Antioxidant Activities In Vitro and Hepatoprotective Effects of Nelumbo Nucifera Leaves In Vivo

Background

Herbal medicines played a major role in the treatment of hepatic disorders, and a number of medicinal plants and their compounds were widely used for the treatment of these disorders, and oxidant stress injury was one of the mechanism of liver injury.

Materials and Methods

Antioxidant activity of Nelumbo nucifera leaves (NU) extracts was assayed by the methods of scavenging 1,1-diphenyl-2-picrylhydrazyl (DPPH), 2,2′-azino-bis (3-ethylbenzo-thiazoline-6-sulfonicacid) (ABTS) radical and ferric reducing antioxidant power (FRAP) in vitro. By intraperitoneal injection carbon tetrachloride (CCl₄) to establish acute liver injury model in mice, the levels of Glutamic-pyruvic transaminase (GPT), glutamic-oxaloacetic transaminase (GOT), superoxide dismutase (SOD) and the content of and maleicdialdehyde (MDA) were detected to evaluate hepatoprotective effect of NU using corresponding test kit.

Results

EtOAC (NUEA) and n-BuOH extracts (NUBU) of N. nucifera leaves had good scavenging DPPH and ABTS radical activity and ferric reducing antioxidant power in vitro. DPPH radical scavenging activity and ferric reducing antioxidant power of NUEA (IC₅₀= 6.68±0.29 µg/mL, RACT₅₀=1749.82±67.03 µmol/g) and NUBU (IC₅₀= 4.61±0.01 µg/mL, RACT₅₀=1995.27±135.71 µmol/g ) were higher than that of BHT (IC₅₀=8.76±0.20 µg/mL, RACT₅₀=1581.68±97.41 µmol/g) and Dangfeiliganning (IC₅₀=28.06±0.17 µg/mL, RACT₅₀=1028.55±3.28 µmol/g). ABTS radical scavenging activity of NUEA (IC₅₀= 5.32±0.12 µg/mL) and NUBU (IC₅₀= 8.16±0.27 µg/mL) were higher than that of Dangfeiliganning (IC₅₀= 9.76±0.16 µg/mL). Thus, hepatoprotective effect of NUEA and NUBU was evaluated on CCl₄-induced acute liver injury mice. The results showed that the levels of GOT and GPT in each treatment group significantly decreased (p<0.001 and p<0.01, p<0.05, respectively) except for the group of NUEA (130.8 mg/kg) (p>0.05). The contents of malondialdehyde (MDA) in liver in groups of NUEA (523 mg/kg), NUBU (840.5 and 420.5 mg/kg, repectively) had significant decrease (p<0.001 and p<0.05, respectively), and the level of SOD in liver for each treatment group could significantly decrease (p<0.001, p<0.05, respectively).

Conclusion

NUEA and NUBU had significantly hepatoprotective effect for Calcium tetrachloride CCl₄-induced liver injury, which might be attributable to its antioxidant activity.     

Endothelium-Independent and Endothelium-Dependent Vasorelaxation by a Dichloromethane Fraction from Anogeissus Leiocarpus (DC) Guill. Et Perr. (Combretaceae): Possible Involvement of Cyclic Nucleotide Phosphodiesterase Inhibition

