Paramasivam Deepak

Structural characterization and evaluation of mosquito-larvicidal property of silver nanoparticles synthesized from the seaweed, Turbinaria ornata (Turner) J. Agardh 1848

Abstract The silver nanoparticles synthesized from Turbinaria ornata (To-AgNPs) showed spherical with crystalline nature (20–32 nm) was evaluated against fourth instar larvae of three mosquitoes. The maximum activity of To-AgNPs was recorded on Aedes aegypti followed by Anopheles stephensi and Culex quinquefasciatus with the following lethal concentration values (μg/ml): LC50 of 0.738, 1.134, and 1.494; and LC90 of 3.342, 17.982, and 22.475, respectively. The obtained respective values (μg/ml) vis-a-vis aqueous extract (To-AE) were: 2.767 and 40.577; 4.347 and 158.399, and 7.351 and 278.994. The findings revealed that To-AgNPs could form a base for the development of an eco-friendly, low-cost pesticide.

GC–MS analysis of bioactive components and synthesis of gold nanoparticle using Chloroxylon swietenia DC leaf extract and its larvicidal activity

A rapid bio-reduction of chloroauric acid (HAuCl4) was achieved by Chloroxylon swietenia DC leaf extract (CSLE), which resulted in the formation of well dispersed C. swietenia gold nanoparticles (CSGNPs). The formation of GNPs was confirmed by color changes from yellowish green to purple and their characteristic peak at 545 nm. The characterization of synthesized CSGNPs was made through X-ray diffraction (XRD), fourier transform infrared spectroscopy (FTIR), high resolution transmission electron microscopy (HRTEM) equipped with energy dispersive X-ray spectroscopy (EDX) followed by size and zeta potential analyses. The GC-MS profile of C. swietenia methanolic leaf extract (CSMLE) resulted 20 phytocomponents, among those heptacosanoic acid, 25-methyl-, methyl ester (C29H58O2) attributes highest peak area. The efficiency of the synthesized CSMLE, CSGNPs and CSLE were tested against fourth instar larvae of malarial and dengue vector, which resulted more substantial upshot than with leaf extract treated. The Lethal concentration (LC50) values of CSMLE, CSGNPs and CSLE were found to be 0.509, 0.340, 0.423 ppm and 0.602, 0.188, 0.646 ppm on Aedes aegypti and Anopheles stephensi, respectively. The findings form an important baseline information proceeding biologically innocuous biopesticide for controlling the malarial and dengue vectors.

Mosquito-larvicidal efficacy of gold nanoparticles synthesized from the seaweed, Turbinaria ornata (Turner) J.Agardh 1848

ABSTRACT Malaria is considered a dreadful mosquito-borne infectious disease of human beings caused and spread by biting of the female mosquito Anopheles stephensi infected with a parasitic protozoan Plasmodium falciparum. Continuous application of chemicals/synthetic insecticides for vector control causes various problems such as resistant mechanism of mosquito, toxicity to nontarget aquatic organisms and disturbance to the microbial community of the soil. Currently, green synthesized nanoparticles are being employed in various biological processes including insect and pest control. The present investigation focused on the mosquito-larvicidal property of Turbinaria ornata-mediated gold nanoparticles (To-AuNPs) and its boiled aqueous extract (To-AE) against the malarial vector A. stephensi. The recorded lethal concentration (LC50 and LC90) values (µg/ml) of To-AE and To-AuNPs against fourth instar larvae of A. stephensi were 37.77 and 159.55 and 12.79 and 78.70, respectively. The To-AuNPs were characterized through UV-visible spectroscopy, Fourier transform infrared spectroscopy (FTIR), x-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), high-resolution transmission electron microscopy (HRTEM), energy dispersive x-ray spectroscopy (EDX), zeta potential and dynamic light scattering (DLS) method. The presently synthesized gold nanoparticles through the single-step, eco-friendly method is a potentially effective mosquitocidal agent.

Isolation, structural elucidation and antiplasmodial activity of fucosterol compound from brown seaweed, Sargassum linearifolium against malarial parasite Plasmodium falciparum

Abstract The brown seaweed, Sargassum linearifolium (Turner) C. Agardh, 1820 is commonly available along the south-east coast of India. Its compound fucosterol was isolated and confirmed through spectral characterisation and chemical transformation methods. The antiplasmodial effect of the isolated fucosterol was investigated against the 3D7 chloroquine sensitive Plasmodium falciparum strain, parasitaemia percentage was determined at 48 h and morphological change was studied through microscopic examination after Giemsa staining. A perceptible antiplasmodial effect was produced by fucosterol compound against the P. falciparum and positive control, chloroquine with the IC50 values (μg/mL) of 7.48 and 12.81, respectively. Fucosterol showed higher antiplasmodial activity as compared to chloroquine. It is inferred that both the fucosterol and chloroquine could have inhibited the schizont stage of the parasite during the intra-erythrocyte asexual development. The findings underline the usefulness of the seaweed-based fucosterol and further studies are warranted.

