"Isoflavones from both soy and Osage orange recently have been demonstrated by other laboratories to protect brain cells, or neurons, from the toxic effect of amyloid beta peptide. Amyloid beta peptide is believed to be responsible for the degeneration of neurons in Alzheimer's patients. However, the precise mechanisms by which isoflavones block the toxicity of amyloid beta peptide are unknown. Soybeans contain less than one-tenth of one percent isoflavone compounds, Whaley said. By comparison, between 5 percent and 10 percent of the dry mass of a bois d'arc apple is composed of isoflavone compounds. This plant has somehow developed the ability to produce extraordinary high levels of isoflavone compounds," Whaley said. "There is no known dietary plant that contains this high level of isoflavones.Whaley's research is focused on determining the molecular structure of the unique kind of isoflavones found in the Osage orange and on identifying the enzymes, and the genes that encode them, that are responsible for producing these compounds. Once the genes are identified and cloned, it may be possible to insert these genes into other, more palatable dietary plants, or forage plants eaten by livestock, he said.There are different kinds of isoflavones, each with their own unique structure," Whaley said. "The ones in the Osage orange have a peculiar structure that makes them very water insoluble. But they could be used as precursors in the chemical synthesis of other ingestible isoflavones.Whaley is particularly interested in how isoflavones protect brain cells from the toxic effects of the amyloid beta protein, which travels through the blood stream by hitching a ride within low-density lipoprotein, or LDL, particles. Whaley's recent research has focused on how isoflavones get inside, or partition into, lipid structures called micelles. These micelles are simple lipid structures that are chemically similar to LDL particles. To study the mechanisms for how isoflavones get inside the LDL particles in the body, Whaley has used micelles as a simple model. He adds a special detergent to water that forms micelles, and by adding isoflavones to the mix, he can then observe how the isoflavones position and orient themselves within the micelle structure. The position and orientation of isoflavones is a key consideration in understanding how they protect lipid structures from reactive oxygen species, which are also called free radicals. It is the reactivity of free radicals that ultimately is responsible for the aging process. "The next step is to take the techniques we've developed for studying detergent micelles and translate those techniques into more complex models and eventually into cells," he said. "The mechanism by which isoflavones block neurotoxicity could be related to their ability to lodge into lipid membranes, because that is where the precursor to amyloid beta peptide is usually located. Understanding the basic structure of the isoflavones and their interaction with lipid structures hopefully will give us insight into how natural chemicals in fruits and vegetables may lower the risk for developing diseases such as Alzheimer's disease or atherosclerosis. "Coming up with a magic bullet to treat Alzheimer's disease is a long way off, but I think there's a chance of learning something through natural products such as the isoflavones produced by Osage orange. They probably will not provide an immediate drug, but understanding their biological activities may indicate an avenue of research for developing a new pharmaceutical."
Abstract: The fruit of the osage orange tree (Maclua pomifera [Raf.] Schneider) was shown to contain at least four pigments with antioxidant activity. Pomiferin was present as 3 to 4% of the dry fruit and, as a primary antioxidant, was responsible for 20-25% of the activity exhibited by methanol extracts. An unidentified substance was also present which reacted synergistically with pomiferin, increasing its contribution to the overall activity to approximately 75%. The three new pigments, totalling 0.5% to .75% of the dry fruit, all showed antioxidant activity exceeding that of pomiferin when tested at equal concentrations. A chromatographic procedure, employing anhydrous magnesium sulfate, was developed and applied successfully in separating mixtures of several iso-flavone pigments.
In Osage orange, osajin and pomiferin account for between 5 and 10 percent of the dry mass of the fruit tissue. This is an extraordinary amount of isoflavone and is much higher than the isoflavone content of soybean (approximately 0.1% by mass). Osajin and pomiferin were first isolated and characterized by researchers at The Ohio State University in the late 1930s. It appears from this study that a 90/10, v/v, methanol/water solvent was used to extract these isoflavones. O sajin and pomiferin have low solubility in solvent mixtures containing small amounts of water.
Abstract: The objective of the present 15-day study was to evaluate the cardioprotective potential of flavonoid pomiferin isolated from the infructences of Maclura pomifera , Moraceae, against ischemia-reperfusion induced injury in rat hearts as a model of antioxidant-based composite therapy. Studies were performed with isolated, modifi ed Langendorff-perfused rat hearts and ischemia of heart was initiated by stopping the coronary flow for 30 min, followed by 60 min of reperfusion (14 ml min-1 ). Wistar rats were divided into three groups. The treated group received pomiferin (5 mg/kg/day in 0.5% Avicel); the placebo group received only 0.5% Avicel; the intact group was left without any applications. Biochemical indicators of oxidative damage, lipid peroxidation product malondialdehyde, antioxidant enzymes (superoxide dismutase, glutathione peroxidase, total antioxidant activity in serum and myocardium has been evaluated. We also examined the effect of pomiferin on cardiac function (left ventricular end-diastolic pressure, left ventricular pressure, peak positive +dP/dt (rate of pressure development) after ischemia and reperfusion. Our results demonstrate that pomiferin attenuates the myocardial dysfunction provoked by ischemiareperfusion. This was confirmed by the increase in both the antioxidant enzyme values and the total antioxidant activity. The cardio-protection provided by pomiferin treatment results from the suppression of oxidative stress and correlates with the improved ventricular function.
Abstract: Recent findings that many human chronic diseases are associated with oxidative stresses have instigated the search for dietary antioxidants. Many phytochemicals, particularly phenolic compounds, have been found to possess strong antioxidant activity and reduce the risks of those diseases. Isoflavones, a special phenolic group found in soybean, have been found to act as antioxidants in some model systems. This study investigated the isoflavone content in a unique nonedible tree fruit, Osage orange [Maclura pomifera (Raf.) Schneid], and methods for the extraction, identification, and quantification of the two major isoflavones, osajin and pomiferin, were developed. The ethyl acetate extract contained 25.7% osajin and 36.2% pomiferin, and the two isoflavones were at 9.5 g kg(-1) of fresh Osage orange. Two model systems, FRAP and beta-CLAMS, were used to measure the antioxidant activity of these two isoflavones. Pomiferin was found to be a strong antioxidant in both systems, comparable to the antioxidant vitamins C and E and the synthetic antioxidant BHT. Osajin and the two soybean isoflavones (genistein and daidzein) showed no antioxidant activity. Although the Osage orange fruit is not a food source, it is considered to be safe and, therefore, a potentially good source of an antioxidant nutraceutical and functional food ingredient.