(E)-β-caryophyllene (BCP) is a natural sesquiterpene hydrocarbon present in hundreds of plant species. BCP possesses several important pharmacological activities, ranging from pain treatment to neurological and metabolic disorders. These are mainly due to its ability to interact with the cannabinoid receptor 2 (CB2) and the complete lack of interaction with the brain CB1. A systematic analysis of plant species with essential oils containing a BCP percentage > 10% provided almost 300 entries with species belonging to 51 families. The essential oils were found to be extracted from 13 plant parts and samples originated from 56 countries worldwide. Statistical analyses included the evaluation of variability in BCP% and yield% as well as the statistical linkage between families, plant parts and countries of origin by cluster analysis. Identified species were also grouped according to their presence in the Belfrit list. The survey evidences the importance of essential oil yield evaluation in support of the chemical analysis. The results provide a comprehensive picture of the species with the highest BCP and yield percentages.

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The phytochemical study of Cordia exaltata Lam. (Boraginaceae) led to the isolation, through chromatographic techniques, of nineteen secondary metabolites: 8,8'dimethyl-3,4,3',4'-dimethylenedioxy-7-oxo-2,7'cyclolignan (1), 8,8'-dimethyl-4,5-dimethoxy-3',4'-methylenodioxy-7-oxo-2,7'cyclolignan (2), sitosterol (3a), stigmasterol (3b), sitosterol-3-O-β-D-glucopyranoside (4a), stigmasterol-3-O-β-D-glucopyranoside (4b), phaeophytin A (5), 13²-hydroxyphaeophytin A (6), 17³-ethoxypheophorbide A (7), 13²-hydroxy-17³-ethoxypheophorbide A (8), m-methoxy-p-hydroxybenzaldehyde (9), (E)-7-(3,4-dihydroxyphenyl)-7-propenoic acid (10), 1-benzopyran-2-one (11), 7-hydroxy-1-benzopyran-2-one (12), 2,5-bis-(3',4'-methylenedioxiphenyl)-3,4-dimethyltetrahydrofuran (13), 3,4,5,3',5'-pentamethoxy-1'-allyl-8.O.4'-neolignan (14), 3,5,7,3',4'-pentahydroxyflavonol (15), 5,7-dihydroxy-4'-methoxyflavone (16), 5,8-dihydroxy-7,4'-dimethoxyflavone (17), kaempherol 3-O-β-D-glucosyl-6''-α-L-ramnopyranoside (18) and kaempherol 3,7-di-O-α-L-ramnopyranoside (19). Their structures were identified by ¹H and ¹³C-NMR using one and two-dimensional techniques. In addition, the antimicrobial activity of compounds 1, 2, 13 and 14 against bacteria and fungi are reported here for the first time.

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A series of twelve 2,5-bis(alkylamino)-1,4-benzoquinones were prepared in yields ranging from 9-58% via the reaction between p-benzoquinone and various amines. The structures of the synthesized compounds were confirmed by IR, 1H- and 13C-NMR and MS analyses. The phytotoxicity of the 2,5-bis(alkylamino)-1,4-benzoquinones was evaluated against two crop species, Cucumis sativus and Sorgum bicolor, at 1.0 x 10(-3) mol/L. In general, the quinones displayed inhibitory effects on the dicotyledonous species C. sativus (7-74%). On the other hand stimulatory effects were observed on S. bicolor (monocotyledonous). Similar results were observed in the biological assays carried out with the weed species Ipomoea grandifolia (dicotyledonous) and Brachiaria decumbens (monocotyledonous). In addition, the cytotoxicity of the 2,5-bis(alkylamino)-1,4-benzoquinones was assayed against HL-60 (leukemia), MDA-MB-435 (melanoma), SF-295 (brain) and HCT-8 (colon) human cancer cell lines and human peripheral blood mononuclear cells (PBMC), as representatives of healthy cells, using a MTT and an Alamar Blue assay. Compound 12 was the most active, displaying cytotoxicity against all cancer cell lines tested.

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(+)-Cordiaquinone J is a 1,4-naphthoquinone isolated from the roots of Cordia leucocephala that has antifungal and larvicidal effects. However, the cytotoxic effects of (+)-cordiaquinone J have never being explored. In the present study, the effect of (+)-cordiaquinone J on tumor cells viability was investigated, showing IC(50) values in the range of 2.7-6.6muM in HL-60 and SF-295 cells, respectively. Studies performed in HL-60 leukemia cells indicated that (+)-cordiaquinone J (1.5 and 3.0muM) reduces cell viability and 5-bromo-2-deoxyuridine incorporation after 24h of incubation. (+)-Cordiaquinone J showed rapid induction of apoptosis, as indicated by phosphatidylserine externalization, caspase activation, DNA fragmentation, morphologic changes, and rapid induction of necrosis, as indicated by the loss of membrane integrity and morphologic changes. (+)-Cordiaquinone J altered the redox potential of cells by inducing the depletion of reduced GSH intracellular content, the generation of reactive oxygen species and the loss of mitochondrial membrane potential. However, pre-treatment of cells with N-acetyl-l-cysteine abolished most of the observed effects related to (+)-cordiaquinone J treatment, including those involving apoptosis and necrosis induction.

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Background and aims Myrmecochory is a conspicuous feature of several sclerophyll ecosystems around the world but it has received little attention in the semi-arid areas of South America. This study addresses the importance of seed dispersal by ants in a 2500-km(2) area of the Caatinga ecosystem (north-east Brazil) and investigates ant-derived benefits to the plant through myrmecochory. Methods Seed manipulation and dispersal by ants was investigated during a 3-year period in the Xingó region. Both plant and ant assemblages involved in seed dispersal were described and ant behaviour was characterized. True myrmecochorous seeds of seven Euphorbiaceae species (i.e. elaiosome-bearing seeds) were used in experiments designed to: (1) quantify the rates of seed cleaning/removal and the influence of both seed size and elaiosome presence on seed removal; (2) identify the fate of seeds dispersed by ants; and (3) document the benefits of seed dispersal by ants in terms of seed germination and seedling growth. Key results Seed dispersal by ants involved one-quarter of the woody flora inhabiting the Xingó region, but true myrmecochory was restricted to 12.8 % of the woody plant species. Myrmecochorous seeds manipulated by ants faced high levels of seed removal (38-84 %) and 83 % of removed seeds were discarded on ant nests. Moreover, seed removal positively correlated with the presence of elaiosome, and elaiosome removal increased germination success by at least 30 %. Finally, some Euphorbiaceae species presented both increased germination and seedling growth on ant-nest soils. Conclusions Myrmecochory is a relevant seed dispersal mode in the Caatinga ecosystem, and is particularly frequent among Euphorbiaceae trees and shrubs. The fact that seeds reach micro-sites suitable for establishment (ant nests) supports the directed dispersal hypothesis as a possible force favouring myrmecochory in this ecosystem. Ecosystems with a high frequency of myrmecochorous plants appear not to be restricted to regions of nutrient-impoverished soil or to fire-prone regions.

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