Paini Sri Widyawati, Yufita Ratnasari Wilianto
This study was done to determine the effects of steeping temperature and storage period on the bioactive contents plus antioxidant and antidiabetic activities of Pluchea leaf infusion. The research used a randomized block design with two factors, i.e. steeping temperature (T) and storage period (B). The Pluchea leaf blades were exposed to four steeping temperatures of 60 (T1), 70 (T2), 80 (T3), and 95 (T4) °C with the storage period of 0 (B1) and 5 (B2) yr – resulting in eight treatment combinations (T1B1, T1B2, T2B1, T2B2, T3B1, T3B2, T4B1, T4B2). Statistical analysis using a paired t-test at α ≤ 0.05 showed that treatments significantly affected the bioactive contents [total phenol (TPC), total tannin (TTC), and total flavonoid (TFC)], antioxidant [DPPH scavenging activity (DPPH) and ferric reducing antioxidant power (FRAP)] potential and antidiabetic [α-amylase (AA) and α-glucosidase (GA) inhibition] properties of the Pluchea leaf infusion. TPC, TTC, DPPH, and FRAP significantly increased for the storage period and the steeping temperatures. Then, TFC decreased during the storage period but significantly increased at higher steeping temperatures. The AA and GA of Pluchea leaf infusion increased until 70 °C of the steeping temperature but decreased until 95 °C. The DPPH and FRAP of the Pluchea leaf infusion were strongly and positively correlated with TPC and TTC. The GA and AA of Pluchea leaf infusion were not influenced by the TPC and TTC but were weakly and positively correlated with TFC. The antioxidant activity of the Pluchea leaf infusion was inversely proportional to the antidiabetic activity. The simple phenolic compounds derived from Pluchea leaf infusion at different steeping temperatures and storage included gallic acid, kaempferol, myricetin, (+)-catechin, quercetin, 3,4-di-O-caffeoylquinic acid, 3,5-di-O-caffeoylquinic acid, and 4,5-di-O-caffeoylquinic acid. © 2024, Department of Science and Technology. All rights reserved.
Food Technology Study Program, Agricultural Technology Faculty, Widya Mandala Surabaya Catholic University, Surabaya, 60265, Indonesia; Pharmacy Study Program, Pharmacy Faculty, Widya Mandala Surabaya Catholic University, Surabaya, 60272, Indonesia