Vitellaroside, A New Cerebroside from Vitellaria paradoxa (Sapotaceae) and its Bioactivities

Abstract

A new cerebroside (2R)-2-hydroxy-N-[(Z,2S,3S,4R)-1-O-β-D-glucopyranosyl-3,4-dihydroxynonadec-8-en-2-yl] nonacosanamide (1) was isolated from the wood of roots of V. paradoxa along with six known compounds including catechin (2), quercetin (3), spinasterol 3-O-β-D-glucopyranoside (6), gallic acid (7) and a mixture of β-sitosterol (4) and stigmasterol (5). The structure of the new compound was established by 1D (1 H and 13 C NMR) and 2D NMR (COSY and HSQC) spectroscopy, extensive mass spectrometry and by comparison with published data. The antibacterial, α-glucosidase and alkaline phosphatase (AP) inhibitory activities of all the pure compounds were evaluated. The antibacterial activities were evaluated against three gram negative bacteria (Escherichia coli; Salmonella typhimurium and Pseudomonas aeruginosa) while APs inhibitory activities were evaluated on h-TNAP and h-IAP. Significant antibacterial activity was recorded for quercetin (3) against P. aeruginosa. Most of the compounds except 1 and 6 were found to be inhibitors of α-glucosidase. The highest inhibitory potential being recorded for quercetin (3) with IC 50 value of 4.30 ± 0.01 µM, 55 fold higher than the standard drug acarbose (IC 50 =234.6 ± 2.01 µM). All tested compounds exhibited moderate inhibitory activities against APs. h-TNAP inhibitory values were ranged between 41.24 ± 1.33 µM and 312.54 ± 6.44 µM while h-IAP inhibitory values were in the range of 47.95 ± 0.35 µM and 777.47 ± 18.55 µM. Quercetin (3) was found to be the most active h-IAP inhibitor (IC 50 =47.95 ± 0.35 mM), whereas, spinasterol 3-O-β-D-glucopyranoside (6) was found to be the most active h-TNAP inhibitor (IC 50 =41.24 ± 1.33 mM). The new compound (1) showed moderate inhibition on h-IAP (78.11 ± 3.70 µM) and on h-TNAP (88.84 ± 2.70 µM).