[Reasearch on lipid metabolism of Plasmodium and antimalarial mechanism of artemisinin].

As a unicellular organism, Plasmodium displays a panoply of lipid metabolism pathways that are seldom found together in a unicellular organism. These pathways mostly involve the Plasmodium-encoded enzymatic machinery and meet the requirements of membrane synthesis during the rapid cell growth and division throughout the life cycle. Different lipids have varied synthesis and meta-bolism pathways. For example, the major phospholipids are synthesized via CDP-diacylglycerol-dependent pathway in prokaryotes and de novo pathway in eukaryotes, and fatty acids are synthesized mainly via type Ⅱ fatty acid synthesis pathway. The available studies have demonstrated the impacts of artemisinin and its derivatives, the front-line compounds against malaria, on the lipid metabolism of Plasmodium. Therefore, this article reviewed the known lipid metabolism pathways and the effects of artemisinin and its derivatives on these pathways, aiming to deepen the understanding of lipid synthesis and metabolism in Plasmodium and provide a theoretical basis for the research on the mechanisms and drug resistance of artemisinin and other anti-malarial drugs.

Effect of Dihydroartemisinin on Plasmodium NADH-Dependent Glutamate Synthase: The Implication in Malaria Management.

Artemisinin and its analogues (ARTs) are currently the most effective anti-malarial drugs, but the precise mechanism of action is still highly controversial. Effects of ARTs on Plasmodium genes expression are studied in our Lab. The overexpression of an interesting amidotransferase, NADH-dependent glutamate synthase (NADH-GltS) was found in treated by dihydroartemisinin (DHA). The increased expression occurred not only from global transcriptomics analysis on the human malaria parasite Plasmodium falciparum (P. falciparum) 3D7 and gene expression screening on all of iron-sulphur cluster proteins from P.f. 3D7 in vitro but also from Plasmodium berghei (P. berghei) ANKA in mice. Influence of DHA on NADH-GltS was specifically at trophozoite stage of P. falciparum and in a dose-dependent manner below the effective doses. L-glutamine (Gln) and L-glutamate (Glu) are the substrate and product of NADH-GltS respectively. Azaserine (Aza) is specific inhibitor for NADH-GltS. Experimental data showed that Glu levels were significantly decreasing with DHA dose increasing but NADH-GltS enzyme activities were still remained at higher levels in parasites, and appropriate amount of exogenous Glu could significantly reduce anti-malarial action of DHA but excessive amount lost the above effect. Aza alone could inhibit proliferation of P. falciparum and had an additive effect in combination with DHA. Those results could suggest that: Glutamate depletion is one of the anti-malarial actions of DHA; overexpression of NADH-GltS would be a feedback pattern of parasite itself due to glutamate depletion, but not a direct action of DHA; the "feedback pattern" is one of protective strategies of Plasmodium to interfere with the anti-malarial actions of DHA; and specific inhibitor for NADH-GltS as a new type of anti-malarial agents or new partner in ACT might provide a potential.

[Research progress on heme metabolism in intraerythrocytic plasmodium].

Heme is a key metabolic factor in all life. Malaria parasite has de novo heme-biosynthetic pathway, however the growth and development of parasite depend on the hemoglobin-derived heme metabolism process during the intraerythrocytic stages, such as the ingestion and degradation of hemoglobin in the food vacuole. The hemoglobin metabolism in the food vesicles mainly includes four aspects: hemoglobin transport and intake, hemoglobin enzymolysis to produce heme, heme polymerization into malarial pigment, and heme transport via the food vacuole. The potential mechanisms of antimalarial drugs,such as chloroquine, artemisinin and atovaquone may be related to this process. The main four aspects of this metabolic process, key metabolic enzymes, effects of antimalarial drugs on the process and their potential mechanism of action would be summarized in this paper, providing ideas for rational use and mechanism exploration of similar drugs.

[Ferroptosis pathway and its intervention regulated by Chinese materia medica].

