Xanthine oxidase inhibitory properties of Czech medicinal plants

Aim of the study

To investigate in vitro xanthine oxidase inhibitory properties of plants traditionally used in Czech Republic and Central-East Europe region for gout, arthritis or rheumatism treatment.

Materials and methods

Methylene chloride-methanolic and two ethanolic extracts of 27 plant species were screened for in vitro xanthine oxidase inhibitory activity using a spectrophotometric method.

Results

Around 50% of the species exhibited some degree of xanthine oxidase inhibitory properties at 200 μg/mL, showing a moderate correlation (r = 0.59) with total phenol content. The most active were methylene chloride-methanolic extracts of Populus nigra and Betula pendula, with IC₅₀ of 8.3 and 25.9 μg/mL, respectively, followed by 80% ethanolic extract of Caryophyllus aromaticus and Hypericum perforatum, both under 50 μg/mL.

Conclusions

Populus nigra and Betula pendula were identified as species with the highest xanthine oxidase inhibitory potential in our study. This correlates with the ethnobotanical data on their use in Central European folklore and provides the basis for further investigation on these plants.     

Xanthine oxidase inhibitory activity of selected Australian native plants

Twenty-eight extracts from 17 species of Australian native plants traditionally used as general anti-inflammatory medicines by Australian Aboriginal people were examined for inhibition of the enzyme xanthine oxidase (XO). The extracts from nine species were found to have more than 25% inhibition at a concentration of 100 microg/ml in the assay mixture. Extracts from three species Clerodendrum floribundum R. Br. (Verbenaceae), Eremophila maculata (Ker Gawler) (Myoporaceae) and Stemodia grossa Benth. (Scrophulariaceae) showed the greatest activity with inhibitions of 84, 61 and 57%, respectively, at 50 microg/ml, with four other species having more than 40% inhibitory activity at this concentration.     

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

Aim of the study

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

Materials and methods

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

Results

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

Conclusion

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

Xanthine oxidase inhibitory activity of Chilean Myrtaceae

Twenty-one Myrtaceae collections belonging to 10 species, 5 of which are used in Chilean folk medicine, were assayed for inhibitory activity towards the enzyme xanthine oxidase. Most leaf and stem extracts were devoid of activity or showed a weak inhibitory effect. Chilean ethnobotanical data on the species are linked to the astringent properties of Myrtaceae and their use for treating wounds and diarrhea. The results show the advantage of using proper plant selection criteria when searching for new drugs to treat human gout.     

Xanthine oxidase inhibitory activity of Paraguayan Myrtaceae

Nineteen Myrtaceae collections belonging to 15 species, 12 of which are used in Paraguayan folk medicine, were assayed for inhibitory activity towards the enzyme xanthine oxidase. Most leaf and stem extracts were active showing IC50 values ranging from 3.0 to 50 micrograms/ml. The reported activities support existing ethnobotanical data concerning their use for the treatment of gout.     

Screening of some Palestinian medicinal plants for antibacterial activity

Antibacterial activity of organic and aqueous extracts of 15 Palestinian medicinal plants were carried against eight different species of bacteria: Bacillus subtilis, two Escherichia coli species, Staphylococcus aureus (methicillin resistant), two S. aureus (methicillin sensitive) species, Pseudomonas aeruginosa, and Enterococcus fecalis. Of the 15 plants tested, eight showed antibacterial activity. Each plant species has unique against different bacteria. The most active antibacterial plants against both gram-positive and gram-negative bacteria were Thymus vulgaris and Thymus origanium. The organic and aqueous extract from the same plants showed different activities; the organic extract showed the same or greater activity than the aqueous extract. Finally, the hole–plate diffusion method showed larger activity than the disc diffusion method.     

