Nutrient Component Analyses of Selected Wild Edible Plants From Hamirpur District of Himachal Pradesh, India: An Evaluation For Future Food

Background: Indigenous people of any particular region use various wild plants for their food, medicines, and other economic products. Many of these wild plants have been documented for their utilization as future foods and medicines based on these people's information. However, information about the nutrient components of many wild edible plants has yet to be scientically tested. Therefore, this study evaluated the nutrient components of selected wild edible plants. Methods: A total of 21 species were selected for nutrient and mineral analyses from a total of 90 wild edible plants reported during the survey of 1720 households. Based on the reported edible use, different plant parts of each species were evaluated for their carbohydrate, protein, fat, vitamin, and mineral contents. The obtained data were then analyzed using various quantitative indices to assess the selected wild edible plant's ecacy. Results: It was found that nutrient content considerably varied among all the selected species. Among the selected plant species, Digera muricata has the richest protein content, the tuber of Dioscorea sp. has plenty of carbohydrate content, and Dioscorea bulbifera has the highest fat content. Similarly, Spondias pinnata and Boerhavia diffusa were rich sources of vitamin C and vitamin E, respectively. Digera muricata was found to be promising future food based on overall nutrient composition. Conclusions: Several traditionally used wild edible plants can have surprisingly higher nutritional contents. These plants can offer a basis for developing dietary supplements and nutraceuticals on a commercial scale. Thus, scientic evaluation and validation of such underutilized plants and their products may prove an alternative future food for malnutrition people.

In developing countries, wild plants' consumption is usually restricted to local indigenous people because they cannot afford cultivated commercial fruits and vegetables [11]. In India, wild plants play a signi cant role in food and nutrient security for tribal and poor people [8,12,13]. Some wild plants have been reported to have good nutritional value than commercialized fruits and vegetables [14]. These plants' higher nutritive value imparts potentially positive effects on human health by lowering the risk of many diseases such as diabetes, cancer, and heart-related disorders [1,[15][16][17]. Therefore, these plants have gained the attention of food scientists, industrialists, farmers, and other stakeholders. The dietitians are working on a new base to develop food, medicine, and supplements for undernourished people.
Nowadays, the private sector is also coming forward to promote these underutilized plants for future food [18,19]. An inventory of wild food resources and nutrient analysis for scienti c validation can establish the substitute crops for the domestic and cultivated species, which will help select important and valuable wild plant species [20].
About 1532 edible wild food species are reported in India [21], in which over 675 species are known only from the Himalayan region [22,23]. Further, it is estimated that about 800 species are consumed as wild edible species, mainly by the tribal people. Knowledge of these plant species will help explore new possibilities in further research work in food and other purposes. They may provide employment and economic bene ts to the people of rural areas. Hence, these underutilized plants are put into use as food but now are being projected as healthy food [15,[24][25][26].
Furthermore, fruits and vegetables also contain a vast and multifaceted array of bioactive secondary compounds that promise to promote good health and protect against many diseases [13,26]. To ensure an adequate dietary intake of all essential nutrients and increase the consumption of various healthpromoting compounds, researchers have been interested in improving plants' nutritional quality concerning nutrient composition and concentration [27].
The selected study area Himachal Pradesh is endowed with various climatic conditions; therefore, different kinds of tropical, subtropical, and temperate plants reside in the proximity of this Himalayan region [7,8]. Due to the variation of climatic conditions, it has a rich diversity of wild fruits, leafy vegetables, and tubers enjoyed by the local people since time immemorial. Major economic wild plants such as Aegle marmelos, Spondias pinnata, Phyllanthus emblica, Punica granatum, Pyrus pashia, Citrus sp., Ficus sp., Amaranthus sp., Chenopodium sp., Dioscorea sp., Colocasia macrorrhiza, Colocasia indica, Colocasia esculenta, Moringa oleifera, Ceropegia sp. and Bambusa sp. are found in the study area [7,8]. However, future utilization of these wild fruit, vegetable, and tuber plants are unexplored as people are unaware of their nutritive values. Moreover, many plants face the threat of extinction due to population pressure and destruction of habitat (Aegle marmelos, Spondias pinnata, Moringa oleifera, Ceropegia, etc.). Thus, the present investigation is done on the screening and evaluating the essential underutilized plants for nutrient component analyses.
In this paper, we have evaluated the nutrient components and the role of plant foods play in human nutrition and health of 21 wild plants selected from the study area, and the following questions have found as edible, of which 21 plant species were selected for nutrient analysis based on the informant's perceptions, availability, and uses. Chemical and nutrient analyses were conducted to see the e cacy of these species based on the nutrient richness and the relative nutrient value of each selected species to determine these plant species' signi cance.

