Myrcia hatschbachii D. Legrand (Myrtaceae) is a native and endemic species from Brazil. This study investigated the essential oil composition, phytotoxic potential, in vitro toxicity, antioxidant properties and antibacterial activity of species. Chromatographic analysis of essential oil identified trans-calamanene, (E)-caryophyllene and spathulenol as major components. Antioxidant capacity was determined by the DPPH• scavenging method and phosphomolybdenum complex formation assay. Antibacterial activity was evaluated using the Minimal Inhibitory Concentration test, demonstrating that the essential oil was active toward Enterococcus faecalis and Staphylococcus aureus. Phytotoxic activity of essential oil was analyzed by testing interference on germination and growth of Lactuca sativa, demonstrating significant inhibition of the hypocotyls and radicles of seeds. Preliminary toxicity studies were determined using Artemia salina, resulting in an LC 50 of 409.92 µg/mL, and through hemolytic activity. The results of the phytotoxic activity point to a possible application for Myrcia hatschbachii in the development of natural herbicides and the in vitro toxicity assays suggests the performance of antitumoral activity tests, having in mind the prospection of antineoplastic drugs.

The article has aimed to characterize the essential oil extracted from Ocotea diospyrifolia (Meisn.) Mez. leaves, in terms of its chemical composition and antioxidant, hemolytic, and phytotoxic potentials, as well as its toxicity against Artemia salina. The major constituents identified by CG-MS were δ-elemene, spathulenol, and β-atlantol. When screened for potential biological activities, the essential oil presented low toxicity against Artemia salina, and a capacity of lysing red blood cells. Also, the evaluation of its in vitro antioxidant activity, using the phosphomolybdenum method, showed better results when compared to butylhydroxytoluene (BHT) and rutin. In conclusion, the results obtained showed certain in vitro toxicity, leading to an interesting target for cytotoxicity evaluations of carcinoma cells.

The genus Myrcia is used in folk medicine to treat diabetes. The plants used in folk medicine require morphological and anatomical references to attest to its authenticity. This is the first report of the microscopic study of Myrcia hatschbachii. In this sense, the aim of the present study was to describe the anatomical characteristics, in order to contribute to the species' identification. For anatomical and surface analyses free-hand sections were prepared and observed using optical microscopy, simultaneously some materials were processed and observed under scanning electron microscopy. In addition, histochemical tests were performed. The anatomical features described here correspond with previously reported features found in other species of the genus Myrcia. Furthermore, the following anatomical markers were observed in Myrcia hatschbachii: druses in the spongy parenchyma, concave-convex midrib, heart-shaped petiole, oval-shaped stem, C-shaped vascular bundle in the midrib and open arc shape with invaginated ends in the petiole; phenolic compounds in the phloem and lignified cells in the pith. The results of anatomical and histochemical analyses provide micromorphological and microchemical features that can help in the taxonomy and proper identification of the species.