Volume 74, Issue 9-10 - Special Section: Chemistry of Social Insects / Special Section Editor: Wilhelm Boland

Primer pheromones play a pivotal role in the biology and social organization of insect societies. Despite their importance, they have been less studied because of the complexity of the required bioassays and, consequently, only a few of them have been chemically identified to date. The major primer pheromones are that of the queen pheromones that regulate reproductive skew and maintain colony cohesion and function. From a theoretical viewpoint, several features regarding the chemistry of queen pheromones can be predicted. They should be generally nonvolatile in order to avoid saturation of the colony space, which might otherwise hamper their perception because of sensory habituation. Accordingly, they should be actively dispersed throughout the colony by workers. The queen pheromone should also be caste-specific, qualitatively different from any worker pheromone, and preferably multicomponent, to allow unequivocal identification of the queen. The bi-potency of the female larvae in social Hymenoptera to become queen or worker necessitates strict regulation over pheromone production. Indeed, in the honeybee, the biosynthetic pathways as well as the genomic expressions are completely disparate between queens and workers. Future advances in chemical analyses, transcriptomics, proteomics, and metabolomics will enrich our understanding of the chemistry, mechanisms, and crucial role that primer pheromones play in social evolution.

Males of many bumblebee species exhibit a conspicuous pre-mating behavior with two distinct behavioral components: scent marking and patrol flying. The marking pheromone is produced by the cephalic part of the labial gland (CLG). As far as is known, the CLG secretion is species specific, and it usually consists of two types of compounds: (i) straight-chain aliphatic alcohols, aldehydes or esters, and (ii) acyclic mono-, sesqui- and diterpenes (alcohols or acetates). Here, we summarize data from the literature reporting chemical composition of the CLG secretions of more than 80 bumblebee species. Similarities and differences within and between subgenera are discussed in the context of biosynthetic pathways and evolution.

The queens of advanced social insects maintain their reproductive monopoly by using exocrine chemicals. The chemistry of these “queen pheromones” in termites is poorly known. We show that primary queens of four higher termites from the subfamily Syntermitinae ( Embiratermes neotenicus , Silvestritermes heyeri , Labiotermes labralis , and Cyrilliotermes angulariceps ) emit significant amounts of the sesquiterpene alcohol ( E )-nerolidol. It is the dominant analyte in queen body washes; it is present on the surface of eggs, but absent in kings, workers, and soldiers. In E. neotenicus , it is also produced by replacement neotenic queens, in quantities correlated with their fertility. Using newly synthesised (3 R ,6 E )-nerolidol, we demonstrate that the queens of this species produce only the ( R ) enantiomer. It is distributed over the surface of their abdomen, in internal tissues, and in the haemolymph, as well as in the headspace of the queens. Both ( R ) and ( S ) enantiomers are perceived by the antennae of E. neotenicus workers. The naturally occurring ( R ) enantiomer elicited a significantly larger antennal response, but it did not show any behavioural effect. In spite of technical difficulties encountered in long-term experiments with the studied species, (3 R ,6 E )-nerolidol remains among eventual candidates for the role in queen fertility signalling.

This study was performed to isolate antiobesity components from the crude extract of Portulaca oleracea . The crude extract was partitioned into n -hexane, 85% aqueous methanol, n -butanol, and water fractions. Their effects on adipogenic differentiation were evaluated in 3T3-L1 cells. Among the solvent fractions from P. olearacea , the 85% aq. MeOH effectively reduced the levels of lipid accumulation. Further purification of 85% aq. MeOH led to the isolation of the known homoisoflavonoids 1–4 , as the active substances. The administration of homoisoflavonoids to adipocyte cells decreased the lipid accumulation and glucose consumption and increased the release of glycerol into culture medium. In particular, homoisoflavonoid 3 effectively down-regulated the adipogenic transcription genes such as peroxisome proliferator activated receptor-γ ( PPARγ ) and CCAAT/enhancer-binding proteins ( C/EBP α), and adipogenic target genes such as fatty acid binding protein 4 ( FABP4 ), fatty acid transport protein 1 ( FATP1 ), and acyl-CoA synthase 1 ( ACS1 ).

A new compound, integracid ( 1 ), together with four known compounds were isolated from the dichloromethane (CH 2 Cl 2 ) extract from Artemisia integrifolia L. The structures of compounds ( 1–5 ) were elucidated by spectroscopic methods, including ultraviolet, infrared (IR), high resolution-electrospray ionization-mass spectrometry (HR-ESI-MS) and extensive one-dimensional (1D) and two-dimensional (2D) nuclear magnetic resonance (NMR) techniques, and by comparison with data reported in the references. Antibacterial activities of the compounds were evaluated against various bacteria.

Overexpression of aromatase in breast cancer cells may substantially influence its progression and maintenance. In this sense, the inhibition of aromatase is a key target for the treatment of breast cancer in postmenopausal women. Although several flavonoids had already demonstrated the capacity of inhibiting aromatase activity, the role of biflavonoids as aromatase inhibitors is poorly studied. In this work, the biflavonoids isolated from Garcinia gardneriana , morelloflavone ( 1 ), Gb-2a ( 2 ) and Gb-2a-7- O -glucose ( 3 ) were submitted to in vitro assay to evaluate the aromatase modulatory effect. As results, it was demonstrated that all biflavonoids were able to inhibit the enzyme, with IC 50 values ranging from 1.35 to 7.67 μM. This demonstrates that biflavonoids are an important source of scaffolds for the development of new aromatase inhibitors, focusing on the development of new anticancer agents.