Antigiardial and immunostimulatory effect of Piper longum on giardiasis due to Giardia lamblia

Computational investigation of phytochemicals identified from medicinal plant extracts against tuberculosis

Tuberculosis (TB) is still one of the world's most challenging infectious diseases and the emergence of drug-resistant Mycobacterium tuberculosis poses a significant threat to the treatment of TB. Identifying new medications based on local traditional remedies has become more essential. Gas Chromatography-Mass spectrometry (GC-MS) (Perkin-Elmer, MA, USA) was used to identify potential bioactive components in Solanum surattense, Piper longum, and Alpinia galanga plants sections. The fruits and rhizomes' chemical compositions were analyzed using solvents like petroleum ether, chloroform, ethyl acetate, and methanol. A total of 138 phytochemicals were identified, further categorized and finalized with 109 chemicals. The phytochemicals were docked with selected proteins (ethA, gyrB, and rpoB) using AutoDock Vina. The top complexes were selected and preceded with molecular dynamics simulation. It was found that the rpoB-sclareol complex is very stable, which means it could be further explored. The compounds were further studied for ADMET (Absorption, Distribution, Metabolism, Excretion, and Toxicity) properties. Sclareol has obeyed all the rules and it might be a potential chemical to treat TB.Communicated by Ramaswamy H. Sarma.

Piper longum L.: A comprehensive review on traditional uses, phytochemistry, pharmacology, and health-promoting activities

Piper longum (family Piperaceae), commonly known as "long-pepper" or "Pippali" grows as a perennial shrub or as an herbaceous vine. It is native to the Indo-Malaya region and widely distributed in the tropical and subtropical world including the Indian subcontinent, Sri Lanka, Middle-East, and America. The fruits are mostly used as culinary spice and preservatives and are also a potent remedy in various traditional medicinal systems against bronchitis, cough, cold, snakebite, and scorpion-sting and are also used as a contraceptive. Various bioactive-phytochemicals including alkaloids, flavonoids, esters, and steroids were identified from the plant extracts and essential oils from the roots and fruits were reported as antimicrobial, antiparasitic, anthelminthic, mosquito-larvicidal, antiinflammatory, analgesic, antioxidant, anticancer, neuro-pharmacological, antihyperglycaemic, hepato-protective, antihyperlipidaemic, antiangiogenic, immunomodulatory, antiarthritic, antiulcer, antiasthmatic, cardioprotective, and anti-snake-venom agents. Many of its pharmacological properties were attributed to its antioxidative and antiinflammatory effects and its ability to modulate a number of signalling pathways and enzymes. This review comprehensively encompasses information on habit, distribution, ethnobotany, phytochemistry, and pharmacology of P. longum in relation to its medicinal importance and health benefits to validate the traditional claims supported by specific scientific experiments. In addition, it also discusses the safety and toxicity studies, application of green synthesis and nanotechnology as well as clinical trials performed with the plant also elucidating research gaps and future perspectives of its multifaceted uses.

Herbal plants as immunity modulators against COVID-19: A primary preventive measure during home quarantine

The novel coronavirus or severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) is a deadly virus which has spread globally and claimed millions of lives. This novel virus transmits mainly through droplets and close human contact. It’s impact in different countries varies depending on geographical location, climatic conditions, food habits, and cultural activities. Several precautionary measures, as well as many medicines, are applied in different combinations to limit the spread of infection. This results in a preliminary relief of people infected in the first stage of infection. An alternative approach has been introduced which proposes natural herbs, which have minimal or no side effects, and improve overall immunity. Some essential herbs with their immunomodulatory effects are mentioned in this article along with suggestions for improved immunity and protection.

