Antihyperlipidemic effect of the methanolic extract from Lagenaria siceraria Stand. fruit in hyperlipidemic rats

Ethnopharmacological relevance

Lagenaria siceraria Stand. (Cucurbitaceae) fruits have been used, traditionally, in the treatment of hyperlipidemia and atherosclerotic impasse and considered as cardioprotective and cardiotonic drug.

Aim of the study

The present work was undertaken to investigate the effects of methanolic extract from Lagenaria siceraria in experimentally induced hyperlipidemia in rats.

Materials and methods

Methanolic extract of Lagenaria siceraria fruits (LSFE) (100, 200 and 300 mg/kg; p.o.) was administered to the high fat-diet-induced hyperlipidemic rats for 30 days to evaluate its antihyperlipidemic activity. Atorvastatin (10 mg/kg; p.o.) was used as a standard drug.

Results

At the 30th day, most significant reduction in lipid levels in the LSFE treated rats as compared to the rats fed with high-fat diet at the 0th day were: total cholesterol 290.14 ± 18.42 mg/dl vs. 228.58 ± 16.38 mg/dl, low-density lipoprotein cholesterol 195.14 ± 8.86 mg/dl vs. 120.57 ± 8.11 mg/dl, triglyceride 232.41 ± 15.22 mg/dl vs. 181.79 ± 15.68 mg/dl, very low-density lipoprotein cholesterol 46.48 ± 3.04 mg/dl vs. 36.35 ± 3.13 mg/dl (P < 0.0001). Conversely, high-density lipoprotein cholesterol levels were significantly (P < 0.0001) increased from 48.52 ± 6.52 to 71.66 ± 5.14 mg/dl. The increase in weight in rats administered with LSFE was less when compared to rats fed with high-fat diet. Moreover, LSFE also exhibited significant increase in excretion of bile acids.

Conclusion

The results demonstrate that the LSFE has a definite antihyperlipidemic potential. There is also a valid scientific basis for consuming it in the treatment of coronary artery diseases in India.     

Effect of American ginseng (Panax quinquefolius L.) on arterial stiffness in subjects with type-2 diabetes and concomitant hypertension

Ethnopharmacological relevance

Substantial pre-clinical and some clinical data are available showing that Asian ginseng (Panax ginseng C.A. Meyer) varieties or its particular ginsenosides exert a vasodilatating effect, thus may modulate vascular function. However, the clinical evidence for American ginseng (Panax quinquefolius L.) is scarce. Therefore, this study evaluates the effect of American ginseng (AG) on arterial stiffness, as measured by augmentation index (AI), and blood pressure (BP), in type 2 diabetes patients with concomitant hypertension.

Materials and methods

Using a double-blind, placebo-controlled, parallel design, each participant was randomized to either the selected AG extract or placebo at daily dose of 3 g for 12 weeks as an adjunct to their usual antihypertensive and anti-diabetic therapy (diet and/or medications). AI and BP were measured by applanation tonometry at baseline and after 12 weeks of treatment.

Results

A total of 64 individuals with well-controlled essential hypertension and type 2 diabetes (gender: 22 M:42 F, age:63±9.3 years, BP: 145±10.8/84±8.0 mmHg, HbA1c: 7.0±1.3%, fasting blood glucose (FBG): 8.1±2.3 mmol/L) completed the study. Compared to placebo, 3 g of AG significantly lowered radial AI by 5.3% (P=0.041) and systolic BP by 11.7% (P<0.001) at 12 weeks. No effect was observed with diastolic BP.

Conclusions

Addition of AG extract to conventional therapy in diabetes with concomitant hypertension improved arterial stiffness and attenuated systolic BP, thus warrants further investigation on long-term endothelial parameters before recommended as an adjunct treatment.     

Effects of Campomanesia xanthocarpa on biochemical,hematological and oxidative stress parameters in hypercholesterolemic patients

Ethnopharmacological relevance

In Southern Brazil, the plant Campomanesia xanthocarpa Berg. (Myrtaceae), popularly known as “guavirova”, has been empirically used for its potential effect in reducing blood cholesterol levels.

Aim of the study

Since there are no scientific data confirming its popular use, the aim of the present study was to investigate the effect of Campomanesia xanthocarpa on biochemical, hematological, anthropometrical and oxidative stress parameters in hypercholesterolemic patients.

