Insecticidal efficacy and possibility of Combretum trifoliatum Vent. (Myrtales: Combretaceae) extracts in controlling Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae).

BACKGROUND: The fall armyworm Spodoptera frugiperda (J.E. Smith), is an important pest of agronomical crops. It is interesting to discover secondary metabolites in plants that are environmentally safer than synthetic pesticides. For this purpose, Combretum trifoliatum crude extract and its isolated compounds were investigated for their insecticidal activities against S. frugiperda. RESULTS: The median lethal dose (LD50 ) was evaluated in the second-instar larvae using the topical application method. The isolated compounds, apigenin and camphor, demonstrated a highly toxic effect on larvae at a lower LD50 dose than crude extract. Moreover, when the larvae were exposed to crude extract concentrations, the development to pupa and adult stages was reduced by more than 50%. The ovicidal toxicity was examined using a hand sprayer. The extract concentration 5, 10, and 20 µg/egg significantly decreased the egg hatchability. In addition, crude extract showed a significant difference in inhibiting acetylcholinesterase (AChE) activity while crude extract and camphor showed significant inhibitory effects on carboxylesterase (CE) and glutathione-S-transferase (GST) activities. CONCLUSION: The crude ethanol extract of Combretum trifoliatum was toxic to S. frugiperda in terms of larval mortality, negatively affecting biological parameters, and decreasing egg hatchability. Additionally, the activities of cholinergic and detoxifying enzymes were affected by crude extract and its isolated compounds. These results highlight that Combretum trifoliatum might be efficient as a bioinsecticide to control S. frugiperda. © 2023 Society of Chemical Industry.

Antiproliferation and antibacterial effect of biosynthesized AgNps from leaves extract of Guiera senegalensis and its catalytic reduction on some persistent organic pollutants.

The study concentrate on the biosynthesis of silver nanoparticles (AgNps) from the leaves extract of Guiera senegalensis with focus on its; antiproliferation effect on prostate (PC3), breast (MCF7) and liver (HepG2) cancer cell lines, antibacterial effect on Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) and the degradation on 4-nitrophenol (4-NP) and congo red dye (CR). The synthesized AgNps were characterized by FTIR, TEM, FESEM, XRD and EDX analysis. The EDS spectrum revealed that the synthesized nanoparticles (Nps) were composed of 55.45% Ag atoms of spherical shape with approximately 50nm size, identified from TEM and FESEM data. The antiproliferation effect of the AgNps varies with cell lines in a concentration dependent manner. The result showed that the AgNps were more effective on PC3 (IC50 23.48µg/mL) than MCF7 (29.25µg/mL) and HepG2 (33.25µg/mL) by the virtue of their IC50 values. The AgNps were highly effective against E. coli and S. aureus by killing 99% colonies. The AgNps also shows a good catalytic reduction of the toxic organic pollutants in which only 3mg of the AgNps degraded 95% of both CR dye and 4-NP in 22 and 36min respectively. Therefore, the green synthesis of AgNps may have potential applications in pharmacology and industries for the treatment of cancers, bacterial infections and in degrading toxic organic pollutants in water.

One-pot biogenic fabrication of silver nanocrystals using Quisqualis indica: Effectiveness on malaria and Zika virus mosquito vectors, and impact on non-target aquatic organisms.

Currently, mosquito vector control is facing a number of key challenges, including the rapid development of resistance to synthetic pesticides and the recent spread of aggressive arbovirus outbreaks. The biosynthesis of silver nanoparticles (AgNPs) is currently considered an environmental friendly alternative to the employ of pyrethroids, carbamates and microbial agents (e.g. Bacillus thuringiensis var. israelensis), since AgNPs are easy to produce, effective and stable in the aquatic environment. However, their biophysical features showed wide variations according to the botanical agent using for the green synthesis, outlining the importance of screening local floral resources used as reducing and stabilizing agents. In this study, we focused on the biophysical properties and the mosquitocidal action of Quisqualis indica-fabricated AgNPs. AgNPs were characterized using spectroscopic (UV, FTIR, XRD) and microscopic (AFM, SEM, TEM and EDX) techniques. AFM, SEM and TEM confirmed the synthesis of poly-dispersed AgNPs with spherical shape and size ranging from 1 to 30nm. XRD shed light on the crystalline structure of these AgNPs. The acute toxicity of Quisqualis indica extract and AgNPs was evaluated against malaria, arbovirus, and filariasis vectors, Anopheles stephensi, Aedes aegypti and Culex quinquefasciatus, as well as on three important non-target aquatic organisms. The Q. indica leaf extract showed moderate larvicidal effectiveness on Cx. quinquefasciatus (LC50=220.42), Ae. aegypti (LC50=203.63) and An. stephensi (LC50=185.98). Q. indica-fabricated AgNPs showed high toxicity against Cx. quinquefasciatus (LC50=14.63), Ae. aegypti (LC50=13.55) and An. stephensi (LC50=12.52), respectively. Notably, Q. indica-synthesized AgNPs were moderately toxic to non-target aquatic mosquito predators Anisops bouvieri (LC50=653.05µg/mL), Diplonychus indicus (LC50=860.94µg/mL) and Gambusia affinis (LC50=2183.16µg/mL), if compared to the targeted mosquitoes. Overall, the proposed one-pot biogenic fabrication of AgNPs using Q. indica is a low-cost and eco-friendly tool in the fight against Zika virus, malaria and filariasis vectors, with little impact against non-target aquatic mosquito predators.

