Laguncularia racemosa leaves indicate the presence of potentially toxic elements in mangroves.

Brazilian mangroves have been severely impacted by metallurgical, petrochemical, pyrometallurgical smelters and other industrial activities. In Rio de Janeiro, mangroves are part of the Atlantic Rainforest now under the stress of high levels of industrial waste. Therefore, this work aimed to detect potentially toxic elements (PTEs) by evaluating the leaves of Laguncularia racemosa (L.) Gaertn. f. collected from three mangroves with different levels of pollution. To gain further insight toward an accurate diagnosis of the effects of anthropogenic pollution on mangrove stands, we evaluated leaf epicuticular wax composition, as well as morphological and anatomical traits. Samples were analyzed using inductively coupled plasma-optical emission spectroscopy (ICP-OES), gas chromatography (GC) and microscopy. Results revealed variation in the contents of PTEs among the three mangroves from lowest to highest concentration, as follows: Al (0.30-0.73), Pb (0.095-0.325) and Zn (0.25-0.30) mg/kg. Zn was detected in sclerenchyma tissues. Leaf epicuticular wax contained more than 50% of triterpenes, in particular, the pentacyclic triterpenes lupeol (41.61-55.63%) and ß-amyrin (8.81-16.35%). Such high concentrations promote the increase in leaf permeability to salts and PTEs. Micromorphology of leaf epicuticular wax in L. racemosa also varied among the three evaluated sites, especially around stomatal openings, but no harmful changes were noted. L. racemosa plays a key role in the rich diversity of mangrove ecosystems. As such, this species could, by the presence of PTEs in its leaves, be a suitable biomonitor of toxic substances in coastal environments of the world and used accordingly in strategies designed for eco-sustainable technologies.

Determination of the Phytochemical Composition and Antioxidant Potential of Eugenia copacabanensis and Myrciaria tenella Leaves (Myrtaceae) Using a Saccharomyces cerevisiae Model.

Eugenia copacabanensis and Myrciaria tenella are present in restingas of the Atlantic Forest, but little information is available about their chemical and biological potential. In this context, the hexane, dichloromethane, ethyl acetate and butanol fractions from the leaves of methanolic extract were analyzed by GC/MS and HPLC-DAD and the antioxidant potential was determined by DPPH and ABTS assays and using a Saccharomyces cerevisiae model. Dereplication allowed the identification of 68 compounds, 42 and 41 of which, respectively, are first reported here for E. copacabanensis and M. tenella. In vivo results revealed that the ethyl acetate and butanol fractions showed expressive antioxidant protection in the BY4741 and Δgsh1 strains, with greater impact on glutathione-deficient cells. With a high diversity of phenolic compounds, these polar fractions of E. copacabanensis and M. tenella leaves are potential protectors against intracellular oxidative stress.

The presence of heavy metals in Avicennia schaueriana Stapf & Leechman ex Moldenke leaf and epicuticular wax from different mangroves around Sepetiba Bay, Rio de Janeiro, Brazil.

This study aimed to investigate the leaf epicuticular wax and the presence of heavy metals in leaves of Avicennia shaueriana, a halophyte found in Brazilian mangroves. We evaluated plants collected in mangroves located around Sepetiba Bay, Rio de Janeiro State. Heavy metals were analyzed by energy dispersive X-ray spectroscopy (EDS or EDX) and inductively coupled plasma optical emission spectrometry (ICP-OES). Chemical analysis of epicuticular wax was made by gas chromatography-mass spectrometry (GC-MS). We also evaluated the micromorphology of leaf surface using scanning electronic and light microscopy. The leaves from each mangrove presented alterations in wax layer. Fagarasterol (lupeol) in high quantity was the main triterpene identified in the leaf wax from plants collected in all mangroves: Coroa Grande (76.43%), Pedra de Guaratiba (38.91%), and Marambaia (62.56%). Al, Fe, Mn, and Zn were the main heavy metals detected in leaves from the three mangroves by ICP-OES. Thus, we show that that plants able to survive in the mangrove swamp can adapt to the exposure of heavy metals, accumulate them in their leaves, and be used in coastal area recovery projects as a phytoremediator.

Chemical characterization of Myrciaria floribunda (H. West ex Willd) fruit.

M. floribunda fruit was studied to characterize its chemical composition. The chemical composition, bioactive compounds, antioxidant activity and volatiles of the fruit were determined. The chemical composition was determined according to AOAC and AOCS, the bioactive compounds by HPLC, the volatiles by GCMS and the antioxidant activity by ABTS+ and DPPH methods. The chemical composition of the freeze-dried fruit was 1.89 g·100 g-1, 2.43 g·100 g-1, 4.78 g·100 g-1 and 90.89 g·100 g-1 of ashes, lipids, proteins and total carbohydrates on a dry base, respectively. The concentration of the carotenoids was 52.22 mg·100 g-1 and for the flavonoid rutin was 78.56 mg·100 g-1. The gallic and ellagic acid contents were 5.45 mg·g-1 and 2.21 mg·g-1, respectively. The cis-ß-ocimene corresponded to 50.90% of the volatiles. The antioxidant activity by ABTS+ method was 550.14 µmol Trolox·g-1 and by the DPPH method the EC50 was 85.68 g·g-1. The fruits presented relevant antioxidant activity, a high concentration of carotenoids and of rutin.