Padma Kumar

In vitro antifungal potency of some plant extracts against Fusarium oxysporum

In an approach towards the development of ecofriendly antifungal compounds for controlling plant diseases caused by Fusarium oxysporum, different extracts of three weed plants, namely, Capparis decidua, Lantana camara and Tridax procumbens, were tested for their antifungal potential. The spore germination/spore counting technique was followed for the evaluation of the antibiotic properties of the extracts at three different concentrations. Results revealed that the free flavonoids and sterols of T. procumbens (flower) and bound flavonoids of C. decidua (fruit and stem) totally inhibited spore germination of the fungi (100%). The antifungal components from these plants could be used in developing novel fungicides (biopesticides) for the diseases caused by F. oxysporum (plant pathogen). Key words: Capparis decidua, Fusarium oxysporum, Lantana camara, percentage spore inhibition, Tridax procumbens

Evaluation of Antimicrobial Efficacy of Flavonoids of Withania Somnifera L.

In the present study antimicrobial activity of Withania somnifera L. Dunal (Solanaceae) has been evaluated against selected pathogens. Free and bound flavonoids of different parts (root, stem, leaf and fruit) of W. somnifera have been studied for their antimicrobial activity using disc diffusion assay against three Gram negative bacteria (Escherichia coli MTCC 46, Proteus mirabilis MTCC 3310 and Pseudomonas aeruginosa MTCC 1934), one Gram positive bacteria (Staphylococcus aureus MTCC 3160) and three fungi (Candida albicans MTCC 183, Aspergillus flavus MTCC 277 and Aspergillus niger MTCC 282). Minimum inhibitory concentration (MIC) of the extracts was evaluated through micro broth dilution method, while minimum bactericidal/fungicidal concentration was determined by sub culturing the relevant samples. C. albicans was found to be the most susceptible organism followed by S. aureus, P. mirabilis, E. coli and P. aeruginosa. Out of the tested organisms, A flavus and A. niger were observed to be resistant as none of the tested extracts showed activity against them. Total activity (TA) of extracts (ml/g) against each sensitive pathogens was also evaluated. Bound flavonoid extract of root showed best activity against C. albicans (IZ 30, MIC 0.039, MFC 0.039, respectively). However all the microorganisms were found to be sensitive against the extracts tested. Total activity of bound flavonoid extract of root was found to be same for E.coli, P. mirabilis, S. aureus and C. albicans (153.84 ml/g). Results of the present study reveal that extracts of W. somnifera showing great antimicrobial potential against test microorganisms may be exploited for future antimicrobial drugs.

Antimicrobial Activity of Extracts of Marchantia polymorpha

The crude methanol and flavonoid (free and bound) extracts of Marchantia polymorpha L. (Marchantiaceae) were screened against three bacterial strains, viz., Escherichia coli, Proteus mirabilis (Gram negative), and Staphylococcus aureus (Gram positive), and four fungal strains, viz., Aspergillus flavus, A. niger, Candida albicans, and Trychophyton mentagrophytes. Disk diffusion and microbroth dilution techniques were performed for evaluation of antimicrobial activity of the extracts. Total activity of extracts (mL) against each sensitive pathogen was also evaluated. Methanol and free flavonoid extract showed best activity against S. aureus (IZ 20.6 and 19.6 mm, MIC 0.281 and 0.312 mg/mL, MBC 1.125 and 0.312 mg/mL, respectively). However, all the microorganisms were found to be sensitive against the extracts tested. Total activity for P. mirabilis and S. aureus for methanol extract was found to be the same (124 mL), but was maximum for free flavonoid against C. albicans (199 mL). The current study indicates that the tested extracts of Marchantia polymorpha may be exploited for antimicrobial drugs in the future.

Treatment of dermatophytosis by a new antifungal agent 'apigenin'.

