Complement modulatory activity of bisbenzylisoquinoline alkaloids isolated from Isopyrum thalictroides--I. Influence on classical pathway in human serum

Properdin deficiency in murine models of nonseptic shock

Hereditary properdin deficiency is linked to susceptibility to meningococcal disease (Neisseria meningitidis serotypes Y and W-135) with high mortality. Its relative contribution toward the outcome of nonseptic shock has not been investigated. Using properdin-deficient C57BL/6 mice and their littermates, this study examines their survival of zymosan-induced and LPS-induced shock. Properdin-deficient mice were more resistant to zymosan shock compared with wild-type mice, which showed greater impairment of end-organ function 24 h after zymosan injection, higher TNF-alpha production by alveolar and peritoneal macrophages, higher TNF-alpha, and, inversely, lower IL-10 levels in peritoneal lavage and circulation and higher plasma C5a levels. Properdin-deficient mice showed significantly higher mortality in LPS shock, elevated TNF-alpha, and, inversely, reduced IL-10 production by peritoneal macrophages as well as lower plasma C5a levels compared with wild-type littermates. NO production by peritoneal macrophages and plasma alpha1-antitrypsin levels at 24 h after the injection of LPS or zymosan were decreased in properdin-deficient mice in both models, and fewer histopathologic changes in liver were observed in properdin-deficient animals. This study provides evidence that properdin deficiency attenuates zymosan-induced shock and exacerbates LPS-induced shock.

In vitro activity of Triclisia patens and some bisbenzylisoquinoline alkaloids against Leishmania donovani and Trypanosoma brucei brucei

In the search for antiprotozoal compounds from natural sources, Triclisia patens displayed activity against L. donovani promastigotes (IC(50) = 1.5 microg/mL) and T. b. brucei blood stream trypomastigote forms (IC(50) = 31.25 microg/mL). In addition, a total of 20 bisbenzylisoquinoline alkaloids were screened for antileishmanial and antitrypanosomal activity in vitro. Fangchinoline (IC(50) = 0.39 microM) was found to be as active as the standard pentamidine against Leishmania donovani promastigotes. Phaeanthine was three-fold more active (IC(50) = 2.41 microM; 1.5 microg/mL) than the standard drug Pentostam against L. donovani amastigotes, but at this concentration was toxic to murine macrophages. In contrast, cocsoline (IC(50) = 12.3 microM; 6.76 microg/mL) was as active as Pentostam, and was not toxic to macrophages at this concentration. Thalisopidine showed the strongest activity (IC(50) = 1.14 microM) against Trypanosoma brucei brucei blood stream form trypomastigotes, but was less active than pentamidine.

Protective effect of fangchinoline on cyanide-induced neurotoxicity in cultured rat cerebellar granule cells

The present study was performed to examine the effect of fangchinoline, a bis- benzylisoquinoline alkaloid, which exhibits the characteristics of a Ca2+ channel blocker, on cyanide-induced neurotoxicity using cultured rat cerebellar granule neurons. NaCN produced a concentration-dependent reduction of cell viability, which was blocked by MK-801, an N-methyl-D-aspartate (NMDA) receptor antagonist, verapamil, L-type Ca2+ channel blocker, and L-NAME, a nitric oxide synthase inhibitor. Pretreatment with fangchinoline over a concentration range of 0.1 to 10 microM significantly decreased the NaCN-induced neuronal cell death, glutamate release into medium, and elevation of [Ca2+]i and oxidants generation. These results suggest that fangchinoline may mitigate the harmful effects of cyanide-induced neuronal cell death by interfering with [Ca2+]i influx, due to its function as a Ca2+ channel blocker, and then by inhibiting glutamate release and oxidants generation.

