Wen-Fei Chiou

Andrographolide prevents oxygen radical production by human neutrophils: possible mechanism(s) involved in its anti-inflammatory effect.

We have reported that andrographolide (ANDRO), an active component of Andrographis paniculata, inhibits inflammatory responses by rat neutrophils. To further elucidate the possible mechanism(s) underlying the ANDROs effect, N‐formyl‐methionyl‐leucyl‐phenylalanine (fMLP)‐induced adhesion and transmigration of isolated peripheral human neutrophils were studied. Pretreatment with ANDRO (0.1–10 μM) concentration‐dependently prevented fMLP‐induced neutrophil adhesion and transmigration. We further examined the up‐expression of surface Mac‐1 (CD11b/CD18), an essential integrin mediated in neutrophil adhesion and transmigration. ANDRO pretreatment significantly decreased fMLP‐induced up‐expression of both CD11b and CD18. Accumulation of reactive oxygen species (ROS) as well as quick intracellular calcium ([Ca++]i) mobilization induced by fMLP displays two important signalling pathways in regulating the up‐expression of Mac‐1 by neutrophils. That ANDRO pretreatment diminished fMLP‐induced production of H2O2 and O2.−, but failed to block that of [Ca++]i mobilization suggested that the ROS but not [Ca++]i signalling could be modulated by ANDRO. To clarify whether ROS production impeded by ANDRO could be an antagonism of fMLP binding, phorbol‐12‐myristate‐13‐acetate (PMA), a direct protein kinase C (PKC) activator, was introduced to activate ROS production. PMA triggered remarkable ROS production and adhesion, and were partially reversed by ANDRO. This indicated that a PKC‐dependent mechanism might be interfered by ANDRO. We conclude that the prevention of ROS production through, at least in part, modulation of PKC‐dependent pathway could confer ANDRO the ability to down‐regulate Mac‐1 up‐expression that is essential for neutrophil adhesion and transmigration.

Mechanisms in mediating the anti-inflammatory effects of baicalin and baicalein in human leukocytes.

To evaluate the possible mechanisms responsible for the anti-inflammatory effects of baicalin or baicalein, phorbol-12-myristate-13-acetate (PMA)- or N-formyl-methionyl-leucyl-phenylalanine (fMLP)-activated inflammatory responses of peripheral human leukocytes were studied. Both baicalin and baicalein diminished fMLP- or PMA-induced reactive oxygen intermediates production in neutrophils or monocytes. Neither baicalin nor baicalein prevented the protein kinase C (PKC)-dependent assembly of the NADPH oxidase. Conversely, myeloperoxidase (MPO) activity was inhibited by baicalin or baicalein. fMLP-induced activation of leukocytes, as reflected by increased surface expression of Mac-1 (CD11b/CD18) and Mac-1-dependent neutrophil adhesion, were also inhibited by baicalin or baicalein. Furthermore, baicalein, but not baicalin, impeded fMLP- or AlF(4)(-)-induced Ca(2+) influx. We conclude that impairment of reactive oxygen intermediates production, through scavenging reactive oxygen intermediates by baicalin, or antagonizing ligand-initiated Ca(2+) influx by baicalein, accounts for the inhibition of Mac-1-dependent leukocyte adhesion that confers the anti-inflammatory activity of baicalin or baicalein.

Protein constituent contributes to the hypotensive and vasorelaxant acttvtties of cordyceps sinensis

Cordyceps sinensis is a herb medicine in China for the treatment of general debility after sickness and for persons of advanced age. In the present study, cordyceps sinensis was extract by phosphate buffer saline (PBS) and dialyzed overnight against PBS using a membrane cut off at 3,500 dalton molecular weight. The resulting macromolecule fraction (defined as CS) was assayed in anesthetized rats for hypotensive effects and in isolated aorta for vasorelaxant effects. Intravenous injection of CS (8,16, 24 and 32 mg/kg, respectively) suppressed significantly the mean arterial pressure (MAP) in a dose-dependent manner. 32 mg/kg of CS induces the maximal hypotensive response with a 58 +/- 4 mm Hg (from 107 +/- 6 to 49 +/- 3 mm Hg) change in MAP and a over 45 min action duration. In aortic rings precontracted with phenylephrine treatment with CS between 0.5 and 500 microg/ml induced dose dependent relaxation. Maximal vasorelaxant response evoked by 150 microg/ml CS was 68.9 +/- 7.3%. Furthermore, CS-induced vasorelaxation is mediated by the endothelium possibly by stimulating the release of the nitric oxide and endothelium-derived hyperpolarizing factor. In conclusion, the present study revealed that presence of a constituent in CS which reduces MAP by relaxing the vascular beds directly. However, the effect may be caused by a single active ingredient or by the combined action of many active agents found in the extract.

