Correct spelling for the English word "prunin" is [pɹˈuːnɪn], [pɹˈuːnɪn], [p_ɹ_ˈuː_n_ɪ_n] (IPA phonetic alphabet).
A substance made by evaporation from the tincture of Prunus serotina, wild cherry; employed in eclectic practice in the treatment of bronchial affections and in palpitation of the heart in doses of gr. 2-8 (0.13-0.5).
A practical medical dictionary. By Stedman, Thomas Lathrop. Published 1920.