Sanguinarine levels in biological samples by high-performance liquid chromatography.

A high-performance liquid chromatographic method is presented for the analysis of the benzophenanthridine alkaloid, sanguinarine, found in plant extracts. The method is demonstrated to be applicable to analyzing samples such as saliva and gingival crevicular fluid for sanguinarine following a simple acidified methanolic extraction step. The method utilizes an ethyl silane column with acidic and basic ion-pairing reagents in the mobile phase with a limit of detection of 3 ng of sanguinarine in a sample.

Isolation and characterization of a folate receptor from human placenta.

While folate binding proteins have been described in serum and a variety of tissues, the function of these proteins is unknown. A particulate folate binding protein from human placenta has been isolated and characterized following solubilization with Triton X-100. The protein was purified 61,000-fold using affinity chromatography on pteroylglutamic acid-Sepharose as the major purification step. On sodium dodecyl sulfate-polyacrylamide gel electrophoresis the purified protein gave a single band with a Mr = 38,500. Stoichiometry of binding indicated that 1 mol of folate was bound per mol of protein. The protein was a glycoprotein that contained 12% carbohydrate. Antiserum was raised in a rabbit, and on immunodiffusion, gave a single precipitin line with the purified placental folate binding protein. Immunoprecipitation studies using this antiserum indicated that the purified placental folate binding protein shared antigenic determinants with both the large Mr and small Mr folate binding proteins from human milk. Immunofluorescent studies with this antiserum and human erythrocytes revealed the presence of an immunologically similar protein on the plasma membrane of these cells suggesting that this protein may function as a folate receptor.