Anupam Dikshit

Use of essential oil as botanical-pesticide against post harvest spoilage in Malus pumilo fruit

During antifungal screening of the essentialoils of some angiospermic plants, oil ofCymbopogon flexuosus showed potentbioactivity against dominant post harvestfungal pathogens. The minimum bioactiveconcentrations with fungicidal action of theoil was found to be 0.2 µl ml−1 for Alternaria alternata, 0.4 µlml−1 for Aspergillus flavus, A.fumigatus, A. niger, A. parasiticus,Cladosporium cladosporioides, Colletotrichumcapsici, C. falcatum, Curvularia lunata,Fusarium cerealis, F. culmorum, F. oxysporum,F. udum, Gloeosporium fructigenum, Penicilliumexpansum, P. italicum, P. implicatum, P. digitatum,P. minio-luteum, P. variable,and 0.5 µl ml−1 forBotrytis cinerea, Helminthosporium oryzae, H.maydis, Phoma violacea, Rhizopus nigricans.The oil exhibited potency against heavy doses(30 mycelial disc, each of 5 mm in diameter) ofinoculum at 1.0 µl ml−1 concentrations.The bioactivity of the oil was thermostable upto 100°C and lasted up to 48 months.The oil preparation did not exhibit anyphytotoxic effect on the fruit skins ofMalus pumilo up to 50 µlml−1 concentrations. In vivo trials of theoil as a fungicidal spray on Malus pumilofor checking the rotting of fruits, it showedthat 20 µl ml−1 concentration controls100% infection by pre-inoculation treatment,while in post-inoculation treatment, 30 µlml−1 concentration of fungicidal spraywas required for the 100% control of rotting.The fungicidal spray was found to be costeffective (INR 15/l), has long shelf life (48month) and was devoid of any adverse effects.Therefore, it can be used as a potential sourceof sustainable eco-friendly botanicalpesticide, after successfulcompletion of wide range trials.

Broad spectrum herbal therapy against superficial fungal infections

Skin disease associated with keratinized tissues in animal and human beings has been investigated. The essential oil of Eucalyptus pauciflora in vitro showed strong antifungal activity at 1.0 μl/ml against human pathogenic fungi, viz. Epidermophyton floccosum, Microsporum audouinii, M. canis, M. gypseum, M. nanum, Trichophyton mentagrophytes, T. rubrum, T. tonsurans and T. violaceum. The oil has heavy doses of inoculum potential at 1.0 μl/ml. Moreover, it did not exhibit any adverse effects on mammalian skin up to 5% concentrations. Further, we formulated the oil in the form of ointment ‘BSHT’ (broad spectrum herbal therapy) (1% v/v) and subjected it to topical testing on patients attending the outpatient department of M.L.N. Medical College, Allahabad. Fifty patients were selected on the basis of KOH-positive results and diagnosed as either tinea pedis, tinea corporis or tinea cruris. After the second week of treatment, all patients were KOH-negative. At the end of medication, 60% of patients recovered completely and 40% showed significant improvement from the disease. No KOH-negative cases of relapse were observed when patients were re-examined after 2 months following the end of treatment. Thus, the ointment can be exploited commercially after undergoing successful multicenter clinical trials, which are in progress.

Antifungal Evaluation of the Essential Oil of Cymbopogon pendulus (Nees ex Steud.) Wats. cv. Praman

During screening of some aromatic plants for fungitoxicity of their volatile oils, Cymbopogon pendulus (Nees ex Steud.) Wats. cv. Praman exhibited the strongest activity, completely inhibiting the mycelial growth of the test fungi Microsporum gypseum (Bodin) Guiart and Grigoraki and Trichophyton mentagrophytes (Robin.) Blanchard. The volatile oil distilled from the fresh leaves was found to be fungicidal at its minimum inhibitory concentration (MIC) of 200 μg/ml, inhibiting heavy inocula of the test fungi. During testing of its fungitoxic spectrum, it also inhibited mycelial growth of three other fungi and was found to be more active than some commercial drugs tested.

