4-methylcatechol is a metabolite of homoprotocatechuic acid. It is both a substrate and a suicide inhibitor of Catechol 23-dioxygenase. 4-methylcatechol is known to induce the production of brain-derived neurotrophic factor (BDNF). Recent studies have suggested that a lack of brain-derived neurotrophic factor (BDNF) in the limbic system may cause neuropathic pain.

Non-acylated, major circulating isoform of ghrelin

1,3,6-Trihydroxy-2-methyl-9,10-anthraquinone-3-O-(6'-O-acetyl)-beta-D-xylopyranosyl-(1->2)-beta-D-glucopyranoside ( Compound 20) is a quinone compound that can be isolated from the roots and rhizomes of Madder.