Toxicity of isolated phenolic compounds from Acorus calamus L. to control Spodoptera litura (Lepidoptera: Noctuidae) under laboratory conditions

Background Spodoptera litura (Lepidoptera: Noctuidae), the tobacco cutworm, is an prominent agricultural pest. To reduce the use of chemical pesticides that cause health problems and that leave residue in the environment, some botanical pesticides have been developed. Our research aimed to evaluate the insecticidal efficacy of Acorus calamus L. extract for the control of S. litura under laboratory conditions. Results After 24 h of topical application, the A. calamus methanolic crude extract showed toxicity against secondary instar S. litura larvae (LD50 ~ 7.438 µg/larva). Chrysin (5,7-dihydroxy flavone), one of the isolated phenolic compounds, showed optimal control efficiency (LD50 ~ 2.752 µg/larva) and showed a reduction in carboxylesterase activities, which have detoxification reduction roles in larvae. Conclusion Chrysin in the crude extract of A. calamus may be an active compound to control this pest, and it may be applied as an alternative to minimize the usage of chemical insecticides. Graphical Abstract

Antioxidant ability of Chenopodium formosanum extracted using an ethanol–ammonium sulfate two-phase system

Background Chenopodium formosanum (CF) provides the human body with numerous nutritional components. This study used the two-phase system to identify an efficient method to obtain CF extracts. CF extraction was performed using an ethanol–ammonium sulfate two-phase system. The efficacy of different CF extracts with five types of antioxidant ability was tested and compared with traditional aqueous and alcohol extractions. Results The results showed that a separated top of the two-phase system extract had higher total phenol content (120.35 ± 5.80 mg gallic acid equivalent/g dry extract), total flavonoid content (447.06 ± 16.57 mg quercetin equivalent/g dry extract) and reducing ability (284.48 ± 4.60 mg vitamin C equivalent/g dry extract) than those of other extracts. Furthermore, the separated top of the two-phase system extract and the top of the two-phase system extract had higher 1,1-diphenyl-2-picrylhydrazyl free radical scavenging ability and 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) free radical scavenging ability than those of the water extract, alcohol extract, bottom of two-phase system extract, and separated bottom of two-phase system extract. Conclusions The results indicate that CF has great potential for use in natural plant health supplements and skin care products and that the two-phase extraction system can yield an effective CF extract. Graphical Abstract

Analyses of the oil content, fatty acid composition, and antioxidant activity in seeds of Thlaspi arvense L. from different provenances and correlations with environmental factors

Background Pennycress (Thlaspi arvense L.) is an annual herbaceous plant of the Cruciferae family that has attracted attention as an oil crop and interseeded cover crop. We collected seeds of pennycress from five provenances in Northeast China, compared their characteristics, i.e. oil content, fatty acid composition, physical, chemical and antioxidant properties, their correlations with environmental factors were also analysed. Results There were significant differences in the seed characteristics, oil content, quality indicators and composition among different provenances (P < 0.05). The 1000-seed weight ranged from 0.80 to 1.03 g; seed oil content from 28.89 to 42.57%; iodine from 79.19 to 99.09; saponification value from 186.51 to 199.60; peroxide value from 0.07 to 10.60; and acid value from 0.97 to 13.02. The range of seed oil colours were 66.53–78.78 (L*), 4.51–10.29 (a*), and 105.68–121.35 (b*). Erucic acid (C22:1) was the fatty acids with the highest content in pennycress seed oils (31.12–35.31%), followed by linoleic acid (C18:2 16.92–18.95%) and α-linolenic acid (C18:3 14.05–15.34%). The fatty acid 8,11,14-eicosatrienoic acid (C20:3) was detected for the first time in seed oils from Beian city, Panshi city and Kedong county, with contents of 1.13%, 0.84% and 1.03%, respectively. We compare and report for the first time on the radical-scavenging activity of the seed oils of pennycress. The EC50 values of the DPPH radical-scavenging activity and ABTS+ radical-scavenging activity of the seed oils from different provenances were 8.65–19.21 mg/mL and 6.82–10.61 mg/mL, respectively. The ferric ion reduction antioxidant capacity (FRAP) ranged from 0.11 to 0.30 mmol Fe2+/g, which is equivalent to 4 mg/mL FeSO4 of pennycress seed oils. Conclusions There was a significant correlation between seed characteristics and changes in geographical factors. With increasing longitude, the thickness of seeds, 1000-seed weight, and seed oil content increased, while the acid and peroxide values of the seed oil decreased. As the latitude increased, the 1000-seed weight and seed oil content increased, while the seed oil peroxide value decreased. Furthermore, mean annual temperature and annual rainfall are the two key environmental factors affecting the quality of pennycress. Graphical Abstract

Evaluation of metal nano-particles as growth promoters and fungi inhibitors for cereal crops

