Pharmacological evaluation of Alstonia scholaris: Anti-inflammatory and analgesic effects

Ethnopharmacological relevance

Alstonia scholaris (Apocynaceae) has been historically used in “dai” ethnopharmacy to treat chronic respiratory diseases. The leaf extract, developed as a commercially available traditional Chinese medicine, used to release tracheitis and cold symptom, has also been prescribed in hospitals and sold over the counter in drug stores.

Aim of the study

The investigation evaluated the anti-inflammatory and analgesic activities of the ethanolic extract, fractions and main alkaloids of Alstonia scholaris leaf to provide experimental evidence for its traditional and modern clinical use. Besides, to discover the active fraction and components for further better use in Chinese medicine is hopeful.

Materials and methods

The leaf of Alstonia scholaris was extracted with ethanol and then separated into different fractions. Furthermore, alkaloids were isolated by phytochemical method. The analgesic activities were investigated using acetic acid-induced writhing, hot-plate and formalin tests in mice. The anti-inflammatory activities were carried out in vivo and in vitro, including xylene-induced ear edema and carrageenan-induced air pouch formation in mice, and COX-1, -2 and 5-LOX inhibition.

Results

It has been exhibited that the EtOAc and alkaloid fractions reduced acetic acid-induced writhing response in mice, significantly. The ethanolic extract, EtOAc and alkaloid fractions remarkably inhibited xylene-induced ear edema. Further investigation was focused on the alkaloids fraction and three main alkaloids isolated from the alkaloids fraction, in different animal models. Alkaloids reduced acetic acid-induced writhing response, and xylene-induced ear edema in mice. In the hot-plate test, alkaloids did not increase the latency period of mice obviously. In the formalin test, alkaloids did not inhibit the licking time in first phase, but significantly inhibited the licking time in second phase of mice. Alkaloids increased significantly SOD activity and decreased levels of NO, PGE2 and MDA significantly, in air pouch mice model. Moreover, some alkaloids isolated from the leaf of Alstonia scholaris exhibited inhibition of COX-1, COX-2 and 5-LOX in vitro anti-inflammatory assay, which supported alkaloids as the bioactive fraction.

Conclusions

The alkaloids fraction of Alstonia scholaris leaf, three main alkaloids, picrinine, vallesamine and scholaricine, may produce the anti-inflammatory and analgesic effect peripherally based on several in vivo assays. In in vitro tests, alkaloids exhibited inhibition of inflammatory mediators (COX-1, COX-2 and 5-LOX), which is accordant with results on animal models. Besides, COX-2/5-LOX dual inhibitors found in the experiment, such as 16-formyl-5α-methoxystrictamine, picralinal, and tubotaiwine might be valuable for further attention.     

Antitussive,expectorant and bronchodilating effects of ethanol extract of Sorghum bicolor (L.) Moench roots

Ethnopharmacological relevance

Root of Sorghum bicolor (L.) Moench (RSB) is an herbal medicine in Traditional Chinese Medicine, still used in some rural areas in Central China as an alternative remedy to treat cough and asthma.

Aim of the study

The study was aimed at evaluating the antitussive, expectorant and bronchodilating effects of ethanol extract of RSB, support its folk use with scientific evidence, and lay a foundation for its further researches.

Materials and methods

RSB was extracted with 80% ethanol aqueous in reflux conditions, solutions were concentrated in reduced pressure, and lyophilized in vacuum to yield the RSB extract. Antitussive evaluations were carried out with three different models including ammonia liquor induced mice cough, capsaicin induced mice cough, and citric acid induced guinea pigs cough; phenol red secretion experiments in mice were performed to evaluate the expectorant ability; bronchodilating effects were evaluated with a bronchoconstrictive challenge induced by acetylcholine chloride and histamine in guinea pigs.

Results

In all the three antitussive tests, treatment of RSB significantly inhibited the frequency of cough, and prolonged the cough latent period in animals. And high dose of RSB (200 mg/kg in mice and 100 mg/kg in guinea pigs) created therapeutic activities as good as standard antitussive drug codeine phosphate (20 mg/kg). In the expectorant evaluation, 50, 100 and 200 mg/kg RSB treatment had significantly increased the amount of phenol red output for 0.39, 1.18, and 1.96 folds in mice tracheas. In the bronchodilating test, RSB treatment at 100 mg/kg extended the preconvulsive time for 44.84% compared with that of before treatment in guinea pigs.

