Attenuation of airway hyperreactivity and T helper cell type 2 responses by coumarins from Peucedanum praeruptorum Dunn in a murine model of allergic airway inflammation

Ethnopharmacological relevance

The root of Peucedanum praeruptorum Dunn (PPD) is a commonly used traditional Chinese medicine for the treatment of asthma. Its major constituents, coumarins, were presumed to be responsible for its efficacy.

Aim of the study

The potential of coumarins from PPD (CPPD) as anti-asthma agent was investigated.

Materials and methods

Female BALB/c mice were sensitized and challenged with ovalbumin (OVA) to induce allergic airway inflammation. CPPD was administered intragastrically before every OVA challenge. Airway reactivity to the intravenous administration of acetylcholine chloride was measured 48 h after final OVA inhalation. Airway inflammation was evaluated by leukocyte counts of bronchoalveolar lavage fluid (BALF) and histopathological analysis of lung lesions. Levels of interleukin (IL)-4, IL-5, IL-10, IL-13 and IFN-γ in BALF and OVA-specific immunoglobulin (Ig) E in serum, and activity of eosinophil peroxidase (EPO) in lung was measured. The percentage of CD4⁺CD25⁺Foxp3⁺ regulatory T cells among CD4⁺ T cells in spleen was analyzed by flow cytometry.

Results

Compared with model group, CPPD significantly reduced airway hyperreactivity and airway eosinophilic inflammation, improved pathologic lesion of the lungs, reduced levels of IL-4, IL-5, IL-13 in BALF and OVA-specific IgE in serum, inhibited the activities of EPO in lung, and up-regulated levels of IL-10 and IFN-γ in BALF as well as the percentage of CD4⁺CD25⁺Foxp3⁺ regulatory T cells in spleen.

Conclusion

CPPD can significantly suppress OVA-induced airway inflammation, airway hyperreactivity and Th2 predominant response in mice, showing great therapeutic potential for the treatment of allergic asthma.     

Differential role of YiGanKang decoction in IL-1β induction of IL-1RI and AP-1 in rat hepatic stellate cell

Background/Aim

YiGanKang, a combination of Chinese herbs, has anti-fibrosis effects in chronic liver diseases. The present study tries to demonstrate differential role of YiGanKang Decoction in interleukin-1β (IL-1β) induction of the type I receptor (IL-1RI) and the activator protein 1 (AP-1) in rat hepatic stellate cell (HSC).

Methods

Flow cytometry was used to detect the IL-1RI expression. Electrophoretic mobility shift assays was used to detect AP-1 activity.

Results

IL-1RI expression after IL-1β treatment for 0, 2, 10, 60, and 120 min was 227.08 (13.15), 268.43 (8.93), 442.97 (7.00), 367.66 (14.70), and 261.58 (15.08), respectively. The differences between IL-1RI expression after treatment for 10 and 60 min were significantly higher than the corresponding values in the control (P < 0.01, P < 0.01, respectively); After pretreatment with YiGanKang Decoction, IL-1RI expression induced by IL-1β was not decrease obviously; IL-1β could activate AP-1 in rat HSCs (P < 0.01). Meanwhile YiGanKang Decoction could inhibit activity of AP-1 induced by IL-1β (P < 0.01), and the inhibition rate was 42.71%.

Conclusion

YiGanKang Decoction could not decrease IL-1RI expression, but it could inhibit activity of AP-1 in rat HSCs induced by IL-1β.     

Antiplasmodial activity of the andiroba (Carapa guianensis Aubl., Meliaceae) oil and its limonoid-rich fraction

Ethnopharmacological relevance

From seeds of Carapa guianensis the Amazon native people extracts the andiroba oil, which is traditionally used as febrifuge, anti-malarial, insecticidal and repellant. The non-saponifiable fraction separated from the oil is rich in limonoids, which assigns its pharmacological effects.

Materials and methods

The andiroba oil and its limonoid-rich fraction were submitted to in vitro antiplasmodial bioassay using W₂ and Dd₂ strains of Plasmodium falciparum. The acute toxicity of andiroba oil was evaluated. The limonoid-rich fraction was subjected to fractionation and identified its major constituents.

