Thymus daenensis, a perennial herb, is often grown in areas that experience drought conditions during its growing period. Application of chitosan may compensate for the negative impact of drought stress on the yield o...Thymus daenensis, a perennial herb, is often grown in areas that experience drought conditions during its growing period. Application of chitosan may compensate for the negative impact of drought stress on the yield of oil and secondary metabolites in Thymus.The interactive effects of foliar application of chitosan and drought stress on dry matter,essential oil yield, and selected physiological characteristics including photosynthetic pigments, osmotic adjustment, and lipid peroxidation of Thymus were investigated in a two-year study from 2014 to 2015. Treatments consisted of 0, 200, and 400(iL L'1 chitosan applied to plants grown under field capacity, mild drought stress(50% field capacity), and severe drought stress(25% field capacity). Dry matter yield decreased substantially as drought stress intensified. However, essential oil content increased under stress conditions,with the highest essential oil yield obtained from plants under mild drought stress. Foliar application of chitosan compensated to some extent for dry matter and oil yield reduction of plants grown under drought stress. The highest essential oil yield(1.52 g plant-1) was obtained by application of 400 \iL L_1 chitosan under the mild stress condition in 2015 when plants were mature. The compensatory effect of chitosan in reducing the negative impact of stress conditions on dry matter and oil yield was due mainly to stimulation of osmotic adjustment through proline accumulation and reduction of lipid peroxidase level, which increased the integrity of cell membranes of thyme leaves.展开更多
Cinnamon and lemon are the oldest plants which possess a rising popularity due to their therapeutic potential from centuries. Cinnamomum zeylanicum and lemon (Citrus lemon L.) have been subjected to extensive research...Cinnamon and lemon are the oldest plants which possess a rising popularity due to their therapeutic potential from centuries. Cinnamomum zeylanicum and lemon (Citrus lemon L.) have been subjected to extensive research. Their essential oils were extracted by steam distillation from selected plants and their chemical compositions were determined by the GC-MS system. Cinnamon and lemon essential oils were examined for antioxidant activity by ABTS method which showed the ability to inhibit lipid per-oxidation. On the other hand, in antimicrobial investigations, cinnamon and lemon essential oils have inhibitory effect against Gram positive bacteria (Staphylococcus aureus) and Gram negative bacteria (Escherichia coli) using Muller Hinton agar medium. The essential oils of cinnamon and lemon showed antifungal effects which were tested against (Candida albicans). The volatile oil of cinnamon bark has been found to be highly effective against all the tested bacteria and fungi. However, lemon peel essential oil has shown medium inhibition for Gram positive bacteria (Staphylococcus aureus). On the other hand, the cytotoxic activities of the essential oils were tested on hepatocellular carcinoma and colorectal carcinoma. Essential oils have shown good activities on the cell lines. Essential oil of cinnamon showed more inhibition rate than essential oil of lemon. This study reported the importance of both cinnamon and lemon volatile oils and recommends that cinnamon and lemon can be used as an active therapy for humans.展开更多
Antibacterial effect of cinnamon oil combined with thyme or clove oil was studied in this paper. Agar dilution method was used to determine the minimum inhibitory concentrations （MICs） of the essential oils （EOs） ...Antibacterial effect of cinnamon oil combined with thyme or clove oil was studied in this paper. Agar dilution method was used to determine the minimum inhibitory concentrations （MICs） of the essential oils （EOs） of cinnamon, thyme, and clove oil against three Gram-positive bacteria （Bacillus subtilis, Bacillus cereus, and Staphylococcus aureus）, and two Gramnegative bacteria （Escherichia coli and Salmonella typhimurium）. The results showed that cinnamon was a promising antibacterial substance with MIC ranged from 0.1 to 0.4 μL mL^-1 for the five bacterial species. Agar dilution checkerboard method was used to test the combined antibacterial effect of cinnamon oil with thyme or clove oil. Combination of cinnamon and thyme oil showed an additive effect against all selected bacteria, and combination of cinnamon and clove oil displayed an additive effect against B. subtilis, B. cereus, S. aureus, and an indifferent effect against E. coli and S. typhimurium. Furthermore, gas chromatography-mass spectrometry （GC-MS） measurement was used to analyze the components of the EOs, and the main components of cinnamon, thyme, and clove were cinnamaldehyde, thymol, carvacrol and p-cymene, and eugenol, respectively.展开更多
