Selection of neglected and underutilized species for nutrient analysis
The criteria for selecting the species for nutrient analysis are the neglected and underutilized species sold in local markets, which could be alternative sources to commercial vegetables, fruits and spices. These have a high preference among locals and are found primarily in the wild, and most importantly, these native plants were cultivated to a minimal extent. Hence, determining the nutritional components will allow the selection of these species to form a province for initiating large-scale cultivations for sustainable development in the food sector.
Table 1: List of selected wild edible plant species based on 3 categories (Spice, Vegetable and Fruits)
|
Edible categories
|
Species name
|
Family
|
Vernacular name*
|
Part used
|
Mode of Preparation
|
Spices
|
Alpinia nigra (Gaertn.) Burtt
|
Zingiberaceae
|
Thrai (Rea), Tara (Ben)
|
Stem Pith
|
Stem pith is cooked with any dish.
|
|
Zanthoxylum rhetsa (Roxb.) DC.
|
Rutaceae
|
Muiching (Rea),
|
Leaf
|
Leaf is added and cooked in any cuisine.
|
|
Ocimum americanum L.
|
Lamiaceae
|
Manda (Rea), Ban tulsi (Ben)
|
Leaf and Stem
|
Leaf and stem is cooked along with any cuisine.
|
|
Trachyspermum roxburghianum (DC.) H.Wolff
|
Apiaceae
|
Khundrupui (Rea)
|
Leaf and Stem
|
Leaf and stem is cooked along with any cuisine.
|
|
Homalomena aromatica Schott
|
Araceae
|
Kaimaitru (Rea), Gandagi (Ben)
|
Stolon
|
Young fresh stolon is added in certain dish.
|
Vegetables
|
Neptunia oleracea Lour.
|
Fabaceae
|
Thoraiha (Rea)
|
Leaf and Stem
|
Leaf and stem is stir fried as eaten as side dish.
|
|
Oroxylum indicum (L.) Benth. ex Kurz
|
Bignoniaceae
|
Taukharung (Rea)
|
Fruit
|
Fruit skin was peeled and pulp is stir fried and eaten.
|
|
Leucaena leucocephala (Lam.) de Wit
|
Fabaceae
|
Wakre ste (Rea)
|
Fruit
|
Fruit is boiled mildly and mix with salads.
|
|
Senegalia pennata (L.) Maslin
|
Fabaceae
|
Muikambu (Rea)
|
Leaf
|
Young leaf is eaten by steaming.
|
Fruit
|
Flacourtia indica (Burm.f.) Merr.
|
Salicaceae
|
Pahela (Rea), Tokroi (Ben)
|
Fruit
|
Fruit is eaten when ripe.
|
*Vernacular names: Reang (Rea), Bengali (Ben)
Proximate composition and nutritional values of selected species
The proximate composition of selected bioresource species is presented in Table 2. Based on the percentage of the ten studied samples, total carbohydrate (%) content range from 3.65%˗13.34%; crude Protein (%) content range from 1.23%˗10.43%; crude fats (%) content range from 0.05%˗2.375%; total energy content range from 41.055 Kcal - 79.86 Kcal; moisture content was found to vary from 73.81% ˗ 94.95% in fresh weight, and the ash content of these plants ranged from 7.61% ˗ 42.16% in dry weight. As our result depicted (Figure 1), Oroxylum indicum has a relatively high carbohydrate content (13.34%), followed by Flacourtia indica (13.23%), Homalomena aromatic (8.88%) and the least belongs to Zanthoxylum rhetsa (3.65%). The highest protein content was observed in Trachyspermum roxburghianum (10.43%), followed by Homalomena aromatica (9.74%), Neptunia oleracea (8.74%), and the least was Ocimum americanum (1.23%). The highest fats content was observed in F. indica (4.25%), S. pennata (3.375%), Zanthoxylum rhetsa (2.975%), Trachyspermum roxburghianum (2.755%), Ocimum americanum (2.375%), Oroxylum indicum (2.175%), Leucaena leucocephala (1.91%), Neptunia oleracea (1.825%), Alpinia nigra (1.775%) and Homalomena aromatica (1.525%). The highest nutritive value (Total energy) was recorded in Flacourtia indica (107.97 Kcal), followed by Oroxylum indicum (106.855 Kcal), Homalomena aromatica (88.205 Kcal) and the lowest in Alpinia nigra (41.055 Kcal).
The highest moisture content was observed in Alpinia nigra (94.95%), Homalomena aromatica (94.21%), and Oroxylum indicum (89.5%), while the least was Zanthoxylum rhetsa (73.81%). The highest ash content was observed in Trachyspermum roxburghianum (42.16%), Neptunia oleracea (37.8%), and Homalomena aromatic (36.98%), while the least was observed in Senegalia pennata (7.68%).
