Ocimum gratissimum oil is used for various medicinal, food and cosmetic applications due to its high chemical variability. Local businesses have considered the economic exploitation of this plant. A specimen sampled at São Luís, MA, Brazil, with thymol and derivatives oil, was subjected to seasonal and circadian study, and to antifungal and antioxidant assays. It was possible to observe that the weather conditions showed a direct influence on the oil yield and variation of its constituents, mainly oxygenated monoterpenes and monoterpene hydrocarbons, with the predominance of thymol, γ-terpinene, and p-cymene. Principal component analysis (PCA) was able to justify the oil chemical variability of the seasonal (70%) and circadian (86%) study. Oil displayed inhibition for the fungus Corynespora cassiicola at a concentration above 0.3 µL mL-1, and it showed a more significant activity by comparison to thymol. Using 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical assay, the oil antioxidant activity was about 75% of thymol.

Ocotea duckei Vattimo é uma espécie nativa do nordeste brasileiro, conhecida popularmente como "Louro-de-cheiro". É rica em alcalóides, lignanas e óleos essenciais. Um dos constituintes mais importantes obtidos de Ocotea duckei é iangambina, uma lignana furorânica, que têm demonstrado várias atividades farmacológicas como: antagonista do receptor do fator de agregação plaquetária (PAF), efeito protetor contra colapso cardiovascular e choque anafilático, antialérgica, analgésica, anticonvulsivante e depressora do sistema nervosos central. O estudo morfo-anatômico das folhas de O. duckei foi realizado com o objetivo de contribuir com a sua identificação. O estudo morfológico foi realizado com auxílio de estereomicroscópio e através de observações de campo. O estudo anatômico foi feito a partir de cortes paradérmicos e transversais da folha (lâmina e pecíolo), descorados e corados com azul de astra e fucsina básica. As folha desta espécie são alternas, elípticas a oblongas, glabras, ápice agudo a acuminado e base aguda a ligeiramente atenuada. As características anatômicas principais são: epiderme uniestratificada, folha hipoestomática, com estômatos do tipo paracítico, mesofilo dorsiventral, presença de células secretoras no parênquima e feixes vasculares colaterias.

Ocotea duckei Vattimo is a plant native of Northeastern Brazil and popularly know as "Louro-de-cheiro". It is rich in alkaloids, lignans and essential oils. One of the most important constituents found in Ocotea duckei is yangambin, a furofuran lignan having significant pharmacological activities: as platelet activating factor (PAF) receptor antagonist, protective against cardiovascular collapse and anaphylactic shock, anti-allergic, analgesic, anti-convulsivant and as depressant of central nervous system. A morphoanatomical study of the leaves of O. duckei was carried out in order to contribute to separate its from the other species of the genus Ocotea, which would be helpful in its identification. The morphological study was done with stereomicroscope and by field observations. The anatomical studies were made by paradermic and transversal sections of leaves (blade and petiole), cleared and stained with Astrablue and basic Fuchsine. The leaves are alternate, leathery, elliptic to oblong, glabrous, acute to acuminate at the apex, and acute and lightly attenuate at the base. The main anatomical features are the epidermis unistratified, the hypostomatic leaves with stomata of the paracytic type, mesophyll is dorsiventral with secretories cells in the parenchyma and collateral vascular bundles.

Ocotea gardneri (Meisn.) Mez é uma espécie arbórea, encontrada no nordeste brasileiro, principalmente nos estados da Paraíba e Pernambuco, conhecida por "louro-branco" e "louro-babão". Neste trabalho realizou-se morfodiagnoses (macroscópica e microscópica) de folhas de O. gardneri, com o objetivo de fornecer subsídios à sua caracterização e identificação. Para a morfologia externa, analisaram-se amostras frescas e conservadas em álcool (70º), com auxílio de estereomicroscópio, e observações de campo. Realizaram-se secções transversais em lâminas foliares e pecíolos, e seções paradérmicas nas duas faces de lâminas foliares. Ocotea gardneri possui folhas elípticas a oval-elípticas, margem inteira, levemente ondeada, ápice agudo e base arredondada. A lâmina foliar é hipoestomática com estômatos do tipo paracítico; a epiderme é uniestratificada, com células de paredes retas e espessadas; o mesofilo é isobilateral, aqui referido pela primeira vez para uma espécie de Lauraceae, com células e ductos secretores evidentes e feixes vasculares colaterais envolvidos pela bainha esclerenquimática. Este conjunto de caracteres aliado à morfologia foliar, permitiram o estabelecimento de parâmetros que possibilitarão a caracterização de folhas de Ocotea gardneri em testes de autenticidade, bem como auxiliarão em estudos da taxonomia da espécie estudada.

Ocotea gardneri (Meisn.) Mez is a tree growing in the Northeast of Brazil and mainly found in the States of Paraiba and Pernambuco. It is known in the region as "louro-branco" and "louro-babão". This work was carried out with morphodiagnosis of leaves of O. gardneri for their characterization and identification. The study of external morphology was carried out with fresh and conserved (alcohol, 70º) samples with stereomicroscope complemented by field observations. Anatomical studies were done by transversal sections of leaves (blade and petiole), and paradermic sections in two surfaces of blades. The sections were clarified and stained with astrablue and basic fuchsine. The leaves of O. gardneri are elliptic to oval-elliptic, margin entire, slightly wavy, acute at the apex and rounded at the base. The blade leaf is hypostomatic with stomata of the paracytic type; the epidermis is unisseriate with cells of straight and thickened walls; the mesophyll is isobifacial, which is being related here for the first time for Lauraceae, with secretories cells and ducts and collateral vascular bundles involved by sclerenchymatic shealth. These features allowed the establishment of parameters for characterization of the leaves of Ocotea gardneri, as well as to the taxonomic studies on this species.