The major constituents in picrorhiza are the glycosides picroside I, kutkoside, androsin, and apocynin. They have been shown in animal studies to be antiallergic, to inhibit platelet-activating factor (an important pro-inflammatory molecule),12 and to decrease joint inflammation.13 According to test tube and animal studies, picrorhiza has antioxidant actions, particularly in the liver.14, 15 Picroliv (a commercial mixture containing picroside I and kutkoside) has been shown to have an immunostimulating effect in hamsters, helping to prevent infections.16 Picrorhiza increases bile production in the liver, according to rat studies.17 It has also been shown to protect animals from damage by several potent liver toxins, offering protection as good as or better than silymarin (the flavonoids found in milk thistle).18, 19 However, it does not have the amount of human research as silymarin. Picrorhiza has also shown to reduce formation of liver cancer due to chemical exposures in animal studies.20
Human studies on this plant are not prolific. A series of cases of acute viral hepatitis in India were reportedly treated successfully by a combination of picrorhiza with a variety of minerals.21 A number of similar reports have appeared in Indian literature over the years. No double-blind clinical trials have yet been published, however.
Two preliminary trials suggest that picrorhiza may improve breathing in asthma patients and reduce the severity of asthma.22, 23 Although, a follow-up double-blind trial did not confirm these earlier trials.24
A preliminary trial conducted in India found a small benefit for people with arthritis (primarily rheumatoid arthritis).25
Picrorhiza in combination with the drug methoxsalen was found in a preliminary trial to hasten recovery in people with vitiligo faster than those receiving methoxsalen and sun exposure alone.26