IC50 (µg/mL) values of iron metal chelating ability [For each solvent, values in the bar between the non-distilled plant materials and distilled plant extract, followed by a different letter (x, y) are significantly different (p < 0.05); For each extraction solvent, values in the bar within the non-distilled and distilled plant extract followed by a different letter (a, b, c, d, e and f etc.) are significantly different (p < 0.05)]