Anatomical and physical changes in leaves during the production of tamales.

PREMISE OF THE STUDY: Tamale preparation has a long tradition in Mexico. To understand which material properties have been considered important for this purpose throughout the years, a study was conducted of the anatomical, chemical, and mechanical properties of the leaves of four plant species used in tamale preparation in Veracruz, Mexico: Calathea misantlensis, Canna indica, Musa paradisiaca, and Oreopanax capitatus. METHODS: Four cooking treatments were considered: fresh (F), roasted (soasado, R), steamed (S), and roasted plus steamed (R/S). Chemical, anatomical, and mechanical analyses were conducted before and after each treatment. Leaf samples were tested for tensile strength at both parallel and perpendicular orientation relative to the fibers. KEY RESULTS: Musa paradisiaca had the highest proportion of cellulose, while the remaining species shared similar lower proportions. Leaves were stronger and stiffer in the longitudinal direction of the fibers. Musa paradisiaca leaves had higher values of mechanical strength than the other species. The cooking process that most affected the mechanical properties was steaming. CONCLUSIONS: The chemical constituents of the leaves are closely correlated with their physical properties. The treatment that caused the greatest decrease in leaf physical integrity was steaming, while the combination of roasting and steaming showed similar results to those of steaming alone. No evident anatomical changes are produced by any of the treatments. This is one of the few studies comparing physical, chemical, and anatomical characteristics of leaves used for human consumption, before and after cooking.

Dendropanax morbifera Branch Water Extract Increases the Immunostimulatory Activity of RAW264.7 Macrophages and Primary Mouse Splenocytes.

Polyacetylenes in the bark of Dendropanax morbifera trees have been reported to promote immune cell proliferation and to strengthen the innate immune system. The immunomodulatory potential of D. morbifera branch water extract (DBW) was evaluated by determining its effect on cell viability and the expression of cytokines and immune effector molecules in mouse RAW264.7 macrophages and splenocytes. Production of nitric oxide (NO), inducible nitric oxide synthase (iNOS), and cytokines (interleukin [IL]-1ß, IL-2, and IFN-γ) in RAW264.7 macrophages increased after treatment with DBW. The activation of components of the NF-κB signaling pathway, including the phospho-IκBα and the expression and translocation of p65, a subunit of NF-κB, were also increased in RAW264.7 mouse macrophage cells after treatment with DBW. In addition, when mice were orally administered DBW, splenocyte cytokines and NO production were increased in a dose-dependent manner relative to control-treated mice. Furthermore, natural killer cell activity in DBW-treated mice was determined by lactate dehydrogenase (LDH) release assay. LDH release also increased in response to DBW treatment. Taken together, these results indicate that D. morbifera extract enhances innate immunity by promoting NF-κB signaling, leading to increased expression of proinflammatory cytokines and effector molecules. DBW therefore has potential therapeutic use in the context of immune stimulation.