The determination of vitamin B12 in comfrey and comfrey products


Briggs, D.R.; Ryan, K.F.; Bell, H.L.

Proceedings of the Nutrition Society of Australia 6: 148

1981


On average for 4 samples, fresh comfrey (Symphytum sp.) had vitamin B-12 in mature leaf 3.7 to 8.4, mean 6.3, in mature stem 2.4 to 4.2, 2.9 and in root 1.9 to 3.1, 2.6 ng/g. For 5 or 6 samples, commercial comfrey "tea" had 2.7 to 4.0, 3.4, tea bags had 1.6 to 3.5, 2.9 and tablets had 0.8 to 1.6, 1.2 ng/g.