Conclusions

RSB is an effective alternative medicine for the treatment of cough with potent antitussive, expectorant and bronchodilating activities.     

Alstonia scholaris (L.) R. Br. and Alstonia macrophylla Wall. ex G. Don: A comparative review on traditional uses,phytochemistry and pharmacology

Ethnopharmacological relevance

Alstonia scholaris (L.) R. Br. and Alstonia macrophylla Wall. ex G. Don are two vital medicinal plant species (family: Apocynaceae). In India, the therapeutic use of Alstonia scholaris has been described in both codified and non-codified drug systems for the treatment of malaria, jaundice, gastrointestinal troubles, cancer and in many other ailments. Other species, Alstonia macrophylla has been used in conventional medicines in Thailand, Malaysia and Philippines as a general tonic, aphrodisiac, anticholeric, antidysentery, antipyretic, emmenagogue, and vulnerary agents. In India, Alstonia macrophylla is used as a substitute for Alstonia scholaris in various herbal pharmaceutical preparations. However, one certainly cannot evaluate the truthfulness of a practice (i.e. in scientific terms). In this article we discuss and summarize comparative data about traditional uses, phytochemistry, pharmacology and toxicity of Alstonia scholaris and Alstonia macrophylla. Moreover, in order to unfold future research opportunities, lacunae in the present knowledge are also highlighted.

Materials and methods

Literature about Alstonia scholaris and Alstonia macrophylla was collected by using electronic and library search. Additionally, referred books on traditional medicine and ethnopharmacology were also utilized for receiving traditional records about both the plant species.

Results

Both Alstonia scholaris and Alstonia macrophylla are rich in different types of bioactive alkaloids. So far, broad spectrum of in vitro and in vivo biological and pharmacological activities have been reported to both the species. Amongst them, antimicrobial and anticancer activities were promising.

Conclusions

The use of Alstonia macrophylla as a substitute for Alstonia scholaris is not at all justifiable as both the species are distinct from each other in their phytochemistry and pharmacology. Further detail chemical fingerprinting and metabolic studies of these two species are warranted to prevent their mutual adulteration most importantly in the context of commercial preparations.     

Antitussive and central respiratory depressant effects of Stemona tuberosa

Aims of the study

Stemona alkaloids with distinctly different chemical skeletons are recently reported as the active components in the antitussive herb Baibu derived from the root-tubers of Stemona tuberosa. This study aims to determine if alkaloids of this herb contribute equally to the antitussive functions, act on the same sites of cough reflex, and play any role in inducing central respiratory depressant effects.

Materials and methods

Antitussive potency of four major alkaloids was evaluated on guinea pigs with citric acid aerosol to induce cough. The action sites of the alkaloids on cough reflex pathway were tested with electrical stimulation of the superior laryngeal nerve in guinea pigs. The central respiratory effects of croomine were also tested on guinea pigs.

Results

Croomine, neotuberostemonine and stemoninine showed similar antitussive potency, while tuberostemonine showed much weaker antitussive potency. Neotuberostemonine, tuberostemonine and stemoninine acted on the peripheral cough reflex pathway, while croomine acted on the central part. Croomine also showed obvious central respiratory depressant effects.

Conclusions

The four major Stemona alkaloids in Stemona tuberosa do not contribute equally to antitussive potency in guinea pigs. Neotuberostemonine, tuberostemonine and stemoninine target on peripheral cough reflex pathway. Croomine acts on central sites in the cough reflex pathway and demonstrates central respiratory depressant effects, which can partly account for the adverse reactions reported for the herb.     

Metabolomic profiling of the flower bud and rachis of Tussilago farfara with antitussive and expectorant effects on mice

Ethnopharmacological relevance

Flower bud of Tussilago farfara L. is widely used for the treatment of cough, bronchitis and asthmatic disorders in the Traditional Chinese Medicine. However, due to the increasing demands, adulteration with rachis is frequently encountered in the marketplace. No report demonstrated the chemical and pharmacological differences between flower bud and rachis before.

