Acaricidal activity of synthesized titanium dioxide nanoparticles using Calotropis gigantea against Rhipicephalus microplus and Haemaphysalis bispinosa

OBJECTIVE@#To assess the acaricidal activity of titanium dioxide nanoparticles (TiO2 NPs) synthesized from flower aqueous extract of Calotropis gigantea(C. gigantea) against the larvae of Rhipicephalus (Boophilus) microplus [R. (B.) microplus] and the adult of Haemaphysalis bispinosa (H. bispinosa).@*METHODS@#The lyophilized C. gigantea flower aqueous extract of 50 mg was added with 100 mL of TiO(OH)2 (10 mM) and magnetically stirred for 6 h. Synthesized TiO2 NPs were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Scanning electron microscopy (SEM), and Energy dispersive X-ray spectroscopy (EDX). The synthesised TiO2 NPs were tested against the larvae of R. (B.) microplus and adult of H. bispinosa were exposed to filter paper impregnated method.@*RESULTS@#XRD confirmed the crystalline nature of the nanoparticles with the mean size of 10.52 nm. The functional groups for synthesized TiO2 NPs were 1 405.19, and 1 053.45 cm(-1) for -NH2 bending, primary amines and amides and 1 053.84 and 1 078.45 cm(-1) for C-O. SEM micrographs of the synthesized TiO2 NPs showed the aggregated and spherical in shape. The maximum efficacy was observed in the aqueous flower extract of C. gigantea and synthesized TiO2 NPs against R. (B.) microplus (LC50=24.63 and 5.43 mg/L and r(2)=0.960 and 0.988) and against H. bispinosa (LC50= 35.22 and 9.15 mg/L and r(2) = 0.969 and 0.969), respectively.@*CONCLUSIONS@#The synthesized TiO2 NPs were highly stable and had significant acaricidal activity against the larvae of R. (B.) microplus and adult of H. bispinosa. This study provides the first report of synthesized TiO2 NPs and possessed excellent anti-parasitic activity.

Antioxidant activity of newly discovered lineage of marine actinobacteria

OBJECTIVE@#To investigate the antioxidant activity of marine actinobacteria.@*METHODS@#The content of total phenolics, the level of antioxidant potential by DPPH radical scavenging activity, metal chelating activity, FRAP method, β carotene assay and NO scavenging activity in extract were determined.@*RESULTS@#In all the methods the extract exhibited good scavenging activity except NO scavenging activity. The IC(50) values of marine actinobacteria extract on DPPH radical were found to be 41.09 μg/mL. The zone of color retention was 12 mm in β-carotene bleaching assay. DNA protective efficiency of the extracts was also studied using UV-photolysed H(2)O(2)-driven oxidative damage to pBR322. HPLC analysis identified some of the major phenolic compounds in extracts, which might be responsible for the antioxidant potential and cyto-protection. It showed a 100% cytotoxic effect in brine shrimp lethality assay within 10 mins. The novel actinobacteria was identified as Streptomyces LK-3 (JF710608) through 16S rDNA Sequencing.@*CONCLUSIONS@#The results obtained suggest that the extracts bear anti-cancer metabolites and could be considered as a potential source for anti-cancer drug development.

Phytochemical composition and in vitro antioxidant activity of aqueous extract of Aerva lanata (L.) Juss. ex Schult. Stem (Amaranthaceae)

OBJECTIVE@#To analyze the phytochemical composition and in vitro antioxidant properties of aqueous extract of Aerva lanata (A. lanata) stem.@*METHODS@#During the preliminary phytochemical analysis, the aqueous extract of A. lanata was screened for the presence of carbohydrates, proteins, phenolic compounds, oil and fats, saponins, flavonoids, alkaloids, tannins and phytosterols. Antioxidant activity of the extract was determined by 2, 2-diphenyl-1-picrylhydrazyl radical scavenging activity, metal chelating activity, reducing power activity and DNA damage inhibition activity. Analysis of phenolic compounds was performed by Folin-Ciocalteau reagent method and gradient high performance liquid chromatography technique.@*RESULTS@#Preliminary phytochemical analysis exhibited the presence of phenolic compounds, saponins, flavonoids, tannins and phytosterols as major phytochemical groups. The extract exhibited high 2, 2-diphenyl-1-picrylhydrazyl radical scavenging activity (IC(50)= 110.74 μg/mL), metal chelating activity (IC(50)= 758.17 μg/mL), reducing power activity and DNA damage inhibition efficiency. The extract was reported to possess a high amount of total phenolic content and some of them were identified as gallic acid (3,4,5-OH), apigenin-7-O-glucoside (apigetrin), quercetin-3-O-rutinoside (rutin) and myricetin (3,5,7,3,4,5-OH) by high performance liquid chromatography analysis. The extract was found non toxic towards human erythrocytes in the hemolytic assay (IC(50) = 24.89 mg/mL).@*CONCLUSIONS@#These results conclud that A. lanata stem possesses high antioxidant activity and can be used for the development of natural and safe antioxidant compounds.