Calycosin orchestrates the functions of Danggui Buxue Tang, a Chinese herbal decoction composing of Astragali Radix and Angelica Sinensis Radix: An evaluation by using calycosin-knock out herbal extract

Abstract Ethnopharmacological relevance D anggui B uxue T ang (DBT) is a classical Chinese herbal decoction containing two herbs, A stragali R adix (AR) and A ngelicae S inensis R adix (ASR), which serves as dietary supplement for treating women menopausal syndromes. Pharmacological studies indicate that DBT has estrogenic, erythropoietic and osteogenic properties; however, the action mechanism for this complex herbal decoction is not known. Calycosin, a major flavonoid in AR, shares similar structure with β-estradiol, and thus which is hypothesized to be the critical compound of DBT. Here, we aim to investigate the role of calycosin in DBT in terms of its biological functions by using a calycosin-depleted DBT decoction (DBT Δcal ). The biological functions of DBT Δcal and parental DBT were systematically compared. Materials and methods In order to standardize DBT decoction, four chemical markers were determined and quantified by HPLC. A semi-preparative HPLC method was utilized to prepare DBT Δcal . The authenticity of DBT Δcal was evaluated by LC-QQQ-MS/MS. To reveal the effect of calycosin on DBT functions, several cell assays related to the known properties of DBT were revealed, including estrogenic, erythropoietic and osteogenic functions. Results As compared to parental DBT, the estrogenic, erythropoietic and osteogenic abilities were markedly reduced in DBT Δcal . However, calycosin alone did not show significant responses. Conclusions Our results suggest that calycosin is a bioactive chemical in DBT decoction, and which could play a key linker in orchestrating multi-components of DBT as to achieve maximal functions. These discoveries should be invaluable in drug development and in investigating the modernization of traditional Chinese medicine from a new perspective.