Many traditional medicinal herbs from Burkina Faso are used to treat arterial hypertension (HTA). Among them, Anogeissus leiocarpus (A. Leiocarpus) which is well known and widely used in Burkina traditional medicine. Herein we assess the effects of dichloromethane fraction from A. leiocarpus stem bark (ALF), selected as the most active on cyclic nucleotide phosphodiesterases (PDEs) and characterized its specificity towards purified vascular PDE1 to PDE5 isoenzymes and study its effects on a vascular model. ALF potently and preferentially inhibits (IC₅₀=1.6 ± 0.6 µg/mL) the calmodulin-dependent phosphodiesterase PDE1, being mainly present in vascular smooth muscle and preferentially hydrolyses cGMP. In the same range (IC₅₀ =2.8 ±0.2 µg/ml) ALF inhibits PDE2, a cGMP-activated enzyme that is only present in endothelial cells and hydrolyses both cAMP and cGMP. PDE5, which specifically hydrolyses cGMP and which mainly contributes to cGMP hydrolysis is also potently inhibited by ALF (IC₅₀=7.6±3.5 µg/ml). The potencies of ALF on cAMP hydrolyzing isoenzymes was lesser, being more effective on PDE4 (IC₅₀= 17.6±3.5 µg/ml) than on PDE3 (60.9 ± 1.8 µg/ml). Since the major effect of ALF were against cGMP hydrolysis and since cGMP is implicated in endothelium-dependent relaxation, the endothelium-dependent vasorelaxation was studied on isolated porcine coronary arteries rings pre-contracted with U46619. The endothelium-dependent vasorelaxation is significantly inhibited by N^ω-nitro-L-arginine (LNA 300 µmol/L, an inhibitor of endothelial NO synthase), but not affected by charybdotoxin (CTX, 100nM) plus apamin (APA, 100nM) (two inhibitors of EDHF-mediated responses). The combination of 4-aminopyridine (4-AP, 1 mmol/L, inhibitor of voltage-dependent potassium channels, K_v) plus baryum (Ba²⁺, 30 µmol/L, inhibitor of the potassium channels with entering correction, K_ir) plus ouabain (3 µmol/L, inhibitor of ATPase Na⁺/K⁺ channels) partially inhibits endothelium-independent vasorelaxant effect. This endothelium-independent relaxant effect was also sensitive to combination of 1H-[1,2,4]-oxadiazole-[4,3-α]-quinoxalin1-one (ODQ, 10 µM, soluble guanylyl cyclase inhibitor) and N-[2-(p-Bromocinnamylamino)ethyl]-5-isoquinoline sulfonamide dihydrochloride (H89, 100 nM, Protein Kinase A inhibitor). Taken together, these results indicate that ALF is a powerful vasodilator modulated by the formation of NO from endothelium, but also act by directly relaxing the vascular smooth muscle cells, by inhibiting cGMP hydrolyzing PDEs (PDE1, PDE2 and PDE5) and to a lesser extend on cAMP degradation (PDE3 and PDE4), cAMP and cGMP being second messengers involved in vascular relaxation.     

Study on In Vitro Anti-Tumor Activity of Bidens Bipinnata L. Extract

We studied the in vitro anti-tumor activity of Bidens Bipinnata L. extract. MTT assay was used to investigate the inhibitory effect of different concentrations of the extracts on human hepatocellular carcinoma (HepG2) cell lines and human cervical carcinoma (Hela) cell lines, and the IC₅₀ values were calculated. The Bidens Bipinnata L. extract had different degrees of inhibitory effects on these two cells, and when exposure time was 48 h, the inhibition rate reached its peak, with IC₅₀ values of 14.80 µg/mL and 13.50 µg/mL respectively. The Bidens Bipinnata L. extract had a good inhibitory effect on human HepG2 cell lines and Hela cell lines, and thus has certain development prospects.     

In vitro anti-inflammatory,cytotoxic and antioxidant activities of boesenbergin A,a chalcone isolated from Boesenbergia rotunda (L.) (fingerroot)

The current in vitro study was designed to investigate the anti-inflammatory, cytotoxic and antioxidant activities of boesenbergin A (BA), a chalcone derivative of known structure isolated from Boesenbergia rotunda. Human hepatocellular carcinoma (HepG2), colon adenocarcinoma (HT-29), non-small cell lung cancer (A549), prostate adenocarcinoma (PC3), and normal hepatic cells (WRL-68) were used to evaluate the cytotoxicity of BA using the MTT assay. The antioxidant activity of BA was assessed by the ORAC assay and compared to quercetin as a standard reference antioxidant. ORAC results are reported as the equivalent concentration of Trolox that produces the same level of antioxidant activity as the sample tested at 20 µg/mL. The toxic effect of BA on different cell types, reported as IC₅₀, yielded 20.22 ± 3.15, 10.69 ± 2.64, 20.31 ± 1.34, 94.10 ± 1.19, and 9.324 ± 0.24 µg/mL for A549, PC3, HepG2, HT-29, and WRL-68, respectively. BA displayed considerable antioxidant activity, when the results of ORAC assay were reported as Trolox equivalents. BA (20 µg/mL) and quercetin (5 µg/mL) were equivalent to a Trolox concentration of 11.91 ± 0.23 and 160.32 ± 2.75 µM, respectively. Moreover, the anti-inflammatory activity of BA was significant at 12.5 to 50 µg/mL and without any significant cytotoxicity for the murine macrophage cell line RAW 264.7 at 50 µg/mL. The significant biological activities observed in this study indicated that BA may be one of the agents responsible for the reported biological activities of B. rotunda crude extract.     

