The Ocotea genus exhibits a variety of pharmacological, antibacterial and antioxidant effects. The aim of the present study was to evaluate the antioxidant potential and antibacterial properties of the ethyl acetate fraction of Ocotea nutans leaves. Isolation and identification of the phenolic compounds from the fraction was also carried out. The isolated compounds were characterised by one- and two-dimensional nuclear magnetic resonance analysis and identified as vitexin (1) and isovitexin (2). The ethyl acetate fraction of Ocotea nutans leaves demonstrated considerable antioxidant potential. The observed minimum inhibitory concentration of 250 µg.mL⁻¹ was classified as a moderate antibacterial activity against Enterococcus faecalis. Findings from this study demonstrate the utility of this plant as a potential source of antioxidant and antibacterial agents. Graphical Abstract

In an effort to identify novel biopesticides, the present study aimed to assess the effects of Philodendron meridionale (Buturi & Sakur) stem and leaf ketonic and ethanolic extracts (SKE, SEE, LKE, and LEE, respectively) on the germination, growth, root respiration, and enzymatic activities of Lactuca sativa L. seeds, and to measure the associated saponins, phenolics, and flavonoids that may possess herbicidal, pharmaceutical, or pesticidal activities. The extracts were obtained using a modified Soxhlet apparatus and methanolic extracts of 0.1, 0.25, 0.5, 0.75 and 1.0 mg.mL-1 were tested, with water and methanol as a control. The presence of saponins and the concentration of phenolic compounds were determined. Allelopathic activity was evaluated in tests of germination, growth, cellular respiration and enzymatic activity. The presence of saponins and the concentration of phenolic compounds equivalent to 225.12 for LKE, 240.45 for LEE, 193.28 for SKE, and 265.14 for SEE (mg·g-1.gallic acid), and flavonoids 52.74 for LKE, 54.31 for LEE, 72.74 for SKE, and 67.21 for SEE (mg.g-1.quercetin) were determined. The allelopathy of the P. meridionale extracts against L. sativa was confirmed through negative effects on L. sativa seed germination, radical growth and morphology, dry mass, and the concentrations of α-amylase (EC 3.2.1.1), ascorbate peroxidase (EC 1.11.1.11), catalase (EC 1.11.1.6), and polyphenol oxidase (EC 1.10.3.1). It was likely that the allelopathic action of the P. meridionale extracts was related to its effects on the membrane permeability and oxidative stress of the treated L. sativa seeds. The P. meridionale extracts contained saponins, calcium oxalate crystals, and flavonoids, including phenolic compounds, which are known allelochemicals with herbicidal activities.

Panneerselvam et al.³ and Seetharaman et al.⁴ have reported that the overuse of conventional synthetic pesticides and larvicidal agents has influenced the emergence of resistant mosquito populations. The Brazilian flora, which is both extensive and diverse, is a natural asset possessing immense potential for secondary plant compounds, many of which can be utilized in the manufacture of agrochemicals. The search for novel compounds with larvicidal and insecticidal activities has gained further significance as the region is currently experiencing a dramatic increase in the incidence of insect-transmitted diseases.