Browsing by Author "Chandra Shekhar Prasad"

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Antimycotic and antiaflatoxigenic potency of Adenocalymma alliaceum Miers. on fungi causing biodeterioration of food commodities and raw herbal drugs
(2008) Ravindra Shukla; Ashok Kumar; Chandra Shekhar Prasad; Bhawana Srivastava; Nawal Kishore Dubey
This study characterized the antifungal and antiaflatoxigenic efficacy of an aqueous extract of Adenocalymma alliaceum against fungal isolates that cause biodeterioration of cereal grains, legume seeds, dry fruits, fresh fruits, and raw herbal drugs during storage and transportation. Fungal species that cause biodeterioration were isolated from stored food and drug commodities by serial dilutions. A poisoned food technique was adopted to assess fungitoxicity of the plant extract against fungal isolates. Minimum inhibitory concentration (MIC) and minimum fungicidal concentration (MFC) of extracts against two dominant storage fungi, Aspergillus flavus and Aspergillus niger, were superior to those of two commonly used synthetic fungicides. Aflatoxin B1 synthesis was inhibited at low extract concentrations in SMKY medium. Germination of legume seeds was unaffected by the extract application but rather seedling growth was enhanced. Hence the aqueous extract of A. alliaceum possessed a wide spectrum of fungitoxicity against fungi associated with deterioration of food commodities and herbal drugs. In addition, it possessed antiaflatoxigenic activity and was non-phytotoxic. © 2008 Elsevier Ltd. All rights reserved.
Assessment of Thymus vulgaris L. essential oil as a safe botanical preservative against post harvest fungal infestation of food commodities
(2008) Ashok Kumar; Ravindra Shukla; Priyanka Singh; Chandra Shekhar Prasad; Nawal Kishore Dubey
A total of 14 odoriferous angiospermic essential oils were tested against the toxigenic strain of Aspergillus flavus. The essential oil of Thymus vulgaris L. showed highest antifungal efficacy. The thyme oil absolutely inhibited the mycelial growth of A. flavus at 0.7 μl ml- 1 and exhibited a broad fungitoxic spectrum against eight different food contaminating fungi viz. Fusarium oxysporum, Cladosporium herbarum, Curvularia lunata, Aspergillus terreus, Aspergillus niger, Aspergillus fumigatus, Alternaria alternata and Botryodiploidia theobromae. The oil also showed significant antiaflatoxigenic efficacy as it completely arrested the aflatoxin B1 production at 0.6 μl ml- 1. Thyme oil as fungitoxicant was also found superior over most of the prevalent synthetic fungicides. The LC50 of thyme oil against mice was recorded as 7142.85 μl kg- 1 body weight indicating its non-mammalian toxicity and strengthening its safe exploitation as preservative for stored food commodities. The findings recommend the thyme oil as potential botanical preservative in eco-friendly control of biodeterioration of food commodities during storage. Industrial relevance: The thyme essential oil may be recommended for large scale application as a plant based preservative for stored food items because of its strong antifungal as well as antiaflatoxigenic efficacy. Because of broad antimicrobial spectrum, more efficacy over prevalent synthetic preservatives as well as non-mammalian toxicity, the thyme essential oil may be formulated as a safe and economical plant based preservative against post harvest fungal infestation and aflatoxin contamination of food commodities. © 2008 Elsevier Ltd. All rights reserved.
Efficacy of Acorus calamus L. leaves and rhizome on mortality and reproduction of Callosobruchus chinensis L. (Coleoptera: Bruchidae)
(2009) Ravindra Shukla; Ashok Kumar; Chandra Shekhar Prasad; Bhawana Srivastava; Nawal Kishore Dubey
Laboratory and field experiments were conducted to investigate the bioefficacy of sweet flag (Acorus calamus) against the pulse beetle Callosobruchus chinensis, which infests stored chick pea seeds. Dried powders of the leaf and rhizome as well as their extracts in methanol (ME) and petroleum ether (PEE) were evaluated as bio-insecticides against the beetle. Rhizome powder (5 mg/g seed) was found to be more efficacious, causing 100% mortality, than leaf powder (20 mg/g seed), showing 91.1% mortality. Rhizome powders also showed 100% ovicidal activity and thus completely inhibited F1 emergence at a lower dose than that of leaf powders. The ME and PEE of leaves and rhizome showed 12 to 100% mortality. The percentage of egg laying decreased from 12.8 to 100 with increasing doses of powders and extracts. No F1 adult emerged at 0.3-0.4mg/g ME of leaves and rhizome and PEE of rhizome. In six-month field trials, all treatments at laboratory doses proved efficacious (75-98%) over organophosphate insecticide malathion (74.4%) in terms of feeding deterrence. Powder- and extract-treated chick pea seeds did not lose their viability and germinated at 100%, similar to control seeds. It was concluded that leaf and rhizome powders and their solvent extracts showed significant mortality, and inhibition of egg laying and F1 emergence of C. chinensis at varying concentrations. Hence, the leaves and rhizome of A. calamus may be recommended as admixtures in the integrated management of beetle infestation of pulse seeds during storage.
In vitro and in vivo antifungal activity of essential oils of Cymbopogon martini and Chenopodium ambrosioides and their synergism against dermatophytes
(2010) Chandra Shekhar Prasad; Ravindra Shukla; Ashok Kumar; N.K. Dubey
The present study was carried out to evaluate the antifungal efficacy of essential oils (EO) of Cymbopogon martini, Chenopodium ambrosioides and of their combination against dermatophytes and some filamentous fungi in vitro as well as in vivo using a guinea pig model. The minimum inhibitory concentrations of EOs and of their combination were found between 150 and 500 ppm, while those of known antifungal drugs ranged from 1000 to 5500 ppm. EO ointments were prepared and applied against induced ringworm in guinea pig model and disease removal was observed in 7-21 days, and the hair samples showed negative results for fungal culture in a time-dependent manner after the application of EO ointments. Chemical constituents of EOs were determined by GC-MS. Both the EOs and their combination displayed strong antifungal effects. The results provide a scientific validation for the use of these EOs in the treatment of dermatophyte infections and may be recommended as an alternative to synthetic drug for topical application. © 2009 Blackwell Verlag GmbH.