortage.
Studies reported the seasonal availability of wild plants, e.g. stinging nettle plants (Asfaw and Tadesse, 2001a; Wondimu, Asfaw and Kelbessa, 2006; Yesil and Inal, 2019; Alemneh, 2020; Agarwal and Chandra, 2021; Ding et al., 2021). For example, the Chenthang Sherpa people collect wild edible plants (e.g. Stinging nettle) almost throughout the year, except for January and February (Ding et al., 2021). In Batman Province-southeast Turkey, Yesil and Inal (2019) found that farm herbaceous plants are consumed only until the beginning of July, after which they dry out in the summer heat and local people shift to consuming wild plants instead. Gelmesa et al. (2010) reported that consumption of indigenous vegetables is mainly during grain shortage.
Seasonal food shortages, when household stocks were empty and the new crop were still in the field were common times to dowel on collecting and consuming of stinging nettle in the study area. These could act as a motives for local people to conserve stinging nettles and encourage their domestication. Fentahun and Hager (2009) and Addis, Urga and Dikasso (2005) indicated that the year-round availability of wild edible plants provides supplementary food and nutrition and presents an opportunity for trade if properly supported by extension services. Wild plants were mostly consumed by households when there is a collapse in the harvest of cultivated food crops because of drought (Asfaw and Tadesse, 2001; Wondimu, Asfaw and Kelbessa, 2006; Alemneh, 2020). On the other hand, utilization of wild edible plants as complementary food indicates low awareness on the use and management of wild edible plants (Feyssa, 2012).
Consumable parts and traditional manipulation practices to collect stinging nettle
Local people explained that they use young and tender shoots to prepare local sauces, roots for medicine and the whole plant for fodder. Similarly, young and tender shoots represent the consumable part of the stinging nettle plant as these have higher nutritional value compared to mature leaves (Kavalali, 2003; Ioana et al., 2013). Recent studies reported that young nettle leaves extracts are a good source of polyphenols and phytochemicals that render them with nutritional, nutraceutical and functional properties. Polyphenols content of nettle leaves showed a decreasing trend with the phenological stage, total polyphenols decreased for almost 50% by the 3rd phenological stage (Repajić et al., 2021).
A number of studies reported that young and tender nettle leaves are cooked as vegetable, boiled or added to soups and sauce, dried as spice, used to prepare infusion and decoction, and for salad (Bhat, Rubuluza and Jäger, 2002; Kavalali, 2003; Maria S. Gião et al., 2007; Moskovitz, 2009; Maanda and Bhat, 2010; González, García-Barriuso and Amich, 2010; Jimoh et al., 2010; Roberts, 2011; Adhikari, Bajracharya and Shrestha, 2016; Çakir, 2017; Yesil and Inal, 2019; Prakash et al., 2020; Demir, 2020; Hançer et al., 2020; Ding et al., 2021; Kumar, 2021).
In some recent works on young nettle leaves were used for production of functional foods e.g. nettle enriched egg pasta showed the highest levels for bioavailability of micronutrients and plant metabolites at a lower colonic fermentation time (Bonetti et al., 2016; Marchetti et al., 2018); stinging nettle extract in combination with ε-polylysine enhanced the quality, safety, and shelf life of rainbow trout fillets (Azmir et al., 2020); bread-making products enriched with nettle leaves significantly increased the level of fibers, calcium and copper, and total phenolic content, lutein and β-carotene (Maietti et al., 2021); addition of whole leaves decreased the sensory quality of the bread whereas the extract improved the sensory quality and phenolic acids, flavonoids, micro elements, and macro elements (Đurović et al., 2020); addition of freeze dried extract of nettle in chocolates resulted in chocolates with an enhanced and stable polyphenolic profile during 12 months of storage, furthermore dark chocolates enriched with nettle extracts was preferred over milk and semisweet chocolates (Belščak-Cvitanović et al., 2015).
