Savarimuthu Ignacimuthu

In vitro antibacterial activity of some plant essential oils

Background:To evaluate the antibacterial activity of 21 plant essential oils against six bacterial species.Methods:The selected essential oils were screened against four gram-negative bacteria (Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Proteus vulgaris) and two gram-positive bacteria Bacillus subtilis and Staphylococcus aureus at four different concentrations (1:1, 1:5, 1:10 and 1:20) using disc diffusion method. The MIC of the active essential oils were tested using two fold agar dilution method at concentrations ranging from 0.2 to 25.6 mg/ml.Results:Out of 21 essential oils tested, 19 oils showed antibacterial activity against one or more strains. Cinnamon, clove, geranium, lemon, lime, orange and rosemary oils exhibited significant inhibitory effect. Cinnamon oil showed promising inhibitory activity even at low concentration, whereas aniseed, eucalyptus and camphor oils were least active against the tested bacteria. In general, B. subtilis was the most susceptible. On the other hand, K. pneumoniae exhibited low degree of sensitivity.Conclusion:Majority of the oils showed antibacterial activity against the tested strains. However Cinnamon, clove and lime oils were found to be inhibiting both gram-positive and gram-negative bacteria. Cinnamon oil can be a good source of antibacterial agents.

Medicinal plants used by traditional healers in Kancheepuram District of Tamil Nadu, India

An ethnobotanical survey was undertaken to collect information from traditional healers on the use of medicinal plants in Kancheepuram district of Tamil Nadu during October 2003 to April 2004. The indigenous knowledge of local traditional healers and the native plants used for medicinal purposes were collected through questionnaire and personal interviews during field trips.The investigation revealed that, the traditional healers used 85 species of plants distributed in 76 genera belonging to 41 families to treat various diseases. The documented medicinal plants were mostly used to cure skin diseases, poison bites, stomachache and nervous disorders. In this study the most dominant family was Euphorbiaceae and leaves were most frequently used for the treatment of diseases.This study showed that many people in the studied parts of Kancheepuram district still continue to depend on medicinal plants at least for the treatment of primary healthcare. The traditional healers are dwindling in number and there is a grave danger of traditional knowledge disappearing soon since the younger generation is not interested to carry on this tradition.

Antimicrobial activity of some ethnomedicinal plants used by Paliyar tribe from Tamil Nadu, India

BackgroundAntimicrobial activity of 18 ethnomedicinal plant extracts were evaluated against nine bacterial strains (Bacillus subtilis, Staphylococcus aureus, Staphylococcus epidermidis, Enterococcus faecalis, Escherichia coli, Klebsiella pneumonia, Pseudomonas aeruginosa, Ervinia sp, Proteus vulgaris) and one fungal strain (Candida albicans). The collected ethnomedicinal plants were used in folk medicine in the treatment of skin diseases, venereal diseases, respiratory problems and nervous disorders.MethodsPlants were collected from Palni hills of Southern Western Ghats and the ethnobotanical data were gathered from traditional healers who inhabit the study area. The hexane and methanol extracts were obtained by cold percolation method and the antimicrobial activity was found using paper disc diffusion method. All microorganisms were obtained from Christian Medical College, Vellore, Tamil Nadu, India.ResultsThe results indicated that out of 18 plants, 10 plants exhibited antimicrobial activity against one or more of the tested microorganisms at three different concentrations of 1.25, 2.5 and 5 mg/disc. Among the plants tested, Acalypha fruticosa, Peltophorum pterocarpum, Toddalia asiatica,Cassia auriculata, Punica granatum and Syzygium lineare were most active. The highest antifungal activity was exhibited by methanol extract of Peltophorum pterocarpum and Punica granatum against Candida albicans.ConclusionThis study evaluated the antimicrobial activity of the some ethnomedicinal plants used in folkloric medicine. Compared to hexane extract, methanol extract showed significant activity against tested organisms. This study also showed that Toddalia asiatica, Syzygium lineare, Acalypha fruticosa and Peltophorum pterocarpum could be potential sources of new antimicrobial agents.