基金support from the University of Massachusetts Amherst
文摘Thymus daenensis, a perennial herb, is often grown in areas that experience drought conditions during its growing period. Application of chitosan may compensate for the negative impact of drought stress on the yield of oil and secondary metabolites in Thymus.The interactive effects of foliar application of chitosan and drought stress on dry matter,essential oil yield, and selected physiological characteristics including photosynthetic pigments, osmotic adjustment, and lipid peroxidation of Thymus were investigated in a two-year study from 2014 to 2015. Treatments consisted of 0, 200, and 400(iL L'1 chitosan applied to plants grown under field capacity, mild drought stress(50% field capacity), and severe drought stress(25% field capacity). Dry matter yield decreased substantially as drought stress intensified. However, essential oil content increased under stress conditions,with the highest essential oil yield obtained from plants under mild drought stress. Foliar application of chitosan compensated to some extent for dry matter and oil yield reduction of plants grown under drought stress. The highest essential oil yield(1.52 g plant-1) was obtained by application of 400 \iL L_1 chitosan under the mild stress condition in 2015 when plants were mature. The compensatory effect of chitosan in reducing the negative impact of stress conditions on dry matter and oil yield was due mainly to stimulation of osmotic adjustment through proline accumulation and reduction of lipid peroxidase level, which increased the integrity of cell membranes of thyme leaves.
文摘Cinnamon and lemon are the oldest plants which possess a rising popularity due to their therapeutic potential from centuries. Cinnamomum zeylanicum and lemon (Citrus lemon L.) have been subjected to extensive research. Their essential oils were extracted by steam distillation from selected plants and their chemical compositions were determined by the GC-MS system. Cinnamon and lemon essential oils were examined for antioxidant activity by ABTS method which showed the ability to inhibit lipid per-oxidation. On the other hand, in antimicrobial investigations, cinnamon and lemon essential oils have inhibitory effect against Gram positive bacteria (Staphylococcus aureus) and Gram negative bacteria (Escherichia coli) using Muller Hinton agar medium. The essential oils of cinnamon and lemon showed antifungal effects which were tested against (Candida albicans). The volatile oil of cinnamon bark has been found to be highly effective against all the tested bacteria and fungi. However, lemon peel essential oil has shown medium inhibition for Gram positive bacteria (Staphylococcus aureus). On the other hand, the cytotoxic activities of the essential oils were tested on hepatocellular carcinoma and colorectal carcinoma. Essential oils have shown good activities on the cell lines. Essential oil of cinnamon showed more inhibition rate than essential oil of lemon. This study reported the importance of both cinnamon and lemon volatile oils and recommends that cinnamon and lemon can be used as an active therapy for humans.
基金supported by the National High-Tech R&D Program of China (863 Program)(SQ2007AA10XK140105)the Zhejiang Province Key Scientific and Technological Project, China(2006C12051)the Zhejiang Provincial Center for Disease Control and Prevention (CDC) (Hangzhou,China)
文摘Antibacterial effect of cinnamon oil combined with thyme or clove oil was studied in this paper. Agar dilution method was used to determine the minimum inhibitory concentrations （MICs） of the essential oils （EOs） of cinnamon, thyme, and clove oil against three Gram-positive bacteria （Bacillus subtilis, Bacillus cereus, and Staphylococcus aureus）, and two Gramnegative bacteria （Escherichia coli and Salmonella typhimurium）. The results showed that cinnamon was a promising antibacterial substance with MIC ranged from 0.1 to 0.4 μL mL^-1 for the five bacterial species. Agar dilution checkerboard method was used to test the combined antibacterial effect of cinnamon oil with thyme or clove oil. Combination of cinnamon and thyme oil showed an additive effect against all selected bacteria, and combination of cinnamon and clove oil displayed an additive effect against B. subtilis, B. cereus, S. aureus, and an indifferent effect against E. coli and S. typhimurium. Furthermore, gas chromatography-mass spectrometry （GC-MS） measurement was used to analyze the components of the EOs, and the main components of cinnamon, thyme, and clove were cinnamaldehyde, thymol, carvacrol and p-cymene, and eugenol, respectively.
