نتایج جستجو برای: روش تیتراسیون dpph

تعداد نتایج: 378589  

2006
Kriengsak Thaipong Unaroj Boonprakob Kevin Crosby Luis Cisneros-Zevallos David Hawkins Byrne

Guava fruit extracts were analyzed for antioxidant activity measured in methanol extract (AOAM), antioxidant activity measured in dichloromethane extract (AOAD), ascorbic acid, total phenolics, and total carotenoids contents. The ABTS, DPPH, and FRAP assays were used for determining both AOAM and AOAD, whereas the ORAC was used for determining only AOAM. Averaged AOAM [mM Trolox equivalent (TE)...

2013
Boris M. Popović Dubravka Štajner Anamarija Mandić Jasna Čanadanović-Brunet Slavko Kevrešan

Serbian soybean genotype Ana was gamma irradiated at doses of 1, 2, 4, and 10 kGy in order to evaluate the influence of gamma irradiation on isoflavone (genistein, daidzein, and their glycosides genistin and daidzin) contents and hydroxyl radical scavenging effect (HRSE). The increase in genistin and daidzin contents as well as antioxidant activities was observed especially at doses of 4 and 10...

2015
Gang Wang Shun Yao Xiu-Xiu Zhang Hang Song

2,2-Diphenyl-1-picrylhydrazyl-ultra-high performance liquid chromatography-Q-time-of-flight mass spectrometry (DPPH-UPLC-Q-TOF/MS), as a rapid and efficient means, now was used for the first time to screen antioxidants from Selaginella doederleinii. The nine biflavone compounds were screened as potential antioxidants. The biflavones were structurally identified and divided into the three types,...

2015
Lingzhi Li Ying Peng Chong Hu Chunting Liu Qingbo Liu Linguang Li Jie Wu Shaojiang Song

Phytochemical investigation of the aqueous extract of Pithecellobium clypearia afforded one novel compound, clypearoside A (1), and one new stereoisomer, (-)-(2S,3S)-epigallocatechin-7-gallate (2) and four known ones (3-6). Their structures were elucidated on the basis of spectroscopic data, especially 2D NMR, HRESIMS and ECD spectra. Compounds 2-4 showed strong activity against DPPH (diphenylp...

Journal: :Bangladesh Medical Research Council bulletin 2012
M M Hossain M M Hossain M H Muhib M R Mia S Kumar S A Wadud

In continuation of our study the in vitro antioxidant activity of some novel quinoxaline derivatives was investigated by 1,1-diphenyl-2-picrylhydrazyl (DPPH) method with respect to ascorbic acid. To determine the antioxidant activity, a number of substituted indoxyls (3A-G), cyclic ketones (2A-G), and quinoxalines (1A-G) were synthesized by both microwave and conventional heating methods. The p...

2015
Puteri Amelia Berna Elya Muhammad Hanafi

A xanthone, 1,3,6,7-tetrahydroxy-xanthone (compound (1)) had been isolated from Garcinia benthami Pierre. The isolation was conducted through the chromatography technique and spectroscopy methods by spectroscophyc: mass spectrometry (LC-MS), infra red (IR), UV, 1H-NMR, 13C-NMR (1D and 2D-NMR). Antioxidant activity test by using DPPH (1,1diphenyl-2-picrylhydrazyl) method from the isolated compou...

Journal: :BMC Complementary and Alternative Medicine 2001
Mark JS Miller Fausto M Angeles Brian K Reuter Paul Bobrowski Manuel Sandoval

BACKGROUND The potential of ascorbic acid and two botanical decoctions, green tea and cat's claw, to limit cell death in response to oxidants were evaluated in vitro. METHODS Cultured human gastric epithelial cells (AGS) or murine small intestinal epithelial cells (IEC-18) were exposed to oxidants - DPPH (3 microM), H2O2 (50 microM), peroxynitrite (300 microM) - followed by incubation for 24 ...

Journal: : 2022

هدف: پژوهش حاضر با هدف ساخت برنامه داربست‌سازی انگیزشی و تعیین اثربخشی آن بر جهت‌گیری‌های هدفی ارزیابی‌های شناختیوالدین انجام شد. روش: پس از طراحی آموزشی داربست سازی اساس نقشه نگاری مداخله، به منظور بررسی شبه‌آزمایشی طرح پیش‌آزمون ـ پس‌آزمون همراه پیگیری گروه گواه استفاده جامعه آماری شامل تمامی والدین ­دانش‌آموزان پایه هشتم منطقة 4 آموزش پرورش شهر تهران نمونة نیز 30 مادر دارای فرزند کلاس هفتم ب...

Journal: : 2022

هدف: آینده­ نگری مجموعه ­ای از توانایی­ های شناختی است. که شامل پیش­ بینی حالت­ ممکن آینده و نیازهای خود این مهارت برای برنامه­ ریزی، غلبه بر موانع رسیدن به موفقیت افراد کمک می­کند. یکی جدیدترین ابزارهای سنجش توانایی تفکر آینده­نگر در کودکان، مقیاس کودکان (مازاچووسکای مهی، 2020) است ویژگی­ روان­سنجی آن استفاده جمعیت ایرانی مورد مطالعه قرار نگرفته روش: روش پژوهش حاضر توصیفی مقطعی بود. تعداد 200 ...

2014
In Ho Yeo Cham Kyul Lee Eun Yong Lee

OBJECTIVES The objective of this study is to investigate the effects of Salviae Miltiorrhizae Radix hot aqueous extract on nitric oxide (NO) and prostaglandin E2 (PGE2 ) production and on 1,1-diphenyl-2-picryl hydrazyl (DPPH) free-radical scavenging in macrophages. METHODS Salviae Miltiorrhizae Radix(300 g) was heated at 100℃ with distilled water (2 L) for 4 hours. The extract was filtered an...

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