Materials and methods

Thirty three patients were selected according to total cholesterol (TC) levels: 200–240 mg/dL, undesirable level (UL), and >240 mg/dL, hypercholesterolemic level (HL). UL or HL patients were randomly divided into control group (CG), which received placebo capsules, and experimental group 250 (EG 250) or 500 (EG 500), which received either 250 or 500 mg of encapsulated Campomanesia xanthocarpa. All groups received a cholesterol restriction diet and capsules once a day. The biochemical (TC, triglycerides, HDL, LDL and VLDL), hematological (hematocrit and hemoglobin), anthropometrical (weight and abdominal circumference) and oxidative stress (protein carbonyl) parameters were measured before, 45 and 90 days after the treatment started.

Results

There was no alteration on biochemical, hematological, anthropometric or oxidative stress parameters in UL patients of all groups. However, a significant decrease in TC and LDL levels was observed in HL patients from EG 500 group (reduction of 28 ± 3% and 45 ± 4% to levels before treatment) in relation to CG group patients (reduction of 12 ± 2% and 29 ± 4%). Moreover, a significant reduction in oxidative stress was observed in HL patients of EG 250 (51 ± 12%) and EG 500 groups (34 ± 18%) when compared to levels before treatment. A positive correlation between plasma oxidative stress PC and TC levels was observed. Finally, we found that Campomanesia xanthocarpa extract possesses anti-oxidant properties and 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitory activity in vitro.

Conclusion

Confirming its popular use, the treatment with Campomanesia xanthocarpa encapsulated reduced blood TC and LDL levels in hypercholesterolemic patients.     

Pharmacokinetic properties of hydroxysafflor yellow A in healthy Chinese female volunteers

Ethnopharmacological relevance

Hydroxysafflor yellow A (HSYA) was isolated from the dried flower of Carthamus tinctorius L. which was extensively used in traditional Chinese medicine to treat diseases due to blood stasis. However, there have been few detailed pharmacokinetic studies about HSYA on human beings.

Aim of the study

The aim was to investigate the pharmacokinetic characteristics of HSYA in healthy Chinese female volunteers.

Materials and methods

The volunteers were given intravenous infusion of single doses of safflor yellow injection (containing HSYA 35, 70 and 140 mg) in separate trial periods with 1 week washout period. The concentration levels of HSYA in plasma were determined with HPLC. Various pharmacokinetic parameters were estimated from the plasma concentration versus time data using non-compartmental methods.

Results

The C_max values were 2.02 ± 0.18, 7.47 ± 0.67 and 14.48 ± 4.71 μg/mL after the administration of single doses of 35, 70, and 140 mg of HSYA, respectively. The corresponding values of AUC_0–15h were 6.57 ± 1.20, 25.90 ± 4.62 and 48.47 ± 12.11 μg/(mL h⁻¹), and the values of t_1/2 were 3.21 ± 1.26, 3.33 ± 0.68 and 2.98 ± 0.09 h. The Student–Newman–Keuls test results showed that C_max and AUC_0–15h were both linearly related to dose.

Conclusions

In this study, the pharmacokinetic properties of HSYA are based on first-order kinetics over the dose range tested.     

In vitro antimicrobial activity of Caesalpinia ferrea Martius fruits against oral pathogens

Aim

In the Amazon region of Brazil, the fruits of Caesalpinia ferrea Martius (Brazilian ironwood) are widely used as an antimicrobial and healing medicine in many situations including oral infections. This study aimed to evaluate the antimicrobial activity of Caesalpinia ferrea Martius fruit extract against oral pathogens.

Materials and methods

Polyphenols estimation and spectral analysis (¹H NMR) of the methanol extract were carried out. The microorganisms Candida albicans, Streptococcus mutans, Streptococcus salivarius, Streptococcus oralis and Lactobacillus casei were tested using the microdilution method for planktonic cells (MIC) and a multispecies biofilm model. Chlorhexidine was used as positive control.

Results

Polyphenols in the extract were estimated at 7.3% and ¹H NMR analysis revealed hydroxy phenols and methoxilated compounds. MIC values for Candida albicans, Streptococcus mutans, Streptococcus salivarius, Streptococcus oralis and Lactobacillus casei were 25.0, 40.0, 66.0, 100.0, 66.0 μg/mL, respectively. For the biofilm assay, chlorhexidine and plant extract showed no growth at 10⁻⁴ and 10⁻⁵ microbial dilution, respectively. At 10⁻⁴ and 10⁻⁵ the growth values (mean ± SD) of the negative controls (DMSO and saline solution) for Streptococcus mutans, Streptococcus sp. and Candida albicans were 8.1 ± 0.7, 7.0 ± 0.6 and 5.9 ± 0.9 × 10⁶ CFU, respectively.

Conclusion

Caesalpinia ferrea fruit extract can inhibit in vitro growth of oral pathogens in planktonic and biofilm models supporting its use for oral infections.     