Materials and methods

The water extracts were orally administrated to mice. Ammonia induced mice coughing model was used to evaluate the antitussive activity. The expectorant activity was evaluated by volume of phenol red in mice's tracheas. Metabolites were identified directly from the crude extracts through 1D- and 2D-NMR spectra. A metabolic profiling carried out by ¹H NMR spectroscopy and multivariate data analysis was applied to crude extracts from flower bud and rachis.

Results

Flower bud significantly lengthened the latent period of cough, decreased cough frequency caused by ammonia and enhanced tracheal phenol red output in expectorant evaluation. Principal component analysis (PCA) yielded good separation between flower bud and rachis, and corresponding loading plot showed that the phenolic compounds, organic acid, sugar, amino acid, terpene and sterol contributed to the discrimination.

Conclusions

These findings provide pharmacological and chemical evidence that only flower bud can be used as the antitussive and expectorant herbal drug. The high concentration of chlorogenic acid, 3,5-dicaffeoylquinic acid, rutin in flower buds may be related with the antitussive and expectorant effects of Flos Farfara. To guarantee the clinical effect, rachis should be picked out before use.     

Antitussive, expectorant and anti-inflammatory activities of four alkaloids isolated from Bulbus of Fritillaria wabuensis

Ethnopharmacological relevance

Bulbus Fritillaria Cirrhosae (BFC), known by the Chinese name “Chuan-Bei-Mu”, is used as an antitussive, antiasthmatic and expectorant drug for more than 2000 years in China, and Bulbus of Fritillaria wabuensis S. Y. Tang & S. C. Yueh (BFW) was recorded in the 2010 edition of China Pharmacopoeia as one of sources for BFC. The primary objective of this study was to evaluate the antitussive, expectorant and anti-inflammatory effects of alkaloids - imperialine, imperialine-β-N-oxide, isoverticine, and isoverticine-β-N-oxide, which were isolated from BFW, and to provide experimental evidence for its traditional use.

Materials and methods

The alkaloids were isolated using phytochemical methods, and their structures were determined by spectroscopic analysis. Their antitussive effects were measured using murine model of ammonia induced cough, the expectorant effects were evaluated by measuring mice's tracheal phenol red output, and the anti-inflammatory effects were assessed by using the murine model of xylene induced ear edema.

Results

The structures of the four alkaloids - imperialine, imperialine-β-N-oxide, isoverticine, and isoverticine-β-N-oxide isolated from BFW were confirmed. The four alkaloids significantly inhibited cough frequency and increased latent period of cough in mice induced by ammonia. Imperialine and isoverticine showed obviously antitussive activities in a dose-dependent manner. Besides, the four alkaloids markedly enhanced mice's tracheal phenol red output in expectorant assessment and significantly inhibited the development of ear edema in anti-inflammatory evaluation assay. Moreover, significant differences were found between the structure-activity relationships of the four alkaloids.

Conclusions

The four alkaloids exhibited significant antitussive, expectorant and anti-inflammatory activities. We suggest that they may be the active ingredients of BFW. The results of the present study provided evidence for BFW to be used as an antitussive and expectorant Traditional Chinese Medicine (TCM).     

In vivo anti-tussive activity and structural features of a polysaccharide fraction from water extracted Withania somnifera

Aim of the study

Anti-tussive drugs are amongst the most widely used medications worldwide; however no new class of drugs has been introduced into the market for many years. The present study aims at evaluating the structural features and in vivo anti-tussive activity of a polysaccharide fraction from water extracted Withania somnifera.

Materials and methods

Herein, we have analyzed water extracted material of Withania somnifera using chemical, chromatographic, spectroscopic and biological methods.

Results

A polysaccharide fraction (F3) containing arabinosyl, galactosyl and galacturonosyl residues were obtained by anion exchange chromatography of the water extracted material. This polymer is branched and contained (1,5)-/(1,3,5)-linked arabinofuranosyl, (1,3)-/(1,6)-/(1,3,6)-linked galactopyranosyl residues together with small amount of terminal rhamnopyranosyl and terminal arabinofuranosyl residues. Peroral administration of this pectic arabinogalactan in a dose of 50 mg kg⁻¹ body weight (b.w.) decreased the number of cough efforts induced by citric acid in guinea pigs like that of codeine.

