Antiprotozoal activity of the constituents of Teloxys graveolens

Flavonoids from Piper Species as Promising Antiprotozoal Agents against Giardia intestinalis. Structure-Activity Relationship and Drug-Likeness Studies

Diarrhea diseases caused by the intestinal protozoan parasite Giardia intestinalis are a major global health burden. Moreover, there is an ongoing need for novel anti-Giardia drugs due to drawbacks with currently available treatments. This paper reports on the isolation and structural elucidation of six new flavonoids (1-6), along with twenty-three known ones (7-29) from the Piper species. Their structures were established by spectroscopic and spectrometric techniques. Flavonoids were tested for in vitro antiprotozoal activity against Giardia intestinalis trophozoites. In addition, structure-activity relationship (SAR) and in silico ADME studies were performed to understand the pharmacophore and pharmacokinetic properties of these natural compounds. Eight flavonoids from this series exhibited remarkable activity in the micromolar range. Moreover, compound 4 was identified as having a 40-fold greater antiparasitic effect (IC50 61.0 nM) than the clinical reference drug, metronidazole (IC50 2.5 µM). This antiprotozoal potency was coupled with an excellent selectivity index (SI 233) on murine macrophages and in silico drug-likeness. SAR studies revealed that the substitution patterns, type of functional group, and flavonoid skeleton played an essential role in the activity. These findings highlight flavonoid 4 as a promising candidate to develop new drugs for the treatment of Giardia infections.

Codiaeum variegatum (L.) Rumph. ex A. Juss. (Euphorbiaceae): An overview of its botanical diversity, traditional uses, phytochemistry, pharmacological effects and perspectives towards developing its plant-based products

ETHNOPHARMACOLOGICAL RELEVANCE

Codiaeum variegatum also called miracle shrub, is a plant species constituted of more than 300 cultivars which are mostly used as indoor plants for decoration. However, some of these varieties are used by indigenous populations for the treatment of diarrhoea, stomach ache, external wounds, intestinal worms and ulcers.

AIM OF THE STUDY

This study describes an overview of the botanical diversity, medicinal uses, phytochemical composition of C. variegatum. Then it critically discusses its pharmacological activities versus toxic potential and new perspectives are suggested for the development of its plant-based products.

MATERIALS AND METHODS

A bibliographic assessment of publications on C. variegatum indexed in Google Scholar, PubMed, Science Direct, Scopus, Springer Link, and Web of Science online databases was conducted from 1970 to 2020, and 89 relevant articles related to the botanical diversity (17), traditional uses (22), phytochemical analysis (11), pharmacological activity (31) and toxicity profile (18) of C. variegatum were selected for this review.

RESULTS

Most commonly, it was found that aqueous leaf extracts or decoctions of C. variegatum are used in traditional medicine to treat amoebic dysentery and stomach ache while a bath with root decoction or sap is applied in small quantities on skin related infections. A total of 14 identified and 24 non-identified varieties of C. variegatum were reported for pharmacological activity, and prominent research topics include the anti-amoebic, antimicrobial, antiviral and cytotoxic activities. Alkaloids (3), terpenoids (5) and phenolics (15) were the major compounds identified, and a new antiviral cyanoglucoside was isolated from the sap of C. variegatum. Toxic substances (5-deoxyingenol and phorbol esters) were found in some varieties used as ornamental plants, but the Mollucanum variety used in traditional medicine was found to be safe.

CONCLUSION

The present review revealed that the native variety of C. variegatum (cv. Mollucanum) can be used to treat amoebic dysentery. Alkaloids, terpenoids and phenolic compounds have been characterized in this plant species while other classes of phytochemicals are not yet investigated. The development of new cultivars recommends an in-depth toxicological study before any use. No clinical trial has been reported to date, and further studies are needed to evaluate other claimed medicinal uses. Due to its efficacy and safety, the Mollucanum variety is most likely suitable for the development of a medicine against amoebiasis, which will surely lay the foundation for clinical studies.

