Anti-inflammatory, antioxidant, anti-tyrosinase and phenolic contents of four Podocarpus species used in traditional medicine in South Africa

Ethnopharmacological relevance

Species of Podocarpus are used traditionally in their native areas for the treatment of fevers, asthma, coughs, cholera, chest complaints, arthritis, rheumatism, venereal diseases and distemper in dogs.

Aims of the study

To investigate the antioxidant, anti-inflammatory and anti-tyrosinase activities of four Podocarpus species, Podocarpus elongatus, Podocarpus falcatus, Podocarpus henkelii and Podocarpus latifolius, used in traditional medicine in South Africa. Phytochemical analysis to determine the phenolic contents was also carried out.

Materials and methods

DPPH, FRAP and β-carotene-linoleic acid assays were used to determine the antioxidant/radical scavenging activities of these species. Anti-inflammatory activity of these species was assayed against two cyclooxygenase enzymes (COX-1 and COX-2). Tyrosinase inhibition activity was analysed using the modified dopachrome method with l-DOPA as the substrate. Phenolics were quantitatively determined using spectrophotometric methods.

Results

Stems of Podocarpus latifolius exhibited the lowest EC₅₀ (0.84 μg/ml) inhibition against DPPH. The percentage antioxidant activity based on the bleaching rate of β-carotene ranged from 96% to 99%. High ferric reducing power was observed in all the extracts. For COX-1, the lowest EC₅₀ value was exhibited by stem extracts of Podocarpus elongatus (5.02 μg/ml) and leaf extract of Podocarpus latifolius showed the lowest EC₅₀ against COX-2 (5.13 μg/ml). All extracts inhibited tyrosinase activity in a dose-dependent manner with stem extract of Podocarpus elongatus being the most potent with an EC₅₀ value of 0.14 mg/ml. The total phenolic content ranged from 2.38 to 6.94 mg of GAE/g dry sample.

Conclusion

The significant pharmacological activities observed support the use of these species in traditional medicine and may also be candidates in the search for modern pharmaceuticals in medicine, food and cosmetic industries.     

Vasorelaxant and antihypertensive effect of Cocos nucifera Linn. endocarp on isolated rat thoracic aorta and DOCA salt-induced hypertensive rats

Ethnopharmacological relevance

The fruits of Cocos nucifera Linn. (Arecaceae) have long been used in traditional medicine for the treatment of cardio-metabolic disorders.

Aim of the study

To evaluate the ethanolic extract of Cocos nucifera Linn. endocarp (CNE) for its vasorelaxant activity on isolated rat aortic rings and antihypertensive effects in deoxycorticosterone acetate (DOCA) salt-induced hypertensive rats.

Materials and methods

Cocos nucifera Linn. endocarp was extracted with ethanol and characterized by HPLC. CNE was examined for its in vitro vascular relaxant effects in isolated norepinephrine, phenylephrine or potassium chloride pre-contracted aortic rings (both intact endothelium and denuded). In vivo anti-hypertensive studies were conducted in DOCA salt-induced uninephrectomized male Wistar rats.

Results

Removal of endothelium or pretreatment of aortic rings (intact endothelium) with l-NNA (10 μM) or ODQ (10 μM) followed by addition of contractile agonists prior to CNE significantly blocked the CNE-induced relaxation. Indomethacin (10 μM) and atropine (1 μM) partially blocked the relaxation, whereas glibenclamide (10 μM) did not alter it. CNE significantly reduced the mean systolic blood pressure in DOCA salt-induced hypertensive rats (from 185.3 ± 4.7 mmHg to 145.6 ± 6.1 mmHg). The activities observed were supported by the polyphenols, viz. chlorogenic acid, vanillic acid and ferulic acid identified in the extract.

Conclusions

These findings reveal that the vasorelaxant and antihypertensive effects of CNE, through nitric oxide production in a concentration and endothelium-dependent manner, is due to direct activation of nitric oxide/guanylate cyclase pathway, stimulation of muscarinic receptors and/or via cyclooxygenase pathway.     

In vitro studies of Gynura divaricata (L.) DC extracts as inhibitors of key enzymes relevant for type 2 diabetes and hypertension

Aim of the study

To evaluate traditionally used herb, Gynura divaricata (L.) DC (Bai Bei San Qi) as in vitro inhibitors of key enzymes involved in the pathogenesis of hyperglycemia and hypertension. We also determined the distribution of enzyme inhibitory activities in different aqueous and non-aqueous extracts.

Materials and methods

The water extract (extract 1) from the aerial parts of Gynura divaricata (L.) was prepared first and then partitioned sequentially with n-butanol, ethyl acetate, and macroporous adsorptive resin (HPD-40) to yield extracts 2-4; the remaining water phase was named extract 5. Angiotensin-1 converting enzyme (ACE), α-amylase α-glycosidase inhibitory activities of the extracts were determined in vitro and chemical composition including total sugar, protein, flavonoid and total alkaloids in the extract were also evaluated.

