Studies on biochemical and synergistic effects of immunosuppressive concentration of imidacloprid with Beauveria bassiana and Metarhizium anisopliae for enhancement of virulence against vector mosquito Culex quinquefasciatus.

In order to increase the virulence of two commonly used entomopathogens namely Beauveria bassiana and Metarhizium anisopliae for effective mosquito control programs, we developed new combined formulation by the use of immunosuppressive concentration of imidacloprid. Exposure of sublethal concentration (LC10 1.34 ppb) of imidacloprid to second instar larvae for 92 h that differently modulated the larval biochemical markers by decreasing the total protein (20.65% reduction), acetylcholinesterase (35.74% reduction) and increases the ß-carboxylesterase (26.59% increase) and acid phosphatase (30.69% increase) levels while no significant difference was noticed in alkaline phosphatase of C. quinquefasciatus. Further we demonstrated that the imidacloprid exposure brings about reduction in phenoloxidase level (39.48% decrease) and nitric oxide production (37.64% decrease) in larval homogenate over control. The reduction in viability of hemocytes (15.37% decrease) and phagocytic activity of hemocytes (32.18% decrease) was noticed in imidacloprid treatment. Moreover in laboratory condition, exposure of 1 × 107 spores/ml of B. bassiana (984) and M. anisopliae (6060) alone for 92 h cumulative toxicity assay exhibited larval mortality of 36.47% and 47.64% respectively against C. quinquefasciatus. However in the synergistic experimental studies with LC10 of imidacloprid and 1 × 107 spores/ml of B. bassiana or M. anisopliae to the larvae for 92 h cumulative assay brought 60% and 50.59% more insecticidal activity than the respective entomopathogens alone. The substantial increase of larvicidal activity noticed in the synergistic test conditions against larvae of C. quinquefasciatus revealed that the inclusion of sublethal concentration was proved to be useful for effective larval control.

Cytotoxicity and Anti-Inflammatory Effects of Polyherbal Formulations, Joint Pain Spl and Rumalaya Forte on Lipopolysaccharide Induced Inflammation in IC-21 Macrophages.

AIM: To test the effectiveness of marketed polyherbal formulations on lipopolysaccharide-induced inflammatory conditions in macrophages. BACKGROUND: Usage of herbal compounds among patients suffering from arthritis and cancer is increasing every year. Many anti-inflammatory herbal products available in the market should be screened thoroughly for their possible mechanism of action. OBJECTIVE: Joint Pain Spl (JPS) is a polyherbal dietary food supplement composed of 13 herbal plants, and Rumalaya Forte (RF) is a polyherbal formulation comprising of 6 herbal plants. These were tested for their cytotoxicity, as well as antioxidant and anti-inflammatory activities in LPS treated IC-21 peritoneal macrophages. METHODS: Commercially available JPS and RF powder was used to prepare the extract. The aqueous and methanol extracts were quantified for the presence of phenolic and flavonoid compounds and confirmed with HPLC. In vitro DPPH free scavenging activity was performed. Cytotoxicity was tested by MTT assay. Anti-inflammatory activity was tested using lipopolysaccharide-stimulated IC-21 peritoneal macrophage cells. RESULTS: The phytochemical screening showed the presence of phenolic and flavonoid compounds in JPS and RF. The aqueous and methanol extracts of JPS and RF possesses significant DPPH free radical scavenging activity. MTT assay revealed that 90.64% (aqueous extract) and 92.21% (methanol extract) of exposed macrophages are viable even after 24h exposure of maximal tested concentrations of herbal formulations. Pre-treatment of JPS and RF on LPS induced IC-21 macrophages showed a reduction in nitric oxide production (maximal 79.95%) and a high level of superoxide anion scavenging activity (maximal 82.5%) over control. CONCLUSION: The two tested polyherbal formulations, such as JPS and RF possess anti-inflammatory activity by modulating free radical generation in IC-21 macrophages. Thus the presence of the phenolic and flavonoid compounds may contribute to the antioxidant activity.

