2(C₁₉H₁₈O₈)-4 OH₂ = C₃₈H₂₈O₁₂.
Catechin, by melting it with caustic potash, affords Protocatechuic acid, C₆H₃(OH)₂COOH, and Phloroglucin, C₆H₃(OH)₃:
C₁₉H₁₈O₈ + 2 OH₂ = 4 H · C₇H₆O₄ · 2 C₆H₆O₃.
Gautier (1877) also obtained the two latter products, but he is of the opinion that they are due to a somewhat different reaction, the formula of catechin, as derived from his analyses, being C₂₁H₁₈O₈. He also asserts that the so-called catechin from Uncaria (see Gambier) is not identical with the substance under notice, nor with that found in the Mahogan wood, to which Gautier assigns the formula C₄₂H₃₄O₁₆.
Crystallized deposits of catechin are sometimes met with in fissures of the trunk of Acacia Catechu, and used medicinally in India under the name Keersal.[936]
Löwe (1873), by exhausting cutch with cold water and then agitating the solution with ether, obtained upon the evaporation of the latter a yellow crystalline substance which he ascertained to be Quercetin, C₂₇H₁₈O₁₂. Its solubility in water is probably favoured by the presence of catechin, water having but very little action upon pure quercetin. The amount of quercetin in cutch is exceedingly small.
When either cutch or gambier is subjected to dry distillation it yields, in common with many other substances, Pyrocatechin, C₆H₄(OH)₂.
Commerce—The importations of cutch into the United Kingdom from British India (excluding the Straits Settlements and Ceylon) were as under, almost the whole being from Bengal and Burma:—
| 1869 | 1870 | 1871 | 1872 |
| 2257 tons. | 5252 tons. | 4335 tons. | 5240 tons. |
The total value of the cutch imported in 1872 was estimated at £124,458.