Bacterial infections cause thousands of deaths in the world every year. In most cases, infections are more serious because the patient is already weakened, and often, the bacteria are already resistant to the antibiotics used. Counterparting this negative scenario, the interest in medicinal plants as an alternative to the synthetic antimicrobial drugs is blossoming worldwide. In the present work, we identified the volatile compounds of ethanol extracts of Melissa officinalis, Mentha sp., Ocimum basilicum, Plectranthus barbatus, and Rosmarinus officinalis by gas chromatography/mass spectrometry (GC/MS). Also was evaluated antimicrobial activity of ethanol extracts against 6 bacteria of clinical interest, and was tested the interaction of these extracts with a commercial antibiotic streptomycin. Phytol was a compound identified in all extracts by GC/MS, being majoritary component in Plectranthus barbatus and Rosmarinus officinalis. The Gram-positive bacteria were more sensitive to ethanol extracts, and Plectranthus barbatus and Rosmarinus officinalis were the most active extracts. Ethanol extracts exhibited a synergetic effect with streptomycin. These results encourage additional studies, in order to evaluate the possibilities of using ethanol extracts of Lamiaceae family as natural source for antibacterial activity.

Decoction of roots of the Amazonian palm açaí (Euterpe precatoria Mart.) is widely used by Brazilian and Peruvian people as an anti-inflammatory, to heal kidney and liver diseases and against snake bites. In this study, the antioxidant activity of extracts and flavonoids (quercetin, catechin, epicatechin, rutin and astilbin) isolated from roots and leaf stalks of E. precatoria was investigated using β-carotene in TLC plates and DPPH radical scavenging in a spectrophotometric bioassay. All extracts and flavonoids showed activity. Also, the cytotoxic activity of these extracts was evaluated by the brine shrimp (Artemia salina) larvicide bioassay and was lower than that of lapachol, used as control. The presence of flavonoids and sitosterol-3-O-β-D-glucopyranoside in the extracts can justify the use of the plant in traditional medicine.