Secondary metabolites and nutrients of woody plants in relation to browsing intensity in African savannas.

Carbon-based secondary metabolites (CBSMs) are assumed to function as defences that contribute to herbivore-avoidance strategies of woody plants. Severe browsing has been reported to reduce concentrations of CBSMs and increase N concentrations in individual plants, causing heavily browsed plants to be characterised by N-rich/C-poor tissues. We hypothesised that concentrations of condensed tannins (CT) and total polyphenols (TP) should decrease, or N increase, in relation to increasing intensity of browsing, rendering severely browsed plants potentially more palatable (increased N:CT) and less N-limited (increased N:P) than lightly browsed ones. We sampled naturally browsed trees (taller than 2 m) of four abundant species in southern Kruger National Park, South Africa. Species-specific relationships between N:CT, CT, TP and P concentrations and increasing browsing intensity were detected, but N and N:P were consistently invariable. We developed a conceptual post-hoc model to explain diverse species-specific CBSM responses on the basis of relative allocation of C to total C-based defence traits (e.g. spines/thorns, tough/evergreen leaves, phenolic compounds). The model suggests that species with low allocation of C to C-based defence traits become C-limited (potentially more palatable) at higher browsing intensity than species with high allocation of C to C-based defences. The model also suggests that when N availability is high, plants become C-limited at higher browsing intensity than when N availability is low.

Effect of different dietary levels of mangrove (Laguncularia racemosa) leaves and spice supplementation on productive performance, egg quality, lipid metabolism and metabolic profiles in laying hens.

In order to study the influence of white mangrove (Laguncularia racemosa) leaves on productive performance, egg quality, lipids metabolism and metabolic profiles, 180 Hy-line laying hens were randomly distributed to 6 dietary treatments each contained 6 replicates of 5 individually caged hens during the period from 50 to 60 weeks of age. 2. Three isoenergetic and isonitrogenous diets were formulated to contain 0, 50 and 100 g/kg of sun-dried mangrove leaves. Each diet was fed with or without supplementation of 2 g of cardamom, cumin, hot and black pepper mixture (1:1:1:1)/kg diet. 3. Mangrove leaves at either 50 or 100 g/kg adversely affect laying rate, egg mass and FCR, whilst increasing water intake and water to feed ratio. Mangrove leaves had no significant effect on dry matter, protein, lipid, cholesterol and ash content of liver, or on dry matter, protein and ash of yolk. 4. Plasma total protein, total lipids; liver enzymes AST and ALT and mortality rate were not significantly affected by mangrove leaves. On the other hand, yolk lipid, yolk cholesterol and plasma cholesterol significantly decreased, while yolk colour significantly increased with inclusion of 50 or 100 g/kg mangrove leaves, and Haugh unit score significantly increased with 100 g/kg mangrove leaves. 5. Spice mixture significantly increased egg weight by 2.2%. Yolk lipid content significantly decreased by 2.6%, while yolk colour and Haugh unit significantly increased with inclusion of spice mixtures. 6. In conclusion, mangrove leaves at 50 g/kg may be included in the laying hen diets as a means of decreasing lipid and cholesterol in yolk and plasma cholesterol and increasing yolk colour. Spice mixture at 2 g of cardamom, cumin, hot and black pepper mixture (1:1:1:1)/kg diet increased laying rate, egg mass, Haugh unit score and yolk colour while decreasing yolk lipids.

Hepatoprotective evaluation of Anogeissus latifolia: in vitro and in vivo studies.

AIM: To evaluate the hepatoprotective activity of a hydroalcoholic extract of the bark of Anogeissus latifolia; in vitro in primary rat hepatocyte monolayer culture and in vivo in the liver of Wistar rats intoxicated by carbon tetrachloride (CCl(4)). METHODS: In the in vitro study, a primary hepatocyte monolayer culture was treated with CCl(4) and extract of Anogeissus latifolia. Hepatoprotective activity was demonstrated in the CCl(4) damaged primary monolayer culture. In the in vivo study, the hepatoprotective activity of a hydroalcoholic extract of Anogeissus latifolia was analyzed in liver injured CCl(4)-treated rats. Biochemical parameters including serum transaminases [aspartate aminotransferase (AST) and alanine aminotransferase (ALT)] and alkaline phosphatase (ALP) in serum were analyzed. The biochemical findings were supplemented with histopathological examination of rat liver sections. RESULTS: In vitro: primary hepatocyte monolayer cultures were treated with CCl(4) and extract of Anogeissus latifolia. A protective activity could be demonstrated in the CCl(4) damaged primary monolayer culture. In vivo: Hydroalcoholic extract of Anogeissus latifolia (300 mg/kg) was found to have protective activity in rats with CCl(4)-induced liver damage as judged from serum marker enzyme activity. CONCLUSION: The above findings lead to the conclusion that the hydroalcoholic extract of Anogeissus latifolia is hepatoprotective. Hence, we suggest that the inclusion of this plant in the management of liver disorders is justified.