Flavonoids are group of natural products that are widely present in plants. Most ﬂavonoids are present in the form of O-or C-glycosides and a small portion are in the form of aglycone. Flavonoids exist in almost all studied species in the plant kingdom, and play an important role in plant growth, blossoming, fruit bearing, and disease and bacteria defence, etc. Many monographs about ﬂavonoids have been published[1-7]. In the last 10 years, ﬂavonoid research has turned more to the development of medical value, extraction and isolation technology, assay determination, and production of ﬁnished dosage forms.