Inhibition of the gastric H+,K+-ATPase by plectrinone A, a diterpenoid isolated from Plectranthus barbatus Andrews

Inhibition of the gastric H+,K+-ATPase by plectrinone A, a diterpenoid isolated from Plectranthus barbatus Andrews

Author Schultz, Carla Google Scholar
Bossolani, Myllene P. Google Scholar
Torres, Luce M. B. Google Scholar
Lima-Landman, Maria Teresa R. Google Scholar
Lapa, Antonio J. Google Scholar
Souccar, Caden Google Scholar
Institution Universidade Federal de São Paulo (UNIFESP)
Bot Garden São Paulo
Abstract This work assessed the mechanism underlying the antisecretory gastric acid effect of Plectranthus barbatus Andrews (Lamiaceae) and active constituents. Popularly known as false-boldo, this plant is used in Brazilian folk medicine to treat gastrointestinal and hepatic ailments. the plant aqueous extract (AE) and isolated compounds were assayed in vivo in pylorus-ligated mice, and in vitro on acid secretion measured as [C-14] -arninopyrine ([C-14]-AP) accumulation in rabbit gastric glands and gastric H+,K+-ATPase preparations. Injected into the duodenal lumen, the AE of the plant leaves (0.5 and 1.0g/kg) decreased the volume (62 and 76%) and total acidity (23 and 50%) of gastric acid secretion in pylorus-ligated mice. Bioguided purification of the AE yielded an active fraction (IC50 = 24 kg/ml) that inhibited acid secretion in rabbit gastric glands with a potency 10 to 18 times greater than that of the originating extract, on both the basal and stimulated acid secretion by histamine (His) (1 mu M) or bethanechol (100 mu M). At the same concentrations the gastric H+,K+-ATPase activity was also inhibited. the active constituent was chemically identified as the abietanoid dienedione plectrinone A which reduced the H+,(+)-ATPase activity with IC50 = 171 mu M. the results indicate that inhibition of the gastric proton pump by this diterpenoid may account for the antisecretory acid effect and reputed antiulcer activity of Plectranthus barbatus. (c) 2006 Elsevier Ireland Ltd. All rights reserved.
Keywords Plectranthus barbatus
acid secretion
rabbit gastric glands
plectrinone A
Language English
Date 2007-04-20
Published in Journal of Ethnopharmacology. Clare: Elsevier B.V., v. 111, n. 1, p. 1-7, 2007.
ISSN 0378-8741 (Sherpa/Romeo, impact factor)
Publisher Elsevier B.V.
Extent 1-7
Access rights Closed access
Type Article
Web of Science ID WOS:000246059600001

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