Antioxidant approach to disease management and the role of ‘Rasayana’ herbs of Ayurveda

Antibacterial screening of some Peruvian medicinal plants used in Callería District

Bioactivities of Piper aduncum L. and Piper obliquum Ruiz & Pavon (Piperaceae) essential oils from Eastern Ecuador.

The essential oils of the specimens of Piper aduncum that occur in deforested areas of Brazilian Amazon, North Brazil, are rich in dillapiole (35-90%), a derivative of phenylpropene, to which are attributed biological properties. On the other hand, the oils of the specimens with occurrence in the Atlantic Forest, and Northeastern and Southeastern Brazil, do not contain dillapiole, but only terpene compounds such as (E)-nerolidol and linalool. One specimen existing in the Amazon was hydrodistilled. The obtained oil was fractioned on a silica chromatographic column, resulting in fractions rich in dillapiole (95.0-98.9%) utilized for analyses by GC and GC/MS, structural characterization by NMR, confirmation of their biological properties, and to obtain the isomer isodillapiole. Dillapiole showed a fungicide action against the fungus Clinipellis perniciosa (witches' broom) by inhibition of its basidiospores, in concentrations ranging from 0.6 to 1.0 ppm. The larvicide and insecticide actions of dillapiole were tested against the larvae and the adult insects of Anopheles marajoara and Aedes aegypti (malaria and dengue mosquitoes), resulting in mortality of the larvae (48 h, 100%) at a concentration of 100 ppm, and mortality of the insects (30 min, 100%) at a concentration of 600 ppm. The isomeric isodillapiole showed no significant activity in the same biological tests.

Chemical variation in Piper aduncum and biological properties of its dillapiole-rich essential oil.

The chemical composition of essential oil of leaves of Piper aduncum L., growing wild in a fragment of the Atlantic Rainforest biome in northeastern Brazil, was determined through gas chromatography-mass spectrometry. The acaricidal activity and repellency of the essential oil and its components [dillapiole (0.28 g/ml), α-humulene (0.016 g/ml), (E)-nerolidol (0.0007 g/ml) and β-caryophyllene (0.0021 g/ml)] were evaluated in the laboratory against adults of Tetranychus urticae Koch. The mites were more susceptible to the oil in fumigation tests (LC50 = 0.01 μl/l of air) than in contact test with closed Petri dish (LC50 = 7.17 μl/ml); mortality was reduced by approximately 50 % in the latter test. The repellent action of the oil and toxicity by fumigation and contact did not differ significantly from the positive control (eugenol). The repellent activity was attributed to the components (E)-nerolidol, α-humulene and β-caryophyllene, whereas toxicity by fumigation and contact was attributed to β-caryophyllene. The effect of Piper oil and the role of its components regarding host plant preference with a two-choice leaf disk test are also discussed.

Acaricidal activity and repellency of essential oil from Piper aduncum and its components against Tetranychus urticae

The essential oils of eight samples of Piper aduncum L., collected at different localities of the Amazon region, were analysed by GC–MS. The major component identified in all samples was dillapiole (31.5–97.3%). Sample A, collected at Serra do Navio (AP), showed a yield of oil and dillapiole content of 3.3% and 31.5%, respectively; sample B, collected at Melgaco (PA), 1.8% and 50.8%; sample C, collected at Benfica (PA), 1.6% and 56.3%; samples D and E, collected at Belem (PA), 1.2% and 82.2%; 1.5% and 86.9%, respectively; sample F, collected at Manaus (AM), 3.4% and 91.1%; sample G, collected at Road Manaus-Caracarai, km 30 (AM), 3.0% and 97.3%; sample H, collected at Cruzeiro do Sul (AC), 3.2% and 88.1%. The yield of oil and dillapiole content of samples of P. aduncum occurring in Malaysia and Fiji showed 1.3% and 64.5%; and 0.5% and 58.0%, respectively. By comparison, the plants growing wild in Amazonas State had the highest oil yield and dillapiole content. © 1998 John Wiley & Sons, Ltd.

Maria Das Graças B. Zohhbi

Papers

Constituents of the essential oil of Piper aduncum L. growing wild in the Amazon region