Antibacterial and anti-inflammatory activities of an extract, fractions, and compounds isolated from Gochnatia pulchra aerial parts.

This paper reports on the in vitro antibacterial and in vivo anti-inflammatory properties of a hydroethanolic extract of the aerial parts of Gochnatia pulchra (HEGP). It also describes the antibacterial activity of HEGP fractions and of the isolated compounds genkwanin, scutellarin, apigenin, and 3,5-O-dicaffeoylquinic acid, as evaluated by a broth microdilution method. While HEGP and its fractions did not provide promising results, the isolated compounds exhibited pronounced antibacterial activity. The most sensitive microorganism was Streptococcus pyogenes, with minimum inhibitory concentration (MIC) values of 100, 50 and 25 µg/mL for genkwanin and the flavonoids apigenin and scutellarin, respectively. Genkwanin produced an MIC value of 25 µg/mL against Enterococcus faecalis. A paw edema model in rats and a pleurisy inflammation model in mice aided investigation of the anti-inflammatory effects of HEGP. This study also evaluated the ability of HEGP to modulate carrageenan-induced interleukin-1 beta (IL-1ß), tumor necrosis factor alpha (TNF-α), and monocyte chemoattractant protein-1 (MCP-1) production. Orally administered HEGP (250 and 500 mg/kg) inhibited carrageenan-induced paw edema. Regarding carrageenan-induced pleurisy, HEGP at 50, 100, and 250 mg/kg diminished leukocyte migration by 71.43%, 69.24%, and 73.34% (P<0.05), respectively. HEGP suppressed IL-1ß and MCP-1 production by 55% and 50% at 50 mg/kg (P<0.05) and 60% and 25% at 100 mg/kg (P<0.05), respectively. HEGP abated TNF-α production by macrophages by 6.6%, 33.3%, and 53.3% at 100, 250, and 500 mg/kg (P<0.05), respectively. HEGP probably exerts anti-inflammatory effects by inhibiting production of the pro-inflammatory cytokines TNF-α, IL-1ß, and MCP-1.

Analysis of insect cuticular compounds by non-lethal solid phase micro extraction with styrene-divinylbenzene copolymers.

Insect cuticular hydrocarbons including relatively non-volatile chemicals play important roles in cuticle protection and chemical communication. The conventional procedures for extracting cuticular compounds from insects require toxic solvents, or non-destructive techniques that do not allow storage of subsequent samples, such as the use of SPME fibers. In this study, we describe and tested a non-lethal process for extracting cuticular hydrocarbons with styrene-divinylbenzene copolymers, and illustrate the method with two species of bees and one species of beetle. The results demonstrate that these compounds can be efficiently trapped by Chromosorb® (SUPELCO) and that this method can be used as an alternative to existing methods.

The cuticular hydrocarbons profiles in the stingless bee Melipona marginata reflect task-related differences.

Members of social insect colonies employ a large variety of chemical signals during their life. Of these, cuticular hydrocarbons are of primary importance for social insects since they allow for the recognition of conspecifics, nestmates and even members of different castes. The objectives of this study were (1) to characterize the variation of the chemical profiles among workers of the stingless bee Melipona marginata, and (2) to investigate the dependence of the chemical profiles on the age and on the behavior of the studied individuals. The results showed that cuticular hydrocarbon profiles of workers were composed of alkanes, alkenes and alkadienes that varied quantitatively and qualitatively according to function of workers in the colony.

Cuticular hydrocarbons in the stingless bee Schwarziana quadripunctata (Hymenoptera, Apidae, Meliponini): differences between colonies, castes and age.

Chemical communication is of fundamental importance to maintain the integration of insect colonies. In honey bees, cuticular lipids differ in their composition between queens, workers and drones. Little is known, however, about cuticular hydrocarbons in stingless bees. We investigated chemical differences in cuticular hydrocarbons between different colonies, castes and individuals of different ages in Schwarziana quadripunctata. The epicuticle of the bees was extracted using the non-polar solvent hexane, and was analyzed by means of a gas chromatograph coupled with a mass spectrometer. The identified compounds were alkanes, branched-alkanes and alkenes with chains of 19 to 33 carbon atoms. Discriminant analyses showed clear differences between all the groups analyzed. There were significant differences between bees from different colonies, workers of different age and between workers and virgin queens.

Colony membership is reflected by variations in cuticular hydrocarbon profile in a Neotropical paper wasp, Polistes satan (Hymenoptera, Vespidae).

Nestmate recognition is one the most important features in social insect colonies. Although epicuticular lipids or cuticular hydrocarbons have both structural and defensive functions in insects, they also seem to be involved in several aspects of communication in wasps, bees and ants. We analyzed and described for the first time the cuticular hydrocarbons of a Neotropical paper wasp, Polistes satan, and found that variation in hydrocarbon profile was sufficiently strong to discriminate individuals according to their colony membership. Therefore, it seems that small differences in the proportion of these compounds can be detected and used as a chemical-based cue by nestmates to detect invaders and avoid usurpation.

Colony membership is reflected by variations in cuticular hydrocarbon profile in a Neotropical paper wasp, Polistes satan (Hymenoptera, Vespidae)

Nestmate recognition is one the most important features in social insect colonies. Although epicuticular lipids or cuticular hydrocarbons have both structural and defensive functions in insects, they also seem to be involved in several aspects of communication in wasps, bees and ants. We analyzed and described for the first time the cuticular hydrocarbons of a Neotropical paper wasp, Polistes satan, and found that variation in hydrocarbon profile was sufficiently strong to discriminate individuals according to their colony membership. Therefore, it seems that small differences in the proportion of these compounds can be detected and used as a chemical-based cue by nestmates to detect invaders and avoid usurpation.