Indian Medicinal Plants and Formulations and Their Potential Against COVID-19-Preclinical and Clinical Research

The cases of COVID-19 are still increasing day-by-day worldwide, even after a year of its first occurrence in Wuhan city of China. The spreading of SARS-CoV-2 infection is very fast and different from other SARS-CoV infections possibly due to structural differences in S proteins. The patients with severe diseases may die due to acute respiratory distress syndrome (ARDS) caused by systemic inflammatory reactions due to the excessive release of pro-inflammatory cytokines and chemokines by the immune effector cells. In India too, it is spreading very rapidly, although the case fatality rate is below 1.50% (https://www.statista.com), which is markedly less than in other countries, despite the dense population and minimal health infrastructure in rural areas. This may be due to the routine use of many immunomodulator medicinal plants and traditional AYUSH formulations by the Indian people. This communication reviews the AYUSH recommended formulations and their ingredients, routinely used medicinal plants and formulations by Indian population as well as other promising Indian medicinal plants, which can be tested against COVID-19. Special emphasis is placed on Indian medicinal plants reported for antiviral, immunomodulatory and anti-allergic/anti-inflammatory activities and they are categorized for prioritization in research on the basis of earlier reports. The traditional AYUSH medicines currently under clinical trials against COVID-19 are also discussed as well as furtherance of pre-clinical and clinical testing of the potential traditional medicines against COVID-19 and SARS-CoV-2. The results of the clinical studies on AYUSH drugs will guide the policymakers from the AYUSH systems of medicines to maneuver their policies for public health, provide information to the global scientific community and could form a platform for collaborative studies at national and global levels. It is thereby suggested that promising AYUSH formulations and Indian medicinal plants must be investigated on a priority basis to solve the current crisis.

Preventive aspect of ayurveda and yoga towards newly emerging disease COVID-19

The ongoing coronavirus pandemic is caused by severe acute respiratory syndrome coronavirus 2 (SARS CoV 2) and unique in various facets. The earlier experience from the past severe acute respiratory syndrome (SARS) epidemics seem to be insufficient and there is need for better strategies in public health and medical care. Ayurved & Yog are well known for their preventive and therapeutic aspect, but not getting utilized properly for prevention of Covid 19 crisis which may also be helpful as supportive therapy along with current line of management. This paper is aimed at unrevealing the role of Ayurved and Yoga guidelines established by Department of AYUSH for prevention from SARS-CoV-2 by providing help to improving the quality of supportive/prophylactic therapy in relation with their immunity.

The protective effect of piperine against isoproterenol-induced inflammation in experimental models of myocardial toxicity

Myocardial infarction (MI) eventually exacerbates inflammatory response due to the release of inflammatory and pro-inflammatory factors. The aim of this study is to explore the protective efficacy of piperine supplementation against the inflammatory response in isoproterenol (ISO)-induced MI. Masson Trichome staining was executed to determine myocardial tissue architecture. Immunohistochemistry was performed for IL-6, TNF-α. RT-PCR studies were performed to ascertain the gene expression of IL-6, TNF-α, iNOS, eNOS, MMP-2, MMP-9, and collagen-III. Western blotting was performed to determine expression of HIF-1α, VEGF, Nrf-2, NF-ƙB, Cox-2, p-38, phospho-p38, ERK-1/2, phospho-ERK-1/2, and collagen-I. HIF-1α, VEGF, and iNOS expression were significantly upregulated with concomitant decline in eNOS expression in the heart myocardial tissue of rats received ISO alone whereas piperine pretreatment prevented these changes in ISO administered rats. Current results revealed ROS-mediated activation of MAPKs, namely, p-p38, p-ERK1/2 in the heart tissue of ISO administered group. Piperine pretreatment significantly prevented these changes in ISO treated group. NF-κB is involved in the modulation of gene expressions responsible for tissue repair. ISO-induced NF-κB-p65 expression was significantly reduced in the group pretreated with piperine and mitigated extent of myocardial inflammation. A significant increase in cardiac fibrosis upon ISO treatment was reported due to the increased hydroxyproline content, MMP-2 & 9 and upregulation of collagen-I protein compared to control group. All these cardiac hypertrophy markers were decreased in 'piperine pretreated ISO administered group' compared to group received ISO injection. Current findings concluded that piperine as a nutritional intervention could prevent inflammation of myocardium in ISO-induced MI.

Food as medicine: A possible preventive measure against coronavirus disease (COVID-19)

The recent and ongoing outbreak of coronavirus disease (COVID‐19) is a huge global challenge. The outbreak, which first occurred in Wuhan City, Hubei Province, China and then rapidly spread to other provinces and to more than 200 countries abroad, has been declared a global pandemic by the World Health Organization. Those with compromised immune systems and/or existing respiratory, metabolic or cardiac problems are more susceptible to the infection and are at higher risk of serious illness or even death. The present review was designed to report important functional food plants with immunomodulatory and anti‐viral properties. Data on medicinal food plants were retrieved and downloaded from English‐language journals using online search engines. The functional food plants herein documented might not only enhance the immune system and cure respiratory tract infections but can also greatly impact the overall health of the general public. As many people in the world are now confined to their homes, inclusion of these easily accessible plants in the daily diet may help to strengthen the immune system and guard against infection by SARS‐CoV‐2. This might reduce the risk of COVID‐19 and initiate a rapid recovery in cases of SARS‐CoV‐2 infection.