Results

Andiroba oil and its limonoid-rich fraction inhibited the growth of W₂ clone in 100%, between 24 and 72 h, at concentrations of 8.2 μg/mL and 3.1 μg/mL, respectively. Under the same conditions, the parasitaemia of Dd₂ clone provoked by the andiroba oil showed inhibition of 31% (IC₅₀ >82 μg/mL) with a time-dependent relationship of 24 h and inhibition of 88% (IC₅₀ 8.4 μg/mL) after 72 h, while for the limonoid-rich fraction the inhibition of Dd₂ clone was 56% (IC₅₀ 2.8 μg/mL) at 24 h and 82% (IC₅₀ 0.4 μg/mL) after 72 h. Andiroba oil in acute toxicity test with a fixed dose (LD₅₀ >2000 mg/kg) was not toxic The limonoids identified in the oil were gedunin, 6α-acetoxygedunin, 7-deacetoxy-7-oxogedunin, 7-deacetylgedunin, 1,2-dihydro-3β-hydroxy-7-deacetoxy-7-oxogedunin and andirobin. Gedunin and derivatives has been reputed as anti-malarials.

Conclusion

The results support the traditional use of andiroba oil as antiplasmodial, which additionally proved not to be toxic in bioassays conducted with mice.     

Evaluation of diuretic activity of Amaranthus spinosus Linn. aqueous extract in Wistar rats

Ethnopharmacological relevance

Traditional Siddha medicine literature claims that the Amaranthus spinosus Linn. (family: Amaranthaceae) whole plant possesses diuretic property.

Aim of the study

To evaluate the diuretic potential of Amaranthus spinosus aqueous extract (ASAE) in rats.

Material and methods

Different concentrations of ASAE (200, 500, 1000, 1500 mg/kg), thiazide (10 mg/kg) and vehicle were orally administered to rats (n = 6 animals per group) and their urine output was collected after 24 h. Volume, pH, Na⁺, K⁺ and Cl⁻ concentrations of urine were estimated.

Results

ASAE produced increase in Na⁺, K⁺, Cl⁻ excretion, caused alkalinization of urine, showed strong saluretic activity and carbonic anhydrase inhibition activity. These effects were observed predominantly at 500 mg/kg dose and there was no dose–response relationship.

Conclusion

Our study strongly suggests that the Amaranthus spinosus is acting as a thiazide like diuretic with carbonic anhydrase inhibitory activity which restates the claim as diuretic herb in Siddha medicine.     

Neuroprotective activityof Cymbopogon martinii against cerebral ischemia/reperfusion-induced oxidative stress in rats

Ethnopharmacological relevance

Cymbopogon martinii (Roxb.) Watson (Family: Graminae), commonly known as Palmarosa, is traditionally prescribed for central nervous system (CNS) disorders such as neuralgia, epileptic fits and anorexia. Although the plant possesses diverse pharmacological actions, the neuroprotective action has got little attention.

Aim of the study

The present study evaluated neuroprotective effect of essential oil of Cymbopogon martinii (EOCM) against global cerebral ischemia/reperfusion (I/R)-induced oxidative stress in rats.

Materials and methods

Global ischemic brain damage was induced by bilateral common carotid artery (BCCA) occlusion for 30 min, followed by 60 min reperfusion on Wistar albino rats. The biochemical levels of lipid peroxidation (LPO), superoxide dismutase (SOD), catalase (CAT), total thiols and glutathione (GSH) were estimated and brain coronal sections and histopathological studies were performed.

Results

BCCA occlusion, followed by reperfusion caused varied biochemical/enzymatic alterations viz. increase in LPO and decrease in SOD, CAT, total thiols and GSH. The prior treatment of EOCM (50 mg/kg and 100 mg/kg, p.o. for 10 days) markedly reversed these changes and restored to normal levels as compared to I/R groups. Moreover, brain coronal sections and histopathological studies revealed protection against ischemic brain damage in the EOCM-treated groups.

Conclusion

This study, for the first time, shows potent neuroprotective effect of EOCM against global cerebral I/R-induced oxidative stress in rats, suggesting its therapeutic potential in cerebrovascular diseases (CVD) including stroke.     

