Kinnow peel extract as a reducing and capping agent for the fabrication of silver NPs and their biological applications

Green synthesized AgNPs of the Anchusa arvensis aqueous extract resulting in impressive protein kinase, antioxidant, antibacterial, and antifungal activities

This study focused on analyzing the pharmacological activities of AgNPs synthesized from an aqueous plant extract of Anchusa arvensis. The effectiveness of AgNPs was evaluated for protein kinase inhibition, antioxidant, antibacterial, and antifungal activities. The AgNPs and plant were used to regulate the protein kinase activity using the liquid TSB and ISP4 medium protein kinase inhibition study demonstrated that nanoparticles exhibited a larger zone of inhibition (9.1 ± 0.8) compared to the plant extract (8.1 ± 0.6). The antioxidant activity was assessed using DPPH reagent, and the results indicated that AgNPs displayed potent free radical scavenging properties. In terms of antibacterial activity, AgNPs showed higher efficacy against Enterobacter aerogens (20.1 ± 0.9), Bordetella bronchiseptaca (19.1 ± 0.9), and Salmonella typhimurium (17.2 ± 0.8) at 4 mg/mL. The antifungal activity of AgNPs was prominent against Aspergillus fumagatus (14.1 ± 0.9), Mucor species (19.2 ± 0.8), and Fusarium solani (11.2 ± 0.8) at 20 mg/mL. These findings suggest that AgNPs possess multiple beneficial properties, including bactericidal/fungicidal effects, protein kinase inhibition, and potential free radical scavenging abilities. Therefore, AgNPs have potential applications in various fields, such as biomedicine and industry, due to their ability to counteract the harmful effects of free radicals.

Valorisation of fruit peel bioactive into green synthesized silver nanoparticles to modify cellulose wrapper for shelf-life extension of packaged bread

Fruit peels are rich source of bioactive compounds such as polyphenols, flavonoids, and antioxidants but are often discarded as waste due to limited pharmaceutical and nutraceutical applications. This study aimed to valorise pomegranate and citrus fruit peel into green synthesised silver nanoparticles (AgNPs) in order to modify cellulose-based wrapping material for prospective food packaging applications and propose an alternate and sustainable approach to replace polyethene based food packaging material. Four different concentrations of AgNO₃ (0.5 mM, 1 mM, 2 mM, and 3 mM) were used for green synthesis of AgNPs from fruit peel bioactive, which were characterised followed by phytochemical analysis. Ultraviolet-Visible spectroscopy showed surface plasmon resonance at 420 nm, XRD analysis showed 2θ peak at 27.8°, 32.16°, 38.5°, 44.31°, 46.09°, 54.76°, 57.47°, 64.61° and 77.50° corresponding to (210), (122), (111), (200), (231), (142), (241), (220) and (311) plane of face centred cubic crystal structure of AgNPs. Fourier-transform infrared spectroscopy analysis of AgNPs green synthesised from pomegranate and kinnow peel extract showed a major peak at 3277, 1640 and 1250-1020 1/cm while a small peak at 2786 1/cm was observed in case of pomegranate peel extract which was negligible in AgNPs synthesized from kinnow peel extract. Particle sizes of AgNPs showed no statistically significant variance with p > 0.10 and thus, 2 mM was chosen for further experimentation and modification of cellulose based packaging material as it showed smallest average particle size. Zeta potential was observed to be nearly neutral with a partial negative strength due to presence of various phenolic compounds such as presence of gallic acid which was confirmed by ultrahigh performance liquid chromatography-photodiode array(UHPLC-PDA) detector. Thermal stability analysis of green synthesised AgNPs qualified the sterilisation conditions up to 100 °C. AgNPs green synthesized from both the peel extracts had higher polyphenolic content, antioxidant and radical scavenging activity as compared to peel extracts without treatment (p < 0.05). The cellulose based food grade packaging material was enrobed by green synthesised AgNPs. The characterisation of modified cellulose wrappers showed no significant difference in thickness of modified cellulose wrappers as compared with untreated cellulose wrapper (p > 0.42) while weight and grammage increased significantly in modified cellulose wrapper (p < 0.05). The colour values on CIE scale (L*, a* and b*) showed statistically significant increase in yellow and green colour (p < 0.05) for modified cellulose wrappers as compared to control wrapper. The oxygen permeability coefficient, water vapour permeability coefficient, water absorption capacity and water behaviour characteristics (water content, swelling degree and solubility) showed significant decrease (p < 0.05) for modified cellulose wrapper as compared to control wrapper. A uniform distribution and density of green synthesised AgNPs across cellulose wrapper matrix was observed through scanning electron microscopy (SEM) images with no significant aggregation, confirming successful enrobing and stable immobilisation of nanoparticles from cellulose matrix. A seven-day storage study of bread wrapped in modified and control cellulose wrappers showed delayed occurrence of microbial, yeast and mould count in bread packaged in modified cellulose wrappers and thus, resulting in shelf life extension of bread. The results are encouraging for the potential applications of modified cellulose wrappers to replace polyethene based food packaging.

