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
Hoof glue glue is a hard block of resin-like material. To use it one would break off a suitably sized chunk and mix it with hot water and allow it to melt. Once melted it can be simmered to reduce to the appropriate thickness and then applied to the object in question. Very thin glue can be used as a resin coating to stiffen and strengthen cordage, such as chair backs and seats. Hoof glue is not waterproof, it can be dissolved by water, so moisture or even high humidity will affect it. But hoof glue does not become brittle when dry;