In Vitro Activity of Tigecycline Against Orientia tsutsugamushi

Scrub typhus is a zoonosis caused by Orientia tsutsugamushi (O. tsutsugamushi) occurring mainly in autumn in Korea. The need of new antibiotics has arisen with a report on strains resistant to antibiotics and chronic infection. This study aims to identify susceptibility of tigecycline in-vitro as a new therapeutic option for O. tsutsugamushi. Antibacterial activity of tigecycline against the O. tsutsugamushi was compared with doxycycline using flow cytometry assay. The inhibitory concentration 50 (IC₅₀) was 3.59×10^-3 µg/mL in doxycycline-treated group. Whereas in 0.71×10^-3 µg/mL tigecycline-treated group. These findings indicate that tigecycline may be a therapeutic option for the treatment of scrub typhus.     

Anxiolytic effects of repeated treatment with an essential oil from Lippia alba and (R)-(-)-carvone in the elevated T-maze

Lippia alba (Mill.) N.E. Brown (Verbenaceae) is widely used in different regions of Central and South America as a tranquilizer. The plant''s anxiolytic properties, however, merit investigation. The present study evaluated the effects of repeated daily (14 days) intraperitoneal (ip) treatment with an essential oil (EO) from a chemotype of L. alba (LA, chemotype II, 12.5 and 25 mg/kg; N = 6-8) and (R)-(-)-carvone (25 mg/kg; N = 8-12), the main constituent of this chemotype, on male Wistar rats (weighing 250 g at the beginning of the experiments) submitted to the elevated T-maze (ETM). The ETM allows the measurement of two defensive responses: inhibitory avoidance and one-way escape. In terms of psychopathology, these responses have been related to generalized anxiety and panic disorder, respectively. Treatment with the EO impaired ETM avoidance latencies, without altering escape, in a way similar to the reference drug diazepam (P < 0.05) (avoidance 2: control = 84.6 ± 35.2; EO 12.5 mg/kg = 11.8 ± 3.8; EO 25 mg/kg = 14.6 ± 2.7; diazepam = 7 ± 2.1). (R)-(-)-carvone also significantly altered this same response (P < 0.05; avoidance 1: control = 91.9 ± 31.5; carvone = 11.6 ± 1.8; diazepam = 8.1 ± 3.3). These results were not due to motor changes since no significant effects were detected in an open field. These observations suggest that LA exerts anxiolytic-like effects on a specific subset of defensive behaviors that have been implicated in generalized anxiety disorder, and suggest that carvone is one of the constituents of LA responsible for its action as a tranquilizer.     

Anticancer Constituents and Cytotoxic Activity of Methanol-Water Extract of Polygonum Bistorta L.

This study was specifically designed to identify anticancer constituents in methanol-water extract of Polygonum bistorta L. and evaluate its cytotoxicity. For this purpose methanol-water (40:60 v/v) extract was subjected to conventional preparative high pressure liquid chromatography and 13 fractions were obtained. Constituents of obtained fractions were separated and identified with the help of GC-MS and LC-DAD-ESI-MS. Anticancer phenolic compounds such as gallic acid, protocatechuic acid, p-hydroxybenzoic acid, chlorogenic acid, vanillic acid, syringic acid, catechol, 4-methyl catechol, syringol and pyrogallol and fatty acids such as linoleic acid, myristic acid and palmitic acid were separated from different fractions. Fractions were evaluated for their cytotoxic activity on a rarely studied human hepatocellular carcinoma cell line (HCCLM3). 11 fractions showed good to strong cytotoxicity in a range of 200 µg/mL-800 µg/mL, whereas 2 fractions did not show any activity even at 800 µg/mL and no anticancer constituent was detected from them. 50 percent growth inhibition (GI₅₀) values for five most active fractions were calculated and results were in a range of 86.5 (±3) µg/mL–126.8 (±3) µg/mL. 3 out of these 5 most active fractions were found to contain phenolic content in them whereas all other fractions containing phenolic content did possess cytotoxic activity that may suggest the importance of phenolic constituents in anticancer activity. Moreover, the results also showed a definite dose dependent relationship between amount of fractions and cytotoxic activity.     

