Levels of organophosphorus pesticides in medicinal plants commonly consumed in Iran

Medicinal plants are widely consumed as raw materials for pharmaceutical preparations and as supplements for dietetic products and especially for “self-medications” in the general population and they are also commonly used in health care products, food additives or supplementary foods [1]. Therefore, a large quantity of them is consumed in both daily life and pharmaceutical industry. In addition, medicinal plants are increasingly favored because of their distinct curative effects and naturally physiologic properties. However, pesticides are often used in order to improve productivity and profit margins in the production of medicinal plants. Hence pesticide residues in medicinal plants become pitfalls in safety and present obstacles to be acknowledged by the international community. Up to now, many international organizations and countries have set up regulations concerning the pesticides in the plants and plant products [2]. In recent years, with the significant improvements in pesticides analytical techniques and tremendous concerns in the safety of consumers’ products, the pesticides residues in foods have been more strictly monitored in the aspects such as classes and/or amounts as well as MRLs (maximum residue levels) in the developed countries [1-4]. The results of the works on pesticide residues in crude herbal materials indicate that the presence of pesticide residues is quite common [5-7]. In Iran, up till now, studies dealing with the detection of pesticide residues in spice and medicinal plants have been lacking. This study was conducted to have a view of the situation of medicinal herb pollution by organophosphorus pesticides (OPPs) in Iran. To achieve this aim the levels of frequently used OPPs in 50 samples of five kinds of medicinal plants which are consumed mostly in Iran was determined by a sensitive headspace solid-phase GC-MS method developed in the previous studies [8-10].Ten samples of each group of plant, Zataria (Zataria multiflora), Matricaria