Sample collection
Field trips of 3-4 days were made in different seasons to collect the samples of screened plants used for edible purposes. The aboveground plant parts were manually hand-picked, and the underground parts were dug out using a digger and spade with assistance from the local people. The collected plant samples were kept in separate thermocol (polystyrene) boxes to retain freshness during transportation.
Then samples were brought to the laboratory for nutrient and mineral analysis.

Quantitative analysis
The relative importance of selected plant species was assessed using speci c quantitative indices were developed and employed (Table 1). Firstly, the relative nutrient content (RN ij ) of jth nutrient in ith species was calculated as the ratio of jth nutrient content in ith species to all species' total jth nutrient content. This relative content was then converted to a percentage by multiplying with 100. and four exotic). However, signi cant numbers of the recorded edible plant species were herbs, followed by trees (the most dominant life form). In contrast, other growth forms of the plant-like shrubs and creepers were sparsely distributed.
Based on 472 local informants, edible parts of these plants are eaten either in raw or cooked form by the local community. Maximum numbers of wild plants as fruits are generally eaten raw when they are ripe, and usually unripe fruits, seeds, owers, and leaves are cooked as vegetables by the local people. In the case of individual edible plants, conventional and non-conventional processing is essential to make it palatable. For example, shoots of Bamboo, Agave, and Thoar (Euphorbia royleana) plants need to be peeled, boiled, and fried before consumption, whereas some plants can be directly consumed without processing. Underground parts (tuber) of Dioscorea species require washing, slicing, and boiling in salty water for a particular time and keeping them in salty water overnight to discard the tuber's acrid content.
In addition to this, young pods of Cassia stula are used to prepare pickles and Murabba (a sweet jelly preparation). Young shoots of Euphorbia royleana are being used to prepare vegetables by local people; this is perhaps a new kind of use not reported in the literature.

Evaluation of edible plants on nutritive values
A balanced and adequate diet constitutes two components, viz. food (nutrition) and functional food. Nutritional food mainly includes proteins, carbohydrates, lipids (fat). The nutritional value is the primary concern when a crop is being considered as a food source. Due to the emphasis placed on consumers' nutritional value, a great need exists for information on crops' nutritional contents [39]. However, an ideal edible plant species should be having the following qualities: a) rich content of proteins, carbohydrates, fats, dietary ber, and minerals, b) balanced amount of nutraceutical substances, particularly vitamins C, E, and B 12, c) Substantial amount of essential macro elements such as Na, K, Ca and Mg and microelements such as Fe, Cu, Zn, Mn, Ag and Au, d) medicinal importance e) economic importance and commonly available to the local people. Based on speci c criteria like survey, availability, use, and application by the local people for food and medicine; therefore, we screened 21 plant species out of ninety for nutrient component analysis.

Carbohydrate
Similarly, the allocation of carbohydrates was calculated and presented in Figure 1. Since carbohydrates are primary energy generating (yielding) substances, they are regarded as the chief energy source to each organism.

