Onion Foreign Literature Review

CHAPTER 2
RELATED STUDIES AND LITERATURE
This chapter includes the necessary and important information from both local and foreign literatures and studies in the Hair Growth Property of the Semi-Purified Flavonoid from the peel of Allium cepa Linn. Family Alliaceae in Female Swiss Mice.
Foreign Literature
Onion is a member of the Allium Family which is rich in sulfur-containg compounds that are responsible for its unpleasant odor and for many of its health-promoting effects. Onion is composed of a wide variety of allyl sulfides. It includes the four major diallyl sulfides which are: DMS (diallylmonosulfide), DDS (diallyl disulfide), DTS (diallyltrisulfide), and DTTS (diallyltetrasulfide). A wide variety of sulfoxides, including (+) S-methyl-L-cysteine sulfoxide (MCSO), (+)-S-(1-propenyl)-L-cysteine sulfoxide (PRENCSO), S-methyl-l-cysteine sulfoxide, S-propyl-l-cysteine sulfoxide, and S-propenyl-l-cysteine sulfoxide are also present in Onion. Onions are known for its polyphenol component, including the flavonoid polyphenols. Because of its flavonoid category, onions are a standout source of quercetin.1
Flavonoids and organosulfur compounds are the two major classes of secondary metabolites found in onions believed to promote beneficial health effects. Their mode of action and biosynthetic pathways are quite different. Flavonoids are phenolic

First is the Anagen phase where the active hair growth occurs. Then the Catagen phase, the hair shaft detaches from the dermal papilla and moves and the hair follicle contracts and moves upwards. The last stage is the Telogen phase which is also known as the resting phase, hair is shed and a new growing hair starts to form at the base of the hair follicle to enter into another hair growth cycle. The hair in the scalp doesn’t go through the same cycle at the same time. It is normal to shed 50 to 100 hair strands per day. Beyond this number is considered excessive hair