The purpose of this paper was to determine the content of microelements (Fe, Mn, Zn, Cu, Co, Cr, Ni, Pb and Cd) in the following medicinal plant species: lovage, garden iris, garden angelica, marshmallow, soapwort and common valerian. The contents of the investigated microelements were determined by means of atomic absorption spectrophotometry. The results obtained indicate that the investigated microelements could be arranged in the following order with respect to their content in the medicinal plants: Fe>Mn>Zn>Cu> Pb>Ni>Cr>Co>Cd. Statistically significant differences were found between the investigated medicinal plants with respect to the content of almost all microelements. The results obtained in this investigation are important from the standpoint of the use of these medicinal plants for prophylactic and therapeutic purposes.
Microelements such as iron, manganese, zinc, copper and cobalt have an important physiological role in human organism while metals like nickel, lead and cadmium are very toxic substances. Microelements enter human body mainly by consumption of food of plant and animal origin. There are not much data on the content of microelements in various medicinal plants that are grown in our country. Most of the work on this problem has been carried out by the Institute for Medicinal Plant Research in Belgrade. Microelements were determined in several plant species: thyme (Maksimović et al., 1998), peppermint (Radanović et al., 1998), sage (Maksimović et al., 1999) and chamomile (Stevanović et al., 1997).
The purpose of this paper was to determine the content of microelements (Fe, Mn, Zn, Cu, Co, Cr, Ni, Pb and Cd) in the following medicinal plant species: lovage, garden iris, garden angelica, marshmallow, soapwort and common valerian. No research of this kind has been carried out in Yugoslavia. These plants are grown in our country and are used for various purposes (Stepanović, 1998). Lovage is grown in gardens and yards as an aromatic plant and it can be used for the treatment of disturbances in the work of digestive organs. It is also used as a diuretic. Garden iris is mostly grown in eastern parts of Serbia. Its root is used in folk medicine for coughing up and as a diuretic. Garden angelica is rather rare in our country. It is used for the preparation of drinks for the treatment of stomach catarrh, inflammation of large intestine and other stomach diseases. Marshmallow is a widespread plant species in Serbia, especially in the province of Vojvodina. This plant species has been used for the treatment of catarrh of respiratory organs since ancient times. It is very effective against coughing. Common valerian is also a widespread medicinal plant species in Yugoslavia, which is used since ancient times for the treatment of nervous disturbances. Root of valerian has wide application in official medicine while its essential oil is also used for soap production and in cosmetic industry.
We hope that the results presented in this paper will contribute to the better use of the investigated medicinal plant species for therapeutic and prophylactic purposes.
Samples of the aforementioned plant species were taken from the experimental field of the Institute for Medicinal Plant Research "Dr Josif Pančić", which is located in Pančevo. There were six variants in the experiment. These variants represent the investigated plant species. Each variant was replicated four times. Plants were grown on humogley soil the samples of which were taken for chemical analysis. The following soil chemical properties were determined: pH in H2O and 1M KCl, CaCO3, humus, total nitrogen, available phosphorus and potassium, and DTPA-extractable Fe, Mn, Zn, Cu, Co, Pb, Ni and Cd. Standard methods of soil chemical analysis (Stevanović et al., 1996) were used for the determination of the aforementioned soil properties.
After necessary preparations (oven drying and grinding) the contents of the investigated microelements were determined in plant species by the method of atomic absorption spectrophotometry. This was done after digestion of plant samples with nitric and perchloric acid (Jones and Case, 1990).
The obtained results were statistically analyzed (analysis of variance and lsd test).
