TBS-pyrrole as an "universal" reference to quantify artemisinin and structurally-diverse natural products in plants extracts by NMR.

The commercial production of artemisinin and other valuable bioactive natural products depends on their plant sources, which may provide variable amounts of the compound depending on plant variety, the period of the year, abiotic stress and other factors. Therefore, it requires a method for large-scale, low-cost natural product quantification. The standard HPLC and UHPLC methods are accurate but the analysis are costly and require different optimization for structurally-diverse products. An alternative method using NMR with TBS-pyrrole as a novel "universal" reference affords a simple, fast method to quantify many different products. The method is shown with antimalarial artemisinin, whose yield using conventional and novel extraction procedures was determined by standard UHPLC-MS procedures and by our NMR protocol, with similar quantification results. The novel reference compound does not interfere with artemisinin or extract signals, only needs a small amount of the extract, is accurate and operationally simple, and a large volume of samples can be processed in little time. Moreover, bioactive terpenes, steroids, alkaloids, aromatic compounds, and quinones, among others, were quantified in a model vegetal extract with this "universal" reference with excellent accuracy.

The use of chitosan oligosaccharide to improve artemisinin yield in well-watered and drought-stressed plants.

Introduction: Artemisinin is a secondary metabolite well-known for its use in the treatment of malaria. It also displays other antimicrobial activities which further increase its interest. At present, Artemisia annua is the sole commercial source of the substance, and its production is limited, leading to a global deficit in supply. Furthermore, the cultivation of A. annua is being threatened by climate change. Specifically, drought stress is a major concern for plant development and productivity, but, on the other hand, moderate stress levels can elicit the production of secondary metabolites, with a putative synergistic interaction with elicitors such as chitosan oligosaccharides (COS). Therefore, the development of strategies to increase yield has prompted much interest. With this aim, the effects on artemisinin production under drought stress and treatment with COS, as well as physiological changes in A. annua plants are presented in this study. Methods: Plants were separated into two groups, well-watered (WW) and drought-stressed (DS) plants, and in each group, four concentrations of COS were applied (0, 50,100 and 200 mg•L-1). Afterwards, water stress was imposed by withholding irrigation for 9 days. Results: Therefore, when A. annua was well watered, COS did not improve plant growth, and the upregulation of antioxidant enzymes hindered the production of artemisinin. On the other hand, during drought stress, COS treatment did not alleviate the decline in growth at any concentration tested. However, higher doses improved the water status since leaf water potential (YL) improved by 50.64% and relative water content (RWC) by 33.84% compared to DS plants without COS treatment. Moreover, the combination of COS and drought stress caused damage to the plant's antioxidant enzyme defence, particularly APX and GR, and reduced the amount of phenols and flavonoids. This resulted in increased ROS production and enhanced artemisinin content by 34.40% in DS plants treated with 200 mg•L-1 COS, compared to control plants. Conclusion: These findings underscore the critical role of ROS in artemisinin biosynthesis and suggest that COS treatment may boost artemisinin yield in crop production, even under drought conditions.

Root treatment with a vitamin K3 derivative: a promising alternative to synthetic fungicides against Botrytis cinerea in tomato plants.

BACKGROUND: Botrytis cinerea, the causal agent of gray mold has a great economic impact on several important crops. This necrotrophic fungus causes disease symptoms during vegetative growth and also into postharvest stages. The current method to combat this disease is fungicide application, with high economic costs and environmentally unsustainable impacts. Moreover, there is an increasing general public health concern about these strategies of crop protection. We studied the protection of tomato plants against B. cinerea by previous root treatment with menadione sodium bisulfite (MSB), a known plant defense activator. RESULTS: Root treatment 48 h before inoculation with MSB 0.6 mmol L-1 reduced leaf lesion diameter by 30% and notably cell deaths, compared to control plants 72 h after inoculation. We studied the expression level of several pathogenesis-related (PR) genes from different defense transduction pathways, and found that MSB primes higher PR1 expression against B. cinerea. However, this stronger induced resistance was impaired in transgenic salicylic acid-deficient NahG line. Additionally, in the absence of pathogen challenge, MSB increased tomato plant growth by 28% after 10 days. Our data provide evidence that MSB protects tomato plants against B. cinerea by priming defense responses through the salicylic acid (SA)-dependent signaling pathway and reducing oxidative stress. CONCLUSION: This work confirms the efficacy of MSB as plant defense activator against B. cinerea and presents a novel alternative to combat gray mold in important crops.