Furanocoumarins from Ruta chalepensis with Amebicide Activity

Entamoeba histolytica (protozoan; family Endomoebidae) is the cause of amoebiasis, a disease related to high morbidity and mortality. Nowadays, this illness is considered a significant public health issue in developing countries. In addition, parasite resistance to conventional medicinal treatment has increased in recent years. Traditional medicine around the world represents a valuable source of alternative treatment for many parasite diseases. In a previous paper, we communicated about the antiprotozoal activity in vitro of the methanolic (MeOH) extract of Ruta chalepensis (Rutaceae) against E. histolytica. The plant is extensively employed in Mexican traditional medicine. The following workup of the MeOH extract of R. chalepensis afforded the furocoumarins rutamarin (1) and chalepin (2), which showed high antiprotozoal activity on Entamoeba histolytica trophozoites employing in vitro tests (IC₅₀ values of 6.52 and 28.95 µg/mL, respectively). Therefore, we offer a full scientific report about the bioguided isolation and the amebicide activity of chalepin and rutamarin.

A systematic review of anti-Entamoeba histolytica activity of medicinal plants published in the last 20 years

Amoebiasis has emerged as a major health problem worldwide. It is endemic in the present scenario is different and sub-tropical regions especially in Asia, Latin America and also in Africa. Causative of amoebiasis is a protozoan known as Entamoeba histolytica. We screened all the databases such as PubMed, Science Direct, Medline and Google Scholar by using the keywords ‘anti-Entamoeba histolytica activity of medicinal plants, anti-Entamoeba histolytica activity of herbal drugs, the anti-amoebic activity of natural drugs’. In the present study, we found 7861 articles, where all articles were screened for bias analysis and included 32 full-matching articles in total reporting the use of medicinal plants as a remedy for amoebiasis. Through these articles, we found 42 herbs having anti-amoebic activity. In bias analysis, we also found four articles under high bias risk. In our study, seven medicinal plants were concluded to possess the most potent anti-amoebic activity based on their IC50 value, which was less than 1 μg mL−1. On bias analysis, we found four articles with high bias risk, hence these studies can be repeated for better results.

Antiprotozoal Activity against Entamoeba histolytica of Flavonoids Isolated from Lippia graveolens Kunth

Amebiasis caused by Entamoeba histolytica is nowadays a serious public health problem worldwide, especially in developing countries. Annually, up to 100,000 deaths occur across the world. Due to the resistance that pathogenic protozoa exhibit against commercial antiprotozoal drugs, a growing emphasis has been placed on plants used in traditional medicine to discover new antiparasitics. Previously, we reported the in vitro antiamoebic activity of a methanolic extract of Lippia graveolens Kunth (Mexican oregano). In this study, we outline the isolation and structure elucidation of antiamoebic compounds occurring in this plant. The subsequent work-up of this methanol extract by bioguided isolation using several chromatographic techniques yielded the flavonoids pinocembrin (1), sakuranetin (2), cirsimaritin (3), and naringenin (4). Structural elucidation of the isolated compounds was achieved by spectroscopic/spectrometric analyses and comparing literature data. These compounds revealed significant antiprotozoal activity against E. histolytica trophozoites using in vitro tests, showing a 50% inhibitory concentration (IC₅₀) ranging from 28 to 154 µg/mL. Amebicide activity of sakuranetin and cirsimaritin is reported for the first time in this study. These research data may help to corroborate the use of this plant in traditional Mexican medicine for the treatment of dyspepsia.

Plants used for the treatment of diarrhoea from Mexican flora with amoebicidal and giadicidal activity, and their phytochemical constituents

ETHNOPHARMACOLOGICAL RELEVANCE

Flora of the Mexican region is represented by approximately 30,000 vascular plant species, many of which are used as traditional medicines based on knowledge compiled and refined since ancient times (e.g. Cruz-Badiano and Florentino Codexes). The traditional use of plants as medicines, including the treatment of infectious diseases such as diarrhoea, is generally practiced in communities that are geographically isolated or in human settlements where health services are scarce.

AIM OF THE STUDY

The aim of this review is to evaluate current research advances in the ethnopharmacology and phytochemistry of Mexican medicinal plants exhibiting antiprotozoal activity, used to treat diarrhoea, and to identify the gaps in this research area for future studies.