Dermatophytes are the most common causative agents of cutaneous mycosis and remain a major public health problem in spite of the availability of an increasing number of antifungal drugs. It was, therefore considered necessary to pursue the screening of different extracts (compounds) of selected traditional medicinal plants reportedly having antidermatophyte potential. The aim of this study was to isolate and identify specific compound from the most active extract (free flavonoid) of stem of Terminalia chebula of the selected plants to treat dermatophytosis induced on experimental mice. Mice which were experimentally induced with Trichophyton mentagrophytes were grouped in six of five animals each. To treat the lesions on infected mice, two concentrations of isolated apigenin ointment, i.e. 2.5 mg g−1 (Api I) and 5 mg g−1 (Api II), and terbinafine (standard) of concentration 5 mg g−1 were used. Complete recovery from the infection was recorded on 12th day of treatment for reference drug Terbinafine and Api II (5 mg g−1) concentration of ointment, whereas Api I (2.5 mg g−1) ointment showed complete cure on 16th day of treatment. Fungal burden was also calculated by culturing skin scraping from infected mices of different groups. Apigenin has shown potency as the infected animals recover completely by Api II comparable to the standard drug in 12th day. So Apigenin can be explored as an antifungal agent in the clinical treatment of dermatophytosis in future.

Biological activity of alkaloids from Solanum dulcamara L.

Alkaloids are well known for their antimicrobial activity. Though all natural alkaloids come from plants, not all plants produce alkaloids. Plants of the Solanaceae family are known for their high alkaloid content. Alkaloids are found in all plant parts like roots, stems, leaves, flowers, fruits and seeds. In the present study, those plant parts of Solanum dulcamara were selected which have been reported to produce a high content of a specific alkaloid: solanine (from unripe fruits), solasodine (from flowers) and β-solamarine (from roots). These alkaloids were extracted from various parts of S. dulcamara by well-established methods and were screened for their antibacterial activity. Human pathogenic bacteria, viz., Enterobacter aerogenes, Escherichia coli, Staphylococcus aureus, were selected for the study. All three alkaloids inhibited the growth of E. coli and S. aureus. However, no significant activity was observed against E. aerogenes. Minimum inhibitory concentration and minimum bactericidal concentration were also evaluated.

Bioefficacy of Lantana camara L. against some human pathogens

Antimicrobial efficacy of flavonoids (free and bound) and crude alkaloids of Lantana camara L. was determined by disc diffusion assay against three bacteria (Escherichia coli, Proteus mirabilis, and Staphylococcus aureus) and two fungi (Candida albicans and Trichophyton mentagrophytes). Minimum inhibitory concentration, minimum bactericidal/fungicidal concentration and total activity were also studied. Most susceptible microorganism in the present study was C. albicans followed by P. mirabilis, S. aureus, E. coli, and T. mentagrophytes. The range of minimum inhibitory concentration of tested extracts was 0.039-0.625 mg/ml while minimum bactericidal/fungicidal concentration ranged from 0.078-1.25 mg/ml. Six extracts out of eleven tested showed same values of minimum inhibitory concentration and minimum bactericidal/fungicidal concentration, while rest showed higher values of minimum bactericidal/fungicidal concentration. Highest total activity (120.51 ml/g) was observed for bound flavonoids of root against Candida albicans and Staphylococcus aureus. Results of the present investigation indicate that Lantana camara has good antimicrobial activity with low range of minimum inhibitory concentration hence can be exploited for future plant based antimicrobial drugs.

Broad spectrum antidermatophytic drug for the control of tinea infection in human beings

During antifungal evaluation of various plant extracts, free and bound flavonoids of Piper betle were found to be most effective as an antidermatophytic against human pathogenic dermatophytes Trichophyton rubrum, Trichophyton mentagrophytes, Microsporum gypseum and Candida albicans. Dermatophytic fungi cause both superficial and internal mycoses. These mycoses, although normally not lethal, are unpleasant and difficult to cure and cause considerable financial losses. Earlier workers prove that allopathic drugs are still found effective against dermatomycoses, but these drugs could not be accepted as a routine treatment for every case, because they are expensive and require long treatment. It is almost unaffordable by middle and lower class people. In view of such prospects and constraints, our aim was to explore more new compounds of plant origin for controlling dermatophytic infections. Author explored water, methanolic and flavonoid extracts for screening as antidermatophytic agent. Plant extracts that showed good results in vitro were selected for clinical studies. The study may give cheaper treatment for medium and lower class patients suffering with tinea and may provide them much relief. Well‐established paper disc method was used for the screening of different extracts of their antidermatophytic activity. Moreover, it did not exhibit any adverse side effect on mammalian skin. Flavonoids in the form of ointment Pi be I and Pi be II were subjected to topical testing on patients attending out patients department of S.M.S. Hospital, Jaipur, India. Patients were diagnosed as tinea corporis, tinea capitis, tinea manum or tinea pedis. All patients showed positive potassium hydroxide (KOH) results at the beginning of trial. Patients between the ages of 3 months to 58 years were enrolled. At the end of treatment, while 64% of patients cured completely, 24% showed significant improvement and 12% showed little improvement from the disease. Allopathic treatment took 4–8 weeks when compared with only 1–5 weeks taken by Pi be I and Pi be II ointments. The ointment, thus not only showed maximum affectivity but was also found to be a better and cost effective alternative to allopathic drug for tinea infections. The acceptability of alternative medicines, particularly herbal medicines, has now become a critical need of the times.

