Atranorin (ATR) is a lichenic secondary metabolite with potential uses in pharmacology. Antinociceptive and antiinflammatory actions have been reported, and the use of atranorin-enriched lichen extracts in folk medicine is widespread. Nonetheless, very few data on ATR biological actions are available. Here, we evaluated free radical scavenging activities and antioxidant potential of ATR using various in vitro assays for scavenging activity against hydroxyl radicals, hydrogen peroxide, superoxide radicals, and nitric oxide. The total reactive antioxidant potential (TRAP) and total antioxidant reactivity (TAR) indexes and in vitro lipoperoxidation were also evaluated. Besides, we determined the cytoprotective effect of ATR on H(2)O(2)-challenged SH-SY5Y cells by the MTT assay. ATR exerts differential effects towards reactive species production, enhancing hydrogen peroxide and nitric oxide production and acting as a superoxide scavenger; no activity toward hydroxyl radical production/scavenging was observed. Besides, TRAP/TAR analysis indicated that atranorin acts as a general antioxidant, although it demonstrated to enhance peroxyl radical-induced lipoperoxidation in vitro. ATR was not cytotoxic, and also protected SH-SY5Y cells against H(2)O(2)-induced cell viability impairment. Our results suggest that ATR has a relevant redox-active action, acting as a pro-oxidant or antioxidant agent depending on the radical. Also, it will exert cytoprotective effects on cells under oxidative stress induced by H(2)O(2).

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The acute study revealed no lethal effects at 300mg/kg of HERP, but toxic signs were observed, as HERP had an LD50 of more than 300mg/kg, indicating a warning. The most toxic signals in sub-acute studies were observed in males at a dose of 200mg/kg HERP. These results suggest estrogen-like activity, possibly from the isoflavones in HERP.

Citronellal (CT) is a monoterpenoid and the major constituent of the mixture of terpenoids that give the citronella oil its lemon scent. Citronella oil is widely used around the world for various purposes and is mainly obtained from plants of the Cymbopogon genus, which are known as "lemongrass." Considering these plants have been used worldwide for various medicinal purposes, the interest of researchers to understand the biological activities of monoterpenoids related to the Cymbopogon genus has been increasing. In the present work, we investigated the antinociceptive action and the redox properties of CT. Our results indicate that intraperitoneal injection of CT was effective in reducing nociceptive face-rubbing behavior in both phases of the formalin test, which was also naloxone-sensitive. CT also evoked antinociceptive response in the capsaicin and glutamate tests. The total radical-trapping antioxidant parameter and total antioxidant reactivity assays indicate that CT at doses of 0.1 and 1 mg/mL exerts a significant antioxidant activity, which is probably related to its ability to scavenge superoxide and nitric oxide, but not H(2)O(2) or hydroxyl radicals, as evaluated separately by specific in vitro tests. These results show for the first time the antinociceptive potential of CT and indicate that the antioxidant properties of this compound may rely on its mechanism of biological actions because CT-containing natural products are used to treat various diseases related to oxidative stress and reactive species.

Bauhinia belongs to the Caesalpinaceae, a plant family that comprises approximately 250 species.1) Native peoples from tropical regions use Bauhinia leaves and bark as medicine in infusions and other phytotherapic preparations. 2,3)Some native Bauhinia species in Brazil are known as "patade-vaca" (cow's hoof) and are widely used in folk medicine to treat various ailments, mainly infections and diabetes. Some reports have demonstrated positive effects on factors related to diseases and pathological states.2-5) Bauhinia microstachya (RADDI) MACBR. (Caesalpinaceae) is a creeper plant that occurs naturally in southern Brazil where is popularly known as "escada-de-macaco" (monkey's ladder). B. microstachya is often cultivated in small areas and its leaves are used as herbal antidiabetic medicine. Traditionally the leaf infusion or garrafada (a preparation with cachaça-the popular local sugar cane brandy-and leaves) is drunk after meals to help control blood sugar levels and other diabetic disorders. Phytochemical investigations with B. microstachya leaves have identified compounds such as steroidal glycosides, triterpenes, lactones and phenolic compounds, mainly flavonoids. [6][7][8] Plant phenolics form a large group of natural compounds, ubiquitous in the plant kingdom. It is known that these secondary metabolites display a remarkable array of biochemical interactions, probably due to antioxidant properties. 9)These substances may act as potent metal chelators and/or free radical scavengers, 10) however, it has been reported that the performance of these compounds in oxidative systems depends on activity-structure relationships.11,12) As an unfortunate consequence of aerobic life, free radicals and other reactive oxygen species (ROS) are formed by biological redox reactions.13) The role of free radicals reactions in biology and medicine has become an area of intense interest due to their relationship to chronic diseases.13) It is generally accepted that free radicals play an important role in the development of tissue damage and pathological events in living organisms.13) Lipids containing polyunsaturated fatty acids can be oxidized by free radical-mediated reactions. In addition, when oxygen is supplied in excess or their reduction is insufficient, this generates endogenous ROS imbalance with formation of hydroxyl ( · OH) and superoxide (O 2 · Ϫ ) radicals.13) In inflammation and endothelial damage, NO plays a major role as precursor of peroxynitrite (ONOO Ϫ ).14) If the endogenous response system, such as antioxidant enzymes superoxide dismutase (SOD) and catalase (CAT), is inadequate in scavenging ROS, damage to important macromolecules can be established and generate cellular oxidative stress.13) In addition, the non-enzymatic antioxidants (such as vitamin C, vitamin E and phenolic compounds found in a vegetable-rich diet) play a significant role in the physiological redox balance together with enzymatic defenses. 13)Considering the increasing interest in antioxidants, the potential antioxidant effects of pheno...