Green Chemistry Synthesis of Nanostructured Zinc Oxide Powder Using Azadirachta indica Extract for Latent Fingermark Development

@#Introduction: Application of nano-engineered fingerprint dusting powders has been a recent trend to achieve latent fingermark development with superior ridge clarity. As such, efforts have been made to utilise natural resources to increase the sustainability of these emerging nano-engineered powders. Lithium-doped zinc oxide, primarily used as white pigments, have been previously applied to latent fingermarks with success. In the current study, nanostructured zinc oxide, synthesised using neem extract as the reducing agent, was evaluated for fingermark development on non-porous surfaces. Methods: The reduction of zinc nitrate hexahydrate was facilitated by neem extract, prepared by boiling neem leaves in distilled water. The thick yellow paste recovered was calcined in the furnace to produce a light yellow powder. Physicochemical composition of the powder was determined using microscopic and spectroscopic instruments. The effectiveness of the powder was tested on natural fingermark deposited on several non-porous surfaces. Results: Nanostructured zinc oxide with particle size ranging in between 1 to 3 µm consisting of highly aggregated spherical particle with less than 100 nm dimensions were synthesised. Developed fingermarks revealed excellent ridge details and contrast on dark coloured surfaces. Studying the fingermark closely under scanning electron microscope displayed selective distribution of particle on the ridges of the fingermark residue and very minimal deposition on the fingermark valleys. Conclusion: Nanostructured zinc oxide fabricated using green chemistry approach can be applied for the development of fingermark. Nevertheless, future works can be undertaken to enhance particle dispersity and to confer strong photoluminescence to the zinc oxide nanoparticles.

Insecticidal activities and mechanism of extracts from neem leaves against Oxya chinensis / Atividade e mecanismos inseticidas de extratos de folhas "neem" contra Oxya chinesis

In this study, neem leaves were successively extracted with petroleum ether, 95% ethanol and water and the insecticidal activities of these extracts against Oxya chinensis larvae were measured. The results showed that 95% ethanol extract gave the highest extraction yield and insecticidal activity, and it was further extracted with five different solvents. The petroleum ether extract from the 95% ethanol extract possessed the highest insecticidal activity with median lethal concentration values ranging from 14.93 to 55.66mg/mL. The gas chromatography-mass spectrometer analysis showed that the petroleum ether extract mainly composed of alkanes, olefin, esters and amide. The pathological examination revealed that the prominent lesions, including reduced regenerative cells in midgut and swelled and degenerated cylindrical cells, were observed in the 5th instar Oxya chinensis after treatment. The ultrastructural features showed that the cylindrical cells, microvilli and mitochondria were seriously damaged. These results suggested that the petroleum ether extract from neem leaves had potent insecticidal activity and could be a candidate insecticide.(AU)

Nesse estudo, folhas "neem" foram extraídas com sucesso com éter de petróleo, 95% de etanol e água, e as atividades inseticidas desses extratos foram medidas contra larvas de Oxya chinesis. Os resultados mostram que extrato com 95% de etanol deram o maior resultado de extração e atividade inseticida e foi então extraído utilizando mais cinco diferentes solventes. O éter de petróleo do extrato de 95% etanol apresentou maior atividade inseticida com concentração letal média variando de 14.93 a 55.66mg/mL. A análise por cromatografia de massa mostrou que o extrato de éter de petróleo está composto principalmente de alcanos, alcenos, ésteres e amidas. A avaliação patológica revelou que as lesões proeminentes, inclusive células regenerativas reduzidas no intestino e células cilíndricas edemaciadas e degeneradas foram observadas no quinto estágio de desenvolvimento da Oxya chinesis após tratamento. As características ultraestruturais mostraram que as células cilíndricas, microvilos e mitocôndrias apresentavam lesões graves. Esses resultados sugerem que o extrato de éter de petróleo de folhas de "neem" tem atividade inseticida potente e pode ser um candidato a inseticida.(AU)

Preliminary Studies on Chemical Composition and Pharmacological Effects of Neem Leaves

Neem Leaves (Azadirachta indica A. Juss) collected in Binh Thuan province in May have been shown to contain alkaloids (0.66%), flavonoids (2.95), coumarins, reduced sugars and lipids. The alkaloid fraction gave 6 spots and the flavonoid fraction yielded 7 spots on this layer chromatography. Two substances, i.e., A6, an alkaloid and a flavonoid suspected to be Azadirachin A, have been isolated for further study. Liquid extract of Neem Leaves exerted anti-microbial activity against Staphylococcus aureus, Escherichia coli, Salmonella typhi, Pseudomonas aeruginosa and candida albicans