Valoneic acid dilactone is a

hydrolysable tannin A hydrolyzable tannin or pyrogallol-type tannin is a type of tannin that, on heating with hydrochloric or sulfuric acids, yields gallic or ellagic acids. At the center of a hydrolyzable tannin molecule, there is a carbohydrate (usually D-glucose ...

that can be isolated from the heartwood of ''

Shorea laevifolia ''Shorea laevis'' is a species of tree in the family Dipterocarpaceae. It is native to Myanmar, Thailand, Sumatra, Peninsular Malaysia and Borneo Borneo (; id, Kalimantan) is the third-largest island in the world and the largest in As ...

''5A-Reductase inhibitory tannin-related compounds isolated from Shorea laevifolia. Yoshio Hirano, Ryuichiro Kondo and Kokki Sakai, Journal of wood science, Volume 49, Number 4, pp.339-343, and in oaks species like the North American white oak (''

Quercus alba An oak is a tree or shrub in the genus ''Quercus'' (; Latin "oak tree") of the beech family, Fagaceae. There are approximately 500 extant species of oaks. The common name "oak" also appears in the names of species in related genera, notably '' ...

'') and European red oak (''

Quercus robur ''Quercus robur'', commonly known as common oak, pedunculate oak, European oak or English oak, is a species of flowering plant in the beech and oak family, Fagaceae. It is a large tree, native plant, native to most of Europe west of the Caucasus ...

'').Analysis of oak tannins by liquid chromatography-electrospray ionisation mass spectrometry. Pirjo Mämmelä, Heikki Savolainenb, Lasse Lindroosa, Juhani Kangasd and Terttu Vartiainen, Journal of Chromatography A, Volume 891, Issue 1, 1 September 2000, Pages 75-83, It shows an inhibitory effect on 5α-reductase, an enzyme involved in steroids metabolism and prostate cancer.

References

External links

* Ellagitannins 5α-Reductase inhibitors Lactones Trihydroxybenzoic acids {{aromatic-stub