Percorrer por autor "Santos, Nuno"
A mostrar 1 - 3 de 3
Resultados por página
Opções de ordenação
- Chemistry, bioactivities, extraction and analysis of azadirachtin: State-of-the-artPublication . Fernandes, Sara; Barreiros, Luisa; Ferraz Oliveira, Rita; Cruz, Agostinho; Prudêncio, Cristina; Oliveira, Ana Isabel; Pinho, Cláudia; Santos, Nuno; Morgado, JoaquimAzadirachta indica A. Juss. (Neem) is an Indian tree recognized for its activity as pesticide, as well as several pharmacological properties. Among the various compounds already isolated and studied from Neem tree, azadirachtin (AZA) was identified as the main bioactive compound. Azadirachtin can be found at different parts of the Neem plant but assumes its maximum concentration at the seed level. This compound features a quite complex chemical structure, which justifies the 20-plus-year difficulty to identify the synthetic pathway that subsequently permitted to carry out its artificial synthesis. Azadirachtin is widely used as a basis for production of biopesticides; nevertheless, other properties have been recognized for this substance, among which the anticancer and antimalarial activity stand out. The methods available for azadirachtin extraction are diverse, including solid-liquid extraction and extraction with solvents at high or low temperatures. Alcohol based solvents are associated with higher extraction yields and are therefore preferred for the isolation of azadirachtin from plant parts. Clean-up of the extracts is generally required for further purification. The highest azadirachtin levels have been obtained from Neem seeds but concentration values present a large variation between batches. Therefore, in addition to extraction procedures, it is essential to establish routine methods for azadirachtin identification and quantification. Chromatography-based techniques are preferably selected for detection and quantification of azadirachtin in plant matrices. Overall, this process will guarantee a future reproducible, safe and effective use of the extracts in formulations for commercial applications.
- Determination of Azadirachtin in Neem oil from different origins by HPLC-DADPublication . Fernandes, Sara; Barreiros, Luisa; Ferraz Oliveira, Rita; Prudêncio, Cristina; Vieira, Mónica; Santos, Nuno; Morgado, Joaquim; Cruz, AgostinhoNeem (Azadirachta indica) is an Indian tree recognized for its activity as pesticide, as well as several pharmacological properties. Among the compounds isolated from Neem, Azadirachtin (AZA) was identified as the main bioactive compound. AZA assumes its maximum concentration at seeds, portion which is used as the primary source to obtain the Neem oil.
- Evaluation of antimicrobial activity in products containing Neem oilPublication . Fernandes, Sara; Barreiros, Luisa; Ferraz Oliveira, Rita; Prudêncio, Cristina; Vieira, Mónica; Santos, Nuno; Morgado, Joaquim; Cruz, AgostinhoNeem oil is obtained from seeds of Azadirachta indica, which present 30 to 50% (w/w) of oil per seed. Neem oil has been associated with a great diversity of beneficial properties, namely antimicrobial, anti-inflammatory and insecticide. Information concerning the antibacterial activity of Neem oil is scarce. Although the existing studies have demonstrated activity against both Gram+ and Gram- bacteria, the results are in some cases contradictory and do not include a significant number of organisms, namely organisms associated with skin infections.