Oral bioavailability and gender-related pharmacokinetics of celastrol following administration of pure celastrol and its related tablets in rats

Ethnopharmacological relevance

Celastrol is a natural compound extracted from the traditional Chinese medicinal herb, Thunder God Vine (TGV). Owing to its potential anti-inflammatory and antitumor effects, celastrol has been considered as a promising candidate for drug development.

Aim of the study

To establish a sensitive LC–MS/MS method to investigate the pharmacokinetic properties of celastrol in rats. Key pharmacokinetic issues of celastrol including oral bioavailability, comparative pharmacokinetics between pure compound and tablet preparation, as well as gender-related pharmacokinetic difference are to be addressed for the first time.

Materials and methods

Sprague–Dawley rats were administrated an intravenous dose (100 μg kg⁻¹) of pure celastrol and an oral dose (1000 μg kg⁻¹) of pure celastrol and TGV tablets (corresponding to 534 μg kg⁻¹ of celastrol), respectively. At different time points, the concentration of celastrol in rat plasma was determined by a sensitive and well-validated LC–MS/MS method. Main pharmacokinetic parameters including area under the plasma concentration–time curve (AUC), maximal plasma concentration (Cmax), the time for maximal concentration (Tmax) and mean residence time (MRT) were estimated by Drug and Statistic1.0 pharmacokinetic software (Chinese Pharmacological Association, Anhui, PR China). Statistical analysis was performed using two one-side t test with p-values less than 0.05 as the level of significance.

Results

The standard curve of celastrol showed good linearity in the concentration range of 0.11∼54.3 ng mL⁻¹ in our current method, with acceptable selectivity, precision, recovery, and stability. The oral absolute bioavailability of celastrol significantly increased from 17.06% for pure celastrol to 94.19% for TGV tablets containing equivalent celastrol. After oral administration of TGV tablets, the Cmax and AUC values of celastrol in female rats were (32.03±8.41) μg L⁻¹ and (379.49±118.19) μg h L⁻¹, which were significantly higher (p<0.01) than that in males with the values of (14.31±7.33) μg L⁻¹ and (188.17±92.33) μg h L⁻¹.

Conclusion

Celastrol administered orally in the rat was poorly absorbed into the systemic circulation. However, the poor absorption of celastrol could be greatly improved when celastrol-containing TGV tablets orally administered, and thereby the oral bioavailability of celastrol was significantly increased. As for gender difference, female rats showed significantly better absorption of celastrol than males.     

α-Glucosidase inhibitory activity of selected Philippine plants

Ethnopharmacological relevance

Antidesma bunius Spreng. (Phyllantaceae), Averrhoa bilimbi L. (Oxalidaceae), Biophytum sensitivum (L.) DC. (Oxalidaceae), Ceriops tagal (Perr.) C.B. Rob. (Rhizophoraceae), Kyllinga monocephala Rottb. (Cyperaceae), and Rhizophora mucronata Lam. (Rhizophoraceae) are used as remedies to control diabetes. In the present study, these plants were screened for their potential α-glucosidase inhibitory activity.

Materials and methods

The 80% aqueous ethanolic extracts were screened for their α-glucosidase enzyme inhibitory activity using yeast alpha glucosidase enzyme.

Results

Except for A. bilimbi with IC₅₀ at 519.86±3.07, all manifested a significant enzyme inhibitory activity. R. mucronata manifested the highest activity with IC₅₀ at 0.08±1.82 μg mL⁻¹, followed by C. tagal with IC₅₀ at 0.85±1.46 μg mL⁻¹ and B. sensitivum with IC₅₀ at 2.24±1.58 μg mL⁻¹.

Conclusion

This is the first report on the α-glucosidase inhibitory effect of the six Philippine plants; thus, partly defining the mechanism on why these medicinal plants possess antidiabetic properties.     

Aqueous ethanol extract of the fruit of Xylopia aethiopica (Annonaceae) exhibits anti-anaphylactic and anti-inflammatory actions in mice

Ethnopharmacological relevance

Xylopia aethiopica has been traditionally used in the form of the dried fruit decoction to treat bronchitis, asthma, arthritis and rheumatism in Ghana, Nigeria and Cameroon. Aim of the study is to evaluate the anti-anaphylactic and anti-inflammatory effects of a 70% aqueous ethanol extract of the fruits of Xylopia aethiopica.

Materials and methods

Systemic anaphylaxis was induced by the injection of either compound 48/80 or lipopolysaccharide, LPS and survival rates of mice monitored for 1 h or 7 days respectively while IgE-mediated anaphylaxis in a local allergic reaction was studied in the pinnal inflammation model in mice. Clonidine-induced catalepsy in mice was used to evaluate the indirect antihistamine effect of Xylopia aethiopica, XAE. The effects of XAE assessed on the maximal and total oedema responses in the carrageenan-induced paw oedema in mice was used to evaluate the anti-inflammatory action of the extract.

