Title
Hydrolyzable Tannins of Tamaricaceous Plants. V. Structures of Monomeric–Trimeric Tannins and Cytotoxicity of Macrocyclic-Type Tannins Isolated from Tamarix nilotica(1)
Author
Mohamed A. A. Orabi, Shoko Taniguchi, Hiroshi Sakagami, Morio Yoshimura, Takashi Yoshida, Tsutomu Hatano
Year
2013
Journal
Journal of Natural Products
Abstract
Three new ellagitannin monomers, nilotinins M5–M7 (1–3), a dimer, nilotinin D10 (4), and a trimer, nilotinin T1 (5), together with three known dimers, hirtellin D (7) and tamarixinins B (8) and C (9), and a trimer, hirtellin T2 (6), were isolated from Tamarix nilotica dried leaves. The structures of the tannins were elucidated by intensive spectroscopic methods and chemical conversions into known tannins. The new trimer (5) is a unique macrocyclic type whose monomeric units are linked together by an isodehydrodigalloyl and two dehydrodigalloyl moieties. Additionally, dimeric and trimeric macrocyclic-type tannins isolated from T. nilotica in this study were assessed for possible cytotoxic activity against four human tumor cell lines. Tumor-selective cytotoxicities of the tested compounds were higher than those of synthetic and natural potent cytotoxic compounds, including polyphenols, and comparable with those of 5-fluorouracil and melphalan.
Full Article
Instrument
J-720
Keywords
Circular dichroism, Cotton effect, Stereochemistry, Natural products, Medicinal, Pharmaceutical