OBJECTIVE:To investigate the effective ingredients of Danshen (Radix Salviae Miltiorrhizae) and Honghua (Flos Carthami) (Danhong) on protective properties towards neonatal rat hippocampal neurons under hypoxia condition.METHODS:Primary culture of neonatal rat hippocampal neurons was used to model hypoxia damage on the hippocampus.Methyl thiazolyl tetrazolium (MTT) assay and preliminary experiments were conducted to identify the four effective ingredients of Danhong,along with the injection of positive drug onto hippocampal neurons at a non-toxic dosage level.The cultured cells were randomly divided into 12 groups:the normal group,model group,positive drug control group and nine compatibility groups of the four effective ingredients.Different test methods were applied to determine lactate dehydrogenasein (LDH),total superoxide dismutase (T-SOD),malondialdehyde (MDA),6-keto prostaglandin F1a (6-keto-PGF1a),thromboxane B2 (TXB2),mitochondrial membrane potential (MMP),free calcium ions concentration ([Ca2+]i) and early onset cell apoptosis.RESULTS:Different compatibility groups could inhibit the content of LDH and intracellular calcium overload,increase activity in T-SOD,decrease level of MDA and TXB2,improve level of 6-keto-PGF1a and MMP,and prevent the early onset cell apoptosis.CONCLUSION:The compatibility of four effective ingredients of Danhong had protective effect toward hippocampi hypoxia.The mechanism might be related to inhibit oxidative stress damage and cell apoptosis,resist thrombosis,and reduce the intracellular calcium ion of overload.