Evaluation of anti-tussive activity of Chamaedorea tepejilote

Aim of the study

Evaluate the potential inhibition of cough in a mouse model induced by sulfur dioxide gas of methanol and chloroform extracts of aerial parts of Chamaedorea tepejilote.

Material and methods

The antitussive effect was examined using the Ogyhara method. The extracts and theobromine were orally administered to mice. Each extract was administered to one group (400 mg/Kg) and theobromine (2 mg), and negative control received PVP. The frequency of cough was measured at 60, 90 min after the administration of chloroform extract.

Results

The water extract of C. tepejilote had no effect on the pharmacological model used in this study. The effects of the methanol and chloroform extracts of this plant on sulfur-dioxide-induced cough in experimental animals show activity dose-dependently in the range between 100 to 500 mg/Kg. At doses of 400 mg/kg, the methanol and chloroform extracts inhibited cough by 41.72% and 49.1%, respectively; these results are comparable to the effect produced by the antitussive agent theobromine (53.4% inhibition).

Conclusions

Both extracts exhibited significant antitussive activity, and the effect of the chloroform extract was dose dependent. The antitussive activity of this extract was comparable to that of theobromine. The effect of chloroform extract on the trachea was also tested; it did not relax pre-contractions in guinea pig trachealis induced KCl, carbachol or histamine.     

Anti-urolithiatic effects of Punica granatum in male rats

Ethnopharmacological relevance

The traditional use of Punica granatum has been reported to regulate urine discharge and controls the burning sensation of urine.

Materials and methods

Animals model of calcium oxalate urolithiasis was developed in male rats by adding ethylene glycol 0.75% in drinking water. The Punica granatum chloroform extract (PGCE) and Punica grantum methanol extract (PGME) orally at 100, 200 and 400 mg/kg, respectively, were administered along with ethylene glycol for 28 days. On 28 day, 24 h urine was collected from individual rats and used for estimation of urine calcium, phosphate and oxalate. The serum creatinine, urea and uric acid levels were estimated in each animal. The kidney homogenate was used for the estimation of renal oxalate contents. The paraffin kidney sections were prepared to observe the CaOx deposits.

Results

The ethylene glycol control (Gr.-II) had significant (P < 0.001 vs. normal) increase in levels of urine oxalate, calcium and phosphate, serum creatinine, urea and uric acid and renal tissues oxalates, as compared to normal (Gr.-I). The paraffin kidney sections show significant histopathological changes. The treatment of PGCE and PGME at 100, 200 and 400 mg/kg doses, significantly (P < 0.001 vs. control) decreased the urine oxalate, calcium and phosphate, renal tissue oxalates and serum creatinine, urea and uric acid, in EG induced urolithiasis after 28 days.

Conclusions

The PGCE and PGME at the doses of 400 mg/kg, found to be more effective in decreasing the urolithiasis and regeneration of renal tissues in male rats.     

Antinociceptive effectiveness of triterpenes from rosemary in visceral nociception

Ethnopharmacological relevance

Rosemary is a species used worldwide as a common spice, but also in folk medicine for their therapeutic properties against abdominal pain. The rationale of this study was to examine the involvement of triterpenes and to compare their effectiveness in the antinociceptive effect of an ethanol extract of Rosmarinus officinalis L. (Lamiaceae).

Material and methods

Fractionation and HPLC analyses allowed the identification of a mixture of micromeric (121 mg/g), oleanolic (64 mg/g) and ursolic (83 mg/g) acids as partial antinociceptive responsible in an ethyl acetate fraction of R. officinalis by using the acetic acid-induced abdominal constrictions model in mice.

Results

These triterpenes individually evaluated produced a significant and dose-dependent antinociceptive response with similar potency as follows: ED₅₀=1.1 mg/kg (0.9–1.3 mg/kg), 2.1 mg/kg (1.6–2.6 mg/kg) and 1.6 mg/kg (1.1–2.1 mg/kg), respectively, by using the intraperitoneal (i.p.) route of administration in mice. Their maximal antinociceptive efficacy resembled that produced by ketorolac (10 mg/kg, i.p.), a common clinic analgesic.

