Essential growth factor for microorganisms. It forms part of the molecule of folic acid and is therefore required for the synthesis of this vitamin. Mammals cannot synthesise folic acid, and PABA has no other known function; there is no evidence that it is a human dietary requirement. Not normally present in human diets, can be used to validate 24 h urine collections, because an oral dose, given at each of three meal-times, is rapidly and quantitatively excreted in the urine.
Growth factor (probably co-enzymic) in the metabolism of some micro-organisms, and antagonistic to sulphanilamide, for one or both of which reasons it may be added to culture media, particularly blood culture broths.
The active ingredient in many sunscreens and sunblocks; also known as PABA. Products that contain para-aminobenzoic acid resist being diluted by sweat and water. However, people who have sensitive or allergy-prone skin are advised to choose PABA-free products.
A naturally occurring drug used in lotions and creams to prevent sunburn. It was formerly administered by mouth to treat certain infections now treated with antibiotics. High doses may cause nausea, vomiting, itching, and rashes.
A chemical once the primary component in numerous sunscreen formulas, but its use has become infrequent in recent times.