ブラジリン

解説ブラジリン，C16H14O5(286.27)．マメ科スオウBrazilwoodやCaesalpiniasappanの心材から抽出される天然赤色染料．合成および光学分割もされている．黄色の結晶．(＋)-ブラジリンは融点250 ℃．[α]20D＋121.5°(メタノール)．エタノール，エーテルに可溶．アルカリに溶けて深紅色を呈するが，空気中，光で橙色に変色する．染料および酸塩基指示薬(pH 5.8，オレンジ→7.7，紫)として使用される．

説明Brazilin is an isoflavonoid originally isolated from C. sappan that has diverse biological activities, including neuroprotective, anti-inflammatory, antibacterial, and antioxidant properties. Brazilin inhibits Aβ (1-42) fibrillogenesis (IC50 = 1.5 μM) more potently than (-)-epigallocatechin gallate , cucurmin , and resveratrol. It also prevents remodeling of mature Aβ (1-42) fibrils. Brazilin inhibits the production of cytokines, including PGE2 and TNF-α (IC50s = 12.6 and 87.2 μM). It is effective against Gram-positive and Gram-negative bacteria with MICs ranging from 31.3 to 250 μg/ml. In addition, brazilin inhibits osteoclast differentiation mediated by RANKL and is protective against LPS-induced osteoporosis in mice at a dose of 100 mg/kg.Brazilin family of natural products.

使用inhibits platelet aggregation, PLA2, PKC, protein phosphatase, insulin receptor kinase, nitric oxide synthase, antineoplastic

純化方法Brazilin crystallises from EtOH as yellow crystals which become orange when exposed to light and air, and is yellow in dilute acid but crimson in dilute alkali. When crystallised from H2O, it has m 247-248o. It forms coloured metal salts and is oxidized in air to Brazilein the quinonoid form. The (±)-form has been resolved, and the (+)-enantiomer has [] 20 +121o (c 1, MeOH). [Craig et al. J Org Chem 30 1573 1965,Morsingh & Robinson Tetrahedron 26 281 1970, Beilstein 17 H 194, 17 II 244, 17 III/IV 2711.]