A homogeneous polysaccharide, ICMP-1, was isolated from the cultured mycelia of Isaria cicadae Miquel by hot water extraction. ICMP-1 (3.87 ×103 kDa) was a heteropolysaccharide mainly consisting of T-α-D-Glcp, →4)-α-D-Glcp-(1→, →4,6)-α-D-Manp-(1→, and →4)-β-D-Galp-(1→. In order to improve the antioxidant activity and the potential applications of ICMP-1, a typical ZnCl2 modification on ICMP-1 was carried out. Fourier-transform infrared spectroscopy (FT-IR), Energy dispersive spectrometer (EDS), scanning electron microscopy (SEM), atomic force microscope (AFM) and X-ray photoelectron spectroscopy (XPS) analysis confirmed that Zn was successfully introduced into the polymer chain of ICMP-1. The zinc modification derivative (ICMP-1-Zn) can alleviate H2O2-induced oxidative damage on PC12 cells. The stronger antioxidant activity of ICMP-1-Zn may be achieved by promoting the activity of zinc-containing enzymes, such as superoxide dismutase and lactate dehydrogenase.

polysaccharide, Structural characterization, Antioxidant activity, oxidative stress, Isaria cicadae Miquel, polysaccharide zinc complex

13C NMR data:
Linkage	Residue	C1	C2	C3	C4	C5	C6
4,4	aDGlcp	99.70	71.70	73.25	?	71.45	60.50
4,6,4	aDGlcp	100.78	74.52	73.29	74.77	73.54	60.65
4,6	bDGalp	104.27	73.99	72.60	76.37	73.30	62.71
4	aDManp	106.15	76.54	?	72.75	73.17	?
	aDGlcp


1H NMR data:
Linkage	Residue	H1	H2	H3	H4	H5	H6
4,4	aDGlcp	5.31	3.56	3.74	3.59	3.87	3.75
4,6,4	aDGlcp	5.08	4.14	4.10	3.82	3.85	3.69
4,6	bDGalp	4.57	3.18	3.71	3.67	3.85	3.62
4	aDManp	5.05	4.12	3.79	3.57	3.61	3.54
	aDGlcp


1H/13C HSQC data:
Linkage	Residue	C1/H1	C2/H2	C3/H3	C4/H4	C5/H5	C6/H6
4,4	aDGlcp	99.70/5.31	71.70/3.56	73.25/3.74	?/3.59	71.45/3.87	60.50/3.75
4,6,4	aDGlcp	100.78/5.08	74.52/4.14	73.29/4.10	74.77/3.82	73.54/3.85	60.65/3.69
4,6	bDGalp	104.27/4.57	73.99/3.18	72.60/3.71	76.37/3.67	73.30/3.85	62.71/3.62
4	aDManp	106.15/5.05	76.54/4.12	?/3.79	72.75/3.57	73.17/3.61	?/3.54
	aDGlcp

The spectrum also has 3 signals at unknown positions (not plotted).

There is only one chemically distinct structure:

SVGMWSMILES3D molIonize

 

Warning = sub-repeat ending at aDGlcp: large unit count (6) was reduced to 5
[*]O[C@@H]1[C@@H](CO)O[C@H](O[C@@H]2[C@@H](CO)O[C@H](O[C@@H]3[C@@H](CO)O[C@H](O[C@@H]4[C@@H](CO)O[C@H](O[C@@H]5[C@@H](CO)O[C@H](O[C@@H]6[C@@H](CO[C@@H]7O[C@H](CO)[C@H](O[C@H]8O[C@H](CO)[C@@H](O)[C@H](O)[C@H]8O)[C@H](O)[C@H]7O)O[C@H](O[C@@H]7[C@@H](CO)O[C@H]([*])[C@H](O)[C@H]7O)[C@@H](O)[C@H]6O)[C@H](O)[C@H]5O)[C@H](O)[C@H]4O)[C@H](O)[C@H]3O)[C@H](O)[C@H]2O)[C@H](O)[C@H]1O

1459.269 g/mol (C₅₄H₉₀R₂O₄₅, R = next and previous repeats, not counted in mol weight)