The oxindole alkaloids are claimed to have immunostimulating properties in vitro, increasing phagocytotic activity and synthesis of WBCs (5) and enhancing T-helper cell function(2). Inhibition of TNF-alpha production (3) (4) has both been linked to observed anti-inflammatory activities. Mitraphylline isolated from cat’s claw was also identified as possessing anti-inflammatory effects by inhibiting the release of interleukins 1α, 1β, 4, 17, and TNF-α (21).
U. tomentosa water extracts have been shown to enhance DNA repair after chemical-induced damage (22). Protection against oxidative DNA damage following UVB exposure may occur via enhanced base excision repair and inherent antioxidant effects (23). The biphasic manner in which U. tomentosa modulates anxiety, initially inducing and then reversing these effects after long-term administration, is attributed to the presence of many alkaloids and flavonols (18).
Quinovic acid glycosides purified fraction of U. tomentosa inhibits the growth of human bladder cancer cell lines by inducing apoptosis through modulation of NF-κB (20). Cat’s claw also inhibits lactate dehydrogenase-A, an enzyme that is highly expressed in diverse human malignant and treatment-resistant tumors with clinically poor outcomes (24). In vivo studies demonstrate antineoplastic effects against breast tumors due to modulation of oxidative stress and synergy among constituents with antioxidant properties, rather than alkaloid activity (12).