Conclusion

Our results provide evidence that these triterpenes participate in the antinociceptive activity of R. officinalis. In addition, each individual triterpene showed a similar potency to that observed with ketorolac, a non-steroidal anti-inflammatory drug, in this experimental model.     

Anti-diabetic activity of extract from Persea americana Mill. leaf via the activation of protein kinase B (PKB/Akt) in streptozotocin-induced diabetic rats

Ethnopharmacological relevance

The leaves of Persea americana Mill. (Lauraceae) have been popularly used in the treatment of diabetes in countries in Latin America and Africa.

Aim of the study

To investigate the hypoglycaemic properties and to determine the molecular mechanism by which the hydroalcoholic extract of the leaves of Persea americana reduce blood glucose levels in streptozotocin (STZ)-induced diabetes in rats via the enzymatic pathway of protein kinase B (PKB/Akt).

Methods

The hydroalcoholic extract of the leaves of Persea americana (0.15 and 0.3 g/kg/day), vehicle and metformin (0.5 g/kg/day) were administered orally to STZ-diabetic rats (n = 7/group) for 4 weeks. Changes in body weight, food and water intake, fasting glucose levels and oral glucose tolerance were evaluated. Phosphorylation and the expression of PKB in the liver and soleus muscle were determined by Western blot.

Results

The hydroalcoholic extract of the leaves of Persea americana reduced blood glucose levels and improved the metabolic state of the animals. Additionally, PKB activation was observed in the liver and skeletal muscle of treated rats when compared with untreated rats.

Conclusion

The results indicate that the hydroalcoholic extract of the leaves of Persea americana has anti-diabetic properties and possibly acts to regulate glucose uptake in liver and muscles by way of PKB/Akt activation, restoring the intracellular energy balance.     

Scorpio and Scolopendra attenuate inflammation and articular damage in rats with collagen-induced arthritis

Ethnopharmacological relevance

Scorpio and Scolopendra (SS) are two traditional Chinese medicines, which are generally used to treat rheumatoid arthritis (RA) in China. However, the mechanism is so far unclear. The purpose of this study was to explore the effects and mechanisms of SS in attenuating inflammation and joint injury in collagen-induced arthritis in rats.

Materials and methods

RA was induced in Wistar rats by injection of collagen, meanwhile, the rats were administrated daily either SS (0.4 g/kg, 0.2 g/kg, and 0.1 g/kg) or vehicle (physiological saline) for 42 days. The therapeutic effect of SS on RA was evaluated by pathological methods. T lymphocyte subsets and anti-collagen type II (CII) antibody were tested in peripheral blood. Tumor necrosis factor alpha (TNF-α), interleukin-1β (IL-1β), interleukin-4 (IL-4) and interleukin-10 (IL-10) were assessed in tissue homogenate of fresh joints.

Results

The inflammation and articular damage in SS powder-treated rats were attenuated significantly. In addition, SS powder was revealed to modulate the equilibrium of T lymphocyte subsets, down-regulate TNF-α and IL-1β, up-regulate IL-4 and IL-10, and significantly suppress the level of anti-CII antibody.

Conclusions

Scorpio and Scolopendra, when used as a combination, reveal desirable effect for treatment of rheumatoid arthritis, and this beneficial effect may be accomplished through normalization of T lymphocyte subsets and the balance of Th1/Th2 cytokines.     

Hancornia speciosa: indications of gastroprotective, healing and anti-Helicobacter pylori actions

Ethnopharmacological relevance

Mangaba (Hancornia speciosa Gomez) is a medicinal plant frequently cited in ethnopharmacological inventories of the central region of Brazil against gastrointestinal disorders such as diarrhoea, ulcer, gastritis and stomachache.

Aim of the study

The hydroalcoholic extract (HE) and infusion (BI) of Hancornia speciosa bark were investigated for their ability to prevent and heal rodent gastric ulcer.

Materials and methods

The preventive and healing action of both preparations of Hancornia speciosa were evaluated in experimental models in rodents that simulated this disease in human gastric mucosa.

