Chemical composition and antioxidant activity of the essential oil of Renealmia alpinia (Rottb.) Maas.

Renealmia alpinia (Rottb.) Maas was collected in Serra do Tepequém, municipality of Amajari, state of Roraima, Brazil. The essential oil was obtained from the fresh leaves by hydrodistillation using a Clevenger apparatus and analysed using GC-FID and GC-MS. The oil provided a yield of 0.6% (w/w), which, in the analysis of its contents, presented a higher concentration of sesquiterpenes, with α-phellandrene (23.10%), 16-oxo-8(17),12(E)-labdadien-15-oic acid (17.05%), ß-caryophyllene (10.28%), valencene (5.27%) and allo-aromadendrene (3.52%) being the most abundant. The antioxidant activity of the essential oil was determined using two methods, and indicated significant activity by both. Using the DPPH method, the essential oil presented an IC50 of 1.470 ± 0.0264 mg.L1 and an inhibition of the ß-carotene/linoleic acid oxidation system of 76.43 ± 0.80%.

Identification of lipophylic constituents of the nest of Frieseomelitta silvestrii (FRIESE, 1902).

Bees are becoming more and more valued for the extremely important role they play in ecological communities, especially for their pollinating action. The state of Roraima, Brazil has areas of native vegetation and variety of stingless bees, and this potential is still untapped. The objective of this study was to determine the chemical composition of materials collected from the nests of Frieseomelitta silvestrii (FRIESE, 1902), identified in São Luiz, in Roraima state, Brazil. The chemical composition of the collected material was determined by gas chromatography coupled to mass spectrometry (GC-MS). The dichloromethane extracts of propolis, cerumen threads and resin present in the stingless bee nest presented differentiated profiles with the occurrence of low polarity compounds.