Ferroptosis is a new form of regulated cell death which is different from apoptosis, necrosis and autophagy, and results from iron-dependent lipidperoxide accumulation. Now, it is found that ferroptosis is involved in multiple physiological and pathological processes, such as cancer, arteriosclerosis, neurodegenerative diseases, diabetes, antiviral immune response, acute renal failure, hepatic and heart ischemia/reperfusion injury. On the one hand, it could be found the appropriate drugs to promote ferroptosis to clear cancer cells and virus infected cells, etc. On the other hand, we could inhibit ferroptosis to protect healthy cells. China has a wealth of traditional Chinese medicine resources. Chinese medicine contains a variety of active ingredients that regulate ferroptosis. Here, this paper reported the research of ferroptosis pathway, targets of its inducers and inhibitors that have been discovered, and the regulatory effects of the discovered Chinese herbs and its active ingredients on ferroptosis to help clinical and scientific research.

[Protective effects of three phenylallyl compounds from Guizhi decoction ox-LDL-induced oxidative stress injury of human brain microvascular endothelial cells].

The main objective of this research is to observe protective effects of three phenylallyl compounds(cinnamyl alcohol,cinnamaldehyde and cinnamic acid)from Guizhi decoction against ox-LDL-induced oxidative stress injury on human brain microvascular endothelial cells(HBMEC).In this study,the toxicity and optimal protective concentration of three phenylallyl compounds from Guizhi decoction were determined by MTT assay.The HBMEC were divided into control group(DMSO),model group(ox-LDL),tert-butylhydroquinone (t-BHQ) group,cinnamyl alcohol group, cinnamaldehyde group and cinnamic acid group.The model group were treated with ox-LDL (50 mg•L⁻¹)for 24 h,other groups were separately treated with t-BHQ, cinnamyl alcohol, cinnamaldehyde and cinnamic acid of 20 µmol•L⁻¹, and exposed to ox-LDL (50 mg•L⁻¹) for 24 h at the same time.The survival rate of HBMEC was detected by MTT assay,reactive oxygen species(ROS) production of injured cells were detected using laser scanning confocal microscope (LSCM),the content of SOD, MDA, eNOS and NO in HBMEC was determined by ELISA, and the expressions of Nrf2 mRNA were detected by quantitative Real-time PCR(qRT-PCR).The results shows that oxidative stress injury of HBMEC could be induced by ox-LDL, the three phenylallyl compounds from Guizhi decoction did not affect morphology and viability of normal HBMEC.Compared with model group, the three phenylallyl compounds from Guizhi decoction could improve the above oxidative stress status and up-regulate Nrf2 mRNA expressions in injured HBMEC(P<0.05, P<0.01) .These findings suggested that the three phenylallyl compounds from Guizhi decoction have certain protective effects against ox-LDL-induced oxidative stress injury on HBMEC(cinnamaldehyde> t-BHQ> cinnamic acid>cinnamyl alcohol),the protective mechanism maybe related to regulation of antioxidant enzymes gene expression in HBMEC by Nrf2.

Absorptive constituents and their metabolites in drug-containing urine samples from Wuzhishan miniature pigs orally administered with Buyang Huanwu decoction.

Buyang Huanwu decoction (BYHWD), a famous traditional Chinese medicine prescription for the treatment of cerebrovascular diseases, is composed of seven commonly used Chinese herbs--Astragali Radix, Angelicae Sinensis Radix, Paeoniae Radix Rubra, Chuanxiong Rhizoma, Carthami Flos, Persicae Semen and Pheretima. To determine the main absorptive constituents and the metabolites of BYHWD in vivo, urine samples from Wuzhishan (WZS) miniature pigs orally administered with BYHWD (13.6 g crude drugs/kg) were collected to investigate the characteristic compounds. By comparing the high-performance liquid chromatography of a drug-containing urine sample with that of a drug-free sample, 17 characteristic compounds were isolated from the methanol extract of a drug-containing urine sample by column chromatography. Their structures, including 11 isoflavanoids, 2 pterocarpanoids and 4 isoflavonoids, were identified by spectroscopic means. Of the 17 compounds, 8 (1-8) were new compounds with the following structures: 3S-7,3',4'-trihydroxyisoflavan-3'-O-ß-D-glucuronide (1), 3S-7,3',4'-trihydroxyisoflavan-4'-O-ß-D-glucuronide (2), 3S-7,2',4'-trihydroxyisoflavan-2'-O-ß-D-glucuronide (3), 3R-7,2'-dihydroxy-3',4'-dimethoxyisoflavan-2'-O-ß-D-glucuronide (4), 3R-7,2'-dihydroxy-3',4'-dimethoxyisoflavan-2'-O-ß-D-glucuronide-6"-methyl ester (5), 3R-7,2'-dihydroxy-3',4'-dimethoxyisoflavan-7-O-ß-D-glucuronide-6"-methyl ester (6), 3R-7,2',3'-trihydroxy-4'-methoxyisoflavan-3'-O-ß-D-glucuronide-6"-methyl ester (7), and 3S-7,4',5'-trihydroxy-2',3'-dimethoxyisoflavan-5'-O-ß-D-glucuronide (8). Based on the possible relationship and metabolic pathways of the 17 compounds in vivo, 3R-7,2'-dihydroxy-3',4'-dimethoxyisoflavan (isomucronulatol, 11), 6aR,11aR-3-hydroxy-9,10-dimethoxypterocarpan (methylnissolin, astrapterocarpan, 13), 7,3'-dihydroxy-4'-methoxyisoflavone (calycosin, 16) and 7-hydroxy-4'-methoxyisoflavone (formononetin, 17) were thought to be the most important absorptive original isoflavonoid constituents of BYHWD in vivo, which underwent reactions of glucuronidation, hydroxylation, demethylation and reduction. The other 13 compounds were deduced to be their metabolites.

