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Polyphenols are secondary metabolites of plants and include a variety of chemical structures, from simple molecules such as phenolic acids to condensed tannins and highly polymerized compounds. Caffeic acid (3,4-dihydroxycinnamic acid) is one of the hydroxycinnamate metabolites more widely distributed in plant tissues. It is present in many food sources, including coffee drinks, blueberries, apples, and cider, and also in several medications of popular use, mainly those based on propolis. Its derivatives are also known to possess anti-inflammatory, antioxidant, antitumor, and antibacterial activities, and can contribute to the prevention of atherosclerosis and other cardiovascular diseases. This review is an overview of the available information about the chemical synthesis and antioxidant activity of caffeic acid derivatives. Considering the relevance of these compounds in human health, many of them have been the focus of reviews, taking as a center their obtaining from the plants. There are few revisions that compile the chemical synthesis methods, in this way, we consider that this review does an important contribution.

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Despite several reports point out a rhizosphere effect shaping soil microbial communities and others an effect of altitude on plant phenotypic features, currently little is known about the impact of elevational patterns on the diversity of soil microbial communities. In this study, diversity of soil microbial communities was assessed in samples derived of bulk and rhizosphere soils associated to Californian poppy (Eschscholzia californica Cham.) populations at 1000 and 2000 m.a.s.l in Central Chile. E. californica, a native plant of North America, is considered a successful invader in Mediterranean ecosystems worldwide but its effect on diversity of soil microbial communities is yet unknown. Microbial diversity was evaluated at genetic level through T-RFLP (terminal restriction fragment length polymorphisms) using bacterial, archaeal and fungal molecular markers, and at metabolic level using CLPP (community-level physiological profiles). At genetic level, microbial diversities of bulk and rhizosphere soils at lower altitude were similar, although at higher altitude microbial diversity of both types of soils was different, suggesting a plant filtering effect more notorious at higher altitude. At metabolic level, microbial diversity of rhizosphere soils were similar independently of the altitude, suggesting a plant filtering effect that exceeds the altitude effect observed in the case of the bulk soil.

The effects and consequences of global warming on the productivity of the Patagonian forest are still unknown. The use of Unmanned Aerial Vehicles (UAV) promotes new knowledge of the most pristine and unknown sub-antarctic forests located in Chilean Patagonia. This work presents an initial approach to spatialize biochemicals over the Patagonian forests using ultra-high spatial resolution imagery acquired from UAVs equipped with a multispectral (visible, near-infrared, and thermal) sensor. The images were obtained in multiple flights over the Cerro Castillo National Park (Aysén Region, Chile), and several Vegetation Indices (VIs) were estimated. Leaves of Nothofagus pumilio (Poepp. et Endl.) Krasser (Nothofagaceae) individuals were extracted after the flights and were then used to determine the biochemicals traits of chlorophylls (Chl-a and Chl-b) and carotenoids pigments, as well as the total phenolic content (TPC), total flavonoids content (TFC), and the DPPH radical scavenging assay. Their relationships with multiple VIs was analyzed in order to assess the spatiality of the biochemicals traits in the forest during it most productive phenological stage. Results showed high correlations for the biochemical traits pigments (R2 > 0.75) with the indices DVI, MCARI, and MSAVI1 as the best performing indices, while further spectral availability is needed for significant correlations with biochemicals traits related to the antioxidant capacity. Spatialization of the biochemical traits within UAV imagery was also performed evaluating their representation in the forest. This work allowed us to identify the different spectral behavior of the N. pumilio species, its relation to biochemical traits, and their spatialization, thus presenting the first step to developing a monitoring protocol for the evaluation of the Patagonian forests under the current global warming scenarios in the region.