Medicinal plants with hypoglycemic activity

This review summarises the literature on the antidiabetic activity of 343 medicinal plants reputed in the indigenous system of medicine or in which the pharmacological activity has been scientifically demonstrated. The data are presented in tabular form. The table reflects the plant parts involved, the nature of the extracts used and the names of the active principles with their structures where known. The pharmacological activities of some of the extracts or of the active principles isolated from these plants are also described.     

Medicinal plants and industry

Beyond their direct use in traditional medicine, medicinal plants are used on an industrial scale to produce total extracts and tinctures, purified extracts and chemical products.The importance of the appropriate solvents to prepare extracts and their correct use in pharmaceutical formulations are emphasized.Generally, purified extracts, because they contain a total mixture of the active principles, are more active than the single components of the mixture.The cultivation of medicinal plants in their original habitat represents the most suitable means to comply with the increasing demand for medicinal plants and to avoid the depletion of natural sources.     

Screening of some Siberian medicinal plants for antimicrobial activity

The antimicrobial activity of crude ethanolic extracts of 16 Siberian medicinal plants was tested against five species of microorganisms: Bacillus cereus, Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, and Candida albicans. Of the 16 plants tested, 12 showed antimicrobial activity against one or more species of microorganisms. The most active antimicrobial plants were Bergenia crassifolia, Chelidonium majus, Rhaponticum carthamoides, Sanguisorba officinalis, and Tussilago farfara.     

Screening of some Cuban medicinal plants for antimicrobial activity

The antimicrobial activities of 23 extracts of 12 Cuban plant species reported in traditional medicine were tested. The agar diffusion method was used to assess the activity against four bacteria and one yeast: Staphylococcus aureus, Bacillus subtilis, Escherichia coli, Pseudomonas aeruginosa and Candida albicans. The results, evaluated as the diameter of the inhibition zone of microbial growth, showed that nine extracts were active against Gram-positive bacteria but only two of these proved to be also active against Gram-negative bacteria. None of the extracts inhibited the growth of the yeast. The most susceptible bacterium was Staphylococcus aureus and the best antibacterial activity was shown by Schinus terebenthifolius.     

Medicinal plants in Colombia

The botanical aspects of the plants of Colombia have been studied thoroughly since the 18th century. Nevertheless, although plants are used to a large extent in traditional medicine in Colombia, there has been little investigation into their properties. Some research has now been initiated. This work is supported by the existence of the National Herbarium in Bogota, in which there are 180 000 specimens belonging to 10 000 different species.     

Screening of some indigenous Qatari medicinal plants for antimicrobial activity

Aqueous, ethanol and butanol crude extracts of the aerial parts of ten plants exhibited variable degrees of antimicrobial activity against four bacterial and two fungal species. Aqueous extracts had low antimicrobial activity against E.coli, P.aeruginosa, B. cerreus, S.aureus, C.albicans and A.flavus. Avicennia marina (AM) aqueous extract exhibited a moderate antifungal activity. Ethanol and butanol crude extracts exhibited an improved antimicrobial activity. However, butanol exhibited a superior antimicrobial activity compared with aqueous and ethanol crudes. Compared with the standard antibiotics tested the butanol extract had the highest activity. Butanol extracts at 2000 microg/disc of AM, Lotus halophilus (LA), Pulicaria gnaphaloides (PG) and Capparis spinosa (CS) had a very good antibacterial activity against both gram-positive and -negative bacteria as well as moderate to good antifungal activity against C. albicans and A. flavus. Medicago laciniata (ML), Limonium axillare (LA) and (PG) butanol crude extract compared with standard chloramphenicol, tetracycline and nalidixic acid exhibited a superior antifungal activity.     