Results

BI did not exert gastroprotective effect, in contrast to HE (500 mg/kg, p.o.) that decreased (p < 0.05) the severity of gastric damage induced by HCl/ethanol (52%), indomethacin/bethanechol (51%), stress (52%) or pylorus ligature experiments (54%). HE increased (p < 0.05) the pH and decreased acid output of gastric juice. This extract promoted increase of mucus amount (3.62 mg/wt. tissue vs. 5.81 mg/wt. tissue), healing action (67%) and displayed anti-Helicobacter pylori effect.

Conclusions

The antiulcer action of Hancornia speciosa resulted in increase of gastric mucus formation and antioxidant properties of polymeric proanthocyanidins present in the bark composition of this medicinal plant.     

The effects of Polygonum cuspidatum extract on wound healing in rats

Aim of the study

Polygonum cuspidatum has long been used as a traditional medicine inducing wound healing. In this study, the extract from the Chinese medicinal herb Polygonum cuspidatum was investigated on its wound healing activity, in order to obtain an accurate elucidation of its traditional use value.

Materials and methods

After creating wound healing model on the back of rats, the extract from the Chinese medicinal herb Polygonum cuspidatum was applied. Wound healing rates were calculated at 3, 7, 14, and 21 days after the wounding, and tissues were harvested at 1, 3, 7, 14 and 21 days for histological and immunohistochemistry analysis. The stages of wound granulation tissues were evaluated histopathologically. The expression of TGF-β1 was determined by immunohistochemically.

Results

Wound healing rates were significantly higher at 3, 7, 14 and 21 days in the extract group than in the control (p < 0.05). Histological results showed more well-organized bands of collagen, more fibroblasts and hair follicle and less inflammatory cells in the extract group. The immunohistochemical results revealed that TGF-β1 increased in the extract group on day 1, 3 and 7 post-wounding (p < 0.05).

Conclusion

The present study has shown that the extract from the Chinese medicinal herb Polygonum cuspidatum possesses wound healing activity, and thus provided the evidence for its traditional use value.     

Isolation of gentiopicroside from Gentianae Radix and its pharmacokinetics on liver ischemia/reperfusion rats

Ethnopharmacological relevance

Gentiopicroside (GPS) is a secoiridoid glucoside isolated from the ethanol extract of Gentianae Radix with a content of 13%, which has been used for centuries in Chinese as a digestive aid.

Aim of the study

This study investigates the pharmacokinetics of GPS and its metabolic pathway for the liver ischemia/reperfusion (I/R) in rats.

Materials and methods

The experimental animals were anesthetized intraperitoneally (i.p.) with a mixture of urethane (1.0 g/kg) and α-chloralose (0.1 g/kg). A midline laparatomy was performed and the liver hilum was gently exposed. All structures in the portal triad (hepatic artery, portal vein, and bile duct) to the left and median liver lobes were occluded with silk thread for 30 min. Ischemia was followed by a sudden reperfusion after removing the occluding threads. After 60 min reperfusion, the rats received a single intravenous 5 mg/kg dose of GPS.

Results

The area under concentration curve (AUC) was significantly increased; however, the clearance (Cl) was significantly decreased in the liver I/R rats. Furthermore, after pretreated with SKF-525A (50 mg/kg, i.p.), a cytochrome P450 (CYP) inhibitor, AUC, elimination half-life (t_1/2) and the mean residence time (MRT) of GPS in rat blood were significantly increased, suggesting that CYP was involved in the metabolism of GPS. For the group without liver I/R, GPS was administered at doses of 5 mg/kg and 100 mg/kg intravenously and orally, respectively. The pharmacokinetic results indicated that the AUC was 565 ± 95.1 and 1163 ± 273 min μg/mL and the t_1/2 of GPS was 71 ± 9 and 106 ± 17 min after intravenous and oral administration, respectively. The oral bioavailability of GPS was 10.3 ± 2.4% in the rats.

Conclusions

The status of I/R might prolong the disposition of GPS, and the plasma concentration of GPS in the liver I/R injury rats was significantly increased. The increased body exposure of GPS in the treatment of liver I/R may result from the decreased metabolism of GPS mediated by CYP in the liver.     

Gastroprotective activities of Turnera diffusa Willd. ex Schult. revisited: Role of arbutin

Ethnopharmacological relevance

Turnera diffusa Willd. ex Schult. has been used for the treatment of several human disorders including peptic ulcer.

