Species of Aspidosperma are traditionally used to treat malaria, leishmaniasis, microbial, and inflammatory diseases. Aspidosperma subincanum Mart. known as "guatambu" is used in Brazilian traditional medicine to treat diabetes, hypercholesterolemia, and digestive diseases. Its tonic properties have been employed by the indigenous populations to stimulate the circulatory and genitourinary tracts and to improve respiratory function as well as to relieve spasms and to reduce fever. The species is known to contain antitumoural and antimalarial indole alkaloids. In the present study, various less explored biological activities of extracts from leaves and branches of A. subincanum were investigated, that is, inhibition of acetylcholinesterase as well as antioxidant and antibacterial activity. Twenty-one known indole alkaloids from this species were targeted for predicting the inhibition of acetylcholinesterase, and their biological activities were collected from the literature. Through in silico the prediction, the indole alkaloids uleine and derivatives demonstrated a strong probability of being able to inhibit the acetylcholinesterase enzyme, as well as the olivacine derivatives 3,4-dihydroolivacine and N-methyl-tetrahydro-olivacine (guatambuine), and the subincanadines C and E. Indeed, the extracts of A. subincanum showed acetylcholinesterase inhibitory activity, antioxidant activity in the lipid peroxidation assay, and antimicrobial activity against Staphylococcus aureus ATCC 25923, and their pharmacological properties should be explored further.

Ouratea spectabilis is an arborous species traditionally used in Brazil as an anti-inflammatory agent. Four new (3,3″)-linked biflavanone O-methyl ethers, named ouratein A (1), B (2), C (3), and D (4), were isolated from the bark extract of the species. Ouratein A ( 1) is an enantiomer of neochamagesmine A, which has never been described before. The structures were elucidated by extensive spectroscopic data analyses, whereas their absolute configurations were defined by electronic circular dichroism data. Ouratein D (4) inhibited in vitro the release of the pro-inflammatory cytokine CCL2 by lipopolysaccharide-stimulated THP-1 cells (IC 50 of 3.1 ± 1.1 μM), whereas TNF and IL-1β release were not reduced by any of the biflavanones. These findings show ouratein D (4) as a selective CCL2 inhibitor, which may have potential for the development of new anti-inflammatory agents to prevent or treat cardiovascular diseases.

This paper reports the in silico prediction of biological activities of lignans from Diphylleia cymosa and Podophyllum hexandrum combined with an in vitro bioassays. The extracts from the leaves, roots and rhizomes of both species were evaluated for their antibacterial, anticholinesterasic, antioxidant and cytotoxic activities. A group of 27 lignans was selected for biological activities prediction using the Active-IT system with 1987 ligand-based bioactivity models. The in silico approach was properly validated and several ethnopharmacological uses and known biological activities were confirmed, whilst others should be investigated for new drugs with potential clinical use. The extracts from roots of D. cymosa and from rhizomes and roots of P. hexandrum were very effective against Bacillus cereus and Staphylococcus aureus, while podophyllotoxin inhibited the growth of Staphylococcus aureus and Escherichia coli. D. cymosa leaves and roots showed anticholinesterasic and antioxidant activities, respectively. The evaluated extracts showed to be moderately toxic to THP-1 cells. The chromatographic characterization indicated that podophyllotoxin was the major constituent of P. hexandrum extract while kaempferol and its hexoside were the main constituents of D. cymosa leaves and roots, respectively. These results suggest that the podophyllotoxin could be the major antibacterial lignan, while flavonoids could be responsible for the antioxidant activity.

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