Anti-Inflammatory,Cytotoxic and Antioxidant Effects of Methanolic Extracts of Drypetes Sepiaria (Euphorbiaceae)

The aim of this study was to investigate in vitro antioxidant, anti-inflammatory and cytotoxic activities of the petroleum ether, ethyl acetate, methanol and aqueous extracts obtained from leaves of Drypetes sepiaria (Euphorbiaceae). Total phenolic and flavonoid contents of these crude extracts were determined as gallic acid and quercetin equivalents, respectively. In in vitro antioxidant method, methanol extract exhibited higher free radical scavenging activity compared to standard compound, ascorbic acid with IC₅₀ of 95.43µg/ml (DPPH) and 67.05µg/ml (ABTS). Methanol extract was able to inhibit inflammation by in vitro about 85–90% (HRBC stabilization method) and in vivo about 40–45% (Paw oedema method) anti-inflammatory assays compared to standard produced 50.04% at 6h period. In cytotoxicity assay (MTT assay) methanolic extract exhibited IC₅₀ of 10µg/ml. In apoptosis (flow cytometric assay), the control group showed normal caspase 3 activity in the SiHa cells which was 0.24%, and increased up to 40% after treatment.     

Participation of the GABAergic system in the anesthetic effect of Lippia alba (Mill.) N.E. Brown essential oil

The objective of this study was to identify the possible involvement of the GABAergic system in the anesthetic effect of Lippia alba essential oil (EO). We propose a new animal model using silver catfish (Rhamdia quelen) exposed to an anesthetic bath to study the mechanism of action of EO. To observe the induction and potentiation of the anesthetic effect of EO, juvenile silver catfish (9.30 ± 1.85 g; 10.15 ± 0.95 cm; N = 6) were exposed to various concentrations of L. alba EO in the presence or absence of diazepam [an agonist of high-affinity binding sites for benzodiazepinic (BDZ) sites coupled to the GABA_A receptor complex]. In another experiment, fish (N = 6) were initially anesthetized with the EO and then transferred to an anesthetic-free aquarium containing flumazenil (a selective antagonist of binding sites for BDZ coupled to the GABA_A receptor complex) or water to assess recovery time from the anesthesia. In this case, flumazenil was used to observe the involvement of the GABA-BDZ receptor in the EO mechanism of action. The results showed that diazepam potentiates the anesthetic effect of EO at all concentrations tested. Fish exposed to diazepam and EO showed faster recovery from anesthesia when flumazenil was added to the recovery bath (12.0 ± 0.3 and 7.2 ± 0.7, respectively) than those exposed to water (9.2 ± 0.2 and 3.5 ± 0.3, respectively). In conclusion, the results demonstrated the involvement of the GABAergic system in the anesthetic effect of L. alba EO on silver catfish.     

The Inhibitory Activity of the Extracts of Popular Medicinal Herbs on CYP1A2, 2C9, 2C19 and 3A4 and the Implications for Herb-Drug Interaction

Background

Studies have suggested an increasing practice of concurrent herb-drug consumption. One of the major clinical risks of such concomitant herb-drug use is pharmacokinetic herb-drug interaction (HDI). This is brought about by the ability of phytochemicals to inhibit or induce the activity of metabolic enzymes. The aim of this study was to investigate the potential of the crude aqueous extracts of three popular medicinal herbs used in South Africa to inhibit major cytochrome P450 (CYP) enzymes.

