We report for the first time the presence of cluster crystals of calcium oxalate within the glandular trichomes and oil bodies in the mesophyll for Baccharis species. Moreover, the comparative leaf anatomy and micro-morphology of six species of Baccharis, namely B. illinita, B. microdonta, B. pauciflosculosa, B. punctulata, B. reticularioides, and B. sphenophylla is investigated by light and scanning electron microscopy. The studied species exhibited differences in their leaf anatomical features such as the morphology of the cuticle, type and occurrence of the stomata, presence or absence of glandular trichomes, shape of the flagelliform trichomes, and the arrangement of the mesophyll tissues. These differences can be helpful in the species identification and classification and could represent informative characters for the reconstruction of the evolution of the genus.

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Lavandula dentata, popularly known as lavender, is commonly used in traditional medicine for the treatment of digestive and inflammatory disorders. The objective of this study was to analyzed the chemical oil composition, antioxidant and antimicrobial activities of the essential oil and anatomical markers of the leaf and stem of L. dentata cultivated in South Brazil. Essential oil showed an antioxidant activity similar to rutin and gallic acid when analyzed by phosphomolybdenum method. However, by the free radical DPPH and ABTS methods, it showed a slight potential antioxidant. Essential oil presented 1,8-cineol (63%) as major component, antimicrobial activity against Gram-positive, Gram-negative bacteria strains and Candida albicans, by broth microdilution. The anatomical profile provided the following main microscopic markers: hypostomatic leaves; diacytic stomata, thin and striate cuticle; multicellular and branched non-glandular trichomes; capitate glandular trichomes; peltate glandular trichomes; dorsiventral mesophyll; flat-convex shape midrib, truncated on the abaxial side; one collateral vascular bundle in the midrib; square stem shape, angular collenchyma alternated with cortical parenchyma; sclerenchymatic fibers well-developed on the four edges.

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Ocotea porosa (Nees & Mart.) Barroso, commonly known as "imbuia", "canela-imbuia" or "imbuiaamarela" in Brazil, is a tree of the Southern Atlantic Forest. The present study investigates the anatomy of leaf and stem, volatile oil chemistry, as well as cytotoxicity and insecticidal activities of the essential oil of O. porosa. Species identification was achieved by anatomy features, mainly due to paracytic and anomocytic stomata; non-glandular trichomes; biconvex midrib and petiole with a collateral open arc vascular bundle; presence of a sclerenchymatous layer, starch grains and crystal sand in the stem; and the presence of HIGHLIGHTS  The anatomy features were useful for identification of Ocotea porosa.  The major volatile compounds were α-pinene, β-pinene and bicyclogermacrene.  Essential oil of O. porosa was cytotoxic against McCoy, B16F10 and MCF7cell lines.  The cytotoxic mechanism might be related to apoptotic events.  Insert 1-4 highlights no longer than 85 characters.  Insert a highlight no longer than 85 characters.  Insert a highlight no longer than 85 characters. • Insert a highlight no longer than 85 characters.

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Some aromatic plants such as Thymbra capitata, Origanum vulgare, and Calamintha baetica are used in some Portuguese traditional meat dishes, particularly in rabbit meat, tomato salads, fish food, escargot, and olives. In the present work, the antioxidant ability of the essential oils extracted from T. capitata, O. vulgare, C. baetica, and Th. mastichina cultivated in a field of the Regional Direction of Agriculture of Algarve (Portugal) was studied. The oils, extracted by hydrodistillation, were analysed by gas chromatography and gaschromatography coupled to mass spectrometry. The antioxidant activity was determined using a modified thiobarbituric acid-reactive substances (TBARS) method, measuring the scavenging effect on 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical method, determining the reducing power method, and monitoring the chelating effect on ferrous ions method. The results showed that the oils from O. vulgare and T. capitata had practically the same capacity of preventing the lipid oxidation of those of BHT and BHA. T. capitata oil was the most effective for the scavenging effect on DPPH as any capacity for this effect was practically absent in the oils of Th. mastichina and C. baetica. These results can be explained by the relative high concentrations of phenol compounds in those plants. The essential oil isolated from C. baetica possessed the best ability of chelating ferrous ions, something practically inexistent in the remaining other plant samples and the BHT and BHA. The reducing power of the essential oils was much lower than those observed for the synthetic antioxidants, nevertheless among the oils, those from O. vulgare and T. capitata were the most effective. The chelating effect of the C. baetica oil can be used as a synergistic antioxidant, that is, this oil can be used together with a phenolic antioxidant in the food product, but at lower levels.