Mercury is among the ten most dangerous chemicals for public health, and is a priority concern for the 128 signatory countries of the Minamata Convention. Mercury emissions to the atmosphere increased 20% between 2010 and 2015, with South America, Sub-Saharan Africa and Southeast Asia as the main contributors. Approximately 80% of the total mercury emissions in South America is from the Amazon, where the presence of the metal is ubiquitous and highly dynamic. The presence of this metal is likely increasing, with global consequences, due to events of the last two years including extensive biomass burning and deforestation, as well as mining activities and the construction of large-scale projects, such as dams. Here we present a concise profile of this mobilization, highlighting the human exposure to this metal in areas without mining history. Mercury reaches the food chain in its most toxic form, methylmercury, intoxicating human populations through the intake of contaminated fish. Amazonian populations present levels over 6 ppm of hair mercury and, according to the 175:250:5:1 ratio for methylmercury intake : mercury hair : mercury brain : mercury blood, consume 2-6 times the internationally recognized reference doses. This exposure is alarmingly higher than that of other populations worldwide. A possible biphasic behavior of the mercury-related phenomena, with consequences that may not be observed in populations with lower levels, is hypothesized, supporting the need of improving our knowledge of this type of chronic exposure. It is urgent that we address this serious public health problem in the Amazon, especially considering that human exposure may be increasing in the near future. All actions in this region carry the potential to have global repercussions.

: Depression is a prevalent disease worldwide, limiting psychosocial functioning and thequality of life. Linalool is the main constituent of some essential oils from aromatic plants, representing about 70% of these volatile concentrates. Evidence of the linalool activity on the central nervous system, mainly acting as an antidepressant agent, is increasingly abundant. This review aimed to extend the knowledge of linalool's antidepressant action mechanisms, which is fundamental for future research, intending to highlight this natural compound as a new antidepressant phytomedication. A critical analysis is proposed here with probable hypotheses of the synergic mechanisms that support the evidence of antidepressant effects of the linalool. The literature search has been conducted in databases for published scientific articles before December 2020, using relevant keywords. Several pieces of evidence point to the anticonvulsant, sedative, and anxiolytic actions. In addition to these activities, other studies have revealed that linalool acts on the monoaminergic and neuroendocrine systems, inflammatory process, oxidative stress, and neurotrophic factors, such as BDNF, resulting in considerable advances in the knowledge of the etiology of depression. In this context, linalool emerges as a promising bioactive compound in the therapeutic arsenal, capable of interacting with numerous pathophysiological factors and acting on several targets. This review claims to contribute to future studies, highlighting the gaps in the linalool knowledge, such as its kinetics, doses, routes of administration, and multiple targets of interaction, to clarify its antidepressant activity.

The Piper genus is the most representative of the Piperaceae reaching around 2000 species distributed in the pantropical region. In the Neotropics, its species are represented by herbs, shrubs, and lianas, which are used in traditional medicine to prepare teas and infusions. Its essential oils (EOs) present high yield and are chemically constituted by complex mixtures or the predominance of main volatile constituents. The chemical composition of Piper EOs displays interspecific or intraspecific variations, according to the site of collection or seasonality. The main volatile compounds identified in Piper EOs are monoterpenes hydrocarbons, oxygenated monoterpenoids, sesquiterpene hydrocarbons, oxygenated sesquiterpenoids and large amounts of phenylpropanoids. In this review, we are reporting the biological potential of Piper EOs from the Neotropical region. There are many reports of Piper EOs as antimicrobial agents (fungi and bacteria), antiprotozoal (Leishmania spp., Plasmodium spp., and Trypanosoma spp.), acetylcholinesterase inhibitor, antinociceptive, anti-inflammatory and cytotoxic activity against different tumor cells lines (breast, leukemia, melanoma, gastric, among others). These studies can contribute to the rational and economic exploration of Piper species, once they have been identified as potent natural and alternative sources to treat human diseases.

The aromatic flora of the Amazon has been inventoried for 30 years. In this sense, were made over 500 field trips to collect over 2500 plants and to obtain more than 2000 essential oils and aroma concentrates, all of them submitted to GC and GC-MS. This work led to the creation of a database for the aromatic plants of the Amazon, which catalogs general information about 1250 specimens. The database has allowed the publication of the chemical composition of the oils and aromas of more than 350 species, associated with a larger number of chemical types. The essential oils of many species offer optimum conditions for economic exploitation and use in national and international market of fragrances, cosmetics, agricultural and household pesticides