The antimicrobial activity of several extracts and fractions of some Sideritis species (S. albiflora, S. brevibracteata and S. pisidica) was investigated by disc diffusion and broth microdilution methods against Escherichia coli ATCC 11230, Staphylococcus aureus ATCC 6538P, Klebsiella pneumoniae UC57, Micrococcus luteus La 2971, Micrococcus flavus ATCC 14452, Proteus vulgaris ATCC 8427, Pseudomonas aeruginosa ATCC 27853, Corynebacterium xerosis CCM 7064, Mycobacterium smegmatis CCM 2067, Bacillus subtilis ATCC 6633, Bacillus cereus ATCC 9730, Kluyveromyces fragilis NRRL 2415 and Rhodotorula rubra CCY. The methanol extract and chloroform fraction of S. pisidica, as well as the methanol extracts, butanol and chloroform fractions of both S. albiflora and S. brevibracteata showed good antimicrobial activity against some bacteria and all yeasts tested, with growth inhibition area diameters in the range 10-20 mm, and MIC values between 0.03 and 0.38 µl/ml. The results of the study support the use of these species in traditional medicine.
Antibacterial and antifungal activity of 2,4-dihydro-[1,2,4]triazol-3-one derivatives were examined by the disc-diffusion method (growth inhibition zone diameter in agar medium). The MIC's for the most active agents were determined. Of all the tested compounds, aminomethy1 derivatives of 2,4-dihydro-[1,2,4]triazol-3-one exhibit activity against the majority of microorganisms studied.
Phytosulfokine-α (PSK-α) (H-Tyr(SO3H)-Ile-Tyr(SO3H)-Thr-Gln- OH) (I), a sulfated growth factor universally found in both monocotyledons and dicotyledons, strongly promotes proliferation of plant cells in culture. The C-terminal truncated analog named PSK-β (Tyr(SO3H)-Ile-Tyr(SO3H)-Thr) (II) showed a 10-fold lower activity than that of the parent pentapeptide. Because PSK-α promotes proliferation and differentiation during the plant growth we undertook the studies on the influence of PSK-α on plant defense mechanisms in that period. In present studies on PSK-α (I), PSK-β (II), and its analogues, we performed a search of another biological properties. The aim of our investigation was evaluation of PSK-α, PSK-β and their selected analogues in relation to growth and development of plant pathogens, such as Phoma narcissi and Botrytis tulipae. In these studies we elaborated the synthesis of PSK-α or PSK-β and their 22 analogues modified by natural and non-natural amino acid residues. Peptides were synthesized by the solid phase method according to the Fmoc procedure on a Wang-resin. Free peptides were released from the resin by 95% TFA in the presence of EDT. Biological effect of these peptides was evaluated by test on the growth and development of pathogens of P. narcissi and B. tulipae.
Ziziphora species are traditionally used for treatment of different infectious and non-infectious diseases as antiseptic agents. The aim of this study was to evaluate the chemical composition of Ziziphora clinopodioides and Z. tenuir essential oils and their antifungal effects againt five strains of dermatophytes. GC and GC-MS methods were used for essentional oils analize. The anti-elastase activities were determined by porcine pancreatic elastase assays. 48 different compounds were identified in these two essential oils, which thymol, p-cymene, 1,8-cineole and γ-terpinene were their major components. The anti-dermatophyte activities of essential oils against dermatophytes showed that the essential oils (150 ppm) inhibited the mycelium growth, about 5–100%, which Z. clinopodioides essential oil had higher mycelium growth inhibition (28–100%) than that of Z. tenuir oil. The MIC and MFC values of essential oils were 0.01–1 μl/ml. 0.5 μl/ml essential oils inhibited porcine pancreatic elastase, dose-dependently. Due to the anti-dermatophyte and anti-elastase effects of Ziziphora sp., it can be considered as natural antifungal agent for more clinical and pre-clinical trials.
In the GC-MS analysis, 81 bioactive phytochemical compounds were identified in hexane extracts of Cirsium creticum and Cirsium italicum. Terpenoids constituted the main fractions of C. italicum (70.95%), while hydrocarbons were most abundant compounds of C. creticum (41.11%). The antibacterial activity and antifungal activity of extracts from two Cirsium species was tested using microdilution methods. According to the results of antibacterial activity, the highest inhibition effect of C. creticum was found on B. subtilis, E. coli and P. aeruginosa. The highest inhibition effect of C. italicum was found on B. subtilis. In the results of antifungal activity, the highest inhibition effect of C. creticum was found on P. chrysogenum and the highest inhibition effect of C. italicum was found on C. krusei. The present work is the first report on hexane extracts compounds of two Cirsium species as well as antibacterial and antifungal activities.