Screening of Indian medicinal plants for acetylcholinesterase inhibitory activity

The cholinergic hypothesis of Alzheimer's disease (AD) has provided the rationale for the current pharmaco-therapy of this disease, in an attempt to reduce the cognitive decline caused by cholinergic deficits. Nevertheless, the search for potent and long-acting acetylcholinesterase (AChE) inhibitors that exert minimal side effects in AD patients is still ongoing. AChE inhibitors are currently the only approved therapy for the treatment of Alzheimer's disease; only a limited number of drugs are commercially available. Hydroalcohol extracts of six herbs, Andrographis paniculata, Centella asiatica, Evalvulus alsinoides, Nardostachys jatamansi, Nelumbo nucifera, Myristica fragrans used in Indian systems of medicine, were tested for in vitro acetylcholinesterase inhibitory activity based on Ellman's method in 96-well microplates using AChE obtained from bovine erythrocytes. The results showed that the hydroalcohol extract from Centella asiatica, Nardostachys jatamansi, Myristica fragrans, Evalvulus alsinoides inhibited 50% of AChE activity at concentrations of 100-150 microg/mL. Andrographis paniculata and Nelumbo nucifera extracts showed a weak inhibition of acetylcholinesterase with IC(50) values of 222.41 +/- 19.87 microg/mL and 185.55 +/- 21.24 microg/mL, respectively. Physostigmine was used as a standard and showed inhibition of acetylcholinesterase with an IC(50) value of 0.076 +/- 0.0042 microg/mL.     

柑橘属药材乙酸乙酯提取物抑制黄嘌呤氧化酶作用的谱效关系研究

目的 阐明不同柑橘属药材乙酸乙酯提取物指纹图谱特征峰对黄嘌呤氧化酶抑制作用的贡献程度.方法 建立枳实、青皮、陈皮、橘红和香橼乙酸乙酯提取物指纹图谱,HPLC法测定黄嘌呤氧化酶-黄嘌呤反应体系尿酸生成量,评价各提取物对黄嘌呤氧化酶活性的影响,采用灰关联度分析法研究谱效关系,对照品比对法鉴定主要色谱峰.结果 谱效关系分析表明,各药材提取物的黄嘌呤氧化酶抑制活性是多成分共同作用的结果,各色谱峰所代表的化学成分对抑制黄嘌呤氧化酶活性的贡献大小顺序为圣草次苷＞柚皮苷＞柚皮素＞橙皮苷＞桔皮素＞川陈皮素＞新橙皮苷＞橙皮素.结论 不同柑橘属药材乙酸乙酯提取物指纹图谱特征峰与黄嘌呤氧化酶抑制作用有一定的对应关系.     

Antituberculosis potential of some ethnobotanically selected Malaysian plants

Aim of the study

Many local plants are used in Malaysian traditional medicine to treat respiratory diseases including symptoms of tuberculosis. The aim of the study was to screen 78 plant extracts from 70 Malaysian plant species used in traditional medicine to treat respiratory diseases including symptoms of tuberculosis for activity against Mycobacterium tuberculosis H37Rv using a colorimetric microplate-based assay.

Materials and methods

Plant extracts were prepared by maceration in methanol (80%) and antituberculosis screening was carried out using Tetrazolium bromide microplate assay (TEMA) method to determine the minimum inhibitory concentration (MIC).

Results

Thirty-eight plant extracts from 36 plant species exhibited antituberculosis activity with MICs in the range of 1600-400 μg/ml. The leaf extract of Angiopteris evecta exhibited the highest activity with MIC of 400 μg/ml. Five other extracts, namely, Costus speciosus (stem and flower), Piper sarmentosum (whole plant), Pluchea indica (leaf), Pluchea indica (flower), and Tabernaemontana coronaria (leaf) exhibited antituberculosis activity, each with MIC of 800 μg/ml. To the best of our knowledge, this is the first report of in vitro high throughput screening of Malaysian medicinal plants for antituberculosis activity.

