(+/-)-Catechin is a potent phytotoxin, with the phytotoxicity due entirely to the (-)-catechin enantiomer. (+)-Catechin, but not the (-)-enantiomer, has antibacterial and antifungal activities. Tetramethoxy, pentaacetoxy, and cyclic derivatives of (+/-)-catechin retained phytotoxicity. The results indicate that antioxidant properties of catechins are not a determining factor for phytotoxicity. A similar conclusion was reached for the antimicrobial properties. Centaurea maculosa (spotted knapweed) exudes (+/-)-catechin from its roots, but the flavanol is not re-absorbed and hence the weed is not affected. The much less polar tetramethoxy derivative may, however, be absorbed and hence be able to cause toxicity. Because of the combination of phytotoxicity and antimicrobial activity, (+/-)-catechin could be a useful natural herbicide and antimicrobial.
(±)-
儿茶素是一种强效植物毒素,其植物毒性完全来自于
(-)-儿茶素对映体。(+)-
儿茶素具有抗菌和抗真菌活性,而(-)-对映体则不具备这些活性。四甲氧基、五乙酰氧基以及(±)-
儿茶素的环状衍
生物保留了植物毒性。这些结果表明,
儿茶素的抗氧化性并非决定其植物毒性的关键因素。对杀菌活性的结论也类似。Centaurea maculosa(斑点
水钟花)从其根部释放(±)-
儿茶素,但由于该黄烷醇不会被重新吸收,因此不会影响该植物。然而,极性较低的四甲氧基衍
生物可能会被吸收,从而造成毒性。由于同时具备植物毒性和抗菌活性,(±)-
儿茶素可能是一种有用的天然
除草剂和抗菌剂。