Antimicrobial activity of dichloromethane and ethanol extracts and five compounds: pinostrobin (I), pinocembrin (II), tectochrysin (III), galangin 3-methyl ether (IV) and tiliroside (V) isolated from Lychnophora markgravii aerial parts against fifteen microorganisms was determined. The structures of these compounds were elucidated based on ESI-MS and NMR spectroscopic data. Both extracts showed antimicrobial activity against several tested microorganisms. Pinostrobin, tectochrysin and galangin 3methyl ether showed the strongest antibacterial and antifungal effects.

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The essential oils from leaves, twigs and trunk bark of Onychopetalum amazonicum R.E. Fr. (Annonaceae), obtained by hydrodistillation, were analysed by GC and GC-MS, and also were evaluated for in vitro antimicrobial activity. Forty-one compounds, which correspond to 75.0-92.2% of the oil components, were identified. Major compounds were sesquiterpenes, including (E)-caryophyllene, caryophyllene oxide, spathulenol, α-gurjunene, allo-aromadendrene and α-epi-cadinol. The oils were evaluated for antimicrobial activities against four bacteria strains and five pathogenic fungi. The oil of the trunk bark exhibited good activity against Staphylococcus epidermidis ATCC 12228, Escherichia coli ATCC 10538 and Kocuria rhizophila ATCC 9341, with a minimal inhibitory concentration of 62.5 μg/mL. The essential oil composition and the antimicrobial evaluation are reported for the first time for the genus Onychopetalum.

In this study, the antioxidant and cytotoxic activity, the phenolic content and the HPLC-DAD/ESI-MS profile of the ethanolic extracts of five Amaranthaceae plants collected in the south of Brazil were investigated: these were Alternanthera philoxeroides (Mart.) Griseb. (I), Alternanthera hirtula (Mart.) R.E. Fr. (II), Alternanthera praelonga A. St.-Hil. (III), Froelichia tomentosa (C. Mart.) Moq. (IV) and Pfaffia tuberosa (Spreng.) Hicken (V). The antioxidant potential was determined using the DPPH and ORAC-FL assays. The total phenolic content was measured using the Folin-Ciocalteu reagent. The ethanolic extracts of I, II, IV and V showed high levels of phenolic compounds (3.6-20.0 mg GAE/Kg), as well as high antioxidant activity in both methods. The cytotoxicity of the extracts was investigated in vitro against panel of human cancer cell lines and against VERO control. The extract of V exhibited anti-proliferative activity against all cancer cell lines studied (Total Growth Inhibition, TGI<100 µg/mL), except for VERO cell line (TGI=125.2 µg/ mL). HPLC-UV/DAD and ESI-MS analyses revealed that the extracts investigated appear to contain phenolic acids and flavonoids as main constituents. Findings from this study demonstrated that the extracts of the Amaranthaceae plants from the south of Brazil may be considered as promising sources of antioxidant and anti-proliferative compounds.

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