Objectives of the study

The current study is an attempt to evaluate the anti-ulcerogenic activities of arbutin, a major constituent of Turnera diffusa on two ulcer models. The possible involvement of lipid peroxidation, nitric oxide, IL-6, IL-10, TNF-α and mucus barrier mechanism has been investigated.

Materials and methods

Effects of arbutin on ulcer index, gastric juice acidity, mucus content and histochemistry, gross and histological gastric lesions, nitric oxide, cytokines levels (IL-6, IL-10 and TNF-α), and thiobarbituric acid reactive substances (TBARS), were evaluated in aspirin or ethanol-induced ulcer in vivo. Acute toxicity of arbutin was also examined in rodent model. MTT assay was used to assess the cytotoxicity of the compound on normal liver cells (WRL-68).

Results

Pre-treatment with arbutin or omeprazole protected the gastric mucosa as seen by reduction in ulcer area and mucosal content, reduced or absence of edema, inflammation and leucocytes infiltration on both models. Arbutin significantly (P < 0.05) lowered the elevated TBARS level into gasteric homogenate. Arbutin did not produce significant inhibition of NO. This natural compound has modulated the levels of interleukin-6, interleukin-10 and TNF-α. No in vitro or in vivo toxicities for arbutin were observed.

Conclusion

Thus it can be concluded that Turnera diffusa possesses anti-ulcer activity, which could be attributed to lipid peroxidation inhibitory, immuno modulatory and anti-oxidant mechanisms of arbutin but not to the intervention with nitric oxide inflammation pathway.     

Double directional adjusting estrogenic effect of naringin from Rhizoma drynariae (Gusuibu)

Ethnopharmacological relevance

Chinese traditional medicine Rhizoma drynariae (Gusuibu) is widely used for clinically treating osteoporosis and bone non-union. Naringin and its active metabolite naringenin are the main active ingredients of Rhizoma drynariae total flavonoids.

Aim of the study

The purpose of this paper is to confirm estrogenic and anti-estrogenic activity of naringin and naringenin, and provide the basic data to further study for the dose-effect relationship and the mechanism for Rhizoma drynariae in treatment of osteoporosis and other estrogen deficiency-related diseases.

Materials and methods

Naringin was extracted from Rhizoma drynariae. Naringin and its metabolin naringenin were tested estrogenic and anti-estrogenic activities through the experiment of cell proliferation and uterus weight gain in mice. Their estrogen-receptor binding abilities were tested by yeast two-hybrid experiment and nuclear receptor cofactor assays (RCAS) experiment, and their possible binding sites for ERβ were performed by computer aided molecular docking technology.

Results

Naringin and naringenin showed significant effects on the proliferation of estrogen-sensitive ER(+) MCF-7 cells in the absence of estrogen. Induction increased proliferation as the drug concentration, and the strongest proliferation appeared at a concentration of 8.6 × 10⁻⁵ M. When estradiol (10⁻¹⁰ M) and the different concentrations of naringin or naringenin were treated at the same time, naringin and naringenin could result in antagonistic effects on estradiol-induced MCF-7 cell proliferation, but they did not significantly affect proliferation of estrogen-insensitive ER(−) MDA-MB-231 cells. Naringin and naringenin exhibited higher binding capacity to estrogen receptor β (ERβ) than estrogen receptor α (ERα) in yeast two-hybrid experiments and nuclear receptor cofactor assays (RCAS) experiment. Docking simulation between naringin/naringenin and ERβ were performed, and the corresponding binding free energies of naringin-receptor and naringenin-receptor docked complexes were −7.95 and −10.45 kcal/mol. Hydrogen bonds were found between naringin and the amino acid residues Lys304 and His308. The oxygen atom (O11) of naringenin formed hydrogen bond to Arg346, and there may be hydrophobic space interactions between phenyl group (C13-C18) of naringenin and the amino acid residues Leu298, Met336, Met340, Phe356, Ile376 and Leu380.

