Abstract:
Vegetables are good sources of essential minerals that promote good health and
immunity. Information on the nutritional contents of indigenous vegetables is scarce.
Therefore, this study sought to ascertain the concentrations of macro and micro
elements in Solanum nigrum and Gynandropsis gynandra indigenous vegetables from
two agroecological zones (AEZs): upper midland (UM) and lower highland (LH) of
Kisii County, Kenya. Inductively coupled plasma-optical emission spectroscopy (ICP‒
OES-900 model with CAT NO-211-86000-96) was used for elemental analysis. The
highest concentration of Ca (53811.67±8.65mg/kg Dw) macro element was detected in
Solanum nigrum at Nyaura (UM), while a lower concentration of Al (45.83±2.54mg/kg
Dw) in Gynandropsis gynandra was detected at Nyamemiso (LH). For Gnandropsis
gynandra, the most abundant erythrocytic synthesis element was Fe (1856.67±15.28
mg/kg DW) for plants harvested from Nyanchwa (UM), and the least available element
was Cu (8.90±0.44 mg/kg DW) from plants in Kari (LH). In addition, Mg was the
hypoglycemic element with the highest concentration (5975.00±10.00 mg/kg DW) and
Cr lowest (3.16±0.45 mg/kg Dw) in G.gynandra from Matongo (UM). For Solanum
nigrum, the most erythrocytic synthesis element was Fe (1280.00±10.00 mg/kg Dw in
vegetables from Kiamabundu (UM), and the least element was Cu (9.08±0.15 mg/kg
Dw) in vegetables collected from Nyanchwa (UM), whereas Mg (4920.00±10.00 mg/kg
Dw) in vegetables from Nyabioto (UM) was the hypoglycemic element with the highest
concentration, while Cr(3.95±1.63mg/kg Dw) in veetables from Mariba (LH) had the
lowest concentration. The highest positive and significant correlation was observed
between Ca and Mg contents (r= 0.92, p<0.05 in Gynandropsis gynandra from LH
while, the highest negative and significant correlation was between Co and Cr (r = 0.88
P<0.05) in Gynandropsis gynandra from LH, while no correlation between Ca and Co,
(r=0.00, P >0.05) in Solanium nigrium from LH was observed. High levels of micro
elements were bio accessed as compared to macro elements for vegetables from UM. In
a general trend, elements in the two indigenous vegetables from UM were slightly
greater than those in the LH. Nonetheless, the differences in concentrations were
insignificant (P0.05). Enzymatically bio-accessed concentrations of Fe, Zn, Cr, Mg,
Mn, and Cu were higher than those obtained aquatically. The indigenous vegetables bio
avails substantial amounts of Fe and Cu, hence offering a good alternative in the
management of pernicious anaemia. In addition, substantial bio-accessible levels of Zn,
Mn, Mg, and Cr offer the potential for consumption and management of diabetes.
