The interpretation of the distortions of the electron distribution in [2,2]cyclophanes (22-CPs) is controversial. Some studies indicate that there is an accumulation of electron density (ρ) outside the cavity of 22-CPs. The nature of through-space (ts) interaction is still under debate. The relative importance of ts and through-bond (tb) is an open question. In an attempt to clarify these points, we have investigated five 22-CPs and their corresponding toluene dimers by molecular orbitals analysis, electron density difference analysis, some topological analysis of ρ (quantum theory of atoms in molecules (QTAIM), electron localization function (ELF) and noncovalent interactions (NCI)), and energy decomposition analysis with natural orbitals for chemical valence (EDA-NOCV). ρ is concentrated inside the inter-ring region. All the analyses indicated that ts is predominant. The ts is composed by attractive dispersion and Pauli repulsion, with a small covalent contribution. Except for 1 and 6, all the compounds present inter-ring bond paths.

Copaifera species (Fabaceae) comprises approximately 70 species of large trees, from which 16 can be found in Brazil. The oleoresins obtained from their trunk are widely used in Brazilian folk medicine, which display important antitumoral potential. Chemically, these oleoresins are mainly composed of a mixture of sesquiterpenes and diterpenes. In this paper we are describing the isolation and identification of 12 already known terpenes from oleoresins obtained from three different Copaifera species (C. multijuga, C. pubiflora and C. trapezifolia) and 2 novel diterpenes (ent-16-hidroxy-3,13 clerodadien-15,18-dioic acid and ent-labda-5,13-dien-15-oic acid) from C. trapezifolia. Both new compounds were identified by nuclear magnetic resonance (NMR) spectroscopic (1H and 13C NMR, correlation 1H-1H (COSY), heteronuclear multiple quantum coherence (HMQC) and heteronuclear multiple bond correlation (HMBC)) and by high-resolution electrospray ionization mass spectrometry (HR-ESIMS) analyses. The cytotoxic potential of these oleoresins, their main non-volatile compounds and their volatile compound fractions were evaluated against a panel of tumoral (MCF-7, ACP01, A549, HeLa) and normal cell lines (MCF-10A, GM07492-A) through XTT (tetrazolium salt) and SRB (sulforhodamine B) assays. The novel diterpene ent-labda-5,13-dien-15-oic acid displayed relevant cytotoxic effect against most of the cancer cell lines with mean inhibitory concentration (IC50) values ranging from 3.57 ± 1.12 to 22.56 ± 1.03 µg mL-1, and a high selectivity level in both assays.

Lipoxygenase (LOX) plays an important role in inflammatory processes and Arrabidaea brachypoda (DC.) Bureau (Bignoniaceae) has been described as presenting anti-inflammatory activity. Therefore, the objective of this study was to develop a high-performance liquid chromatography (HPLC) procedure to directly recognize LOX inhibitor compounds in A. brachypoda crude extract, facilitating the isolation, characterization of bioactive compounds, evaluation of natural compounds using an in vitro 15-LOX assay and prediction of the most probable binding modes of their main constituent through molecular docking simulations. The chemical analysis was performed by ethanol crude extract microfractionation using HPLC-DAD (diode array detector) associated to a fraction collector. The bioactive chromatogram displayed a peak with 50.9% LOX inhibition at 13.6 min retention time. The extract was purified and conandroside was isolated, presenting a LOX inhibitory activity with an inhibitory concentration (IC50) of 7.8 ± 1.1 µM, close to standard quercetin (IC50 7.6 ± 0.3 µM). Additionally, conandroside was not cytotoxic to normal cells (GM07492A). The LOX-conandroside complex displayed a slightly higher docking score (92.7) than quercetin (71.5). These results together suggest that conandroside could be explored as lipoxygenase inhibitor.

Vochysia divergens (Vochysiaceae) is considered an invasive species in the wetlands of the Brazilian Pantanal, which hinders the cultivation of agricultural species. In this study, we evaluated the chemical profile by HPLC-DAD (high-performance liquid chromatography-diode array detector) of leaves extracts from V. divergens seedlings inoculated with endophytic fungi isolated from V. divergens roots. These fungi were collected on dry (D) and wet (W) seasons in the Pantanal. The presence of tannin hexahydroxydiphenoyl (HHDP)-galloyl-glucose and flavone 3',5'-dimethoxy-luteolin were predominant in the seedlings inoculated with endophytic fungi W experiments at 100 and 80%, respectively. Likewise, flavone 3',5-dimethoxy-luteolin-7-O-β-glucoside showed a similar representation in the two evaluated periods, compared with 5-methoxy-luteolin, which was detected only in seedlings inoculated with W endophytic fungi. This approach is new to V. divergens, which has no scientific data on its in vitro elicitation, in the search for a better understanding of the ecological relationships of this species.

In this work we present a complete proton (1H) and carbon 13 (13C) nuclear magnetic resonance (NMR) spectral analysis of two synthetic dihydrofuran neolignans (±)-trans-dehydrodicoumarate dimethyl ester and (±)-trans-dehydrodiferulate dimethyl ester. Unequivocal assignments were achieved by 1H NMR, proton decoupled 13C (13C{1H}) NMR spectra, gradient-selected correlation spectroscopy (gCOSY), J-resolved, gradient-selected heteronuclear multiple quantum coherence (gHMQC), gradient-selected heteronuclear multiple bond coherence (gHMBC) and nuclear Overhauser effect spectroscopy (NOESY) experiments. All hydrogen coupling constants were measured, clarifying all the hydrogen signals multiplicities. Computational methods were also used to simulate the 1H and 13C chemical shifts and showed good agreement with the trans configuration of the substituents at C7 and C8.