Pengaruh Variasi Konsentrasi Kolesterol terhadap Karakteristik dan Stabilitas Fisik serta Aktivitas Inhibisi Enzim Tyrosinase Emulgel Niosom Bakuchiol

Penuaan dini kulit kini semakin sering terjadi, bahkan pada usia muda, ditandai dengan melasma dan solar lentigines. Salah satu bahan aktif alternatif yang menjanjikan sebagai anti-aging adalah bakuchiol, senyawa monoterpenoid dari Psoralea corylifolia yang memiliki efektivitas mirip retinol namun dengan efek samping lebih ringan. Penelitian ini bertujuan untuk mengevaluasi pengaruh variasi konsentrasi kolesterol dalam sistem penghantaran niosom terhadap karakteristik fisik dan aktivitas penghambatan enzim tirosinase dari emulgel bakuchiol. Tiga formula niosom dengan kolesterol 20, 25, dan 30 µmol diformulasikan ke dalam emulgel. Evaluasi meliputi karakterisasi fisik (organoleptis, pH, daya sebar, daya lekat, viskositas), ukuran partikel, indeks polidispersitas (PDI), zeta potensial, serta uji aktivitas tirosinase menggunakan substrat L-DOPA, dengan kontrol negatif (emulgel basis) dan kontrol positif (produk komersial). Hasil menunjukkan seluruh formula stabil selama 90 hari. Formula F2 (25 µmol kolesterol) memiliki ukuran partikel terkecil (203,3 nm), PDI terendah (0,1624), dan zeta potensial mendekati -30 mV, menunjukkan stabilitas terbaik. Formula ini juga menunjukkan aktivitas inhibisi tirosinase tertinggi setelah kojic acid (57,297%) dan berbeda signifikan dibanding formula lain (p < 0,05). Dengan demikian, formula F2 dapat disimpulkan sebagai formulasi optimal, di mana konsentrasi kolesterol 25 µmol terbukti meningkatkan stabilitas dan efektivitas penghantaran bakuchiol sebagai agen anti-aging dan penghambat tirosinase.

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Premature aging of the skin is now more and more common, even at a young age, characterized by melasma and solar lentigines. One of the alternative active ingredients that promises to be anti-aging is bakuchiol, a monoterpenoid compound from Psoralea corylifolia that has an effect similar to retinol but with milder side effects. This research aimed to evaluate the effect of variations in cholesterol concentration in the niosome delivery system on the physical characteristics and inhibiting activity of the tyrosinase enzyme of bakuchiol emulgel. Three niosome formulas with cholesterol of 20, 25, and 30 μmol are formulated into emulgels. Evaluation included physical characterization (organoleptic, pH, dispersibility, adhesion, viscosity), particle size, polydispersivity index (PDI), zeta potential, and tyrosinase activity test using L-DOPA substrates, with negative control (emulgel base) and positive control (commercial product). The results showed that the entire formula was stable for 90 days. The formula F2 (25 μmol cholesterol) had the smallest particle size (203.3 nm), the lowest PDI (0.1624), and a potential zeta close to -30 mV, indicating the best stability. This formula also showed the highest tyrosinase inhibition activity after kojic acid (57.297%) and differed significantly from other formulas (p < 0.05). Thus, the F2 formula can be concluded as an optimal formulation, in which a cholesterol concentration of 25 μmol had been shown to improve the stability and effectiveness of bakuchiol delivery as an anti-aging agent and tyrosinase inhibitor.