METHODS

The literature study and compilation of information relied on books and scientific journals from leading electronic databases including Scopus, Springer, SciFinder, ISI Web of Science, PubMed, and Google Scholar; the topics searched for were antiprotozoal activity, followed by Entamoeba histolytica or Giardia lamblia. Ethnopharmacological data were obtained from books regarding medicinal plants and their uses in Mexico as well as from the government databases of "Comisiòn Nacional para el Conocimiento y Uso de la Biodiversidad (CONABIO)" as "NaturaLista" and "EncicloVida".

RESULTS

A total of 80 plant species used in the Mexican traditional medicine for the treatment of diarrhoea have been evaluated as potential sources of antiprotozoal agents against E. histolytica or G. lamblia. From these samples, 150 compounds have been isolated and screened in vitro, including specialized metabolites such as flavonoids and terpenoids as well as semisynthesized derivatives. However, in vivo pharmacological studies on these substances are limited. Additional pharmacological and molecular studies of the most active compounds have also been summarized.

CONCLUSION

Research performed in the past 25 years on specialized metabolites derived from plants with antiprotozoal activity has yielded relevant findings whose results provide evidence-based support for the use of these plants in the traditional medicine of Mexico to treat diarrhoea. Toxicological and clinical trials of standardized extracts and bioactive compounds are proposed as priority future works in this research area. In addition, in vivo assays are required, of more extracts and/or pure compounds. The optimization of the pharmacological properties of the bioactive specialized metabolites through semisynthetic derivatives and computational methods could aid in developing new antiprotozoal phytomedicines and novel drugs for the treatment of these types of infections. Furthermore, elucidation of the mechanism of action of these bioactive compounds through pharmacological and molecular studies are also necessary.

Chemistry and Biology of Selected Mexican Medicinal Plants

Herbal medicines are an integral element of alternative medical care in Mexico, and the best testimony to their efficacy and cultural value is their persistence in contemporary Mexican marketplaces where the highest percentages of medicinal and aromatic plants are sold. This chapter summarizes current trends in research on medicinal plants in Mexico, with emphasis on work carried out at the authors' laboratories. The most relevant phytochemical and pharmacological profiles of a selected group of plants used widely for treating major national health problems are described.From this contribution, it is evident that in the last five decades a significant amount of research on medicinal plants has been performed by Mexican scientists. Such efforts have led to the publication of many research papers in noted peer-reviewed journals and technical books. The isolation and structural characterization of hundreds of bioactive secondary metabolites have been accomplished, and most importantly, these studies have tended to support the ethnomedical uses of many different species. A multidisciplinary approach for investigating these plants has led to an increased emphasis on areas such as phytopharmacology, phytotoxicology, quality control, regulation, and conservation issues for these valuable resources. The medicinal plants analyzed so far have shown a very broad chemical diversity of their constituents, which have a high potential for exhibiting novel mechanistic effects biologically. The chapter shows also that there is need to conduct additional clinical studies on herbal drugs, in particular because the longstanding traditional evidence for their safety is not always sufficient to assure their rational use. There is also need to move to "omics" approaches for investigating the holistic effect and the influence of groups of phytochemicals on the whole organism. Mexican scientists may be expected to have bright prospects in this regard, which will imbue medicinal plant research with a new dynamism in the future.

Evaluation of Cytotoxic Effect of Different Extracts of Seidlitzia rosmarinus on HeLa and HepG2 Cell Lines

Background:

Seidlitzia rosmarinus which is commonly called “Oshnan” or “Eshnan” in Persian belongs to Chenopodiaceae family. Conventionally, it is believed that this plant is toxic. This study was aimed to evaluate the cytotoxic effect of S. rosmarinus against HeLa and HepG₂ cell lines.

Materials and Methods:

S. rosmarinus was collected from the desert near Yazd, Iran. Hexane, chloroform, chloroform/methanol (9:1), and butanol extracts of aerial parts of S. rosmarinus were prepared. Doxorubicin and dimethyl sulfoxide 10% were used as positive and negative control, respectively. The cytotoxic activity was measured using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay.