Kinetic study of pentosan solubility during heating and reacting processes of steam treatment of green bamboo.

Green bamboo was hydrolyzed over a range of durations at different temperatures. A simple pseudo-homogeneous irreversible first order kinetic model was developed to describe pentosan solubility during steam treatment of green bamboo. To avoid the influence of soluble pentosan during heating process, kinetic parameters were effectively dissolved based on the data in the reacting process. Moreover, the pentosan solubility during heating process was also well modeled by numerical algorithm method. According to the origin of H factor, a modified parameter called steam treatment factor (f(P)) was proposed in this paper based on the determined kinetic constants. Finally, residual pentosan in whole process could be predicted properly based on the f(P) and the introducing of potential hydrolysis degree (h(d)). After using f(P) to combine reaction temperature and time into a single factor, comparative result showed that steam treatment is more effective for removing pentosan compared with hot water extraction.

[Cinnamaldehyde decreases interleukin-1beta induced PGE2 production by down-regulation of mPGES-1 and COX-2 expression in mouse macrophage RAW264.7 cells].

Cinnamaldehyde was shown to have significant anti-inflammatory and anti-pyretic actions in studies from both others' and our lab. Prostaglandin E2 (PGE2) plays a key role in generation of these pathological states, while PGE, synthase-1 (mPGES-1) is one of crucial biological elements in the process of PGE2 production. And as a downstream inducible terminal prostaglandin synthase of COX-2, mPGES-1 is now regarded as a more promising novel drug target than COX-2 and is attracting more and more attention from both academia and pharmaceutical industry. The purpose of present study was to further investigate the anti-inflammatory and antipyretic molecular mechanisms of cinnamaldehyde based on the mouse macrophage cell line RAW264. 7 in vitro. The PGE2 was identified by using the method of enzyme-linked immunosorbent assay (ELISA) and the expression of COX-2 and mPGES-1 at mRNA and protein levels was detected by the Real-time PCR and Western blotting methods respectively. The experimental results suggested that cinnamaldehyde could evidently reverse the increased production of PGE2induced by IL-1beta. Moreover, the up-regulated expression levels of mPGES-1 and COX-2 were significatly decreased. Together, these results provide compelling evidence that the down-regulated actions to both the production of PGE2 as well as the expression of mPGES-I might account for, at least in part, the anti-inflammatory and anti-pyretic effects of cinnamaldehyde.

Effects of cinnamaldehyde on PGE2 release and TRPV4 expression in mouse cerebral microvascular endothelial cells induced by interleukin-1beta.

