Antioxidant Activity: The Presence and Impact of Hydroxyl Groups in Small Molecules of Natural and Synthetic Origin

Polyhydroxylated natural phenolic compounds, especially those with low molecular weights, are characterized by their ability to eliminate free radicals as they act as strong antioxidants. The various types of phenolic compounds represent the most important natural antioxidants in addition to some vitamins. The chemical structures of these compounds is discussed in details with their action mechanisms to remove free radicals and prevent many incurable and malignant diseases. In addition to these natural compounds, the last two decades have witnessed increased attempts by many scientific groups and research centers to synthesize chemical compounds in large quantities to mimic these natural compounds, but at a lower cost and greater biological effectiveness. Herein, we conduct a chemical survey of relevant synthetic compounds containing the hydroxyl groups prepared in chemical laboratories and studied for their biological efficacies, such as their effectiveness as antioxidants, as well as the mechanism of elimination of free radicals

Different chemical behaviors and antioxidant activity of three novel schiff bases containing hydroxyl groups. X-ray structure of CH2{cyclo-C6H10-NH=CH-(2-O-naphth)}2.H2O

The antioxidant activities of three new Schiff base compounds, 1–3, were studied through their direct scavenging ability to eliminate free radicals using DPPH and ABTS methods and also through their indirect antioxidant activity as measured using the ferric thiocyanate (FTC) method. The number of OH groups in the compounds and their positions play a role in the activity. The crystal structure of CH2{cycloC6H10NHCH-(2-O-naphth)}2.H2O (1), has been determined and proves the existence of intramolecular hydrogen-bonds and hydrogen-bonded water molecules and reveals the keto-amine (NH⋯O) tautomer of this compound. One cyclo-hexyl ring was found to be disordered, and was resolved in two orientations. Hydrogen atoms of the NHCH groups were located in difference maps and were refined freely. Compounds 2 and 3 exhibit the enol-imine form. The UV–vis spectra of the three compounds have been studied in organic solvents of different polarity, and in basic and acidic media, and were found helpful in understanding the tautomeric forms in these compounds; the polarity was modified by adding (CF3COOH) or [(C2H5)3N] to the solvent. All three compounds have been characterized by elemental analysis, UV–vis, FTIR, NMR and MS

The Effectiveness of Using the Visual-Spatial Approach to Teach Physics on Developing Reflection Skills for Grade Ten Female Students, Al-Shamayatain District, Taiz Governorate

هدفت هذه الدراسة التعرف إلى فعالية استخدام المدخل البصري المكاني في تدريس الفيزياء في تنمية مهارات التفكير التأملي لدى طالبات الصف العاشر بمديرية (الشمايتين) بمحافظة تعز. ولتحقيق أهداف الدراسة قام الباحثان بإعداد دليل تدريس وحدة "القياسات الحرارية"، ووحدة "أثر الحرارة على الأجسام"، وفقًا للمدخل البصري المكاني، وتم بناء اختبار مهارات التفكير التأملي، وقد تكوّن بصورته النهائية من (24) فقرة من نوع (اختيار من متعدد)، بعد التأكد من صدقه وثباته، وطبق على عينة تكونت من (85) طالبة من طالبات مدرسة الخير – عزاعز – بطريقة قصدية، قُسمت إلى مجموعتين مجموعة تجريبية تكونت من (42) طالبة درسن الوحدتين بالمدخل البصري المكاني، ومجموعة ضابطة تكونت من (43) طالبة درسن نفس الوحدتين بالطريقة التقليدية المعتادة. وأظهرت النتائج وجود فروق دالة إحصائيًا عند مستوى دلالة (0.05=α) بين متوسطات درجات طالبات المجموعتين التجريبية والضابطة على اختبار مهارات التفكير التأملي في التطبيق البعدي، لصالح طالبات المجموعة التجريبية، وهو ما يعني تأثير تطبيق المدخل البصري المكاني على الطريقة العادية في تنمية مهارات التفكير التأملي لدى طالبات المجموعة التجريبية، كما كشفت النتائج عن وجود فروق دالة إحصائيًا بين متوسطات نتائج التطبيقين القبلي والبعدي على المجموعة التجريبية لصالح التطبيق البعدي. وفي ضوء النتائج قدم الباحثان عددًا من التوصيات والمقترحات، أهمها ضرورة استخدام المدخل البصري المكاني في تدريس الفيزياء بالمرحلة الثانوية، والعمل على تدريب مُعلمي الفيزياء على استخدام المدخل البصري المكاني في عملية التدريس. الكلمات المفتاحية: المدخل البصري المكاني، تدريس الفيزياء، مهارات التفكير التأملي.The aim of this study was to identify the effectiveness of using the Visual-Spatial Approach (VSA) to teach physics and its effect on reflection skills of Grade 10 female students, Al-Shamayatain District, Taiz Governorate. To achieve the aims of this study and according to the VSA, the researchers prepared a guide to teach two units from the book of Physics of Grade 10 which are “Thermometry” and “The Effect of Heat on Objects”. To examine the students’ reflection skills, the researchers prepared a test consisting of 24 multiple choice items; the test was checked for its validity and reliability. The test was administered to a purposive sample of 85 students at Al-Khair School, Aza’iz village. The students were divided into two groups: the experimental group which consisted of 42 students and the control group which consisted of 43 students. The participants of the experimental group were taught the two units using the VSA, whereas the participants of the control group were taught the same units using the traditional method. The results showed that there were significant statistical differences at the level (α = 0.05) between the average scores of the two groups, in favor of the experimental group. This indicated that the VSA approach has an effect on reflection skills compared to the traditional one. Furthermore, the results showed that there were significant statistical differences between the average results of pre and posttests, in favor of the post test administered to the experimental group. Based on these results, it is recommended that the Visual-Spatial Approach be used to teach physics for secondary school students. It is also advised that Physics’ teachers should be trained to use this approach in teaching. Keywords: Visual-spatial approach, Teaching of physics, Reflection skills