Results

The water extract of this herb significantly inhibited (p < 0.05) ACE activity (IC₅₀ = 0.37 mg/ml) and showed a moderate potential hypoglycemic effect via in vitro α-amylase (IC₅₀ = 1.36 mg/ml) and α-glycosidase (IC₅₀ = 2.17 mg/ml) inhibition in dose-dependent manner. Further partitioning of the water extract (extracts 2-4) resulted in higher α-amylase inhibitory activities in extract 2 and 3. For α-glycosidase inhibition, extract 3 gave the highest inhibition. ACE inhibitory activities of the extracts were not improved by partitioning. Sugar, protein, flavonoid and alkaloid were found in water extract but only a small portion was partitioned in the n-butanol extract. However, a large portion of the flavonoids and alkaloids were found in ethyl acetate extract.

Conclusion

The results confirmed potential empirical use of Gynura divaricata (L.) DC for the management of hyperglycemia as well as hypertension. The active compounds for inhibition of α-amylase and α-glycosidase inhibition were flavonoids and alkaloids while ACE inhibition probably resulted from synergic effects of all the herb compounds.     

Relaxant effects of Artemisia ludoviciana on isolated rat smooth muscle tissues

Ethnopharmacological relevance

Artemisia ludoviciana spp. mexicana (Willd. Ex.) Spring D.D. Keck (Asteraceae), known as “estafiate” is employed for the treatment of diarrhea, dysentery, parasites, abdominal pain, vomiting, stomach ache, and also as antispasmodic agent. The aim of the present study was to evaluate the relaxant effect of hexanic (HEAl), dichloromethanic (DEAl) and methanolic (MEAl) extracts on isolated trachea, ileum and aorta rat rings, and to establish the tracheo-relaxant mode of action of DEAl.

Materials and methods

All extracts were investigated based on their capacity of to inhibit the rat ileum spontaneous contraction, to relax contraction induced by noradrenaline (0.1 μM) on endothelium-intact and endothelium-denuded thoracic aorta rat rings, and also to inhibit contraction provoked by carbachol (1 μM) on rat trachea.

Results

Organic extracts had no spasmolytic action on ileum strips compared to positive control (papaverine, p < 0.05). On the other hand, all extracts induced a significant concentration- and partial endothelium-dependent vasorelaxant activity. Extracts also showed significant relaxant effect on pre-contracted tracheal tissue in a concentration-dependent manner. In last two experiments, DEAl was the most potent and efficient extract; however, it was less potent than papaverine and theophylline, used as positive controls (p < 0.05). In tracheal preparation, DEAl shifted to the right, in a parallel manner, the concentration-response curves induced by carbachol (p < 0.05). Also, DEAl induced a significant relaxant effect on the contraction produced by potassium chloride (KCl, 80 mM). Pre-incubation with 1-H-[1,2,4]-oxadiazolo-[4,3a]-quinoxalin-1-one (ODQ, 10 μM), indomethacin (10 μM), N_ω-nitro-l-arginine methyl ester (l-NAME, 10 μM), glibenclamide (10 μM) and 2-aminopyridine (2-AP, 100 μM) did not modify the DEAl-relaxant curves.

Conclusions

Functional experiments suggest that the most active extract, DEAl, induced its relaxant effect by possible muscarinic receptors antagonism and calcium channel blockade in tracheal rings. On the other hand, significant vasorelaxant activity showed by DEAl is partially endothelium-dependent. Finally, spasmolytic activity induced by the extracts in the rat ileum was not significant, which suggests that the antidiarrheic effect of the plant is related to antimicrobial and antiparasitic properties previously described.     

Topical application of porcine placenta extract inhibits the progression of experimental contact hypersensitivity

Aim of study

Placenta extract features as a composition of ointments used for skin beautification, dermatological diseases and skin dryness. However, little evidence has been cited about its underlying mechanisms of action by which it exerts a beneficial role in dermatological diseases in vivo. In this study, we intended to test the effect of topical application of porcine placenta extract in mouse model of contact hypersensitivity and elucidate its mechanism of action.

Materials and methods

To test the in vitro effect of porcine placenta extract, RAW 264.7 cells were cocultured with porcine placenta extract and stimulated with LPS (1 μg/ml) and the expression of inflammatory mediator TNF-α was estimated by RT-PCR at the mRNA level and by intracellular staining at the protein level. To further test in vivo efficacy, porcine placenta extract was topically applied to the mice with experimental skin hypersensitivity. For in vivo studies placenta extract in gel form was topically applied to ear of DNCB-induced contact hypersensitivity mouse model everyday for 2 weeks and progression of the disease was estimated by following criteria: (a) ear thickness, (b) serum IgE level by ELISA, (c) histological examination of ear tissue by H&E staining and (d) cytokine profile of total cells and CD4⁺ T cells by real time PCR.

