Isolation of 1,4-naphthalenedione, an antibacterial principle from the leaves of Holoptelea integrifolia and its activity against β-lactam resistant Staphylococcus aureus.

Antimicrobials derived from plants have been receiving increasing attention in recent years. Antimicrobial activities of a number of phytochemicals have been reported. Many present day antibiotics are ineffective against several pathogenic organisms. About 90% of Staphylococcus aureus isolates from clinical specimens is reported to have resistance against β-lactam antibiotics. In the present study, the effect of hexane, diethyl ether, acetone and water extracts of leaves of a medicinal plant Holoptelea integrifolia has been tested against β-lactam resistant strain of S. aureus in presence of antibiotics such as ampicillin, amoxicillin, cefotaxime and ceftriaxone. The diethyl ether extract has shown the maximum antibacterial activity and the active principle is found to be 1,4-naphthalenedione which is characterized by GC-MS and FTIR spectroscopy. The minimum inhibitory concentration (MIC) of the compound is found to be 4 mg/ml. Structural similarity of this compound with a func- tional group of a β-lactamase-resistant antibiotic indicates that 1,4-naphthlenedione may be acting as an inhibitor to β-lactamase.

Morfo-anatomia do desenvolvimento de celtis iguanaea (jacq.) sarg. (ulmaceae) submetida ao alagamento e à submersão / Developmental morphology and anatomy of celtis iguanaea (jacq.) sarg. (ulmaceae) submitted to flooding and submersion

Celtis iguanaea es una especie pionera de la vegetación rebaliera. Las plantas de esta especie que ocurren en la planicie de inundación, con el eófilo completamente extendido, fueron sometidas a los siguientes tratamientos: capacidad de campo, anegadas por 25, 50 y 75 días y sumergidas por 25 y 50 días. Se constató que el anegamiento y la sumersión inhiben el crecimiento de las plantas causando una disminución de la materia seca de la parte aérea y la raíz. Plantas hundidas también presentaron abscisión foliar, degeneración del sistema radicular y un proceso precoz de senescencia. Después de 50 días de sumersión, todas las plantas murieron. Las plantas anegadas y sumergidas presentaron crecimiento secundario reducido de la raíz, hipocótilo y epicótilo. Las plantas anegadas por 75 días presentaron lenticelas y mayor número de pelos absorbentes. Los cotiledones y eófilo de las plantas anegadas y sumergidas no presentaron alteraciones anatómicas evidentes. El porcentaje de espacios intercelulares tampoco fue alterado. Celtis iguanaea, al presentar algunos caracteres que posiblemente se adapten a las condiciones de saturación hídrica del suelo, puede ser considerada como planta intolerante del anegamiento y la sumersión por un largo período.

Celtis iguanaea is a pioneer species of ciliary forest. In order to elucidate aspects of tolerance to the flooding andthe submersion, plants were submitted to the following treatments: field capacity, flooded for 25, 50 and 75 days and submerged by 25 and 50 days. It was verified that the flooding and the submersion inhibit the growth of the plants (decrease of the dry weight of the aerial part and root). Plants submerged also presented chlorosis, leaf abscission, degeneration of the root system and precocious senescence. After 50 days of submersion, all the plants died. Submerged and flooded plants presented reduced secondary growth of the root, hipocotyl and epicotyl. Flooded plants for 75 days presented lenticels and larger number of absorbent hairs. Cotyledons and eophylls of the flooded and submerged plants did not present evident anatomical alterations. Percentage of intercellular spaces in the root cortex was also not altered. Celtis iguanaea can be considered as intolerant plant to the flooding and the submersion, for long period.