Results

Administered at 30, 100, 300 and 1000 mg kg⁻¹ p.o., XAE dose dependently suppressed compound 48/80-induced mouse systemic anaphylactic shock and offered 63% protection to mice against LPS-induced endotoxic shock at a dose of 300 mg kg⁻¹. In addition, the extract (30–300 mg kg⁻¹) in a dose dependent manner significantly inhibited by 23–62% the mouse pinnal inflammation. Clonidine-induced catalepsy in mice was significantly suppressed in a dose and time dependent manner when administered both prophylactically and therapeutically. In the same doses, when administered before the induction of the mouse carrageenan-induced paw oedema, the mean maximal swelling attained during 6 h was reduced to 41.02±6.94%, 35.61±4.30%, and 29.09±4.90% of the inflamed control response respectively and total paw swellings induced over the 6 h were also dose-dependently and significantly suppressed to 74.84±14.84%, 63.95±9.37%, and 48.13±10.90% of the inflamed control response respectively. Administered after the induction of the carrageenan paw oedema the mean maximal swelling attained during 6 h was suppressed to 49.84±3.95%, 43.62±1.01%, and 35.97±1.34% of the inflamed control response respectively while the total paw swellings induced over the 6 h were also dose-dependently and significantly suppressed at 100 and 300 mg kg⁻¹ to 72.39±4.38% and 60.81±3.25% of the inflamed control response respectively.

Conclusion

These findings suggest that XAE inhibits mast cell-dependent immediate allergic reactions and exhibit anti-inflammatory actions through the inhibition of histamine release from mast cells via stabilizing the cell membrane. Our results contribute towards validation of the traditional use of Xylopia aethiopica in the treatment of bronchitis, asthma, arthritis and rheumatism.     

The effect of ligustrazine on L-type calcium current,calcium transient and contractility in rabbit ventricular myocytes

Ethnopharmacological relevance

Ligustrazine, the biologically active ingredient isolated from a popular Chinese medicinal plant, Ligusticum chuanxiong Hort. (Umbelliferae), has been used effectively to treat ischemic heart diseases, cerebrovascular and thrombotic vascular diseases since the 1970s.

Materials and methods

At present, the effect of ligustrazine on L-type calcium current (I_Ca-L) of ventricular myocytes remains controversial. In this study, we use the whole-cell patch-clamp techniques and video-based edge detection and dual excitation fluorescence photomultiplier systems to study the effects of ligustrazine on I_Ca-L, and calcium transient and contractility in rabbit ventricular myocytes in the absence and presence of isoprenaline (ISO).

Results

Ligustrazine (5 μM) in low concentration did not affect I_Ca-L (P>0.05), higher concentrations of this drug (10, 20, 40, 80 μM) inhibited I_Ca-L in a concentration-dependent manner and reduced I_Ca-L by 9.6±2.9%, 21.0±4.3%, 33.9±4.3%, and 51.6±7.3%, respectively. Under normal conditions, ligustrazine (40 μΜ) reduced baseline of fura-2 fluorescence intensities (FFI, 340/380 ratio), namely diastolic calcium concentration, changes in FFI (ΔFFI, 340/380 ratio) and maximal velocity of Ca²⁺ rise and decay (340/380 ratio/ms) by 6.3%, 26.1%, 25.2%, and 26.5%, and decreased sarcomere peak shorting (PS) and maximal velocity of shorting and relengthening by 36.4%, 31.9%, and 25.0%, respectively. Similarly, ligustrazine (40 μM) reduced baseline FFI, ΔFFI, and maximal velocity of Ca²⁺ rise and decay by 14.1%, 51.1%, 35.2%, and 41.1%, and reduced sarcomere PS and maximal velocity of shorting and relengthening by 38.6%, 50.0% and 39.1%, respectively, in the presence of ISO.

Conclusions

Ligustrazine not only significantly inhibits I_Ca-L in a concentration-dependent manner but also suppressed calcium transient and contraction in the absence and presence of ISO.     

Antispasmodic and antioxidant activities of fractions and bioactive constituent davidigenin isolated from Mascarenhasia arborescens

Ethnopharmacological relevance

Mascarenhasia arborescens A. DC. (Apocynaceae) is used in traditional medicine in the North of Madagascar to treat intestinal disorders, intestinal spasms and diarrhoea.

Aim of the study

The main objective of this work was to evaluate the antispasmodic activity of the crude methanolic extract of Mascarenhasia arborescens and of its four partitions and to identify the effective compound responsible for this effect.