Conclusions

This study provides a scientific basis for the past and present ethnomedical uses of this plant.     

In vivo evaluation of the anti-asthmatic,antitussive and expectorant activities of extract and fractions from Elaeagnus pungens leaf

The leaf of Elaeagnus pungens thunb. (Family Elaeagnaceae) has been documented as an effective herb for the treatment of asthma and chronic bronchitis in traditional Chinese medicine. This study was aimed at evaluating the anti-asthmatic, antitussive and expectorant activities in vivo of the ethanolic extract and fractions from the leaf of Elaeagnus pungens. The results showed that the 70% ethanolic extract increased the preconvulsive time of asthma induced by the combination of histamine and acetylcholine chloride in guinea pigs at the medium dose of 1.379 g/kg. The water fraction significantly prolonged the preconvulsive time (P < 0.05) in guinea pigs, lengthened the latent period of cough (P < 0.05) as well as decreased the cough frequency caused by citric acid in guinea pigs (P < 0.01) and enhanced tracheal phenol red output in mice (P < 0.01). Moreover, the petroleum ether fraction significantly reduced the cough frequency induced in guinea pigs (P < 0.01) and improved tracheal phenol red output in mice (P < 0.01). It indicated that the petroleum ether fraction and the water fraction of Elaeagnus pungens leaf were effective on anti-asthmatic, antitussive and expectorant activities, which supplied for further research on chemical constituents and pharmacological mechanisms.     

Antimalarial alkaloids from a Bhutanese traditional medicinal plant Corydalis dubia

Ethnopharmacological relevance

Corydalis dubia is used in Bhutanese traditional medicine as a febrifuge and for treating infections in the blood, liver and bile which correlate to the signs and symptoms of malarial and microbial infections.

Aim of the study

To validate the ethnopharmacological uses of the plant and to discover potential new therapeutic drug leads.

Materials and methods

C. dubia was collected from Bhutan and the alkaloids were obtained using acid–base fractionation and separation by repeated column and preparative plate chromatography. The alkaloids were identified from analysis of their physiochemical and spectroscopic data and were tested for antiplasmodial, antimicrobial and cytotoxicity activities.

Results

A systematic extraction and isolation protocol yielded one new natural product, dubiamine, and seven known isoquinoline alkaloids, scoulerine, cheilanthifoline, protopine, capnoidine, bicuculline, corydecumbine and hydrastine. Among the four alkaloids tested, scoulerine showed the best antiplasmodial activity with IC₅₀ values of 5.4 μM and 3.1 μM against the antifolate sensitive and the multidrug resistant P. falciparum strains: TM4/8.2 and K1CB1, respectively. None of the alkaloids tested showed significant antimicrobial or cytotoxicity activities.

Conclusions

The antiplasmodial test results, of the isolated alkaloid components, are commensurated with the ethnopharmacological uses of this plant.     

Sceptridium ternatum extract exerts antiasthmatic effects by regulating Th1/Th2 balance and the expression levels of leukotriene receptors in a mouse asthma model

Aim of the study

Sceptridium ternatum Lyon (ST), a common Chinese herb, has been used in treatment of allergic asthma and whooping cough. In the present study, we investigated the Th1/Th2 ratio of peripheral blood and mRNA levels of leukotriene receptors after the treatment of ST in allergic asthma mouse model.

Materials and methods

Mouse asthma model was developed by ovalbumin (OVA) sensitization followed by the inhalation of aerosol allergen. Montelukast (10 mg/kg), as a positive control drug, and ST were administrated six days before the OVA sensitization for ten days. Airway responsiveness was evaluated by the Medlab 12.0 biological signal processing system. The ratio of Th1/Th2 cells was determined by flow cytometry. The expression level of Cyslt1 was measured by PCR. Pathological changes of lung tissues were examined by H&E staining.

Results

ST significantly reduced the airway responsiveness, elevated the ratio of Th1/Th2, and decreased Cyslt1 mRNA level in a dose-dependent manner. High-dose ST distinctly prevented the pathological changes of lung tissues.