Management of Cosmetic Embarrassment Caused by Malassezia spp. with Fruticose Lichen Cladia Using Phylogenetic Approach

During anti-Malassezia screening of plants by CLSI broth microdilution method, Cladia aggregata (Swartz) Nyl. (family Cladoniaceae), a fruticose lichen from Sikkim (northeast Himalayan region), has been found effective at minimum inhibitory concentrations (mg/mL) of 2.72, 0.63, and 1.28 against yeast-like fungi namely, M. furfur, M. globosa and M. sympodialis, respectively. These test pathogens are responsible for pityriasis versicolor (PV) and seborrheic dermatitis (SD) in humans. We tried to establish the reason for variable MICs against various Malassezia spp. using bioinformatical tools, thereby reducing the cost of the experimentation. This is the first report on anti-Malassezia activity of C. aggregata and thus can serve as a potential source for the development of cosmaceuticals.

Studies on antidermatophytic activity of waste leaves of Curcuma longa L.

During antidermatophytic screening of some essential oils, Curcuma longa L. exhibited the strongest antifungal activity, completely inhibiting the mycelial growth of ringworm, caused by the fungi- Microsporum gypseum and Trichophyton mentagrophytes. The essential oil from leaves of Curcuma longa was fungicidal at 2.5 μl/ml at which it tolerated heavy doses of inoculum. The fungicidal activity of the oil was thermostable up to 80 °C and self life up to 24 months in storage. The oil also showed a broad fungitoxic spectrum, inhibiting the mycelial growth of other fungi, viz., Epidermophyton floccosum, M. nanum, T. rubrum, T. violaceum. Moreover, up to 5 % concentration it did not exhibit any adverse effect on mammalian skins. The oil has been formulated in the form of an ointment, 1 % w/v and subjected to topical testing on patients of the Out Patient Department (OPD) at Moti Lal Nehru Medical College, Allahabad. Patients were selected on the basis of KOHpositive results and diagnosed tenia corporis. After the second week of treatment, all patients were KOH- negative. At the end of medication, 75 % of patients recovered completely while 15 % showed significant improvement from the disease. The ointment thus, can be exploited commercially after ongoing successful clinical trials. Relationship of the dermatophytes to the toxicity of the oil vis-a-vis phylogeny using molecular data of the pathogens have also been discussed.

Prediction and validation of gold nanoparticles (GNPs) on plant growth promoting rhizobacteria (PGPR): a step toward development of nano-biofertilizers

Abstract Several soil microbes are present in the rhizosphere zone, especially plant growth promoting rhizobacteria (PGPR), which are best known for their plant growth promoting activities. The present study reflects the effect of gold nanoparticles (GNPs) at various concentrations on the growth of PGPR. GNPs were synthesized chemically, by reduction of HAuCl4, and further characterized by UV-Vis spectroscopy, X-ray diffraction technique (XRD), and transmission electron microscopy (TEM), etc. The impact of GNPs on PGPR was investigated by Clinical Laboratory Standards Institute (CLSI) recommended Broth-Microdilution technique against four selected PGPR viz., Pseudomonas fluorescens, Bacillus subtilis, Paenibacillus elgii, and Pseudomonas putida. Neither accelerating nor reducing impact was observed in P. putida due to GNPs. On the contrary, significant increase was observed in the case of P. fluorescens, P. elgii, and B. subtilis, and hence, GNPs can be exploited as nano-biofertilizers.

Modified Spore Germination Inhibition Technique for Evaluation of Candidate Fungitoxicant (Eucalyptus spp.)

The technique of spore germination inhibition has been modified by introducing the mathematical model for standardization of inoculum, reducing the cost as well as observation period thereby making the technique simple and no chance of contamination for the evaluation of candidate fungitoxicant(s). The present technique is compared with prevalent poisoned food technique and we found that quantitative results are almost the same. Amongst the candidate essential oils extracted from Eucalyptus citriodora, E. dalrympleana, E. laveopinea, E. pauciflora, only the oil of E. citriodora at 1000 mg/ml showed complete inhibition of spore germination of the storage spoilage test fungus Penicillium italicum. The oil of E. dalrympleana and E. laveopinea showed fungistatic toxicity against the test fungus at 3000 mg/ml but the oil of E. laveopinea showed partial inhibition at 3000 mg/ml. The oil of E. citriodora at 1000 mg/ml exhibited fungicidal nature and withstood heavy inoculum. Since the oil at sublethal concentration exhibited no abnormalities at morphological level, the total picture can be drawn only after undertaking the work on cytological and at enzymatic level against the test fungus.

