Green Synthesis of Silver Nanoparticles Using Pomegranate and Orange Peel Extracts and Their Antifungal Activity against Alternaria solani, the Causal Agent of Early Blight Disease of Tomato

This study aimed to synthesize silver nanoparticles (AgNPs) by pomegranate and orange peel extracts using a low concentration of AgNO3 solution to controlearly blight of tomato caused by Alternaria solani. The pathogen was isolated from infected tomato plants growing in different areas of Saudi Arabia. The isolates of this pathogen were morphologically and molecularly identified. Extracts from peels of pomegranate and orange fruits effectively developed a simple, quick, eco-friendly and economical method through a synthesis of AgNPs as antifungal agents against A. solani. Phenolic content in the pomegranate peel extract was greater than orange peel extract. Phenolic compounds showed a variation of both peel extracts as identified and quantified by High-Performance Liquid Chromatography. The phenolic composition displayed variability as the pomegranate peel extract exhibited an exorbitant amount of Quercitrin (23.62 mg/g DW), while orange peel extract recorded a high amount of Chlorogenic acid (5.92 mg/g DW). Biosynthesized AgNPs were characterized using UV- visible spectroscopy which recorded an average wavelength of 437 nm and 450 nm for pomegranate and orange peels, respectively. Fourier-transform infrared spectroscopy exhibited 32x73.24, 2223.71, 2047.29 and 1972.46 cm−1, and 3260.70, 1634.62, 1376.62 and 1243.76 cm−1 for pomegranate and orange peels, respectively. Transmission electron microscopy showed spherical shape of nanoparticles. Zetasizer analysis presented negative charge values; −16.9 and −19.5 mV with average particle sizes 8 and 14 nm fin case of pomegranate and orange peels, respectively. In vitro, antifungal assay was done to estimate the possibility of biosynthesized AgNPs and crude extracts of fruit peels to reduce the mycelial growth of A. solani. AgNPs displayed more fungal mycelial inhibition than crude extracts of two peels and AgNO3. We recommend the use of AgNPs synthesized from fruit peels for controlling fungal plant pathogens and may be applied broadly and safely in place by using the chemical fungicides, which display high toxicity for humans.

EFEKTIVITAS PESTISIDA ORGANIK EKSTRAK KULIT JERUK NIPIS TERHADAP KEMATIAN JANGKRIK

Pestisida organik adalah pestisida yang bahan dasarnya berasal dari tumbuhan yang bersifat mudah terurai di alam. Salah satu tumbuhan yang dapat dijadikan bahan baku pembuatan pestisida organik adalah kulit jeruk nipis. Kulit jeruk dapat berpotensi menjadi repellent karena mengandung minyak atsiri dengan komponen limonene, mirsen, linalool, oktanal, decanal, sitronelol, neral, geraniol, valensen dan sinensial. Linalool, sitronelol dan geraniol termasuk senyawa yang bersifat repellent terhadap serangga (arthropoda). Pengunaan bahan alami dari ekstrak kulit jeruk diharapkan lebih aman jika dibandingkan dengan bahan kimia Dichloro Diphenyl Trichloroethane (DDT). Proses pembuatan pestisida organik dilakukan dengan ekstraksi maserasi menggunakan ethanol sebagai pelarut. Dalam penelitian ini bertujuan untuk mengetahui pengaruh variabel terhadap hasil pengujian pestisida organic terhadap jangkrik. Hasil penelitian menunjukkan pada konsentrasi pestisida organic 5% didapatkan prosentase kematian jangkrik 72%, pada konsentrasi 15% didapatkan prosen kematian jangkrik 80%, dan pada konsentrasi 25% didapatkan prosen kematian jangkrik 88%. Hasil penelitian menunjukkan bahwa adanya pengaruh terhadap perbedaan konsentrasi pestisida organic terhadap kematian jangkrik. Kata kunci: jeruk nipis, maserasi, pestisida organik AbstractOrganic pesticides are pesticides whose basic ingredients come from plants that are easily biodegradable in nature. One of the plants that can be used as raw material for making organic pesticides is lime peel. Orange peel can potentially be a repellent because it contains essential oils with components of limonene, mirsen, linalool, octanal, decanal, citronellol, neral, geraniol, valensen and sinensial. Linalool, citronellol and geraniol are compounds that are repellent to insects (arthropoda). The use of natural ingredients from orange peel extract is expected to be safer when compared to the chemical Dichloro Diphenyl Trichloroethane (DDT). The process of making organic pesticides is done by maceration extraction using ethanol as a solvent. This study aims to determine the effect of variables on the results of testing organic pesticides on crickets. The results showed that at 5% organic pesticide concentration, 72% of crickets died, at 15%, 80% of crickets died, and at 25%, 88% of crickets died. The results showed that there was an effect on differences in the concentration of organic pesticides on the mortality of crickets.. Keywords: lime, maceration, organic pesticide

Orange Peel Extract Mediated Silver Nanofluid as Corrosion Inhibitor for X80 Steel in Simulated Oilfield Scale Dissolver