Conclusion

High-dose ST had the same efficacy as Montelukast in a mouse asthma model, and ST could be a potential anti-asthmatic agent.     

Evaluation of antiallergic and anti-anaphylactic activity of ethanolic extract of Sanseveiria trifasciata leaves (EEST) in rodents

Aim of the study

The leaves and rhizomes of Sansevieria trifasciata are used in folk medicine for treating bronchitis, asthma, cough, snake bite and insect bite etc. The ethanolic extract elicited analgesic, anti-inflammatory and antipyretic activity. Hence, it was decided to study the antiallergic activity of ethanolic extract of S. trifasciata (EEST) on various animal models as well as in vitro conditions, and also to understand possible mechanism of action.

Materials and methods

Ethanolic extract of S. trifasciata leaves (EEST) were prepared by cold maceration followed by concentration and evaporation under reduced pressure on a rotary evaporator to obtain semisolid mass. The various phytoconstituents were analyzed. The acute toxicity study of EEST was carried out in mice. The antiallergic and anaphylactic activities were evaluated using animal models viz. milk induced eosinophilia and leukocytosis, compound 48/80 induced mast cell degranulation, active and passive cutaneous anaphylaxis and histamine induced pedal edema. In addition, EEST effect on Shultz–Dale reaction in sensitized guinea pig ileum in ex vivo and antioxidant activity by free radical scavenging by DPPH method (in vitro) were also studied.

Results

EEST treatment at 100 mg/kg and 200 mg/kg p.o inhibited (a) milk-induced increased eosinophilia, leukocytosis, monocytes and neutrophils. (b) Prevented passive cutaneous and active anaphylactoid reactions. (c) Prevented compound 48/80 induced degranulation of sensitized mesenteric mast cells. (d) Inhibited histamine induced pedal edema formation significantly. EEST pretreatment inhibited Shultz–Dale reaction in guinea pig ileum and also elicited potent antioxidant activity.

Conclusion

Experimental findings demonstrate promising antiallergic and anti-anaphylactic activity of EEST and also elicited potent antioxidant activity. The antiallergic and anti-anphylactic activity might be due to inhibition of release of chemical mediators from mast cells largely by phytoconstituents like steroidal saponins, triterpenoids and flavonoids present in EEST.     

Regulation effects on abnormal glucose and lipid metabolism of TZQ-F,a new kind of Traditional Chinese Medicine

Aim of the study

Based on the recipe of the traditional anti-diabetic formula TZQ, we developed TZQ-F, a new formula including 8 fractions isolated from Red Paeony root, Mulberry leaf, Lotus leaf, Danshen root and Hawthorn leaf with a good quality assurance. The study was aimed at fraction preparation and effects of the fractions on abnormal glucose and lipid metabolism.

Materials and methods

The active fractions were obtained by macroporous resin, ion-exchange resin and polyamide resin column chromatographies. HPLC analyses were used for quality control. In vitro mechanism study included DPPH radical scavenging, AGEs formation inhibition, α-glucosidase inhibition and lipase inhibition, and rats on high-fat diet were used for in vivo study.

Results

In vitro mechanism study showed that among the 8 fractions, three of them had inhibition effects on intestinal disaccharase, three with inhibition effects on lipase, and five with effects of free radical scavenging. In vivo study showed that after 4 weeks of treatment, TZQ-F significantly decreased the levels of serum total cholesterol, TG, glucose, LDL-C and HDL-C in rats on high-fat diet. Consistent with the in vitro and in vivo results, histology study demonstrated that TZQ-F alleviated hepatic steatosis induced by high-fat diet.

Conclusions

TZQ-F possesses the potential regulation effects on abnormal glucose and lipid metabolism.     

Total steroidal alkaloids from Veratrum patulum L. Inhibit platelet aggregation, thrombi formation and decrease bleeding time in rats

Ethnopharmacological relevance

Veratrum patulum L. (Liliaceae) is used as one source of the Chinese traditional drug “Lilu” which has been used in the treatment of aphasia arising from apoplexy, wind type dysentery, headache, etc. for thousands of years.

