Efficacy of topical soy Isoflavonoid extract in prevention and reversal of photo-ageing in guinea pig model

T Padmavathi, I Israel Raja Johnley, Prashanth Jeyabaskaran


Background: Photo aging is the superimposition of photodamage on intrinsically aged skin generally bringing about premature aging due to chronic and multiple exposure of the skin to UV light. Routinely used retinoids have many disadvantages. Phyto-estrogens present in plants have gained recent popularity as
anti-photo aging compounds. Isoflavonoids such as soy compounds can provide good photoprotection of human skin. We intended to study efficacy of topical preparation of isoflavones in guineapigs for treatment and prophylaxis of photoaging.
Materials and Methods: Three groups of guinea pigs were formed with 3 in each. Group II was pretreated with isoflavonoid. All the groups received irradiation with UV-B for 8 weeks. After irradiation Group I was treated with isoflavonoid and group II with tretinoin for 4 weeks. Erythema was scored with erythema scale before and treatment.
Results: Group II pre treated with isoflavonoid developed erythema only after 4 weeks where as other two groups developed in first week of irradiation. After treatment with isoflavonoids for 4 weeks, Group I guinea pigs recorded complete reduction in erythema from 3to 0. Group III which were treated with tretinoin recorded decline in erythema from 3 to 0.6. Guinea pigs of Group II had erythema score of 1 which persisted up to 8th week.
Conclusion: Isoflavonoid very well prevented erythema in guinea pig skin after UV-B irradiation. Topical isoflavonoid nullified erythema fully in phototoxicity. Efficacy of isoflavonoid is comparable to that of

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