Orostachys species have been recognized as medicinal herbs in East Asia. Although O. fimbriata is known as a traditional medicine, its antioxidant properties have not been investigated compared to other Orostachys species. In this study, we characterized the antioxidant compounds and determined the antioxidant activity of O. fimbriata for the first time. As a result, 1 g of O. fimbriata extracts contains 288.5 ± 7.4 mg polyphenols, which contains 159.7 ± 8.3 mg flavonoids. In particular, 21.6%, 6.6%, and 2.6% of the total flavonoids were identified as epicatechin gallate, quercetin, and kaempferol, respectively, by LC-MS system. The DPPH IC50, ABTS IC50, and FRAP value of the extracts was determined to be 27.6 ± 5.5 μg/mL, 125.7 ± 6.0 μg/mL, and 115.0 ± 4.4 mmol/L, respectively. These activities were 30–57% of the positive control, ascorbic acid. In conclusion, it was demonstrated that O. fimbriata has outstanding antioxidant properties. This study highlights the need for further investigations toward in-depth research on the pharmacological functions of O. fimbriata.

Elderberry, which is well known for its richness in anthocyanin, is attracting attention in the bioindustry as a functional material with high antioxidant capacity. The aim of this study is to optimize extraction conditions to more effectively recover anthocyanins from elderberry. In a fundamental experiment to determine the suitable solvent, various GRAS reagents, such as acetone, ethanol, ethyl acetate, hexane, and isopropyl alcohol, were used, and total phenol and anthocyanin contents were detected as 9.0 mg/g-biomass and 5.1 mg/g-biomass, respectively, only in the extraction using ethanol. Therefore, ethanol was selected as the extraction solvent, and an experimental design was performed to derive a response surface model with temperature, time, and EtOH concentration as the main variables. The optimal conditions for maximal anthocyanin recovery were determined to be 20.0 °C, 15.0 min, and 40.9% ethanol, and the total anthocyanin content was 21.0 mg/g-biomass. In addition, the total phenol and flavonoid contents were detected as 67.4 mg/g-biomass and 43.8 mg/g-biomass, respectively. The very simple and economical extraction conditions suggested in this study contributed to improving the utilization potential of anthocyanin, a useful antioxidant derived from elderberry.

Peanut shells (PSs) generated from agricultural waste contain valuable compounds with bioactive properties such as anti-aging, antimicrobial, and antioxidant properties, making it desirable to recycle them as a sustainable resource. The aim of this study is to design an effective luteolin recovery process as the first step of an integrated biorefinery utilizing PSs as raw material. The major extraction variables and their ranges for luteolin recovery from PSs were determined (0–60 °C, 1–5 h, 0–100% MeOH concentration) and a predictive model was derived through a response surface methodology (RSM). Based on the predictive model, the equation determined for the maximal extraction of luteolin at 1 h was as follows: y = –1.8475x + 159.57, and the significant range of variables was as follows: 33.8 °C ≤ temperature (x) ≤ 48.5 °C and 70.0% ≤ MeOH concentration (y) ≤ 97.5%, respectively. High antioxidant and elastase inhibitory activities of PS extracts were confirmed, and these results support their potential to be used as functional materials. In addition, 39.2% of the solid residue after extraction was carbohydrate, which has potential as a carbon source for fermentation. This study provides a useful direction on an integrated biorefinery approach for sustainable agricultural waste valorization.