Results

Topical application of porcine placenta extract on mouse ears with contact hypersensitivity decreased the severity and progression of the disease manifested by reducing ear swelling, inflammation and edema. Histological evaluation showed that placenta extract treatment reduced lymphocyte infiltration in the ear tissues. Protective effect of placenta extract is also associated with down-regulation of serum IgE level and inflammatory cytokine production (IL-1β, IFN-γ, TNF-α, IL-4, IL-12 and IL-17) in total lymph node cells and CD4⁺ T cells.

Conclusions

Our data indicate that protective effect of porcine placenta extract in contact hypersensitivity is mediated by inhibition of the inflammatory responses and IgE production, suggesting a potential therapeutic application of porcine placenta extract to modulate skin inflammation.     

In vitro screening on β-amyloid peptide production of plants used in traditional medicine for cognitive disorders

Aim of the study

The aim of the study was to investigate the activity on β-amyloid peptide production of crude extracts of 9 plant species traditionally used in Benin or in Madagascar for the treatment of cognitive disorders, in order to select candidates for Alzheimer's disease treatment.

Materials and methods

For each species, hexane, dichloromethane, ethyl-acetate and water extracts were tested, at non-toxic concentrations, on CHO cells overexpressing the human neuronal β-amyloid peptide precursor (APP695) to measure variations of APP processing (by Western-blotting) and, for the most active, of Aβ-amyloid production (by ECLIA).

Results

We observed, at non-toxic concentrations, a significant increase in CTF/APP ratio with Oldenlandia affinis cyclotide-enriched fraction, Prosopis africana EtOAc extract, Pterocarpus erinaceus aqueous extract and Trichilia emetica hexane extract. We also showed that the Pterocarpus erinaceus extract significantly decreased Aβ production, displaying effects similar to those of DAPT (γ-secretase inhibitor) on APP processing, but may act on another inhibition site.

Conclusion

These active extracts are worth further studies to isolate the compounds responsible for the observed activities, to analyze their mode of action and determine their clinical potentials.     

Validated liquid chromatographic method and analysis of content of tilianin on several extracts obtained from Agastache mexicana and its correlation with vasorelaxant effect

Ethnopharmacological relevance

To optimize the obtention of tilianin, an antihypertensive flavonoid isolated from Agastache mexicana (Lamiaceae), a medicinal plant used in Mexico for the treatment of hypertension. Also, a validated HPLC method to quantify tilianin from different extracts, obtained by several extraction methods, was developed.

Materials and methods

The aerial parts of Agastache mexicana were dried at different temperatures (22, 40, 50, 90, 100 and 180 °C) and the dry material was extracted with methanol by maceration to compare the content of the active constituent tilianin in the samples. Furthermore, EtOH:H₂O (7:3), infusion and decoction extracts were prepared from air-dried samples at room temperature to compare the content and composition of the different extraction methods. Moreover, an ex vivo vasorelaxant test on endothelium-intact aortic rat rings was conducted, in order to correlate the presence of tilianin with the activity of each extract.

Results

Higher concentration and amounts of tilianin were determined from chromatograms in the obtained methanolic extracts from plant material dried at 90, 50, 40 and 22 °C, followed by 100 °C; however, lower concentrations were observed in dried at 180 °C and EtOH:H₂O (7:3). It is worth to notice that methanolic extracts with higher amount of tilianin were the most potent vasorelaxant extracts, even though these extracts were less potent than carbachol, a positive control used. Finally, decoction, infusion and EtOH:H₂O (7:3) extracts did not show any vasorelaxant effect.

Conclusion

Results suggest that extracts with higher concentration of tilianin possess the best vasorelaxant activity, which allowed us to have a HPLC method for future quality control for this medicinal plant.     

In vivo anti-inflammatory activities of leaf extracts of Ocimum lamiifolium in mice model

Aim of the study

Ocimum lamiifolium Hochst. ex Benth. (Lamiaceae) has been used in Ethiopian traditional medicine for the treatment of different inflammatory disorders such as oropharyngitis, wound, pain, fever, and others. However, its use has mainly been based on empirical findings. Thus the objective of this study was therefore to evaluate the antiinflammatory effects and acute oral toxicities of the leaf extracts of Ocimum lamiifolium in mice.

Materials and methods

Aqueous and ethanol crude extracts were screened for their antiinflammatory activities in mice using carrageenin induced paw edema. And then the aqueous extract, the most active extract, was further fractionated and the fractions were tested for their anti-inflammatory activities using carrageenin, histamine and serotonin induced mice paw edema. Distilled water and aspirin were employed as negative and positive controls, respectively. Acute oral toxicity of both extracts and fractions were also determined after giving graded doses.