The vasorelaxant effect of evodiamine in rat isolated mesenteric arteries: mode of action

The roles of the endothelium, Ca2+ and K+ fluxes in the evodiamine-induced attenuation of vascular contractile responses to vasoactive agents were examined. The results showed that: (1) in rat mesenteric artery rings, evodiamine elicited a concentration-dependent attenuation in the contractile response generated by phenylephrine. The inhibitory potency was greater for intact than for endothelium-denuded preparations. Thus, the vasodilator action of evodiamine appeared to be partially endothelium-interactive (dependent). (2) Evodiamine pretreatment had a greater inhibitory effect on the phenylephrine-induced tonic contraction (via Ca2+ influx) than on the phasic contraction (via Ca2+ release). In addition, evodiamine was more potent to inhibit the restoration by CaCl2 of contractile responses to phenylephrine than a potassium depolarizing solution in media that had been kept calcium-free. These results suggest that block of the Ca2+ influx through receptor-mediated Ca2+ channels may be the major mechanism underlying the vasodilator effect of evodiamine. (3) A K+ channel blocker, tetraethylammonium, almost completely abolished the vasodilatation induced by minoxidil (a known K+ channel opener) but not evodiamine. The possible involvement of K+ channel activation of the vasodilator effect produced by evodiamine was therefore excluded.

Comparative study of the vasodilatory effects of three quinazoline alkaloids isolated from Evodia rutaecarpa.

The vasoreactivity of dehydroevodiamine (1), evodiamine (2), and rutaecarpine (3), quinazoline alkaloids isolated from Evodia rutaecarpa, to aorta smooth muscle demonstrated that they produce a vasodilatory effect on endothelium-intact rat aorta with equal potency. Compound 3 produced a full (100%) nitric oxide-dependent vasodilatation, whereas 2 and 1 produced a partially endothelium-dependent effect, 50% and 10%, respectively. At the same time, I and 2 may also act by other mechanisms, including probably an alpha1-adrenoceptor blocking action and a 5-HT antagonizing action, respectively.

Ligustilide prevents LPS-induced iNOS expression in RAW 264.7 macrophages by preventing ROS production and down-regulating the MAPK, NF-κB and AP-1 signaling pathways.

Angelica sinensis (AS), an herb used in traditional Chinese medicine, is thought to have anti-inflammatory activities. Ligustilide is its most abundant ingredient. This study sought to determine ligustilides effects on lipopolysaccharide (LPS)-induced inflammation in RAW 264.7 macrophages. Ligustilide significantly suppressed the production of nitric oxide (NO), prostaglandin E(2) (PGE(2)) and tumor necrosis factor-α (TNF-α). The inhibition of NO was concomitant with a decrease in the protein and mRNA levels of LPS-induced nitric oxide synthase (iNOS). Furthermore, activation of activator protein-1 (AP-1) and nuclear factor κB (NF-κB) in the nucleus and the cytosolic degradation of IκBα were abrogated by ligustilide. Ligustilide also inhibited the phosphorylation of IκB kinase (IKK) and mitogen-activated protein kinases (MAPKs), including p38 MAPK, extracellular signal-regulated kinase (ERK1/2) and c-Jun N-terminal kinase (JNK). The intracellular reactive oxygen species (iROS) level was also significantly decreased. These results suggest that ligustilide exhibits anti-inflammatory activities by blocking the activation of MAPKs/IKK and the downstream transcription factors AP-1 and NF-κB, which may result from ligustilides down-regulation of iROS production.

Design, synthesis, and biological evaluation of Mannich bases of heterocyclic chalcone analogs as cytotoxic agents

The chalcone skeleton (1,3-diphenyl-2-propen-1-one) is a unique template that is associated with various biological activities. We synthesized Mannich bases of heterocyclic chalcones (9-47) using a one-step Claisen-Schmidt condensation of heterocyclic aldehydes with Mannich bases of acetophenones, and tested the target compounds for cytotoxicity against three human cancer cell lines (prostate, PC-3; breast, MCF-7; nasopharynx, KB) and a multi-drug resistant subline (KB-VIN). Out of the 39 chalcones synthesized, 31 compounds showed potent activity against at least one cell line with IC(50) values ranging from 0.03 to 3.80 microg/mL. Structure-activity relationships (SAR) are also discussed.