Potential Role of Plant Extracts and Phytochemicals Against Foodborne Pathogens

Foodborne diseases are one of the major causes of morbidity and mortality, especially in low-income countries with poor sanitation and inadequate healthcare facilities. The foremost bacterial pathogens responsible for global outbreaks include Salmonella species, Campylobacter jejuni, Escherichia coli, Shigella sp., Vibrio, Listeria monocytogenes and Clostridium botulinum. Among the viral and parasitic pathogens, norovirus, hepatitis A virus, Giardia lamblia, Trichinella spiralis, Toxoplasma and Entamoeba histolytica are commonly associated with foodborne diseases. The toxins produced by Staphylococcus aureus, Bacillus cereus and Clostridium perfringens also cause these infections. The currently available therapies for these infections are associated with various limited efficacy, high cost and side-effects. There is an urgent need for effective alternative therapies for the prevention and treatment of foodborne diseases. Several plant extracts and phytochemicals were found to be highly effective to control the growth of these pathogens causing foodborne infections in in vitro systems. The present review attempts to provide comprehensive scientific information on major foodborne pathogens and the potential role of phytochemicals in the prevention and treatment of these infections. Further detailed studies are necessary to evaluate the activities of these extracts and phytochemicals along with their mechanism of action using in vivo models.

Recent Advances in the Discovery of Novel Antiprotozoal Agents

Parasitic diseases have serious health, social, and economic impacts, especially in the tropical regions of the world. Diseases caused by protozoan parasites are responsible for considerable mortality and morbidity, affecting more than 500 million people worldwide. Globally, the burden of protozoan diseases is increasing and is been exacerbated because of a lack of effective medication due to the drug resistance and toxicity of current antiprotozoal agents. These limitations have prompted many researchers to search for new drugs against protozoan parasites. In this review, we have compiled the latest information (2012-2017) on the structures and pharmacological activities of newly developed organic compounds against five major protozoan diseases, giardiasis, leishmaniasis, malaria, trichomoniasis, and trypanosomiasis, with the aim of showing recent advances in the discovery of new antiprotozoal drugs.

Piper Species: A Comprehensive Review on Their Phytochemistry, Biological Activities and Applications

Piper species are aromatic plants used as spices in the kitchen, but their secondary metabolites have also shown biological effects on human health. These plants are rich in essential oils, which can be found in their fruits, seeds, leaves, branches, roots and stems. Some Piper species have simple chemical profiles, while others, such as Piper nigrum, Piper betle, and Piper auritum, contain very diverse suites of secondary metabolites. In traditional medicine, Piper species have been used worldwide to treat several diseases such as urological problems, skin, liver and stomach ailments, for wound healing, and as antipyretic and anti-inflammatory agents. In addition, Piper species could be used as natural antioxidants and antimicrobial agents in food preservation. The phytochemicals and essential oils of Piper species have shown strong antioxidant activity, in comparison with synthetic antioxidants, and demonstrated antibacterial and antifungal activities against human pathogens. Moreover, Piper species possess therapeutic and preventive potential against several chronic disorders. Among the functional properties of Piper plants/extracts/active components the antiproliferative, anti-inflammatory, and neuropharmacological activities of the extracts and extract-derived bioactive constituents are thought to be key effects for the protection against chronic conditions, based on preclinical in vitro and in vivo studies, besides clinical studies. Habitats and cultivation of Piper species are also covered in this review. In this current work, available literature of chemical constituents of the essential oils Piper plants, their use in traditional medicine, their applications as a food preservative, their antiparasitic activities and other important biological activities are reviewed.

