Antimicrobial and antioxidant activities of fennel oil.

It is of interest to estimate the effects of foliar spray (ISA) on essential oil yield, chemical constituents, antioxidant, and antimicrobial activities of fennel (Foeniculum vulgare Mill).Fennel was treated with ISA solutions at 40 and 80 mg L-1 doses. Application of ISA significantly augmented antioxidant and antimicrobial activities in addition to essential oil yield and its principal elements in fennel. 80 mg L-1 dose of ISA was found to be pre-eminent. Antioxidant properties of EOs were determined through DPPH assays, metal chelators and lipid peroxidation. While antimicrobial activities were evaluated using agar well diffusion and microdilution techniques of broth. Gram positive and Gram negative bacteria were used to gauge the oil's antibacterial effectiveness. Data shows that antioxidant and antimicrobial activities of fennel oil were found to be the highest. According to GC analysis, trans-anethole (78.38-86.08%), methyl chavicol (2.32-2.54%), and fenchone (6.65-8.95%) were the three main constituents of fennel essential oil.

Radiolytically depolymerized sodium alginate improves physiological activities, yield attributes and composition of essential oil of Eucalyptus citriodora Hook.

Eucalyptus citriodora Hook. is highly valued for its citronellal-rich essential oil (EO) extracted from its leaves. Hence, escalated EO production of eucalyptus is the need of hour. Marine polysaccharides (sodium alginate) are processed through gamma radiation of particular intensity, to obtain the irradiated sodium alginate (ISA). A pot experiment was conducted to study the effect of foliar application of ISA on growth, biochemical, physiological, EO yield and composition of E. citriodora. The treatments were applied as: foliar spray of deionized water only (control), seed soaked with ISA (90 mg L(-1)) and foliar spray of ISA with 30, 60, 120 and 240 mg L(-1). The treatment 6 (spray of ISA at 120 mg L(-1)) showed the highest value for most of the parameters studied. It also enhanced the EO content (33.3%), EO yield (86.7%), citronellal content (63.4%) and citronellal yield (205.5%) as compared to the control.

Depolymerized carrageenan ameliorates growth, physiological attributes, essential oil yield and active constituents of Foeniculum vulgare Mill.

Irradiated carrageenan (IC) elicits an array of plant defense responses and biological activities in plants. An experiment was carried out in the naturally illuminated conditions of net house in order to assess the effects of foliar spray of IC on agricultural performance of fennel (Foeniculum vulgare Mill.), which is a high-value essential oil bearing medicinal crop used in pharmaceutical, food and cosmetic industries. There were applied four IC concentrations (40, 60, 80 and 100 mg L(-1)) as foliar sprays. Application of IC significantly improved the growth attributes, physiological and biochemical parameters, essential oil yield and the contents of main components of essential oil of fennel. IC applied at 80 mg L(-1) enhanced these parameters maximally. Unirradiated carrageenan and deionized water had no effect on the attributes studied. Moreover, GLC analysis revealed a significant increase in the components of essential oil, viz. fenchone (4.48-7.82%) and anethole (78.38-86.08%) compared to the control.

Methyl jasmonate counteracts boron toxicity by preventing oxidative stress and regulating antioxidant enzyme activities and artemisinin biosynthesis in Artemisia annua L.

Boron is an essential plant micronutrient, but it is phytotoxic if present in excessive amounts in soil for certain plants such as Artemisia annua L. that contains artemisinin (an important antimalarial drug) in its areal parts. Artemisinin is a sesquiterpene lactone with an endoperoxide bridge. It is quite expensive compound because the only commercial source available is A. annua and the compound present in the plant is in very low concentration. Since A. annua is a major source of the antimalarial drug and B stress is a deadly threat to its cultivation, the present research was conducted to determine whether the exogenous application of methyl jasmonate (MeJA) could combat the ill effects of excessive B present in the soil. According to the results obtained, the B toxicity induced oxidative stress and reduced the stem height as well as fresh and dry masses of the plant remarkably. The excessive amounts of soil B also lowered the net photosynthetic rate, stomatal conductance, internal CO(2) concentration and total chlorophyll content in the leaves. In contrast, the foliar application of MeJA enhanced the growth and photosynthetic efficiency both in the stressed and non-stressed plants. The excessive B levels also increased the activities of antioxidant enzymes, such as catalase, peroxidase and superoxide dismutase. Endogenous H(2)O(2) and O(2)(-) levels were also high in the stressed plants. However, the MeJA application to the stressed plants reduced the amount of lipid peroxidation and stimulated the synthesis of antioxidant enzymes, enhancing the content and yield of artemisinin as well. Thus, it was concluded that MeJA might be utilized in mitigating the B toxicity and improving the content and yield of artemisinin in A. annua plant.