The traditional Chinese medicine Scrophulariaceae is the dried rhizome of Scrophulariaceae.

The medicinal use of Xuanshen was first published in Shennong Materia Medica Classic, which is slightly cold, sweet, bitter and salty, returning to lung, spleen and kidney, and has the functions of clearing heat and cooling blood, nourishing Yin and reducing fire, and detoxifying and dispersing knots. It is found that xuanshen contains various chemical components such as cyclic ether terpenes and phenylpropanoid, which has pharmacological activities such as protecting cardiovascular and cerebrovascular system, anti-inflammation and enhancing immunity. This paper reviews the study of chemical composition and pharmacological activity of Metshen in recent years.

1 Chemical Composition

The chemical components of Scrophulariae include iridoid, phenylpropanes, terpenes (triterpenes, diterpenes, etc.), phenol, phenylethanolsides, sterols, flavonoids, fatty acids and sugars, among which iridoid and phenylpropanes have been reported more.

1.1 Iridoid

The iridoid terpenoids of Scrophulariformis are water-soluble, including four types, one cyclopentane type: harpagoside and its derivatives. The second cyclopentene type, which is peach phylloside and its derivatives, etc. The third type epoxy-cyclopentane is catalpol and its derivatives. The four classes are variated iridoid.

1.2 Phenylpropyl

Phenylpropionin is another active component of Scrophularia Scrophularia, which is mainly characterized by a,β-unsaturated phenylpropionic acid, glucose, rhamnoose and other phenylpropionin glycosides, with anti-inflammatory, anti-platelet aggregation, liver protection and other activities.

1.3 Terpenoids

The terpenes have the same biosynthesis process in plants. The large amount of iridoid terpenes in Scrophulariae indicates that it has the biological basis of diterpenoids and triterpenoids. The mass fraction of terpenes in volatile components of Scrophulariae is as high as 3.49%.

1.4 Phenol and phenylethanol glycosides

Phenol and phenylethanol glycosides were also isolated from Scrophulariae.

1.5 Other Compounds 

Scrophulariae also contains flavonoids and steroids, organic acids cinnamic acid, 4-hydroxy-3-methoxybenzoic acid, ferulic acid, p-methoxycinnamic acid, succinic acid; 5-hydroxymethylglyoxal; Diterpenoid cryptomerol; Triterpenoid ursolic acid and asparagine, fructose, sucrose, glucose, triterpenoid saponins, flavonoid aglycones, alkaloids and volatile oils, etc.

2 Pharmacological activity

The effects of clearing heat and cooling blood, nourishing Yin and lowering fire, detoxifying and clearing up are closely related to pharmacological activities such as anti-inflammatory and immunomodulatory functions.

2.1  Anti-myocardial ischemia and hypertrophy

The 75% ethanol extract of Scrophulina decreased the average blood pressure of anesthetized cats by 40.5%, and significantly increased the coronary artery flow in isolated rabbits and mice

Myocardial rubidium uptake; Mildly inhibiting heart rate and cardiac contractility, enhancing hypoxia endurance in mice, and having protective effect on acute myocardial ischemia in rabbits. These results indicate that Scrophulariae can reduce oxygen consumption and increase oxygen supply, which is suitable for drug development in cardiovascular diseases.

In the study conducted by Gu Weiliang et al on the effect of water extract of Scrophularia Scrophularia on myocardial fibrosis in rats with ventricular remodeling, it was found that water extract of Scrophularia Scrophularia can reduce the amount of myocardial Hyp in rats, inhibit the hypertrophy of cardiomyocytes, reduce the cross-sectional area of left ventricular cardiomyocytes, and significantly inhibit both myocardial cells and interstitial collagen remodeling, reflecting the characteristics of a good inhibition of ventricular remodeling.

2.2  Anti-cerebral ischemia

Scrophulariae extract can significantly reduce the volume of cerebral infarction and improve nerve function after 24h of cerebral ischemia. It can significantly improve cortical CBF and blood flow after 2h ischemia. The total glycosides of scrophulariae can improve the behavior disorder caused by middle artery ischemia in rats. Reduce the infarct size and decrease the infarct rate of cerebral ischemia rats; The water content of brain tissue was decreased in middle artery embolization model rats, which showed a better protective effect on focal cerebral ischemia.

2.3  Anti-platelet aggregation

Extracts of Scrophulina ether, alcohol and water can significantly inhibit platelet aggregation and reduce the effect of PAI-1 in rats, indicating that Scrophulina extract has a strong effect on anti-platelet aggregation and enhancement of fibrinolytic activity. Phenpropanol XS-8 decreased both TXB and 6-keto-PGF0 in plasma, but increased the value of 6-keto-PGF10/TXB2, indicating that XS-8 reduced TXB₂more significantly, which initially explained the possible cause of anti-platelet aggregation in Scrophulina. In addition, after subcutaneous injection of harpagoside, the content of cAMP in plasma decreased, and the ratio of cAMP/cGMP recovered to the level of normal control group.

2.4  Anti-inflammatory

Scrophularia Scrophularia is often used to treat inflammation such as pharyngitis and tonsillitis. High dose extract of Scrophularia Scrophularia can significantly reduce the concentration of inflammatory factors TNF-c, IL-1β, IL-6, and increase the concentration of anti-inflammatory factor IL-10. The pigment extract of Scrophularia Scrophulariae can inhibit the swelling of ear induced by xylene and the increase of peritoneal capillary permeability induced by acetic acid, especially at high dose. The oral liquid of Scrophulariae can significantly inhibit the swelling of rat foot caused by egg white inflammation, the swelling of mouse ear shell caused by croton oil inflammation and the formation of mouse granuloma.

The anti-inflammatory mechanism study showed that the selective inhibition of TX synthase and angorosideC by angorosideC can inhibit the release of TXB ₂, and both angorosideC and acteoside inhibit the production of arachidonic acid and metabolites leukotriene B and verbascoside, reducing the production of superoxide radicals and thus reducing the activity of iNOS.

2.5 Liver Protection

Acteoside, decaffeoylacteoside, cistanoside F and other phenylpropanes have better liver protection. acteoside could significantly inhibit apoptosis of model hepatocytes, up-regulate the expression of bcl-2 protein and down-regulate the expression of Fas/FasL. The results showed that it could significantly increase the survival rate of injured hepatocytes and decrease LDH level in vitro. In vivo, it can significantly reduce AST and ALT levels in rats with liver failure. In addition, Homoplantaginin flavonoids in the leaves of Scrophulariae also showed hepatoprotective activity.

2.6 Other Activities

Other pharmacological activities of Scrophulariae extract include: immune regulation, anti-bacteria, anti-atherosclerosis, etc. Scrophulariformis scrophulariformis had good antioxidant activity, and 20% ethanol extract had the highest DPPH clearance rate, 100% ethanol extract had the lowest clearance rate. Although the changes of all protein points in endotoxemia could not be completely corrected, most of them could be down-regulated. Oral dose of 200,500 mg~kg-1 can significantly inhibit pruritus induced by substance P; The binding rate of insulin to insulin receptor of human red blood cells could not be affected, suggesting another mechanism of hypoglycemia.

Scrophulariformis is a traditional Chinese medicine commonly used in China, with rich resources and a long history. Its main components contain iridoid and phenylpropanoid glycosides, the pharmacological activities and clinical effects of these components are consistent, can be used as the material basis of the pharmacological effects of Scrophulariae.

With the separation and identification of the chemical components of Scrophularia Scrophularia and the in-depth pharmacological research of the active components, it is expected that new drugs with good efficacy and low toxicity will be developed in the future for better clinical use.