Materials and Methods

The extracts of Bowiea volubilis, Spirostachys africana and Tulbaghia violacea were incubated with human liver microsomes (HLM) to monitor the phenacetin O-deethylation, diclofenac 4′-hydroxylation, S-mephenytoin 4′-hydroxylation and testosterone 6β-hydroxylation as respective probe reactions for CYP1A2, CYP2C9, CYP2C19 and CYP3A4. The inhibitory activity, where observed, was profiled against the extract concentration.

Results

Extracts of Bowiea volubilis inhibited the metabolic activity of CYP1A2 and CYP3A4 with IC₅₀ values of 92.3 ± 5.5 µg/mL and 8.1 ± 0.6 µg/mL respectively. Similar observation with Spirostachys africana showed inhibitory activity against CYP1A2 and CYP3A4 with respective IC₅₀ values of 14.3 ± 0.6 µg/mL and 47.4 ± 2.4 µg/mL. Tulbaghia violacea demonstrated relatively weak inhibitory activity against CYP1A2 (767.4 ± 10.8 µg/mL) and CYP2C9 (921 ± 15.3 µg/mL).

Conclusion

The results suggest the potential for HDI between the herbs and the substrates of the affected enzymes, if sufficient in vivo concentration is attained.     

Evaluation of Three Medicinal Plant Extracts Against Plasmodium Falciparum and Selected Microganisms

Background

A great revival of scientific interests in drug discovery has been witnessed in recent years from medicinal plants for health maintenance. The aim of this work was to investigate three Nigerian medicinal plants collected in Nigeria for their in vitro antiplasmodial and antimicrobial activities.

Materials and Methods

Extracts obtained from parts of Persea americana, Jatropha podagrica and Picralima nitida and their fractions were evaluated for in vitro antiprotozoal and antimicrobial activity.

Result

The methanol extract of P. nitida demonstrated activity against chloroquine-sensitive and chloroquine-resistant P. falciparum clones with IC₅₀ values of 6.3 and 6.0 µg/mL, respectively. Methanol and chloroform extracts of P. americana seed showed antifungal activity against Cryptococcus neoformans IC₅₀ less than 8 and 8.211 µg/mL respectively. Finally, the petroleum ether extract of P. americana had activity against methicillin-resistant Staphylococcus aureus (MRSA) with an IC₅₀ value of 8.7 µg/mL.

Conclusion

The study revealed the antibacterial and antiplasmodial activities of the plants extracts at the tested concentrations.     

In vitro antifungal activity of epigallocatechin 3-O-gallate against clinical isolates of dermatophytes

Previously, we reported that epigallocatechin 3-O-gallate (EGCg) has growth-inhibitory effect on clinical isolates of Candida species. In this study, we investigated the antifungal activity of EGCg and antifungal agents against thirty-five of dermatophytes clinically isolated by the international guidelines (M38-A2). All isolates exhibited good susceptibility to EGCg (MIC₅₀, 2-4 µg/mL, MIC₉₀, 4-8 µg/mL, and geometric mean (GM) MICs, 3.36-4 µg/mL) than those of fluconazole (MIC₅₀, 2-16 µg/mL, MIC₉₀, 4-32 µg/mL, and GM MICs, 3.45-25.8 µg/mL) and flucytosin (MIC₅₀, MIC₉₀, and GM MICs, >64 µg/mL), although they were less susceptible to other antifungal agents, such as amphotericin B, itraconazole, and miconazole. These activities of EGCg were approximately 4-fold higher than those of fluconazole, and were 4 to 16-fold higher than flucytosin. This result indicates that EGCg can inhibit pathogenic dermatophyte species. Therefore, we suggest that EGCg may be effectively used solely as a possible agent or combined with other antifungal agents for antifungal therapy in dermatophytosis.     