Results

The aqueous and ethanol extracts were able to reduce inflammation significantly, but greater anti-inflammatory activity was observed for the aqueous extract at all dose levels. Of all fractions the water residue showed highly significant anti-inflammatory activity.

Conclusions

Ocimum lamiifolium leaf extracts exhibited significant anti-inflammatory activities with less acute toxicity.     

The anti-hypertensive effect of Danshen (Salvia miltiorrhiza) and Gegen (Pueraria lobata) formula in rats and its underlying mechanisms of vasorelaxation

Ethnopharmacological relevance

Radix Salviae miltiorrhizae (Danshen) and Radix Puerariae lobatae (Gegen) have long been used in traditional Chinese Medicine and serve as the principal herbs in treating cardiovascular disease.

Aims of the study

In the present study, an aqueous extract comprising Danshen and Gegen in the ratio of 7:3 (DG) was investigated for its anti-hypertension in vivo and vasodilative activities ex vivo.

Materials and methods

The anti-hypertensive effect of DG extract was investigated in spontaneously hypertensive rat (SHR) by measuring systolic blood pressure (SBP). Oral administration of DG extract was started at age of 6 weeks and 14 weeks for the preventive and therapeutic studies, respectively. Blood pressure was measured by tail-cuff method biweekly for 12 weeks. The ex vivo vasodilative activities of DG extract, its dependency on endothelium and the involvement of nitric oxide, prostacyclin and potassium channels were investigated using isolated rat aorta ring in organ bath.

Results

For in vivo study, systolic blood pressure was significantly reduced in DG extract-treated groups (90.2 and 300 mg/kg) as compared with the SHR control in both preventive and therapeutic studies. However, DG extract was unable to suppress or delay the onset of hypertension in the preventive study. For ex vivo study, the results showed that DG extract induced a concentration-dependent relaxation in aorta and persisted response was observed with the removal of endothelium. Besides, pretreatment with a non-selective potassium channel inhibitor tetraethylammonium (TEA) also significantly inhibited DG extract-induced vasodilation. Further investigations on specific potassium channel blockers revealed that ATP-sensitive potassium (K_ATP) channel inhibitor glibenclamide, inward rectifier potassium (Kir) inhibitor barium chloride and voltage-dependent potassium (K_v) channel inhibitor 4-aminopyridine, but not BK_Ca channel inhibitor iberiotoxin, exerted significant inhibition on DG extract-induced vasodilation.

Conclusions

The results of in vivo SHR animal model suggested that DG aqueous extract possessed blood pressure lowering effect on both pre- and post-hypertensive rats, which could be explained by its endothelium-independent vasodilation via the opening of K_ATP, Kir and K_v channels.     

Vasorelaxant and antihypertensive effects of methanolic extracts from Hymenocardia acida Tul

Ethnopharmacological relevance

In Congolese traditional medicine, decoctions of Hymenocardia acida root bark (HaRB) and trunk bark (HaTrB) are used for the treatment of conditions assumed to be hypertension. In this work, we propose to study the vasorelaxant effect of HaRB and HaTrB methanolic extracts on isolated rat thoracic aorta, to characterize the group of molecules responsible for the observed vasorelaxant activity, to evaluate the in vitro antioxidant activity of these extracts and to determine the antihypertensive activity of the HaRB extract on spontaneously hypertensive rats (SHR).

Materials and methods

The vasorelaxant effect of the HaRB and HaTrB methanolic extracts was studied on endothelium-intact aortic rings pre-contracted with phenylephrine (PE, 1 μM). The mechanism of this vasorelaxant effect was investigated on endothelium-denuded vessels and on endothelium-intact aortic rings in the presence of three inhibitors: l-N^G-nitroarginine methyl ester (100 μM), indomethacin (10 μM) and 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one (10 μM). To determine the nature of the compounds responsible for the vasorelaxant activity, we carried out a fractionation of the extracts and a thiolysis of the most active fraction followed by a liquid chromatography/electrospray ionization mass spectrometry (LC/ESI-MS) analysis. The extracts antioxidant activity was determined by the 2,2-diphenyl-1-picrylhydrazyl (DPPH) colorimetric assay. In vivo anti-hypertensive activity of the HaRB extract was conducted on SHR.

Results

HaRB and HaTrB methanolic extracts produced a concentration-dependent vasorelaxation on intact aortic rings pre-contracted with PE (1 μM). The vasorelaxant responses obtained were 95.3±1.5% (5 μg/ml) and 100.6±3.0% (1 μg/ml), respectively. The effect was markedly attenuated by removal of endothelium or pretreatment of aortic rings with all inhibitors except indomethacin. The LC/ESI-MS analysis of the thiolysis products indicated that the fraction which caused the most important vasorelaxation (97.9±2.5% at 3 μg/ml) was a mixture of procyanidins and prodelphinidins, with a predominance of procyanidins. Both extracts and all fractions from HaRB extract showed a DPPH scavenging activity, ranging from 0.4 to 0.8 quercetin-equivalents. The HaRB methanolic extract reduced the systolic blood pressure in SHR (from 214±3 mmHg to 194±4 mmHg) after a 5-week treatment.

