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RESUMO: "Capacidade antioxidante e atividade biológica do óleo essencial e extrato metanólico de Hyptis crenata Pohl ex Benth". O óleo essencial das folhas e ramos finos frescos e secos de Hyptis crenata forneceu os seguintes rendimentos, 1,4% e 0,9%. Os constituintes voláteis principais foram a-pineno (22,0%; 19,5%), 1,8-cineol (17,6%; 23,2%), b-pineno (17,0%: 13,8%), cânfora (4,7%; 11,6%), limoneno (5,4%; 4,4%) e g-terpineno (3,5%; 2,4%), totalizando mais de 70% nos óleos. A atividade de seqüestro do radical DPPH para o extrato metanólico (CE 50 , 16,7 ± 0,4 mg/mL) foi comparável ao do BHT (19,8 ± 0,5 mg/mL) mostrando uma significante atividade antioxidante. Os óleos apresentaram baixa atividade. O teor de fenólicos totais (TP, 373,0 ± 15,9 mg GAE/g) e equivalente trolox (TEAC, 226,8 ± 0,5 mg TE/g) confirmaram a atividade antioxidante do extrato metanólico, que pode ser atribuída à presença de compostos fenólicos polares. No teste com larvas de camarão as concentrações letais para o óleo e extrato metanólico foram 6,7 ± 0,2 mg/mL e 13,0 ± 3,7 mg/mL, respectivamente, fornecendo importante evidência de suas atividade biológicas.Unitermos: Hyptis crenata, Lamiaceae, "salva-do-marajó", óleo essencial, atividade antioxidante, teor de fenólicos totais, citotoxidade. ABSTRACT:The essential oils of fresh and dried leaves and fine stems of Hyptis crenata furnished the following yields: 1.4% and 0.9%. The main volatile constituents were a-pinene (22.0%; 19.5%), 1,8-cineole (17.6%; 23.2%), b-pinene (17.0%; 13.8%), camphor (4.7%; 11.6%), limonene (5.4%; 4.4%) and g-terpinene (3.5%; 2.4%), totalizing more than 70% in the oils. The DPPH radical scavenging activity (EC 50 , 16.7 ± 0.4 mg/mL) of the methanol extract was comparable to BHT (19.8 ± 0.5 mg/mL) showing a significant antioxidant activity. The oils showed low activities. The amount of total phenolics (TP, 373.0 ± 15.9 mg GAE/g) and trolox equivalent (TEAC, 226.8 ± 0.5 mg TE/g) confirmed the antioxidant activity of the methanol extract that can be attributed to the presence of polar phenolic compounds. In the brine shrimp bioassay the lethal concentrations (LC 50 ) for the oil and methanol extract were 6.7 ± 0.2 mg/mL and 13.0 ± 3.7 mg/mL, respectively, providing important evidence of their biological activities.

Os óleos essenciais das folhas, ramos finos, galhos, cascas do caule e frutos de Croton palanostigma foram analisados por CG e CG-EM. Os componentes principais determinados no óleo das folhas foram linalol (25,4%), (E)-cariofileno (21,0%), metileugenol (17,2%) e b-elemeno (6,0%); no óleo dos ramos finos foram a-pineno (41,4%), limoneno (29,0%), sabineno (11,5%) e b-pineno (5,7%); no óleo dos galhos foram metileugenol (24,1%), (E)-metilisoeugenol (15,3%), a-pineno (11,2%) e (E)-cariofileno (8,5%); no óleo das cascas do caule foram a-pineno (31,6%), metileugenol (25,6%) e (E)-metilisoeugenol (23,7%); e no óleo dos frutos foram linalol (42,7%), metileugenol (16,3%) e b-elemeno (6,4%). Análise estatística mostrou que as folhas e os frutos apresentam significante similaridade entre si, assim como os galhos e as cascas do caule. Adicionalmente, o óleo obtido das cascas do caule possui elevada atividade larvicida sobre Artemia salina (CL 50 , 3,71 ± 0,01 mg mL -1 ).The essential oils of leaves, twigs, branches, trunk bark and fruits of Croton palanostigma were analyzed by GC and GC-MS. The main compounds found in the oil of the leaves were linalool (25.4%), (E)-caryophyllene (21.0%), methyleugenol (17.2%) and b-elemene (6.0%); in the oil of the twigs were a-pinene (41.4%), limonene (29.0%), sabinene (11.5%) and b-pinene (5.7%); in the oil of the branches were methyleugenol (24.1%), (E)-methylisoeugenol (15.3%), a-pinene (11.2%) and (E)-caryophyllene (8.5%); in the oil of the trunk bark were a-pinene (31.6%), methyleugenol (25.6%) and (E)-methylisoeugenol (23.7%); and in the oil of the fruits were linalool (42.7%), methyleugenol (16.3%) and b-elemene (6.4%). Statistical analysis showed that the leaves and fruit, and the branches and trunk bark, have significant similarities between them. In addition, the trunk bark oil has high brine shrimp larvicidal activity (LC 50 , 3.71 ± 0.01 mg mL -1 ).

Abstract:The leaves and thin branches of Lippia grandis Schauer, Verbenaceae, are used for flavoring of food in the Brazilian Amazon, as substitute for oregano. In this study the constituents of the essential oil were identified and the antioxidant capacity and larvicidal activity of the oil and methanol extract and its sub-fractions were evaluated. A sensory evaluation was determined in view of absence of toxicity. The oil showed a yield of 2.1% and its main constituents were thymol (45.8%), p-cymene (14.3%), γ-terpinene (10.5%), carvacrol (9.9%) and thymol methyl ether (4.8%), totalizing 85%. The DPPH radical scavenging activity showed values for the EC50 between 9.0 and 130.5 µg mL -1 and the TEAC/ABTS values varied from 131.1 to 336.0 mg TE/g, indicating significant antioxidant activity for the plant. The total phenolic content ranged from 223.0 to 761.4 mg GAE/g, contributing to the antioxidant activity observed. The crude extracts inhibited the bleaching of β-carotene and the oil showed the greatest inhibition (42.5%). The oil (LgO, 7.6±2.4 µg mL -1 ) showed strong larvicidal activity against the brine shrimp bioassay. The sensory evaluation was highly satisfactory in comparison to oregano. The results are very promising for the use of L. grandis in seasoning and antioxidant products.

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