Conclusions

Antituberculosis activity of extracts of some plants justifies, to a certain extent their ethnomedicinal uses as remedies for symptoms of tuberculosis. These results also support the general view that, selecting the plants based on ethnobotanical criteria would enhance the probability of finding species with antituberculosis activity.     

芹菜素对黄嘌呤氧化酶电极的抑制作用研究

目的：研究在XOD／SWNTs—DDAB修饰电极上芹菜素黄嘌呤氧化酶的抑制作用。方法：将黄嘌呤氧化酶固体与SWNTs—DDAB修饰电极上,并且保持酶的生物活性,采用循环伏安法研究芹菜素对黄嘌呤氧化酶电极的押制作用。结果：SWNTs-DDAB修饰膜能够保持酶的生物活性并对黄嘌呤的催化活性;此修饰电极对黄嘌呤比较敏感;芹菜素能够明显的抑制嘌呤氧化酶。结论：SWNTs-DDABmo膜是较好的固定酶修饰膜,运用电化学方法筛选酶的抑制剂是可行的,确定了芹菜素对酶的抑制作用。     

Screening of some medicinal plants from cameroon for beta-lactamase inhibitory activity

In efforts to find new bioactive beta-lactamase inhibitors, this study investigated 16 Cameroonian plants belonging to 10 families which were evaluated for anti-beta-lactamase activity. The investigation showed that extracts 2, 6, 3 and 5 of the 16 plants investigated presented interesting in vitro beta-lactamase inhibition (over 90%), respectively, of the beta-lactamases TEM-1, OXA-10, IMP-1 and P99. These extracts were from Mammea africana (all beta-lactamases), Garcinia lucida, G. kola (OXA-10, IMP-1 and P99), Bridelia micrantha (OXA-10, P99), Ochna afzelii (OXA-10, P99), Prunus africana (IMP-1) and Adenia lobata (TEM-1). After elimination of tannins (according to the European Pharmacopoeia) the extracts from B. micrantha, G. lucida and M. africana were tested further for their anti-beta-lactamase activity. The extracts from B. micrantha and G. lucida exhibited potent inhibitory activity, respectively, of beta-lactamase OXA-10 (IC(50) = 0.02 mg/mL) and P99 (IC(50) = 0.01 mg/mL). The anti-beta-lactamase activity of M. africana extract was weak. The isolation and the structural elucidation of the active constituents of G. lucida and B. micrantha will provide useful leads in the development of beta-lactamase inhibitors.     

Xanthine oxidase inhibitory activity of Lychnophora species from Brazil ("Arnica")

Twenty-two extracts from five Lychnophora species and one Lychnophoriopsis species, traditionally used in Brazil as analgesic, anti-inflammatory, and to treat bruise and rheumatism were examined for the inhibition of xanthine oxidase (XO), the enzyme that catalyses the metabolism of hypoxanthine and xanthine into uric acid. Sixteen extracts were tested. All of them were found to have excellent XO inhibitory activity, with inhibitions greater than 38% at 100 microg/mL in the assay mixture. The most active plants examined were Lychnophora trichocarpha, Lychnophora ericoides, Lychnophora staavioides and Lychnophoriopsis candelabrum, with inhibitions of 77%, 78%, 66% and 63% at 100 microg/mL, respectively, and IC(50) values of 6.16, 8.28, 33.97 and 37.70 microg/mL, respectively.     