Conclusions

The methanolic extracts of Hymenocardia acida root and trunk bark have vasorelaxant activity. The vasorelaxant effect observed is endothelium-dependent and seems mainly mediated through the NO-cGMP pathway. The COX pathway is not involved. The vasorelaxant activity appears to be due to polymeric procyanidins and prodelphinidins. These extracts also have an antioxidant effect. The extract of Hymenocardia acida root bark shows a significant but weak antihypertensive activity in SHR.     

Bacopa monnieri and its constituents is hypotensive in anaesthetized rats and vasodilator in various artery types

Ethnopharmacological relevance

Bacopa monnieri (Brahmi) provides traditional cognitive treatments possibly reflecting improved cerebral hemodynamics. Little is known about the cardiovascular actions of Brahmi. We sought to assess its effects on blood pressure and on isolated arteries, thus providing insights to clinical applications.

Materials and methods

Intravenous Brahmi (20-60 mg/kg) was tested on arterial blood pressure and heart rate of anaesthetized rats. In vitro vasorelaxation was assessed in arteries, with and without blockers of nitric oxide synthase (L-NAME), cyclooxygenase (indomethacin), and mechanical de-endothelialisation. The effects of Brahmi on Ca²⁺ influx and release from stores were investigated.

Results

Intravenous Brahmi extract (20-60 mg/kg) decreased systolic and diastolic pressures without affecting heart rate. Brahmi evoked relaxation in isolated arteries in order of potency: basilar (IC50 = 102 ± 16 μg/ml) > mesenteric (171 ± 31) > aortae (213 ± 68) > renal (IC50 = 375 ± 51) > tail artery (494 ± 93) > femoral arteries (>1000 μg/ml). Two saponins, bacoside A3 and bacopaside II, had similar vasodilator actions (IC50 = 8.3 ± 1.7 and 19.5 ± 6.3 μM). In aortae, without endothelium or in L-NAME (10-4 M), Brahmi was less potent (IC50 = 213 ± 68 to 2170 ± 664 and 1192 ± 167 μg/ml, respectively); indomethacin (10-5 M) was ineffective. In tail artery, Brahmi inhibited K⁺-depolarization induced Ca²⁺ influx and Ca²⁺ release from the sarcoplasmic reticulum by phenylephrine (10-5 M) or caffeine (20 mM).

Conclusions

Brahmi reduces blood pressure partly via releasing nitric oxide from the endothelium, with additional actions on vascular smooth muscle Ca²⁺ homeostasis. Some Brahmi ingredients could be efficacious antihypertensives and the vasodilation could account for some medicinal actions.     

South African plants used in traditional medicine to treat epilepsy have an antagonistic effect on NMDA receptor currents

Ethnopharmacological relevance

Several Searsia species (Anacardiaceae), including Searsia dentata and Searsia pyroides, are used in South Africa traditional medicine to treat epilepsy. Ethanol leaf extracts of these plants have been shown to act as possible antagonists of N-methyl-d-aspartate (NMDA)-type glutamate receptors.

Materials and methods

Leaf material of three Searsia species were collected from the Botanical Garden at the University of KwaZulu-Natal, Pietermaritzburg; dried and extracted with ethanol in an ultrasound bath. Filtered and dried extracts were resuspended in DMSO (100 mg/ml) and diluted in the recording solution. The effect of Searsia dentata, Searsia pyroides and Searsia glauca extracts was investigated in dissociated cerebellar granule cells (CGCs) from 8-day-old rats and in transiently transfected HEK (human embryonic kidney) 293 cells (HEK), expressing either NR1a/NR2A or NR1a/NR2B receptors. In both systems we measured whole-cell currents elicited by 0.5 mM NMDA (CGCs) or 50 μM glutamic acid (HEK) at −60 mV in 0 Mg and 30 μM glycine and NMDA driven Ca influx in Fura2-loaded CGC.

Results

Searsia dentata and Searsia pyroides ethanol extracts caused a dose-dependent decrease of NR current with ED₅₀ close to 0.03 mg/ml in CGC and a similar inhibition (80% with 1 mg/ml) in HEK cells, while Searsia glauca was much less effective. The inhibition was dependent on time of incubation and slightly favored by opening of the NR channel. It was hardly reversible during the recording time, but was not caused by accelerated run-down or by interaction with the modulatory redox site. Searsia pyroides ethanol extract also depressed the NMDA stimulated increase in intracellular Ca.

