Now Astragalus – Immune System Support! Adaptogenic Herb!. Active Ingredients Include Flavonoids, Free Amino Acids And More!Natural Health. Active Ingredients Include Flavonoids, Free Amino Acids And More!Astragalus Root (Huang qi) has been used as a popular herbal tonic in China for many centuries. Some of the known active components include flavonoids, free amino acids, trace minerals and polyphenols. Astragalus is believed to build stamina and vitality. It has a reputation for improving overall health by helping the body to maintain a healthy immune system. As an antioxidant, it helps to counteract cell damage caused by unstable oxygen molecules called free radicals.