Mechanisms of plant defense against insect herbivores

Plants respond to herbivory through various morphological, biochemicals, and molecular mechanisms to counter/offset the effects of herbivore attack. The biochemical mechanisms of defense against the herbivores are wide-ranging, highly dynamic, and are mediated both by direct and indirect defenses. The defensive compounds are either produced constitutively or in response to plant damage, and affect feeding, growth, and survival of herbivores. In addition, plants also release volatile organic compounds that attract the natural enemies of the herbivores. These strategies either act independently or in conjunction with each other. However, our understanding of these defensive mechanisms is still limited. Induced resistance could be exploited as an important tool for the pest management to minimize the amounts of insecticides used for pest control. Host plant resistance to insects, particularly, induced resistance, can also be manipulated with the use of chemical elicitors of secondary metabolites, which confer resistance to insects. By understanding the mechanisms of induced resistance, we can predict the herbivores that are likely to be affected by induced responses. The elicitors of induced responses can be sprayed on crop plants to build up the natural defense system against damage caused by herbivores. The induced responses can also be engineered genetically, so that the defensive compounds are constitutively produced in plants against are challenged by the herbivory. Induced resistance can be exploited for developing crop cultivars, which readily produce the inducible response upon mild infestation, and can act as one of components of integrated pest management for sustainable crop production.

Antibacterial activity of some folklore medicinal plants used by tribals in Western Ghats of India.

A series of 30 Indian folklore medicinal plants used by tribal healers to treat infections, were screened for antibacterial properties at 10 mg/ml concentration by using disc diffusion method against Bacillus subtilis, Escherichia coli, Klebsiella aerogenes, Proteus vulgaris, Pseudomonas aerogenes and Staphylococcus aureus. Twenty plant species showed activity against one or more species of bacteria used in this assay; among them the leaf extracts of Cassia occidentalis and Cassia auriculata exhibited significant broad spectrum activity against B. subtilis and S. aureus. Ten plant species were not found active against all tested bacteria. These results were compared with results obtained using standard antibiotics, chloramphenicol (30 microg/disc) and streptomycin (30 microg/disc) which served as a reference for inhibition zone diameter.

Screening of 34 Indian medicinal plants for antibacterial properties.

A total of 34 plant species belonging to 18 different families, selected on the basis of folklore medicinal reports practised by the tribal people of Western Ghats, India, were assayed for antibacterial activity against Escherichia coli, Klebsiella aerogenes, Proteus vulgaris, and Pseudomonas aerogenes (gram-negative bacteria) at 1000-5000 ppm using the disc diffusion method. Of these 16 plants showed activity; among them Cassia fistula, Terminalia arjuna and Vitex negundo showed significant antibacterial activity against the tested bacteria. Our findings confirm the traditional therapeutic claims for these herbs.

Ethnobotanical investigations among tribes in Madurai District of Tamil Nadu (India)

BackgroundAn ethnobotanical survey was carried out to collect information on the use of medicinal plants in Southern Western Ghats of India (Madurai district, Tamil Nadu). Information presented in this paper was gathered from the paliyar tribes using an integrated approach of botanical collections, group discussions and interviews with questionnaires in the years 1998 – 1999. The informants interviewed were 12 among whom 4 were tribal practitioners.ResultsA total of 60 ethnomedicinal plant species distributed in 32 families are documented in this study. The medicinal plants used by paliyars are listed with Latin name, family, local name, parts used, mode of preparation and medicinal uses. Generally, fresh part of the plant was used for the preparation of medicine.ConclusionWe observed that the documented ethnomedicinal plants were mostly used to cure skin diseases, poison bites, stomachache and nervous disorders. The results of this study showed that these tribal people still depend on medicinal plants in Madurai district forest areas.

Ethnobotanical survey of medicinal plants commonly used by Kani tribals in Tirunelveli hills of Western Ghats, India.

