Comparative Phytochemical Profiling and In Vitro Antioxidant Activity of Extracts from Raw Materials, Tissue-Cultured Plants, and Callus of Oroxylum indicum (L.) Vent.

Extracts from raw materials from different plant parts, tissue-cultured plants, and callus cultures of Oroxylum indicum were analyzed for in vitro antioxidant activities determined by DPPH radical scavenging assay and evaluated for phytochemical profiles by TLC and LC-MS methods. The results were analyzed by principal component analysis (PCA) to evaluate the similarity. Stalk, pedicel, flower, seed, and whole fruit and callus extracts promoted strong antioxidant activity with high total phenolic and total flavonoid contents. The main phytochemicals found in extracts were baicalin, baicalein, and chrysin. Baicalein and baicalin promoted strong antioxidant effects and existed in most extracts while chrysin, which promoted very low antioxidant activity, was a major flavonoid in the leaves and tissue-cultured plants. From PCA analysis by total phenolic and total flavonoid contents, four main clusters including callus and tissue-cultured plant groups from different growth stages, flower group, and whole fruit and leaf group could be organized. When the results were analyzed by PCA using antioxidant activity with total phenolic or total flavonoid contents, all O. indicum samples could be grouped together except the extracts from the root of tissue-cultured plants which separated from the rest due to their low phytochemical contents and weak antioxidant activities.