Suppressive effect of inducible nitric oxide synthase (iNOS) expression by the methanol extract of Actinodaphne lancifolia

Luteoloside attenuates neuroinflammation in focal cerebral ischemia in rats via regulation of the PPARγ/Nrf2/NF-κB signaling pathway

Luteoloside, a flavonoid compound, has been reported to have anti-inflammatory, anti-oxidative, antibacterial, antiviral, anticancer, and cardioprotective effects, among others, but its neuroprotective effects have rarely been studied. The purpose of this study was to investigate the protective effect of luteoloside on cerebral ischemia and explore its potential mechanism. Middle cerebral artery occlusion (MCAO) was performed to investigate the effects of luteoloside on cerebral ischemia-reperfusion (I/R). Male Sprague-Dawley rats were randomly divided into six groups: sham, MCAO, luteoloside (20 mg/kg, 40 mg/kg, 80 mg/kg) and nimodipine (4 mg/kg). The results showed that luteoloside alleviated neurologic deficits and cerebral edema as well as improved cerebral infarction and histopathological changes in MCAO rats. Luteoloside significantly inhibited I/R-induced neuroinflammation, as demonstrated by reduced levels of interleukin-1β (IL-1β), tumor necrosis factor-α (TNF-α), inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) in the brain tissues of MCAO rats. Furthermore, our results demonstrated that luteoloside significantly suppressed the activation of nuclear factor-kappa B (NF-κB) signaling, upregulated the protein expression of peroxisome proliferator activated receptor gamma (PPARγ) and increased NF-E2-related factor (Nrf2) nuclear accumulation in MCAO rats. Collectively, our findings suggested that luteoloside played a crucial neuroprotective role by inhibiting NF-κB signaling in focal cerebral ischemia in rats. Furthermore, PPARγ and Nrf2 were also important for the anti-inflammatory effect of luteoloside. In addition, our data suggested that luteoloside might be an effective treatment for cerebral ischemia and other neurological disorders.

Inhibitory effects of Zataria multiflora essential oil and its main components on nitric oxide and hydrogen peroxide production in lipopolysaccharide-stimulated macrophages

OBJECTIVES

Zataria multiflora is an aromatic plant that is used in flavouring and preserving foods and also used as an antispasmodic, anaesthetic and antinociceptive agent. In this study, the effects of Z. multiflora essential oil on nitric oxide (NO) and hydrogen peroxide (H(2) O(2) ) production in lipopolysaccharide (LPS)-stimulated macrophages was investigated.

METHODS

Z. multiflora essential oil was extracted by water-distillation, analysed by GC-MS and then the effect of the essential oil on NO and H(2) O(2) production was investigated.

KEY FINDINGS

Carvacrol (52%), thymol (16%) and p-cymene (10%) were the main components of the oil. The IC50 (concentration providing 50% inhibition) for reactive oxygen scavenging was estimated to be 5.7, 3 and 4.2 µg/ml for the essential oil, thymol and carvacrol, respectively, while the corresponding IC50 values for reactive nitrogen scavenging were estimated to be 8.6, 4.7 and 6.6 µg/ml. Z. multiflora essential oil, thymol, and carvacrol significantly reduced NO and H(2) O(2) production as well as NO synthase and NADH oxidase activity in LPS-stimulated murine macrophages while p-cymene did not show any antioxidant activity.

CONCLUSIONS

Z. multiflora essential oil has the potential to be used in the therapy of oxidative damage.

The effect of isolancifolide on the apoptosis in HL-60 cells through caspase-8-dependent and -independent pathways

Isolancifolide is a compound extracted and isolated from Actinodaphne lancifolia, which is a traditional oriental medicine. To determine whether isolancifolide has therapeutic potential as an anticancer molecule, we assessed its apoptotic effects on HL-60 cells, a human leukemia cell line. Apoptotic activities were investigated using DNA fragmentation assay, immunoblotting, and flow cytometry. We found that the inhibitory concentration 50% of isolancifolide was approximately 20 M. The time- and dose-dependent effects of isolancifolide on apoptosis were determined by DNA fragmentation and propidium iodide staining, and the involvement of caspases and the Bcl-2 family in isolancifolide-induced apoptosis was assessed by Western blotting. During exposure to isolancifolide, the pro-forms or full length of caspases-8, -3, and Bid were decreased, as assessed by Western blotting, while the levels of cleaved forms of caspases-8, -3, and PARP were increased. We observed that the release of cytochrome c and Smac/DIABLO from the mitochondria to the cytosol was accompanied by the loss of mitochondrial membrane potential. The caspase specific inhibitors, z-IETD-fmk and z-LEHD-fmk, blocked the accumulation of sub-G1 cells and the release of cytochrome c, but not that of Smac/DIABLO. These results indicate that isolancifolide induces apoptosis of HL-60 cells through both death receptor and mitochondria pathways, in caspase-8-dependent and -independent manners, suggesting that isolancifolide may be useful in anticancer strategies.

Involvement of the nitric oxide/soluble guanylate cyclase pathway in the anti-oedematogenic action of Pfaffia glomerata (Spreng) Pedersen in mice

Pfaffia glomerata is used in southern American countries against inflammatory diseases. We have explored the ability of a crude hydroalcoholic extract of P. glomerata root (HEPG) to prevent the oedematogenic action of several inflammatory agents in mice. We have examined also the duration of its effects and the mechanisms involved. The oral or intraperitoneal treatment of mice with HEPG (1, 10, 30, 100 or 300 mg kg−1) reduced, in a dose-dependent manner, carrageenan-induced paw oedema in the early (1–4 h) and late (48 h) periods. In the early period, the ID50 value (the median dose that caused 50% inhibition) of HEPG was 60.5 (28.5–128.71) and 20.4 (14.8–28.3) mg kg−1 after oral and intraperitoneal administration, respectively. This effect was still evident when HEPG was administered up to 6 h before carrageenan. HEPG inhibited also paw oedema induced by histamine, serotonin, bradykinin, substance P and bacterial lipopolysaccharide. In addition, oral administration of HEPG increased the levels of nitrate and nitrite in the blood of mice. Further, its anti-oedematogenic action against carrageenan was prevented fully by NG nitro-L-arginine-methyl-ester (10 mg kg−1, s.c.), as well as by methylene blue (20 mg kg−1, s.c.) or 1H-[1,2,4]oxadiazolo[4,3-alpha]quinoxalin-1-one (2 mg kg−1, s.c.). The results indicated that stimulation of endogenous production of nitric oxide, followed by soluble guanylate cyclase activation, was implicated in the anti-oedematogenic action of HEPG.