Conclusions

The data confirm the specificity of Searsia dentata and Searsia pyroides and justify their use in traditional medicine. These plants may combine one or more γ-aminobutyric acid (GABA)_A agonists with one or more NMDA antagonists, thus representing an efficient treatment for epilepsy.     

Pentacyclic triterpenoids and ceramide mediate the vasorelaxant activity of Vitex cienkowskii via involvement of NO/cGMP pathway in isolated rat aortic rings

Ethnopharmacological relevance

Vitex cienkowskii Kotschy & Peyritsch is a deciduous tree, prescribed by Cameroonian traditional healers as one of the most popular plant widely used in many disorders including cardiovascular diseases. The preliminary pharmacological studies carried out on Vitex cienkowskii showed its vasorelaxant activities on guinea-pig aortic rings.

Aim of the study

The present work evaluated the vasorelaxant activity of extract and isolated compounds from Vitex cienkowskii.

Materials and methods

Rat aortic rings were used to evaluate the in vitro vascular effect of the extract. The antioxidant activity was determined by measuring the reduction of the free radical 1,1-diphenyl-1-picryl-hydrazyl (DPPH).

Results

Vitex cienkowskii induced significant relaxation in a concentration- and endothelium-dependent manner (EC₅₀ = 12.12 μg/ml, CH₂Cl₂-MeOH, 1:1) and did not produce a vasorelaxant effect on contraction evoked by KCl (60 mM). In order to determine its mode of action, Vitex cienkowskii-induced relaxant effect was evaluated in the presence of indomethacin (10 μM), L-NAME (100 μM), ODQ (1 μM) and SQ22356 (100 μM). Relaxation was significantly blocked by L-NAME and ODQ. These results indicate that Vitex cienkowskii-mediated relaxation is endothelium dependent, probably due to NO release, and the consequent activation of vascular smooth muscle soluble guanylate cyclase (sGC), a signal transduction enzyme that forms the second messenger cGMP. Bio-guided study of Vitex cienkowskii allowed the isolation of the known pentacyclic triterpenoids and a ceramide. It is the first report of salvin A, maslinic acid and a ceramide from Vitex cienkowskii. The activity induced by these compounds indicated that they may be partly responsible for the vasorelaxant effect of the plant extract.A dose of 40 mg/kg of CH₂Cl₂-MeOH (1:1) extract administered intravenously induced a decrease of mean arterial pressure but did not affect the heart rate. Moreover the plant extracts were found to be highly active in the DPPH radical scavenging assay.

Conclusion

Vitex cienkowskii extract possesses antioxidant property, vasorelaxing, and hypotensive effect linked to the endothelium related factors, where nitric oxide is involved.     

Polysaccharide fractions of Caesalpinia ferrea pods: potential anti-inflammatory usage

Ethnopharmacological relevance

Caesalpinia ferrea (Caesalpinioideae), known as pau-ferro or juca, has been used in the traditional medicine in North and Northeast of Brazil in inflammatory disorder, among others. Thus, experimental evaluation of the anti-inflammatory activity of extracts and fraction polysaccharides of Caesalpinia ferrea pods, and correlation with its anti-inflammatory activity and popular use is important.

Materials and methods

Total polysaccharides (TPL) were applied to ion exchange chromatography and eluted stepwise. Paw edema was induced s.c. by λ-carrageenan, dextran, histamine, serotonin, compound 48/80, bradykinin, prostaglandin E₂ (PGE₂) or l-arginine and analyzed by plethysmometry and protein leakage by spectrophotometry. Peritonitis was induced i.p. by carrageenan or N-formyl-methionyl-leucyl-phenylalanine (fMLP) and analyzed 4 h later for leukocyte migration and protein leakage. Animals were treated i.v. with TPL or polysaccharide fractions (0.01, 0.1, 1 mg/kg) 30 min before stimuli in both models. Toxicity (variation of body/organ mass and hematological/biochemical parameters) was evaluated after the seven-day treatment with the most active polysaccharide fraction (1 mg/kg; i.v.).

Results

Chromatography of TPL (2.8% yield) provided three major polysaccharide fractions (FI, FII, FIII). At 1 mg/kg, TPL inhibited the paw edema induced by carrageenan (60%) and FIII (fraction presenting high carbohydrate and low protein content) inhibited the inflammatory parameters in the paw edema induced by the following stimuli: carrageenan (70%), dextran (53%), histamine (65%), serotonin (62%), bradykinin (60%), PGE₂ (63%), nitric oxide (61%) and compound 48/80 (36%). Additionally, FIII at 1 mg/kg inhibited the carrageenan-induced edema in animals with intact mast cells, but only the late phase of those with degranulated mast cells elicited by compound 48/80. Moreover, FIII inhibited cell migration and protein leakage in the model of peritonitis elicited by carrageenan (88%) and fMLP (64%), being well tolerated by animals.

