It is an isomer of vanillic acid. Some of the nonflavonoid compounds present are protocatechuic, vanillic, and p-hydroxybenzoic acids. The main active ingredients are vanillin, 4-hydroxybenzoic acid, 4-hydroxybenzaldehyde and vanillic acid. Identified compounds under basic research include gallic acid, vanillic acid and catechins, as examples. Four phenolic glycosides including vanillic acid 4-O-beta-d-glucoside, glucosyringic acid, tachioside and isotachioside are reported. They include vanillyl alcohol, vanillin, vanillic acid, acetovanillon, vanillylmandelic acid, homovanillic acid, capsaicin, etc.