Impacts of sulfur fumigation on the chemistry and immunomodulatory activity of polysaccharides in ginseng.

Ginseng is widely regarded as a panacea in Oriental medicine mainly due to its immunomodulatory activity. We previously found that sulfur fumigation, a commonly used pesticidal and anti-bacterial processing practice, weakened the immunomodulatory activity of ginseng. However, if and how sulfur fumigation affects the polysaccharides in ginseng, the crucial components contributing to the immunomodulatory function, remain unknown. Here we report that polysaccharides extracted from sulfur-fumigated ginseng (SGP) presented different chemical properties with polysaccharides extracted with non-fumigated ginseng (NGP), particularly increased water extraction yield and decreased branching degree. SGP had weaker immunomodulatory activity than NGP in immunocompromised mice, as evidenced by less improved immunophenotypes involving body weight, immune organ indexes, white blood cells, lymphocyte cell populations and inflammation. The different immunomodulatory activities were accompanied by changes in the interaction between the polysaccharides and gut microbiota, in which SGP stimulated the growth of different bacteria but produced less SCFAs as compared to NGP. Fecal microbiota transplantation experiment suggested that gut microbiota played a central role in causing the weakened immunomodulatory activity in vivo. This study provides definite evidence that sulfur fumigation affects the chemistry and bioactivity of ginseng polysaccharides, thereby contributing to understanding how sulfur fumigation weakens the immunomodulatory activity of ginseng.

[Inhibitory effects of dry Acorus calamus extracts on the growth of two water bloom-forming algal species].

A trial with different concentrations of aqueous extracts from dry Acorus calamus plants was conducted to study the effects of the extracts on Microcystis aeruginosa and Chlorella pyrenoidosa growth. Allelopathic effects were observed. High concentration ( >40 ml x L(-1)) extracts inhibited the growth of the two algal species at low inoculation cell density significantly (P < 0.01), with the maximal inhibition rate being 98.66% for M. aeruginosa and 92.38% for C. pyrenoidosa, while low concentration ( < 30 ml x L(-1)) extracts promoted the growth of C. pyrenoidosa. Neither high nor low concentration extracts had significant effects on the growth of the two algal species at high inoculation cell density (P > 0.05). The comparison of adding the aqueous extracts once and semiconsecutively showed that the allelochemicals in the extracts were easy to be degraded, suggesting that the continuous secretion of allelochemicals in natural water bodies could play an important role in inhibiting algal growth.