A census of P. longum's phytochemicals and their network pharmacological evaluation for identifying novel drug-like molecules against various diseases, with a special focus on neurological disorders

Piper longum (P. longum, also called as long pepper) is one of the common culinary herbs that has been extensively used as a crucial constituent in various indigenous medicines, specifically in traditional Indian medicinal system known as Ayurveda. For exploring the comprehensive effect of its constituents in humans at proteomic and metabolic levels, we have reviewed all of its known phytochemicals and enquired about their regulatory potential against various protein targets by developing high-confidence tripartite networks consisting of phytochemical—protein target—disease association. We have also (i) studied immunomodulatory potency of this herb; (ii) developed subnetwork of human PPI regulated by its phytochemicals and could successfully associate its specific modules playing important role in diseases, and (iii) reported several novel drug targets. P10636 (microtubule-associated protein tau, that is involved in diseases like dementia etc.) was found to be the commonly screened target by about seventy percent of these phytochemicals. We report 20 drug-like phytochemicals in this herb, out of which 7 are found to be the potential regulators of 5 FDA approved drug targets. Multi-targeting capacity of 3 phytochemicals involved in neuroactive ligand receptor interaction pathway was further explored via molecular docking experiments. To investigate the molecular mechanism of P. longum’s action against neurological disorders, we have developed a computational framework that can be easily extended to explore its healing potential against other diseases and can also be applied to scrutinize other indigenous herbs for drug-design studies.

Piper nigrum and piperine: an update

Black pepper (Piper nigrum L.) is a very widely used spice, known for its pungent constituent piperine. However, in addition to its culinary uses, pepper has important medicinal and preservative properties, and, more recently, piperine has been shown to have fundamental effects on p-glycoprotein and many enzyme systems, leading to biotransformative effects including chemoprevention, detoxification, and enhancement of the absorption and bioavailability of herbal and conventional drugs. Based on modern cell, animal, and human studies, piperine has been found to have immunomodulatory, anti-oxidant, anti-asthmatic, anti-carcinogenic, anti-inflammatory, anti-ulcer, and anti-amoebic properties. In this review, the chemical constituents, biological activities, effects of processing, and future potential of black pepper and piperine have been discussed thoroughly.

Comparative therapeutic effect of probiotic Lactobacillus casei alone and in conjunction with antiprotozoal drugs in murine giardiasis

Various antiprotozoal drugs have been used to counteract the spread of giardiasis. However, due to increase in resistance to these compounds, there is an urgent need to find a natural biocompatible product to fight the pathogen in more healthy and effective way. The present study was designed to compare the therapeutic effect of probiotic Lactobacillus casei alone and in conjunction with antiprotozoal drugs on the outcome of giardiasis in murine model. BALB/c mice were challenged with Giardia intestinalis trophozoites, and 1 day after infection, these mice were treated with either probiotic alone or in conjunction with antiprotozoal drugs. Cyst, trophozoite, and lactobacilli counts were monitored vis-a-vis histopathological alterations in the small intestine. It was found that albendazole administered orally 1 day after Giardia infection was the most effective antiprotozoal drug among albendazole, tinidazole, metronidazole, and nitazoxanide. It reduced both the severity and duration of giardiasis. More specifically, oral administration of the probiotic L. casei in conjunction with albendazole further reduced the Giardia infection as was evident by the restored normal gut morphology. This suggests that probiotics and antiprotozoal drugs in combination may be the better alternative therapy for treatment of gastrointestinal diseases and enhanced recovery.

Overview for various aspects of the health benefits of Piper longum linn. fruit

Herbal remedies have become popular, due in part to the lower risk of adverse reactions. Thousands of plants have been used traditionally to treat various diseases. Among them, species of the genus Piper are important medicinal plants used in various systems of medicine. The Piper longum fruit has been used in traditional medicine, including the Ayurvedic system of medicine. Although there are numerous indications for its use, controlled trials are needed to determine its efficacy. The primary constituents isolated from various parts of P. longum are piperine, piperlongumine, sylvatin, sesamin, diaeudesmin piperlonguminine, pipermonaline, and piperundecalidine. It is most commonly used to treat chronic bronchitis, asthma, constipation, gonorrhea, paralysis of the tongue, diarrhea, cholera, chronic malaria, viral hepatitis, respiratory infections, stomachache, bronchitis, diseases of the spleen, cough, and tumors. This study provides detailed information about the P. longum fruit, including phytochemistry, pharmacological profile and safety profile. In view of the commercial, economic, and medicinal importance of the P. longum plant, it is useful for researchers to study the plant in detail.