Cytoprotective and anti-inflammatory effects of kernel extract from Adenanthera pavonina on lipopolysaccharide-stimulated rat peritoneal macrophages.

OBJECTIVE: To investigate mechanism of anti-inflammatory activity of Adenanthera pavonina (A. pavonina) extracts. METHODS: Rat peritoneal macrophages were treated with different concentrations of lipopolysaccharide and H2O2 in the presence and absence of kernel extract from A. pavonina. Nitric oxide, Superoxide anion generation, cell viability and nuclear fragmentation were investigated. RESULTS: The pre-treatment of kernel extract from A. pavonina suppressed nitric oxide, superoxide anion, cell death, nuclear fragmentation in lipopolysaccharide and H2O2 stimulated or induced macrophages, respectively. CONCLUSIONS: These results suggest that A. pavonina extract suppresses the intra cellular peroxide production.

Cytoprotective and anti-inflammatory effects of kernel extract from Adenanthera pavonina on lipopolysaccharide-stimulated rat peritoneal macrophages

Objective:To investigate mechanism of anti-inflammatory activity ofAdenanthera pavonina (A. pavonina) extracts.Methods:Rat peritoneal macrophages were treated with different concentrations of lipopolysaccharide andH2O2 in the presence and absence of kernel extract from A. pavonina.Nitric oxide, superoxide anion generation, cell viability and nuclear fragmentation were investigated.Results:The pre-treatment of kernel extract fromA. pavonina suppressed nitric oxide, superoxide anion, cell death, nuclear fragmentation in lipopolysaccharide andH2O2 stimulated or induced macrophages, respectively.Conclusions:These results suggest thatA. pavonina extract suppresses the intra cellular peroxide production.

Green synthesis of silver nanoparticles using Delphinium denudatum root extract exhibits antibacterial and mosquito larvicidal activities.

Green synthesis of silver nanoparticles (AgNPs) using aqueous root extract of Delphinium denudatum (Dd) by reduction of Ag(+) ions from silver nitrate solution has been investigated. The synthesized DdAgNPs were characterized by using UV-Vis spectroscopy, X-ray diffraction (XRD), Field emission scanning electron microscope (FESEM) and Fourier transform infrared spectroscopy (FTIR). The prepared DdAgNPs showed maximum absorbance at 416nm and particles were polydispersed in nature, spherical in shape and the size of the particle obtained was⩽85nm. The DdAgNPs exhibited antibacterial activity against Staphylococcus aureus ATCC 6538, Bacillus cereus NCIM 2106, Escherichia coli ATCC 8739 and Pseudomonas aeruginosa ATCC 9027. The DdAgNPs showed potent larvicidal activity against second instar larvae of dengue vector Aedes aegypti with a LC50 value of 9.6ppm.

Immuno-suppressive effects of aqueous extract of soapnut Sapindus emarginatus on the larvae and pupae of vector mosquito, Aedes aegypti.

We recently reported the presence of potent anti-mosquito activity in aqueous kernel extract of the soapnut, Sapindus emarginatus, and demonstrated its impact on marker enzymes in larvae and pupae of the vector mosquito, Aedes aegypti. As a sequel to these findings, the present study elucidates immunotoxicity of this extract with respect to hemocyte-mediated cellular immune responses in fourth instar larvae and pupae as well as cuticular melanization reaction in the larvae of A. aegypti. The exposure of these two developmental stages of the mosquito to the soapnut extract at a lethal threshold concentration neither affected hemocyte viability tested up to 3h in vitro nor did it influence the hemocyte count. By contrast, exposure of the mosquito larvae and pupae to this extract significantly reduced the ability of their hemocytes to bind yeast cells, an important early event in the process of non-self recognition by immune cells. Consequently, the phagocytic activity of these hemocytes against yeast cells was also found to be adversely affected upon exposure of larvae and pupae to the extract. Besides, a perceptible initial delay in melanization reaction at the injured site of the cuticle in the extract-exposed larvae was observed. All these findings demonstrate, for the first time, the immuno-suppressive potential of a botanical biocide in the vector mosquito.

