Comparative effects of tetrandrine and berbamine on guineapig airway microvascular leakage induced by platelet-activating factor and other allergic mediators

The potential of tetrandrine as a protective agent for ischemic stroke

Stroke is one of the leading causes of mortality, with a high incidence of severe morbidity in survivors. The treatment to minimize tissue injury after stroke is still unsatisfactory and it is mandatory to develop effective treatment strategies for stroke. The pathophysiology of ischemic stroke is complex and involves many processes including energy failure, loss of ion homeostasis, increased intracellular calcium level, platelet aggregation, production of reactive oxygen species, disruption of blood brain barrier, and inflammation and leukocyte infiltration, etc. Tetrandrine, a bisbenzylisoquinoline alkaloid, has many pharmacologic effects including anti-inflammatory and cytoprotective effects. In addition, tetrandrine has been found to protect the liver, heart, small bowel and brain from ischemia/reperfusion injury. It is a calcium channel blocker, and can inhibit lipid peroxidation, reduce generation of reactive oxygen species, suppress the production of cytokines and inflammatory mediators, inhibit neutrophil recruitment and platelet aggregation, which are all devastating factors during ischemia/reperfusion injury of the brain. Because tetrandrine can counteract these important pathophysiological processes of ischemic stroke, it has the potential to be a protective agent for ischemic stroke.

Anti-hyperglycemic effect of fangchinoline isolated from Stephania tetrandra Radix in streptozotocin-diabetic mice

Kampo medicine, Stephania tetrandra Radix (Stephania) in Boi-ogi-to increases the blood insulin level and falls the blood glucose level in streptozotocin (STZ)-diabetic ddY mice. These actions of Stephania are potentiated by Astragalus membranaceus Bunge Radix (Astragali) in Boi-ogi-to (Liu et al., J. Traditional Med., 17, 253-260, 2000). In the present study, actions of bis-benzylisoquinoline alkaloids isolated from Stephania were investigated in the hyperglycemia of STZ-diabetic mice. A main bis-benzylisoquinoline alkaloid, fangchinoline (0.3-3 mg/kg) significantly fell the blood glucose level of the diabetic mice in a dose-dependent manner. The effect of fangchinoline was 3.9-fold greater than that of water extract of Stephania. However, another main compound, tetrandrine (1-100 mg/kg) did not have any effect. The water extract of Astragali did not affect singly but potentiated the anti-hyperglycemic action of fangchinoline (0.3 mg/kg). Out of used compounds (1 mg/kg) isolated from Stephania, fangchinoline, fangchinoline 2'-N-alpha-oxide and 2'-N-norfangchinoline, which are substituted with 7-hydroxy side chain for 7-O-methyl side chain, decreased to near 50% of high blood glucose level. In addition, tetrandrine 2'-N-beta-oxide, tetrandrine 2'-N-alpha-oxide, tetrandrine 2-N-beta-oxide, fangchinoline 2'-N-alpha-oxide, which are added to 2- or 2'-N-oxide side chain, also decreased to near 50% of the high blood glucose level. In conclusion, fangchinoline but not tetrandrine from Stephania shows the anti-hyperglycemic action in the STZ-diabetic mice. The demethylation of 7-O-position and/or addition of 2- or 2'-N-oxide side chain in bis-benzylisoquinoline compounds in Stephania have a role for the induction of the anti-hyperglycemic actions.

Potent inhibitory effect of tetrandrine on experimental allergic conjunctivitis in mice

This study investigated the effectiveness of tetrandrine (TDR) on experimental allergic conjunctivitis secondary to ragweed pollen. SWR/J mice were divided as follows: group 1, normal controls; group 2, sensitized but untreated; group 3, sensitized, buffered saline (BS)-treated; and group 4, sensitized, TDR-treated. The last three groups were exposed to ragweed through topical contact on the nasal and conjunctival mucosae followed by challenge with the allergen on the conjunctiva. Groups 3 and 4 received doses of BS and TDR, respectively. The allergic conjunctivitis was evaluated by scoring of the clinical signs and histopathology. mRNA gene expression of interleukin 1 beta (IL-1 beta) and IL-5 in the conjunctiva was analyzed by polymerase chain reaction techniques. All mice exposed to ragweed developed allergic conjunctivitis clinically and histologically. The conjunctivitis was significantly modulated by intraperitoneal injection of a new anti-inflammatory agent, TDR. Histopathologic analysis demonstrated that TDR strikingly reduced the conjunctival eosinophil infiltration and the number of intact and degranulating mast cells. IL-1 beta and Il-5 mRNA gene expression in the conjunctiva of TDR-treated mice was dramatically down-regulated compared with untreated and BS-treated controls. The results indicate that TDR may have potential clinical use in the treatment of conjunctivitis.