The prevalence of giardia intestinalis in dyspeptic and diabetic patients

Background and Aims. We aimed to investigate the prevalence of Giardiasis in patients with dyspepsia and patients with diabetes mellitus. Methods. 400 patients and 100 healthy persons were included in this clinical prospective study. The number of patients in each group was equal, 200 dyspeptic and 200 diabetic, respectively. The antigen of G. lntestinalis was determined in the stool specimens by ELISA method. Results. The frequency of Giardiasis was 7% in dyspeptic and 15% in diabetic patients. There was no positive results in any of the healthy persons. There was a significant difference in prevalence rate of Giardiasis between patients with dyspepsia and diabetes mellitus (P < 0.05). Conclusions. These results revealed that the prevalence of Giardiasis in dyspepsia and with diabetes mellitus was high in our country. This is the first study investigating the prevalence of Giardiasis in diabetic patients. To investigate Giardiasis in diabetic patients, who have dyspepsia or not, may be a good approach for public health.

Effects of Essential Oils on the Growth of Giardia lamblia Trophozoites

Giardia lamblia is one of the most important worldwide causes of intestinal infections produced by protozoa. Current therapy for giardiasis is unsatisfactory due to high incidence of undesirable side effects and significant failure in clearing parasites from the gastrointestinal tract. In the search for new therapeutic agents, we report on the effect of several essential oils on G. lamblia growth. Among eighteen tested essential oils, those with phenolic compositions were the most active, particularly if containing high contents of carvacrol, such as Thymbra capitata and Origanum virens (IC50 values of 71 and 85 μg.mL−1, respectively). The oils from Syzygium aromaticum and Thymus zygis subsp. sylvestris (IC50 values from 100 to 200 μg.mL−1), as well as, those from Mentha x piperita and Lippia graveolens (IC50 values over 200 μg.mL−1) were less active. Results support the concept that several essential oils or some of their constituents may be useful in the clinical management of Giardia infections.

Antiplatelet activities of newly synthesized derivatives of piperlongumine

Piperlongumine, a pyridone alkaloid isolated from Piper longum L., exhibited a potential inhibitory effect on washed rabbit platelet aggregation induced by collagen, arachidonic acid (AA) and platelet activating factor (PAF), without any inhibitory effect on that induced by thrombin. Piperlongumine was used as a lead compound for the synthesis of new antiplatelet agents. Seven synthetic compounds were newly synthesized from 3,4,5-trimethoxycinnamic acid (TMCA). They were 1-piperidin-1-yl-3-(3,4,5-trimethoxy-phenyl)prop-2-en-1-one (1'), 1-morpholin-4-yl-3-(3,4,5-trimethoxyphenyl)prop-2-en-1-one (2'), 1-(3,5-dimethylpiperidin-1-yl)-3-(3,4,5-trimethoxyphenyl)prop-2-en-1-one (3'), 1-(2-methylpiperidin-1-yl)-3-(3,4,5-tri-methoxyphenyl)prop-2-en-1-one (4'), 1-(3-hydroxypiperidin-1-yl)-3-(3,4,5-trimethoxyphenyl)- prop-2-en-1-one (5'), 1-[3-(3,4,5-tri-methoxyphenyl) acryloyl]-piperidin-2-one (6') and ethyl 1-[3-(3,4,5-trimethoxyphenyl)-acryloyl]piperidine-4-carboxylate (7'). Among those seven synthetic derivatives, 1-(3,5-dimethylpiperidin-1-yl)-3-(3,4,5-trimethoxyphenyl)prop-2-en-1-one (3') had the most inhibitory effect on platelet aggregation induced by collagen, AA and PAF.

Methylpiperate derivatives from Piper longum and their inhibition of monoamine oxidase

We have previously reported that piperine, a known piperidine alkaloid from Piper longum, competitively inhibited mouse brain MAO-A and MAO-B activities. Piperine also showed in vivo antidepressant-like activity against the tail suspension test. In the present study, we further expanded on the identification of MAO inhibitors from the fruit of P. longum. Activity-guided fractionation of a methylene chloride soluble extract led to the isolation of three known piperine-related compounds, methylpiperate (1), guineensine (2), and piperlonguminine (3). Of these, methylpiperate (1) and guineensine (2) showed significant MAO inhibitory activities with IC50 values of 3.6 and 139.2 microM, respectively. Furthermore, methylpiperate (1) exhibited a selective inhibitory effect against MAO-B (IC50 value: 1.6 microM) than MAO-A (IC50 value: 27.1 microM). The kinetic study using the Lineweaver-Burk plots analysis suggested that methylpiperate (1) competitively inhibits MAO-A and MAO-B activities with the Ki values of 23.5 and 1.3 microM, respectively.