Conclusions

Naringin and naringenin revealed a double directional adjusting function of estrogenic and anti-estrogenic activities. Both of them showed estrogenic agonist activity at low concentration or lack of endogenous estrogen. On the other hand, they also acted as estrogenic antagonists at high concentrations or too much endogenous estrogen. They produced estrogenic and anti-estrogenic effects primarily through selectively binding with ERβ, which could prevent and treat osteoporosis with the mechanism of estrogenic receptor agitation. This paper confirmed the estrogenic and anti-estrogenic activity of naringin and naringenin, and further studies were still essential to study their dose-effect relationship and the anti-osteoporosis mechanism for Rhizoma drynariae in the treatment of osteoporosis and other estrogen deficiency-related diseases.     

Vitexin and isovitexin from the Leaves of Ficus deltoidea with in-vivo α-glucosidase inhibition

Ethnopharmacological relevance

The leaves of Ficus deltoidea are used as a traditional medicine by diabetes patients in Malaysia.

Aim of the study

The objective of the study is to identify and evaluate bioactive constituents with in vivo α-glucosidase inhibition.

Materials and Methods

The partitioned extracts, subfractions and pure bioactive constituents were subjected to α-glucosidase inhibition assay. The identified bioactive constituents were administered orally to sucrose loaded normoglycemic mice and induced diabetic rats. The postprandial blood glucose levels were monitored at 30 min interval. Acute toxicity was evaluated in both normoglycemic mice and induced diabetic rats.

Results

Bioactivity guided fractionation led to the isolation of both vitexin (1) and isovitexin (2). Oral administration of 1 mg/kg of either vitexin (1) or isovitexin (2) significantly (p<0.05) reduced the postprandial blood glucose level in sucrose loaded normoglycemic mice at 30 min. The percentage of postprandial blood glucose reduction was highest in sucrose loaded induced diabetic rats administered orally with 200 mg/kg of vitexin (1) or 100 mg/kg of isovitexin (2). Both vitexin (1) and isovitexin (2) did not exert any signs of toxicity at the highest dose of 2 g/kg administered orally to normoglycemic mice and induced diabetic rats.

Conclusion

Both the C-glycosyl bioflavonoids, namely, vitexin (1) and isovitexin (2) exhibited in vivo α-glucosidase inhibition.     

Immunomodulatory effect of Antrodia camphorata mycelia and culture filtrate

Aim of the study

Antrodia camphorata, a precious folkloric medicinal mushroom, has been used to treat tumorigenic diseases in Taiwan. This study was to investigate the innate immunity augmentation effects of different fractions prepared from hot water extracts of submerged cultured Antrodia camphorata (AC).

Materials and methods

The cytokine induction potency of AC fraction in diluted peripheral blood culture was measured by ELISA. The effects of AC fraction on phagocytic activity and CD11b expression were measured by the ingestion of FITC-labeled Escherichia coli and by labeling with PE-labeled CD11b monoclonal antibody, respectively, using flow cytometry. The molecular mass of hot water-soluble polysaccharides and content of adenosine in AC fraction were determined by gel permeation chromatography (GPC) and HPLC, respectively.

Results

The mycelia fraction, Fr. M II, and culture filtrate fractions, Fr. E II and Fr. E III, showed the strongest TNF-α and IL-6 induction effect as a function of their concentration. These fractions (20 μg/ml) also showed marked activity in enhancing phagocytosis in human polymorphonuclear neutrophils (PMN) and monocytes. In parallel, the expression of CD11b, an early marker of PMN activation, was also up-regulated dose-dependently. Composition analysis suggested that immunomodulatory effect of mycelia is mainly attributed to the 10–20 kDa polysaccharides and adenosine.

Conclusions

These results provide evidences that Antrodia camphorata can modulate innate immunity and may serve as an adjuvant for tumor treatment.     

Anti-inflammatory effect of triterpene 3β, 6β, 16β-trihydroxylup-20(29)-ene obtained from Combretum leprosum Mart & Eich in mice

Ethnopharmacological relevance

The 3β, 6β, 16β-trihydroxylup-20(29)-ene (TTHL) is a pentacyclic triterpene obtained from a medicinal plant named Combretum leprosum. In folk medicine, this plant is used to treat several diseases associated with inflammation and pain. We previously demonstrated that TTHL presents a significant antinociceptive effect, suggesting the involvement of the glutamatergic system.