Cinnamaldehyde is a principle compound isolated from Guizhi-Tang (GZT), which is a famous traditional Chinese medical formula used to treat influenza, common cold and other pyretic conditions. Transient receptor potential vanilloid subtype 4 (TRPV4) is expressed in the anterior hypothalamus and may act as thermosensor. The purpose of the present study was to investigate the effects of cinnamaldehyde on the production of prostaglandin E2 (PGE2) and the expression of TRPV4 in mouse cerebral microvascular endothelial cell strain (b.End3). In the research work, the b.End3 cells were cultured in DMEM medium containing interleukin-1beta (IL-1beta) in the presence or absence of ruthenium red (RR), a kind of known TRPV4 inhibitor, or different concentrations of cinnamaldehyde. The results suggested that IL-1beta significantly increase production of PGE2 and cinnamaldehyde evidently decrease IL-1beta-induced PGE2 production, while RR showed no inhibitory effect on PGE2 production. Moreover, it was identified that TRPV4 was expressed at the mRNA and protein levels in b.End3 cells. IL-1beta could up-regulate the expression of TRPV4, RR and cinnamaldehyde could down-regulate the high expression of mRNA and protein of TRPV4 by IL-1beta induced in b.End3 cells. In conclusion, cinnamaldehyde decreased the production of PGE2 and the expression of TRPV4 in b.End3 cells induced by IL-1beta.

Effects of 3-phenyl-propenal on the expression of toll-like receptors and downstream signaling components on raw264.7 murine macrophages.

3-phenyl-propenal is one of the principle compounds isolated from Guizhi (Ramulus Cinnamomi), the principal drug in Guizhi-Tang (GZT), a famous traditional Chinese medical formula. The aim of the present study was to investigate the effects of 3-phenyl-propenal on the expression of toll-like receptor 3 (TLR3), TLR4 and the downstream signaling components on Raw264.7 murine microphages. Raw264.7 cells were cultured in RPMI-1640 medium containing LPS (lipopolysaccharide) or poly (I:C) in the presence or absence of 3-phenyl-propenal. After 24-hour incubation, the medium was collected and the amount of TNF-alpha and IFN-beta was measured by ELISA. mRNA expression of TLR3, TLR4, myeloid differentiation factor (MyD88), TRAF-6 (tumor necrosis factor receptor-associated), TRAM (toll-like receptor-associated molecule) and TRIF (TIR domain-containing adaptor inducing IFN-beta) were analyzed by real-time PCR with SYBR green dye. Protein expression of TLR3 and TLR4 was analyzed by Western blotting and that of MyD88 and TRAF-6 was analyzed by immunofluorescence assay. The results indicate that LPS increased the expression of TLR4, MyD88, TRAF-6, TRAM and TRIF, but had no influence on TLR3, while poly (I:C) up-regulated the expression of TLR3, MyD88, TRAM and TRIF. 3-phenyl-propenal significantly decreased the expression of LPS-induced TLR4, MyD88, TRAF-6, while possessing no effect on LPS-induced TRAM and TRIF expression in Raw264.7 cells. When cells were stimulated by poly (I:C), 3-phenyl-propenal significantly decreased TLR3 and MyD88 expression. In conclusion, 3-phenyl-propenal blocked the over-expression of TLR3, TLR4, their downstream signaling components MyD88 and TRAF-6, which indicate that it had an antagonistic effect on TLR3 and TLR4.

[Structure-activity relationship of phenylallyl compounds inhibiting PGE2 release in mouse cerebral microvascular endothelial cells induced by IL-1beta].

To observe the effects of phenylallyl compounds on prostaglandin E2 (PGE2) release in mouse cerebral microvascular endothelial cells (bEnd. 3) stimulated by IL-1beta, and to analyze their structure-activity relationship. Different concentrations of phenylallyl compounds were added separately, and the content of PGE2 induced by IL-1beta in the culture media was measured by ELISA assay. The 50% inhibitory concentration (IC50) of PGE2 was calculated. Studies showed that phenylallyl compounds could affect the PGE2 release differently in bEnd. 3 cells induced by IL-1beta. Close relationships were shown between the inhibitory activities and the location and number of the substituent groups. In conclusion, phenylallyl compounds exhibited inhibitory activities at different extent on PGE2 release in bEnd. 3 cells stimulated by IL-1beta and presented certain structure-activity relationship.

[Effect of Shensu Yin on the expression of toll-like receptors and the downstream signaling components on RAW 264.7 cells].

