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
Glue-size high perishability of linen cloth and the solubility of hide glue. Well-known and relatively well-preserved — though substantially damaged — the most notable examples include Quentin Matsys' "Virgin and Child with Saints Barbara and Catherine" (c. 1515-25) and Dirk Bouts' "Entombment" (c. 1440-55). In German the technique is known as "Tüchleinfarben", meaning “small cloth colours”, or "Tüchlein", derived from the German words "Tüch" and "Lein" ("fabric" and "flax"). A binding agent for pigment was made by boiling animal skin mixed with other organic tissue and applied to linen, itself prepared with a thin layer of glue. The linen was ground,