Fraction and chemical analysis of antioxidant active polysaccharide isolated from flue-cured tobacco leaves.
BACKGROUND
The metabolic compounds from tobacco were investigated to posses various biological activities, such as antioxidant, antimicrobial and neuroprotective activities.


METHODS
Polysaccharides were isolated from the ultrasound-assisted extraction of flue-cured tobacco with hot water. The purified polysaccharides were analyzed by GC-MS, FT-IR, and TGA (Thermogravimetric analysis). The antioxidant activities of purified polysaccharides were evaluated in vitro.


RESULTS
Two polysaccharides (Fr-I and Fr-II) were isolated and purified. The analysis of monosaccharide composition in the polysaccharide by GC/MS revealed that Fr-I and Fr-II were heteropolysaccharides. Fr-I consisted of D-mannose and galactose, ribose and arabinose, while Fr-II was mainly composed of glucose, allose, galactose and mannose. Thermo gravimetric analysis (TGA) indicated that the degradation temperature (Td) of the Fr-I (241 °C) was higher than that of Fr-II (220 °C). Both samples showed inhibitory effects on OH (hydroxyl) and DPPH (2, 2-diphenyl-1-picryl-hydrazyl-hydrate) radical in a concentration-dependent manner. Comparing Fr-I with Fr-II, the latter has a strong scavenging ability.


CONCLUSIONS
Both polysaccharide fractions showed significant antioxidant effects. Various factors influenced the antioxidant activity of polysaccharides.
Department of Tobacco Engineering, College of Food and Biological Engineering, Zhengzhou University of Light Industry, Zhengzhou, Henan, P.R. China.
Chunping
C
Xu
Department of Tobacco Engineering, College of Food and Biological Engineering, Zhengzhou University of Light Industry, Zhengzhou, Henan, P.R. China.
Chenchen
C
Yang
Department of Tobacco Engineering, College of Food and Biological Engineering, Zhengzhou University of Light Industry, Zhengzhou, Henan, P.R. China.
Duobin
D
Mao
Antioxidant activity; flue-cured tobacco leaves; fraction; polysaccharide