Interestingly, covering hands with cloths and wearing plastic bags were traditional manipulations practiced by the local community to protect themselves from stinging hairs thereby avoiding stinging sensation and collect the young and tender shoots from the plant. The leaves and stems of stinging nettle plant has stinging hairs called trichomes (Fig. 5). The trichomes contain chemicals such as histamine, 5- hydroxytryptamine and acetylcholine and when touched by humans and other animals it produces a stinging sensation (Bisht, Bhandari and Bisht, 2012; Mithril and Dragsted, 2012). The root, however, lacks stingers (Upton, 2013). Therefore, hand gloves and leg protection should be used to avoid the stings when harvesting the leaves (DiTomaso and Healy, 2007). The irritating contents of the stinging hairs are dissipated upon drying (Upton, 2013), blanching and cooking of the leaves (Hughes et al., 1980; Rutto et al., 2013).
Traditional methods of preparing stinging nettle for human consumption
Processing of stinging nettle plants will add value to their palatability and add charisma to the consumers. This could enable the local people to add value and support their livelihoods better than the way they use them traditionally. Stinging nettle leaves based dishes are used in the diet of many countries, particularly among low socioeconomic populations. In the study areas, a sauce is prepared from young nettle leaves and barley powder and served with injera (Table 7). As an example, nettle soup or potherb in Nepal (Adhikari, Bajracharya and Shrestha, 2016), and nettle leaves added to soups or stews in Nordic countries (e.g. Denmark, Finland, Iceland, Norway and Sweden) (Mithril and Dragsted, 2012). In the areas around the Black sea, nettles are traditional foods consumed for health purposes. It is used in the form of a sour soup in Romania, as a nettle walnut sauce in Georgia and as a herb in Ukraine (Danesi et al., 2013). Maanda and Bhat (2010) reported that stinging nettle has a flavour similar to spinach when cooked, and it is used as a side dish to flavour the meal or used to add a bitter taste to meals. Infusion and decoction made from nettle leaves leaves and leaf powder is the most traditionally used form of drinks in Portugal (Maria S Gião et al., 2007).
Furthermore, wide range of recent studies reported the traditional cooking methods of stinging nettle leaves for human consumption. For example, the leaves and the aerial parts of stinging nettle: fresh leaves cooked as vegetable or dried leaves added to soup, especially in winter (Demir, 2020); leaves are used to prepare saag for remedy to Anthelmintic, antiseptic, dandruff, gout, nephritis sprain (Kumar, 2021); decoction and infusion (Maria S. Gião et al., 2007; González, García-Barriuso and Amich, 2010; Shonte, 2017); first boiled and then fried with onions (Yesil and Inal, 2019), frequently used as green vegetable (Prakash et al., 2020); Sauteed in oil, added to pastry, fried with egg, boiled as salad and tea (Hançer et al., 2020); eaten raw, cooked with bulgur in Iğdır Province, Turkey (Çakir, 2017); roasted and then cooked, and boiled with oil and salt Vegetable (Ding et al., 2021). Local people have good knowledge of stinging nettles, including their time of availability, processing, and cooking method as well about their traditional medicinal value. The findings from the current and previous studies stinging nettle plant indicates its potential for domestication, value addition and processing for food and nutritional security and wellbeing of the consumers.
A number of recent studies attested the importance of stinging nettle plants for biological security of food source (González, García-Barriuso and Amich, 2010; Ranjan, Jamir and Ozukum, 2013; Çakir, 2017; Suwardi et al., 2019; Yesil and Inal, 2019; Miskoska-milevska, Stamatoska and Jordanovska, 2020; Prakash et al., 2020; Alemneh, 2020; Demir, 2020; Hançer et al., 2020; Agarwal and Chandra, 2021; Al-fatimi, 2021; Katrahalli and Siddeshwari, 2021; Kumar, 2021; Purba and Silalahi, 2021; Woldemariam, Demissew and Asfaw, 2021; Woldemedhin, Lulekal and Bekele, 2021; Ding et al., 2021; Golait, Auti and Laware, 2021; Hassen, 2021). Earlier studies support the present findings in the existence of high potential of stinging nettle plant to food security (Mohammed S Ali-Shtayeh et al., 2008; González, García-Barriuso and Amich, 2010; Çakir, 2017; Yesil and Inal, 2019; Ding et al., 2021; Hassen, 2021).