OBJECTIVE: To investigate the influences of Shensu Yin to RAW 264.7 on the expression of TLR3, TLR4 and the factors of the downstream in RAW 264. 7 cells. METHOD: RAW 264.7 cell line was stimulated with Lipopolysaccharide and POLY I: C, respectively, and treated with the drug serum of Shensuyin simultaneously. 24 hours later, collected the supernatant and measured the inflammatory factors TNF-alpha and IFN-beta, extracted mRNA and measured the expression of TLR3, TLR4 and other correlated indexes of the downstream, analyzed and evaluated Shensu Yin's substance basis of pharmacodynamic actions. RESULT: Shensu Yin drug serum depressed the expression of TLR4, MyD88, TRAF-6, TRAM and TRIF mRNA, as a result, it decreased the amount of TNF-alpha and IFN-beta. CONCLUSION: Depressing the expression of TLR3, MyD88, TRAM and TRIF mRNA may be the elementary basis of Shensu Yin to play heat-clearing and detoxicating effect.

2-methoxycinnamaldehyde reduces IL-1beta-induced prostaglandin production in rat cerebral endothelial cells.

Prostaglandin E2 (PGE2) works as a common final mediator of the febrile. Guizhi-Tang, one of the most famous traditional Chinese medical formula used to treat influenza, common cold and other pyretic conditions, was previously reported to reduce the production of PGE 2 in rats. 2-Methoxycinnamaldehyde is a principle compound isolated from Guizhi-Tang. The aim of the present study was to investigate the effects of 2-methoxycinnamaldehyde on PGE2 production of rat cerebral endothelial cells (CECs). 2-Methoxycinnamaldehyde dose-dependently inhibited interleukin (IL)-1beta-induced PGE2 production in CECs with IC50 values of 174 microM. IL-1beta stimulation increased the protein, activity and mRNA expression of cyclooxygenase (COX)-2 but not COX-1. 2-Methoxycinnamaldehyde reduced IL-1beta-induced protein and activity of COX-2, but did not influence the COX-2 mRNA expression. Our results show that prostaglandin production in CECs during stimulated conditions is sensitive to inhibition by 2-methoxycinnamaldehyde and suggest that 2-methoxycinnamaldehyde may reduce COX-2 protein level and activity but not COX-2 mRNA.

[Effect of guizhi decoction on PKA and PKC activities of hypothalamus in fever rats].

OBJECTIVE: To investigate the changes of the activity of both protein kinase A and C and the mechanisms of antipyretic action of Guizhi decoction. METHOD: The fever responses were observed after combination injection of H-89 (a selective inhibitor of PKA) and calphostin C (a selective inhibitor of PKC), and oral pretreatment of Guizhi decoction in fever rats induced by an intra-cerebroventricular (icv) injection of an EP3 agonist, and both PKA and PKC activity in hypothalamus were measured in rats pretreated with Guizhi decoction and vehicle using isotopic tracing assay. RESULT: The rise in rat body temperature was inhibited by H-89, Calphostin C, and Guizhi decoction, moreover, pretreatment with Guizhi decoction reduced PKA activity obviously. PKC activity in model rats exhibited a tendency to drop compared with that of control group, Oral administration of Guizhi decoction in large dose inhibited the response significantly, while the low dose of Guzhi decoction has no effect on PKC. CONCLUSION: Both PKA and PKC may participate in the mechanism of fever induction by EP3 agonist. The decrease of PKA and PKC may contribute to the antipyretic action of Guizhi decoction, some isoenzyme of PKC may play a role in the fever production.

[Effect of guizhi tang and its active components on the fever induced by EP3 agonist].

OBJECTIVE: To investigate the effect of Guizhi Tang and its active components on the fever induced by EP3 receptor agonist sulprostone in rats. METHOD: The rise in body temperature evoked by a LCV(lateral cerebroventricle)-injection of sulprostone was compared with that of sulprostone induced-fever rats pretreated with Guizgi Tang and its active compounds, cinnamaldehyde, cinnamic acid and total glucosides of paeony. RESULT: Pretreatments with Guizhi Tang and cinnamaldehyde inhibited the rise in body temperature induced by sulprostone, while cinnamic acid tended to augment the fever. The sulprostone-induced fever was blocked by an ip pretreatment of total glucosides of paeony even below the basement. CONCLUSION: Present data suggest that interruption with the down-stream events of EP3 receptor may contribute to the antipyretic action of Guizhi Tang, cinnamaldehyde and the total glucosides of paeony, while cinnamic acid may have no such effect.