Leka Mandic

COMPOSITION AND ANTIMICROBIAL ACTIVITY OF ESSENTIAL OILS OF SOME MEDICINAL AND SPICE PLANTS

An examination was made on the chemical composition and antimicrobial activity of four medicinal plants Carum carvi, Coriandrum sativum, Hyssopus officinalis, and Eucalyptus globulus, the first three of which are also used as culinary spice herbs. Carum carvi L. and Coriandrum sativum L. belong to the Apiacea family. In traditional medicine, Carum carvi is used in the form of a tea as a digestive and diuretic [1]. Coriandrum sativum has been used since ancient times; it was found in pharaonic tombs where it was used for embalming, and there is mention of it in the Bible. It is used as a medicine against flatulence and as a diuretic [1], and it also has an anticonvulsive effect [2]. The essential oils of these two plants are used as spices in preparing food. Hyssopus officinalis L. and Eucalyptus globulus Lab. belong to the Lamiaceae and Myrtaceae families, respectively, and they are used in folk medicine to treat respiratory diseases [1]. The aim of this paper was to determine the chemical composition of the essential oils of the said plants and examine their activity against the growth of bacteria (Staphylococcus aureus ATCC 25923, Streptococcus haemolyticus group A, Escherichia coli ATCC 25922, Enterecoccus faecalis ATCC 29212, and Pseudomonas aeruginosa ATCC 27853), and fungi (Candida albicans ATCC 10231). Eucalyptus globulus was collected at the Montenegrin Coast and all the rest of the plants were grown in the fields of Vojvodina (Northern Serbia). The essential oils were obtained from the fruits of Carum carvi and Coriandrum sativum and the leaves of Hyssopus officinalis and Eucalyptus globulus by the steam distillation method following Procedure III of the Yugoslav Pharmacopoeia [3]. The GC and GC/MS analyses were used for determination of the essential oil composition. Percentages of the main components of the essential oils investigated are given in Table 1. The essential oils of the plants examined are of different chemical compositions, and monoterpenes are distributed the most. By comparison of the composition of the essential oils of the plants mentioned with the literature data [4] and [5], it was concluded that it was dependent on the geographic region and plant growing conditions. The antimicrobial activity of the essential oils of the plants investigated was determined by the disc-diffusion method [6] and [7]. Tables 2 gives MIC (minimum inhibitory concentration) values and inhibition zone diameters for three different essential oil concentrations. The inhibition zone diameters were compared with the reference antibiotics, as shown in the tables. As Enterecoccus faecalis ATCC 29212and Pseudomonas aeruginosa ATCC 27853 were not inhibited by the essential oils of the plants mentioned, their results are not given in the Tables. The broadest inhibitory activity spectrum was exhibited by the essential oils of Carum carvi and Hyssopus officinalis, and the narrowest one by Eucalyptus globulus. The antimicrobial activity of certain oils (Carum carvi, Hyssopus officinalis, and Eucalyptus globulus) against Staphylococcus aureus ATCC 25923 was higher than or equal to the reference value. A pronounced activity against Candida albicans ATCC 10231 was also expressed by all the essential oils with the exception of the essential oil of Hyssopus officinalis.

Microbial Characteristics of Vertisol Under Different Fertilization Systems

The present study evaluates the effect of increasing rates of mineral nitrogen (90; 120; 150 kg×ha-1), liquid manure (80 t×ha-1) and solid manure (45 t×ha-1) on the microbial properties of vertisol (total number of microorganisms, numbers of actinomycetes and cellulolytic microorganisms) under maize. The research results showed dependence of the number of the test groups of microorganisms on the type and rate of fertilization, as well as on the date and zone of sampling. Namely, lower nitrogen fertilization rates (90 and 120 kg×ha-1) induced a significant increase in the total number of microorganisms, whereas the high rate (150 kg×ha-1) had a depressive effect, especially in maize edaphosphere. However, the numbers of actinomycetes and cellulolytic microorganisms were not reduced under these treatments. The organic fertilizers applied had a stimulatory effect on the above soil biological parameters.

Evaluation of Mineral and Bacterial Fertilization Influence on the Number of Microorganisms from the Nitrogen Cycle in Soil under Maize

In 2006, the influence of different rates of applied mineral fertilizers and their combinations with bacterial inoculants [nitrogen (N)–fixing Klebsiella planticola and Enterobacter spp.] on the number of microorganisms from the N cycle in a Cambisol and the yield of maize was evaluated in this study. The results obtained implied that high rates of mineral fertilizers brought about an increase in the number of fungi and a decrease in the number of Azotobacter spp., oligonitrophiles, ammonifiers, and nitrifiers in soil. Combined application of microbial inoculants and low rates of mineral fertilizers resulted in the greatest increase in the number of Azotobacter spp., oligonitrophiles, and ammonifiers in soil. The greatest number of soil nitrifiers, as well as the grain yield of maize studied, were determined in the variants where combinations of the microbial inoculants and low and high rates of mineral fertilizers were applied.

Chemical composition and yield of maize green biomass as affected by bacterial and mineral fertilization

The purpose of the study was to evaluate the influence of an application of different rates of composite mineral fertilizers and their combination with bacterial inoculants (N-fixing Klebsiella planticola and Enterobacter spp.) on chemical composition and yield of the maize green biomass (without spikes) on acid Eutric Cambisol during the two growing seasons: 2006 and 2008. Unfertilized soil was used as a control. The contents of nitrogen, phosphorus, potassium and crude proteins in biomass samples were determined three times during the maize vegetation season, as follows: stage of intensive growth, milk-waxy maturity stage and full maturity stage. Measuring of the green biomass yield was carried out at the end of the vegetation. The results of the study showed that the use of high rates of composite mineral fertilizers and their combination with bacterial inoculants resulted in increased contents of nitrogen, phosphorus, potassium and crude proteins in the maize biomass during the both study years, which was noticeably observed in the stage of intensive growth. The highest increase in the biomass yield was obtained by the same mentioned treatments, although the combination of bacterial inoculants and lower rates of mineral fertilizers resulted in higher yields comparing to the application of lower rates of the pure mineral nutrients. The data suggest that the studied bacterial inoculants can be used in further investigations as the potential agents of new biofertilizers for improved maize production and other agriculture crops in animal nutrition.

THE INFLUENCE OF MINERAL AND BACTERIAL FERTILIZATION ON THE NUMBER OF FUNGI IN SOIL UNDER MAIZE

The aim of this study was to evaluate the influence of an application of different rates of mineral fertilizers and their combination with associative N-fixing Klebsiella planticola and Enterobacter spp., and sampling period on the number of fungi in Cambisol and grain yield of maize. The investigation was conducted on Mladenovac experimental station and in the Laboratory of Institute of Soil Science, Belgrade, during 2006. Unfertilized soil was used as the control soil. Each of the studied variants was carried out in three replications. The effect of the studied fertilizers was determined three times during the maize growing season, the number of fungi being determined by indirect dilution method on Czapek nutritive medium. The results of the study showed that all fertilization variants studied influenced, more or less, fungal growth in the study soil. However, the applied high content of mineral nitrogen, phosphorus and potassium, as well as their combination with bacterial inoculants brought about the highest increase in the number of fungi during all studied vegetation periods of maize. The highest increase in the number of soil fungi was registered in the second sampling period. The highest increase in the grain yield of maize was obtained by combined application of microbial inoculants and high rates of mineral NPK fertilizers.