Analysis of Gender to collect and prepare stinging nettle
Although there were still prevailing attitudes in the community in favour of more responsibility (93.25%) on women and girls. Stinging nettle shrubby growth nature and wide availability near homesteads could have made the harvesting and collection process easier for women. Earlier studies support the present findings that stinging nettle plant predominantly leaves and young shoot parts collected and traditionally cooked by women and children (Abdulkadir and Kusolwa, 2020). In contrast, most species of tall and tree wild edible plants were predominately collected by young males especially by shepherds whereas females take full responsibility of cooking and serving the food to the family members (Alemneh, 2020). The authors’ reason out that males might have better ability to climb and grip mature tallest trees than females.
People’s perception and factors limiting harvesting and consumption of stinging nettles
Although socio-cultural barrier (e.g. religion and cultural norms and values) is the major limiting factor for consumption of stinging nettles, lack of knowledge on its food and nutritional importance and its stinginess contributed much to the underutilization of the plant. A number of recent studies stressed on the need to preserve oral traditional knowledge of the local wild plants used as food and/or nutraceutical sources for human (Pardo-de-Santayana et al., 2007; Yesil and Inal, 2019; Al-fatimi, 2021; Woldemedhin, Lulekal and Bekele, 2021). (Pardo-de-Santayana et al., 2007) studied traditional knowledge of wild edible plants used in the northwest of the Iberian Peninsula, Spain and Portugal. The authors reported that wild edible plant usage appear to depend mainly on socio-cultural factors rather than biological ones such as climate or richness of the wild edible flora. Flyman and Afolayan (2006) indicated that indigenous people in remote areas are endowed with deep knowledge concerning the use of these wild species as food especially during period of drought, famine, and civil unrest.
According to the information available, stinging nettles consumption is considered as shame and insult. In normal times only women and the poorest families regularly collect and consume stinging nettles. Farmers interviewed stated that stinging nettles are not consumed except when there is a serious shortage of food. Some of the farmers when questioned obviously felt ashamed and maybe offended by outsiders asking questions about such sensitive issues as the consumption of famine food. Under such precarious situation, the indigenous knowledge associated with the plant can be lost irreversibly. It has been previously reported that efforts to promote wild edible plants are also challenged by the fact that too often these resources are wrongly perceived as being “food of the poor” (Vohland and Wydra, 2011). Stinging nettle has been used as famine food in many areas of the world, from the Great Potato Famine in Ireland, 1845/49, to famines in Scandinavia, Ethiopia, and North India. Recent studies reported that wild edible plants such as Snowdenia polystachya (Muja), Eleusine coracana (Degelie or wanga), Urtica simensis (Sama) and Medicago polymorpha (Amaqito) are consumed during normal and famine periods (Woldemedhin, Lulekal and Bekele, 2021). In rural Spain and Portugal, many wild edible plants are regarded as famine food and are no longer gathered (Pardo-de-Santayana et al., 2007).
Although stinging nettle plants often have a stigma attached to them, being regarded as poor people's food, they are increasingly popular as local food that reflects regional identity. For example, there is a traditional song by Maritu Legesse and Amharic sayings, “These Ambassels’ know the recipe, they use samma sauce on barley bread/injera”, reflecting the food value of stinging nettles by the local community of Ambassel district of Northern Ethiopia. Additionally, movements such as chefs' interest in offering new flavours and dishes can play a crucial role in boosting the social importance of such resources. For example, one of the great chefs’ of Ethiopia, Chef Johannes, demonstrated the food and nutritional value of stinging nettle “samma” together with its cultural norms and values. Therefore, the indigenous knowledge on the way local people perceive and use stinging nettles “samma” plays an important role in their conservation and as to whether a family could maintain nutritional well-being or succumb to malnourishment.