The extract was immediately poured and placed in the refrigerator
until dark brown powder of cyanidin chloride precipitated. The
powder was filtered and dried in a desiccator. Then it was purified
through Sephadex LH-20 using methanol as eluent. Anthocyanins
were characterized by UV–vis spectrophotometry, NMR and mass
spectrometry. Shinoda’s method [29] was used to check the flavonoid
property by adding a piece of magnesium ribbon and 1 mL of
concentrated HCl into 2–3 mL of methanolic extract (pink red or
red coloration appeared after a few minutes).