Extraction Method and Crude Drug-to-Solvent Ratio Effects on the Antioxidant Properties and Physicochemical Profile during Storage of a Polyherbal Formulation Extract

Java tea, seed-under-leaf, and turmeric are well-known for their antioxidant activity. The mixture with 40% Java tea leaves, 55% seed-under-leaf aerial parts, and 5% turmeric rhizomes produced a polyherbal formulation with a satisfactory antioxidant profile. This study aimed to develop the optimal extraction condition to produce water extract with good antioxidant properties that are stable during storage. The herbal mixture was extracted using Decoction A, Decoction B, and infusion methods at crude drug-tosolvent ratios of 1:10, 1:20, and 1:100. The antioxidant activity was evaluated by the standard 2,2-diphenyl1-picrylhydrazyl (DPPH) scavenging activity and ferric reducing antioxidant power (FRAP) assays. The total phenolic content (TPC) and total flavonoid content (TFC) were determined according to the standard methods. The extract from Decoction A at a 1:10 ratio was stored for 18 days at 7±3°C, and their physicochemical properties, i.e., color, pH, DPPH scavenging activity, TPC, and TFC, were evaluated accordingly. The extraction method and crude drug-to-solvent ratio significantly affected the extracts’ DPPH scavenging activity, FRAP, TPC, and TFC. Decoction A at a 1:10 ratio yielded extracts with the highest DPPH activity, TPC, and TFC and total flavonoid content, while Decoction B at a 1:20 ratio resulted in the highest FRAP. Extracts from Decoction A at a 1:10 ratio underwent chemical changes on day 6 of refrigerated storage. In conclusion, extraction by Decoction A at a crude drug-to-solvent ratio of 1:10 produced an antioxidant-rich extract that remained stable for six days during storage.