Metallic and non-metallic nanoparticles from plant, animal, and fisheries wastes: potential and valorization for application in agriculture

Global agriculture is facing tremendous challenges due to climate change. The most predominant amongst these challenges are abiotic and biotic stresses caused by increased incidences of temperature extremes, drought, unseasonal flooding, and pathogens. These threats, mostly due to anthropogenic activities, resulted in severe challenges to crop and livestock production leading to substantial economic losses. It is essential to develop environmentally viable and cost-effective green processes to alleviate these stresses in the crops, livestock, and fisheries. The application of nanomaterials in farming practice to minimize nutrient losses, pest management, and enhance stress resistance capacity is of supreme importance. This paper explores innovative methods for synthesizing metallic and non-metallic nanoparticles using plants, animals, and fisheries wastes and their valorization to mitigate abiotic and biotic stresses and input use efficiency in climate-smart and stress-resilient agriculture including crop plants, livestock, and fisheries.

Fruit peel bioactives, valorisation into nanoparticles and potential applications: A review

Nanotechnology is a rapidly growing field with profound applications in different domains, particularly in food science and technology. Nanoparticles (NPs) synthesis, an integral part of nanotechnology-based applications, is broadly classified into chemical, physical and biosynthesis methods. Chemically sensitive and energy-intensive procedures employed for NPs synthesis are some of the limits of traditional chemical approaches. Recent research has focused on developing easy, nontoxic, cost-effective, and environment-friendly NPs synthesis during the last decade. Biosynthesis approaches have been developed to achieve this goal as it is a viable alternative to existing chemical techniques for the synthesis of metallic nanomaterials. Fruit peels contain abundant bioactive compounds including phenols, flavonoids, tannins, triterpenoids, steroids, glycosides, carotenoids, anthocyanins, ellagitannins, vitamin C, and essential oils with substantial health benefits, anti-bacterial and antioxidant properties, generally discarded as byproduct or waste by the fruit processing industry. NPs synthesized using bioactive compounds from fruit peel has futuristic applications for an unrealized market potential for nutraceutical and pharmaceutical delivery. Numerous studies have been conducted for the biosynthesis of metallic NPs such as silver (AgNPs), gold (AuNPs), zinc oxide, iron, copper, palladium and titanium using fruit peel extract, and their synthesis mechanism have been reported in the present review. Additionally, NPs synthesis methods and applications of fruit peel NPs have been discussed.

The fabrication of paper separation channel based SERS substrate and its recyclable separation and detection of pesticides

In this article, a modified paper separation channel SERS substrate was fabricated by a pen writing method for the simultaneous separation and detection of thiuram and dimethoate. The hydrophilic channel was fabricated with both sides of hydrophobic barrier by the Alkylketene dimer (AKD) modified paper substrate, of which the flow dynamic was well conformed to the Lucas-Washburn model and could be used to separate pesticides effectively. As modified by Ag nanoparticles (AgNPs) and ZnO nanoparticles (ZnONPs), the hydrophilic channel exhibited high recyclable SERS detection activity and stability. The separation and detection performance with different target proportion, channel width and sample volume were studied in detail, which have significant influence on the diffusion process. Additionally, the Raman detects intensity on the substrate also showed linear relationship from 100 to 1000 μg/L. The calculated limit of detects (LODs) under optimal experimental conditions were 54.57 and 19.16 μg/L for dimethoate and thiuram, respectively. Due to the loading of ZnONPs, the substrate could be used repeatably with good stability. The convenient preparation, effective separation and repeatability make this paper based separation channel SERS substrate have great potential application on the fast separation and simultaneous detection of various pesticides in complex field.

