关键词: 铁皮石斛（Dendrobium officinale）, 体外抗氧化活性, 模型, 评价, 自由基清除, 干燥, 贮藏

Abstract: This study employed a multi-model evaluation method to systematically assess the in vitro antioxidant activity of Dendrobium officinale flowers from Yandang Mountain, and to compare the differences in their activity under various drying and storage conditions, thereby providing a theoretical basis for quality control and further development. The contents of total phenols and total flavonoids in differently processed samples were determined. The antioxidant activity was comprehensively evaluated using various in vitro models, including DPPH·,ABTS⁺·,·OH, and O₂^-· radical scavenging capacities, Fe²⁺ chelating ability, and Fe³⁺ reducing antioxidant power (FRAP), with vitamin C and EDTA as positive controls. The IC₅₀ values were calculated. Ultimately, the antioxidant activity of Dendrobium officinale flowers from Yandang Mountain under different drying and storage conditions was evaluated independently using 8 models and comprehensively evaluated through PCA dimensionality reduction. The results showed that Dendrobium officinale flowers from Yandang Mountain were rich in phenolic and flavonoids and exhibited broad-spectrum, concentration-dependent antioxidant activity. They performed particularly well in scavenging ·OH and also possessed certain metal ion chelating and reducing abilities. Different antioxidant indicators showed varying sensitivities to processing conditions, ·OH scavenging ability was the most sensitive, while O₂^-· scavenging ability was less affected by the process. Among drying methods, freeze drying significantly outperformed hot-air drying in most indicators. Regarding storage temperature, -80 ℃ freezing was generally better than -18 ℃ freezing.

Key words: Dendrobium officinale, in vitro antioxidant activity, model, evaluate, free radical scavenging, drying, storage