Biochemical Systematics and Ecology 96 (2021) 104262
8
agreement with the presence of ions corresponding to luzonicoside.
The collision-induced dissociation (CID) mass spectrum of the m/z
921.4458 and 891.4353 ions allows us to identify the key signals of two
types of glycosidic chains. The m/z 541.1379, m/z 523.1274 [541-18]
and m/z 374.0951 peaks would correspond to the signature of the
GlcA-Gal-Glc ([GlcA-Gal-Glc + Na]
+
) oligosaccharide chain, and the m/
z 511.1276, m/z 493.1168 [511-18] and m/z 317.0847 peaks as a
signature of the GlcA-Ara-Glc ([GlcA-Ara-Glc + Na]
+
) oligosaccharide
chain.
The fragmentation sequence exemplified in Fig. 4, Fig. S2 and Fig. S3
established the molecular formula C 27 H 40 O of the aglycone part for m/z
921 and 891, which confirm that the fragment ions originate from
sodium-cationized sepositoside and luzonicoside.
The collision-induced dissociation (CID) mass spectrum of the m/z
907.4306 ions detected in the oral body wall is presented in
supplementary data Fig. S4 and Fig. 5. It shows the co-occurrence of
three fragmentation patterns (Fig. 5): two fragmentation routes represented by black lines (solid and dotted lines (A)) can be associated to
sepositoside B of E. sepositus (structure 1 in Fig. 6), whereas the third
fragmentation pathways, identified by the gray lines (dotted lines (B)),
are characteristic of luzonicoside F ions (structure 7 in Fig. 6).
As far as the solid black line, the mass differences between the
fragment ions are attributable to the losses of glucuronic acid, galactose
and aglycone moiety ultimately leading to the m/z 185.0423 ions. When
following the dotted black line in the scheme, i.e. m/z 907.4306 ⇢ m/z
541.1381 ⇢ m/z 523.1275 ⇢ m/z 347.0953 ⇢ m/z 185.0423, it is
interesting to note that the ultimate mass transition corresponds to m/z
523.1275 and m/z 347.0953. This can unambiguously reveal the presence of GlcA-Gla-Glc oligosaccharide chain and confirm that the fragment ions are associated to sepositoside B of E. Sepositus. The complete
Fig. 5. Collision-induced dissociation experiments of the m/z 907 ions obtained upon ESI MS/MS analysis of the oral body wall saponin extract of females Individual:
fragmentation reactions of (A) sepositoside B of E. sepositus; and (B) lozonicoside F of E. luzonicus.
B. Dahmoune et al.
8
agreement with the presence of ions corresponding to luzonicoside.
The collision-induced dissociation (CID) mass spectrum of the m/z
921.4458 and 891.4353 ions allows us to identify the key signals of two
types of glycosidic chains. The m/z 541.1379, m/z 523.1274 [541-18]
and m/z 374.0951 peaks would correspond to the signature of the
GlcA-Gal-Glc ([GlcA-Gal-Glc + Na]
+
) oligosaccharide chain, and the m/
z 511.1276, m/z 493.1168 [511-18] and m/z 317.0847 peaks as a
signature of the GlcA-Ara-Glc ([GlcA-Ara-Glc + Na]
+
) oligosaccharide
chain.
The fragmentation sequence exemplified in Fig. 4, Fig. S2 and Fig. S3
established the molecular formula C 27 H 40 O of the aglycone part for m/z
921 and 891, which confirm that the fragment ions originate from
sodium-cationized sepositoside and luzonicoside.
The collision-induced dissociation (CID) mass spectrum of the m/z
907.4306 ions detected in the oral body wall is presented in
supplementary data Fig. S4 and Fig. 5. It shows the co-occurrence of
three fragmentation patterns (Fig. 5): two fragmentation routes represented by black lines (solid and dotted lines (A)) can be associated to
sepositoside B of E. sepositus (structure 1 in Fig. 6), whereas the third
fragmentation pathways, identified by the gray lines (dotted lines (B)),
are characteristic of luzonicoside F ions (structure 7 in Fig. 6).
As far as the solid black line, the mass differences between the
fragment ions are attributable to the losses of glucuronic acid, galactose
and aglycone moiety ultimately leading to the m/z 185.0423 ions. When
following the dotted black line in the scheme, i.e. m/z 907.4306 ⇢ m/z
541.1381 ⇢ m/z 523.1275 ⇢ m/z 347.0953 ⇢ m/z 185.0423, it is
interesting to note that the ultimate mass transition corresponds to m/z
523.1275 and m/z 347.0953. This can unambiguously reveal the presence of GlcA-Gla-Glc oligosaccharide chain and confirm that the fragment ions are associated to sepositoside B of E. Sepositus. The complete
Fig. 5. Collision-induced dissociation experiments of the m/z 907 ions obtained upon ESI MS/MS analysis of the oral body wall saponin extract of females Individual:
fragmentation reactions of (A) sepositoside B of E. sepositus; and (B) lozonicoside F of E. luzonicus.
B. Dahmoune et al.