In Vitro Bacteriostatic Effects of Rifampin on Orientia tsutsugamushi

We performed an in vitro cell culture experiment to ascertain whether rifampin exhibits bactericidal effects against Orientia tsutsugamushi, the causative agent of scrub typhus. ECV304 cells were infected with the Boryong or AFSC-4 strain of O. tsutsugamushi and then, the cultures were maintained in media with increasing concentrations of rifampin, azithromycin, doxycycline, or chloramphenicol for 4 days. On day 5, the media were replaced with fresh antibiotic-free medium and the cultures were maintained until day 28. On days 5, 13, and 28, immunofluorescence (IF) staining of O. tsutsugamushi was performed. IF staining on days 13 and 28 revealed increasing numbers of IF-positive foci in all cultures, even in cultures initially exposed to the highest concentration of rifampin (80 µg/mL), azithromycin (80 µg/mL), doxycycline (20 µg/mL), or chloramphenicol (100 µg/mL). The present study reveals that rifampin has no bactericidal effect against O. tsutsugamushi as observed for azithromycin, doxycycline, and chloramphenicol. A subpopulation of the bacteria that are not killed by high concentrations of the antibiotics may explain the persistence of O. tsutsugamushi in humans even after complete recovery from scrub typhus with antibiotic therapy.

Graphical Abstract

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Antioxidant Activity In Vitro and Hepatoprotective Effect of Phlomis Maximowiczii In Vivo

Background

A number of medicinal plants and there compounds played a major role in the treatment of hepatic disorders. They were widely used for the treatment of these disorders, and oxidant stress injury was one of the liver injury mechanisms. The present study evaluated the antioxidant activity and the hepatoprotective effect of each extracts of Phlomis maximowiczii.

Materials and Methods

The antioxidant activity was assayed by the methods of ABTS, FRAP and DPPH in vitro. Hepatoprotective effect of P. maximowiczii extracts was examined using carbon tetrachloride-induced acute liver injury in mice.

Results

P. maximowiczii n-butanol (PMBU) extract, ABTS (IC₅₀=18.96 µg/mL), DPPH (IC₅₀=25.15 µg/mL), and FRAP (RACT₅₀=2775.6±144.18 µmol/g), showed higher scavenging capacity than that of P. maximowiczii ethyl acetate (PMEA). The n-butanol extract could significantly reduce the level of GPT, GOT and MDA (P<0.05, P<0.001 and P<0.001, respectively) and increase the level of SOD (P<0.001), respectively.

Conclusion

The antioxidant activity of n-butanol extract in vitro was related with the level of MDA and SOD in vivo, and hepatoprotective effect of n-butanol extract also had relationship with its antioxidant activity in vivo.     

Antiproliferative Effect of Alcoholic Extracts of Some Gabonese Medicinal Plants on Human Colonic Cancer Cells

Extracts from Piptadeniastrum africanum Brenan (Mimosaceae), Petersianthus macrocarpus (Breauv) L. (Lecydaceae), Cissus debilis Planch (Vitaceae) and Dieffenbachia seguine Jacq. (Araceae) were tested in vitro for their antiproliferative activity on human colon cancer cell line (CaCo-2). The highest antiproliferative activities were obtained with the alcoholic extracts of the roots of Piptadeniastrum africanum (G-PAR), the leaves of Petersianthus macrocarpus (G-PMF) and the stem of Cissus debilis (G-CDL), with 50% inhibition concentrations (IC₅₀) of 15 µg/ml, 17 µg/ml and 25 µg/ml respectively. Only one extract (leaves of Dieffenbachia seguine (G-DSF)) exhibited weak antiproliferative activity with 50% inhibition concentration (IC₅₀) higher than 50 µg/ml.     

In Vitro Analysis of Antioxidant Activities of Oxalis Corniculata Linn. Fractions in Various Solvents

