Chemically characterized Cymbopogon martinii (Roxb.) Wats. essential oil for shelf life enhancer of herbal raw materials based on antifungal,antiaflatoxigenic, antioxidant activity,and favorable safety profile

The study reports antifungal and antiaflatoxigenic efficacy of chemically characterized Cymbopogon martinii essential oil (CMEO) against aflatoxigenic Aspergillus flavus causing infestation to stored herbal raw materials. In addition, the antioxidant activity and safety profile of CMEO were also assessed to recommend it as ideal preservative for stored herbal raw materials. The GC–MS of CMEO showed nerol as the major component (79.91%). CMEO inhibited growth and aflatoxin secretion of A. flavus LHPA₉ at 0.5 and 0.4 μl/ml respectively, showing better efficacy over synthetic antimicrobial Propineb 70. It also exhibited broad fungitoxic spectrum against fungi causing postharvest deterioration of herbal raw materials. The TEM analysis of CMEO-treated fungal cells showed disruption of plasma-membrane and deformed cell organelles. The EO also caused inhibition of ergosterol content emphasizing plasma membrane as active site during antimicrobial action. CMEO also exhibited pronounced antioxidant activity (IC₅₀ = 49 μl/ml) better than nerol, the major component of CMEO. The LD₅₀ of CMEO, determined through oral administration on mice, was calculated as 2569.16 mg/kg body weight indicating its favorable safety profile as preservative. CMEO may thus be recommended as postharvest preservative in enhancement of shelf life of herbal raw materials against storage fungi, mycotoxins, and oxidative deterioration.     

Screening of antifungal activity of various plant leaves extracts from Indian plants

The present study was designated to evaluate the antifungal activity and to root out the antifungal plant leaf extracts from this Indian folk-flore. The in vitro antifungal assay was performed by agar diffusion test and minimum inhibitory concentration (MIC) for hexane, ethyl acetate, methanol and distilled water plant leaf extracts. Extraction of 17 different plant leaves was carried out in different solvents such as hexane, ethyl acetate, methanol and distilled water. Among them extractive yield of methanol was maximum than the rest of the three solvents. These extracts were screened for their antifungal activity against nine different fungi. Among these ethyl acetate extracts of Adhatoda vasica, Ocimum sanctum and Holoptelea integrifolia exhibited maximum antifungal activity against Alternaria sp., Aspergillus parasi, Aspergillus nidulans, Trichoderma harzianum and Aspergillus flavus with MIC of 80, 40 and 20 ppm against Aspergillus nidulans and Alternaria sp. Ethyl acetate extracts showed promising antifungal activity against Adhatoda vasica, Ocimum sanctum and Holoptelea integrifolia against Aspergillus nidulans, and Alternaria sp. might be applicable as fungicide against fungal plants disease.     

Assessing essential oil components as plant-based preservatives against fungi that deteriorate herbal raw materials

This study assesses the antifungal efficacy of 14 essential oil (EO) components and some of their combinations as inhibitory to the growth of the aflatoxigenic fungus Aspergillus flavus LHPA₉ isolated from biodeteriorating Asparagus racemosus herbal raw materials. The aim was to determine whether they could be recommended as plant-based preservatives for enhancement of the shelf life of herbal raw materials. Thymol, eugenol, menthol, and their combinations were highly efficacious as their minimum inhibitory concentration (MIC) for inhibition of fungal growth as well as aflatoxin B₁ secretion was less than 1.0 μl ml⁻¹. Geranyl acetate, linalool, β-asarone, 1, 8-cineol, and E-citral were moderately antifungal as their MIC ranged between 1.0 and 5.0 μl ml⁻¹. During antioxidant activity 2, 2-diphenyl-1-picrylhydrazyl assay, thymol, eugenol, and β-caryophyllene showed strong radical scavenging activity, whereas β-asarone and p-cymene showed moderate activity. Some combinations of EO components showed synergism while others exhibited an additive or antagonism effect in their activity. The findings point to a recommendation that EO components are good alternatives to synthetic preservatives to prevent deterioration of stored herbal raw materials by fungal and aflatoxin contamination and free-radical oxidation.     