Results:

All extracts significantly and concentration dependently reduced viability of HeLa and HepG2 cells. Hexane, chloroform, and butanol extracts at doses of 200, 500, 750, and 1000 μg/ml significantly reduced HeLa cell viability (P < 0.05). Chloroform/methanol extract at doses of 100–500 μg/ml significantly reduced HeLa cell viability (P < 0.05). Hexane, chloroform, and butanol extracts at doses of 500, 750, and 1000 μg/ml significantly reduced HepG2 cell viability (P < 0.05). Chloroform/methanol extract at doses of 200, 300, 400, and 500 μg/ml significantly reduced HepG cell viability (P < 0.05). The most cytotoxic extract was chloroform/methanol extract in both cell lines. Furthermore, in the both cell lines, the second potent extract was chloroform extract.

Conclusions:

It can be concluded from the findings of this study that S. rosmarinus is a good candidate for further study to find new cytotoxic agents. Phytochemical investigation on chloroform/methanol extract and their structures is recommended.

Vasodilator Activity of Compounds Isolated from Plants Used in Mexican Traditional Medicine

Arterial hypertension is one of the main risk factors in the development of cardiovascular diseases. Therefore, it is important to look for new drugs to treat hypertension. In this study, we carried out the screening of 19 compounds (triterpenes, diterpenes, sesquiterpenes, lignans, and flavonoids) isolated from 10 plants used in Mexican traditional medicine to determine whether they elicited vascular smooth muscle relaxation and, therefore, could represent novel anti-hypertension drug candidates. The vasorelaxant activity of these compounds was evaluated on the isolated rat aorta assay and the results obtained from this evaluation showed that three compounds induced a significant vasodilatory effect: meso-dihydroguaiaretic acid [half maximal effective concentration (EC₅₀), 49.9 ± 11.2 µM; maximum effect (Emax), 99.8 ± 2.7%]; corosolic acid (EC₅₀, 108.9 ± 6.7 µM; Emax, 96.4 ± 4.2%); and 5,8,4′-trihydroxy-3,7-dimethoxyflavone (EC₅₀, 122.3 ± 7.6 µM; Emax, 99.5 ± 5.4%). Subsequently, involvement of the NO/cyclic guanosine monophosphate (cGMP) and H₂S/ATP-sensitive potassium channel (K_ATP) pathways on the vasodilator activity of these compounds was assessed. The results derived from this analysis showed that the activation of both pathways contributes to the vasorelaxant effect of corosolic acid. On the other hand, the vasodilator effect of meso-dihydroguaiaretic acid and 5,8,4′-trihydroxy-3,7-dimethoxyflavone, partly involves stimulation of the NO/cGMP pathway. However, these compounds also showed an important endothelium-independent vasorelaxant effect, whose mechanism of action remains to be clarified. This study indicates that meso-dihydroguaiaretic acid, corosolic acid, and 5,8,4′-trihydroxy-3,7-dimethoxyflavone could be used as lead compounds for the synthesis of new derivatives with a higher potency to be developed as drugs for the prevention and treatment of cardiovascular diseases.

Antinociceptive pharmacological profile of Dysphania graveolens in mouse

This work evaluates the potential antinociceptive activity of Dysphania graveolens, traditional medicinal plant used in Mexico to treat stomach pain. A CH₂Cl₂-MeOH extract, infusion and essential oil from aerial parts of Dysphania graveolens were evaluated in hot plate and writhing tests in mice. The metabolites pinostrobin, pinocembrin and chrysin were isolated from the Dysphania graveolens infusion; next, they were evaluated in both nociceptive tests. To confirm the antinociceptive activity and explore the possible participation of opioid, GABA and serotonin receptors in the pharmacological mechanism, a formalin test was used. Oral administration of Dysphania graveolens CH₂Cl₂-MeOH extract, infusion and essential oil (31-316mg/kg) produced an antinociceptive response to thermic and chemical algesic stimuli. Essential oil was the most active partition of this plant. In addition, the secondary metabolites pinostrobin, pinocembrin and chrysin possess a significant antinociceptive effect. This response was confirmed by the formalin test for the CH₂Cl₂-MeOH extract of Dysphania graveolens and chrysin. In both cases, the antinociceptive activity was reverted in the presence of naltrexone, flumazenil and bicuculline antagonists. The 5-HT_2A/2C receptors did not participate in the antinociceptive response of this plant. The overall information tends to support the efficacy of Dysphania graveolens as an analgesic and its cultural use in abdominal pain.

