Abstract
Salam (Syzygium polyanthum), stevia (Stevia rebaudiana), tea (Camellia sinensis), and yakon (Smallanthus sonchifolius) leaves act as inhibitors of the α-glucosidase enzyme. The aims of this research were to (i) determine the best combination of polyherbals that could inhibit the α-glucosidase enzyme, (ii) determine the phytochemical content of the teraactive fraction, and (iii) predict potential bioactive compounds that were responsible for the inhibition of the α-glucosidase enzyme. The novelty of this research was its use of several types of herbs, combined with various compositions, to obtain the IC50 value. Also, this research predicted the activity of the compound through a molecular docking approach with Molegro Virtual Docker software. The extraction was carried out with the maceration method with 96% ethanol and then partitioned with ethyl acetate and water. Two fractions with high inhibition percentages were combined with a ratio of 1:1, 1:2, 2:1, 1:3, and 3:1, and they were tested against the α-glucosidase inhibitory enzyme. The best fraction was identified for chemical compound content by Liquid Chromatography Mass Spectroscopy (LC-MS/MS). The compounds were analyzed in silico by using Molegro Virtual Docker software, which obtained the best reranc score. The results showed that the ethanol extract of tea leaves had the highest activity, at 65.51%, and salam, stevia, and yakon leaves had inhibition percentages of 44.11%, 34.74%, and 28.85%, respectively. The combination of water fractions of tea and salam leaves had the best activity at a ratio of 3:1 with IC50 of 16.53 ppm, which was almost equivalent to acarbose as a positive control with IC50 of 14.62 ppm. The analysis of LC-MS/MS for the water fraction of tea contained nicotiflorin with m/z 594, a reranc score of -118.24, and amino acid residues Arg, Asp, Asn, Cys, Glu, His, Thr, and Tyr. The water fraction of salam leaves contained quercetagetin with m/z 319, the reranc score was –89.123, and the amino acid residues Asn, Asp, Gln, Lys, Phe, Pro, Thr, and Trp.