Reversible changes of canavalin solubility controlled by divalent cation concentration in crude sword bean extract

Edible Sword Bean Extract Induces Apoptosis in Cancer Cells In Vitro and Inhibits Ascites and Solid Tumor Development In Vivo

Antitumor potential of edible sword bean (Canavalia gladiata (L.)) extract has been evaluated against Daltons lymphoma ascites (DLA) using in vitro and in vivo studies. Methanolic extraction was carried out and in vitro studies were performed against both DLA and A549, lung cancer cell lines. The results revealed that sword bean extract inhibited cell growth and induced apoptosis as evidenced by cytotoxic assay, Hoechst 33342 staining and acridine orange/ethidium bromide dual staining. In vivo studies performed on DLA induced solid as well as ascitic tumors models showed administration of sword bean extract (10 mg/kg B.wt.) could significantly inhibit ascitic and solid tumor development in mice. Therefore, our overall results revealed that C. gladiata treatment could significantly inhibit tumor development and induce apoptosis in tumor cells.

Honey-mediated aggregation of soymilk proteins

Gluconic acid, the major organic acid in honey, is a partial hydrolysate of glucono-δ-lactone, typically used as a coagulant in preparing tofu. The present study aimed to examine the coagulation potential of five different types of honey at different concentrations, upon addition to soymilk. In some samples, aggregates formed in the upper layer at a higher honey concentration, while in others, aggregates precipitated at an intermediate honey concentration. Both phenomena were reproduced by adding different mixtures of glucono-δ-lactone and glucose, indicating that gluconic acid concentration and total sugar content of honey can trigger soymilk coagulation. Interestingly, honeys with a high concentration of gluconic acid showed a low total sugar content. Furthermore, in a trial product, the mixture of blended honey with soymilk was determined to be pasty. Our results indicate that honey can coagulate soymilk, which may provide a new and convenient method to prepare soymilk-based industrial products.

Structural transitions of sword bean canavalin in response to different salt concentrations

Canavalin is the major storage protein in sword beans (Canavalia gladiata) and belongs to the 7S seed globulin class. Canavalin solubility can be reversibly altered via the addition of MgCl₂ and CaCl₂ at different concentrations; specifically, it is insoluble at lower concentrations and soluble at higher concentrations. However, the addition of NaCl does not induce the insolubilization of canavalin. In this study, it was determined that the addition of NaCl causes the nearly complete solubilization of MgCl₂-precipitated canavalin in the presence of high concentrations. Moreover, using gel filtration we examined the quaternary structures of soluble canavalin in the bean extract and in the presence of high-concentration salts. Results indicated that canavalin was present in the monomer form within crude extracts with distilled water. Alternatively, we identified trimeric soluble canavalin in the presence of high concentrations of NaCl or MgCl₂. Our study revealed that the quaternary structures of sword bean soluble proteins differ in crude extract compared to those in high-concentration salt solutions. The three-dimensional structure of β-conglycinin, which is a typical 7S-seed globulin in soybean, has a trimer form in the presence of high concentrations of NaCl. However, it remains unclear whether β-conglycinin is present as trimers in soybean seed. Our findings serve as an important reference to analyze 7S globulin characteristics.

Sword bean variants and different pretreatments influence protein extraction and protein properties

Two variants of the sword bean (Canavalia gladiata), namely the white sword bean (WSB) and the red sword bean (RSB), are known. The MgCl₂ concentration-dependent canavalin solubility showed different behavior among the extracts from distinct beans prepared by distinct pretreatments. Pretreatment and bean selection are important factors for use in food chemical and biochemical experiments.

A crude sword bean (Canavalia gladiata) extract is gelated by cooling

White sword bean (Canavalia gladiata) seeds have the potential to be utilized in the manufacturing of processed foods owing to their high protein and carbohydrate content. Our previous reports explored the use of the sword bean as a source of food materials by preparing extracts in distilled water. In the present study, we found that one such extract can be gelated by cooling. The gelling substances were extracted by boiling and simultaneously stirring a suspension containing ground beans. Few proteins were present in the gelated extract. We also examined the conditions under which gelation occurred and the gel melting temperature. The extract gelated at temperatures below 10 °C, and the resulting gel melted at those above 65 °C. This is the first report that gelling substances can be extracted from sword beans in large quantities. We expect that this gelling agent can be used for the production of processed foods.