Table 2.

Unconjugated curcuminoids present in the rhizome of C. longa

No.	Compound name	Structure	Reference
1	Curcumin		[52]
2	Demethoxycurcumin (DMC)
3	Bisdemethoxycurcumin (BDMC)
4	(1E,6E)-1-(3,4-dihydroxyphenyl)-7-(4- hydroxyphenyl)-1,6-heptadiene-3,5-dione		[53]
5	(1E,6E)-1,7-Bis(3,4-dihydroxyphenyl)-1, 6-heptadiene-3,5-dione (Didemethyl curcumin)		[54]
6	(1E,6E)-1-(3,4-dihydroxyphenyl)-7- (4-hydroxy-3-methoxyphenyl)-1, 6-heptadiene-3,5-dione (Monodemethylcurcumin)		[53, 55]
7	Curcumalongin C		[54]
8	(1E,6E)-1-(4-hydroxy-3,5-dimethoxyphenyl)-7-(4-hydroxy-3-methoxyphenyl)- 1,6-heptadiene-3,5-dione (5′-methoxycurcumin)		[55]
9	(1E,4E,6E)-1,7-bis(4-hydroxyphenyl)-1,4,6-heptatrien-3-one		[55]
10	(4Z,6E)-5-hydroxy-1,7-bis-(4-hydroxyphenyl)-4,6-heptadien-3-one		[53]
11	(6E)-3-hydroxy-1,7-bis (4-hydroxyphenyl)-6-heptene-1,5-dione		[53]
12	(4Z,6E)-1,5-dihydroxy-1,7-bis-(4-hydroxyphenyl)-4,6-heptadien-3-one		[53]
13	(4Z,6E)-1,5-dihydroxy-1-(4-hydroxyphenyl)-7-(4-hydroxy-3-methoxyphenyl)- 4,6-heptadien-3-one
14	(4Z,6E)-1,5-dihydroxy-1-(4-hydroxy-3-methoxyphenyl)-7-(4-hydroxyphenyl)- 4,6-heptadien-3-one
15	(4Z,6E)-1,5-dihydroxy-1,7-bis(4-hydroxy-3- methoxyphenyl)-4,6-heptadien-3-one
17	1,5-Bis(4-hydroxyphenyl)-1,4-pentadiene-3-one		[52]
18	(1E,4E)-1-(4-hydroxy-3-methoxyphenyl)-5-(4-hydroxyphenyl)-1,4-pentadien-3-one
19	(1E,4E)-1,5-bis(4-hydroxy-3- methoxyphenyl)-penta-1,4-dien-3-one
20	Curcumalongin A		[54]
21	Curcumalongin B
22	Cyclocurcumin		[56]