The objective of this study was to evaluate the in vitro antifungal properties of ethanol extracts and essential oils of medicinal plants from Serbia against Candida albicans (C. albicans) ATCC 10231. Ethanol extracts of fifteen plants were investigated, and their effects were compared with those of three different essential oils. The sensitivity of C. albicans to all plants was tested by the agar dilution method. The assay plates were estimated to contain 300, 150, 75, and 37.5 µg/ml of active extracts and 100, 50, 25, and 12.5 µg/ml of active essential oils. Inocula were applied to agar surfaces, giving approximately 106 cfu/ml of C. albicans. No inhibitory effects were observed for ethanol extracts of Hypericum perforatum and Salvia officinalis (MIC > 300 µg/ml). The most effective were the ethanol extract of Aesculus hippocastanum (MIC = 37.5 µg/ml) and the essential oil of Satureja kitaibelii (MIC = 12.5 µg/ml). Other plants showed MIC from 25 to 300 µg/ml. As far as we know, the inhibitory effects of these medicinal plants against the reference strain of C. albicans have not been commonly investigated in our country. Although the essential oil of Satureja kitaibelii shows strong activity against C. albicans, these results need clinical evaluation.
The aim of our study was to investigate fungistatic properties of glucosinolates from seeds of four cruciferous plants against Candida albicans, obtained from different sections of the gastrointestinal and respiratory tracts. The examined extracts were observed to exert different effects on fungi depending on the site of their isolation. The strongest antimycotic activity was reported for the extract obtained from seeds of broccoli – the extract appeared more effective than fluconazole. In contrast, upon the activity of white mustard seeds extract the size of the growth inhibition zone was similar to that yielded by fluconazole. Promising results of our experiments suggest the need to further investigate the field.
The aqueous extracts of leaf of Citrus aurantifolia L were assessed in vitro for inhibitory activity against Macrophomina phaseolina isolated from dry root rot specimens of Gingelly. The antifungal activity was determined by poison food technique. The extracts have shown dose dependent inhibition of mycelial growth of test fungi. The extracts were more effective in inhibiting Macrophomina phaseolina. The extracts of Citrus aurantifolia were found effective against Gingelly dry root rot pathogens. Further field experiments are to be carried out to recommend the extracts against the disease.
Aspergillus parasiticus is one of the most common fungi which contaminates peanuts by destroying peanut shells before they are harvested and the fungus produces aflatoxins. The aim of this study was to evaluate the antifungal activities of seventeen essential oils on the growth of the aflatoxigenic form of A. parasiticus in contaminated peanuts from commercial outlets in Georgia. The agar dilution method was used to test the antifungal activity of essential oils against this form of A. parasiticus at various concentrations: 500; 1,000; 1,500; 2,000; 2,500 ppm. Among the seventeen essential oils tested, the antifungal effect of cinnamon, lemongrass, clove and thyme resulted in complete inhibition of mycelial growth. Cinnamon oil inhibited mycelial growth at ≥ 1,000 ppm, lemongrass and clove oils at ≥ 1,500 ppm and thyme at 2,500 ppm. However, cedar wood, citronella, cumin and peppermint oils showed partial inhibition of mycelial growth. Eucalyptus oil, on the other hand, had less antifungal properties against growth of A. parasiticus, irrespective of its concentration. Our results indicate that the aflatoxigenic form of A. parasiticus is sensitive to selected essential oils, especially cinnamon. These findings clearly indicate that essential oils may find a practical application in controlling the growth of A. parasiticus in stored peanuts.
QSAR analysis of a set of previously synthesized 2,5,6-trisubstituted benzoxazole, benzimidazole and 2-substituted oxazolo(4,5-b)pyridine derivatives tested for growth inhibitory activity against Candida albicans, was performed by using the computer-assisted multiple regression procedure. The activity contributions for either heterocyclic ring systems or substituent effects of these compounds were determined from the correlation equation and the predictions for the lead optimization were described. The resulting QSAR revealed that the oxazolo(4,5-b)pyridine ring system with the substitution of a benzyl moiety at position 2 was the most favourable structure among the heterocyclic nuclei. Moreover, the fifth position in the fused ring system is found more significant than the other positions in improving the activity.
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