The Asian plum or umeboshi could be the next natural product to help treat cardiac diseases, according to reseach presented at this week's meeting of the American Physiological Society.
Pickled plums are extremely popular in Japan, and have been reported to aid the digestive system, increase saliva, and even act as a cure for a hangover. Consumers today rub bainiku-ekisu, an extract made from the flesh of the plum, to the cheek or forehead in the belief it cures their toothaches and headaches.
A recent study also reported that a fruit juice concentrate of Asian plum improves human blood fluidity and identified a bioactive substance in it as Mumefral, which is produced during the plum processing.
Two physiologists from Vanderbilt University and a collaborator from Wakayama University (Japan) focused on bainiku-ekisu as a preventative treatment for various diseases. They discovered that in addition to the effect of bainiku-ekisu on blood fluidity, it may have a direct effect on the vasculature, and thereby improve cardiovascular diseases such as hypertension and/or atherosclerosis.
The scientific community has previously reported that the epidermal growth factor (EGF) receptor transactivation and subsequent extracellular signal-regulated kinase (ERK/MAP kinase) activation play central roles in signal transduction and gene expression of the AT1 receptor that leads to abnormal growth of vascular smooth muscle cells (VSMCs). The US researchers and their Japanese colleague started from the hypothesis that bainiku-ekisu might prevent cardiovascular diseases by blocking the EGF receptor transactivation. They investigated the effects of bainiku-ekisu on AngII-induced EGF receptor transactivation, ERK activation and protein synthesis in cultured aortic VSMCs in order to show the potential efficacy of bainiku-ekisu in reducing cardiovascular diseases.
They discovered that bainiku-ekisu effectively inhibited AngII-induced EGF receptor transactivation and its downstream ERK activation, resulting in marked suppression of protein synthesis induced by AngII. Furthermore, bainiku-ekisu had no noticeable non-specific effect on AngII-induced intracellular Ca2+ elevation or basal protein synthesis.
The data supports their hypothesis that bainiku-ekisu may be beneficial against hypertension and atherosclerosis by selectively inhibiting growth promoting signals of AngII in the vasculature.Bainiku-ekisu contains large amount of the known acids (citric acid, malic acid), as well as relatively small amounts of bioactive substances, such as Mumefural, produced in the manufacturing process. Given that a small amount of Mumefral has a strong potency to improve blood fluidity equal to a large amount of bainiku-ekisu, the authors speculated that Mumefural may also inhibit EGF receptor transactivation.