پتانسیل آنتی‌اکسیدانی نانو اکسیدسریم سنتز شده از ماکروجلبک sargassum ilicifolium و ستاره‌ی شکننده گونه‌ ophiocoma scolopendrina

امروزه نانوتکنولوژی تقریباً در تمام حوزه‌های علمی و تکنیکی نفوذ کرده است. این مطالعه سنتز سبز نانوذرات اکسیدسریم با استفاده از عصاره‌های طبیعی دریایی ماکروجلبک sargassum ilicifolium و ستاره شکننده scolopendrina ophiocoma را مورد بررسی قرار داد. ترکیبات موجود در عصاره‌های دریایی می‌توانند به‌عنوان عوامل کاهنده و تثبیت کننده برای یون‎های سریم عمل کنند. انتقال اکسیداسیون بین یون‎هایce3+ وce4+ به‎‌طور همزمان منجر به محصول نانوذرات‌های سریم اکساید می‌شود. پیک‌های مشخصه برای ceo2 با طیف پراش اشعه ایکس به صفحات کریستالی (111)، (200)، (220)،‌ (311) ، (331)، (420) و (422) مربوط می‌شوند. در تصاویرsem نانوذرات اکسیدسریم سنتز شده به‎طور کلی شکل کروی با اندازه حدود 10 تا 12 نانومتر دارند، همچنین تجزیه و تحلیل ftir حاکی از وجود قله‌های برجسته‎ای بود که حضور این نانوذره را نشان داد. حالت‌های ظرفیتی متفاوت ce3+ وce4+ روی سطح نانوسریم به‎عنوان یک آنتی‌اکسیدان عمل می‌کند. نانوذره‌ی سنتز شده از جلبک در غلظت‌های 1000، 500 و 250 میکروگرم بر میلی‌لیتر بین 60-65 درصد مهار رادیکال آزاد dpph را نشان داد . بالاترین میزان احیاکنندگی ماکروجلبک s. ilicifolium در غلظت 500 میکروگرم بر میلی‌لیتر که اختلاف معنی‌داری با نانو ذرات سنتز شده از عصاره‌ جانوری موجود و غلظت‌های مختلف مورد آزمایش مشاهده گردید (0.05 ≥p)فعالیت ضدباکتریایی نشان داد که باکتری‌گرم منفی نسبت به باکتری‌ گرم مثبت در برابر نانوذرات ceo2 مقاوم‌تر است.

antioxidant potential of nano cerium oxide synthesized from macroalgae ( sargassum ilicifolium ) and brittle star (ophiocoma scolopendrina )

this study investigated the green synthesis of cerium oxide nanoparticles using natural marine extracts. characteristic peaks for ceo2 with x-ray diffraction spectrum to crystal planes (111), (200), (220) (311), (331), (420), and ( 422) are related. in the sem images, the synthesized cerium oxide nanoparticles are generally spherical with a size of about 10 to 12 nm. the ftir analysis indicated the presence of prominent peaks that showed the presence of this nanoparticle in different capacity states of ce +3, ce4+ acts as an antioxidant on the surface of nano cerium. nanoparticles synthesized from algae at concentrations of 1000, 500, and 250 µg /ml showed between 60-65% dpph free radical inhibition. the highest reduction rate of macroalgae sargassum ilicifolium at a concentration of 500 µg /ml, it is a significant difference between nanoparticles synthesized from the available extracts and tested at different concentrations. antibacterial activity was observed (p≤0.05). it showed that gram-negative bacteria are more resistant to ceo2 nanoparticles than gram-positive bacteria. introductiontoday, biological methods of nanoparticle synthesis using microorganisms, natural extracts, and nutrients have been suggested as suitable alternatives to chemical and physical methods (das et al., 2013). researchers have reported that cerium nanoparticles are effective in dealing with oxidative stress and have an antioxidant role, so these nanoparticles can act as a remover of various forms of reactive oxygen in many physiological and biochemical reactions in the body of living organisms (dhall et al. al., 2017(. microalgae are the main group of photoautotrophic organisms known as potential sources of secondary metabolites, phenolic compounds, pigments and polysaccharides. biosynthesis targets algal secondary metabolites as reducing agents for stabilization of nanoparticles (nps) (barciela et al., 2022). metabolites extracted from starfish with low molecular weight have remarkable characteristics. these isolated compounds include steroids, anthroquinones, alkaloids, phospholipids and peptides, which are a rich source of activity against microbes and have many uses in the field of medicine (baharara et al., 2020). in this study, the antioxidant and antibacterial properties of green cerium oxide nanoparticles synthesized from marine extracts have been investigated. materials and methods sargassum ilicifolium macroalgae was collected from the coast of chabahar and transported to the laboratory. then the samples were washed several times with distilled water in order to separate the mud and dried in the shade and at a suitable temperature for a week and then ground to powder. brittle star ophiocoma scolopendrina was collected from qeshm island at the time of low tide and dried with a freeze dryer at -40c and then powdered with an industrial mill. in order to extract and synthesize ceo2nps nano cerium oxide, 10 grams of powdered each of the samples was added to 100 ml of double distilled water and stirred for 3 to 4 hours at 60 degrees celsius, then it was collected with filter paper and then whitman. in an erlenmeyer flask, 100 ml of 0.05 m of ce(no3)3.6h2o and 20 ml of distilled water were added to it and this solution was stirred using a magnetic stirrer until a homogeneous solution was formed (altaf et al. al., 2021). then 40 ml of the extract was added to the solution and the final volume was brought to 100 ml with distilled water and the reaction mixture was stirred on a hot magnetic plate with a temperature of 70-80 degrees celsius for 3-4 hours. the formed particles after sufficient stirring time were centrifuged at 5000 rpm for 10 minutes, the nanoparticles were repeatedly washed with deionized water and dried in an oven at 60 degrees for 6 hours. then, the obtained product was calcined in the oven at 400°c for 2 hours to produce a yellow powder of cerium oxide (elahi et al., 2019). in the test of measuring the antioxidant capacity by the dpph (2,2-diphenyl-1-picrylhydrazyl) radical method, concentrations of 1000, 500, 125, 250, 62.5 and 31.25 μg/ml were made from 10 mg/ml stock, from 100 μl of each concentration was taken and poured into 96-well plates in triplicate. also, 100 microliters of 0.3 mm dpph solution (394.3 g/mol) was added. the 96-well plates were placed in the dark for 30 minutes, and the absorbance of the samples was read by an elizarider device at a wavelength of 517 nm. results in the ft-ir study, the peaks around 1417, 1575, and 1577, 1432 cm2 in samples a and b are related to carbonate compounds. scanning electron microscopy (sem) has shown that the nanoparticles are spherical and tend to aggregate.the highest reduction rate against ascorbic acid was observed in sargassum macroalgae at a concentration of 500 μg/ml. discussion and conclusion the highest inhibitory activity of nps synthesized for s. ilicifolium was observed (65.45 ± 0.5% at 1000 μg/ml). the basis of the biological activities of cerium nanoparticles is the ce3+/ce4+ surface ratio, the cycle of oxidation and reduction between the ce3+ and ce4+ states, which have a unique ability to absorb and release oxygen on their surface and play a key role in antioxidant activity (dhall and self, 2018).