Antiplatelet effects of acidamides isolated from the fruits of Piper longum L

The inhibitory effects of four acidamides, piperine, pipernonaline, piperoctadecalidine, and piperlongumine, isolated from the fruits of Piper longum L. on washed rabbit platelet aggregation were examined. All of the four tested acidamides showed dose-dependent inhibitory activities on washed rabbit platelet aggregation induced by collagen, arachidonic acid (AA), and platelet-activating factor (PAF), except for that induced by thrombin. Piperlongumine, in particular, showed stronger inhibitory effects than other acidamides to rabbit platelet aggregation induced by collagen, AA and PAF.

The anti-amoebic activity of some medicinal plants used by AIDS patients in southern Thailand

The anti-amoebic activities of chloroform, methanol and water extracts from 12 Thai medicinal plants (39 extracts) commonly used by AIDS patients in southern Thailand were screened, at a concentration of 1,000 microg/ml, against Entamoeba histolytica strain HTH-56:MUTM and strain HM1:IMSS growing in vitro. The extracts were incubated with 2x10(5) E. histolytica trophozoites/ml of medium at 37 degrees C under anaerobic conditions for 24 h. The cultures were examined with an inverted microscope and scored (1-4) according to the appearance and numbers of the trophozoites. The extracts that caused inhibition were selected and retested using the same conditions but with concentrations that ranged from 31.25 to 1,000 microg/ml using E. histolytica strain HM1:IMSS, and the IC(50) values for each extract were calculated. The chloroform extracts from Alpinia galanga (IC(50) 55.2 microg/ml), Barleria lupulina (IC(50) 78.5 microg/ml), Boesenbergia pandurata (IC(50) 45.8 microg/ml), Piper betle (IC(50) 91.1 microg/ml) and Piper chaba (IC(50) 71.4 microg/ml) and the methanol extract from B. pandurata (IC(50) 57.6 microg/ml) were all classified as "active", i.e. with an IC(50) of less than 100 microg/ml, whereas those from Murraya paniculata (IC(50) 116.5 microg/ml) and Zingiber zerumbet (IC(50) 196.9 microg/ml) were classified as being "moderately active". The IC(50) of a standard drug, metronidazole, was 1.1 microg/ml.

Giardiasis in patients with dyspeptic symptoms

AIM: To investigate the prevalence of giardiasis in patients with dyspeptic symptoms.

METHODS: Clinical records of consecutive patients who attended Gastroenterology Department at Aga Khan University Hospital from January 2000 to June 2003 and had esophagogastroduodenoscopy (EGD) with duodenal biopsies and international classification of diseases 9^th revision with clinical modifications (ICD-9-CM) coded with giardiasis were studied.

RESULTS: Two hundred and twenty patients fulfilled the above criteria. There were 44% (96/220) patients who were giardiasis positive, 72% (69/96) of them were males and 28% (27/96) of them were females. There were 65% (81/124) males and 35% (43/124) females who were giardiasis negative. The mean age of patients with giardiasis was 28±17 years, while that of giardiasis negative patients was 40±18 years (P<0.001). In patients with giardiasis, abdominal pain was present in 71% (68/96) of patients (P = 0.02) and diarrhea in 29% (28/96) (P = 0.005); duodenitis in 25% (24/96) on EGD (P = 0.006) and in 68% (65/96) on histopathology (P = 0.002).

CONCLUSION: Giardiasis occurs significantly in young people with abdominal pain, while endoscopic duodenitis is seen in only 25% of giardiasis positive cases, which supports routine duodenal biopsy.