Tetrandrine potently inhibits herpes simplex virus type-1-induced keratitis in BALB/c mice

This study investigated the effect of tetrandrine (TDR) on experimental herpes simplex keratitis (HSK) in mice. BALB/c mice were divided as follows: Group 1, untreated; Group 2, acyclovir (ACV)-treated from day 0 postinfection; Group 3, ACV-treated from day 7; Group 4, TDR-treated from day 0; and Group 5, TDR-treated from day 7. All mice were infected in the right cornea with herpes simplex virus (HSV) type I. TDR 30 mg/kg and ACV 120 mg/kg were administered intraperitoneally daily. The mice were observed for 14 days postinfection. Clinical inflammatory reactions and ocular histopathology were analyzed. The herpes specific antibody response and the delayed type hypersensitivity (DTH) response were studied. Of the 22 untreated mice, 16 developed HSK (incidence, 72.7%). TDR given from day 7 reduced the HSK incidence to 8.5% (p < 0.01); the incidence of HSK was 45.4% in mice treated with TDR from day 0 (p > 0.05). Systemic ACV given from day 0 inhibited HSK development (p < 0.01); ACV given from day 7 resulted in an HSK incidence of 50% (p > 0.05). The specific anti-HSV antibody response in the serum of mice treated with TDR or ACV either from day 0 or day 7 was significantly less than that of untreated mice (p < 0.01 and p < 0.05, respectively), and TDR treatment suppressed DTH responses to HSV (p < 0.05). Systemic TDR administered after HSV inoculation of the cornea significantly modulates murine HSK development at least partly by modifying the host immune/inflammatory response to the virus.

Effects of Chinese herbal products on mammalian retinal functions

Ocular ischemia and inflammation are two major factors which induce retinal degeneration. Treatment of these diseases has been difficult, though numerous agents have been tried. Natural products could be a good field to venture into because various medicinal plants have been used for centuries to treat circulation stasis, inflammation, visual disturbances, and eyesight failure. Tetramethyl-pyrazine, coumarin, methyl tyramine, rescinnamine, apocynin, and hesperetin are some natural products isolated from Chinese herbs for improving ocular blood flow, particularly in the choroid and retina. For ocular inflammation, at least a dozen natural products are reviewed in this article. Among those, matrine, tetrandrine and osthole draw particular attention, because they are effective mainly as interleukin-1 blockers, but not as arachidonate blockers. As a result, these agents are potent anti-inflammatory agents and are even more potent than the prototype corticosteroid, prednisolone. It is hoped that all aforementioned agents can be used to treat retinopathies resulting from ocular ischemia and/or ocular inflammation. Scoparone, corylifolinin, epigallocatechin-3-0-gallate, esculetin, and lespedezaflavanone A are some natural products which can improve retinal functions measured with electroretinogram's b-wave recovery. Further research should be carried out to relate natural products which can improve ocular blood flow and inflammation to retinal function and vice versa.

Tetrandrine inhibits breakdown of blood-aqueous barrier induced by endotoxin and interleukin-1 alpha in rats

Tetrandrine was shown to significantly inhibit uveitis induced by endotoxin and interleukin-1 alpha (IL-1 alpha) in rats. The dose-response curve of IL-1 alpha-induced uveitis was inhibited in a non-competitive manner. The maximum inflammation induced by IL-1 alpha was suppressed to 58.4%, 38.3% and 18.3% of the control peak by 5 mg/kg, 10 mg/kg and 20 mg/kg t.i.d. of tetrandrine, respectively. The maximum inflammation induced by endotoxin was suppressed to 56.5% and 38.0% by 5 mg/kg and 10 mg/kg t.i.d. of tetrandrine, respectively. The mechanism of tetrandrine's anti-inflammation could involve numerous pathways of inflammation processes and multiple inflammatory mediators. The results of this study indicate that tetrandrine appears to be a broad spectrum, non-steroidal, novel ocular anti-inflammatory agent.

Anti-inflammatory activity of the isoquinoline alkaloid, tetrandrine, against established adjuvant arthritis in rats

Two isoquinoline plant alkaloids, tetrandrine (1) and berbamine (2), have been evaluated for anti-inflammatory activity in an acute paw oedema assay and in adjuvant-induced arthritis in rats. 1 but not 2 suppressed the chronic inflammation in the arthritis model but neither compound was active in the acute inflammation assay. In the adjuvant-induced polyarthritis, 1 was not effective when given at the time of inoculation (Day 0), nor just before (Day 7-10) signs of arthritis were evident. However, when given on a therapeutic dose schedule (Days 10-13) or continually (Day -1 to +14) on a prophylactic schedule, signs of arthritis including weight loss due to cachexia were significantly reduced. Given orally, 1 was considerably more potent than aspirin but not gastro-irritant and may be a promising lead for the development of a safe and effective treatment of chronic inflammatory diseases.

Effect of berbamine on blood and bone-marrow stem cells of cyclophosphamide-treated mice

The bisbenzylisoquinoline alkaloid berbamine has been used in China and Japan for the therapy of leukopaenic complications of cancer. Mice treated with non-toxic doses showed significant enhancement of neutrophil and lymphocyte counts in the circulation, but a decrease in the numbers of bone marrow stem cells in a dose-dependent manner after two weeks. Similar findings were observed in cyclophosphamide-treated mice. These results indicate that berbamine acts by stimulating the maturation and release of leukocyte progenitors, and may have value in leukopaenic patients.

Synergy between tetrandrine and FK506 in prevention of diabetes in BB rats

Delayed administration of tetrandrine, a novel broad-spectrum anti-inflammatory agent, to BB rats at a dosage schedule of 20 mg kg-1 day-1 from 79 days of age reduced the cumulative incidence of diabetes from 73.1 to 41.7% (p < 0.01). Brief treatment with the potent immunosuppressive agent FK506 at a dosage schedule of 0.5 mg kg-1 day-1 from 79 days of age for 5 days had no significant effect on the cumulative incidence of diabetes (66.7%, p > 0.1). However, the combination of tetrandrine and FK506 in the afore-mentioned dosage schedules reduced the incidence of diabetes to only 3.6% (p < 0.001). These results suggest that the strong synergy between tetrandrine and FK506 may offer a safe and effective therapeutic strategy for the treatment of patients with recent onset or imminent IDDM.