Innovative Gel Mask A. jiringa (Jack) Nielsen: Effects of HPMC and Palm Stem Starch on Physical Characteristics and Antibacterial Activity

Abstract

Kulit jengkol (A. jiringa (Jack) Nielsen) merupakan hasil samping pertanian yang belum memiliki nilai ekonomis tinggi, namun diketahui memiliki aktivitas antioksidan dan antibakteri yang kuat. Potensi ini mendasari pengembangan masker gel antijerawat sebagai sediaan topikal kosmetik. Penelitian ini bertujuan untuk mengevaluasi pengaruh kombinasi hidroksipropilmetilselulosa (HPMC) dan pati batang kelapa sawit terhadap karakteristik fisik serta aktivitas antibakteri masker gel A. jiringa terhadap Propionibacterium acnes. Ekstrak diperoleh melalui metode maserasi dan diuji aktivitas antibakterinya pada konsentrasi 0,25%, 0,30%, 0,35%, dan 0,40%. Konsentrasi optimum yang menunjukkan daya hambat tertinggi diformulasikan ke dalam masker gel dengan rasio HPMC:pati pada Formula 1 (1:2), Formula 2 (1:1), dan Formula 3 (2:1). Evaluasi meliputi viskositas, daya sebar, adhesivitas, pH, waktu kering, dan uji difusi sumur terhadap P. acnes. Hasil penelitian menunjukkan bahwa ekstrak A. jiringa 0,40% memiliki aktivitas antibakteri sedang dengan zona hambat 9,82 ± 0,06 mm. Ketiga formula gel memiliki warna cokelat muda, aroma khas minyak atsiri, tekstur halus dan homogen, viskositas antara 46,67 hingga 736,67 cps, daya sebar antara 4,75–8,92 cm, adhesivitas antara 11,52–17,68 detik, waktu kering 5,27–7,57 menit, serta pH berkisar antara 7,30–7,47. Disimpulkan bahwa kombinasi HPMC dan pati batang kelapa sawit mempengaruhi sifat fisik sediaan, namun tidak meningkatkan aktivitas antibakteri A. jiringa dalam sistem gel. Kata Kunci: A. Jiringa, P. Acnes, Antibakteri, Antijerawat, Pati Batang Kelapa Sawit  The peel of Archidendron jiringa (Jack) Nielsen, commonly known as jengkol, is an agricultural by-product with limited economic value but has been reported to possess strong antioxidant and antibacterial properties. This potential supports the development of an anti-acne gel mask as a topical cosmetic preparation. This study aimed to evaluate the effects of combining hydroxypropyl methylcellulose (HPMC) and palm stem starch on the physical characteristics and antibacterial activity of A. jiringa gel masks against Propionibacterium acnes. The extract was obtained through maceration and tested for antibacterial activity at concentrations of 0.25%, 0.30%, 0.35%, and 0.40%. The optimum concentration, which exhibited the highest inhibitory activity, was formulated into gel masks with different HPMC-to-starch ratios: Formula 1 (1:2), Formula 2 (1:1), and Formula 3 (2:1). Evaluations included viscosity, spreadability, adhesiveness, pH, drying time, and antibacterial activity using the well diffusion method against P. acnes. The results showed that the 0.40% A. jiringa extract exhibited moderate antibacterial activity with an inhibition zone of 9.82 ± 0.06 mm. All three gel formulations had a light brown color, a characteristic essential oil aroma, a smooth and homogeneous texture, viscosities ranging from 46.67 to 736.67 cps, spreadability between 4.75–8.92 cm, adhesiveness ranging from 11.52 to 17.68 seconds, drying time from 5.27 to 7.57 minutes, and pH values between 7.30 and 7.47. It was concluded that the combination of HPMC and palm stem starch influenced the physical properties of the gel formulations but did not enhance the antibacterial activity of A. jiringa in the gel system.