RESUMO
The Spodoptera frugiperda is a notorious pest with a broad host range. It severely damages crops, mainly in areas of the globewhere maize and sorghum are grown. The pest is difficult to control due to its adaptive nature and resistance to several insecticides available in the market. So, an identification of the alternative strategy is the prime important in the present context. Insecticidal activities of cyanobacterial extracts were evaluated in the laboratory as a biocomponent against S. frugiperda. The crude extracts of Nostoc muscorum and Spirulina sp. were prepared by using ethanol, methanol and petroleum ether solvents. Soxhlet apparatus was used for extraction. S. frugiperda larvae in their second instar were given access to fragments of maize leaf that had been treated with various cyanobacterial extracts. The findings displayed that the petroleum ether extract of N. muscorum had the lowest LC50 value of 155.22 ppm, followed by petroleum ether extracts of Spirulina, ethanol extract of N. Muscorum, methanol extract of N. muscorum, ethanol and methanol extract of Spirulina with an LC50 values of 456.02, 710, 780, 1050 and 1070 ppm respectively. Later, the effect of LC50 values on many biological parameters like the larval duration and pupal stages, the percentage of pupation, the weight of the pupal stage, the malformation of the pupal and adult stages, adult emergence percentage, fertility and the longevity of the male and female adult stages of S. frugiperda was examined. The gas chromatography-mass spectrometry (GC-MS) was used to analyse the crude extract to identify the bioactive components that were responsible for the insecticidal properties. The major compounds detected were diethyl phthalate (19.87 %), tetradecane (5.03%), hexadecanoic acid, ethyl ester (4.10 %), dodecane (4.03%), octadecane (3.72%), octadecanoic acid, methyl ester (3.40 %), ethyl oleate (3.11 %), methyl ester. octadecenoic acid (3.04 %), heptadecane (3.04 %) and phytol (3.02 %). The presence of several bioactive chemicals in the cyanobacterial extracts may be the reason for their insecticidal actions, thus it can be used as an alternative and new source to combat fall armyworm and other crop pests.
RESUMO
This research study is to develop an easy and eco-friendly method for the synthesis of AgNPs using aqueous extract of endophytic fungi, Cladosporium species (CsAgNPs) and investigated the effects of antioxidant, anti-diabetic and anti-acetylcholinesterase (AChE), anti-butyrylcholinesterase (BChE) activity. Cladosporium species-mediated silver nanoparticles were characterized by UV-Vis spectrophotometer, Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and energy dispersive X-ray spectroscopy (EDX). The aqueous extract of Cladosporium species has shown the presence of carbohydrates, tannin, phenolic glycosides, terpenoids, alkaloids, phenol and anthraquinones. At 438 nm conformed the absorbance of AgNPs. The SEM result confirms that size, morphology and high density of the synthesized nanoparticles with huge disparity in the particle size distribution. The FTIR analysis confirmed the important biological compounds responsible for reduction of silver. Strong absorption property of AgNPs was studied by EDX. In antioxidant activity, CsAgNPs showed the involvement of NADPH-dependent reductase in the formation of AgNPs. The AgNPs has reduced the activity of α-amylase, α-glucosidase and dipeptidyl peptidase IV in vitro antidiabetic activity. The CsAgNPs showed significant glucose uptake in 3T3L1 cell line. The AgNPs have shown excellent inhibitory activity against AChE and BChE. To our best knowledge, this is the first on the synthesis of silver nanoparticles using endophytic fungi, Cladosporium species isolated from healthy leaf of Loranthus micranthus. Hence, to validate our results the in vivo animal studies at molecular level are needed to develop an antioxidant, anti-diabetic and anti-cholinesterase agent.
