Anti-inflammatory and antioxidant activities of cat’s claw (Uncaria tomentosa and Uncaria guianensis) are independent of their alkaloid content

Cat’s claw is an herbal medicine from the Amazon that is used widely to treat inflammatory disorders. The purpose of this study was to characterize the antioxidative and anti inflammatory properties of cat’s claw, Uncaria tomentosa (UT) and Uncaria guianensis (UG). Alkaloids and flavanols were determined using reversed-phase HPLC; scavenging of 1,1-diphenyl-2-picrilhydrazyl (DPPH), hydroxyl radicals, and lipid peroxidation by spectrophotometry; and TNFα production by ELISA. Anti-inflammatory activity was assessed in vitro by inhibition of TNFα and nitrite production from RAW 264.7 cells exposed to LPS (50 ng/ml) and in vivo using the indomethacin-induced gastritis model. Apoptosis was assessed using the TUNEL technique and TNFα mRNA by in situ RT-PCR. In each of the antioxidant assays tested, UG was more potent than UT (P < 0.01). Thetotal oxindole and pentacyclic alkaloid content of UT was 35-fold > UG. The IC50 value for inhibition of TNFα production was significantly (P < 0.01) higher for UT (14.1 ng/ml) vs UG (9.5 ng/ml),yet at concentrations that were considerable lower than that required for antioxidant activity.Non-alkaloid HPLC fractions from UT decreased LPS-induced TNFα and nitrite production in RAW 264.7 cells (P < 0.01) at a concentration range comparable to the parent botanical. Oral pretreatment for 3 d with UT protected against indomethacin-induced gastritis, and prevented TNFαmRNA expression and apoptosis. These results indicate that while both species of cat’s claw provide effective antioxidant and anti-inflammatory activities, U. guianensis is more potent. In conclusion, the presence of oxindole or pentacyclic alkaloids did not influence the antioxidant and anti inflammatory properties of cat’s claw