ABSTRACT
Objective: To develop a new method for the determination of anti-oxidant activity of drugs by using the peroxidase activity of graphene nanoenzyme, and apply it for the determination of the anti-oxidant activity of the national medicine Achnatherum inebrians. Methods: The anti-oxidant activity of 18 batches of samples was measured after optimizing H2O2 concentration and reaction time. At the same time, the anti-oxidative activity was measured again using the DPPH method. The Bland-Altman and Passing-Bablok regression methods were used to compare the detection data of the two methods. Results: Using the nanoenzyme method, the inhibition rates of 18 batches of A. inebrians were between 37.28% and 71.58%, with an average of 50.87% and a median of 47.09%. Free radical scavenging rates of 18 batches of A. inebrians measured by the DPPH method were between 36.06% and 83.11%, with an average of 54.89% and a median of 50.83%. The statistical results showed that the measured values of nanoenzyme method and DPPH method were similar; There was a linear relationship between the two methods, and different methods can be transformed by Passing-Bablok regression method. Conclusion: The graphene nanoenzyme was successfully applied to the detection of anti-oxidant activity, and the anti-oxidant activity of A. inebrians was also found. The nanoenzyme method can avoid the problem of light sensitivity of the reagent, shorten the reaction time, reduce the amount of medicinal solution, and the results are consistent with the DPPH method, which is suitable for the determination of antioxidant activity.
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Objective: To develop a novel method to synthesize silver nanoparticles (AgNPs) by using the extract of Yinqiao Jiedu Mixture waste, evaluate the effects of biosynthesis parameters on the formation and polydispersity of AgNPs, and investigate the antioxidative and antibacterial activity. Methods: The formation of AgNPs was confirmed by UV-visible spectroscopy; The size, polydispersity, surface and morphology features of AgNPs were characterized by laser granularity analyzer and transmission electron microscopy; The antioxidative and antibacterial activities of AgNPs were evaluated by calculating the scavenging rate for DPPH and A600 for both Escherichia coli and Staphylococcus aureus, respectively. Results: By using Yinqiao Jiedu Mixture waste, the AgNPs could be prepared at ambient temperature. The size and polydispersity index of the synthesized AgNPs were sensitive to the biosynthesis parameters, such as pH of extract and material proportion with the average size distribution was 14.2-94.8 nm, offering a size-controlled synthetic method for AgNPs. And when the pH was 6.0, the polydispersity could reach the best. The AgNPs could be obtained with high yield and small size at pH 10.0, material proportion 3:1 after reacting 2 h, which were quasi-spherical in shape with average size of (24.0 ± 0.3) nm and covered by anion [Zeta potential: (-23.1 ± 0.2) mV]. The synthesized AgNPs also revealed significant inhibition activities for the growth of E. coli and S. aureus with MIC 50.0 and 25.0 μg/mL, respectively, and potent antioxidative activity with scavenging rate for DPPH 71.1% when adding 100 μg/mL of AgNPs. Conclusion: The extract of Yinqiao Jiedu Mixture waste can be used to synthesize AgNPs with small size at ambient temperature; The biosynthesis parameters have significant effects on the average size and polydispersity index of AgNPs; The synthesized AgNPs have potent antioxidative and antibacterial activity.
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Streptomyces from rare ecosystems is the promising source for secondary metabolites exhibiting diverse biological activities. The present study reports the antioxidant activity and antimicrobial activity against biofilm forming bacteria by the pigment produced from Desert soil Streptomyces sp. D25. Crude pigment from the Streptomyces sp D25 was produced by agar surface fermentation using yeast extract malt extract agar and extracted using ethyl acetate. Antioxidant activity of pigment was tested at 100-500μg/ml concentration by DPPH and nitric acid scavenging assay. Antimicrobial activity against the biofilm forming bacteria was tested by disc diffusion method. The Streptomyces pigment showed 35.63% and 96.19% free radical scavenging activity in DPPH assay and nitric oxide assay, respectively. The results of radical scavenging activity of pigment in DPPH and nitric oxide assay showed its antioxidant potential. In antimicrobial assay, the pigment showed 10-20 mm inhibition against biofilm forming bacteria at 25μg/ml. Further in vivo studies on this Streptomyces pigment pave the way for its biomedical applications.
ABSTRACT
Objective: Five phenolic compounds in fruits of Rhodomyrtus tomentosa from six different regiones were measured by HPLC, and the ability of scavenging free radicals of five kinds of phenolics and myrtle fruits extracts in different regions was investigated. Methods: The determination was performed on Inertsil ODS-SP column (150 mm × 4.6 mm, 5 μm), the mobile phase consisted of acetonitrile and 0.1% phosphate aqueous solution with gradient elution program, flow rate was 1 mL/min with 10 μL of sample quantity at 280 nm, and the antiradical efficiency of five phenolic compounds and extrcts were evaluated by DPPH radical scavenging assay. Results: Five kinds of phenolic components showed a good linear relationship, and the precision, stability, repeatability, and sample recovery rate all met the requirements. Five phenolic compounds and extracts had good antiradical efficiency. The IC50 values of the myrtle fruits extracts from Xinfeng, Wengyuan counties in Guangdong province, Nanning, Guilin in Guangxi province, Yunnan province, and Guizhou province were 58.82, 61.57, 17.73, 7.91, 14.77, and 8.11 μg/mL, and the IC50 values of gallic acid, protocatechuic acid, catechin, ellagic acid, and resveratrol were 0.02, 0.04, 0.03, 0.05, and 5.70 μg/mL, respectively. The IC50 of positive control VC was 6.31 μg/mL. Conclusion: Material basis of antiradical efficiency of fruits is preliminary identified and it provides a scientific basis for the comprehensive utilization of the resources of R. tomentosa.