The effects of extracts from anti-diarrheic Thai medicinal plants on the in vitro growth of the intestinal protozoa parasite: Blastocystis hominis

The activities of n-hexane, dichloromethane and methanol extracts from five anti-diarrheic Thai medicinal plants, Acacia catechu (Fabaceae) resin, Amaranthus spinosus (Amaranthaceae) whole plant, Brucea javanica (Simaroubaceae) seed, Piper longum (Piperaceae) fruit and Quercus infectoria (Fagaceae) nut gall were tested against the in vitro growth of fresh isolates of the intestinal protozoan parasite, Blastocystis hominis. The extracts at concentrations that ranged from 62.5 to 2000 microg/mL, were incubated with several isolates of Blastocystis hominis for 48 h. The activities were classified as killed, inhibited, moderately inhibited and not-inhibited. Dichloromethane and methanol extracts from the Brucea javanica seed and a methanol extract from Quercus infectoria nut gall showed the highest activity. At a concentration of 2000 microg/mL, the three extracts killed 82, 75 and 67% of the Blastocystis hominis samples tested and inhibited 94, 100 and 76% of them, respectively. Metronidazole, used as a reference antiprotozoan drug, at a concentration of 40 microg/mL, killed 97% of the Blastocystis hominis isolates and inhibited all samples tested at concentrations that ranged from 1.25 to 20 microg/mL.

The in vitro anti-giardial activity of extracts from plants that are used for self-medication by AIDS patients in southern Thailand

This study evaluated the anti-giardial activity of chloroform, methanol and water extracts of 12 medicinal plants (39 extracts), commonly used as self medication by AIDS patients in southern Thailand. The plant extracts and a standard drug, metronidazole, were incubated with 2x10(5) trophozoites of Giardia intestinalis per millilitre of growth medium in 96-well tissue culture plates under anaerobic conditions for 24 h. The cultures were examined with an inverted microscope and the minimum inhibitory concentration and the IC50 value for each extract was determined. The chloroform extracts from Alpinia galanga, Boesenbergia pandurata, Eclipta prostrata, Piper betle, Piper chaba, Zingiber zerumbet, and the methanol extracts from B. pandurata and E. prostrata were classified as "active", i.e. with an IC50 of <100 microg/ml, whereas the chloroform extract from Murraya paniculata was classified as being "moderately active". This study shows that extracts from some medicinal plants have potential for use as therapeutic agents against G. intestinalis infections.

Efficacy of antigiardial drugs

The flagellated protozoa Giardia duodenalis is the most commonly detected parasite in the intestinal tract of humans. Infections with the parasite result in diarrhoeal disease in humans and animals, with infants at risk from failure-to-thrive syndrome. The incidence of giardiasis worldwide may be as high as 1000 million cases. Current recommended treatments include the nitroheterocyclic drugs tinidazole, metronidazole and furazolidone, the substituted acridine, quinacrine, and the benzimidazole, albendazole. Paromomycin is also used in some situations, and nitazoxanide is proving to be useful. However, treatment failures have been reported with all of the common antigiardial agents, and drug resistance to all available drugs has been demonstrated in the laboratory. In addition, clinical resistance has been reported, including cases where patients failed both metronidazole and albendazole treatments. The identification of new antigiardial drugs is an important consideration for the future, but maintaining the usefulness of the existing drugs is the most cost-effective measure to ensure the continued availability of antigiardial drugs.

Treatment of giardiasis

Giardia lamblia is both the most common intestinal parasite in the United States and a frequent cause of diarrheal illness throughout the world. In spite of its recognition as an important human pathogen, there have been relatively few agents used in therapy. This paper discusses each class of drugs used in treatment, along with their mechanism of action, in vitro and clinical efficacy, and side effects and contraindications. Recommendations are made for the preferred treatment in different clinical situations. The greatest clinical experience is with the nitroimidazole drugs, i.e., metronidazole, tinidazole, and ornidazole, which are highly effective. A 5- to 7-day course of metronidazole can be expected to cure over 90% of individuals, and a single dose of tinidazole or ornidazole will cure a similar number. Quinacrine, which is no longer produced in the United States, has excellent efficacy but may be poorly tolerated, especially in children. Furazolidone is an effective alternative but must be administered four times a day for 7 to 10 days. Paromomycin may be used during early pregnancy, because it is not systematically absorbed, but it is not always effective. Patients who have resistant infection can usually be cured by a prolonged course of treatment with a combination of a nitroimidazole with quinacrine.