Materials and methods

Isolation and structure elucidation techniques were performed in order to identify the bioactive constituent of Mascarenhasia arborescens and HPLC analysis was used for its quantification. Total phenolic content (TPC) of crude extracts and partitions were determined using the Folin–Ciocalteu method. Crude methanolic extract, partitions and the bioactive compound were investigated for their spasmolytic activity on several isolated organs. Their antiradical activity was also investigated by the DPPH test.

Results

Bioassay-guided fractionation using isolated guinea pig ileum pre-contracted with histamine 3 × 10⁻⁶ M led to the isolation of davidigenin (DG), a dihydrochalcone, as the main active constituent from the most promising methylene chloride partition (McP). This partition was effective on isolated guinea pig ileum pre-contracted with 3 × 10⁻⁶ M histamine, with a median effective concentration (EC₅₀) of 41.19 ± 3.74 μg/ml. The DG content of this partition was shown to be 26.5% by HPLC. DG induced a concentration-dependent relaxation of the histamine pre-contracted guinea pig ileum with an EC₅₀ of 8.04 ± 0.81 μg/ml and a concentration-dependent relaxation of the acetylcholine pre-contracted rat duodenum with an EC₅₀ of 9.35 ± 0.30 μg/ml. It inhibited in a non-competitive manner histamine-induced isolated ileum contraction and the acetylcholine-induced isolated duodenum contraction. Moreover, DG does not have any antiradical activity.

Conclusions

We demonstrated for the first time antispasmodic and antioxidant effects of Mascarenhasia arborescens. This study supports its use in traditional medicine. Furthermore, we highlighted the crucial role of davidigenin in the antispasmodic activity of this plant.     

Sedative and anticonvulsant activities of methanol extract of Dorstenia arifolia in mice

Ethnopharmacological relevance

Dorstenia arifolia is a plant that has been used in the folk medicine to produce hypnotic, sedative and ansiolitic effects but the pharmacological properties have not yet been studied. In addition, the smoke of its rhizome is reputed to induce lethargic sensation.

Aims of the study

The present study investigated possible activities of the methanol extract (ME) of Dorstenia arifolia rhizome on the central nervous system (CNS).

Materials and methods

ME was tested for sedative, hypnotic and anticonsulsant effects using locomotor activity evaluation, pentobarbital-induced sleeping time and pentylenetetrazol (PTZ)-induced convulsion, respectively.

Results

Intraperitoneal administration of ME (10 and 50 mg/kg) significantly decreased locomotor activity from 205.2 ± 25.6 movements/min (DMSO) to 112.1 ± 18.4 (P < 0.05) and 114.9 ± 16.9 (P < 0.05), respectively. Flumazenil (10 mg/kg), an antagonist of GABA_A receptor, prevented the ME-induced sedation. Treatment with ME (50 mg/kg) significantly increased the duration of pentobarbital-induced sleeping time from 41.0 ± 2.3 to 57.9 ± 2.9 min (P < 0.05). The latencies to seizures after intraperitoneal injection of PTZ was recorded and compared between groups. ME promoted a significant protection of PTZ-induced seizures and mortality in a dose-dependent manner.

Conclusions

Our findings indicate that ME of Dorstenia arifolia rizhome has pronounced central effects, and that the sedative and anticonvulsant activities may be related to a facilitation of the GABAergic transmission.     

Hypoglycemic effect of quassinoids from Brucea javanica (L.) Merr (Simaroubaceae) seeds

Ethnopharmacological relevance

The seeds of Brucea javanica (L.) Merr (Simaroubaceae) are recommended by traditional practitioners for the treatment of diabetes mellitus.

Aim of the study

To identify the compounds responsible for blood glucose lowering effect and evaluate the acute toxicity of the compounds.

Materials and methods

Extracts, fractions and subfractions were administered to normoglycemic mice and the blood glucose concentration was monitored for 8 h. Bioactive compounds isolated through column chromatography were administered to normoglycemic mice and streptozotocin (STZ) rats with monitoring of blood glucose concentration at 0–8 h. The acute toxicity was evaluated in mice.

Results

Bioactivity-guided fractionation led to the isolation of bruceines E (1) and D (2). Normoglycemic mice administered with 1 mg/kg of 1 and 2 exhibited significant blood glucose concentration reduction of 40.07 ± 11.45% and 48.82 ± 13.34%, respectively. STZ induced diabetic rats administered with 1 and 2 exhibited significant blood glucose concentration reduction of 73.57 ± 13.64% and 87.99 ± 2.91%, respectively.

Conclusion

The reduction of blood glucose concentration by both bruceines was comparable to glibenclamide and they might act as an insulin secretagogue. The presence of a hydroxyl moiety at C₂ in 1 reduced the toxic effect by 9-fold compared to 2.     

