الفهرس 
coverOnly 14 pages are availabe for public view
 |  | from | 105 |  |  |
| | | from | 105 | | |
Abstract
In Egypt, there is an increasing consumer demand for herbal medicines, and various kinds of wild and cultivated medicinal plants for the treatment of several ailments. Lack of environmental safeguards including processing and storage, may lead to infestation of these medicinal plants with insect pests or contamination with insecticides and heavy metals, affecting their economic value and therapeutic activity.
The present study aimed to collect, identify insect pests; detect pesticide residues and heavy metals in seven medicinal plants in Egypt.
Samples of anise, caraway, kaff-maryam, licorice, roselle, salamekki and half-barr (280 samples) were collected from local markets at four Governorates, Cairo and Sinai Governorates during January and June; and during February and July 2008 from Aswan and Matrouh Governorates. Packed samples were collected from five local supermarkets and pharmacies in Cairo Governorate during January and June 2009. Detection and identification of insect pests took place according to the available keys. Detection of pesticide residues and heavy metals in medicinal plant samples was done using WHO technique 1992.
Results indicated that seven coleopteran pests belonging to five families were recorded in the samples of medicinal plants except half-barr, which was free from any infestation. The identified insect pests were: Tribolium confusum Jacquelin du Val., Stegobium paniceum L., Lasioderma serricorne F., Rhizopertha dominica, Trogoderma versicolor, Trogoderma granarium Everts and Oryzaephilus surinamensis (L.). Tribolium confusum Jacquelin du Val. was the most commonly detected species and Oryzaephilus surinamensis (L.) was the least detected species. The investigated medicinal plants could be arranged in a descending order, on the basis of the total number of pests they harbored as follows: caraway (402 individuals), licorice (223 individuals), roselle (189 individuals), anise (117 individuals), salamekki (95 individuals) then kaff-maryam (51 individuals). On the other hand, all samples of half-barr collected from the different Governorates were free from insect infestation. Also the packed samples were free from insect infestation.
HCB (organochlorine pesticide) was the predominant compound in most tested medicinal plants at varying levels. DDT and its derivatives have also been detected at lower residue levels in most samples of medicinal plants under investigation with some exceptions.
Among organophosphorus pesticides profenophoes has been detected at levels higher than the MRLs in some unpacked and packed samples. Cyanox, dimethoate and chloropyriphos methyl have also been frequently detected.
Half-barr represented the most contaminated medicinal plants with pesticide residues. On the other hand Cairo and Sinai Governorates showed the highest contamination rates among medicinal plants.
Packed anise samples were most contaminated with pesticide residues followed by licorice. Contamination with HCB, dieldrin, pp’ DDE and endrin aldehyde has violated the MRLs. Dimethoate was the most pesticide frequently detected in packed medicinal plants but at levels below the MRLs. Again profenophoes has been detected at levels higher than MRLs, in packed samples.
Heavy metal contents in the collected samples have been detected at varying levels. Lead has violated the MPLs in all medicinal
plants (unpacked & packed) from Cairo, Sinai and Matrouh Governorates. On the other hand, no lead residues were detected in samples collected from Aswan Governorate. Cadmium was also detected at levels higher than MPLs in anise samples from Matrouh Governorate. Ferrous has also been detected at relatively high levels in licorice (unpacked & packed), roselle (packed), anise (unpacked) and half-barr.
Conclusions
from this study, it could be concluded that all the detected insect pest species infesting the examined medicinal plants were those usually infesting stored products in warehouses.
Excessive and unwise application of conventional insecticides for the control of insect pests has caused an alerting situation concerning pesticide residues in medicinal plants.
Moreover, detected levels of lead have violated the EOS permissible levels and constitute a serious threat and health hazards to the consumer especially children.
Recommendations
Strict quality control measures such as purity and standardization are essential before allowing medicinal plants and herbs to the markets.