Reverse Pharmacology and Drug Discovery: Artemisia annua and Its Anti-HIV Activity

There are various ways in which new drugs can be developed. One approach is in silico drug design based on our existing knowledge of the biology of a specific disease and the specific target site binding chemistry. Based on this knowledge, a range of molecules will be designed and synthesised after which they will be tested in in vitro bioassays for activity and toxicity. The best candidates, called lead compounds, will then be “fine-tuned” by chemical derivatisation in order to improve their activity and/or to reduce their toxicity. Lead compounds are then tested in various animal models before entering clinical trials in people. Another approach is to screen a large number of biological samples (plants, bacteria and fungi) for activity against a specific disease. Any active extract, consisting of many compounds, will be fractionated by chromatographic techniques, and each fraction will be tested for in vitro activity. Active fractions will again be fractionated until the active compound is identified. This process, also called bioguided fractionation, can go through a number of fractionation cycles before the active compound is identified. The active compound will be chemically derivatised in order to improve its properties before in vivo animal studies will be conducted. Based on these test results, the most promising lead compounds will then be tested in clinical trials in people. There are however a number of shortcomings with both approaches. It is expensive, time consuming, makes use of in vitro bioassays and it suffers from a very low success rate. Due to these shortcomings, it is currently estimated that the development of one new drug costs around $1–1.5 billion, simply because so many lead compounds fail during clinical trials. Keeping these high costs in mind, one would think that all registered drugs are effective and importantly non-toxic. Unfortunately, this is not the case, as there are a number of drugs currently on the market that are causing severe side effects and whose efficacy should be questioned. This holds true particularly for cancer chemotherapeutics. It was estimated that cancer chemotherapy improves the average 5-year survival rate of patients (for all cancer types) by only 2 % (Morgan et al. 2004). Another relatively unknown fact is that each year, 200,000 people die in the EU due to adverse drug reactions (all types of drugs), highlighting the severe shortcomings of the drug development and drug licensing pipelines (Archibald and Coleman 2012). To put this into perspective, there are a large number of drugs that work perfectly well and are safe to use, but we have to concede that our approach to drug discovery and our overall approach to health care suffers from some major problems.

The complexity of medicinal plants: the traditional Artemisia annua formulation, current status and future perspectives

ETHNOPHARMACOLOGICAL RELEVANCE

Artemisia annua has a long tradition of use for the treatment of intermittent fevers which we now relate to malarial infections. The active principle artemisinin has been isolated from Artemisia annua and today forms the backbone of the global fight against malaria. The traditionally prepared Artemisia annua formulation is however still being used on a global scale for the treatment of malaria, and it is claimed that its action is superior to the single purified drug. Artemisia annua is therefore on the forefront of the heated debate between the single drug-single target approach of western based medicine and the holistic approach of traditional medicinal systems. This review aims to highlight the complexities we face in the general study of medicinal plants at the hand of three levels of complexity. These levels consist of (a) the chemistry of the medicinal plant, (b) the influence of the preparation method on the chemistry of the final formulation and (c) the influence of metabolism on the chemistry of the formulation. We also aim to provide an up-to-date report on all scientific work that has been conducted and published in English on the traditional formulation of Artemisia annua.

MATERIALS AND METHODS

All English scientific literatures published until the first quarter of 2013 were retrieved from well-known scientific databases (Scifinder scholar, Web of Science, PubMed, Google scholar) and Non-governmental organisations active in this field were consulted. A draft version of this manuscript was sent to the African office of the World Health Organisation (WHO), and to the Non-governmental organisations "Action Médicine Naturelle" (ANAMED) and "Iwerliewen fir bedreete Volleker - Réseau belgo-luxembourgeois pour la valorisation des herbes médicinales" (IFBV-BELHERB) for comments.

