Propolis recently been isolated from red propolis, and prenylated acids such as 4-hydroxy-3,5-diprenyl cinnamic acid have been documented. An analysis of propolis from Henan, China found sinapinic acid, isoferulic acid, caffeic acid, and chrysin, with the first three compounds demonstrating antibacterial properties. Also, Brazilian red propolis, largely derived from "Dalbergia ecastaphyllum" plant resin, has high relative percentages of the isoflavonoids 3-hydroxy-8,9-dimethoxypterocarpan and medicarpin. Other flavonoids commonly present include galangin and pinocembrin. Caffeic acid phenethyl ester (CAPE) is also a component of some varieties of propolis from New Zealand. Occasionally, worker bees will even gather various caulking compounds of human manufacture, when
Animal glue or priming of oil painters' canvases. It also is used in bookbinding and as the adhesive component of some recipes for gesso and compo. Animal glue An animal glue is an adhesive that is created by prolonged boiling of animal connective tissue. These protein colloid glues are formed through hydrolysis of the collagen from skins, bones, tendons, and other tissues, similar to gelatin. The word "collagen" itself derives from Greek κόλλα "kolla", glue. These proteins form a molecular bond with the glued object. Stereotypically, the animal in question is a horse, and horses that are put down are often said