Copper oxide nanoparticles: an antidermatophytic agent for Trichophyton spp.

Abstract Copper oxide (CuO) is one of the most important transition metal oxides due to its unique properties. It is used in various technological applications such as high critical temperature, superconductors, gas sensors, in photoconductive applications and so on. Recently, it has been used as an antimicrobial agent against various pathogenic bacteria. In the present investigation, we studied the structural and antidermatophytic properties of CuO nanoparticles (NPs) synthesized by a precipitation technique. Copper sulfate was used as a precursor and sodium hydroxide as a reducing agent. Scanning electron microscopy (SEM) showed flower-shaped CuO NPs and X-ray diffraction (XRD) pattern showed the crystalline nature of CuO NPs. These NPs were evaluated against two prevalent species of dermatophytes, i.e. Trichophyton rubrum and T. mentagrophytes by using the broth microdilution technique. Further, the NPs activity was also compared with synthetic sertaconazole. Although better antidermatophytic activity was exhibited with sertaconazole as compared to NPs, being synthetic, sertaconazole may not be preferred, as it shows different adverse effects. Trichophyton mentagrophytes is more susceptible to NPs than T. rubrum. A phylogenetic approach was applied for predicting differences in susceptibility of pathogens.

Detoxification and Tolerance of Heavy Metals in Plants

Abstract Plant growth and metabolisms are regulated by some heavy metals found in Earths crust because they are active constituents of various enzymes. However, their increased concentration may lead to different toxic effects, inhibiting plant growth and development. There are some plants that are capable of surviving in the presence of heavy metals, apparently by adapting the mechanism that involved in common homeostasis as well as removal of metal ions. Plants have diverse mechanisms for metal detoxification, enabling them to tolerate heavy metal stress. The defense systems against heavy metal stress include mycorrhizae, cellular exudates, plasma membrane, heat shock proteins, phytochelatins (PCs), metallothioneins (MTs), organic acids, and amino acids. All the mechanism involved the tolerance of heavy metal concentration at cellular level to avoid the negative impacts. Extracellular plants include roles for mycorrhizae and extracellular exudates in the plasma membrane either by dropping by absorption of heavy metal or by inducing the efflux pumping of metal ions. On the other hand, intracellularly heat shock proteins, MTs, organic acids, amino acids, and PCs also play a vital role in tolerance of different heavy metals. Few metal transporters have been identified in the past few years that actively participate in tolerance of metal specificity. Enhanced application of molecular genetics has shown their eminent contribution in understanding the mechanism of heavy metal tolerance in plants.

A comparative analysis of in vitro growth inhibition of waterborne bacteria with bioactive plant Lippia nodiflora L. and camphor

AbstractIn the current scenario, due to global deterioration of the environment and climate change, among them water pollution possesses serious threat to most of the populace. Waterborne pathogenic bacteria like Escherichia coli, Vibrio cholerae, Salmonella typhimurium, Klebsiella pneumoniae, etc. are responsible for several diseases such as diarrhoea, cholera, salmonellosis, etc. In order to overcome these waterborne bacterial diseases and for purification of water, plants have been of great use for their potential role from very ancient times. The present study deals with the Clinical & Laboratory Standards Institute (CLSI)-recommended broth microdilution antibacterial susceptibility assay of waterborne bacterial pathogens against Lippia nodiflora L. petroleum ether (LNPE) and ethanolic extracts (LNEE) prepared from the leaves and flowers together of Lippia nodiflora (Verbenaceae), in comparison to camphor. Growth inhibition of tested bacterial pathogens was recorded in from of IC50 and MIC values were...