RESULTS

Very little scientific work has been conducted on the Artemisia annua formulation. The available literature contains many discrepancies which are unfortunately selectively being used by the two different sides in this debate to further their arguments. On one side of the argument we have the low content of artemisinin in Artemisia annua, the low bioavailability of artemisinin when the traditional formulation is administered and the high levels of recrudescence, which are being emphasised, while on the other side the possible role of synergism and prodrugs are being highlighted. This review reports that there are still too many gaps in our existing knowledge to provide conclusive evidence for either of the two sides of the argument.

CONCLUSIONS

Much more research is needed into Artemisia annua formulations. We stand to gain invaluable knowledge into how traditional medicinal plant works, discover the identities of new active compounds (which can be used against other diseases such as HIV, diarrhoea, and cancer) and possibly bring both sides of this debate closer together.

HPLC determination of the major active flavonoids and GC-MS analysis of volatile components of Dysphania graveolens (Amaranthaceae)

INTRODUCTION

Dysphania graveolens is used mainly in Mexican traditional medicine against gastrointestinal ailments. Previous investigations revealed that its flavonoids are important active principles; however, there is not a reliable and accurate analytical method for determining these compounds in the crude drug or preparations of the plant. In addition, its volatile chemical composition remains unknown.

OBJECTIVE

The main goals were to develop a validated HPLC method for quantifying the active flavonoids (pinostrobin (1), pinocembrin (2) and chrysin (3)) of D. graveolens and to establish its volatile composition.

METHODOLOGY

Separation was carried out on a Licrospher100 RP18 column with a linear gradient acetonitrile 0.1% formic acid and aqueous 0.1% formic acid. Accuracy was determined by spiking the crude drug with the standards, the recoveries were between 99% and 101%. A systematic description of the volatile components of D. graveolens was assessed via GC-MS using headspace solid-phase microextraction (HS-SPME) and hydrodistillation extraction methods.

RESULTS

The developed HPLC method represented a powerful technique for the quality control of D. graveolens allowing the quantification of the three active flavonoids. For each compound a linear response was evaluated within the range of 0.5-2.0 mg/mL for pinostrobin (1), 0.25-1.25 mg/mL for pinocembrin (2) and 0.05-0.5 mg/mL for chrysin (3). According to SPME the major components in D. graveolens were p-cymene (84.85%) and eucalyptol (11.26%). On the other hand, the essential oil had eucalyptol (42.89%) and p-cymene (16.51%) and did not contain ascaridol. Thus the most relevant volatile components in the species were monoterpenoids.

3,5-Dicaffeoylquinic acid isolated from Artemisia argyi and its ester derivatives exert anti-leucyl-tRNA synthetase of Giardia lamblia (GlLeuRS) and potential anti-giardial effects

An aqueous ethanol extract of Artemisia argyi inhibited the aminoacylation activity of LeuRS from Giardia lamblia (GlLeuRS). The bioassay-guided fractionation of the extract led to the isolation of 3,5-dicaffeoylquinic acid (1), with an IC₅₀ of 5.82 μg/mL. The ester derivatives of 1 were also found to possess strong anti-GlLeuRS effects, with IC₅₀ values of 1.79, 5.51 and 2.56 μg/mL respectively. Anti-giardial assay showed that the derivatives, especially 3,5-dicaffeoylquinic acid propyl ester (4) (IC₅₀=4.62 μg/mL), were effective at killing G. lamblia.

