Table 2.

Active compounds in Bupleurum chinense DC-Paeonia lactiflora Pall herb pair regulate the HPA axis.

Compound	Model	Animal species	Dosage	Behaviour involved	Mechanism of action/main indicators	References
Saikosaponin A	CUMS	Female Wistar rat	25, 50, 100 mg/kg	SPT, FST, and NSFT	Hypothalamus CRH mRNA, CRH protein↓, hippocampal proinflammatory cytokine↓, and CORT↓	[42]
Saikosaponin D	CUMS	Male SD rat	0.75, 1.5 mg/kg	SPT, OFT, and FST	CORT↓, GR↑, weight ↑, p-CREB↑, BDNF↑, and promoting the generation of hippocampal neurons	[43]
Quercetin	Adriamycin	Male Wistar rat	60 mg/kg	FST, OFT, and EPM	CORT↓, relieving brain oxidative stress damage, and regulating immune function	[44]
Ferulic acid	Pentylenetetrazole kindling epilepsy	Male Swiss albino mice	40, 80 mg/kg	TST, SPT	CORT↓, TNF-α↓, and IL-1β↓	[45]
	PS	Female, male SD rats	12.5, 25, 50 mg/kg	SPT, OFT, and FST	Serum ACTH↓, CORT↓, hippocampus GR↑, inhibiting hippocampal inflammation, and improving neuronal damage in hippocampal CA3 area	[46]
Paeoniflorin	PS	Female, male SD rats	15, 30, 60 mg/kg	SPT, FST, and OFT	Serum CRH, ACTH, CORT↓, and relieving neuronal damage in hippocampal CA3 area	[47]
	FST	Male SD rat	10 mg/kg	FST and OFT	Promote gastrointestinal motility, plasma motilin↑, CRH↓, ACTH↓, CORT↓, BDNF↓, norepinephrine↑, and oxidative stress↓	[48]
	CUMS	SD female rats	45 mg/kg	OFT and SPT	HPA axis activity↓, brain 5-HT2AR↓, and brain 5-HT1AR↑	[49]
Protocatechuic acid	ARS	Male, female, Swiss albino mice	100, 200 mg/kg	FST and OFT	Serum CORT↓ and hippocampal oxidative stress↓,	[50]

Note: CUMS: chronic unpredictable mild stress; PS: Prenatal stress; FST: forced swimming test; ARS: Acute restraint stress; SPT: sucrose preference test; NSFT: novelty suppressed feeding test; OFT: open field test; EPM: Elevated Plus Maze; CRH: corticotropin-releasing hormone; GR: Glucocorticoid Receptor; BDNF: brain-derived neurotrophic factor; ACTH: adrenocorticotropic hormone; HPA: hypothalamic-pituitary-adrenal; 5-HT: serotonin; MDA: malondialdehyde; CORT: cortisol.