This work describes the tissue culture of Plectranthus ornatus Codd. (Lamiaceae) on Murashige and Skoog (MS) medium with naphthalene acetic acid (NAA) (1.0, 2.0 and 4.0 mg L-1) and 6-benzylaminopurine (BAP) (1.0, 2.0 and 4.0 mg L-1) as growth regulators to obtain the overproduction of rosmarinic acid. The content of rosmarinic acid and its biosynthetic precursors were determined by high performance liquid chromatography (HPLC). The antioxidant activities (AA) of the extracts were also evaluated by 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay. The best growing condition was observed with the addition of 1.0 mg L-1 of both NAA and BAP in the culture medium yielded an increase of 94 times of rosmarinic acid comparing with the wild plant. All extracts diplayed antioxidant activity, as evidenced by the DPPH free radical scavenging assay. However, those with 2.0 mg L-1 NAA and, 1.0 mg L-1 NAA and BAP in culture medium showed the lowest EC50 (26.0 and 29.8 µg mL-1, respectively). At concentration higher than 10 µg mL-1 of rosmarinic acid it was not observed the correlation with AA, suggesting some other anti-oxidant mechanism acting.

<p>Phytochemical investigation of the MeOH extract of Schinopsis brasiliensis Engl. stems led to the isolation of the new biflavanone (2R*,3R*,2''R*,3''R*)-7-hydroxy-4'-methoxy-flavanone- (3→3'')-3''',7''-dihydroxy-4'''-methoxy-flavanone and 4,2',4'-trihydroxychalcone-(3→O→4'')- 2''',4'''-dihydroxychalcone, whereas methyl gallate, gallic acid, (6R,9R)-megastigma-4-en-3-one- 9-O-β-glucopyranoside, quercetin-3-O-β-D-xylopyranoside and tricetin-3'-O-β-D-glucopyranoside were isolated from the MeOH extract of leaves. Their chemical structures were elucidated using spectroscopic methods and comparison with the literature data. Both biflavonoids showed weak inhibition activities of acetyl and butyrylcholinesterase enzymes when compared with eserine.</p>

Polygalaceae is represented in Brazil by ten genera and 191 species, of which the Polygala is the most representative, characterized by the occurrence of methyl salicylate. Seventeen species of Polygalaceae have been analyzed by HPLC-DAD and the technique proved to be selective, precise, accurate, and with low limits of quantification and detection. The analysis of plant material confirmed the presence of methyl salicylate, with concentration values ranging from 14.1 a 126.9 µg/g.

This work describes the evaluation of the antioxidant activity in the system b-carotene / linoleic acid and radical scavenging effects of the substances epicatechin-(2β→7,4β→8)-epicatechin, epicatechin, epigalocatechin-(2β→7,4β→8)-epicatechin, luteolin 3-β-Dglicopiranoside and crisoeriol 7-β-D-glicopiranoside isolated of the extract AcOEt of the stem of Dioclea lasiophylla, in comparison with the standards n-propyl gallate, BHT and a-tocopherol.