A Beginner's Guide to Osmoprotection by Biostimulants.

Water is indispensable for the life of any organism on Earth. Consequently, osmotic stress due to salinity and drought is the greatest threat to crop productivity. Ongoing climate change includes rising temperatures and less precipitation over large areas of the planet. This is leading to increased vulnerability to the drought conditions that habitually threaten food security in many countries. Such a scenario poses a daunting challenge for scientists: the search for innovative solutions to save water and cultivate under water deficit. A search for formulations including biostimulants capable of improving tolerance to this stress is a promising specific approach. This review updates the most recent state of the art in the field.

Pure Organic Active Compounds Against Abiotic Stress: A Biostimulant Overview.

Biostimulants (BSs) are probably one of the most promising alternatives nowadays to cope with yield losses caused by plant stress, which are intensified by climate change. Biostimulants comprise many different compounds with positive effects on plants, excluding pesticides and chemical fertilisers. Usually mixtures such as lixiviates from proteins or algal extracts have been used, but currently companies are interested in more specific compounds that are capable of increasing tolerance against abiotic stress. Individual application of a pure active compound offers researchers the opportunity to better standarise formulations, learn more about the plant defence process itself and assist the agrochemical industry in the development of new products. This review attempts to summarise the state of the art regarding various families of organic compounds and their mode/mechanism of action as BSs, and how they can help maximise agricultural yields under stress conditions aggravated by climate change.

Evaluación de diferentes regímenes terapéuticos empleados en el tratamiento de la giardiasis en niños / Evaluation of different therapeutic regimens used in the treatment of giardiasis in children

Se realizó un estudio experimental en los consultorios 15, 16, 17 y 18 correspondientes al área de salud del Policlínico Gaspar con el objetivo de evaluar la respuesta a diferentes regímenes terapéuticos en el período comprendido desde junio del 2007 al 2008. La muestra estuvo comprendida por 200 pacientes con edades comprendidas entre 0 y 14 años con complementarios de heces fecales directos o seriados positivos de giardiasis y sin tratamiento anterior. Los pacientes fueron distribuidos de forma aleatoria a cada uno de los grupos de tratamiento garantizando la homogeneidad de la muestra. Al finalizar el tratamiento se realizó la evaluación final en relación con los síntomas clínicos y los resultados de heces fecales. El grupo de edades comprendida entre 10 a 14 años y el sexo femenino predominaron en el universo de pacientes estudiados, el dolor abdominal y las diarreas fueron los síntomas más frecuentemente encontrados, estos desaparecieron en más de la mitad de los niños que fueron tratados con tinidazol y metronidazol. Los mejores resultados en el análisis de las heces fecales después de culminado el tratamiento correspondieron a los grupos tratados con estos dos medicamentos.

An experimental study was conducted in 15, 16, 17 and 18 clinics for the health area of Gaspar Polyclinic in order to evaluate the response to different treatment regimens from June 2007 to 2008. The sample consisted of 200 patients aged between 0 and 14 years with fecal specimens or positive serial of giardiasis and without prior treatment. Patients were randomly assigned to each of the treatment groups by ensuring the homogeneity sample. After treatment the final evaluation was conducted in relation to clinical symptoms and fecal specimens’ results. The age group between 10 and 14 years and female predominance in the studied group of patients, abdominal pain and diarrhea were the most frequently found symptoms; they disappeared in more than half of children who were treated with tinidazole and metronidazole. The best results in the analysis of feces after the treatment completion corresponded to the groups treated with these two drugs.