Silver nanofluid was prepared by bio-reduction reaction between orange peels extracts (OPE) and silver nitrate and characterized by spectroscopic and microscopic techniques. Colloidal nanoparticles of sizes between 40 – 50 nm and spherical shape were obtained. The nanofluid was applied as anticorrosion additive to inhibit corrosion of X80 steel in simulated oilfield scale dissolver solution (1.0 M HCl) at various temperatures. The nanofluid (OPE-AgNPs) was 98.9 % and 84.3 % efficient at 30 ºC and 60 oC respectively as determined by weight loss measurement. In comparison with OPE, OPE-AgNPs shows better corrosion inhibition and higher resistance to thermal degradation. Some kinetic and thermodynamic models were used to characterize the inhibition process. OPE-AgNPs could be optimized and used as alternative anticorrosion additive for scale dissolution liquor in the industry.

Biosynthesis of Silver Nanoparticles Using Orange Peel Extract for Application in Catalytic Degradation of Methylene Blue Dye

Interest in the biosynthesis of silver nanoparticles (AgNPs) has been steadily increasing primarily due to their numerous applications in various fields, low-cost, use of non-toxic environmentally-friendly materials and easy implementation. This study focused on the biosynthesis of AgNPs using orange peel extract (OPE), optimization of process conditions, and application in catalytic degradation of methylene blue (MB) dye used in the textile industry. A central composite design in response surface methodology resulted in optimum conditions of 0.0075 g dry peel/mL for OPE concentration, pH of 11 and 1.5 mM silver nitrate concentration. The optimum conditions for the response variables corresponded to the peak absorbance of 0.79 and SPR wavelength of 403.8 nm in UV-vis spectra, and minimum particle size of 12.9 nm. In addition, peak absorbance and SPR wavelength appeared to be related to the size of the AgNPs. A full-factorial design for the catalytic degradation of MB dye by the biosynthesized AgNPs for 1 h indicated the maximum influence of AgNPs compared to the concentrations of MB dye and NaBH4 in decreasing order. The MB dye was reduced rapidly with NaBH4 in the presence of AgNPs due to their catalytic action. The findings of the study show the potential of OPE for the biosynthesis of AgNPs with excellent catalytic activity for the treatment of MB dye in industrial effluent.

Postprandial Bioactivity of a Spread Cheese Enriched with Mountain Tea and Orange Peel Extract in Plasma Oxidative Stress Status, Serum Lipids and Glucose Levels: An Interventional Study in Healthy Adults

Postprandial lipemia, glycemia and oxidative stress may affect the occurrence of cardiovascular disease. The purpose of the present intervention study was to investigate the effect of a spread cheese enriched with mountain tea (Sideritis sp.) and orange peel (Citrus sinensis) extract on postprandial metabolic biomarkers in healthy volunteers. In a cross-over design, 14 healthy subjects 20–30 years old were consumed either a meal rich in fat and carbohydrates (80 g white bread, 40 g butter and 30 g full fat spread cheese) or a meal with the spread cheese enriched with 6% mountain tea–orange peel extract. Differences in postprandial total plasma antioxidant capacity, resistance of plasma to oxidation, serum lipids, glucose and uric acid levels were evaluated at 0, 1.5 and 3 h after consumption. Plasma total antioxidant capacity was significantly increased 3 h after the consumption of the meal in the presence of the extract-enriched cheese, compared to the conventional cheese (p = 0.05). Plasma resistance to oxidation was increased at 30 min in the Functional meal compared with the Control meal. A tendency to decrease the postprandial rise in glucose and triglyceride levels, 1.5 h and 3 h, respectively, after the intake of the meal with the extract-enriched cheese was observed (p = 0.062). No significant changes in the concentrations of the remaining biomarkers studied were observed (p > 0.05). Further studies with a larger sample are needed in both healthy adults and patients with cardiovascular disease to draw safer conclusions about the postprandial effect of the extracts on metabolic biomarkers that predict cardiovascular risk.

Orange peel extract reduces the inflammatory state of skeletal muscle after downhill running via an increase in IL-1RA

It has been reported that orange peel extract (OPE) and the four major polymethoxyflavones (PMFs) in OPE have a protective effect against downhill running (DR)-induced skeletal muscle inflammation. However, the mechanism is not well understood. We investigated the potential of OPE and PMF compounds for increasing anti-inflammatory cytokine levels. The plasma interleukin-1 receptor antagonist (IL-1RA) level was increased 1 and 8 h after OPE administration in rats. Nobiletin induced the secretion of IL-1RA from C2C12 myotubes. In the inflammatory state of skeletal muscle after DR, OPE administration reduced nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) expression, NF-κB-DNA binding, and monocyte chemotactic protein-1 mRNA levels, but these effects were all abrogated by the intravenous administration of IL-1RA neutralizing antibody. These results indicated that OPE reduces skeletal muscle inflammatory state after DR via an increase in IL-1RA, and that IL-1 receptor signaling is important for skeletal muscle inflammation after DR.