ACETYLCHOLINESTERASE INHIBITION AND PHYTOCHEMISTRY OF Acalypha communis Müll. Arg. (EUPHORBIACEAE)

RODRIGUEZ, BJ; VALLEJO, MG

Congreso; 1 XLI REUNIÓN CIENTÍFICA ANUAL DE LA SOCIEDAD DE BIOLOGÍA DE CUYO ?Una Salud: salud humana, salud animal y salud ambiental?; 2023

In Alzheimer's disease, where there is a decrease in acetylcholine levels in the Central Nervous System affecting memory and learning,acetylcholinesterase (AChE) inhibitor drugs treatments are mainly used. In order to search new inhibitors, we studied A. communis, havingpreviously demonstrated the effect of its hydroalcoholic extract (ACHA) on AChE. For this species, it was previously detected quercetin(Q), rutin (R) and gallic acid (GA) in a 95% ethanolic extract. The aim of this work was to evaluated different ACHA fractions activity. Theywere obtained by partition of ACHA (dry, redissolved in water) with CH2Cl2 and subsequent separation by column chromatography (CC),with silica gel as the stationary phase and a gradient of increasing polarity solvents as the mobile phase: 100% Hexane→ 100%CHCl3→100% AcOEt→100% EtOH. 13 fractions were obtained: from G1 to G13. Then, the inhibition on AChE of each fraction wasevaluated, according to the Ellman method, at a 250μg/mL concentration. Chemical content of these fractions was analyzed in turn by HPLC-MS. Regarding AChE inhibition, G6 exhibited the highest activity: 72.13%, while G1 exerted the lowest: 5.83%. Remaining fractionsinhibition were G3: 38.72%; G7: 42.13%; G8:35.42%; G10: 46.38% and G11: 35.42%. HPLC-MS analysis results indicate that Q is presentin G1 in low concentration; in G3, an unknown compound of M+= 596.19 was observed. In G6, Q, R and AG were no detected, and in G7,G8, G10 and G11, same M+ to that of R compound was detected, but having different fragmentation pattern, which would indicate that itcould be another metabolite. AG was not detected in any of the fractions. Relating the phytochemical composition to the observed inhibitoryeffect, it can be concluded that this is not due to AG or Q, since they are not present in the samples that showed greater inhibition, and inthose that gave moderate inhibition a compound of the same M+ as R was detected. Further, the G3 component and those present in theremaining fractions will be analyzed to predict, through the study of this species metabolomics, using multivariate analysis tools, whichcompound is responsible for the inhibitory activity in the most active samples.