Aim of the study

To evaluate the antithrombotic effect of Veratrum patulum L. (Liliaceae) total steroidal alkaloids (VpA) and explore the potential mechanisms.

Materials and methods

The antithrombotic effect of VpA was evaluated in two experimental thrombosis models in rat. The potential antithrombotic mechanisms of VpA were explored by determining the coagulation parameters and platelet aggregation induced by various agonists. Cutting-tail rat model was used to evaluate the influence of VpA on bleeding time.

Results

VpA significantly inhibit the formation of arterial and venous thrombosis and showed different inhibitory effect on the platelet aggregation induced by various agonists with the following potency order: collagen > ADP > thrombin. VpA showed no influence on the coagulation parameters in rat. But VpA decreased the cutting-tail bleeding time in rat.

Conclusion

VpA possess antithrombotic effect on venous and arterial thrombosis. The antithrombotic effect of VpA is due to its inhibition to platelet aggregation, especially induced by collagen.     

Identification of the toxic constituents in Rhizoma Coptidis

Aim of the study

Rhizoma Coptidis (Huanglian) is a widely used Traditional Chinese Medicine. However, it causes human as well as animal toxicities. In this study, we aimed to ascertain the toxic constituents in Rhizoma Coptidis.

Materials and methods

The acute toxicity of both the total extract and the alkaloid-rich extract of Rhizoma Coptidis were tested in mice. The dose related tissue concentration of the Rhizoma Coptidis alkaloids in mice was determined using high performance liquid chromatography with ultraviolet detection. The influence of phenobarbital sodium [a non-selective hepatic enzyme (P450) inducer] on the acute toxicity of Rhizoma Coptidis as well as the tissue concentration of the alkaloids was investigated. The cytotoxicity of the Rhizoma Coptidis alkaloids was tested in six cell lines using the MTT assay.

Results

The median acute oral lethal dose of the total extract of Rhizoma Coptidis was 2.95 g/kg in mice. The alkaloid-rich extract was much more toxic than the total extract of Rhizoma Coptidis. Four Rhizoma Coptidis alkaloids were detected in brain, heart, and lung tissues of mice that received the oral total extract of Rhizoma Coptidis. Tissue concentration increased nonlinearly with higher doses. Phenobarbital sodium decreased the tissue concentration of every alkaloid as well as the toxicity of Rhizoma Coptidis. All alkaloids, especially berberine, showed dose and time dependent cytotoxicity.

Conclusions

The toxic constituents of Rhizoma Coptidis were the alkaloids, mainly berberine.     

Assessment of the antidiarrhoeal properties of the aqueous extract, the 80% methanol extract and its soluble fractions of the leaves of Alstonia congensis Engl. (Apocynaceae) in Wistar rats

Aim of the study

To evaluate the antidiarrhoeal properties of Alstonia congensis leaves claimed to be effective for the treatment of diarrhoea by traditional healers during our ethnopharmacological investigation conducted in Kinshasa, Democratic Republic of Congo.

Materials and methods

The aqueous extract (decoction), and the 80% hot methanol extract (Soxhlet extraction) were obtained. This last extract was fractionated. The antidiarrhoeal activity was evaluated using castor oil and magnesium sulphate-induced diarrhoea in animals. The potential antibacterial activity of all samples was also assessed in vitro.

Results

At all oral doses of 100 and 200 mg/kg body weight, all A. congensis samples showed significant and dose-dependent antidiarrhoeal activity in treated Wistar rats characterised by significant increase of onset time and decrease of all other diarrhoeal parameters at various degrees compared to untreated groups in both models. At the highest oral dose of 200 mg/kg bodyweight, the 80% hot methanol and aqueous extracts produced 79.8±2.1% and 78.6±0.5%, and 75.0±2.1% and 71.4±2.1% inhibition of defecation and diarrhoea respectively against castor oil-induced diarrhoea, and 75.0±1.2% and 73.3±1.2% inhibition of diarrhoea respectively against magnesium sulphate-induced diarrhoea. The 80% hot methanol and aqueous detannified extracts showed low activity (42–47% inhibition of defecation and/or diarrhoea in both tests) suggesting that tannins may be responsible for the observed activity. At the same oral doses, the total alkaloid extract, the chloroform soluble fraction rich in alkaloids, the 80% methanol and the alkaline aqueous soluble subfractions produced more than 50% inhibition of defecation and/or diarrhoea in both tests. From the antibacterial testing in vitro, results indicated that all A. congensis samples exhibited an antibacterial activity mainly against bacteria implicated in diarrhoea with MIC and MBC values in the range of 15.6–500 μg/ml. The most active samples were the aqueous (decoction) and the 80% hot methanol dried extracts, the chloroform subfraction rich in alkaloids and the total alkaloid extract (MIC: 15.7–125 μg/ml, MBC: 31.2–250 μg/ml). Proteus varibilis was found to be the most resistant microorganism.

