Polyphenolic compounds and flavonoids found in Triphala are thought to be responsible for many of its effects. Gallic acid, a major polyphenol, has antioxidant and immunomodulatory properties ^(11) (33).

In preclinical studies, Terminalia chebula inhibited hyaluronidase and collagenase to prevent cartilage degradation ⁽⁷⁾. Antiarthritic and anti-inflammatory effects of Triphala are attributed to NF-kBp65 and COX-2 inhibition ^(25) (26), whereas the anticolitic effects are attributed to antioxidant properties ⁽²²⁾. Nephrotoxic effects were also thought to be attenuated via increased antioxidant activity ⁽²³⁾.

Triphala appears to stimulate neutrophil function and decrease corticosterone levels in immunized rats exposed to noise stress ⁽³⁴⁾. It also exerted radioprotective effects ⁽²¹⁾ by inhibiting oxidative damage. Triphala increased ROS in breast cancer cells resulting in apoptosis ⁽⁸⁾, protected against X-radiation and bleomycin, both of which generate DNA strand breaks in HeLa cells ⁽⁴²⁾, and appeared to protect mice from radiation-induced mortality ^(2) (3).

Despite its antibacterial properties, compounds in Triphala may promote the formation of oral bacterial biofilm via activation of glucosyl transferases ⁽³⁰⁾.

In a small study of healthy human volunteers, Triphala increased cytotoxic T cells and NK cells ⁽³¹⁾.