Quillajasides A and B: New Phenylpropanoid Sucrose Esters from the Inner Bark of Quillaja saponaria Molina

Abstract

The phenolic composition of freshly prepared aqueous extracts of the inner bark of Quillaja saponaria Molina was compared to that of commercially available Quillaja extracts, which are currently used as emulsifiers in foods and cosmetics. Major phenolics in both extracts were (+)-piscidic acid and several p-coumaroyl sucrose esters. Among the latter, two new compounds were isolated and characterized: α-l-rhap-(1→4)-α-l-rhap-(1→3)-(4-O-(E)-p-coumaroyl)-α-d-glup-(1→2)-(3-O-(E)-p-coumaroyl)-β-d-fruf (quillajaside A) and β-d-apif-(1→4)-α-l-rhap-(1→4)-α-l-rhap-(1→3)-(4-O-(E)-p-coumaroyl)-α-d-glup-(1→2)-(3-O-(E)-p-coumaroyl)-β-d-fruf (quillajaside B). In addition, a putative biosynthetic pathway of at least 20 structurally related p-coumaroyl sucrose esters was tentatively identified. Besides their antioxidant activity and their potential function as substrate for enzymatic browning reactions, the new compounds are highly characteristic for both the inner bark of Q. saponaria and commercial extracts derived therefrom. Consequently, they might serve as authenticity markers for the detection of Quillaja extracts in food and cosmetic formulations.

Sugar Beet Extract (Beta vulgaris L.) as a New Natural Emulsifier: Emulsion Formation

“…For example, saponins as well as proteins comprise hydrophilic (e.g., sugar groups; serine) and hydrophobic regions (e.g., steroid or triterpene aglycone; alanine) within the same molecule, thus making them surface-active . In addition, other components such as polyphenols that are present in plant extracts can exhibit emulsifying properties that also play a significant role as antioxidants and in browning reactions and therefore contribute to product characteristics such as the color …”

“…5 In addition, other components such as polyphenols that are present in plant extracts can exhibit emulsifying properties that also play a significant role as antioxidants and in browning reactions and therefore contribute to product characteristics such as the color. 34 Sugar beet extract had a much lower saponin and polyphenol content but a higher protein content compared to Quillaja extract (Table 1). The saponin content in the sugar beet extract (>0.5%, w/w) is slightly higher than previously reported amounts found in roots (∼0.3%, w/w), 35 but reported protein contents are lower (∼0.8%, w/w), 36 which may be attributed to the accumulation of surface-active materials during the solvent extraction.…”

Montbresides A–D: antibacterial p-coumaroyl esters of a new sucrose-based tetrasaccharide from Crocosmia × crocosmiiflora (montbretia) flowers

“…Another highly unusual feature of montbresides is that the rhamnose residue is the D-rather than the common Lenantiomer. The latter is ubiquitous in plants as a component of pectic rhamnogalacturonans [11], and also occurs in a sucrose-based secondary metabolite, 3-O-(α-L-rhamnopyranosyl-(1→4)-α-L-rhamnopyranosyl)-4,3´-di-O-trans-p-coumaroylsucrose [12] . D-Rhamnose residues are well known in bacterial polysaccharides [13], but in plants they appear to be confined to a small number of secondary metabolites, albeit widely spread taxonomically.…”