Conclusions

Extracts and polysaccharide fractions of Caesalpinia ferrea pods exhibit potent anti-inflammatory activity via negative modulation of histamine, serotonin, bradykinin, PGE₂ and NO released in the carrageenan-induced edema, showing involvement of mast cells. FIII could be interfering not only in the vascular, but also in cellular inflammatory events, revealing to be an important active component of traditionally prepared remedies used to treat inflammatory states.     

Sedative, vasorelaxant, and cytotoxic effects of convolvulin from Ipomoea tyrianthina

Aim of the study

Ipomoea tyrianthina has been used in Mexican traditional medicine as a mild purgative, for the treatment of nervous disorders, and against tumors. In this study, the effect of convolvulin (an ether-insoluble resin glycoside) from the root of Ipomoea tyrianthina on: Central Nervous System; as spasmolytic and vasodilator; cytotoxic against cancer cell lines is evaluated.

Materials and methods

Convolvulin isolated from the root of Ipomoea tyrianthina (IT-EM) was tested on pentylentetrazole induced seizures, pentobarbital-induced hypnosis, release of GABA and glutamic acid, isolated rat aorta and ileum rings, and against Caco-2 and KB cell lines.

Results

IT-EM increased the hypnotic effect induced by pentobarbital and the release of GABA in brain cortex of mice, but did not protect mice against pentylenetetrazole-induced convulsions. IT-EM produced a significant vasodilator effect in concentration- and endothelium-dependent manners on isolated rat aorta, but did not inhibit significantly contractions on rat ileum, colon, and jejune rings. IT-EM showed cytotoxic activity against nasopharyngeal carcinoma KB cell line.

Conclusions

Convolvulin (IT-EM) from Ipomoea tyrianthina has sedative effect, vasorelaxant effect in concentration- and endothelium-dependent manners, and cytotoxic activity against nasopharyngeal carcinoma KB cell line.     

Antihypertensive and neuroprotective activities of rhynchophylline: The role of rhynchophylline in neurotransmission and ion channel activity

Ethnopharmacological relevance

Uncaria species (Gouteng in Chinese) have been used as ethnopharmacological medicines to treat ailments of the cardiovascular and central nervous systems. As the main alkaloid constituent of Uncaria species, rhynchophylline has drawn extensive attention in recent years for its antihypertensive and neuroprotective activities, and its pharmacological effects are related to ethnopharmacological medicine properties of Uncaria species.

Aim of the review

This review examined the pharmacological studies and mechanisms of rhynchophylline, with an emphasis on cardiovascular and central nervous system diseases linked to the ethnopharmacological uses of Uncaria species.

Methods

We conducted both an electronic search and a library search of in vivo and in vitro studies. The terms and keywords for the search included rhynchophylline, Uncaria species, Gouteng, pharmacological effects, and mechanism. We focused on the papers, including ours, with studies on all related pharmacological effects and mechanisms of rhynchophylline.

Results

Rhynchophylline was the main constituent of several components identified from Uncaria species. Rhynchophylline mainly acts on cardiovascular and central nervous system diseases, including hypertension, bradycardia, arrhythmia, sedation, vascular dementia, epileptic seizures, drug addiction, and cerebral ischemia. Rhynchophylline also has effects on anticoagulation, inhibits vascular smooth muscle cell proliferation, and has been shown to be anti-endotoxemic. The active mechanisms are related to modulation of calcium and potassium ion channels, protection of neural and neuroglial cells, and regulation of central neurotransmitter transport and metabolism. More studies are necessary to verify the pharmacological activities and determine the exact mechanisms of rhynchophylline activity.

Conclusions

Rhynchophylline treatment of cardiovascular and central nervous system diseases has a strong linkage with traditional concepts and uses of Uncaria species in ethnopharmacological medicine, such as treatment for lightheadedness, convulsions, numbness, and hypertension. As a candidate drug for several cardiovascular and central nervous system diseases, rhynchophylline will attract scientists to pursue the potential pharmacological effects and mechanisms with new technologies. Relatively few clinically relevant studies of rhynchophylline have been conducted. Thus, more in vivo validations and investigations of antihypertensive and neuroprotective mechanisms of rhynchophylline are necessary.     

Antibacterial, antioxidant and fibroblast growth stimulation activity of crude extracts of Bridelia ferruginea leaf, a wound-healing plant of Nigeria

Aim of the study

Determination of pharmacological activity relevant to wound healing of Bridelia ferruginea leaf, a traditional medicine used to treat wounds in rural Nigeria.

Materials and methods

Aqueous and ethanolic leaf extracts were tested against bacterial species of relevance to wound infections: Staphylococcus aureus, Bacillus subtilis, Escherichia coli and Pseudomonas aeruginosa. The ethanolic extracts were assessed for their ability to stimulate the growth of human dermal fibroblasts (FS5) and protect against damage induced by hydrogen peroxide. Antioxidant activity was also assessed using the DPPH assay.

