Extracts from the leaves of Campomanesia velutina inhibits production of LPS/INF-γ induced inflammatory mediators in J774A.1 cells and exerts anti-inflammatory and antinociceptive effects in vivo

Campomanesia velutina (Cambess) O. Berg, Myrtaceae, popularly known as "gabiroba" or "guavira", is used in traditional Brazilian medicine to treat several diseases, including inflammation and rheumatism. Extraction and isolation from leaves of the plant afforded the active compound myricetin 3-O-rhamnoside, also known as myricitrin. The ethanolic extract of leaves of C. velutina and its ethyl acetate and methanolic fractions were evaluated in inflammation (carrageenan-induced paw oedema) and analgesic models (acetic acid-induced abdominal writhing and hot plate test). Moreover, the ethanolic extract, its fractions and the isolated compound were also in vitro evaluated for their ability to modulate NO, TNF-α and IL-10 production from J774A.1 macrophages stimulated by LPS/IFN-γ. In vivo assays showed remarkable anti-inflammatory activity of ethanolic extract, ethyl acetate and methanolic fractions. The antinociceptive activity of ethanolic extract and A was demonstrated in acetic acid-induced abdominal writhing test. In vitro assays demonstrated that ethyl acetate and methanolic fractions fraction and myricitrin inhibited NO production from macrophages J774A.1. Also Myricitrin induced production of IL-10 anti-inflammatory cytokine. None of the samples was able to inhibited TNF-α production. The results demonstrated for the first time the anti-inflammatory and antinociceptive activity of C. velutina. .

Kinetic characterization and inhibition of the rat MAB elastase-2, an angiotensin I-converting serine protease.

An elastase-2 has been recently described as the major angiotensin (Ang) II-forming enzyme of the rat mesenteric arterial bed (MAB) perfusate. Here, we have investigated the interaction of affinity-purified rat MAB elastase-2 with some substrates and inhibitors of both pancreatic elastases-2 and Ang II-forming chymases. The Ang II precursor [Pro 11 -D-Ala 12]-Ang I was converted into Ang II by the rat MAB elastase-2 with catalytic efficiency of 8.6 min-1 microM-1, and the chromogenic substrates N-succinyl-Ala-Ala-Pro-Leu-p-nitroanilide and N-succinyl-Ala-Ala-Pro-Phe-p-nitroanilide were hydrolyzed by the enzyme with catalytic efficiencies of 10.6 min-1 microM-1 and 7.6 min-1 microM-1, respectively. The non-cleavable peptide inhibitor CH-5450 inhibited the rat MAB elastase-2 activities toward the substrates Ang I (IC50 = 49 microM) and N-succinly-Ala-Ala-Pro-Phe-p-nitroanilide (IC 50 = 4.8 microM), whereas N-acetyl-Ala-Ala-Pro-Leu-chloromethylketone, an effective active site-directed inhibitor of pancreatic elastase-2, efficiently blocked the Ang II-generating activity of the rat MAB enzyme (IC 50 = 4.5 microM). Altogether, the data presented here confirm and extend the enzymological similarities between pancreatic elastase-2 and its rat MAB counterpart. Moreover, the thus far unrealized interaction of elastase-2 with [Pro 11-D-Ala 12]-Ang I and CH-5450, both regarded as selective for chymases, suggests that evidence for the in vivo formation of Ang II by chymases may have been overestimated in previous investigations of Ang II-forming pathways.