Table 2: Proximate composition of the selected wild edible plant species
|
Species
|
Carbohydrate (%)
|
Protein (%)
|
Fats (%)
|
Total Energy (%)
|
Moisture (%)
|
Ash (%)
|
Alpinia nigra
|
3.93±0.67
|
2.34±0.06
|
1.775 ± 0.08
|
41.055
|
94.95±0.24
|
34.78±1.13
|
Zanthoxylum rhetsa
|
3.65±0.37
|
3.82±0.1
|
2.975±0.4
|
56.655
|
73.81±0.34
|
35.16±1.17
|
Ocimum americanum
|
5.21±0.70
|
1.23±0.04
|
2.375 ± 0.02
|
47.135
|
86.49±0.30
|
21.77±1.59
|
Trachyspermum roxburghianum
|
4.81 ± 0.09
|
10.43 ± 0.19
|
2.1 ± 0.05
|
79.86
|
89.29 ± 0.77
|
42.16±2.13
|
Homalomena aromatica
|
8.88±0.69
|
9.74±0.05
|
1.525±0.39
|
88.205
|
94.21±0.31
|
36.98±0.8
|
Neptunia oleracea
|
6.88 ± 0.05
|
8.74 ± 0.46
|
1.825 ± 0.08
|
78.905
|
82.25 ± 0.26
|
37.8±1.97
|
Oroxylum indicum
|
13.34±0.29
|
8.48±0.05
|
2.175±0.4
|
106.855
|
89.5±0.15
|
12.15±1.08
|
Leucaena leucocephala
|
5.14±0.23
|
5.88±0.02
|
1.91±0.7
|
61.27
|
78.1±0.65
|
12.13±1.61
|
Senegalia pennata
|
4.27±0.26
|
3.96±0.39
|
3.375±0.18
|
63.295
|
80±0.42
|
7.68±0.71
|
Flacourtia indica
|
13.23±0.28
|
4.20±0.02
|
4.25±0.28
|
107.97
|
76.17±0.87
|
25.07±0.22
|
*Each Triplicate experimental data (n=3) is represented as Mean±standard deviation
Comparative concentration of elemental composition in the ash of the selected species
The quantitative concentration (Wt %) of six main elements constituent have been studied from the ten selected wild edible plant species. The chemical composition of the basic ash components (Mg, P, K, Ca, Fe, Cl) was determined by energy dispersive spectrometry (EDS). X-ray microanalysis data are presented in the form of standard protocols which contain the microstructure picture of the studied sample; the data in weighting and atomic correlation, spectra and histograms were recorded as shown in Figure 2.
Micronutrient analysis
The results of micronutrients in each studied edible plant were noted (Table 3). In Alpinia nigra the proportion of K (18.23%) is detected to be highest, followed by P (1.72%), Ca (1.57%), Mg (1.03%), and Cl (0.97%). In Zanthoxylum rhetsa, the proportion of K (9.55%) is highest, followed by Mg (2.94%), Ca (2.71%), Cl (0.75%) and Fe (0.21%). Ocimum americanum consists high proportion of K (20.89%), Ca (13.23%), P (3.81%), Mg (2.98%) and Cl (3.61%). In Trachyspermum roxburghianum higher proportion of K (17.02%) is observed, followed by Cl (4.84%), Ca (2.36%), Mg (0.74%) and P (0.48%). In Homalomena aromatic, the highest proportion of K (42%) is observed, followed by Cl (8.58%), Ca (2.66%) and Fe (0.23%).
Neptunia oleracea has the highest amount of K (14.64%), followed by Ca (1.53%), Cl (1.24%), Mg (0.88%) and P (1.76%). In Oroxylum indicum, K (25.12%) is the highest, followed by Ca (7.73%), P (5.09%), Mg (4.27%), Cl (3.51%) and Fe (0.28%). In Leucaena leucocephala Ca (9.28%) content is highest, followed by K (8.79%), Cl (5.53%), Mg (2.28%), P (1.35%) and Fe (0.17%). In Senegalia pennata, the mineral contents observed are K (34.15%), P (12.17%), Cl (4.19%), Ca (3.78%), Mg (2.19%) and Fe (0.11%). Lastly, Flacourtia indica has a higher minerals proportion in K (31.84%) followed by Ca (7.09%), Cl (5.88%), P (2.11%), Mg (1.23%) and Fe (0.2%) respectively (Figure 3).