Fat content
Fat is also the primary source of metabolic energy, which indirectly regulates the ow of materials into and out of the cell. Dietary fat serves as a carrier of vitamins, A, D, E, K, and hormones. In our study, allocation of fat of the total nutrients provides impressive results among all selected species. For example, Colocasia esculenta is rich in carbohydrates but provided the highest fat allocation, followed by Boerhavia diffusa and T. cucumerina. The least amount was recorded in the fruit of D. melanoxylon ( Figure 2). Generally, plant components, leaves, and seeds provide a rich source of fat. In our study, fat content was analyzed from leaf, and a high content was recorded, for example, C. esculenta, B. diffusa, C. giganteum, and A. viridis. Furthermore, few species were observed to have a high concentration of fat (lipid) content in the present study that can be an excellent fat source.
Generally, food plant species possess fat content ranging from 0.1% to 5% or even above. Earlier studies observed that edible plant species' fat content varies with species, parts, and area of study. For example, the fat content in Boerhavia diffusa was found to be 1.16% [43], whereas it was 0.7% in leaves of Amaranthus sp. [44]. Similarly, the fat content was reported about 1.8% [45] and 5.5-7.4% in the same species Chenopodium quinoa [46], but from different study areas. These studies altogether support the present study's ndings as the fat content of all leafy vegetables was approximately within the range recorded by earlier studies.

Protein
Dietary protein is the most critical constituent among all other nutrient components, primarily involved in the growth, maintenance, and repair of the body tissue. It regulates all the processes within the body [47]. Excess protein is used as a source of energy. Based on the allocation of total protein among selected plant species, Digera muricata is found most important edible species and is allocated with a high percentage of protein (46.52%) as of total nutrients (Carbohydrate + fat + protein) followed by A. viridis 3 (g/100 g) in Digera muricata respectively on a dry basis, which is lower than the present estimation of the same species [48,49]. Out of all selected plant species, seven (7) species showed more than 10% while four species had less than 5% protein allocation. It was further observed that more than 15% allocation of protein was recorded in all leafy vegetable plants except C. esculenta. Speci cally, one fruit plant (C. grandis) exhibited more than 15% protein allocation. Hence, those plants with a high protein percentage are presumably the most important edible species as a protein source that can be recommended to people de cient in protein nutrients. Therefore, the variation in the protein contents depends upon the season of collection, location and genetic variations of the species, etc. However, leafy vegetables' variation ranged from 0.33 to 21.79 g/100 g [50,51]. The lowest value (0.57 g/100 g) was found in the fruits of Trichosanthes cucumerina. The result of the same was con rmed and reported precisely by Badejo et al. (2016), who reported protein 0.37 to 0.51 (g/100 g on a fresh weight basis) in the same species [42]. The amino acid allocation was recorded maximum in the species like A. viridis (27.9%) followed by B. diffusa, C. grandis, M. dioica, C. dichotoma, and C. giganteum ( Figure 3).

Vitamin-C
Allocation of vitamin-C of total nutrients in the selected species re ected a contrasting range from 0.01-1.0%. S. pinnata had the highest allocation, followed by M. dioica, B. diffusa, A. viridis, and B. variegata ( Figure 4). However, 6-7 species showed an intermediate-range, but those species that showed a higher range of allocation for protein and carbohydrate had low allocation for Vitamin-C. Surprisingly, one species D. muricata with the highest allocation for protein, a substantial amount of carbohydrates, exhibited an acceptable range of vitamin-C allocation slightly lower than A. viridis (a leaf vegetable). Vitamin-C generally is a good source for immunity enhancement, protection from various diseases. Various workers [52,53] have Vitamin-E B. diffusa had the highest allocation of vitamin-E followed by C. giganteum and S. pinnata whereas it was lowest in Ceropegia sp. and C. dichotoma ( Figure 5). The remaining 18 species were found in the range of 0.001-0.009%. Important vitamin-rich plant species mentioned above can be recommended as healthy diets, especially for nutrient-de cient areas. Vitamin-E is required for skincare, hair growth and also regarded as a beauty vitamin. It is a powerful antioxidant that protects the heart, blood vessels, chest pain, high blood pressure, blocked arteries, anti-aging, cancer, and liver toxicity [55]. The range of vitamin-E content was varied from 0.05 to 16.4 mg/100 g in different species mentioned above by different workers. Hence, these plants such as Aegle marmelos, Pyrus pashia, Spondias pinnata, Boerhavia diffusa, Chenopodium giganteum, etc. can be considered the sources for vitamin E supplement for local people, if it is commercialized, rest of other people would be bene tted more.

