Caffeic acid and some of its derivatives such as caffeic acid phenetyl ester (CAPE) and octyl caffeate are potent antioxidants which present important anti-inflammatory actions. The present study assessed the in vitro and in vivo effects of five caffeic acid derivatives (caffeic acid methyl, ethyl, butyl, octyl and benzyl esters) and compared their actions to those of CAPE. In the model of LPS-induced nitric oxide (NO) production in RAW 264.7 macrophages, the pre-incubation of all derivatives inhibited nitrite accumulation on the supernatant of stimulated cells, with mean IC50 (microM) values of 21.0, 12.0, 8.4, 2.4, 10.7 and 4.80 for methyl, ethyl, butyl, octyl, benzyl and CAPE, respectively. The effects of caffeic acid derivatives seem to be related to the scavenging of NO, as the compounds prevented SNAP-derived nitrite accumulation and decreased iNOS expression. In addition, butyl, octyl and CAPE derivatives significantly inhibited LPS-induced iNOS expression in RAW 264.7 macrophages. Extending the in vitro results, we showed that the pre-treatment of mice with butyl, octyl and CAPE derivatives inhibited carrageenan-induced paw edema and prevented the increase in IL-1beta levels in the mouse paw by 30, 24 and 36%, respectively. Butyl, octyl and CAPE derivatives also prevented carrageenan-induced neutrophil influx in the mouse paw by 28, 49 and 31%, respectively. Present results confirm and extend literature data, showing that caffeic acid derivatives exert in vitro and in vivo anti-inflammatory actions, being their actions mediated, at least in part by the scavenging of NO and their ability to modulate iNOS expression and probably that of other inflammatory mediators.

The aim of this study was to evaluate the analgesic effect of the methanolic extract from callus culture of Phyllanthus tenellus, P. corcovadensis and P. niruri in several models of pain in mice. The extracts (medium containing 2,4-dichlorophenoxyacetic acid) of P. corcovadensis, P. niruri and P. tenellus (3-90 mg kg-1, i.p.) caused graded inhibition of abdominal constrictions induced by acetic acid (0.6%), with ID50 (i.e. dose that reduced response of control by 50%) values of about 30, 19 and > 30 mg kg-1, respectively. The extract of callus of Phyllanthus obtained in indole-3-butyric acid and indole-3-acetic acid media (3-90 mg kg-1, i.p.) caused a similar analgesic effect. In the formalin test, the extract of P. tenellus obtained in indole butyric acid medium (3-100 mg kg-1, i.p.) inhibited only the second phase of formalin-induced pain with an ID50 value of about 100 mg kg-1. Both the indole acetic acid and indole butyric acid methanolic extracts of P. tenellus and P. corcovadensis (10-100 mg kg-1, i.p.) dose-dependently inhibited both phases of formalin-induced pain (ID50 values for the second phase were approx. 100 and 52 mg kg-1, respectively). However, the extract of callus from Phyllanthus failed to affect formalin-induced paw oedema, as well as the response to radiant heat in the tail-flick test. In addition, the analgesic effect of morphine, but not the analgesic effects caused by Phyllanthus callus extract, was fully antagonized by naloxone.(ABSTRACT TRUNCATED AT 250 WORDS)

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Plants belonging to the genus Maytenus (Celastraceae) are routinely used in folk medicine in Brazil and other countries to treat a variety of illnesses, the most common of which are gastric disorders. Several studies have reported on the importance of these biological effects, and the chemical substances, mostly terpenoids and flavonoid glycosides, responsible for them. This review summarizes the ethnopharmacological, chemical and pharmacological knowledge of plants of the Maytenus genus, with particular emphasis on those growing in Brazil.

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