Dimeric ellagitannins from Alnus japonica

Lee, Min-Won; Tanaka, Takashi; Nonaka, Gen‐ichiro; Nishioka, Itsuo

doi:10.1016/0031-9422(92)83642-c

Cited by 63 publications

(31 citation statements)

References 12 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…3) Previous studies on the chemical constituents of A. hirsuta have led to the isolation of various natural products such as tannins, 4,5) flavonoids, 6,7) diarylheptanoids, [8][9][10] and triterpenoids.…”

mentioning

confidence: 99%

Diarylheptanoids from Alnus hirsuta Inhibit the NF-kB Activation and NO and TNF-.ALPHA. Production

Jin

Cai

et al. 2007

Biological & Pharmaceutical Bulletin

View full text Add to dashboard Cite

Nuclear factor-kB (NF-kB) is a dimeric transcription factor that activates the expression of many genes involved in the inflammatory process, e.g., the cytokines IL-1b, IL-2, and TNF-a, adhesion molecules, and enzymes such as iNOS, cyclooxygenase-II, and 5-lipoxygenase.1) NF-kB is inactive without stimulation, and it is activated by extracellular signals such as TNF-a, IL-1, lipopolysaccharide (LPS), UV light, and phorbol esters. In unstimulated cells, NF-kB is retained in the cytoplasm via interaction with its inhibitor IkB. In response to various proinflammatory stimuli, IkB is phosphorylated by IkB kinase complex. This leads to the ubiquitination and subsequent proteasome-mediated degradation of IkB, allowing NF-kB to enter the nucleus. NF-kB is highly activated at the site of inflammation of diverse diseases such as rheumatoid arthritis, atherosclerosis, asthma, inflammatory bowel disease, and Helicobacter pylori-associated gastritis 1) and associated with cancer, cachexia, diabetes, euthyroid sick syndrome, and AIDS.2) With its apparent involvement in a variety of human diseases, NF-kB has been shown to be the target of several anti-inflammatory and anticancer drugs. 2)In our search for inhibitors of NF-kB activity from natural products, the MeOH extract of the stem bark of Alnus hirsuta showed significant inhibitory activity of NF-kB activation (IC 50 value, 16.5 mg/ml). The species A. hirsuta belongs to the Betulaceae, and geographically distributes in Korea, Japan, Northeast China, and Russia. It is a broad-leaved deciduous tree that grows in damp places. The bark of this species has been used in Chinese and Korean traditional medicine as a remedy for fever, hemorrhage, diarrhea, and alcoholism.3) Previous studies on the chemical constituents of A. hirsuta have led to the isolation of various natural products such as tannins, 4,5) flavonoids, 6,7) diarylheptanoids, [8][9][10] and triterpenoids.11) It has also been reported to exhibit a variety of bioactivities such as antioxidant activity, 12,13) antiinflammation, 14) cytotoxicity, and antitumor effects. [15][16][17][18] Here we describe the isolation and effects of six diarylheptanoids (1-6) from the stem bark of A. hirsuta on LPS-induced NFkB activation, on nitric oxide (NO) production, and on tumor necrosis factor-a (TNF-a) production in LPS-stimulated RAW264.7 cells. MATERIALS AND METHODS Plant MaterialThe stem bark of Alnus hirsuta TURCZ. was collected at Yangu, Kangwon, Korea in Aug. 2002 and the plant was identified by one of the authors, Prof. KiHwan Bae. The voucher specimen (CNU-0304) has been deposited at the herbarium of Chungnam National University, Daejeon, Korea.General Experimental Procedures Optical rotations were measured by JASCO DIP-370 digital polarimeter. IR spectra were taken on a JASCO Report-100 spectrometer (KBr pellet). FAB-MS were obtained using a JEOL JMS-DX 300 spectrometer.1 H-NMR (300 MHz), 13C-NMR (75 MHz), and DEPT data were obtained on a Varian Unity NMR spectrometer. High-performance liquid chromatography (HPLC) was ca...

show abstract

mentioning

confidence: 99%

Diarylheptanoids from Alnus hirsuta Inhibit the NF-kB Activation and NO and TNF-.ALPHA. Production

Jin

Cai

et al. 2007

Biological & Pharmaceutical Bulletin

View full text Add to dashboard Cite

show abstract

“…Compounds isolated from Alnus plants include numerous diarylheptanoids along with triterpenoids. [6][7][8][9][10] Many kinds of diarylheptanoids have also been isolated from Zingiberaceae [11][12][13] and Betulaceae plants, including some which showed inhibitiory activity toward cyclooxygenase-2, 14) and antiemetic activity. 15) Curcumin, one of the best known diarylheptanoids, has various biological properties including anticancer, 16) antiinflammatory 17) and antioxidative activities.…”

mentioning

confidence: 99%

New Diarylheptanoids from Alnus japonica and Their Antioxidative Activity

et al. 2005

View full text Add to dashboard Cite

“…The atropisomerism of the valoneoyl biphenyl bond was determined to be S by observation of a positive Cotton effect at 222 nm and negative Cotton effect at 259 nm in the CD spectrum (Okuda et al, 1982). Furthermore, enzymatic hydrolysis of 1 with tannase yielded gallic acid and a hydrolysate, which was identified as 4,6-(S)-valoneoyl-D-glucose by comparison of the physical and 1 H-NMR data (Hatano et al, 1990;Lee at al., 1992). Based on these spectroscopic and chemical results, the structure of 1 was concluded to be 2-O-galloyl-4,6-O-(S)-valoneoyl-D-glucose.…”

Section: Resultsmentioning

confidence: 99%