Parietin

Parietin
IUPAC name 1,8-dihydroxy-6-methoxy-3-methyl-anthracene-9,10-dione
Systematic name 1,8-dihydroxy-3-methoxy-6-methylanthraquinone
Other names Physcion(e), rheochrysidin, methoxyemodin
Identifiers
CAS number	521-61-9
PubChem	10639
Jmol-3D images	Image 1
SMILES Oc1cc(OC)cc(C2=O)c1C(=O)c3c2cc(C)cc3O
InChI InChI=1/C16H12O5/c1-7-3-9-13(11(17)4-7)16(20)14-10(15(9)19)5-8(21-2)6-12(14)18/h3-6,17-18H,1-2H3
Properties
Molecular formula	C16H12O5
Molar mass	284.26348 g/mol
Appearance	Orange/yellow
Related compounds
Related compounds	Emodin
Y (verify) (what is: Y/N?) Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
Infobox references

Parietin is the predominant cortical pigment of lichens in the genus Caloplaca, a secondary product of the lichen Xanthoria parietina, and a pigment found in the roots of Curled Dock (Rumex crispus). It has an orangy-yellow color and absorbs blue light.

It reacts with KOH to form a deep, reddish-magenta compound.

It has also shown anti-fungal activity against barley powdery mildew and cucumber powdery mildew, more efficiently in the latter case than treatments with fenarimol and polyoxin B.

References

• Caloplaca coralloides chemistry
• Choi, Gyung Ja; Seon-Woo Lee, Kyoung Soo Jang, Jin-Seog Kim, Kwang Yun Cho and Jin-Cheol Kim (December 2004). "Effects of chrysophanol, parietin, and nepodin of Rumex crispus on barley and cucumber powdery mildews". Crop Protection 23 (12): 1215–1221. doi:10.1016/j.cropro.2004.05.005. 
• Edwards, Howell G. M.; Emma M. Newton, David D. Wynn-Williams, and Steven R. Coombes (2003-03-12). "Molecular spectroscopic studies of lichen substances 1: parietin and emodin". Journal of Molecular Structure 648 (1-2): 49–59. doi:10.1016/S0022-2860(02)00384-8. 
• Solhaug, Knut A.; Yngvar Gauslaa (November 1996). "Parietin, a photoprotective secondary product of the lichen Xanthoria parietina". Oecologia 108 (3): 412–418. doi:10.1007/BF00333715.