The amla powder at Mountain Rose Herbs says that it has abscorbic acid in it?
"Constituents
Ascorbic acid, tannins, polyphenols, flavonoids, kaemferol, ellagic acid, gallic acid. Dehydrated amla is considered to have a considerably higher Vitamin C (ascorbic acid) content than traditional drying methods"
Hopefully herb suppliers aren't watering down their herbal superfoods. I remember seeing 'pure' Acerola Cherry Powder at Pacific Botanicals not too long ago.