**4. Mechanisms of** *Salvia miltiorrhiza* **in aging-associated CVD and cancer**

#### **4.1 Therapeutic properties of Danshen in aging-associated CVD**

Salvianolic acids, especially SalA and SalB, have potent anti-oxidative capabilities due to their polyphenolic structure. The cardiovascular protection of salvianolic acids include the following mechanisms: ROS scavengers, reduction of leukocyte-endothelial adherence, inhibition of inflammation and metalloproteinases expression from aortic smooth muscle cells, and indirect regulation of immune function, and also competitive binding to target proteins to interrupt protein–protein interactions [77].

SalA inhibits oxidative stress directly by scavenging the free radicals to improve the endothelial dysfunction [78], vascular smooth muscle cell proliferation [79], pulmonary arterial hypertension [80], and cardiac fibrosis. SalA can chelate Cu2+ and inhibit Cu2+-promoted oxidation of low-density lipoprotein to reduce the production of malondialdehyde which is the final product of polyunsaturated fatty acids peroxidation in a cell-free system [81]. Interesting, there is a study showed both Salvianolic acid and tanshinone contribute to the cardioprotective effect of Danshen. Tanshinone mainly inhibits intracellular calcium and cell adhesion pathways at an early stage after ischemic injury whereas Salvianolic acid acts mainly by decreasing apoptosis [82].

#### *Polyphenols of* Salvia miltiorrhiza *in Aging-Associated Cardiovascular Diseases and Cancer DOI: http://dx.doi.org/10.5772/intechopen.98632*

SalB protects human endothelial progenitor cells against oxidative stress-mediated dysfunction by modulating Akt/mTOR/4EBP1, p38 MAPK/ATF2, and ERK1/2 signaling pathways and prevents oxidative-induced endothelial dysfunction via downregulated NADPH oxidase 4 and eNOS expression [18].

Cardiac fibrosis is a chronic harmful result of hypertension which may further advance to heart failure and increased matrix metalloproteinase-9 (MMP-9) contributes to the underlying mechanism. In neonatal cardiac fibroblast, SalA inhibited fibroblast migration, blocked myofibroblast transformation, inhibited secretion of intercellular adhesion molecule (ICAM), interleukin-6 (IL-6) and soluble vascular cell adhesion molecule-1 (sVCAM-1) as well as collagen induced by MMP-9. The inhibition on MMP-9 by SalA was further confirmed in cultured cardiac H9c2 cell overexpressing MMP-9 in vitro and in heart of spontaneously hypertensive rats (SHR) in vivo [83]. SalA targeted transgelin and had a protective effect on myocardium by stabilizing the transgelin-actin complex, modulating the reorganization of the actin cytoskeleton, facilitating F-actin bundling, further enhancing the contractility and blood flows of coronary arteries, and improving outcomes of myocardial ischemia [84]. SalB facilitates angiogenesis and alleviated cardiac fibrosis and cardiac remodeling in diabetic cardiomyopathy by suppressing insulin-like growth factorbinding protein 3 (IGFBP3) [85]. SalB can alleviate Ang II-induced cardiac fibrosis via suppressing the NF-κB pathway in vitro [86]. It is reported that treatment with 5% water-soluble extract of Danshen which contained SalB for 12 weeks lowers blood cholesterol and reduces atherosclerotic plaque formation in diet-induced hypercholesterolemic rabbits, which is associated with its ROS scavenging capacity (**Table 1**) [87].

Homocysteine (Hcy), a by-product of methionine metabolism, may lead to hyperhomocysteinemia which is the risk factors responsible for the development of several vascular diseases (thromboembolism, atherosclerosis, stroke, vascular diseases and dementia). The aqueous extracts of Danshen against vascular atherosclerotic lesions though inhibiting Hcy-induced rat smooth muscle cell line(A10) growth via the PKC/MAPK-dependent pathway, attenuated carbonyl-modification of specific cytoskeleton and chaperone proteins leading to cell type transformation, also, scavenging of ROS and subsequent modulation of protein carbonylation to inhibit cell proliferation [88]. Another study demonstrated the protective effect of Danshen extract against the Hcy-induced adverse effect on human umbilical vein endothelial cell and showed different effectiveness in protection according to the following descending order: Danshen aqueous extract, 3-(3,4-dihydroxy-phenyl)-2-hydroxypropionic acid (Danshensu), protocatechuic acid, catechin and protocatechualdehyde [89]. Danshensu decreases foam cell formation by reducing the expression of TNFα, ICAM-1, and ET-1 while increasing NO production, thus protecting the vascular endothelium from injury [90]. SalA markedly attenuated induction of MKP-3(mitogen-activated protein kinase phosphatases 3) and inhibition of eNOS expression and NO formation under endothelial ischemia/reperfusion condition [91].

Some clinical studies reported that the Danshen preparations in combination with Western medicine were more effective for treatment of various CVDs including angina pectoris, myocardial infarction, hypertension, hyperlipidemia, and pulmonary heart diseases [92]. Our previous series studies showed the most common used single Chinese herbal products which prescribed by TCM Doctors during 2000–2010 in Taiwan is Danshen (16.50% in ischemic stroke; 29.30% in ischemic heart disease; 3.95% in atrill fibrillation; 5.13% in heart failure) [36, 37, 93, 94]*.* There was nearly one-third lower stroke risk in ischemic heart disease patients with combination TCM than patients with non-TCM treatment (95% CI = 0.11–0.84,


