Antioxidant and photoprotective activity of a crude extract of Culcitium reflexum H.B.K. leaves and their major flavonoids.

The aim of the present study was to evaluate the in vitro antioxidant and in vivo photoprotective activities of an ethanolic extract of Culcitium reflexum H.B.K. leaves (ECR extract). The antioxidant activity of the extract was assessed by means of three different in vitro tests: (1) bleaching of the stable 1,1-diphenyl-2-picrylhydrazyl radical; (2) peroxidation, induced by the water-soluble radical initiator 2,2'-azobis(2-amidinopropane)hydrochloride, on mixed dipalmitoylphosphatidylcholine/linoleic acid unilamellar vesicles; (3) UV radiation-induced peroxidation in phosphatidylcholine multilamellar vesicles. In all in vitro tests used the ECR extract showed a significant antioxidant effect. Furthermore, a gel formulation containing this extract proved, when topically applied, to afford a significant in vivo protection against UV-B-induced skin erythema in healthy human volunteers. Then, by chromatographic fractionation and spectroscopic methods, we identified some cinnamic acid derivatives and the major flavonoid constituents of the ECR extract, viz. the flavonols rutin, quercetin-3-O-beta-D-galactopyranoside-4'-O-beta-D-glucopyranoside, quercetin-3-O-beta-D-glucopyranoside, isorhamnetin-3-O-beta-D-galactopyranoside, quercetin and kaempferol.

1-ethyl and 1-propylazacycloalkan-2-one ester prodrugs of ketoprofen. Synthesis, chemical stability, enzymatic hydrolysis, anti-inflammatory activity, and gastrointestinal toxicity.

Six ketoprofen (CAS 22071-15-4) alkylazacycloalkan-2-one ester derivatives (I-VI) were synthesized and evaluated for their anti-inflammatory, analgesic, and ulcerogenic activities after oral administration. Furthermore these derivatives were assayed to determine in vitro their stability in pH 7.4 phosphate buffer and in simulated gastric fluid (pH 2.0 buffer) and their susceptibility to enzymatic cleavage in rat plasma. All the prodrugs showed a good stability both in pH 7.4 phosphate buffer and in pH 2.0 buffer, and they were readily hydrolyzed by rat plasma. Esters I-VI showed an anti-inflammatory activity, determined as the percent of inhibition of carrageenan-induced edema, similar to that of ketoprofen, although at higher doses. They were significantly less irritating to the gastric mucosa than the parent drug. In the mouse acetic acid induced writhing assay, the prodrugs exhibited, following acute administration, a good analgesic activity.