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ABSTRACT Allophylus edulis and Cupania vernalis (Sapindaceae) are Brazilian native trees used as medicinal plants for the treatment of respiratory, digestive, circulatory, and skin diseases. Ubiquitously distributed in the Brazilian territory, these species are indicated for mixed plantations aimed at the recovery of degraded ecosystems. In this study, the total phenolic content (TPC) and total flavonoid content (TFC), and the antioxidant activity of extracts and fractions obtained from A. edulis and C. vernalis leaves were assessed. The TPC and TFC was determined spectrophotometrically. Antioxidant activity was evaluated through radical scavenging activity of 2,2-diphenyl-1-picrylhydrazyl (DPPH). The extracts were obtained by two methods: maceration (method 1) and Soxhlet (method 2). Solvents of increasing polarity (hexane, dichloromethane, ethyl acetate, and n-butanol) were used to obtained the fractions. The results showed that the ethyl acetate fraction from A. edulis, obtained from the maceration method, had the highest TPC (442.0 ± 18.2 mg GAE g-1) and TFC (58.1 ± 0.4 mg RUE g-1), and antioxidant activity (EC50 = 43.6 ± 2.6 µg mL-1). By C. vernalis, superior results were obtained with the n-butanol fraction (TPC = 126.1 ± 5.8 mg GAE g-1, TFC = 37.7 ± 0.6 mg RUE g-1). The highest antioxidant potential was found in the crude hydroalcoholic extract (EC50 = 816.1 ± 50.9 µg mL-1) and butanol fraction (1,156.4 ± 3.8 µg mL-1). The results of this study show that the fractions obtained by maceration and liquid-liquid partition with more polar solvents (ethyl acetate and n-butanol) are the richest in TPC and TFC, and presented the greater antioxidant activity. Comparing the two plants, A. edulis showed the best results, with a high content of TPC, TFC, and antioxidant potential, and therefore may be used to treat diseases related to oxidative stress.

The marine phanerogam Syringodium filiforme, known as "manatee grass", is a common species that grows in coastal areas associated to Thalassia testudinum. With the aim to describe some of its possible chemical characteristics, this study was performed with a sample of 1.2 kg, collected in March 2009, in Guanabo beach, Havana, Cuba. The sample was dried (less than 12% humidity) and a total extract prepared; other three extracts were prepared with the use of solvents of increasing polarity. The phytochemical screening and analytical determinations of each fraction were undertaken Total polyphenol content was determined using pyrogallol as reference's standard; chlorophyll a and b and anthocyanin content were also quantified. Total extract and fractions antioxidant activity were evaluated by using the free radical scavenging activity assay with 1,1-Diphenyl-2-Picrylhydrazyl reactive (knowing as DPPH's method). The phytochemical screening of the different extracts detected the presence of high concentrations of flavonoids, phenols, terpenes, antocyanins, reducing sugars and alkaloids. The total extract and methanol fraction showed significant free radical scavenging properties, while the petroleum ether fraction showed moderate activity, and the chloroform fraction and the aqueous soluble precipitate (residual salt) obtained didn't show antioxidant properties against free radicals. The results of this work confirmed the potentialities of this species for biological purposes.

The prevalence of obesity has significantly increased during the last decades reaching epidemic proportions in many countries. Obesity has been described as a state of chronic oxidative stress. Furthermore, oxidative stress has been defined as the link between obesity and its major associated disorders such as insulin resistance, hypertension, etc. Because of this, recent studies have suggested the potential therapeutic role of dietary antioxidant supplementation in the reduction of body weight or its beneficial effect on several obesity related disorders. This review updates the data described during the last years (2002-2008) regarding the relationship between obesity and oxidative stress as well as the role of dietary antioxidant supplementation in the reduction of oxidative stress, obesity and its principal associated comorbidities. Despite the available data, here summarized, further studies are needed in order to deeply understand the molecular mechanisms involved in the beneficial effects of dietary antioxidants on obesity and associated disorders.

Unlabelled: The clinical potential of free radical (OFR) ablative therapy is dependent upon the proportion of the total injury caused by the reperfusion mechanism compared with the proportion resulting from ischemic injury itself. Prostaglandin cascade can both activate and be activated by OFR., Aim: to investigate the influence of different periods of cold ischemis in renal tissue (cortex and medulla) -regarding superoxide dismutase (S.O.D.) activity, the amount of erythrocyte trapping and prostaglandin synthesis. Also, to evaluate the effect of exogenous S.O.D. in the prevention of reperfusion injury., Material and Methods: 48 Lewis male rats (200-250 g) received renal isografts (RTx) preserved in Collins solution at 4 C for different periods: control group (8) non operated; group I (8) immediate RTx; group II (8) 12 hrs; group III (8) 18 hrs; group IV (8) 12 hrs+S.O.D. (13 mg/kg e.v.); group V (8) 18 hrs+S.O.D. (13 mg/kg e.v.). Before reperfusion all recipients received 1 ml of 51-Cr labelled erythrocytes. After 15 min. reperfusion grafts were removed and samples (cortex and medulla) obtained for measuring trapping of erythrocytes. S.O.D. activity and prostaglandins (PGe2, TxB2, 6-Keto-PGF1)., Results: A strong correlation was found between the duration of cold ischemia and the amount of trapping both in cortex and in medulla. S.O.D. administration induced a significant drop of trapping. In non-operated rats S.O.D. activity in cortex was two fold medulla content. However, after reperfusion, a significant decrease in cortex was found in all groups. S.O.D. administration raised S.O.D. activity in cortex similar to control values.(ABSTRACT TRUNCATED AT 250 WORDS)

The intestinal reperfusion injury has been studied in Sprague-Dawley rats weighing 200 g. Intestinal ischemia has been induced by clamping the Superior Mesenteric Artery (SMA) for 120 minutes. In order to parallel clinical situations, free radical scavengers (allopurinol [ALLO]) and superoxide-dismutase [SOD] were inoculated at a low perfusion rate through the femoral vein during the last 20 minutes of the ischemic period. Both drugs have decreased the mortality rate (from 70% in control group, to 40%) and the mean percentage of damaged intestine (30.89% vs. 23.84% and 24.70%). Histologically, ALLO was less effective than SOD (12.54 control; 8.40 SOD; 11.54 ALLO). The modification of glucose, SGOT, SGPT and LDH found in all the ischemic animals shows the hepatocellular injury induced by intestinal reperfusion.

This work studies the ischemic/reperfusion injury (I/R) in relationship to the production of free radicals from activated neutrophils. It is well known, that biochemical and physiopathological alterations participate in the tissue lesion produced by the interaction oxygen/leukocyte. Pharmacological manipulations, oriented to eliminate the harmful effect of the free radicals, remain as the most significant event in the management of the I/R injury. Compounds such as allopurinol, adenosine, naloxone, corticosteroids, methylurea, and others, have demonstrated a protective effect during the I/R injury. Although, the mechanism of action of these compounds is unknown, it is possible that the free radical scavenging effect, could be the most important protective mechanism. The better understanding of the I/R injury would allow for a better protection of the damaged organ.

Liver cirrhosis is a very common illnesses and currently its treatment remains unpromising. In a research line devoted to studying the hepatotoxicity of certain substances we have evaluated the lesions that appear prior to the occurrence of cirrhosis and hepatocarcinoma in order to test, in different assays liver-protecting substances such as cyanidanol-3 that have been seen to lead to an improvement in morphological alterations in the liver and even to reverse such lesions. The mechanisms of action of this compound are discussed. The authors believe that considerable work remains to be carried out but that some day some liver-protecting substances that yield good experimental results may be applied to clinical situations.