Advances in biosynthesis of noble metal nanoparticles mediated by photosynthetic organisms-A review

The last decade has witnessed significant developments in the biosynthesis of noble metal nanoparticles (NMNPs) due to their distinct advantages in various practical applications. Many photosynthetic organisms, including plants, microalgae, and photosynthetic bacteria, have been explored for NMNP synthesis in an eco-friendly and cost-effective manner. These biomasses were used for NMNP biosynthesis as growing cells, non-growing cells, whole cells extract, disrupted cell extract, residual biomasses, gum solutions, etc. Different mechanisms might be involved to reduce noble metal ions to NMNP. These mechanisms include reduction of metal ions catalysed by reductases using NADH as electron donors, reduction of metal ions using biochemical molecules such as polysaccharides and proteins as electron donators, and light-dependant biosynthesis of NMNP involving pigments for light capture and water-splitting for electron supplementation. NMNP may be applied as catalyst, antibacterial, anticancer, and drug delivery vehicle.

Phytochemical, in-vitro biological and chemo-preventive profiling of Arisaema jacquemontii Blume tuber extracts

Background

Arisaema jacquemontii is traditionally used in treatment of different diseases. In this study, phytochemical, in vitro biological and chemo-preventive screening of A. jacquemontii was carried out to explore its pharmacological potential.

Methods

The dried tuber of A. jacquemontii was extracted in 11 organic solvent mixture of different polarity. The extracts were screened for phytochemical assays (phenolics and flavonoids), antioxidants potential (free radical scavenging activity, total antioxidant activity, reducing power), biological activities (antibacterial, antifungal, cytotoxic, antileishmanial, protein kinase inhibition), and chemopreventive activities using different cell lines through standard protocols.

Results

Significant amount phenolic contents were determined in EtOH and MeOH extracts (210.3 ± 3.05 and 193.2 ± 3.15 μg GAE/mg, respectively). Maximum flavonoid content was determined in MeOH extract (22.4 ± 4.04 μg QE/mg). Noteworthy, DPPH scavenging activity was also recorded for MeOH extract (87.66%) followed by MeOH+EtOAc extract (85.11%). Considerable antioxidant capacity (7.8 ± 0.12 μg AAE/mg) and reducing power (3.1 ± 0.15 μg AAE/mg) was observed in extract of MeOH. The LC₅₀ against brine shrimp and leishmanial parasite was found 9.01 and 12.87 μg/mL for n-Hex and CHCl₃ extracts, respectively. The highest zone of inhibition against Streptomyces hyphae formation (12.5 ± 1.77 mm) by n-Hex extract. Growth zone of inhibition 13.8 ± 1.08 mm was recorded for EtOAc and MeOH extracts, respectively against Micrococcus luteus while 10.0 ± 0.11 mm for MeOH extract against Aspergillus flavus. In-vitro cytotoxic assay showed that n-Hex extract had higher cytotoxicity against DU-145 prostate cancer and HL-60 cancer cell lines. NF-kB and MTP potential showed 34.01 and 44.87 μg/mL for n-Hex and CHCl₃ extracts, respectively in chemo-preventive potential.

Conclusion

The study concludes that Arisaema jacquemontii bears significant phytochemical activity and pharmacological activities, this plant can be further explored for isolation of active component against a number of aliments.

Investigation of antioxidant, antibacterial, antidiabetic, and cytotoxicity potential of silver nanoparticles synthesized using the outer peel extract of Ananas comosus (L.)

Currently, green nanotechnology-based approaches using waste materials from food have been accepted as an environmentally friendly and cost-effective approach with various biomedical applications. In the current study, AgNPs were synthesized using the outer peel extract of the fruit Ananas comosus (AC), which is a food waste material. Characterization was done using UV–visible spectroscopy, X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, scanning electronic microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX) analyses. The formation of AgNPs has confirmed through UV–visible spectroscopy (at 485 nm) by the change of color owing to surface Plasmon resonance. Based on the XRD pattern, the crystalline property of AgNPs was established. The functional group existing in AC outer peel extract accountable for the reduction of Ag⁺ ion and the stabilization of AC-AgNPs was investigated through FT-IR. The morphological structures and elemental composition was determined by SEM and EDX analysis. With the growing application of AgNPs in biomedical perspectives, the biosynthesized AC-AgNPs were evaluated for their antioxidative, antidiabetic, and cytotoxic potential against HepG₂ cells along with their antibacterial potential. The results showed that AC-AgNPs are extremely effective with high antidiabetic potential at a very low concentration as well as it exhibited higher cytotoxic activity against the HepG₂ cancer cells in a dose-dependent manner. It also exhibited potential antioxidant activity and moderate antibacterial activity against the four tested foodborne pathogenic bacteria. Overall, the results highlight the effectiveness and potential applications of AC-AgNPs in biomedical fields such as in the treatment of acute illnesses as well as in drug formulation for treating various diseases such as cancer and diabetes. Further, it has applications in wound dressing or in treating bacterial related diseases.