Assessment of 12 Ginsenosides and the Antioxidant Activity of Red Ginseng Sprout Extracts

This study aimed to establish a high-performance liquid chromatography coupled with photodiode array detection (HPLC–PDA) method for the simultaneous quantification of 12 ginsenosides in red ginseng sprout (RGS) extract produced from smart-farm-cultivated ginseng sprouts and to evaluate its antioxidant activity as part of a quality assessment framework. Twelve representative major and heat-transformed minor ginsenosides were selected to capture the characteristic protopanaxadiol and protopanaxatriol profiles of RGS. Hydroponically cultivated ginseng sprouts were subjected to nine cycles of steaming and drying, followed by pressurized extraction. The total ginsenoside content was 31.54 mg/g, with Re and Rd as the predominant ginsenosides. The extract exhibited a high total phenolic content (7.98 mg gallic acid equivalents per gram) and flavonoid content (4.65 mg rutin equivalents per gram). Antioxidant activity was evaluated using 2,2-diphenyl-1-picrylhydrazyl (DPPH IC50 = 7.88 mg/mL) and 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS IC50 = 24.81 mg/mL) radical scavenging assays. Pearson’s correlation analysis revealed strong positive correlations between ginsenosides (Re, Rg2, Rd, and Rh1), phenolic/flavonoid content, and antioxidant activity (R > 0.84, p < 0.01). This study provides an HPLC–PDA platform that achieves baseline-resolved, simultaneous quantification of 12 ginsenosides in RGS and links this compositional profile to antioxidant markers, supporting the quality control of smart-farm-derived ginseng products.