Here are some links about the items you posted about, amit.

Astragalus:
http://www.umm.edu/altmed/articles/a...lus-000223.htm
(possible interaction with immune suppressing drugs/steroids)

Shiitake:
https://healthlibrary.epnet.com/GetC...hunkiid=220562
(weak evidence)

Kombucha:
http://en.wikipedia.org/wiki/Kombucha
questionable

Echinacea:
http://www.umm.edu/altmed/articles/echinacea-000239.htm
There are far more warnings and studies for this herb, to be used very carefully, and perhaps not at all for those with autoimmune disorders.

I have found it best to confirm things that one may see in the general media. Often the journalists are not that prepared or accurate about medical things, or especially about herbal or supplement information. (this is because the information may change rapidly).

The University of Maryland site, and the Natural Pharmacy site are just about the best I have found. Linus Pauling Institute is excellent for vitamins/minerals, but they don't do herbs as a rule.

Also beware of sites that sell their own proprietary products (not like iherb which sells everything). Information from specialty sites can be misleading, in order to hype up their product.