Cortex Mori Radicis extract promotes neurite outgrowth in diabetic rats by activating PI3K/AKT signaling and inhibiting Ca2+ influx associated with the upregulation of transient receptor potential canonical channel 1.

Cortex Mori Radicis extract (CMR) has various pharmacological properties, such as anti­inflammatory, anti­allergic and anti­hyperglycemic effects. However, the effects and mechanisms of CMR in the neuroregeneration of diabetic peripheral neuropathy (DPN) are unclear. In the present study, the effects of CMR on neurite outgrowth of dorsal root ganglia (DRG) neurons in diabetic rats were investigated and its underlying mechanisms were explored. SD rats were subjected to a high­fat diet with low­dose streptozotocin to induce a Type II diabetes model with peripheral neuropathy. CMR was then applied for four weeks continuously with or without injection of small interfere (si)RNA targeting the transient receptor potential canonical channel 1 (TRPC1) via the tail vein. Blood glucose levels, the number of Nissl bodies, neurite outgrowth and growth cone turning in DRG neurons were evaluated. The expression of TRPC1 protein, Ca2+ influx and activation of the PI3K/AKT signaling pathway were also investigated. The results of the present study showed that CMR significantly lowered blood glucose levels, reversed the loss of Nissl bodies, induced neurite outgrowth and restored the response of the growth cone of DRG neurons in diabetic rats. CMR exerted neurite outgrowth­promoting effects by increasing TRPC1 expression, reducing Ca2+ influx and enhancing AKT phosphorylation. siRNA targeting TRPC1 in the CMR group abrogated its anti­diabetic and neuroregenerative effects, suggesting the involvement of TRPC1 in the biological effects of CMR on DPN.

Natural constituents from Cortex Mori Radicis as new pancreatic lipase inhibitors.

Pancreatic lipase (PL), a key enzyme responsible for the hydrolysis of triacylglycerides in the gastrointestinal tract, has been identified as the therapeutic target for the regulation of lipid absorption. In the present study, six major constituents from a famous Chinese herbal medicine Cortex Mori Radicis (also named sangbaipi in Chinese), have been collected and their inhibitory effects on PL have been carefully investigated and well characterized by a fluorescence-based assay. The results clearly demonstrated that all tested bioactive constituents from Cortex Mori Radicis including sanggenone C (SC), sanggenone D (SD), kuwanon C (KC), kuwanon G (KG), morin and morusin displayed strong to moderate inhibitory effects towards PL with the IC50 values ranging from 0.77 µM to 20.56 µM. Further investigations on inhibition kinetics demonstrated that SC, SD, KC and KG functioned as potent and mixed inhibitors against PL-mediated 4-MU oleate hydrolysis, with the Ki values less than 5.0 µM. Furthermore, molecular docking simulations demonstrated that SD (the most potent PL inhibitor from Cortex Mori Radicis) could create strong interaction with Ser152 (the key amino acid in the catalytic triad) of PL via hydrogen bonding. All these findings provided a new powerful evidence for explaining the hypolipidemic effect of Cortex Mori Radicis, also suggested that some abundant natural compounds in this herbal medicine could be served as lead compounds for the development of new PL inhibitors.

A Tri-O-Bridged Diels-Alder Adduct from Cortex Mori Radicis.

Sanggenon X, an unusual tri-O-bridged Diels-Alder adduct, was isolated from Cortex Mori Radicis. Its structure was established by spectroscopic analysis, including NMR and HR-MS (High Resolution Mass Spectrometry). Sanggenon X contained three O-bridged rings, where the oxygenated bridgeheads were all quaternary carbons. Chemical methylation was carried out to deduce the linkages of the three O-bridges. The absolute configuration was determined by calculating the ECD (Electronic Circular Dichroism) using the TDDFT (Time-Dependent Density Functional Theory) method. Sanggenon X showed significant antioxidant activity against Fe2+-Cys-induced lipid peroxidation in rat liver microsomes, and was as effective as the positive control, curcumin.

Cortex Mori Radicis extract attenuates myocardial damages in diabetic rats by regulating ERS.