Conclusion

These reported results can partly support and justify the traditional use of extracts from Alstonia congensis leaves for the treatment of diarrhoea in tradittional medicine.     

Antihistaminic and antiallergic actions of extracts of Solanum nigrum berries: Possible role in the treatment of asthma

Ethnopharmacological relevance

Berries of the plant Solanum nigrum Linn (Solanaceae) are used for the treatment of asthma in folk medicine and ancient books.

Aim of study

To evaluate potential of the plant berries in the treatment of asthma.

Materials and methods

Petroleum ether, ethanol and aqueous extracts of S. nigrum berries (50, 100 and 200 mg/kg, i.p.) were screened for the treatment of asthma by the various methods viz. effect on clonidine and haloperidol induced catalepsy, milk-induced leucocytosis and eosinophilia, mast cell stabilizing activity in mice and studies on smooth muscle preparation of guinea pig ileum (in vitro). Active petroleum ether extract was standardized by HPTLC.

Results

The petroleum ether extract of S. nigrum berries inhibited clonidine-induced catalepsy significantly but not haloperidol-induced catalepsy. Petroleum ether extract significantly inhibited increased leukocyte and eosinophil count due to milk allergen and showed maximum protection against mast cell degranulation by clonidine. Petroleum ether extract resisted contraction induced by histamine better than other extracts. All the results are dose dependant. Active petroleum ether extract showed presence of antiasthmatic compound, β-sitosterol.

Conclusion

The petroleum ether extract of S. nigrum berries can inhibits parameters linked to the asthma disease.     

Gastroprotective effect of Senecio candicans DC on experimental ulcer models

Ethnopharmacological relevance

Senecio candicans DC (Asteraceae) is used as a remedy for gastric ulcer and stomach pain in the Nilgiris district, Tamil Nadu for which no scientific evidence exists.

Aim of the study

The present study was performed to evaluate the gastroprotective effects and acute oral toxicity of aqueous leaf extract of Senecio candicans (AESC) in experimental models.

Materials and methods

The antiulcerogenic activity of AESC was performed in two different ulcer models viz., pylorus-ligated model and ethanol-induced model using Wistar albino rats. Acute toxicity study was also performed to get information on the admissible dose for treatment of ulcer. Preliminary phytochemical screening of AESC was performed to find the active principles present, which are thus responsible for the antiulcerogenic activity. DPPH assay was performed to confirm the antioxidant activity of AESC.

Results

The acute toxicity study did not show any mortality up to 2500 mg/kg b.w. of AESC. Both the ulcer models showed gastroprotective effect comparable to that of the standard Omeprazole. The results of antioxidant enzymes, histopathology sections, ATPase and mucus content of gastric secretion showed that several mechanisms are involved in the gastroprotective effect. The preliminary phytochemical screening revealed the presence of alkaloids, flavonoids and steroids in AESC. The DPPH assay confirmed the antioxidant activity of AESC.

Conclusion

The traditional consumption of AESC for the treatment of gastric ulcer is thus true, the antioxidant constituents present in the extract plays a major role in the gastroprotective activity, but since Senecio species are known for the presence of pyrrolizidine alkaloids, a detailed study in future is required to describe the safe dose for a prolonged period.     

HPLC-based activity profiling for antiplasmodial compounds in the traditional Indonesian medicinal plant Carica papaya L

Ethnopharmacological relevance

Leaf decoctions of Carica papaya have been traditionally used in some parts of Indonesia to treat and prevent malaria. Leaf extracts and fraction have been previously shown to possess antiplasmodial activity in vitro and in vivo.