Table 3: Quantitative Wt %) of 5 main elements constituent in the ash sample
Element
|
Weight (%) of 10 studied species
|
A. nigra
|
Z. rhetsa
|
O. americanum
|
T. roxburghianum
|
H. aromatica
|
N. oleracea
|
O. indicum
|
L. leucocephala
|
S. pennata
|
F. indica
|
Mg
|
1.03
|
2.94
|
2.98
|
0.74
|
-
|
0.88
|
4.27
|
2.28
|
2.19
|
1.23
|
P
|
1.72
|
-
|
3.81
|
0.48
|
-
|
1.76
|
5.09
|
1.35
|
12.17
|
2.11
|
K
|
18.23
|
9.55
|
20.89
|
17.02
|
42
|
14.64
|
25.12
|
8.79
|
34.15
|
31.84
|
Ca
|
1.57
|
2.71
|
13.23
|
2.36
|
2.66
|
1.53
|
7.73
|
9.28
|
3.78
|
7.09
|
Fe
|
-
|
0.21
|
-
|
-
|
0.23
|
-
|
0.28
|
0.17
|
0.11
|
0.2
|
Cl
|
0.97
|
0.75
|
3.61
|
4.84
|
8.58
|
1.24
|
3.51
|
5.53
|
4.19
|
5.88
|
Antioxidants DPPH Scavenging
The free radical scavenging activity of the ethanolic extracts of A. nigra, Z. rhetsa, O. americanum, T. roxburghianum, H. aromatic, N. oleracea, O. indicum, L. leucocephala, S. pennata and F. indica was performed at various concentrations ranging from 100˗500 µg/ml (Table 4). Ascorbic acid (Vitamin C) was used as a standard antioxidant agent. IC50 value of the DPPH scavenging assay for the studied sample was tabulated in Table 5. It was found that in the lowest concentration (100µg/ml), the percentage scavenging is lower than the higher concentration (500µg/ml); these suggest that the percentage of free radical scavenging activity increase with the increase of sample concentration in a dose-dependent manner.
Table 4: DPPH scavenging activity of the studied samples showing Antioxidant potentials
|
% DPPH scavenging
|
Species name
|
100 (µg/ml)
|
200(µg/ml)
|
300(µg/ml)
|
400(µg/ml)
|
500(µg/ml)
|
A. nigra
|
16.18±2.63
|
26.48±0.64
|
36.14±0.65
|
41.53±2.88
|
49.19±1.8
|
Z. rhetsa
|
41.86±1.58
|
77.25±0.71
|
91.07±0.8
|
91.78±0.85
|
91.4±0.67
|
O. americanum
|
36.64±0.46
|
59.44±0.61
|
78.12±0.1
|
90.53±0.55
|
91.13±0.23
|
T. roxburghianum
|
25.57±0.63
|
38.83±0.68
|
50.92±0.84
|
63±0.28
|
74.22±0.04
|
H. aromatica
|
34.46±0.3
|
56.83±0.59
|
78.01±1.12
|
90.15±1.67
|
94.88±0.43
|
N. oleracea
|
7.68±1.1
|
23.68±0.35
|
36.62±0.84
|
48.25±0.7
|
51.97±0.39
|
O. indicum
|
36.04±0.06
|
63.75±2.56
|
77.97±0.12
|
90.65±0.53
|
92.07±0.2
|
L. leucocephala
|
56.56±0.94
|
87.59±0.3
|
93.33±0.06
|
94.03±0.41
|
93.39±0.05
|
S. pennata
|
7.68±0.73
|
23.68±0.82
|
36.62±1.66
|
48.25±1.47
|
51.97±0.67
|
F. indica
|
12.53±0.35
|
23.89±0.99
|
31.56±0.53
|
39.19±0.18
|
51.66±0.88
|
Vit C
|
91.91±1.58
|
92.02±0.94
|
92.13±1.05
|
92.13±0.45
|
91.91±0.97
|
Triplicate experimental data (n=3) is represented as Mean±standard deviation
Our results show that L. leucocephala possessed the lowest IC50 (125.4±1.78) value, followed by Z. rhetsa, which indicates a high antioxidant activity; whereas F. indica fruit extract demonstrated higher IC50 (485.44±5.82), suggesting low antioxidant activity (Figure 4). The decreasing order of free radical scavenging activity in terms of IC50 value of the studied plant extracts was in the following: Vit. C> L. leucocephala > Z. rhetsa > O. indicum > O. americanum > N. oleracea > T. roxburghianum > H. aromatica > S. pennata > A. nigra > F. indica.
Table 5: IC50 value of DPPH Scavenging assay for the studied sample
|
|
Sample name
|
IC50
|
|
|
A. nigra
|
456.86±1.01
|
|
|
Z. rhetsa
|
162.24±1.04
|
|
|
O. americanum
|
198.78±0.42
|
|
|
T. roxburghianum
|
305.87±2.04
|
|
|
H. aromatica
|
365.15±2.83
|
|
|
N. oleracea
|
202.18±2.89
|
|
|
O. indicum
|
196.25±3.12
|
|
|
L. leucocephala
|
125.4±1.78
|
|
|
S. pennata
|
444.96±4.22
|
|
|
F. indica
|
485.44±5.82
|
|
|
Vit C
|
47.07±2.56
|
|
Experimental data represented as Mean±standard deviation