As part of our search for natural antioxidants, this work presents an evaluation of antioxidant activities of methanolic extract of Oxalis corniculata and its sub-fractions in hexane, chloroform, ethyl acetate, n-butanol and water. The total phenolic contents in terms of µg of gallic acid equivalents per mg of dried mass were approximately 21.0, 28.2, 34.5, 162.0, 70.0, and 49.2 in methanolic, hexane, chloroform, ethyl acetate, n-butanolic and aqueous fractions respectively, while the flavonoid contents in these solvents were 362.4, 214.1, 317.1, 177.1, 98.8 and 53.5 respectively in terms of µg of rutin per mg of dried mass. In DPPH assay, the ethyl acetate fraction showed the highest free radical scavenging activity, 24.0% with 1 mg/mL concentration. The second strongest fraction was chloroform (21.5%). The EC₅₀ and TEC₅₀ values of the methanolic extract were 3.63 mg/mL and 23 min respectively. The FRAP values in terms of µg of ascorbic acid equivalents per mg of dried mass for these solvents were 288.0, 1705.3, 437.1, 72.0, 28.0, and 44.0 respectively while total antioxidant activity measured by phosphomolybdate assay in terms of µg of ascorbic acid equivalents per mg of dried mass were 50.0, 117.0, 78.6, 57.8, 3.4 and 8.3 respectively. All the samples showed remarkable ability to inhibit lipid peroxidation exhibiting much better and sustainable peroxidation inhibitory activity than the standard butylated hydroxyanisole.     

The hydrogen sulfide donor,Lawesson's reagent,prevents alendronate-induced gastric damage in rats

Our objective was to investigate the protective effect of Lawesson''s reagent, an H₂S donor, against alendronate (ALD)-induced gastric damage in rats. Rats were pretreated with saline or Lawesson''s reagent (3, 9, or 27 µmol/kg, po) once daily for 4 days. After 30 min, gastric damage was induced by ALD (30 mg/kg) administration by gavage. On the last day of treatment, the animals were killed 4 h after ALD administration. Gastric lesions were measured using a computer planimetry program, and gastric corpus pieces were assayed for malondialdehyde (MDA), glutathione (GSH), proinflammatory cytokines [tumor necrosis factor (TNF)-α and interleukin (IL)-1β], and myeloperoxidase (MPO). Other groups were pretreated with glibenclamide (5 mg/kg, ip) or with glibenclamide (5 mg/kg, ip)+diazoxide (3 mg/kg, ip). After 1 h, 27 µmol/kg Lawesson''s reagent was administered. After 30 min, 30 mg/kg ALD was administered. ALD caused gastric damage (63.35±9.8 mm²); increased levels of TNF-α, IL-1β, and MDA (2311±302.3 pg/mL, 901.9±106.2 pg/mL, 121.1±4.3 nmol/g, respectively); increased MPO activity (26.1±3.8 U/mg); and reduced GSH levels (180.3±21.9 µg/g). ALD also increased cystathionine-γ-lyase immunoreactivity in the gastric mucosa. Pretreatment with Lawesson''s reagent (27 µmol/kg) attenuated ALD-mediated gastric damage (15.77±5.3 mm²); reduced TNF-α, IL-1β, and MDA formation (1502±150.2 pg/mL, 632.3±43.4 pg/mL, 78.4±7.6 nmol/g, respectively); lowered MPO activity (11.7±2.8 U/mg); and increased the level of GSH in the gastric tissue (397.9±40.2 µg/g). Glibenclamide alone reversed the gastric protective effect of Lawesson''s reagent. However, glibenclamide plus diazoxide did not alter the effects of Lawesson''s reagent. Our results suggest that Lawesson''s reagent plays a protective role against ALD-induced gastric damage through mechanisms that depend at least in part on activation of ATP-sensitive potassium (K_ATP) channels.     