↑*: increase;* ↓*: decrease;* ↔*: no change;* ⊝*: inhibit;* ⊕*: promote. cAMP, cyclic adenosine monophosphate; PKA, protein kinase A; CREB, cAMP-response element binding protein; LDL, low-density lipoprotein; MDA, malondialdehyde; MMP-9, Matrix metallopeptidase 9; Akt, protein kinase B; mTOR, mechanistic target of rapamycin; 4EBP1, Eukaryotic translation initiation factor 4E-binding protein 1; p38 MAPK, mitogen-activated protein kinases; ATF2, Activating Transcription Factor 2; ERK1, extracellular signal-regulated kinase 1; Nox4, NADPH oxidase 4; eNOS, Endothelial Nitric Oxide Synthase; ROS, reactive oxygen species; ICAM, intercellular adhesion molecule; IL-6, interleukin-6; sVCAM-1, soluble vascular cell adhesion molecule-1; NF-*κ*B, nuclear factor kappa-light-chain-enhancer of activated B cells; IGFBP3, insulin-like growth factor-binding protein 3.*

#### **Table 1.**

*The main antioxidative mechanisms of* Salvia miltiorrhiza *(Danshen) in CVD.*

P = .02). The higher survival rate (P < .001) and the lower incidence of hemorrhagic stroke (P = .04) in ischemic heart disease patients with TCM treatment was reported [95]. Compared to non-TCM users, the stroke risk was significantly lower in TCM users with atrial fibrillation who were female or younger than 65 years, but not in males, people more than 65 years old, or people with comorbidities [93]. One randomized controlled trial showed *Salvia Miltiorrhiza* Depside Salt combined with aspirin is a clinically effective and safe intervention to treat adults aged 35 and

older with stable angina pectoris without adverse drug reactions such as bleeding tendency occurred [96].

#### **4.2 Therapeutic properties of Danshen in cancer**

SalA and SalB have been reported to owe anti-cancer, anti-inflammatory and cardioprotective activities not only through inducing apoptosis, halting cell cycle and adjourning metastasis by targeting multiple deregulated signaling networks of cancer but also sensitizing cancer cells to chemo-drugs [97].

Acting to protect the organism against these harmful pro-oxidants is a complex system of enzymatic antioxidants (e.g., superoxide dismutase (SOD), glutathione peroxidase, glutathione reductase, catalase) and nonenzymatic antioxidants (e.g., glutathione, vitamins C and D) [98].

SalA elevated ROS levels, downregulated P-glycoprotein, and triggered apoptosis by increasing caspase-3 activity and upregulating Bax expression, while downregulating Bcl-2 expression and disrupting the mitochondrial membrane potential in multidrug resistance MCF-7 human breast cancer cells [99]. In lung cancer, SalA could increase the chemotherapeutic efficacy of cisplatin by enhanced sensitivity to cisplatin in A549/DDP cells mainly through suppression of the c-met/AKT/mTOR signaling pathway [100]. In addition, SalA considerably suppressed the migrative and invasive activity of human NPC cells but not presented cytotoxicity. In SalA-treated NPC cells, the activity and expression of matrix metalloproteinase-2 (MMP-2), a key regulator of cancer cell invasion, were reduced. Additionally, the presence of high concentrations of SalA dramatically abolished the activation of focal adhesion kinase (FAK) and moderately inhibited the phosphorylation of Src and ERK in NPC cells [101].

The anti-tumor effect of SalB is via inhibiting the expression of glucosylceramide and GM3 synthases, and then increases the ceramide accumulation and ceramidemediated Triple-negative breast cancer cell apoptosis [102]. One study indicated SalB induced cell death and triggered autophagy in HCT116 and HT29 cells in a dose-dependent manner, and it is as a novel autophagy inducer in colorectal cancer cells through the suppression of AKT/mTOR pathway [103]. Besides, SalB reduced the cytotoxicity of doxorubicin through scavenging ROS generated by doxorubicin in HepG2 cells and enhance the expression of SOD and decrease that of NADPH oxidase, which resulted in the elimination of ROS [104]. Sal-B regulated proliferation, epithelial-mesenchymal transition (EMT) and apoptosis to reduce the resistance to cisplatin via AKT/mTOR pathway in cisplatin-resistant gastric cancer cells [105].

Rosmarinic acid (RA) inhibited non-small cell lung cancer (NSCLC) by inducing G1 phase cell cycle arrest, apoptosis and the sensitivity of cisplatin-resistant cell via activating MAPK, enhancing p21 and p53 expression, and inhibiting the expression of P-gp and MDR1 [106]. RA reverses cisplatin resistance of NSCLS by activating the MAPK signaling pathway.

Most of the currently available chemotherapeutic and radiotherapeutic agents kill cancer cells by increasing ROS stress. Thus, both ROS-elevating and ROS-eliminating strategies have been developed for cancer therapy. As we know either chemotherapy or radiotherapy was usually associate with uncomfortable side-effects which are burdens to clinical physicians. Our previous researches find the aqueous extract of Danshen has shown anticancer as well as antioxidant effects, besides, it could prevent or mitigate the causative cardiomyopathy through controlling multiple targets without compromising the efficacy of chemotherapy (**Table 2**) [108, 109].


↑*: increase;* ↓*: decrease;* ↔*: no change;* ⊝*: inhibit;* ⊕*: promote. ROS, reactive oxygen species; DDP, cisplatin; AKT, protein kinase B; mTOR, mechanistic target of rapamycin; Bcl-2, B-cell lymphoma 2; Bax, Bcl-2-associated X protein; FAK, focal Adhesion Kinase; ERK, extracellular signal regulated kinase; COX-2/PGE-2; SOD; NADPH.*

#### **Table 2.**

*The therapeutic effect mechanism of polyphenols of Salvia miltiorrhiza (Danshen) in common cancers.*
