THE EFFECT OF. ANTIOXIDANTS ON THE PARA- AMINOBENZOIC ACID PHOTOSENSITISED FORMATION OF THYMINE DIMER AND SINGLET. MOLECULAR OXYGEN

ningependa kuwakumbusha machache. Kwanza ni kuwa hakuna kiumbe aliyekamilika lakini uchaji Mungu ndiyo kilele cha hikma. Pili, subra ni ibada kama ibada nyenginezo. Mwisho ni kuwa "mvumilivu hula mbivu " na "Panapo nia pana njia." On exposure to UV radiation DNA is damaged. The thymine cyc10butane dimer is one of the most significant of the lesions formed. This dimer is associated with the mutagenic and carcinogenic effect of UV radiation. It has been shown to cause skin cancer. Thymine dimerisation can be effected by direct irradiation or via an endogenous photosensitiser that is involved in energy transfer. This deleterious effect of UV radiation has prompted the use of sunscreens as photoprotectants. Para-aminobenzoic acid (PABA) is an active ingredient that was once widely used in sunscreen formulations. Reports of allergic reactions and staining by PABA have led to the discontinuation of its use in sunscreen