Antibacterial Activity of a Cardanol from Thai Apis mellifera Propolis

Background: Propolis is a sticky, dark brown resinous residue made by bees that is derived from plant resins. It is used to construct and repair the nest, and in addition possesses several diverse bioactivities. Here, propolis from Apis mellifera from Nan province, Thailand, was tested for antibacterial activity against Gram^+ve (Staphylococcus aureus and Paenibacillus larvae) and Gram^-ve (Escherichia coli) bacteria.Materials and methods: The three bacterial isolates were confirmed for species designation by Gram staining and analysis of the partial sequence of 16S rDNA. Propolis was sequentially extracted by methanol, dichloromethane and hexane. The antibacterial activity was determined by agar well diffusion and microbroth dilution assays using streptomycin as a positive control. The most active crude extract was further purified by quick column and adsorption chromatography. The apparent purity of each bioactive fraction was tested by thin layer chromatography. The chemical structure of the isolated bioactive compound was analyzed by nuclear magnetic resonance (NMR).Results: Crude methanol extract of propolis showed the best antibacterial activity with a minimum inhibition concentration (MIC) value of 5 mg/mL for S. aureus and E. coli and 6.25 mg/mL for P. larvae. After quick column chromatography, only three active fractions were inhibitory to the growth of S. aureus and E. coli with MIC values of 6.25 and 31.3 µg/mL, respectively. Further adsorption chromatography yielded one pure bioactive fraction (A1A) with an IC₅₀ value of 0.175 µg/mL for E. coli and 0.683 µg/mL for P. larvae, and was determined to be cardanol by NMR analysis. Scanning and transmission electron microscopy analysis revealed unusual shaped (especially in dividing cells), damaged and dead cells in cardanol-treated E. coli.Conclusion: Thai propolis contains a promising antibacterial agent.     

Anti-Inflammatory,Antioxidant, and Selective Antibacterial Effects of Euadenia Eminens Root Bark

Euadenia eminens Hook f. (Capparaceae) has traditional uses in the management of conjunctivitis, iritis, ophthalmia, tuberculosis, otalgia and rectal prolapse. The fruit pulp is also eaten as an aphrodisiac. In this paper, we report on the anti-inflammatory, antioxidant and antibacterial effects of its roots. A 70 % ethanol extract was tested for anti-inflammatory effect using the carrageenan-induced oedema in chicks. Free radical scavenging, total antioxidant and total phenol content were assessed spectrophotometrically. The extract was tested for antibacterial activity using the agar well diffusion method and micro dilution assays. The 70% ethanol extract gave a maximal inhibition of oedema by 74.18 % at 30 mg/kg. The total antioxidant capacity expressed in terms of ascorbic acid was 0.609 mg/g dry weight. The total phenol in terms of tannic acid was 7.25 mg/g dry weight. The extract also demonstrated free radical scavenging activity yielding IC₅₀ value of 1.175 mg/mL. The root extract however, showed selective antibacterial activity, inhibiting growth of two microorganisms; Bacillus subtilis and Bacillus thurigiensis. The MICs were 500 and 1000 µg/mL respectively. These results may account in part for the ethnopharmacological use of the plant.     

Acute Toxicity and Vascular Properties of Seed of Parkia Biglobosa (JACQ) R. Br Gift (Mimosaceae) on Rat Aorta

The authors report here the results of study on Parkia biglobosa seeds used in Burkina Faso for arterial hypertension treatment. Investigations were done on acute toxicity and vascular properties of fermented and roasted seeds. Acute toxicity test using mice, revealed by the intraperitoneal route a lethal dose 50 (LD₅₀) of 1800 mg/kg and 1600 mg/kg of body weight for aqueous extract from roasted and fermented seeds respectively. According to the scale of Hodge and Sterner and that of the World Health Organization, such drugs would be classified lightly toxic. Oral administration (up to 3000 mg/kg) did not induce any death of animal. For the vascular properties, the effects of these products were tested on the aorta isolated from rats. The cumulative administration of extract from roasted and fermented seeds (0.1–10 mg/mL) in an organ bath induced a concentration-dependent relaxation of the aorta pre contracted by phenylephrine, with or without functional endothelium. The extracts (10 mg/mL) inhibited for 100% the contraction induced by phenylephrine. The EC₅₀ values in presence and absence of endothelium were respectively of 5.37 ± 0.12 and 4.19 ± 1.02 mg/mL for fermented seeds; for roasted seeds these values were respectively, 5.39 ± 1.12 and 5.93 ± 0.95 mg/mL. Nevertheless, low concentration of roasted seeds (1–4 mg/mL) induced endothelium-dependent relaxation and this effect was inhibited by indomethacin (10⁻⁵M), and not by L-NAME (310⁻⁴M). These experimental results revealed a vasorelaxant effect of P. biglobosa seeds. P. biglobosa seems to act directly on the smooth muscle and via endothelium involving the generation of vasodilatating prostaglandins. This vasodilator effect would be in favor of an anti hypertensive property of P. biglobosa seeds.