Complement modulating activity of Rwandan medicinal plants

Forty-two ethanolic extracts of thirty-six Rwandan medicinal plants were investigated for their influence on complement-mediated hemolysis. The plants were selected on the base of their ethnomedicinal use in infections and autoimmune diseases. Eight plant extracts showed an inhibitory activity against the classical pathway of the complement system and ten plant extracts against the alternative pathway. Three plant extracts exhibited an interesting activity against both pathways, i.e. Aspilia pluriseta, Coleus kilimandschari, and Macaranga kilimandscharica (leaves and stem). Further study indicated that the complement inhibitory activity was not caused by chelation of bivalent cations or by direct action on the target erythrocytes.

Inhibitory effect of fangchinoline on excitatory amino acids-induced neurotoxicity in cultured rat cerebellar granule cells

Glutamate receptors-mediated excitotoxicity is believed to play a role in the pathophysiology of neurodegenerative diseases. The present study was performed to evaluate the inhibitory effect of fangchinoline, a bis-benzylisoquinoline alkaloid, which has a characteristic as a Ca2+ channel blocker, on excitatory amino acids (EAAs)-induced neurotoxicity in cultured rat cerebellar granule neuron. Fangchinoline (1 and 5 microM) inhibited glutamate (1 mM), N-methyl-D-aspartate (NMDA; 1 mM) and kainate (100 microM)-induced neuronal cell death which was measured by trypan blue exclusion test. Fangchinoline (1 and 5 microM) inhibited glutamate release into medium induced by NMDA (1 mM) and kainate (100 microM), which was measured by HPLC. And fangchinoline (5 microM) inhibited glutamate (1 mM)-induced elevation of intracellular calcium concentration. These results suggest that inhibition of Ca2+ influx by fangchinoline may contribute to the beneficial effects on neurodegenerative effect of glutamate in pathophysiological conditions.

Complement-mediated antiinflammatory effect of bisbenzylisoquinoline alkaloid fangchinoline

Complement-mediated mode of action of bisbenzylisoquinoline alkaloid fangchinoline was investigated in vivo and in vitro. The application of fangchinoline intraperitoneally (i.p.) to complement normal mice, strain ICR, inhibited the complement activity in serum and peritoneal exudate. The substance activated serum complement of C5-deficient DBA/2 mice. Fangchinoline was able to provoke local inflammatory reaction in both strains after subcutaneous (s.c.) injection. The alkaloid suppressed paw swelling induced by live Candida albicans in ICR and DBA/2 mice. Its effect depended on the dose and time of injection prior to inflammatory reaction. The in vitro experiments proved the interference of fangchinoline action with post-C5 reactions. The substance augmented C5-convertase formation and functional activity. These results are in correspondence with our previous investigations, proving the complement-mediated action of fangchinoline. The antiinflammatory effect could be a consequence of the caused complement exhaustion.

Complement modulatory activity of bisbenzylisoquinoline alkaloids isolated from Isopyrum thalictroides--II. Influence on C3-9 reactions in vitro and antiinflammatory effect in vivo

The main alkaloids isopyruthaline (It1), fangchinoline (It2) and isothalictrine (It3), isolated from Isopyrum thalictroides (L.) were investigated in complement-mediated reactions. The alkaloids influenced the alternative pathway (AP) activity in normal human serum (NHS). They enhanced the inhibitory action of complement activators--carrageenan (Car), zymosan (Zy), hydrogen peroxide (HP) and high temperature via classical pathway (CP) in NHS. Substances strongly potentiated the action of zymosan and cobra venom (CV) in guinea pig serum (GPS). It was established that they could provoke C3 conversion in NHS and mouse sera (MS). The antiinflammatory properties of the alkaloids were evaluated in mouse paw oedema induced by CV, Zy and histamine (His). Isopyruthaline and isothalictrine suppressed paw swelling in CV- and Zy-oedema. They were applied in Zy-induced multiple organ dysfunction syndrome (MODS) in mice. The alkaloids inhibited the increase of the serum complement activity provoked by the injection of zymosan. Itl lowered the mortality rate of mice with MODS if its application proceeded Zy. An increase of the number of mice without tissue injury was established after treatment with It1 and It3.