The aim of this study was to investigate interactions between conventional antifungal drug and essential oils against isolates of Malassezia pachydermatis. Antifungal activity of Cinnamomum cassia, Melaleuca alternifolia, Mentha piperita, Origanum vulgare and Syzygium aromaticum essential oils were tested against 19 strains of M. pachydermatis isolated from healthy dogs and reference strain M. pachydermatis CBS 1879. The checkerboard assay was used to search for in- teractions. Synergism was observed for the combination of clotrimazole with Melaleuca alternifolia essential oil, Mentha piperita and Origanum vulgare. The combinations of Cinnamomum cassia and Syzygium aromaticum essential oils with clotrimazole showed indifferent effect. Additive antimicrobial activity was observed for the combination of clotrimazole with Syzygium aromaticum and Melaleuca alternifolia essential oils against reference strain. The obtained results showed synergistic interactions between essential oils and clotrimazole which could improve effectiveness of this antifungal drug.
The chemical composition of tea tree (Melaleuca alternifolia) and wintergreen (Gaultheria procumbens) essential oils as well as their phytotoxic effects against two invasive species – Cortaderia selloana and Nicotiana glauca – were studied. Fifty-eight compounds accounting for 98.89–99.94% of the total commercial tea tree and wintergreen essential oils were identified by Gas Chromatography-Mass Spectrometry (GC-MS) analysis. Tea tree essential oil with terpinen- 4-ol (28.37 ± 0.05%) followed by 1,8-cineole (15.81 ± 0.06%), γ-terpinene (15.60 ± 0.03%), α-pinene (10.92 ± 0.08%) and α-terpinene (8.52 ± 0.01%) as the main compounds did not produce significant effects against seed germination and hypocotyl growth of N. glauca, but showed significant effects in seed germination inhibition of C. selloana (34.69%) as well as in hypocotyl (60.96%) and radicle (62.55%) growth, at the highest dose (1 μl ⋅ ml–1) assayed. High amounts of methyl salicylate (99.63 ± 0.02%) were found in G. procumbens essential oil with remarkable phytotoxic effects in C. seollana. Methyl salicylate inhibited seed germination (77.38%) and hypocotyl and radicle growth (96.38% and 96.65%, respectively) at the highest dose (1 μl ⋅ ml–1) assayed. Wintergreen essential oil constitutes an eco-friendly alternative to control the high capacity of invasiveness of C. selloana.
In the study the comparative analysis of test results of drainage of municipal wastewater sludge was conducted with the use of flocculant Praestol 855BS and the mixture of flocculant Praestol 855BS 50% + orange essential oil 50%, as the reagents supporting this process. It was also attempted to reduce unpleasant smells exuding from the drained sludge. The process of drainage of municipal wastewater sludge was conducted in the laboratory setting centrifuge of MPW-350 type. The variable independent parameters were centrifugation time, centrifugation speed, dosage of flocculant Praestol 855BS as well as dosage of mixture in the proportion of flocculant Praestol 855BS (50%) + orange essential oil (50%). The following parameters were subject to assessment: water content in the sludge, dry mass content in the reflux as well as time of maintenance of the oil’s smell in the sludge. The conducted tests demonstrated that the orange essential oil has an impact on drop in resultant quality parameters of the drainage process of municipal wastewater sludge. Batching of the orange essential oil has an impact on considerable reduction of odours exuding from drained wastewater sludge, and thus on improvement of work conditions connected with operation of centrifugal separators. Bearing in mind both the efficient drainage process of wastewater sludge as well as simultaneous reduction of unpleasant smells exuding from the sludge during this process it is assumed and recommended to simultaneously apply both reagents, that is flocculant Praestol 855BS (50%) and orange essential oil, also in the volume of 50%.