In vitro activity of the F-6 fraction of oregano against Giardia intestinalis

Giardiosis is a neglected parasitic disease that produces diarrhoea and different degrees of malabsorption in humans and animals. Its treatment is based on derivatives of 5-nitroimidazoles, benzimidazoles, nitrofuranes, acridine and nitrotiazoles. These drugs produce undesirable secondary effects, ranging from a metallic taste in the mouth to genetic damage and the selection of resistant strains; therefore, it is necessary to develop new therapeutic alternatives. We demonstrated that a 2-h treatment with 2·87 μg ml(-1) of fraction 6 of Lippia graveolens (F-6) was sufficient to kill half of an experimental Giardia intestinalis (Syn. G. duodenalis, G. lamblia) population, based on the reduction of MTT-tetrazolium salt levels. F-6 breaks the nuclear envelope and injures the ventral suckling disc. The major compounds of F-6 were characterized as naringenin, thymol, pinocembrin and traces of compounds not yet identified. The results suggest that Lippia is a potential source to obtain compounds with anti-Giardia activity. This knowledge is an important starting point to develop new anti-giardial drugs. Future studies will be required to establish the efficacy of F-6 in vivo using an animal model.

Differential effectiveness of berry polyphenols as anti-giardial agents

Following previous work on the anti-giardial effect of blueberry polyphenols, a range of polyphenol-rich extracts from berries and other fruits was screened for their ability to kill Giardia duodenalis, an intestinal parasite of humans. Polyphenol-rich extracts were prepared from berries using solid-phase extraction and applied to trophozoites of Giardia duodenalis grown in vitro. All berry extracts caused inhibition at 166 μg gallic acid equivalents (GAE)/ml phenol content but extracts from strawberry, arctic bramble, blackberry and cloudberry were as effective as the currently used drug, metronidazole, causing complete trophozoite mortality in vitro. Cloudberry extracts were found to be the most effective causing effectively complete trophozoite mortality at 66 μg GAE/ml. The polyphenol composition of the more effective berry extracts suggested that the presence of ellagitannins could be an important factor. However, the potency of cloudberry could be related to high ellagitannin content but also to the presence of substantial amounts of unconjugated p-coumaric acid and benzoic acid. These in vitro effects occur at concentrations easily achievable in the gut after berry ingestion and we discuss the likelihood that berry extracts could be effective anti-giardial agents in vivo.

Simultaneous determination of eleven major flavonoids in the pollen of Typha angustifolia by HPLC-PDA-MS

INTRODUCTION

The pollen of Typha angustifolia L. has been used for the treatment of dysmenorrhea, stranguria and metrorrhagia. Flavonoids are major active compounds in this pollen and their quantification is important for its quality control.

OBJECTIVE

To establish an HPLC-PDA-MS method for simultaneous determination of the 11 majority flavonoids in the pollen of T. angustifolia.

METHODOLOGY

The optimal condition of separation was achieved on a reversed-phase C₁₈ column with gradient elution of acetonitrile and 0.05% formic acid (v/v) at a flow-rate of 0.8 mL/min; the column temperature was set at 35 °C.

RESULTS

All calibration curves showed good linear regression (r²  > 0.9992). The method provided good accuracy, precision, recovery and sensitivity for the quantification of the 11 compounds analysed.

CONCLUSION

The HPLC method established is appropriate for the quality assurance of the pollen of T. angustifolia.

Efficient microwave-assisted prenylation of pinostrobin and biological evaluation of its derivatives as antitumor agents

Pinostrobin (5-hydroxy-7-methoxyflavanone) obtained in relatively large amounts from fingerroot (Boesenbergia pandurata) was converted to its C-6 and C-8 prenylated derivatives. The Mitsunobu reaction, europium(III)-catalyzed Claisen-Cope rearrangement, and Claisen reaction coupled with cross-metathesis were used as the key steps. Using a sealed-vessel microwave reactor, the Mitsunobu and Claisen/Cope reactions occurred smoothly with short reaction times and in satisfactory yields. The target compounds and five new intermediary substances showed cytotoxic activity toward SK-BR-3, MCF-7, PC-3, and Colo-320DM human tumor cell lines, and all of them had significantly lower IC(50) (microM) values than pinostrobin.