Background Nano-particles of metals can be routinely synthesized. The cereal seeds treatment with the particles can improve early growth and crop production. Moreover, the treatment is robust and economical. Methods Metal (Fe0, Cu0, Co0), zinc oxide (ZnO) and chitosan-stabilized silver nano-particles were synthesized and applied to cereal seeds. The germination rate, early plant development and inhibition effects on pathogenic fungi were quantified. Results It was found that all nano-particles had a positive effect on the development of healthy cereal seedlings. In particular, the length of the above-ground part of the seedlings was increased by 8–22%. The highest inhibition effect was observed on Helminthosporium teres with the application of Co0 and chitosan-Ag. Pre-sowing treatment with metal nano-particles reduced the number of infected grains by two times for wheat and 3.6 times for barley. The application also increases the chlorophylls and carotenoids in both uninfected and infected seedlings. Conclusions The results demonstrated a robust application of nano-particles in improving cereal production. Graphical Abstract

Conventional agrochemicals towards nano-biopesticides: an overview on recent advances

Pesticides are classified into several groups based on their structure, including fungicides, insecticides, herbicides, bactericides, and rodenticides. Pesticides are toxic to both humans and pests. For pest control, a very small amount of pesticides reach their target pests. Therefore, nearly all pesticides move through the environment and exert adverse effects on beneficial biota and public health. These chemicals pollute the water, soil, and atmosphere of the ecosystem. Agricultural workers in greenhouses and open fields, exterminators of house pests, and workers in the pesticide industry are occupationally exposed to pesticides. Pesticide exposure in the general population primarily happens through the consumption of food and water contaminated with pesticide residues; however, substantial exposure can also occur outside or inside the house. Currently, intelligent, responsive, biodegradable, and biocompatible materials have attracted considerable interest for the formulation of green, safe, and efficient pesticides. It was indicated that utilizing nanotechnology to design and prepare targeted pesticides with an environmentally responsive controlled release via chemical modifications and compounds offers great potential for creating new formulations. Furthermore, biopesticides include microbial pesticides, which are naturally happening biochemical pesticides. In addition, pesticidal substances generated by plants with added genetic materials, i.e., plant-incorporated protectants (PIPs), have emerged. Based on the foregoing evidence, various types of pesticides are summarized in this review for the first time. Here, new pesticides including nano-pesticides and biopesticides are discussed while focusing on the most recent findings on targeted and safe nano-formulated biopesticides and nano-pesticides. Graphical Abstract

Investigation of important biochemical compounds from selected freshwater macroalgae and their role in agriculture

Background Freshwater macroalgae possess a number of important secondary metabolites. They are an unexplored source of medicinal compounds. In this study, three freshwater macroalgae—Chara vulgaris, Cladophora glomerata and Spirogyra crassa—were collected from the river Swat and the river Kabul in the Charsadda district of Khyber Pakhtunkhwa, Pakistan. To assess the role of freshwater macroalgae in agriculture, various experiments were performed on their extracts. Methanolic extract of the three macroalgae were first analyzed through gas chromatography–mass spectrometry (GC–MS) for the presence of important medicinal secondary metabolites. The methanol based macroalgae extracts were tested for antibacterial, insecticidal, cytotoxic and phytotoxic activities. Results Initially, the algae were dried, crushed and treated with methanol for the extraction of secondary metabolites. The GC–MS results contained several important long chain fatty acids and other related long-chain hydrocarbons, such as alkanes and alkenes. Several benzene derivatives were also detected during the course of the investigation. Several of these compounds have established roles in the treatment of human ailments and can be supplied to farm animals. For example, phenylephrine is a decongestant, dilates pupils, increases blood pressure and helps in relieving hemorrhoids. Hexahydropseudoionone has uses in perfumes and other cosmetics. Several essential oils were also detected in the methanolic extract of the three macroalgae that can be utilized in various industrial products. Bioassays showed that these algal extracts—especially the Spirogyra sp. extract—contain moderate to maximum bioactivity. Conclusions Macroalgae possess important secondary metabolites with medicinal properties. These secondary metabolites can be used as biopesticides, plant growth enhancers, and remedies for various diseases in farm animals and for the control of weeds. They can be further explored for isolation and purification of useful biochemical compounds. Graphical Abstract

Genotype influence on shelf life behaviour of minimal processed loquat (Eriobotrya japonica (Thunb.) Lindl.) fruit: the role of sugar, acid organics and phenolic compounds

Background Loquat cultivars cultivated in Southern Italy are very appreciated by consumers for their sensorial characteristics, such as persistent aroma and taste. Apposite maturity indexes for peeling and processing loquat fruit were investigated to increase diffusion of minimally processed loquat. The genotype’s effect on the minimally processed loquat fruit shelf life and quality harvested at commercial maturity (80% yellow color) was investigated on peeled fruit stored at 5 °C for 10 days. The role of sugars, organic acids and phenols composition was observed through in depth qualitative analysis. In addition, several qualitative analyses were carried out to determine the quality of minimal processed fruit. Results Loquat fruits harvested at commercial ripening stage performed very good palatability and flesh color persistency. Late ripening fruits genotypes shown a low rate of pulp oxidation and quality decay, while early ripening fruits were not suitable for fresh-cut. Genotype had a great influence on weight loss, β-carotene content, fruit respiration, ascorbic acid and total phenols content during the shelf life. Conclusions This work shows how the amount of the composition of sugars and organic acids as an intrinsic characteristic of genotype influences the quality of loquat fruits minimal processed. The higher values of glucose, sorbitol and ascorbic acid accumulated in the cv ‘Nespolone Trabia’ contributed to a reduction in chilling injury and oxidative stress after cutting. Graphical Abstract