Antimicrobial activity of medicinal plants against oral microorganisms

Ethanol extracts of eight plant species used traditionally in South Africa for the treatment of oral diseases were investigated for in vitro antimicrobial activity against oral pathogens namely Actinobacillus actinomycetemcomitans, Actinomyces naeslundii, Actinomyces israelii, Candida albicans, Porphyromonus gingivalis, Privotella intermedia and Streptococcus mutans using the disk diffusion method. Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of ethanol extracts were determined against these microorganisms using micro dilution. The cytotoxicity and therapeutic index (TI) of selected active extracts were also determined. Out of eight plants, six (Annona senegalensis, Englerophytum magalismontanum, Dicerocarym senecioides, Euclea divinorum, Euclea natalensis, Solanum panduriforme and Parinari curatellifolia) exhibited MIC values ranging from 25.0 mg/ml to 0.8 mg/ml. Gram negative bacteria were found to be more resistant to the plant extracts than Gram positive bacteria, except for Euclea natalensis which inhibited all three Gram negative bacteria tested in this study. All plant extracts showed moderate cytotoxicity on the Vero cell line. The fifty percent inhibitory concentration (IC₅₀) of all plants tested range from 92.3 to 285.1 μg/ml.     

Screening of Brazilian medicinal plants for antiviral activity against rotavirus

Ethnopharmacological relevance

Brazilian medicinal plants traditionally used for the treatment of diarrhoea were investigated for their in vitro antiviral activity against the simian rotavirus SA11.

Materials and methods

The ethanolic crude extracts of plants collected in the cerrado of Minas Gerais, Brazil were submitted to phytochemical screening. The cytotoxicity of the extracts was inferred by cellular morphologic alterations. Antiviral activity was assessed by the ability of the extracts to inhibit the cytopathic effect (CPE) of rotavirus on the treated cells. RT-PCR was performed to confirm and/or confront antiviral assay data.

Results

The maximum non-toxic concentration ranged from 50 to 500 μg/mL. All extracts were toxic at a concentration of 5000 μg/mL but no extract showed cytotoxicity at 50 μg/mL. The species Byrsonima verbascifolia, Myracrodruon urundeuva, Eugenia dysenterica and Hymenaea courbaril exhibited the strongest in vitro activity against rotavirus. Their extracts prevented the formation of CPE, and RT-PCR analysis detected no amplification of genetic material from rotavirus. Tannins, flavonoids, saponins, coumarins and terpenes were the major classes of natural products found in the leaf extracts that showed antiviral activity.

Conclusion

Among the species studied, Byrsonima verbascifolia, Eugenia dysenterica, Hymenaea courbaril and Myracrodruon urundeuva showed potential activity against rotavirus and are worthy of further study. The present study corroborates ethnopharmacological data as a valuable source in the selection of plants with antiviral activity and to some extent validates their traditional uses.     

Antibacterial activity of some Moroccan medicinal plants

The extracts of 12 plants selected on the basis of the folk-medicine reports were examined for their antibacterial effects against eight pathogenic bacteria. The n-butanol extract of Calotropis procera flowers and the aqueous extract of Eugenia caryophyllata proved to be the most effective against the bacteria tested.     

Analgesic activity of some Indian medicinal plants

In the present study of some of the Indian medicinal plants Sida acuta whole plant (Malvaeae), Stylosanthes fruticosa (whole plant) (Papilionaceae), Toona ciliata (heart wood) (Meliaceao), Bougainvilla spectabilis (leaves) (Nyctaginaceae), Ficus glomerata (bark, leaves) (Moraceae) and Polyalthia longifolia (leaves) (Annonaceae). The different plants were used in folklore medicine in the treatment of toothache and strengthening of gums, anthelmintic, kidney diseases, analgesic, anti-inflammatory, hepatoprotective, antihyperglycaemic, antihyperglycaemic and anticancer. The extract was prepared using powdered material with ethanol, concentrated under vacuo and were evaluated for analgesic activity by analgesiometer at three dose level (100, 300 and 500mg/kg). Analgesic activity was significant with Toona ciliata (heart wood) ethanolic extract when compared with other extracts and its activity was confirmed by tail immersion method.     

Tetrahydroamentoflavone (THA) from Semecarpus anacardium as a potent inhibitor of xanthine oxidase

Ethnopharmacological relevance

Seed of Semecarpus anacardium L. is widely used in Indian traditional medicine; Ayurveda and Sidha, for treatment of inflammatory disorders and gout.