Effects of extract of soapnut Sapindus emarginatus on esterases and phosphatases of the vector mosquito, Aedes aegypti (Diptera: Culicidae).

Our earlier investigations with kernels from the soapnut Sapindus emarginatus revealed it as a new source of botanical biocide with potent antimosquito activity, as evident from the proven unique ability of the aqueous kernel extract to kill all the developmental stages of three important vector mosquito species, Aedes aegypti, Anopheles stephensi and Culex quinquefasciatus. This extract was also found to be safe for two non-target aquatic insects. As a sequel to these findings, we have further examined quantitative and qualitative changes in total proteins, esterases, and phosphatases in whole body homogenates of fourth instar larvae and pupae of A. aegypti exposed to this extract at an appropriate threshold time for its lethal effect to gain insights into the impact of the botanical biocide on biochemical characteristics of the target vector mosquito at two distinct developmental stages. The profiles of proteins, esterases (acetylcholinesterse, α- and ß-carboxylesterases), and phosphatases (acid and alkaline) exhibited distinct patterns of variation during normal development of fourth instar larvae and pupae, indicating intrinsic difference in biochemical features between these two developmental stages of A. aegypti. Upon exposure of the larvae to the extract, significant reduction in the activities of acetylcholinesterse, ß-carboxylesterase, and acid phosphatases were recorded, whereas the total proteins, α-carboxylesterase and alkaline phosphatase activities were unaffected. By contrast, only alkaline phosphatase activity was significantly affected in pupae exposed to the extract. Analysis of these enzymes in native PAGE revealed that they exist in isoforms in both the larvae and pupae. The alterations in the levels of enzymatic activities observed from the quantitative assays of various enzymes were reflected by the respective zymograms with perceptible differences in the intensity and the number of bands detected especially with ß-carboxylesterase, acid and alkaline phosphatase activity between the control and exposed test organisms. Despite the fact that the soapnut kernel extract causes mortality of both the larvae and pupae of A. aegypti, the findings of this study demonstrate that the impact of this extract is most pronounced in various enzyme profiles of the larvae rather than the pupae. Such discrepancy implicates the presence of unique biochemical mechanisms in the pupae of mosquito for detoxification of botanical biocides.

Antimosquito activity of aqueous kernel extract of soapnut Sapindus emarginatus: impact on various developmental stages of three vector mosquito species and nontarget aquatic insects.

Aqueous (physiological saline) extracts of seed kernel from seven indigenous plants were initially screened for their antimosquito activity against eggs, larvae of all instars, and pupae of Aedes aegypti. Among various seed kernels tested, the soapnut Sapindus emarginatus (Sapindaceae) extract was found to exhibit, for the first time, a strong antimosquito activity as evident from its ability to inflict 100% mortality of all the developmental stages of A. aegypti. Furthermore, the kernel extract of S. emarginatus also exerted ovicidal, larvicidal, and pupicidal activity against two other important vector mosquitoes, namely, Anopheles stephensi and Culex quinquefasciatus. Differential susceptibility of the various developmental stages of the three mosquito species exposed to soapnut extract was also noticed. The kernel extract was found to be safe for two nontarget aquatic insects tested: the larvae of Chironomus costatus and the nymphs of Diplonychus rusticus. Lethal concentration values of soapnut extract to these nontarget insects were always threefold or fivefold higher than those that produced 100% mortality of the larvae of the three mosquito species examined. The findings of this study clearly demonstrate that the aqueous kernel extract of S. emarginatus has potent antimosquito activity detectable against all the developmental stages of three important vector mosquito species as well as it is safe for nontarget aquatic organisms, and thus this new botanical resource could be used as an eco-friendly alternative biocidal agent in control of mosquitoes.