Biodeterioration of some herbal raw materials by storage fungi and aflatoxin and assessment of Cymbopogon flexuosus essential oil and its components as antifungal

Deterioration of raw materials of six medicinal plants viz. Terminalia arjuna, Acorus calamus, Rauvolfia serpentina, Holarrhena antidysenterica, Withania somnifera and Boerhaavia diffusa was examined. Some of the contaminated raw materials were found to be deteriorated by toxigenic strains of Aspergillus flavus and contain aflatoxin B₁ (41.0–95.4 μg kg⁻¹) which is above the permissible limit. Essential oil of Cymbopogon flexuosus and its components was found efficient in checking fungal growth and aflatoxin production. C. flexuosus essential oil absolutely inhibited the growth of A. flavus and aflatoxin B₁ production at 1.3 μl ml⁻¹ and 1.0 μl ml⁻¹ respectively. The individual oil components were more efficacious than the Cymbopogon oil as such which emphasizes masking of their efficacy when combined together. Eugenol exhibited potent antifungal and aflatoxin inhibitory activity at 0.3 μl ml⁻¹ and 0.1 μl ml⁻¹ respectively. Eugenol was found superior over some prevalent synthetic antimicrobials and exhibited broad fungitoxic spectrum against some biodeteriorating moulds. Prospects of exploitation of the oil and its components as acceptable plant based antimicrobials in qualitative as well as quantitative control of biodeterioration of herbal raw materials have been discussed.     

In vitro biopesticide effect of alkaloids and flavonoids of some plants against Fusarium oxysporum

Alkaloids and flavonoids of three plants, namely Withania somnifera, Euphorbia hirta and Terminalia chebula, were tested for their antifungal potential against plant pathogenic fungi Fusarium oxysporum. The spore counting technique was followed for the antibiotic properties of the extracts tested at three different concentrations (2.5, 5 and 10?mg/ml). Results revealed that the bound flavonoid of root of W. somnifera and free flavonoids of stem bark and fruits of T. chebula totally inhibited spore germination of the fungi (100%). The range of minimum inhibitory concentration and minimum fungicidal concentration of extracts recorded was 0.039–0.625 and 0.039–1.25?mg/ml, respectively. Bound flavonoids of selected plants were more effective than free flavonoids and alkaloids. The study suggests that both alkaloids and flavonoids extracts of selected plants have a potential antifungal properties for the control of diseases of various crops.     

Toxigenic Aspergillus flavus and aflatoxins in Sri Lankan medicinal plant material

The fungal flora of 6 Asian medicinal plants, Aerva lanata (Linn.) Juss. Alyssicarpus vaginalis D.C., Tribulus terrestris Linn. Adhatoda vasica Nees., Centella asciatica (L.) Urb., Cardiospermum halicacabum Linn. was determined. After surface disinfection Aspergillus spp. were most frequently observed. Aspergillus flavus, isolated from Alyssicarpus vaginalis and Aerva lanata produced aflatoxins in culture. Aflatoxin B₁ was also detected in a sample of Aerra lanata at a level of 0.5 g/g. Plant material destined for medicinal use should be stored carefully prior to its use to prevent growth of naturally occurring toxigenic mold fungi.     

Reversal of cadmium chloride-induced oxidative stress and genotoxicity by Adhatoda vasica extract in Swiss albino mice

Adhatoda vasica Nees (Acanthaceae) that is used by Ayurvedic physicians possesses some established medicinal properties. Environmental and occupational exposure with cadmium affects the renal system adversely. Cadmium is an established genotoxic agent. In the present study, we evaluated the antioxidant and anticlastogenic efficacy of A. vasica against cadmium chloride (CdCl₂)-induced renal oxidative stress and genotoxicity in Swiss albino mice. A single intraperitoneal dose of CdCl₂ (5 mg/kg BW) resulted in significant (p<0.001) increase in chromosomal aberration and micronuclei formation. Oral administration of A. vasica at two doses (50 and 100 mg/kg BW) for seven consecutive days showed significant (p<0.001) suppression of mutagenic effects of CdCl₂ in plant-pretreated groups. To study the mechanism by which A. vasica exerts its antimutagenic potential, enzymes involved in metabolism and detoxification were also estimated. Cadmium intoxication altered the antioxidant levels and enhanced MDA formation significantly (p<0.001). A. vasica showed significant (p<0.001) recovery in antioxidant status, viz., GSH content, its dependent enzymes, and catalase activity. Prophylactic pretreatment of A. vasica extract in cadmium-intoxicated mice showed marked (p<0.001) inhibition of lipid peroxidation (LPO) and xanthine oxidase (XO) activity. The present findings support that antimutagenic efficacy of A. vasica can be attributed to its restoring effects on antioxidant status and suppression of MDA level formation.     