Results

Both aqueous and ethanolic extracts had weak antibacterial activity (MIC > 470 μg/ml). A significant effect (p < 0.001) on the growth of FS5 fibroblasts was observed only at a concentration of 5 μg/ml (28% increase), above which the extracts appeared toxic to the cells. The ethanolic extract offered the highest protection against H₂O₂ damage to FS5 cells, comparable with catalase (82% at 250 μg/ml). The DPPH assay revealed antioxidant activity of the ethanolic leaf extract with IC₅₀ 12.5 ± 0.3 μg/ml comparable to l-ascorbic acid (7.3 ± 0.1 μg/ml).

Conclusion

The antibacterial, modest fibroblast stimulation activity and relatively strong antioxidant activity lend some support to the topical use of Bridelia ferruginea leaf for wound-healing in the traditional medicine of South-western Nigeria.     

In vitro antimicrobial synergism within plant extract combinations from three South African medicinal bulbs

Ethnopharmacological relevance

Tulbaghia violacea, Hypoxis hemerocallidea and Merwilla plumbea are used in South African traditional medicine for the treatment of some infectious diseases and other ailments.

Aim of the study

The study aimed at investigating the antimicrobial efficacies of independent and various within-plant extract combinations of three medicinal bulbs to understand the possible pharmacological interactions.

Materials and methods

Bulb and leaf extracts of the three medicinal plants, independently and in combinations, were comparatively assessed for antimicrobial activity against two Gram-positive and two Gram-negative bacteria and Candida albicans using the microdilution method. The fractional inhibitory concentration indices (FIC) for two extract combinations were determined.

Results

At least one extract combination in each plant sample demonstrated good antimicrobial activity against all the test organisms. The efficacies of the various extract combinations in each plant sample varied, with the strongest synergistic effect exhibited by the proportional extract yield combination of PE and DCM extracts in Merwilla plumbea bulb sample against Staphylococcus aureus (FIC index of 0.1). Most extract combinations demonstrated either a synergistic, additive or indifferent interaction effect against the test bacteria with only a few exhibiting antagonistic effects.

Conclusion

The observed antimicrobial efficacy and synergistic interactions indicate the beneficial aspects of combination chemotherapy of medicinal plant extracts in the treatment of infectious diseases.     

Anti-inflammatory and antioxidant effects of a hypoglycemic fructan fraction from Psacalium peltatum (H.B.K.) Cass. in streptozotocin-induced diabetes mice

Ethnopharmacological importance

Psacalium peltatum (H.B.K.) Cass. (Asteraceae) is used medicinally to treat diabetes, rheumatic pains, as well as gastrointestinal and kidney ailments. Previous pharmacological and chemical assays have demonstrated that an aqueous fraction from Psacalium peltatum (AP-fraction) contains a carbohydrate-type compound with hypoglycemic activity. Nevertheless, studies have not yet considered the hypoglycemic action of the AP-faction by sub-chronic administration nor on other healing properties, some of which might be associated with DM2 and other inflammatory processes.

Aim of study

To determine whether a hypoglycemic carbohydrate fraction (AP-fraction) from Psacalium peltatum roots has antioxidant and anti-inflammatory effects in streptozotocin-induced diabetes mice.

Material and methods

Healthy mice received either saline, the AP-fraction with a high content of fructans, or pioglitazone (a positive control) daily by gavage. After 15 days of treatment, these animals received a single intraperitoneal administration of streptozotocin and all treatments were continued for additional 33 days. The antioxidant and anti-inflammatory properties of the AP-fraction were evaluated through the quantification of biomarkers of oxidative stress (glutathione (GSH) and malondialdehyde (MDA)) and inflammation (interleukin (IL)-6, tumor necrosis factor alpha (TNF-α), interferon-gamma (IFN-γ), and IL-10).

Results

The AP-fraction reduced glycemia and the glycated hemoglobin. Furthermore, animals treated with the AP-fraction had increased GSH, while MDA was decreased in the liver and the heart, without changes in the kidneys and the pancreas. The AP-fraction significantly reduced TNF-α serum levels but did not modify IL-6; in addition, this fraction increased IFN-γ and IL-10 levels. The increase in IL-10 levels may indicate an inhibition of the production of pro-inflammatory cytokines such as TNF-α, whereas the increase in IFN-γ might be indicative of a beneficial effect on the immune system.

Conclusions

The AP-fraction hypoglycemic fructans from Psacalium peltatum roots showed antioxidant and anti-inflammatory properties in mice with streptozotocin-induced diabetes. The Psacalium peltatum hypoglycemic fructans may be valuable in preventing insulin resistance, as well as the development and progression of diabetic complications caused by chronic inflammation.