Structural Elucidation and Free Radical Scavenging Activity of a new o-Orsellinic Acid Derivative Isolated from the Lichen Cladonia rappii.

Rappiidic acid, a new o-orsellinic acid derivative, was isolated from the lichen Cladonia rappii. Its capability to scavenge reactive oxygen species (ROS) and reactive nitrogen species (RNS) was investigated and compared with resveratrol and (+)-usnic acid. Usnic acid at 100 µM was the most efficient ROS scavenger, exhibiting activity 3-fold higher than that of resveratrol. At the same concentration, rappidic acid scavenged 23.1% of ROS formed, demonstrating that this compound is twice as active as resveratrol. Both compounds were shown to be poor RNS scavengers.

An overview on the potential of natural products as ureases inhibitors: A review.

Ureases, enzymes that catalyze urea hydrolysis, have received considerable attention for their impact on living organisms' health and life quality. On the one hand, the persistence of urease activity in human and animal cells can be the cause of some diseases and pathogen infections. On the other hand, food production can be negatively affected by ureases of soil microbiota that, in turn, lead to losses of nitrogenous nutrients in fields supplemented with urea as fertilizer. In this context, nature has proven to be a rich resource of natural products bearing a variety of scaffolds that decrease the ureolytic activity of ureases from different organisms. Therefore, this work compiles the state-of-the-art researches focused on the potential of plant natural products (present in extracts or as pure compounds) as urease inhibitors of clinical and/or agricultural interests. Emphasis is given to ureases of Helicobacter pylori, Canavalia ensiformis and soil microbiota although the active site of this class of hydrolases is conserved among living organisms.

Organ-coordinated response of early post-germination mahogany seedlings to drought.

Water deficit tolerance during post-germination stages is critical for seedling recruitment. In this work, we studied the effect of water deficit on morphological and biochemical responses in different organs of newly germinated mahogany (Swietenia macrophylla King) seedlings, a woody species that occurs in the Amazon rainforest. The root : shoot ratio increased under water deficit. The leaf number and water potential were not altered, although reductions in leaf area and stomatal conductance were observed. Osmotic potential became more negative in leaves of seedlings under severe stress. Water deficit increased fructose, glucose, sucrose and myo-inositol levels in leaves. Stems accumulated fructose, glucose and l-proline. Nitric oxide (NO) levels increased in the vascular cylinder of roots under severe stress while superoxide anion levels decreased due to augmented superoxide dismutase activity in this organ. Water deficit induced glutathione reductase activity in both roots and stems. Upon moderate or severe stress, catalase activity decreased in leaves and remained unaffected in the other seedling organs, allowing for an increase of hydrogen peroxide (H2O2) levels in leaves. Overall, the increase of signaling molecules in distinct organs-NO in roots, l-proline in stems and H2O2 and myo-inositol in leaves-contributed to the response of mahogany seedlings to water deficit by triggering biochemical processes that resulted in the attenuation of oxidative stress and the establishment of osmotic adjustment. Therefore, this body of evidence reveals that the development of newly germinated mahogany seedlings may occur in both natural habitats and crop fields even when water availability is greatly limited.

Biological activities of eco-friendly synthesized Hantzsch adducts.

Fourteen Hantzsch adducts with different substituents at the C-4 position were synthesized through multicomponent reactions by using citric or lactic acid as catalysts. To the best of our knowledge, this is the first report on the synthesis of such a class of compounds based on multicomponent reactions catalyzed by non-toxic organic acids. The potential to scavenge reactive nitrogen/oxygen species (RNS/ROS) and the ability to inhibit cancer cell growth were then investigated. Among the synthesized compounds, adduct 15 was the most promising free radical scavenger, while adduct 20 was shown to have a wider spectrum of action on the cancer cells studied. These results highlight Hantzsch adducts as lead compounds for obtaining new free radical scavengers and anticancer agents.

In vivo wound healing and antiulcer properties of white sweet potato (Ipomoea batatas).

The potential of tuber flour of Ipomoea batatas (L.) Lam. cv. Brazlândia Branca (white sweet potato) as wound healing and antiulcerogenic agent was investigated in vivo in animal model. Excision on the back of Wistar rats was performed to induce wounds that were topically treated with Beeler's base containing tuber flour of white sweet potato at 2.5%. Number of cells undergoing metaphase and the degree of tissue re-epithelialization were investigated 4, 7 and 10 days post-treatment. The protective effect of aqueous suspension of tuber flour (75 and 100 mg/kg animal weight) on gastric mucosa of Wistar rats was also studied by using the ethanol-induced ulceration model. Ointment based on white sweet potato at 2.5% effectively triggered the healing of cutaneous wound as attested by the increased number of cells undergoing metaphase and tissue re-epithelialization regardless the time of wound treatment. Tuber flour potentially prevented ethanol-induced gastric ulceration by suppressing edema formation and partly protecting gastric mucosa wrinkles. Crude extracts also exhibited potential as free radical scavengers. The results from animal model experiments indicate the potential of tuber flour of white sweet potato to heal wounds.