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Allelochemicals are considered an environment-friendly and promising alternative for weed management, although much effort is still needed for understanding their mode of action and then promoting their use in plant allelopathy management practices. Here, we report that Inuloxin A (InA), an allelochemical isolated from Dittrichia viscosa, inhibited root elongation and growth of seedlings of Lycopersicon esculentum and Lepidium sativum at the highest concentrations tested. InA-induced antioxidant responses in the seedlings were investigated by analysing the contents of glutathione (GSH) and ascorbate (ASC), and their oxidized forms, dehydroascorbate (DHA), and glutathione disulphide (GSSG), as well as the redox state of thiol-containing proteins. An increase in ASC, DHA, and GSH levels at high concentrations of InA, after 3 and 6 days, were observed. Moreover, the ASC/DHA + ASC and GSH/GSSG + GSH ratios showed a shift towards the oxidized form. Our study provides the first insight into how the cell redox system responds and adapts to InA phytotoxicity, providing a framework for further molecular studies.

The obligate ectoparasite Rhipicephalus (Boophilus) annulatus, also known as cattle tick, is the hard tick vector of babesiosis, a protozoal infection that causes severe meat production losses at huge economic costs. Although babesiosis was eradicated from the United States, its vector still exists in Mexico and different security measures are used to prevent its reintroduction into the U.S. Furthermore, the massive use of chemical acaricides during the last century has resulted in the development of resistance and toxicological problems. A possible and more sustainable alternative could be represented by the applications of biopesticides. Recently, two sesquiterpenoids, inuloxin A and α-costic acid isolated from Dittrichia viscosa, a perennial native plant of the Mediterranean basin, showed several interesting biological activities including acaricidal and antifeedant activities. Both inuloxin A and α-costic acid caused an impact on the hatch rate of the eggs and a larval mortality rate higher than 80% in vitro bioassays on eggs of R. annulatus. Moreover, the hatch rate of the eggs and the mortality rate of the larvae seem to be dependent on the timing of application of the compounds on the eggs. These results suggested a potential use of both compounds to control R. annulatus. [ABSTRACT FROM AUTHOR]

Allelochemicals are considered an environment-friendly and promising alternative for weed management, although much effort is still needed for understanding their mode of action and then promoting their use in plant allelopathy management practices. Here, we report that Inuloxin A (InA), an allelochemical isolated from Dittrichia viscosa, inhibited root elongation and growth of seedlings of Lycopersicon esculentum and Lepidium sativum at the highest concentrations tested. InA-induced antioxidant responses in the seedlings were investigated by analysing the contents of glutathione (GSH) and ascorbate (ASC), and their oxidized forms, dehydroascorbate (DHA), and glutathione disulphide (GSSG), as well as the redox state of thiol-containing proteins. An increase in ASC, DHA, and GSH levels at high concentrations of InA, after 3 and 6 days, were observed. Moreover, the ASC/DHA + ASC and GSH/GSSG + GSH ratios showed a shift towards the oxidized form. Our study provides the first insight into how the cell redox system responds and adapts to InA phytotoxicity, providing a framework for further molecular studies. [ABSTRACT FROM AUTHOR]

Primary amoebic meningoencephalitis (PAM), caused by the pathogenic free-living amoeba Naegleria fowleri , is a rare but fatal disease. Nowadays, no fully effective therapy is available to erradicate or prevent this disease. Natural products could constitute a promising source of useful bioactive compounds in drug discovery. The present study is a characterization of main active compounds from the ethanolic extract of Inula viscosa (Asteraceae) leaves against N. fowleri trophozoites. Four compounds ( 1 - 4 ) were successfully identified by spectroscopic techniques, but only inuloxin A displayed a potential antiamoebic activity with an IC 50 of 21.27 μM. The specificity of this compound toward the studied strain leads us to analyze the insight into its mechanism of action by performing in vitro assays of programmed cell death markers and to discuss the structure-activity relationship (SAR). The obtained results demonstrated that inuloxin A interferes with various processes leading to membrane damage, mitochondria alteration, chromatin condensation, and ROS accumulation, which highlight features specific to apoptosis. The current findings could be a promising step for developing new effective drugs against PAM.