Aim of the study

The present study was aimed at isolation of a compound for its potential to inhibit xanthine oxidase (XO), over expression of which lead to inflammation and gout.

Materials and methods

Activity guided fractionation of S. anacardium seed was conducted using liquid-liquid partition and preparative HPLC. The fractions were evaluated for their XO inhibition and antioxidant activity. The ethyl acetate fraction with the highest XO activity yielded a biflavonoid compound tetrahydroamentoflavone (THA). Lineweaver-Burk (LB) plot for the XO inhibition of THA and allopurinol was constructed from the kinetic data.

Results

IC₅₀ values of THA and allopurinol for XO inhibition were 92 and 100 nM respectively and their corresponding values for K_i were 0.982 and 0.612 μM respectively.

Conclusion

THA was a potent XO inhibitor which could be considered as a drug candidate or chemopreventive agent, after establishing its pharmacological and clinical evaluation. The study results appear to support the claim of the traditional medicine with respect to the efficacy of S. anacardium seed against inflammation and gout.     

Abortifacient activity of some Nigerian medicinal plants

The abortifacient effects of five plant species commonly used by Nigerian traditional birth attendants to achieve relatively painless delivery, hasten fetal delivery and evacuate retained placenta were investigated. Aqueous extracts of the plants were prepared and screened pharmacologically using isolated smooth muscle preparations and pregnant animals. The extracts were also subjected to toxicological and phytochemical studies. The extracts contracted isolated uterine smooth muscle preparation and potentiated oxytocin-induced responses of the uterus. In the whole animal, the extracts caused expulsion of fetuses in the third trimesters of pregnancy. These results appear to justify their traditional uses.     

Anti-plasmodial activity of the extracts of some Kenyan medicinal plants

Ethnopharmacological relevance

The spread of drug resistant Plasmodium falciparum strains necessitates search for alternative newer drugs for use against malaria. Medicinal plants used traditionally in preparation of herbal medicines for malaria are potential source of new anti-malarial drugs.

Aim of the Study

To identify the anti-plasmodial potential of twelve plants used in preparing herbal remedies for malaria in Kilifi and Tharaka districts of Kenya.

Materials and Methods

Twelve plants used traditionally for anti-malarial therapy in Kilifi and Tharaka districts were extracted with water/methanol yielding twenty-three extracts. The extracts were tested against chloroquine sensitive (NF54) and resistant (ENT30) P. falciparum strains in vitro using ³Hypoxanthine assay.

Results

Seven (30%) extracts showed activity against P. falciparum with IC₅₀ values below 20 μg/ml. The remaining 16 extracts showed low or no activity. The most active extracts were from Zanthoxylum chalybeum (Rutaceae) with an IC₅₀ value of 3.65 μg/ml, Cyperus articulatus (Cyperaceae) with 4.84 μg/ml, and Cissampelos pareira (Menispermaceae) with 5.85 μg/ml.

Conclusions

This study revealed plants, that are potential sources of anti-malarial compounds. Anti-plasmodial activities of extracts of T. simplicifolia, C. pareira, and C. articulatus are reported for the first time.     

Xanthine oxidase inhibitory activity of northeastern North American plant remedies used for gout

Xanthine oxidase (xanthine: oxygen oxidoreductase EC 1.2.3.2) inhibitory activity was assayed from 26 species belonging to 18 families traditionally used for the treatment of gout and related symptoms by Indigenous people of northeastern North America. The degree of inhibition was determined by measuring the increase in absorbance at 295 nm associated with uric acid formation. Eighty-eight percent of the plants were found to have inhibitory activity at 100 microg/ml, with 20% having greater than 50% inhibition. Larix laricina exhibited the highest activity with an inhibition of 86.33%. Of the species with the highest activity, Lineweaver-Burk plots showed that inhibition mode was of linear mixed-type. Inhibitory activity of the plants correlated positively with their phenolic content (r = 0.52 P < 0.01) and tannin content (r = 0.59 P < 0.001).