Antifeedant activity and toxicity of two alkaloids from Adhatoda vasica Nees leaves against diamondback moth Plutella xylostella (Linn.) (Lepidoptera: Plutellidae) larvae

Two natural alkaloids viz., Vasicine acetate and 2-Acetyl benzylamine, isolated from Adhatoda vasica leaves, showed antifeedant, larvicidal and moult inhibiting properties against diamondback moth Plutella xylostella in laboratory experiments. Maximum antifeedant activity of 98.5% was recorded at 1000 ppm concentration of Vasicine acetate treatment, whereas as 2-Acetyl benzyl amine recorded only 71.4% antifeedant activity at 1000 ppm concentration. Azadirachtin treatment presented 82% antifeedant activity at the highest concentration (1000 ppm). Both the active compounds of A. vasica showed lethal toxicity on larvae and pupae. The highest larvicidal and pupicidal activities were recorded in 2-Acetyl benzylamine treatment at 125 ppm concentration. The two A. vasica compounds also affected the normal growth and development and moulting process of P. xylostella. Final moulting of larvae into pupae was disrupted by the treatments, which resulted in larval–pupal intermediates and abnormal pupae. Treatments also produced small-size pupae and malformed adults with poorly developed wings.     

Diversity of fungal endophytes in some medicinal plants of Himachal Pradesh,India

Fungal endophytes were isolated from surface sterilised leaf segments of five medicinal plants collected from Mandi district, Himachal Pradesh, India. A total of 373 fungal strains belonging to 15 fungal genera and 18 species, Aspergillus niger, A. flavus, A. clavatus, A. variecolor, Penicillium chrsogenum, Alternaria alternata, Curvularia lunata, Haplosporium sp., Phoma sp., Nigrospora sp., Colletotrichum sp., Cladosporium sp., Stemphylium sp., Fusarium sp., Geotrichum sp., Phomopsis sp., Trichoderma sp., Rhizopus sp. and some sterile mycelium were isolated from all the plants. The relative frequency, isolation rate and colonisation rates of endophytes were used to study the endophytic diversity. The results showed that the highest colonisation rate (93.05%) was observed in Adhathoda vasica, while it was 91.66% in Ocimum sanctum, 85% in Viola odorata, 82.81% Cannabis sativa and lowest (61.11%) in Withania somnifera. Moreover, reading the richness and diversity of the endophytic fungi, the highest was obtained for O. sanctum, W. somnifera and C. sativa having eight species each, while lowest (6 and 4) was obtained from A. vasica and V. odorata, respectively. As the role of endophytic organisms in defensive mechanisms of plants is now well established, the present study is an important step to find new and interesting endophytes among the medicinal plants.     

Quinoline Based Monocarbonyl Curcumin Analogs as Potential Antifungal and Antioxidant Agents: Synthesis,Bioevaluation and Molecular Docking Study

In search for new fungicidal and free radical scavenging agents, we synthesized a focused library of 2‐chloroquinoline based monocarbonyl analogs of curcumin (MACs). The synthesized MACs were evaluated for in vitro antifungal and antioxidant activity. The antifungal activity was evaluated against five different fungal strains such as Candida albicans, Fusarium oxysporum, Aspergillus flavus, Aspergillus niger, and Cryptococcus neoformans, respectively. Most of the synthesized MACs displayed promising antifungal activity compared to the standard drug Miconazole. Furthermore, molecular docking study on a crucial fungal enzyme sterol 14α‐demethylase (CYP51) could provide insight into the plausible mechanism of antifungal activity. MACs were also screened for in vitro radical scavenging activity using butylated hydroxytoluene (BHT) as a standard. Almost all MACs exhibited better antioxidant activity compared to BHT.     

