What are the main ingredients of yam?

Chemical composition: mannan, 3,4-dihydroxyphenylethylamine, phytic acid, allantoin, choline, dopamine, bataxine, 10 amino acids, glycoprotein, polyphenol oxidase. Tropism of nature and taste: sweet in taste and flat in nature. Enter spleen, lung and kidney meridians. Efficacy: invigorating spleen and stomach, promoting fluid production and benefiting lung, tonifying kidney and astringent essence. Indications: spleen deficiency, anorexia, chronic diarrhea, asthma and cough due to lung deficiency, nocturnal emission due to kidney deficiency, leukorrhagia, frequent micturition, deficiency heat and thirst quenching.