Citrus Limon (Lemon), Carica Papaya (Papaya Leaves) and Curcuma Longa (Turmeric): A Review on Its Phytochemistry and Dermatologic Applications

Hyperpigmentation remains a prevalent dermatological concern, prompting interest in natural alternatives to synthetic whitening agents such as hydroquinone. This review evaluates the phytochemical constituents and dermatological applications of Citrus limon (lemon), Carica papaya leaves, and Curcuma longa (turmeric) in skin whitening. C. limon contains ascorbic acid and flavonoids including hesperidin and eriocitrin, which exhibit direct tyrosinase inhibition and antioxidant activity that attenuates UV-induced melanogenesis. C. papaya Leaves provide proteolytic enzymes papain and chymopapain for enzymatic exfoliation of melanin-rich keratinocytes, alongside quercetin, a flavonoid with tyrosinase inhibitory and anti-inflammatory properties. C. longa contributes curcumin, which suppresses melanin synthesis via tyrosinase and MITF downregulation, and turmerone oil, which enhances bioavailability and provides additional antioxidant effects. Collectively, these plants demonstrate complementary, multi-target mechanisms—enzymatic desquamation, melanin synthesis inhibition, and photoprotection—that support their potential as a natural source of dermatological benefits for hyperpigmentation management. Despite promising in vitro and in silico evidence, limitations include phototoxicity risks from C. limon, staining and bioavailability issues with C. longa, and formulation stability challenges. Further clinical studies are warranted to validate optimal delivery systems for cosmeceutical applications.