COMPARATIVE STUDY ON MINERAL ELEMENTS AND HEAVY METAL COMPOSITION OF ALLIUM SATIVUM CLOVES (NIGERIAN /INDIAN SPECIES) AND COSTUS AFER (KER GAWL) LEAF BY INDUCTIVELY COUPLED PLASMA-OPTICAL EMISSION SPECTROMETER (ICP-OES).

Anthonet Ndidiamaka Ezejiofor*, Jamal Akhtar Ansari and Abbas Ali Mahdi

ABSTRACT

The present study aimed at investigating two commonly and extensively used herbs namely Costus afer (ginger lilly) and Allium sativum (garlic) for their essential element and heavy metal composition and also to compare the Nigerian specie of Allium sativum to that of Indian species for their metal composition using a highly sensitive Inductively Coupled Plasma-Optical Emission Spectrometer (ICP-OES). Eighteen minerals elements (Ba, Be, Bi, B, Ca, Co, Cr, Cu, Fe, Mg, Mn, Mo, Ni, Se, Ag, Sr, V and Zn) and three heavy metals (As, Cd, Pb) concentration were determined for the first time in C.afer and A.sativum. Wet digestion method using a mixture of 2ml of concentrated HNO3:HClO4 (4:1 v/v), 1ml H2O2 and 1ml miliQ water was used for digestion of the samples using microwave in a Microwave Digestion System (MDS) and analyzed by ICP-OES. The results obtained revealed the following concentration of metals in C.afer leave in mg/kg dry weight: B= 18.36; Ba= 53.52; Bi=2.10; Ca=1017.42; Cd=0.42; Cr=0.18; Cu=6.66, Fe=303.66; Mg=4386.6; Mn=808.80, Mo=0.84;N=7.14, Pb=1.80; Sr=32.16; V=1.68 and Zn=24.24 while that of the Nigerian/India garlic cloves were B=2.72/1.54 ; Ba= 11.24/4.86; Bi=0.072/0.216;Ca=47.20/34.93; Cd= 0.036/ND; Cu= 2.69/1.67, Fe= 27.94/20.64; Mg=312.6/240.84; Mn=3.9/4.08, Mo=0.24/0.17;Ni=0.65/0.77, Pb=0.14/0.22; Sr=2.57/2.24; V=0.144/0.024 and Zn=8.59/8.32. Ag= As=Be=Co=Se were below the detectable limit in both C.afer and A.sativum, Cr was detected only in the C.afer. In conclusion, the concentrations of the essential element detected were higher in the C.afer leave than in garlic cloves in virtually all elements. The number of mineral element below detectable limit was same in both C.afer and A.sativm. Comparing the Nigerian and Indian garlic, there was no significant different between the elemental composition. In general, the levels of metals in the analyzed C. afer leaf and garlic cloves samples were found below the FAO/WHO maximum permissible limit; hence they are safe for human consumption and can be considered as a good source of essential nutrients.

Keywords: Ginger lilly, garlic, ICP-OES, essential elements, Heavy metal, MSD.