Spices and herbal plants contain metal ions over a wide range of
concentrations. Metals can have important positive or negative
roles in human life. Twenty-three elements have known physiological
activities in humans and other mammals. Some of these elements,
including iron, zinc and copper, are considered essential.
Other metal ions such as cadmium, lead and mercury have toxic
roles in biochemical reactions on our body. The metals vanadium,
chromium, manganese, iron, cobalt, copper, zinc and molybdenum;
and the non-metals selenium, fluorine, and iodine are trace elements
that belong to the category of micronutrients, which are
needed by the human body in very small quantities (generally less
than 100 mg/day). Other elements are considered to be macronutrients,
e.g. sodium, calcium, magnesium, potassium, chlorine, etc.,
which are required in larger quantities. Some trace elements are
essential components of biological structures, but they can also
be toxic at concentrations beyond those necessary for their biological
functions. Examples of these metals include cobalt, copper,
chromium and nickel (Fraga, 2005). For example, at trace levels,
nickel is beneficial for the activation of some enzyme systems however,
its toxicity at higher levels is more prominent. Fortunately,
nickel toxicity in humans is not a very common occurrence because
the absorption of nickel is very low (Onianwa, Lawal, Ogunkeye, &
Orejimi, 2000). In biological systems, trace elements are mostly
Spices and herbal plants contain metal ions over a wide range ofconcentrations. Metals can have important positive or negativeroles in human life. Twenty-three elements have known physiologicalactivities in humans and other mammals. Some of these elements,including iron, zinc and copper, are considered essential.Other metal ions such as cadmium, lead and mercury have toxicroles in biochemical reactions on our body. The metals vanadium,chromium, manganese, iron, cobalt, copper, zinc and molybdenum;and the non-metals selenium, fluorine, and iodine are trace elementsthat belong to the category of micronutrients, which areneeded by the human body in very small quantities (generally lessthan 100 mg/day). Other elements are considered to be macronutrients,e.g. sodium, calcium, magnesium, potassium, chlorine, etc.,which are required in larger quantities. Some trace elements areessential components of biological structures, but they can alsobe toxic at concentrations beyond those necessary for their biologicalfunctions. Examples of these metals include cobalt, copper,chromium and nickel (Fraga, 2005). For example, at trace levels,nickel is beneficial for the activation of some enzyme systems however,its toxicity at higher levels is more prominent. Fortunately,nickel toxicity in humans is not a very common occurrence becausethe absorption of nickel is very low (Onianwa, Lawal, Ogunkeye, &Orejimi, 2000) ในระบบชีวภาพ ติดตามองค์ประกอบเป็นส่วนใหญ่
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