Uncarine E

Oxindole alkaloids from Uncaria tomentosa induce apoptosis in proliferating, G0/G1-arrested and bcl-2-expressing acute lymphoblastic leukaemia cells.[Pubmed: 16445836 ]

Br J Haematol. 2006 Mar;132(5):615-22.

Natural products are still an untapped source of promising lead compounds for the generation of antineoplastic drugs.
METHODS AND RESULTS:
Here, we investigated for the first time the antiproliferative and apoptotic effects of highly purified oxindole alkaloids, namely Isopteropodine (A1), pteropodine (A2), isomitraphylline (A3), uncarine F (A4) and mitraphylline (A5) obtained from Uncaria tomentosa, a South American Rubiaceae, on human lymphoblastic leukaemia T cells (CCRF-CEM-C7H2). Four of the five tested alkaloids inhibited proliferation of acute lymphoblastic leukaemia cells. Furthermore, the antiproliferative effect of the most potent alkaloids pteropodine (A2) and uncarine F (A4) correlated with induction of apoptosis. After 48 h, 100 micromol/l A2 or A4 increased apoptotic cells by 57%. CEM-C7H2 sublines with tetracycline-regulated expression of bcl-2, p16ink4A or constitutively expressing the cowpox virus protein crm-A were used for further studies of the apoptosis-inducing properties of these alkaloids. Neither overexpression of bcl-2 or crm-A nor cell-cycle arrest in G0/G1 phase by tetracycline-regulated expression of p16INK4A could prevent alkaloid-induced apoptosis.
CONCLUSIONS:
Our results show the strong apoptotic effects of pteropodine and uncarine F on acute leukaemic lymphoblasts and recommend the alkaloids for further studies in xenograft models.

Antimicrobial activity of isopteropodine.[Pubmed: 16042336 ]

Z Naturforsch C. 2005 May-Jun;60(5-6):385-8.

METHODS AND RESULTS:
Bioassay-directed fractionation for the determination of antimicrobial activity of Uncaria tomentosa, has led to the isolation of Isopteropodine (0.3%), a known Uncaria pentacyclic oxindol alkaloid that exhibited antibacterial activity against Gram positive bacteria.

Cat's Claw: an herb from the Peruvian Amazon.[Pubmed: 11363206]

Sidahora. 1995 Apr-May:35-6.

Uncaria tomentosa, also known as cat's claw, an herb from the highlands of the Peruvian Amazon, has been used by natives for hundreds of years to treat immunologic and digestive disorders. Research began in the 1970s to discover the benefits of this plant in relieving symptoms of cancers, arthritis, and other ailments.
METHODS AND RESULTS:
It has the ability to cleanse the digestive tract, aiding victims of Crohn's, colitis, gastritis and more. In a 1989 study by Klaus Keplinger, several alkaloid oxidants found in the plant's roots showed an ability to stimulate the immune system. The principal alkaloids are Isopteropodine and rynchophyiline.
CONCLUSIONS:
Extracts of cat's claw mixed with AZT in an experimental drug, called Krallendom, were effective in reducing symptoms in AIDS patients in Austria. The plant has been useful in reducing secondary effects of radiation and chemotherapy in cancer victims as well.

Biomed Chromatogr. 2017 Aug;31(8).

Rapid determination of oxindole alkaloids in cat's claw by HPLC using ionic liquid-based microwave-assisted extraction and silica monolithic column.[Pubmed: 28009448]

Cat's claw is a large woody vine with hook-like thorns, and has been traditionally used to treat inflammatory disorders in South and Central America.
METHODS AND RESULTS:
In this study, a rapid, validated high-performance liquid chromatographic (HPLC) method using a silica monolithic column was developed for the simultaneous determination of oxindole alkaloids, namely rhynchophylline, pteropodine, isomitraphylline and Isopteropodine, in cat's claw. The ionic liquid-based microwave-assisted extraction (ILMAE), considered as an environmentally friendly and powerful tool, was first applied in the extraction of oxindole alkaloids. To optimize the HPLC method, the stationary phases, pH values of mobile phase and flow rates were investigated. The validated HPLC method using a Monolithic RP18e column (100 × 4.6 mm) enables these analytes to be separated almost twice as fast as with a conventional particulate column (~16 vs ~30 min) with limits of quantification and detection of 0.5 and 0.15 μg/mL, respectively. The ILMAE conditions were optimized by the Taguchi orthogonal array design. In comparison with conventional water boiling extraction, ILMAE offers almost four times higher yields within an extremely short extraction time.
CONCLUSIONS:
The developed HPLC coupled with ILMAE method could be efficient and practical for rapid determination of oxindole alkaloids in cat's claw.