Screening of selected indigenous plants of Lebanon for antimicrobial activity

The objective of this study is to test in vitro the antimicrobial efficacy of 39 water and 39 methanol extracts derived from different parts of 27 indigenous wild plant species that have been commonly used in Lebanese folk medicine. The antimicrobial efficacy was determined using the single disk diffusion method, with 10 and 20 microl load extract volume per disc. Nine test microorganisms were used namely, Escherichia coli, Proteus sp., Pseudomonas aeruginosa, Shigella dysenteria, Salmonella enteritidis, Salmonella typhi, Staphylococcus aureus, Streptococcus faecalis, and Candida albicans. Only one water extract out of 39 derived from whole plant of Alchemilla diademata showed an antimicrobial activity against Staphylococcus aureus. The percentage of test organisms that were susceptible to 10 most efficacious methanol plant extracts (20 microl/disc) were as follows: Achillea damascena whole plant (88.8%), Anthemis scariosa flower (88.8%), Cirsium sp. whole plant (88.8%), Centaurea ainetensis flowers (88.8%), Hieracium sp. whole plant (88.8%), Origanum libanoticum whole plant (99.9%), Ranunculus myosuroudes whole plant (88.8%), Nepata curviflora leaf (88.8%), Nepata curviflora stem, and Verbascum leptostychum flower (99.9%). The minimum inhibitory concentration (MIC) was determined on plant extracts that showed high efficacy against the test organisms. The chance to find antimicrobial activities was more apparent in methanol rather than water extracts of the same indigenous plants of Lebanon, with higher antimicrobial activities in 20 microl methanol extract-discs in comparison to that present in the 10 microl discs (P < 0.05).     

Screening of Australian plants for antimicrobial activity against Campylobacter jejuni

Campylobacter jejuni is the most common cause of acute enteritis in humans, with symptoms such as diarrhoea, fever and abdominal cramps. In this study, 115 extracts from 109 Australian plant species were investigated for their antimicrobial activities against two C. jejuni strains using an in vitro broth microdilution assay. Among the plants tested, 107 (93%) extracts showed activity at a concentration between 32 and 1024 µg/mL against at least one C. jejuni strain. Seventeen plant extracts were selected for further testing against another six C. jejuni strains, as well as Campylobacter coli, Escherichia coli, Salmonella typhimurium, Bacillus cereus, Proteus mirabilis and Enterococcus faecalis. The extract from Eucalyptus occidentalis demonstrated the highest antimicrobial activity, with an inhibitory concentration of 32 µg/mL against C. jejuni and B. cereus. This study has shown that extracts of selected Australian plants possess antimicrobial activity against C. jejuni and thus may have application in the control of this organism in live poultry and retail poultry products. Copyright © 2011 John Wiley & Sons, Ltd.     

An ethnobotanical survey of Bauchi State herbal plants and their antimicrobial activity

A survey of medicinal plants used locally in the treatment of various diseases was carried out in Bauchi State-Nigeria. A total of 84 medicinal plants were listed. Preliminary antimicrobial activity of the aqueous extracts of the plants was investigated. The results indicated that out of 84 plants, 75 exhibited antimicrobial activity against one or more of the test organisms at a concentration of 200 mg/ml. The extracts were found to show potentially interesting activity against Proteus mirabilis, Pseudomonas aeruginosa, Staphylococcus aureus and Escherichia coli.     

In vitro antimicrobial activity of plants used in Cambodian traditional medicine

The purpose of the present study was to screen 27 plant species used in the traditional medicine of Cambodia for in vitro antibacterial and antifungal activities. Thirty-three methanolic extracts were tested against Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, Mycobacterium smegmatis and Candida albicans. Screened by disk diffusion assay, the extracts showed antimicrobial activity especially on Gram-positive bacteria. None of the crude methanolic extracts showed activity against P. aeruginosa. Twenty-five selected extracts were evaluated using a micro-dilution test. Harrisonia perforata (roots) and Hymenodictyon excelsum (bark) exhibited a bactericidal effect against S. aureus at a concentration of 500 microg/ml. Azadirachta indica (bark), Harrisonia perforata (roots and stem) and Shorea obtusa (roots) exhibited a bactericidal effect against M. smegmatis at 250 microg/ml.     

Medicinal plants of the Mapuche

A list of 136 plants used for medicinal purposes by the Mapuche Amerindians of Chile has been compiled. This is the first such list in English and is important due to the disappearance of Mapuche culture with increasing urbanisation. Some introduced plants have been incorporated into the traditional medicine of the Mapuche since the advent of European settlers but there is also a wealth of information about the uses of many indigenous species.     

Medicinal plants in Mozambique and their popular use

The authors give a review about plants used in the folk medicine of Mozambique, according to the literature and the personal experiences of the first author in dealing with people there. This paper shows their known active compounds and treatment of the therapeutical values as well as methods of application in Mozambique and in its neighbouring countries.     

Screening of medicinal plants of Rwanda (Central Africa) for antimicrobial activity

A series of 100 medicinal plants of Rwanda (282 plant samples) has been screened for antimicrobial activity against Bacillus subtilis, Candida albicans, Mycobacterium smegmatis, Pseudomonas aeruginosa, Salmonella gallinarum and Staphylococcus aureus. Thirty percent of the plants tested showed activity against one or more microorganisms.