Dodecaborate anions of the type B₁₂X₁₂²⁻ and B₁₂X₁₁Y²⁻ (X=H, Cl, Br, I and Y=OH, SH, NH₃⁺, NR₃⁺) form strong (K_a up to 10⁶ L mol⁻¹, for B₁₂Br₁₂²⁻) inclusion complexes with γ‐cyclodextrin (γ‐CD). The micromolar affinities reached are the highest known for this native CD. The complexation exhibits highly negative enthalpies (up to −25 kcal mol⁻¹) and entropies (TΔS up to −18.4 kcal mol⁻¹, both for B₁₂I₁₂²⁻), which position these guests at the bottom end of the well‐known enthalpy‐entropy correlation for CDs. The high driving force can be traced back to a chaotropic effect, according to which chaotropic anions have an intrinsic affinity to hydrophobic cavities in aqueous solution. In line with this argument, salting‐in effects revealed dodecaborates as superchaotropic dianions.

In a new propolis type, red Brazilian propolis, 14 compounds were identified (six of them new for propolis), among them simple phenolics, triterepenoids, isoflavonoids, prenylated benzophenones and a naphthoquinone epoxide (isolated for the first time from a natural source). Three of the major components demonstrated significant antimicrobial activity, and two (obtained as inseparable mixture) possessed radical scavenging activity against 1,1‐diphenyl‐2‐picrylhydrazyl (DPPH).

Recently, the honey and propolis of stingless bees have been attracting growing attention because of their health-promoting properties. However, studies on these products of African Meliponini are still very scarce. In this preliminary study, we analyzed the chemical composition of honey, two cerumen, and two resin deposits (propolis) samples of Meliponula ferruginea from Tanzania. The honey of M. ferruginea was profiled by NMR and indicated different long-term stability from Apis mellifera European (Bulgarian) honey. It differed significantly in sugar and organic acids content and had a very high amount of the disaccharide trehalulose, known for its bioactivities. We suggested trehalulose to be a potential marker for African stingless bee honey analogously to the recent proposal for Meliponini honey from Asia, South America, and Australia and demonstrated its easy discrimination by ¹³C NMR. Propolis and cerumen were studied by GC-MS (gas chromatography-mass spectometry). The samples contained mainly terpenoids (di-and triterpenes) but demonstrated qualitative and quantitative differences. This fact was an indication that possibly M. ferruginea has no strict preferences for resins used to construct and protect their nests. The antimicrobial and anti-quorum sensing properties of the two materials were also tested. These first results demonstrated that the honey, cerumen, and propolis of African stingless bees were rich in biologically active substances and deserved further research.

Inclusion modes in complexes with α- and β-cyclodextrins in water have been investigated by NMR spectroscopy at 400 or 500 MHz, and compared with structures obtained by computer-aided molecular modelling and with calorimetric data. The NOEs observed on o- and m-aryl protons upon irradiation of either H3 or H5 inside the CD cavity indicate for all phenols an inclusion mode with the hydroxy group at the wide cavity end, and an increasingly deep immersion for phenol or phenolate with iodine compared with this nitro group, as para-substituent. This is found to be in line with the complexation-induced NMR shifts. Adamantane-1-carboxylate is indicated by distinct NOEs to be fully immersed into the β-CD cavity; the corresponding complex with α-CD shows contact only at the wider rim and a tilted conformation which allows formation of a hydrogen bond between the guest COO^– and the 2-OH group of the CD. The same conformation is found by CHARMm calculations, including simulations in a water box. The results, together with some ΔG^o values derived from NMR titrations, are in line with data from calorimetric studies. These show for complexes with tight fit (in α-CD) large enthalpies of up to 43 kJ mol^–1 as the predominating driving force against sizeable entropy disadvantages (TΔS^o⩽–24 kJ mol^–1), particularly for guest molecules of higher electron density and/or polarizibility. These observations point to predominating dispersive interactions. In contrast, inclusion in the wider β-CD cavity suffers less from entropy disadvantage (TΔS^o⩽–11 kJ mol-¹); the binding, however, is still dominated by ΔH^o, pointing to predominant cohesive and not entropic hydrophobic forces.