Undescribed glucosylceramide, flavonol triglycoside, and oleanane saponin from the halophyte Agathophora alopecuroides: Promising candidates for stimulating ceramide synthesis

The phytochemical study of Agathophora alopecuroides (Chenopodiaceae) led to the isolation of previously undescribed glucosylceramide, flavonol triglycoside, and triterpene oleanane saponin, together with eight known compounds. Their structures were elucidated using NMR analysis and HR-MS as (2′R, 12E) N-[(2S, 3S, 4R)-1-(β-D-glucopyranosyloxy)-3,4-dihydroxy-octadec-2-yl]-2-hydroxytetracos-12-enamide, namely Agathophamide A; isorhamnetin-3-O-[β-D-xylopyranosyl-(1→3)-α-L-rhamnopyranosyl-(1→6)]-β-D-galactopyranoside, namely Agathophoroside A; and 3-O-[4'-(β-D-xylopyranosyl)-β-D-glucuronopyranosyl]-28-O-β-D-glucopyranosyl-olean-12-en-3β-ol-28-oic acid, namely Solysaponin A. We evaluated the effect of extract and isolates on ceramide levels via the up-regulated expression of the enzyme for ceramide synthesis in HaCaT keratinocytes. Interestingly, the study results revealed that the methanol extract of A. alopecuroides, together with some isolated compounds significantly up-regulated the mRNA expression of ceramide synthase-3 by 1.2- to 4.3-fold compared with the control in HaCaT cells. These findings indicate that the halophyte A. alopecuroides is a promising source of candidate compounds that can contribute to ceramide synthesis via the up-regulated expression levels of ceramide synthase-3 in the ceramide synthesis pathway.