ETHNOPHARMACOLOGICAL RELEVANCE For thousands of years, medicinal plants have played an important role throughout the world in treating and preventing a variety of diseases. Kani tribal people in Tirunelveli hills still depend on medicinal plants and most of them have a general knowledge of medicinal plants which are used for first aid remedies, to treat cough, cold, fever, headache, poisonous bites and some simple ailments. AIM OF THE STUDY The present study was initiated with an aim to identify traditional healers who are practicing herbal medicine among the Kani tribals in Tirunelveli hills of Western Ghats, India and quantitatively document their indigenous knowledge on the utilization of medicinal plants particularly most common ethnomedicinal plants. METHODS Field study was carried out over a period of 4 years in Tirunelveli hills. The ethnomedicinal information was collected through interviews among the Kani traditional healers. The collected data were analyzed through use value (UV), informant consensus factor (F(ic)), fidelity level (FL) and relative importance (RI). RESULTS A total of 90 species of plants distributed in 83 genera belonging to 52 families were identified as commonly used ethnomedicinal plants by the Kani traditional healers in Tirunelveli hills for the treatment of 65 types of ailments. These ailments were categorized into 15 ailment categories based on the body systems treated. Leaves were the most frequently used plant parts and most of the medicines were prepared in the form of paste and administered orally. F(ic) values of the present study indicated that there was a high agreement in the use of plants in the treatment of jaundice and diabetes among the users. Dermatological infections/diseases and gastro-intestinal disorders had highest use-reports and 29 species of plants had the highest fidelity level of 100%. The most important species according to their use value were Gymneme sylvestre (2.00), Melia azedarach, Murraya koenigii, Syzygium cumini and Terminalia chebula (1.83). CONCLUSION As a result of the present study we can recommend the plants Alpinia galanga, Azadirachta indica, Calophyllum inophyllum, Gymnema sylvestre, Leucas aspera, M. azedarach, Mollugo nudicaulis, Ocimum tenuiflorum, S. cumini, T. chebula and Tribulus terrestris (with high UV and RI values), Bambusa arundinacea, Datura metel, Evolvulus nummularius, Opuntia dillenii and Physalis minima (newly reported claims with highest FL) for further ethnopharmacological studies for the discovery of potential new drugs.

Antidiabetic and antilipidemic effect of eremanthin from Costus speciosus (Koen.)Sm., in STZ-induced diabetic rats

The increasing prevalence of diabetes mellitus worldwide is an issue of major socio-economic concern. Diabetes mellitus is a complex and a multifarious group of disorders that disturbs the metabolism of carbohydrates, fat and protein. Medicinal plants play an important role in the management of diabetes mellitus especially in developing countries. Costus speciosus is widely used in Indian medicine to treat various diseases. Eremanthin was isolated from C. speciosus. The structure was identified using gas chromatography-mass spectrometry (GC-MS) analysis. Eremanthin was administered to streptozotocin (STZ) (50mg/kg bw) induced diabetic male Wistar rats at different doses (5, 10, 20mg/kg bw) for 60 days. Plasma glucose level was significantly (p<0.05) reduced in a dose dependent manner when compared to the control. In addition, oral administration of eremanthin (20mg/kg bw) significantly decreased glycosylated hemoglobin (HbA(1c)), serum total cholesterol, triglyceride, LDL-cholesterol and at the same time markedly increased plasma insulin, tissue glycogen, HDL-cholesterol and serum protein. Eremanthin also restored the altered plasma enzyme (aspartate aminotransferase, alanine aminotransferase, lactate dehydrogenase, alkaline phosphatase and acid phosphatase) levels to near normal. Results of this experimental study indicated that eremanthin possessed hypoglycemic and hypolipidemic activities and hence it could be used as a drug for treating diabetes.

Antibacterial and antifungal activity of Flindersine isolated from the traditional medicinal plant, Toddalia asiatica (L.) Lam.

AIM OF THE STUDY The leaves and root of Toddalia asiatica (L.) Lam. (Rutaceae) are widely used as a folk medicine in India. Hexane, chloroform, ethyl acetate, methanol and water extracts of Toddalia asiatica leaves and isolated compound Flindersine were tested against bacteria and fungi. MATERIALS AND METHODS Antibacterial and antifungal activities were tested against bacteria and fungi using disc-diffusion method and minimum inhibitory concentrations (MICs). The compound was confirmed using X-ray crystallography technique. RESULTS Antibacterial and antifungal activities were observed in ethyl acetate extract. One active principle Flindersine (2,6-dihydro-2,2-dimethyl-5H-pyrano [3,2-c] quinoline-5-one-9cl) was isolated from the ethyl acetate extract. The MIC values of the compound against bacteria Bacillus subtilis (31.25 microg/ml), Staphylococcus aureus (62.5 microg/ml), Staphylococcus epidermidis (62.5 microg/ml), Enterococcus faecalis (31.25 microg/ml), Pseudomonas aeruginosa (250 microg/ml), Acinetobacter baumannii (125 microg/ml) and fungi Trichophyton rubrum 57 (62.5 microg/ml), Trichophyton mentagrophytes (62.5 microg/ml), Trichophyton simii (62.5 microg/ml), Epidermophyton floccosum (62.5 microg/ml), Magnaporthe grisea (250 microg/ml) and Candida albicans (250 microg/ml) were determined. CONCLUSIONS Ethyl acetate extract showed promising antibacterial and antifungal activity and isolated compound Flindersine showed moderate activity against bacteria and fungi.