| Nutraceuticals are naturally occurring, bioactive chemical compounds that have health promoting, disease preventing or medicinal properties. Epidemiological studies have shown that certain components of fruits, vegetables, grains, and nuts may prevent or reduce the risk of some chronic diseases such as cancer and cardiovascular diseases. Among these food-derived Nutraceuticals, nuts have been reported to reduce the risk of various human diseases including coronary heart disease. Almond is the most popular tree nut in the USA with 70% of the world's supply. The consumption of almond has been reported to lower LDL cholesterol while preserving HDL cholesterol in human and to reduce colon cancer risk in animal.; Arachidonic acid metabolism is believed to play an important role in various human diseases such as inflammation and cancer. The enzymes participating in arachidonic acid metabolism as well as the metabolites, eicosanoids have been found at elevated levels in various human cancer cells.; An activity-guided fractionation of almond skin was carried out using various column chromatographic techniques and biological assays including antioxidant and arachidonic acid release inhibition assays. Several fractions from almond skin extract have strong antioxidant activities. In addition, some fractions showed significant inhibition of arachidonic acid metabolism in the HT-29 human colon cancer cell both at the enzymatic level as well as in intact cell line. Several analytical tools have revealed that the active fraction of almond skin contains significant amount of proanthocyanidins. Various techniques such as depolymerization reaction and LC-MS have shown that the proanthocyanidin purified from almond skin has a polymer structure with (−)-epicatechin as an extension unit and with the polymerizatioin degree of 5 or higher. The almond skin proanthocyanidin significantly inhibited arachidonic acid release in HT-20 cell at levels as low as 1 μg/ml and showed stronger DPPH radical scavenging activity than BHT at 10 ppm.; These results indicate that almond skins serve as an overlooked source of nutraceuticals in particular their antioxidant and arachidonic acid cascade inhibitor properties. |