The results of the determination of some important chemical properties of humogley soil are presented in table 1.
| pH in H2O | 6.60 | available Fe (ppm) |
58.0
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| pH in KCl | 5.70 | available Mn (ppm) |
99.0
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| CaCO3 (%) | 0.00 | available Zn (ppm) |
1.2
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| humus (%) | 3.54 | available Cu (ppm) |
3.0
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| total N (%) | 0.21 | available Co (ppm) |
0.7
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| available P (mg P2O5/100 g) | 12.0 | available Pb (ppm) |
3.1
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| available K (mg K2O/100 g) | 38.0 | available Ni (ppm) |
1.5
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| available Cd (ppm) |
0.12
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Humogley soil in Pančevo is weakly acid and has medium content of humus. The soil is well supplied with total nitrogen. The content of available phosphorus is medium, whilst level of available potassium in the investigated soil is high. As far as the content of available micronutrients is concerned the following can be said. The humogley soil has very high contents of iron, manganese and copper. The content of DTPA-extractable zinc is at the level of moderate supply. Available cadmium was present in lowest amounts.
The results of the determination of microelements (Fe, Mn, Zn, Cu, Co, Cr, Ni, Pb and Cd) in the investigated medicinal plant species are presented in table 2.
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Garden iris Garden angelica Marshmallow Soapwort Common Valerian |
803 999 292 1268 1872 |
31.5 46.3 10.0 57.8 31.0 |
28.3 27.5 17.8 13.5 20.3 |
12.0 13.8 3.8 3.0 12.3 |
2.8 2.8 2.5 2.5 2.3 |
3.8 4.0 2.8 4.0 4.3 |
4.3 4.4 2.0 4.5 6.1 |
3.8 4.0 3.3 6.9 5.2 |
0.70 0.55 0.65 0.55 0.63 |
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The results obtained indicate that the investigated microelements can be arranged in the following order with respect to their content in the medicinal plants: Fe>Mn>Zn>Cu>Pb> Ni>Cr>Co>Cd. Namely, the average values for the contents of these elements are: 1039 ppm for Fe, 35.2 ppm for Mn, 22.0 ppm for Zn, 8.9 ppm for Cu, 4.6 ppm for Pb, 4.4 ppm for Ni, 3.8 ppm for Cr, 2.6 ppm for Co and 0.58 ppm for Cd. This order does not coincide with the one obtained for available microelements in the soil.
Of all the investigated plant species common valerian has the highest content of iron. This result is important from the standpoint of the use of this plant species for the prevention of nutritional anemia. High level of Fe was also registered in soapwort. Lowest content of iron was found in marshmallow - plant species most often used in pharmaceutical industry. This plant species has also lowest contents of Mn, Cr, Ni and Pb. As far as other plant species are concerned the following can be said. Soapwort has highest contents of Mn and Pb. Highest levels of Cu were registered in garden angelica, while garden iris has highest contents of Zn and Cd. It is important to mention that statistically significant differences were found between the investigated medicinal plants with respect to the content of almost all microelements. These differences between the plants are genetically induced since they were grown on the same soil. Genetic specificity of mineral nutrition is mostly expressed in the case of Fe where the highest value for the coefficient of variation was obtained. There were no significant differences in the contents of Co and Cr. Microelements such as Pb, Ni and Cd are present in amounts below toxic concentrations of these elements for crops (Kastori et al., 1997). Since determined contents of the aforementioned elements in the plant species (grown on this uncontaminated soil) are somewhat higher than usual values for plants it is essential to pay special attention if these species are grown on soils contaminated with these metals.
The following conclusions can be drawn on the basis of the results obtained:
The investigated microelements can be arranged in the following order with respect to their content in the medicinal plants: Fe>Mn>Zn>Cu>Pb>Ni>Cr>Co>Cd. Highest content of Fe (1872 ppm) was found in common valerian. Contents of Pb, Ni and Cd in the investigated species are below toxic concentrations of these elements for crops.
Statistically significant differences between the plant species are explained by genetic specificity of mineral nutrition.
Determination of microelements in the investigated plant species is important from the following two aspects: medicinal value of these species and their cultivation on various soils.
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Kastori R., Petrović N. and Arsenijević-Maksimović I. (1997): Heavy metals and plants, In: Kastori R. (Ed.), Heavy Metals in the Environment, Novi Sad, 195-257.
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Stevanović D., Jakovljević M. and Maksimović S. (1997): Soil as a factor for chamomile production, In: Kojić M. (Ed.), Chamomile (Chamomilla recutita (L.) Rausch.), Belgrade, 72-79.