Aim of the study

This study was designed to investigate the effect of TTHL on nociception and vascular permeability induced by acetic acid. We also evaluated the effect of TTHL on carrageenan-induced peritonitis and the levels of cytokines (interleukin 1-β [IL-1β], tumor necrosis factor α [TNF-α] and interleukin 10 [IL-10]) on peritoneal fluid.

Materials and methods

TTHL was administered orally by intra-gastric gavage (i.g.) 60 min prior to experimentation. Abdominal contractions and vascular permeability were induced by an intraperitoneal (i.p.) injection of acetic acid (0.6%). We also investigated whether TTHL decreases carrageenan-induced peritonitis (750 μg/cavity) by measuring leukocyte migration and vascular permeability. In addition, we evaluated the effects of TTHL on TNF-α, IL-1β and IL-10 release induced by carrageenan on peritoneal fluid. The levels of these cytokines were measured by ELISA.

Results

TTHL (0.01–10 mg/kg) administered by intra-gastric (i.g.) gavage inhibited (69±3%) acetic acid-induced abdominal constrictions, with an ID₅₀ of 0.15 (0.03–0.8) mg/kg. TTHL (10 mg/kg) also reduced the leukocyte infiltration induced by acetic acid, with an inhibition of 59±9 but had no effect on abdominal vascular permeability. In addition, indomethacin (10 mg/kg, i.p.) reduced the nociceptive behavior (92±1%), total leukocyte migration (29±3%) and capillary permeability (71±3%) induced by acetic acid. While the glucocorticoid dexamethasone (2 mg/kg, s.c.) reduced partially but significantly the nociception (31±1%), besides to promote a marked reduction on total leukocyte migration (60±2%) to the peritoneal cavity caused by acetic acid. In a model of peritonitis induced by carrageenan, TTHL also reduced total leukocyte migration, mainly neutrophils (inhibition of 84±3% and 85±2% at 30 mg/kg and 100 mg/kg, respectively). Likewise, dexamethasone (0.5 mg/kg, i.p.) resulted in an inhibition of 93±3%. Nevertheless, carrageenan-induced abdominal vascular permeability was reduced by dexamethasone but was not altered by TTHL. Furthermore, dexamethasone and TTHL significantly reduced the TNF-α and IL-1β levels in peritoneal fluid, whereas the IL-10 levels were unchanged.

Conclusions

Altogether, our data confirm the antinociceptive effect of TTHL and demonstrate its effect in inflammatory animal models, providing novel data about this compound, which could be useful as an anti-inflammatory drug.     

Immunosuppressive effects of an ethyl acetate extract from Urtica dentata Hand on skin allograft rejection

Aim of the study

To investigate the immunosuppressive effects of HPLC qualitied ethyl acetate extract (EAE) from Urtica dentate Hand on skin allograft rejection in a murine model.

Materials and methods

Allo-skin transplantation model was established by placing skin allograft of C57BL/6 mice in the wound bed which was on the back of Balb/c mice. We used FACS to study the effects of EAE on dendritic cells (DCs) maturation and CD4⁺CD25⁺T regulatory cells (Tregs) differentiation. We also studied spleen lymphocyte proliferation and T-bet gene expression in DCs. Concentration of Th1/Th2 cytokines was monitored as markers of Th1/Th2 responses by ELISA.

Results

A significant prolongation of skin allografts survival was observed as a dose-dependent manner in the animals treated with EAE. By FACS, we found that treatment with EAE (200 mg kg⁻¹) resulted in an immature statement of DCs and stimulated the differentiation of CD4⁺CD25⁺Tregs. Additionally, the expression of T-bet gene and the proliferation of spleen lymphocytes were efficiently abated in EAE treated mice. Comparing to the model control, EAE-treated recipients showed a significant down-regulation (P < 0.01) of Th1 cytokines (IL-2, IFN-γ) and an obviously increase (P < 0.01) of Th2 cytokine (IL-10) in the serum, which presented in a dose-related way.

Conclusions

The anti-allograft rejection effect of EAE by enhancing CD4⁺CD25⁺Tregs differentiation and sustaining DCs immaturation makes EAE to be a possible choice for treating autoimmune diseases in a way of inducing a stable immunological tolerance state.