Structural elucidation of the polysaccharide from Sterculia apetala gum by a combination of chemical methods and NMR spectroscopy

Structure characterization of a novel neutral polysaccharide isolated from Ganoderma lucidum fruiting bodies

“…Based on the methylation analysis in Section 3.2 and the cross peak of d 16.9/1.24 observed in HSQC spectrum which corresponded to methyl group (Marvelys, Maritza, Lilian, Gladys, & Julio, 2006), it was concluded that residue D was a b-L-rhamnose residue. The downfield shifts of d 103.8 (C-1) and d 75.15 (C-2) from the chemical shifts of standard rhamnopyranose indicated that residue D was a 1,2-linked b-L-rhamnopyranose.…”

Structural features and immunostimulating effects of three acidic polysaccharides isolated from Panax quinquefolius

“…So in the polysaccharides spectra of PPQA2 and PPQA5, the signal at 52.9 ppm was assigned to methyl groups binding to carboxyl groups; the signal approximately at 100 ppm were due to the anomeric carbon of methyl galacturonate and glucuronate acids; the signal at 170.8 ppm attributed to carboxyl groups bound by methyl groups; while the signal at 174.8 ppm was derived from ionic carboxyl groups (C-6) of uronic acids [23,24]. The signal for C-5 of methyl uronic acid residues appeared approximately at 70.6 ppm [11,25]. Furthermore, the signals at ı 20.1 ppm suggested PPQA2 and PPQA5 contained O-acetyl groups [26].…”

Structural characterization and bioactivity evaluation of an acidic proteoglycan extract from Ganoderma lucidum fruiting bodies for PTP1B inhibition and anti‐diabetes

“…Similarly, along with 1 H‐ 1 H TOCSY spectrum (Figure b), the resonances at δ H 3.76, 3.54, and 3.93 ppm were assigned to H‐4, H‐5, and H‐6 of residue A . Meantime, the large coupling constants 3 J H‐2,H‐3 and 3 J H‐3,H‐4 values of residue A supported its being D‐glucosyl moiety . Based on the 1 H NMR assignment, complete carbon signals in residue A were easily assigned from the HSQC (Figure b) spectrum as C‐1 of δ C 102.20, C‐2 of δ C 72.84, C‐3 of δ C 73.85, C‐4 of δ C 68.92, C‐5 of δ C 80.59, and C‐6 of δ C 69.45 ppm.…”