Target and non-target toxicity of fern extracts against mosquito vectors and beneficial aquatic organisms

Dengue and malaria are significant mosquito-borne diseases that are rapidly spread worldwide, mainly in temperate countries. Pteridophytes were identified to be a significant source of novel mosquitocidal agents. The present research was to explore the eco-friendly larvicides from methanol extracts of ferns, viz., Actiniopteris radiata, Adiantum caudatum, Cheilanthes swartzii, Hemionitis arifolia and Lycopodium clavatum. The larvicidal potential of the extracts screened using larvae of dengue vector Aedes aegypti (III and IV instar) and malarial vector Anopheles stephensi (III and IV instar), showed 10-100% mortality rates. Biosafety assessment was made on embryos of Danio rerio and Artemia nauplii. The phyto-constituents of the methanol extract of A. radiata leaves were identified through gas chromatography-mass spectrometry (GC-MS). Methanolic leaf extracts of A. radiata, A. caudatum and C. swartzii exhibited larvicidal activity against III and IV instar larvae of Ae. aegypti (LC50: 37.47, 74.51 and 152.38 and 67.58, 95.89 and 271.46 ppm) and An. stephensi (LC50: 70.35, 112.12 and 301.05 and 113.83, 175.30 and 315.19 ppm), respectively. The GC-MS of the methanol extract of A. radiata leaves revealed the presence of 7 phyto-components among which, Carbamic acid, phenyl-, (2-Nitrophenyl) methyl ester (1), Benzoic acid, 3- methylbenzoate (2) and 4-(benzylimino)- 1,4-dihydro-1-(p-toluoylmethyl) pyridine (3) were dominant. Biosafety assessment of methanol extract of A. radiata leaves on embryos of Danio rerio (Zebra fish) and Artemia nauplii (micro crustacean) revealed that there were no destructive or teratogenic effects. To conclude, the larvicidal activity and insignificant toxicity to non-target aquatic organisms of A. radiata leaves makes it a potential and environment safe biocontrol agent against dengue and malarial vectors.

GC-MS Metabolite Profiling, Antibacterial, Antidiabetic and Antioxidant Activities of Brown Seaweeds, Sargassum wightii Greville Ex J. Agardh, 1848 and Stoechospermum marginatum (C. Agardh) Kützing 1843

Objectives: The present study focuses on antibacterial, antidiabetic and antioxidant activities of methanolic extracts of brown seaweed Stoechospermum marginatum (SMME) and Sargassum wightii (SWME). Methods: The antibacterial activities of the seaweed extracts were determined by agar well diffusion method. Phytochemical, antioxidant and antidiabetic activity of the selected seaweed extracts were performed. Results: The phytochemical analysis of SMME and SWME has confirmed the presence of fixed oil, fat, tannin, flavonoids, alkaloids, steroids, phenol compounds, saponin etc. The SWME showed maximum activity against Staphylococcus aureus and minimum activity against Escherichia coli. And the SMME has shown moderate activity against S. aureus. The antidiabetic efficacy of SWME revealed the maximum effect with the inhibitory concentration value (IC50: 58.36 μg/mL) followed by SMME. The SWME has showed the highest scavenging property in all the tested assays (DPPH, FRAP and H2O2) in relation to the control, ascorbic acid. The bioactive metabolites of the extracts were chemically characterized by FTIR and GCMS analyses. GC-MS analysis of SWME revealed the presence of a major chemical compound, hexadecenoic acid, methyl ester (13.35%) which might be responsible for the recorded activity. The FTIR spectrum analyses of crude extracts revealed the presence of alkyl halides, alkanes, amides, aromatics and carboxylic acids. Hence, the present study could form a base-line for the effective biomedical utilization of the seaweed, S. wightii.

Phytochemical profiling of Turbinaria ornata and its antioxidant and anti-proliferative effects

Objectives To analyse the phytochemicals and evaluate the antioxidant and anti-proliferative ability of Turbinaria ornata (Turner) J. Agardh, 1848. Methods A phytochemical analysis of the T. ornata-hexane extract (To-HE) and T. ornata-aqueous extract (To-AE) was performed. T. ornata extracts were analysed by gas chromatography-mass spectrometry (GC-MS), Fourier transform infrared spectroscopy (FTIR) and high-performance liquid chromatography (HPLC). The antioxidant properties of To-HE and To-AE were determined by 2,2-diphenyl-1-picrylhydrazyl radical scavenging (DPPH) and ferric ion reducing power (FRAP) assays. In addition, the in vitro anti-proliferative properties of To-HE and To-AE were assessed in kidney epithelial cells from the African green monkey (Vero) and in adenocarcinomic human alveolar basal epithelial cells (A549) using the MTT (3-(4,5-dimethylthiazol- 2yl)-2,5-diphenyltetrazolium bromide, a yellow tetrazole) assay. Results The phytochemical screening of T. ornata revealed the presence of saponin, alkaloids, amino acids, fixed oil and fat and phenolic compounds (tannins, flavonoids and total phenol). A higher antioxidant ability was found in To-HE than in To-AE. The anti-proliferative efficacy values (μg/mL) of To-HE and To-AE for A549 and Vero cells were 62.91 and 93.00 and 72.64 and 106.6, respectively. The FTIR analysis revealed the presence of functional groups such as alcohols, amides, aromatics, amines, alkyl halides, alkynes, alkanes and carboxylic acids. The GC-MS analysis of To-HE revealed the presence of 13 active compounds. Conclusion Owing to its recorded anti-proliferative effect, further pharmaceutical studies on the development of this anticancer drug are merited.

Antigonon leptopus: a potent biological source for extermination of fish bacterial pathogens Providencia and Aeromonas

This study pertains to the phytochemical components and the biological properties of the weed, Antigonon leptopus Hook. & Arn. (AUT/PUS/064). Phytochemical screening of methanolic leaf extract of A. leptopus revealed the presence of saponin, phenolic compounds, tannins, flavonoids, alkaloids, fixed oils and amino acids. Accordingly, 12 phytochemical components were analysed and characterised by GC–MS. Antibacterial activity was evaluated against fish and clinical pathogens. Fish pathogens, Providencia vermicola (MTCC 5578) and Aeromonas hydrophila (MTCC 646) were more sensitive to the methanolic leaf extract than clinical pathogens. A useful information was obtained from the phytochemistry of A. leptopus leaves, which would pave way to further applications to treat fish diseases and for utility in the pharmaceutical field.