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Abstract:The genus Mikania ranks high in the list of best-selling natural products in the world. Its main distribution is in South America, but some species are found in Asia, North America and Africa. It is used for treating fever, rheumatism, colds and respiratory diseases, as well as snake bites and scorpion stings, due to its broad spectrum of action. There are approximately 430 species of this genus and only 12% have been studied, highlighting their chemical and pharmacological diversity. The main chemical groups are: coumarins and derivatives, sesquiterpenes, sesquiterpenes lactones, diterpenes, phytosterols/terpenoids and flavonoids. This review aims to supply useful references for scientists interested in natural products and the search for new compounds, from over the 300 already described for the genus.

The present work aimed to analyze the alkaloid content of the ethanolic extract of Tabernaemontana catharinensis (Apocynaceae family) and its fractions as well as to evaluate their antioxidant and anticholinesterasic activities. The analyses of the ethanolic extract of T. catharinensis by mass spectrometry allowed identifying the presence of the alkaloids 16-epi-affinine, coronaridine-hydroxyindolenine, voachalotine, voacristine-hydroxyindolenine, and 12-methoxy-n-methyl-voachalotine, as well as an alkaloid with m/z 385.21 whose spectrum suggests a derivative of voacristine or voacangine. The extract and its alkaloid rich fractions showed antioxidant activity, especially those that contain the alkaloid m/z 385.21 or 16-epi-affinine with DPPH scavenging activity (IC50) between 37.18 and 74.69 μg/mL. Moreover, the extract and its fractions exhibited anticholinesterasic activity, particularly the fractions characterized by the presence of 12-methoxy-n-methyl-voachalotine, with IC50 = 2.1 to 2.5 μg/mL. Fractions with 16-epi-affinine combined good antioxidant (IC50 = 65.59 to 74.69 μg/mL) and anticholinesterasic (IC50 = 7.7 to 8.3 μg/mL) activities, representing an option for further studies aimed at treating neurodegenerative diseases.

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Lippia alba is a shrub found in all regions of Brazil and other countries in South and Central America. L. alba exhibits variability among its different accessions, showing differences in morphology and in the composition of its essential oil. This study evaluated the phenolic profiles and the antioxidant activities of seven different accessions of L. alba. The seven accessions of L. alba studied exhibited an important phenolic content, and all accessions demonstrated antioxidant activity with different efficacies. The main flavonoids in all accessions were apigenin, luteolin, naringin and rutin. The Santa Vitória do Palmar accession exhibited higher naringin and total phenolic content. This extract was able to reduce hydrogen peroxide-induced oxidative damage in tissue homogenates of cerebellum, cerebral cortex, hippocampus and liver of Wistar rats.

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