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

Abstract

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 482 Volume 12, Nomor 2 (2025) Jurnal Pharmascience 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