Vasorelaxant properties of acid and neutral fractions of Dimerocostus strobilaceus Kuntze used by Kuna Indians of Panama

Ethnopharmacological relevance

Dimerocostus strobilaceus is used by the Kuna Indians of Panama for the treatment of hypertension and other cardiovascular diseases.

Aim of the study

We investigated the vascular effects of acid and neutral fractions obtained from methanol and dichloromethane extracts of Dimerocostus strobilaceus.

Materials and methods

The acid and neutral methanol fractions (A-MeOH and N-MeOH) or acid and neutral dichlorometanic fractions (A-DCM and N-DCM) were tested using isolated rat aortic rings with or without endothelium pre-contracted by phenylephrine. We examined the ability of these different fractions at different concentrations to modify vascular responses induced by angiotensin II using endothelium-denuded aortic rings from Spontaneously Hypertensive Rats (SHR).

Results

In aortic rings with intact endothelium A-MeOH, N-MeOH and A-DCM fractions produced a concentration-dependent vasorelaxation (62.4 ± 5.2, 64.5 ± 5.0 and 63.7 ± 5.0%, respectively), whereas the N-DCM fraction did not produce any vasorelaxant effect. Maximal relaxation evocated by vasoactive fractions was substantially inhibited on aortic rings without endothelium.Our study demonstrates that A-MeOH, N-MeOH, A-DCM and N-DCM significantly reduce contractile responses induced by angiotensin-II on aortic rings.

Conclusions

Our findings may contribute to a better understanding of the potential link between vascular properties observed with Dimerocostus strobilaceus and their ethnobotanical use.     

Inhibitory effects of Bulnesia sarmienti aqueous extract on agonist-induced platelet activation and thrombus formation involves mitogen-activated protein kinases

Ethnopharmacological relevance

B. sarmienti has long been recognized in folk medicine as a medicinal plant with various medicinal uses. Traditionally, it has been appreciated for the skin-healing properties of its essence. The bark has also been employed to treat stomach and cardiovascular disorders and reported to have antitumor, antioxidant and anti-inflammatory activities. However, information on its antiplatelet activity is limited.

Aim of the study

To examined the effects of B. sarmienti aqueous extract (BSAE) in platelet physiology.

Materials and methods

The anti-platelet activity of BSAE was studied using rat platelets for in vitro determination of the extract effect on agonist-induced platelet aggregation, ATP secretion, [Ca²⁺]_i mobilization and MAP kinase phosphorylation. The extract in vivo effects was also examined in arterio-venous shunt thrombus formation in rats, and tail bleeding time in mice.

Result

HPLC chromatographic analysis revealed that B. sarmienti extract contained (+)-catechin (C), (−)-epigallocatechin (EGC), (−)-epicatechin (EC), and (−)-epicatechin gallate (ECG). BSAE, significantly and dose dependently, inhibited collagen, thrombin, or ADP-induced platelet aggregation. The 50 percent inhibitory concentrations (IC₅₀) of the extract for collagen, thrombin and ADP-induced platelet aggregation were 45.3 ± 2.6, 100 ± 5.6 and 110 ± 4.6 μg/ml, respectively. Collagen activated ATP release and thrombin-induced intracellular Ca²⁺ concentration were reduced in BSAE-treated platelets. In addition, the extract in vivo activity showed that BSAE at 100 mg/kg significantly attenuated thrombus formation in rat extracorporeal shunt model while mice tail bleeding time was not affected. Moreover, BSAE attenuated p38 mitogen-activated protein kinase (p38 MAPK), c-Jun N-terminal kinase 1 (JNK1) and extracellular-signal-regulated protein kinase 2 (ERK2) phosphorylations.

Conclusion

BSAE inhibits platelet activation, granule secretion, aggregation, and thrombus formation without affecting bleeding time, and that this effect is mediated by inhibition of P38, JNK1 and ERK2 phosphorylations. The ability of BSAE to inhibit platelet function might be relevant in cases involving aberrant platelet activation where the plant extract could be considered as a candidate to anti-platelet and antithrombotic agent.     

In vitro xanthine oxidase inhibitory activity of the fractions of Erythrina stricta Roxb.

Aim of the study

To assay the in vitro xanthine oxidase inhibitory activity of the various fractions of the hydromethanolic extract of the leaves of Erythrina stricta and to determine its enzyme inhibition mechanism.

Materials and methods

Xanthine oxidase inhibitory activity was assayed spectrophotometrically under aerobic conditions and the degree of enzyme inhibition was determined by measuring the increase in absorbance at 295 nm associated with uric acid formation. Enzyme kinetics was carried out using Lineweaver-Burk plots using xanthine as the substrate.