The treatment of the organic fraction of municipal solid waste (OFMSW) as a possible source of micro- and nano-plastics and bioplastics in agroecosystems: a review

Plastics fragmentation into smaller debris, namely, micro- and nano-plastics (MPs and NPs), is a matter of global concern because of their wide distribution in terrestrial and marine environments. The latest research has focused mainly on aquatic ecosystems, and fragmentation of bioplastics into micro- and nano-particles (MBPs and NBPs) is not considered. The distribution, concentration, fate and major source of MPs, NPS, MBPs and NBPs in agroecosystems still need to be understood. The use of composts and sewage sludge from the organic fraction of municipal solid waste (OFMSW) treatment plants as soil amendments is likely to represent a major input of these debris. The present review provides insights into the current evidence of pollution from micro- and nano-particles of both fossil- and bio-origin in the OFMSW treatment, and aims at evaluating if the recycling of organic waste and its application as a soil fertilizer outweigh the risk of pollution in terrestrial environments. Huge unpredictability exists due to the limited numbers of data on their quantification in each source of possible solution. Indeed, the major hurdles arise from the difficult to quantify the micro-, especially the nano-, particles and subsequently assess the concentrations in the environments, as well as bioaccumulation risks, and toxic effects on organisms. Graphical Abstract

Removal of iron and manganese from groundwater sources using nano-biosorbents

Background The presence of iron (Fe) and manganese (Mn) ions in rocky beds leads to groundwater pollution. Moreover, their excessive concentration causes bad taste and color stains of water. Methods Tea leaves-derived char (TLC), rice straw-derived char (RSC), and nanosilica (NS) were used to adsorb Fe and Mn ions from water sources. The effects of parameters such as contact time, composition percentage, and particle size of biosorbents in a fixed-bed adsorption column were investigated. Results The study on the adsorption of Fe and Mn ions showed that the amount of adsorption increased significantly by decreasing the particle size. Furthermore, the combination of nano-biosorbents with nanosilica improved the adsorption. The Thomas and Adams–Bohart models adequately indicated the adsorption of Fe and Mn ions onto nano-biosorbents in the column mode. The TLC and RSC with NS are applicable for the removal of Fe and Mn ions from groundwater. Conclusions According to the BET analysis results, with more crushing of biosorbents by ball mill and placing them in the furnace, specific surface area of tea leaves and rice straw increased from 0.29 to 3.45 and from 3.70 to 10.99 m2/g, respectively. The absorption of iron and manganese from the aqueous solution increased with the percentage of nano-silica. According to breakthrough curves, under best conditions (the seventh mode), nano-biosorbents could remove 98.05% and 97.92% of iron and manganese ions, respectively. The maximum equilibrium capacity of the adsorption column (mg/g) was 256.56 for iron and 244.79 for manganese. Graphical abstract

Encapsulation of thyme essential oil using electrospun zein fiber for strawberry preservation

Background Strawberry is a nutrient-rich and important small fruit because of its high content of beneficial phytochemicals and several vitamins like vitamin C, vitamin E and vitamin B6. However, strawberry is highly perishable due to its susceptibility to mechanical damage, microbiological decay, and softening in texture. Recently, there has been an increasing interest in using various essential oils as natural food preservatives. Although, they have limited stability to exposure to high temperatures, light and oxygen, which could eventually affect sensory quality attributes. The electrospinning method is a simple and well-organized process that has been used to encapsulate essential oils. In this study, the effect of thyme essential oil (TEO) encapsulated into zein electrospun fiber film was assessed on extending the shelf life and preserving the quality of strawberry fruit during storage. Findings Results indicated that TEO presented potent antibacterial activity against Bacillus cereus, Escherichia coli and Aspergillus fumigatus. The scanning electron microscopy images of zein fiber had a linear shape, absence of beads, and smooth surface. The encapsulation efficiency (EE) of TEO in the zein fiber was about 75.23%. Encapsulated TEO released at a slower rate than free TEO. The zein/TEO fibers (zein fiber film loaded with TEO) significantly (p ˂ 0.05) decreased weight loss and maintained the anthocyanin content, firmness and color of the strawberries during storage. After 15 days of storage, weight loss reduced about 15% and firmness was higher about 20% in packed fruit with zein/TEO fibers compared to control. Conclusions Interestingly, after 15 days of cold storage, the strawberries firmness, appearance, and sensory evaluation, which are important quality factors from both postharvest and consumers’ viewpoint, in zein/TEO fiber treatment were acceptable and had higher scores compared to the control. In conclusion, the present study demonstrated the benefits of incorporating TEO into zein films, which could play a significant role in the active packaging and preservation of strawberry fruits. Graphical Abstract