Giardia lamblia: The effects of extracts and fractions from Mentha x piperita Lin. (Lamiaceae) on trophozoites

Giardia lamblia is a parasite that causes giardiasis in humans and other mammals. The common treatment includes different classes of drugs, which were described to produce unpleasant side effects. Mentha x piperita, popularly known as peppermint, is a plant that is frequently used in the popular medicine to treat gastrointestinal symptoms. We examined the effects of crude extracts and fractions from peppermint against G. lamblia (ATCC 30888) on the basis of trophozoite growth, morphology and adherence studies. The methanolic, dichloromethane and hexanic extracts presented IC(50) values of 0.8, 2.5 and 9.0microg/ml after 48h of incubation, respectively. The aqueous extract showed no effect against the trophozoites with an IC(50)>100microg/ml. The aqueous fraction presented a moderate activity with an IC(50) of 45.5microg/ml. The dichloromethane fraction showed the best antigiardial activity, with an IC(50) of 0.75microg/ml after 48h of incubation. The morphological and adhesion assays showed that this fraction caused several alterations on plasma membrane surface of the parasite and inhibited the adhesion of G. lamblia trophozoites. Cytotoxic assays showed that Mentha x piperita presented no toxic effects on the intestinal cell line IEC-6. Our results demonstrated antigiardial activity of Mentha x piperita, indicating its potential value as therapeutic agent against G. lamblia infections.

In vitro susceptibility of Entamoeba histolytica and Giardia lamblia to plants used in Mexican traditional medicine for the treatment of gastrointestinal disorders

In our search for new antiprotozoal chemotherapy, we collected a selection of 26 plants used in Mexican traditional medicine for the treatment of gastrointestinal disorders. Methanolic extracts of these species were screened for their antiprotozoal activity against Entamoeba histolytica and Giardia lamblia trophozoites using in vitro tests. Among the tested extracts, the derivates of following species showed selectivity and significant antiprotozoal activity: Chiranthodendron pentadactylon, Annona cherimola and Punica granatum were the most active on Entamoeba histolytica with IC50 < 30 microg/ml. Dorstenia contrajerva, Senna villosa and Ruta chalepensis were the most active toward Giardia lamblia with IC50 < 38 microg/ml. The potency of Chiranthodendron pentadactylon (IC50 2.5 microg/ml) on Entamoeba histolytica was close that of to emetine, but far less than metronidazole, drugs used as control. The results of the antiprotozoal screening support the popular uses of the studied species for the treatment of diarrhoea and dysentery in Mexican traditional medicine.

Cytotoxicity and in vitro susceptibility of Entamoeba histolytica to Morinda morindoides leaf extracts and its isolated constituents

An aqueous decotion (dried extract), an 80% MeOH extract from Morinda morindoides leaves, and 10 flavonoids and 4 iridoids isolated from the 80% MeOH extract were evaluated in vitro for their potential antiamoebic activity and their cytotoxic effect against MT-4 cells. Results indicated that the aqueous decoction and the 80% MeOH extract exhibited an interesting antiamoebic activity with IC(50) values of 3.1 +/- 1.7 and 1.7 +/- 0.6 microg/ml, respectively. Apigenin-7-O-glucoside and luteolin-7-O-glucoside exhibited a moderate antiamoebic activity with IC(50) values of 22.3 +/- 3.2 and 37.4 +/- 2.7 microg/ml, respectively. Kaempferol (IC(50) = 10.3 +/- 2.3 microg/ml), apigenin (IC(50) = 12.7 +/- 4.3 microg/ml), and luteolin (IC(50) = 17.8 +/- 4.3 microg/ml) showed a more pronounced activity than their corresponding glycosides. All tested iridoids displayed a very good activity with IC(50) values less than 10 microg/ml. The most active iridoids were epoxygaertneroside (IC(50) = 1.3 +/- 0.4 microg/ml) and methoxygaertneroside (IC(50) = 2.3. +/- 0.7), followed by gaertneroside and gaertneric acid with IC(50) values of 4.3 +/- 1.8 and 7.1 +/- 1.4 microg/ml, respectively. Except quercetin and quercetin-7,4'-dimethylether which have shown a cytotoxic effect with IC(50) ranging from 14 to 22 microg/ml. No correlation could be deduced between the observed antiamoebic and cytotoxic activity of these tested samples. A structure-activity relationship for isolated compounds is discussed. These findings support the medicinal report for the traditional use of Morinda morindoides leaves for the treatment of amoebiasis.