Oroxylin A

Gushen Antai recipe (GSAT), known herbal medicine, has long been used in China to treat early pregnancy loss. Several randomised controlled trials have demonstrated its efficacy in improving clinical pregnancy rates. This study aimed to elucidate the mechanism of GSAT in patients undergoing in vitro fertilisation-embryo transfer (IVF-ET).

Patients undergoing IVF-ET were recruited on day 14 after embryo transfer. Participants either received GSAT alongside hormonal medication for 2 weeks (intervention group) or received hormonal treatment (control group). Plasma metabolites and inflammatory factors was analysed by gas chromatography-mass spectrometry and enzyme-linked immunosorbent assay, respectively. Faecal microbiota was assessed by 16S rRNA sequencing.

GSAT was found to contain 56.44% flavonoids, primarily come from Scutellariae Radix, including baicalin, baicalein, wogonoside, wogonin, oroxylin A and Chrysin 6-C-glucoside 8-C-arabinoside. At the end of the fourth week after embryo transfer, plasma levels of interleukin (IL)-2 and tumour necrosis factor-α were significantly lower in the intervention group than in the control group, whereas the anti-inflammatory cytokine IL-10 were markedly higher (687.3 vs. 448.5 pg/mL, p < 0.01). Moreover, the plasma IL-10 levels and proportion of four kinds of fatty acids (lauric acid, myristic acid, palmitic acid, linoleic acid) in plasma correlated with each other. These fatty acids were not directly detected in GSAT and may originate from biosynthesis by gut microbiota.

The alteration of plasma cytokine levels (IL-10, TNF-α and IL-2) associated with GSAT intervention was linked to specific fatty acids produced by characteristic intestinal microbiota. These results provide insights into the mechanism underlying the role of the GSAT in improving clinical pregnancy rates.