Purification of flavonoids from Carex meyeriana Kunth based on AHP and RSM: Composition analysis, antioxidant, and antimicrobial activity

Abstract Analytic hierarchy process (AHP) combined with response surface methodology (RSM) was used to optimize the purification processes of the crude flavonoids of Carex meyeriana Kunth (CMK). The bioactivities of flavonoids were evaluated in terms of antioxidant and antimicrobial activities. The weighted coefficients of comprehensive scoring method on AHP included recovery, purity, and decolorization rate. The optimal results were as follows: the sample concentration was 3.04 mg/mL, the ethanol concentration was 70.33 %, pH was 2.93, the elution velocity was 2.95 Bv/h, and the comprehensive score was 75.52 ± 0.53 % (n = 3). The purified flavonoids of CMK (PFCMK) were compared with a reference substance through ultra high-performance liquid chromatography and ultraviolet spectra. Results of composition analyses were as follows: (−)−gallocatechin, 5−Caffeoylquinic acid, (−)−naringin, myricetin, luteolin, and isorhamnetin. The IC50 values of 2,2–dIphenyl–1-picrylhydrazyl (0.034 mg/mL), hydroxyl radical method (0.643 mg/mL), and reducing power (0.025 mg/mL) showed that PFCMK had strong antioxidant activity. The minimum inhibitory concentrations on Bacillus pumilus, Bacillus subtilis, and Escherichia coli were 1.75, 1.75, and 0.875 mg/mL, respectively. PFCMK can be prepared as an antioxidant and antimicrobial for natural pharmaceutical, cosmetic products, and other industrial products.