Triterpenoids with acetylcholinesterase inhibtion from Chuquiraga erinacea D. Don. subsp. erinacea

VELA GUROVIC, MARÍA SOLEDAD; CASTRO, MARÍA JULIA; RICHMOND, VICTORIA; FARAONI, MARÍA B.; MAIER, MARTA SILVIA; ANA PAULA MURRAY

PLANTA MEDICA

George Thieme Verlag

Lugar: Suttgart; Año: 2010 vol. 76 p. 607 - 610

0032-0943

A bioactivity guided approach was taken to identify the acetylcholinesterase (AChE) inhibitory agents in the ethanolic extract of Chuquiraga erinacea D. Don. subsp. erinacea leaves using a bioautographic method. This permitted the isolation of the pentacyclic triterpenes calenduladiol (1), faradiol (2), heliantriol B2 (3), lupeol (4) and a mixture of alpha-and beta-amyrin (5a and 5b) as active constituents. Pseudotaraxasterol (6) and taraxasterol (7) were also isolated from this extract and showed no activity at the same analytical conditions. Compound 1 showed the highest AChE inhibitory activity with a 31.2 % of inhibition at 0.5 mM. Looking forward to improve the water solubility of the active compounds, the sodium sulfate ester of 1 was prepared by reaction with (CH3)3N.SO3 complex. The semisynthetic derivative disodium calenduladiol disulfate (8) elicited higher AChE inhibition than 1 with 94.1 % of inhibition at 0.5 mM (IC50 = 0,190 ± 0,003 mM). Compounds 1, 2, 3, 5, 6 and 7 are reported here for the first time in C. erinacea. This is the first report of AChE inhibition from calenduladiol (1) as well as from a sulfate derived from a natural product.