Relative nutrient value index (RNVI)
RNVI was calculated as a summation of the proportional value of major components such as protein, carbohydrate, and fat of each species. This provided adequate information for the evaluation of a plant species. Values for RNVI varied from 7-36, in which the highest was estimated for C. esculenta (34.76) followed by A. marmelos (31.32) and D. deltoidea (30.91). Local people of the study site also informed about its e cacy for edible and medicinal purposes. Across species, ten species had RNVI value in the range of (20-30), and three species had above 30 index values ( Figure 6). Taro corm (C. esculenta) is a good source of minerals. Its starch's small granule size helps increase its nutrients' bioavailability due to the e ciency of digestion and absorption [56].

Relative functional food index (RFFI)
TRFFI was calculated in the same way that it also provides su cient information about rich food value content such as vitamin-C, E, total phenol, and phytosterol. Based on the analyzed concentration of phytosterol and phenol, it is not easy to gure out the species' quality. However, through this index, it is found that S. pinnata (34.81) had a higher or better index for functional food value, followed by Dioscorea alata (26.11), Bauhinia variegata (26.01), C. giganteum (25.44), Dioscorea pentapyhlla, (24.44) and Moringa oleifera (21.18). The remaining four species exhibited TRFFI value around 20 (Figure 7). Since functional food is the composition of phytosterol, total phenol, and vitamins, they are required for protection from harmful diseases [57,58].
Generally, phytonutrients are present in the foodstuff. They may be used as food supplements and as medicinal food. Based on a single constituent like total phenol or phytosterol, it might be challenging to evaluate the quality of species for functional food value. Hence, this index provides satisfactory results. Based on this index, S. pinnata, D. alata, D. pentaphylla, C. giganteum can be recommended as a good source for functional food development. They are known to have several bioactive properties with possible implications for human health, such as the serum cholesterol-lowering effect, that might prevent colon cancer and benign prostatic hyperplasia [59].  Figure 9). This index probably provides valuable information and evaluates mineral enrichment of the species. D. muricata with highest protein allocation and highest mineral nutrients indicates that this plant can be recommended as a good source for protein and minerals rich species. In India, malnutrition is a common problem in women, older people, and children below 12, mainly residing in remote rural areas. However, if present in the plant, these elements may be a good substitute for food and a source for those speci c elements required for curing ailments of a human and veterinary purpose. Some minerals are essential to the human body, e.g., such as calcium, potassium, magnesium, sodium, phosphorus, and chloride. These are required in a large amount while others in a small quantity, usually less than 0.01% of the total body weight [57].
Most rural people suffer from malnutrition not because of the economic status but because of the inability to utilize the available nutritious underutilized crops to meet their daily requirements. There must be a need to see the economic and nutritional impact of indigenous fresh underutilized crops for its production and consumption in rural communities to meet the nutritional demand. Therefore, it can be useful for malnutrition and food insecurity for rural peoples as rural food sources. The metabolic fate or role of each element in the plant can be characterized in relation to some basic processes such as uptake (absorption), transport within plants, concentration, metabolic process, and de ciency and toxicity.
Generally, plants absorb elements through roots from the soil and aerial parts like a leaf, also known as foliar uptake, which occurs in two-phase non-metabolic cuticle parts and metabolic transportation across

Availability of data and materials
The datasets used and/or analysed during the current study are available from the corresponding author on reasonable request.