Results

Among the fractions tested, the chloroform fraction exhibited highest potency (IC₅₀ 21.2 ± 1.6 μg/ml) followed by the pet–ether (IC₅₀ 30.2 ± 2.2 μg/ml), ethyl acetate (IC₅₀ 44.9 ± 1.4 μg/ml) and residual (IC₅₀ 100 ± 3.3 μg/ml) fractions. The IC₅₀ value of allopurinol used, as the standard was 6.1 ± 0.3 μg/ml. Enzyme inhibition mechanism indicated that the mode of inhibition was of a mixed type.

Conclusion

These results suggest that the use of Erythrina stricta for the treatment of gout could be attributed to its xanthine oxidase inhibitory activity.     

Enhancement of oral moisture using tablets containing extract of Capparis masaikai Levl.

Aim of the study

This study was performed to examine the effects of tablets containing an extract of Capparis masaikai Levl. (M-tablets) on enhancing oral moisture.

Subjects and methods

The moistening effect of M-tablets was examined in 21 healthy subjects aged 25.1 ± 2.4 (mean ± S.D.) years in comparison with control tablets. After sucking tablets, the oral moisture was measured using a saliva wetness tester and a moisture checker. To evaluate the effects of the M-tablets on oral conditions, additional 50 subjects aged 30.6 ± 7.5 years were examined. The subjects recorded changes in refreshment, oral moisture, ease in speaking, and taste of water using a visual analog scale (VAS).

Results

The L-SALIVO^® value of the M-tablet increased significantly from 1.83 ± 0.17 (mean ± S.E.M.) at baseline to 3.02 ± 0.21 at 15 min (P < 0.01). The Mucus^® value of the M-tablet also increased from 37.50 ± 0.22 at baseline to 38.30 ± 0.26 at 15 min (P < 0.01). The VAS value for oral moisture increased significantly from 47.4 ± 2.0 to 69.6 ± 2.2 after taking the M-tablet (P < 0.01). The VAS value for taste of water also increased from 50.0 ± 1.1 to 66.7 ± 3.2 (P < 0.01).

Conclusion

These results suggest that M-tablets are useful for enhancing oral moisture, which leads to improvement of oral conditions.     

The effect of stroke and other components in Xing-Nao-Jing on the pharmacokinetics of geniposide

Ethnopharmacological relevance

Geniposide is a bioactive substance derived from gardenia, which has been used in traditional Chinese preparation, such as “Xing-Nao-Jing” (XNJ) for stroke treatment. Stroke and the ingredients of herbal preparation affect the pharmacokinetics of geniposide. A comparative pharmacokinetic study of geniposide in stroke and sham-operated rats after administration of XNJ and geniposide was proceeded to evaluate the effect of stroke on pharmacokinetics of geniposide, while the influence of other components in XNJ was determined by using gardenia extract and geniposide–borneol compounds in rats with stroke to compare.

Materials and methods

Stroke was induced by middle cerebral artery occlusion followed by reperfusion 2 h later. Plasma concentration of geniposide was determined by HPLC. Various pharmacokinetic parameters were estimated from the plasma concentration versus time data using non-compartmental methods.

Results

The maximum plasma concentration (C_max) and area under the curve (AUC_0−t) in stroke after administration of XNJ were 5.97±3.82 μg/mL, and 570.06±274.32 μg·min/mL, respectively, which were 5 times compared with sham-operated rats or the stroke-afflicted rats given geniposide. In stroke, the C_max and AUC_0−t of geniposide–borneol group and gardenia extraction group were close to XNJ group and geniposide group, respectively. The geniposide–borneol group had a higher value.

Conclusion

Stroke improved the absorption of geniposide in XNJ. Borneol may be the key ingredient in XNJ improving the absorption of geniposide.     

Investigation on modulation of human P-gp by multiple doses of Radix Astragali extract granules using fexofenadine as a phenotyping probe

Ethnopharmacology

Herb–drug interactions may potentially affect drug efficacy and/or the likelihood of adverse drug reactions. Radix Astragali (RA) extract formulation is usually prescribed for long-term use for patients with immunodeficiency, diabetes, nephropathy or cardiovascular diseases. Its use in combination with P-glycoprotein (P-gp) substrates is possible in clinical practice. Currently there is little knowledge about whether concomitant use of RA extract has an influence on disposition of P-gp substrate.

Aim of the study

This study was to investigate whether continuous and multiple doses of RA extract granules had modulatory effects on human P-gp.