Materials and methods

Antiplasmodial activity of extracts was confirmed and the active fractions in the extract were identified by HPLC-based activity profiling, a gradient HPLC fractionation of a single injection of the extract, followed by offline bioassay of the obtained microfractions. For preparative isolation of compounds, an alkaloidal fraction was obtained via adsorption on cationic ion exchange resin. Active compounds were purified by HPLC–MS and MPLC–ELSD. Structures were established by HR-ESI-MS and NMR spectroscopy. For compounds 5 and 7 absolute configuration was confirmed by comparison of experimental and calculated electronic circular dichroism (ECD) spectroscopy data, and by X-ray crystallography. Compounds were tested for bioactivity in vitro against four parasites (Trypanosoma brucei rhodesiense, Trypanosoma cruzi, Leishmania donovani, and Plasmodium falciparum), and in the Plasmodium berghei mouse model.

Results

Profiling indicated flavonoids and alkaloids in the active time windows. A total of nine compounds were isolated. Four were known flavonols – manghaslin, clitorin, rutin, and nicotiflorin. Five compounds isolated from the alkaloidal fraction were piperidine alkaloids. Compounds 5 and 6 were inactive carpamic acid and methyl carpamate, while three alkaloids 7–9 showed high antiplasmodial activity and low cytotoxicity. When tested in the Plasmodium berghei mouse model, carpaine (7) did not increase the survival time of animals.

Conclusions

The antiplasmodial activity of papaya leaves could be linked to alkaloids. Among these, carpaine was highly active and selective in vitro. The high in vitro activity could not be substantiated with the in vivo murine model. Further investigations are needed to clarify the divergence between our negative in vivo results for carpaine, and previous reports of in vivo activity with papaya leaf extracts.     

Anti-histamine effect of Rubia tibetica, used to treat anaphylaxis caused by tick bites in the Pamir Mountains, Afghanistan

Ethnopharmacological relevance

The roots of Rubia tibetica are chewed as an antidote to anaphylaxis caused by bites of the tick Ornithodoros lahorensis by the Wakhi people in Afghanistan.

Aims of the study

To test whether Rubia tibetica possess anti-histamine effect.

Materials and methods

Water and ethanol extracts of roots of Rubia tibetica were tested for anti-histamine effect on the H₁-receptor in the guinea pig ileum assay. Fixed concentrations of plant extract with increasing concentrations of histamine were examined. Mepyramine was used as control.

Results and conclusion

The ethanol extract of Rubia tibetica showed dose-dependent anti-histamine effect, whereas the water extract had little activity. The chewing of Rubia tibetica roots may alleviate the fatal swelling of the tongue during anaphylaxis.     

The effects of Tabernaemontana divaricata root extract on amyloid β-peptide 25–35 peptides induced cognitive deficits in mice

Ethnophamacological relevance

Tabernaemontana divaricata (TD), a Thai medicinal herb, has been widely used as an analgesic, sedative, or a cough syrup. Moreover, it has been used in traditional rejuvenation remedies as for preventing forgetfulness and improving the memory.

Aim of study

The present study aimed to determine the effect of TD on Aβ25–35 peptides induced cognitive deficits and acetylcholinesterase activity in mice.

Materials and methods

Mice were pretreated with TDE (250, 500 and 1000 mg/kg body weight) for 28 days and then received i.c.v. injection of Aβ25–35 peptides. Cognitive performance was evaluated using the Morris water maze (MWM) and step-down avoidance test. The Ellman's colorimetric method was used to investigate the levels of cortical and hippocampal AChE activity.

Results

Aβ25–35 peptides induced the memory impairment and the increased levels of cortical and hippocampal AChE activity. The consumption of TDE significantly improved the memory impairment and attenuated the brain levels of AChE activity induced by Aβ25–35 peptides.

Conclusions

These findings suggest that subchronic administration of TDE might prevent the Aβ25–35 peptides induced memory deficits by decreasing the AChE activity level. Therefore TDE could potentially be one of nootropic supplements for those elderly people suffering from dementia such as the AD patients.