EFFECT OF THE PLANT-EXTRACT OSTHOLE ON THE RELAXATION OF RABBIT CORPUS CAVERNOSUM TISSUE IN VITRO

PURPOSE We investigated the cavernosal relaxant effect of osthole, a coumarin isolated from Cnidium monnier (L.) Cusson which has been long used in China as a herbal medicine to improve male sexual dysfunction. MATERIALS AND METHODS Strips of rabbit corpus cavernosum were precontracted with phenylephrine. Corporal relaxation evoked by osthole was then determined in the absence and presence of nitric oxide synthase inhibitor (L-NAME), soluble guanylate cyclase inhibitor (ODQ), cyclooxygenase inhibitor (indomethacin), tetradotoxin, and after endothelium deprivation. RESULTS Corpus cavernosal strips showed relaxation in response to osthole (0.1 approximately 30 microM) in a dose-dependent manner. These effects were reduced partially but significantly by pretreatment with L-NAME, ODQ and by endothelial disruption. However, they were not affected by indomethacin and tetradotoxin treatment. Osthole pretreatment (from 1 to 30 microM) enhanced the sodium nitroprusside (0.3 microM)-induced relaxation of corpus cavernosum in a dose-dependent manner to a maximum of 3 times the pretreatment level at 30 microM osthole. However, this effect was abolished in the presence of zaprinast. Additionally, a higher concentration of osthole (30 microM) also enhanced forskolin-induced relaxation. CONCLUSION The data suggested that osthole possesses a relaxant effect on rabbit corpus cavernosal tissues which is attributable to the release of NO from sinusoidal endothelium and to the potentiation of the cGMP and/or cAMP signal mediating relaxation of cavernosal smooth muscle by inhibiting phosphodiesterase.

Astragalus membranaceus flavonoids (AMF) ameliorate chronic fatigue syndrome induced by food intake restriction plus forced swimming

AIM OF THE STUDY Alteration of immune function may be associated with chronic fatigue syndrome (CFS) and this study reveals the immunoregulatory effect of Astragalus membranaceus flavonoids (AMF). MATERIALS AND METHODS CF rats were induced by food intake restriction plus forced swimming for 6 weeks. RESULTS An atrophied spleen associated with a significantly decreased spleen/body weight ratio and a reduced spleen cells proliferation was found in CF rats when compared with home cage controls. AMF given orally at 20, 50 and 100 mg/kg body weight once a day consecutively for 6 weeks could recover the reduced cell proliferation. A switch to Th1-dominated immune regulation was observed in CF rats as the cultured splenocytes produced more interleukin-2 (IL-2) but less IL-4 when compared with controls. Supplementation with AMF could significantly counteract the aberrant cytokine production and rats received AMF exhibited higher endurance capacity to swim when compared with those without AMF administration. Checking the spectrum signals confirmed that the three major isoflavones contained in AMF were ononin, formononetin, and demethylhomopterocarpin. CONCLUSION Alterations of immune function may be associated with CFS and the tonic effects of AMF against CF may be attributable to balance the abnormal cytokine level by isoflavones.

Betulinic acid stimulates the differentiation and mineralization of osteoblastic MC3T3-E1 cells: involvement of BMP/Runx2 and β-catenin signals

In the field of osteoporosis, there has been growing interest in anabolic agents that enhance bone formation. Here, we examined the effects of betulinic acid on cell proliferation, differentiation, and mineralization of MC3T3-E1 osteoblasts. Then, the impact of betulinic acid on signaling pathways known to be implicated in osteoblastogenesis was explored. Betulinic acid (1-20 microM) markedly increased alkaline phosphatase (ALP) activity and calcium nodule formation, although without a notable effect on cell proliferation. Stimulation with betulinic acid not only increased the osteopontin level and osteocalcin mRNA expression but also upregulated the osteoprotegerin (OPG)/RANKL ratio. Noggin, but not ICI 182780, significantly repressed betulinic acid-induced ALP activity, suggesting a possible action of betulinic acid through the bone morphogenetic protein (BMP) pathway. This was strengthened by the induction of BMP-2 expression, increases in Smad1/5/8 phosphorylation, and Runx2 expression. Furthermore, betulinic acid increased the nuclear level of the active form beta-catenin. These results suggested that betulinic acid has the potential to enhance osteoblastogenesis probably through the activation of BMP/Smad/Runx2 and beta-catenin signal pathways. Furthermore, upregulation of the OPG/RANKL ratio to repress bone catabolism may also indirectly contribute to the bone anabolic effect of betulinic acid.