Diabetic cardiomyopathy (DCM) is diagnosed when patients with diabetes develop ventricular dysfunction but do not exhibit coronary atherosclerosis or hypertension. Cortex Mori (CM) Radicis,he epidermis of the root of Morus alba L, has been traditionally used for cough treatment in oriental medicine. In this study, we investigated the protection of myocardium by CM in streptozotocin (STZ)-induced diabetic rats and the underlying mechanisms. Diabetes was induced in rats by an injection of STZ at 25mg/kg. The animals were randomly divided into 4 groups: control, diabetes, diabetes with CM treatment, diabetes with CM preventative treatment. Pathological changes were examined by hematoxylin-eosin staining. Extracellular matrix content was assessed by Masson's trichrome staining and Western blot. Endoplasmic reticulum (ER) stress-associated molecules and main components of the mitogen-activated protein kinase (MAPK) pathway were also measured by Western blot. Myocardial damages were induced by the injection of STZ as evidenced by abnormal blood glucose and pathological cardiac changes. Administration of CM markedly ameliorated myocardial damages such as cardiac hypertrophy and fibrosis. ER stress was down-regulated, and p38 and ERK were suppressed by CM. Thus, CM may have therapeutic potential in the treatment of DCM by attenuating ER stress and ERK and p38 MAPK activation.

Bioactive Benzofuran Derivatives from Cortex Mori Radicis, and Their Neuroprotective and Analgesic Activities Mediated by mGluR1.

Four new benzofuran-type stilbene glycosides and 14 known compounds including 8 benzofuran-type stilbenes and 6 flavonoids were isolated from the traditional Chinese medicine, Cortex Mori Radicis. The new compounds were identified as (9R)-moracin P 3'-O-α-l-arabinopyranoside (1), (9R)-moracin P 9-O-ß-d-glucopyranoside (2), (9R)-moracin P 3'-O-ß-d-glucopyranoside (3), and (9R)-moracin O 10-O-ß-d-glucopyranoside (4) based on the spectroscopic interpretation and chemical analysis. Three benzofuran-type stilbenes, moracin O (5), R (7), and P (8) showed significant neuroprotective activity against glutamate-induced cell death in SK-N-SH cells. In addition, moracin O (5) and P (8) also demonstrated a remarkable inhibition of the acetic acid-induced pain. The molecular docking with metabotropic glutamate receptor 1 (mGluR1) results indicated that these neuroprotective benzofuran-type stilbenes might be the active analgesic components of the genus Morus, and acted by mediating the mGluR1 pathway.

Cortex Mori Radicis Extract induces neurite outgrowth in PC12 cells activating ERK signaling pathway via inhibiting Ca(2+) influx.

Cortex Mori Radicis is a traditional Chinese herbal medicine which has a long history of use for the treatment of headaches, cough, edema and diabetes. However, its function and mode of action within nervous system remain largely unclear. In the present study, we have attempted to determine the effects of Cortex Mori Radicis Extract (CMRE) on neuronal differentiation. Here, we reported that CMRE induces the neurite outgrowth in pheochromocytoma PC12 cells and primary cortical neuron. Following the generation of neurite outgrowth, extracellular Ca(2+) influx was inhibited and intracellular Ca(2+) decreased. In addition, CMRE induced the extracellular signal-regulated kinase 1/2 (ERK1/2) activation and also stimulated the Rap1-GTP expression, which is closely linked to neuritogenesis. Moreover, the neurite outgrowth induced by CMRE was antagonized to a marked degree by suppressing activation of p-ERK1/2 with the specific ERK1/2 inhibitor (PD98059), suggesting the involvement of Rap1-GTP and ERK1/2 in CMRE-induced neurite outgrowth. Taken together, these results demonstrate that CMRE induces neurite outgrowth of PC12 cells through Rap1-ERK signaling pathway via inhibiting Ca(2+) influx, and provide a novel insight into the manner in which CMRE participates in neuritogenesis.

Influence of Processing Method on Chemical Composition of Cortex Mori radicis

Cortex Mori radicis (CMR) is a traditional medicine using in the treatment of cough due to heat phlegm. The material consists of Cortex Mori radicis harvesting from the mulberry of four, five, seven and ten years in Hai Duong, Lao Cai, Lam Dong province and bought in Lan Ong street (Ha Noi) and pure honey. CMR is processed by mixing with honey and roasted. CMR with before and after processing also consist of uniform chemical components: flavonoids, tanin, total nitrogen reduced sugars, amino acids and organic acids of the remedy. The contents of flavonoid and tanin in raw CMR and processing CMR does not alter significantly.