Material and methods

A randomised, placebo-controlled, two-period crossover pharmacokinetic drug interaction study was conducted in healthy Chinese volunteers. Fexofenadine was used as a P-gp phenotyping probe. Fourteen volunteers received RA extract granules or placebo (4 g bid) for 7 days and then received a single oral dose of 120 mg fexofenadine. Fexofenadine plasma concentrations were determined by HPLC. Pharmacokinetic parameters were calculated by non-compartmental method and bioequivalence evaluation was performed.

Results

Pharamcokinetic parameters in the placebo phase were as follows: T_1/2 (3.75±1.47 h), C_max (745.11±137.41 μg/L), T_max (2.25±0.47 h), AUC_(0−t) (3894.27±923.45 μg h/L), AUC_(0−∞) (3993.84±912.97 μg h/L). Pharamcokinetic parameters in the RA extract phase were as follows: T_1/2 (4.00±1.24 h), C_max (709.44±170.03 μg/L), T_max (2.21±0.51 h), AUC_(0−t) (3832.72±1077.60 μg h/L), AUC_(0−∞) (3983.53±1019.83 μg h/L). The influence of RA extract on fexofenadine C_max and AUC lacks statistical significance. Fexofenadine in the two phases were bioequivalent. In the placebo phase, T_1/2 of fexofenadine in ABCB1 3435T mutation allele carriers was longer compared to ABCB1 3435CC carriers (4.43±1.44 h vs. 2.54±0.21 h, p<0.05). However, RA extract pretreatment abolished such genotype-related difference due to the lengthened T_1/2 in ABCB1 3435CC carriers. There was no association of the C3435T polymorphism with C_max and AUC_(0−t) in subjects with two pretreatments.

Conclusion

One-week administration of RA extract granules did not have a statistically significant impact on systematic exposure to fexofenadine, suggesting that RA extract is not a potent modulator of P-gp in vivo. RA extract appears to have ABCB1 C3435T genotype-dependent inhibitory effect on elimination rather than absorption of a P-gp substrate. Further investigations are necessary in patients who receive long-term use of RA extract formulation and combined P-gp substrates, especially in those ABCB1 3435CC carriers.     

Leucas cephalotes regulates carbohydrate and lipid metabolism and improves antioxidant status in IDDM and NIDDM rats

Ethnopharmacological relevance

Leucas cephalotes (Roth.) Spreng. (Laminaceae) is an ayurvedic traditional medicinal plant used in India, Nepal and Pakistan to treat several ailments including diabetes.

Aim of the study

The aim of the present study is to investigate the antidiabetic, antihyperlipaemic and antioxidant activities of Leucas cephalotes for its purported use in diabetes.

Materials and methods

The ethanol extract of leaves of Leucas cephalotes was administered (150, 300 and 450 mg kg⁻¹ bw) to diabetes induced (IDDM and NIDDM) rats and carbohydrate, lipid, antioxidant, urea and creatinine profiles were assessed.

Results

All the three doses of extract decreased plasma glucose and lipid profiles and, improved the antioxidant status of both types of diabetic rats. The extract administration improved hepatic glycogen content and hexokinase activity, decreased glucose-6-phosphatase activity, blood urea, creatinine contents and decreased lipid peroxidation in diabetic rats. Of the three doses used, 450 mg kg⁻¹ bw dose was found to be more potent in its effects comparable to those of glibenclamide and metformin.

Conclusion

Leucas cephalotes regulates both carbohydrate and lipid metabolism and, improves body antioxidant defense systems in both types of diabetes.     

Anti-inflammatory effect of bee venom on antigen-induced arthritis in rabbits: Influence of endogenous glucocorticoids

Aim of the study

This study assessed the involvement of endogenous glucocorticoids (GCs) in the anti-arthritic properties of bee venom (BV) on antigen-induced arthritis (AIA) in rabbits.

Materials and methods

BV (1.5–6 μg/kg/day) was injected for 7 days before AIA induction, whereas the control group received sterile saline. The total and differential leukocyte count, PGE₂ levels in synovial fluid and synovial membrane cell infiltrate were evaluated. The contribution of GCs to BV action was assessed in rabbits treated with BV plus metyrapone, an inhibitor of GC synthesis, or RU-38 486, a steroid antagonist.

Results

Treatment with BV (1.5 μg/kg/day) reduced the leukocyte count and PGE₂ level (18571 ± 1909 cells/mm³ and 0.49 ± 0.05 ng/mL, respectively) as well as the cellular infiltrate compared with the control group (40968 ± 5248 cells/mm³ and 2.92 ± 0.68 ng/mL, p < 0.05). The addition of metyrapone to BV treatment completely reversed the inhibition of AIA, whereas RU-38 486 was ineffective.

Conclusion

Our data show that bee venom treatment prevents the development of antigen-induced arthritis in rabbits through the action of GCs.