6-Metoxyflavonols from the aerial parts of Tetragonia tetragonioides (Pall.) Kuntze and their potential as anti-inflammatory agents

Tetragonia tetragonoides (Aizoaceae) has been used in Korean traditional medicine for treatment various diseases [1]. T. tetragonoides contains a variety of secondary metabolites such as flavonoids, alkaloids, and terpenes [2]-[5]. These compounds have been reported to treat ulcers and stomach cancer [1], [5]. However, pharmacological studies of T. tetragonoides on anti-inflammation is barely carried out. Therefore, the present study focused on the isolation and identification of active materials from this plant, as well as examination for the anti-oxidant and anti-inflammatory activities of the isolated compounds. Dried aerial parts of T. tetragonoides were extracted with 70% aqueous EtOH, and the concentrated extract was partitioned into EtOAc, n-BuOH, and H₂O fractions. As a result of repeated normal, reverse-phase, and Sephadex LH-20 column chromatographies on each fraction, four new flavonoids (2-4, 8) along with four known ones (1, 5-7) were isolated. The structures were determined using classical spectroscopic methods such as (NMR, IR, MS). All the compounds except compound 1 were isolated for the first time from T. tetragonoides in this study. Some compounds showed significant anti-oxidant and anti-inflammatory activity. Also quantitative analysis of contents 6-methoxyflavonols in the aerial parts of T. tetragonoides was conducted through HPLC-UV experiment. These results supported that the 6-methoxyflavonols isolated from the aerial parts of T. tetragonoides are potential as anti-oxidant and anti-inflammatory agents.

Fig. 1 6-Methoxyflavonols 1-8 isolated from the aerial parts of Tetragonia tetragonoides.

• References

• 1 Bae KH. Medicinal plants of Korea. Seoul: Kyohak Publishing; 2000
• 2 Aoki T, Takagi K, Hirata T, Suga T. Two naturally occurring acyclic diterpene and norditerpene aldehydes from Tetragonia tetragonoides . Phytochem 1982; 21: 1361-1363.
• 3 Lee KH, Park KM, Kim KR, Hong JK, Kwon HC, Lee KR. Three new flavonol glycosides from the aerial parts of Tetragonia tetragonoides . Heterocycles 2008; 75: 419-426.
• 4 Kato M, Takeda T, Ogihara Y, Shimizu M, Nomura T, Tomita Y. Studies on the structure of polysaccharide from Tetragonia tetragonoides . Chem Pharm Bull 1985; 33: 3675-3680.
• 5 Okuyama E, Yamazaki M. The principles of Tetragonia tetragonoides having anti-ulcerogenic activity. II. Isolation and structure of cerebrosides. Chem Pharm Bull 1983; 31: 2209-2219.