Localised Skin Hyperpigmentation as a Presenting Symptom of Vitamin B12 Deficiency Complicating Chronic Atrophic Gastritis

Vitamin B12 deficiency is common in developing countries and should be suspected in patients with unexplained anaemia or neurological symptoms. Dermatological manifestations associated with this deficiency include skin hyper- or hypopigmentation, angular stomatitis and hair changes. We report a case of a 28-year-old man who presented to the Sultan Qaboos University Hospital in Muscat, Oman, in November 2013 with localised hyperpigmentation of the palmar and dorsal aspects of both hands of two months’ duration. Other symptoms included numbness of the hands, anorexia, weight loss, dizziness, fatigability and a sore mouth and tongue. There was no evidence of hypocortisolaemia and a literature search revealed a possible B12 deficiency. The patient had low serum B12 levels and megaloblastic anaemia. An intrinsic factor antibody test was negative. A gastric biopsy revealed chronic gastritis. After B12 supplementation, the patient’s symptoms resolved. Family physicians should familiarise themselves with atypical presentations of B12 deficiency. Many symptoms of this deficiency are reversible if detected and treated early

Synthesis of Chalcones with Anticancer Activities

Several chalcones were synthesized and their<em> in vitro </em>cytotoxicity against various human cell lines, including human breast adenocarcinoma cell line MCF-7, human lung adenocarcinoma cell line A549, human prostate cancer cell line PC3, human adenocarcinoma cell line HT-29 (colorectal cancer) and human<strong> </strong>normal liver cell line WRL-68 was evaluated. Most of the compounds being active cytotoxic agents, four of them with minimal IC<sub>50</sub> values were chosen and studied in detail with MCF-7 cells. The compounds <strong>1</strong>, <strong>5</strong>, <strong>23</strong>, and <strong>25</strong> were capable in eliciting apoptosis in MCF-7 cells as shown by multiparameter cytotoxicity assay and caspase-3/7, -8, and -9 activities (<em>p</em> < 0.05). The ROS level showed 1.3-fold increase (<em>p</em> < 0.05) at the low concentrations used and thus it was concluded that the compounds increased the ROS level eventually leading to apoptosis in MCF-7 cells through intrinsic as well as extrinsic pathways

Toxicological features of catha edulis (Khat) on livers and kidneys of male and female sprague-dawley rats: a subchronic study

Hepato- and nephrotoxicity of Khat consumption (Catha edulis Forskal) have been evoked. Therefore, this study was conducted to evaluate such possible hepatorenal toxicity in female and male Sprague-Dawley rats (SD rats) focusing primarily on liver and kidney. In addition, female and male rats were investigated separately. Accordingly, forty-eight SD-rats (100-120 g) were distributed randomly into four groups of males and female (n = 12). Normal controls (NCs) received distilled water, whereas test groups received 500 mg/kg (low dose (LD)), 1000 mg/kg (medium dose (MD)), or 2000 mg/kg (high dose (HD)) of crude extract of Catha edulis orally for 4 weeks. Then, physical, biochemical, hematological, and histological parameters were analyzed. Results in Khat-fed rats showed hepatic enlargement, abnormal findings in serum aspartate aminotransferase (AST), and alkaline phosphatase (ALP) of male and female SD-rats and serum albumin (A) and serum creatinine (Cr) of female as compared to controls. In addition, histopathological abnormalities confirmed hepatic and renal toxicities of Khat that were related to heavy Khat consumption. In summary, Khat could be associated with hepatic hypertrophy and hepatotoxicity in male and female SD-rats and nephrotoxicity only in female SD-rats