Extraction, gas chromatography-mass spectrometry analysis and screening of fruits of Terminalia chebula Retz. for its antimicrobial potential

Background: Terminalia chebula is called the “king of medicines” in Tibet and is always listed first in the Ayurvedic meteria medica because of its extraordinary powers of healing. Objective: Identification, isolation and screening of pyrogallol which are responsible for antimicrobial property of fruits of Terminalia chebula. Materials and Methods: Ethyl acetate fraction of fruits of Terminalia chebula was subjected to Gas chromatography–mass spectrometry (GC-MS) for the components present in the extract. Results: Sixty four constituents were identified out of which kaempferol-3-O-rutinoside flavonoid and Vitamin E has been detected for the first time in fruits of this plant. Pyrogallol (46.26%) which was the major component of the extract in GC-MS analysis was isolated and screened for antimicrobial activity against selected test pathogens by Disc Diffusion Assay. Crude ethyl acetate fraction of the fruits was showing the same activity potential as was observed for pure pyrogallol which was the major component as per GC-MS analysis. The most sensitive species among the bacteria was Enterobacter aerogenes with highest inhibition zone (IZ = 31 mm; AI = 1.409 ± 0.046) even at minimum inhibitory concentration (0.039 mg/ml). Conclusion: Hence activity shown by crude ethyl acetate fraction might be due to pyrogallol present in the extract. On the basis of results it can be advocate that achieved crude ethyl acetate fraction can be explored for preparing antimicrobial drugs in future for the infectious caused by the pathogens tested in the study.

Antimicrobial flavonoids from Tridax procumbens

Callus culture of Tridax procumbens has been established on Murashige and Skoogs medium supplemented with NAA and BAP from nodal segments. Free and bound flavonoids were extracted from 2, 4, 6 and 8 weeks old calli by a well-established method. These free flavonoids were then screened against Staphylococcus aureus (bacteria) and Candida albicans (yeast) for their antimicrobial potential. Minimum inhibitory concentration, minimum bactericidal/fungicidal concentrations and total activity were also evaluated. Apigenin, quercetin and kaempferol were identified from free flavonoids of 4 weeks old callus (most active) through, thin layer chromatography, (TLC) preparative TLC, MP and IR spectral studies.

Phytochemical study and screening for antimicrobial activity of flavonoids of Euphorbia hirta

Objective: This study aims to phytochemical and antimicrobial study of Euphorbia hirta Euphorbiaceae). Materials and Methods: Antimicrobial activity of flavonoids (free and bound) of Euphorbia hirta L. was determined by disc diffusion assay against four bacteria (Escherichia coli, Pseudomonas aeruginosa, Proteus mirabilis, and Staphylococcus aureus) and four fungi (Aspergillus flavus, Aspergillus niger, Trichophyton mentagrophytes, and Candida albicans). Minimum inhibitory concentration (MIC) of the extract was evaluated through micro broth dilution method, while minimum bactericidal/fungicidal concentration was determined by subculturing the relevant samples. Total activity (TA) of extracts against each sensitive pathogen was also evaluated. Results: Out of fungi; A. flavus, A. niger, and T. mentagrophytes were found to be resistant, against which none of the tested extracts showed activity. Bound flavonoids extract of root showed best activity against C. albicans (inhibition zone (IZ) 27.66, MIC 0.039, minimum fungicidal concentration (MFC) 0.039). TA of free flavonoid extract of root was found to be the same for P. mirabilis and S. aureus (192.30 ml/g). Two flavonoids quercetin and kaempferol were identified in the bound flavonoids of stem extract which showed activity against all the microorganisms. Conclusion: Results of the present investigation indicate that E. hirta has good antimicrobial activity with low range of MIC, hence can be exploited for future plant-based antimicrobial drugs.