Therapeutic Potential of Selected Medicinal Plant Extracts against Multi-Drug Resistant Salmonella enterica serovar Typhi

Salmonella enterica serovar Typhi is Gram negative, rod shaped, facultative anaerobic bacterium, belongs to enterobacteriaceae family that causes typhoid fever in humans. This bacterium has become a super bug due to acquisition of multi drug resistance. Bacteria is transmitted through food and water contaminated with human feaces. Present study reports the screening of Adhatoda vasica, Amaranthus hybridus and Aloe barbadensis and their evaluation against multi-drug resistant Salmonella enterica serovar Typhi. Qualitative analysis of ten phytochemicals was conducted using chemical method and Gas Chromatography-Mass Spectrometry (GCMS). Antibacterial activity of plants was carried out by agar well diffusion method on Mueller Hinton agar. Total tannins, total alkaloids and total flavonoids of different parts of three plants were estimated through spectrophotometer. Total tannins content in different parts of plants was present in the given order Amaranthus hybridus leaf > Aloe barbadensis leaf > Adhatoda vasica leaf > Adhatoda vasica flower > Adhatoda vasica stem. Whereas, the order of total flavonoid concentration was Amaranthus hybridus leaf > Aloe barbadensis leaf > Adhatoda vasica leaf > Amaranthus hybridus seed. Total alkaloids have order, Adhatoda vasica leaf > Amaranthus hybridus leaf > Adhatoda vasica flower > Amaranthus hybridus seed > Aloe barbadensis leaf. Results of phytochemical analysis suggested that plants have strong profile of antioxidants, total phenolic contents and various enzymes proposing them best alternate to cure bacterial infections. GC-MS analysis further confirmed stronger phytochemical profile that can be utilized as antagonists to Salmonella enterica serovar Typhi.     

Insecticidal effect of plant extracts on two termite species

The insecticidal contact activity of two desert plant extracts, Withania somnifera and Solanum incanum (Tubiflora: Solanaceae) was tested against the workers of the two species, Amitermes messinae and Microtermes najdensis (Isoptera: Termitidae). The insects were exposed to the plant extracts on Petri dishes (10 cm diameter) for 30 min. Mortality was calculated after 24 h. Crude extract of S. incanum leaves was more toxic to the two species of termites than W. somnifera.     

Gene targets for fungal and mycotoxin control

It was initially shown that gallic acid, from hydrolysable tannins in the pelliele of walnut kernels, dramatically inhibits biosynthesis of aflatoxin byAspergillus flavus. The mechanism of this inhibition was found to take place upstream from the gene cluster, including the regulatory gene,aflR, involved in aflatoxin biosynthesis. Additional research using other antioxidant phenolics showed similar antiaflatoxigenic activity to gallic acid. Treatment ofA. flavus withtert-butyl hydroperoxide resulted in an almost doubling of aflatoxin biosynthesis compared to untreated samples. Thus, antioxidative response systems are potentially useful molecular targets for control ofA. flavus. A high throughput screening system was developed using yeast,Saccharomyces cerevisiae, as a model fungus. This screening provided an avenue to quickly identify fungal genes that were vulnerable to treatment by phenolic compounds. The assay also provided a means to quickly assess effects of combinations of phenolics and certain fungicides affecting mitochondrial respiration. For example, theS. cerevisiae sod2† mutant was highly sensitive to treatment by certain phenolics and strobilurins/antimycin A, fungicides which inhibit complex III of the mitochondrial respiratory chain. Verification of stress to this system in the target fungus,A. flavus, was shown through complementation analysis, wherein the mitochondrial superoxide dismutase (Mn-SOD) gene (sodA) ofA. flavus in the ortholog mutant,sod2†, ofS. cerevisiae, relieved phenolic-induced stress. Mitochondrial antioxidative stress systems play an important role in fungal response to antifungals. Combined treatment of fungi with phenolics and inhibitors of mitochondrial respiration can effectively suppress growth ofA. flavus in a synergistic fashion.     

Recent advances in elucidating the biological properties of Withania somnifera and its potential role in health benefits

Withania somnifera (L.) Dunal (Solanaceae), also known as ashwagandha, is an important medicinal plant that is widely used as a home remedy for several diseases in the Indian subcontinent and other parts of the world. W. somnifera is a dietary supplement composed of various nutrients, polyphenols and alkaloids that have free radical scavenging capacity, as well as other chemical constituents that possess anti-inflammatory, antitumor, anti-stress, antioxidant, immunomodulatory, and rejuvenating properties. The mechanism of action for these properties are not fully understood. W. somnifera also appears to influence the endocrine, cardiopulmonary and central nervous systems. Toxicity studies reveal that W. somnifera can be used without side effects. The findings presented in this review are very encouraging and indicate that this herb should be studied more extensively to confirm these results and to reveal other potential therapeutic effects.     

Antioxidant and Antimicrobial Activity in Some Indian Herbal Plants: Protective Effect against Free Radical Mediated DNA Damage

Indian herbal plant species Lantana indica, Adhatoda vasica, Pandanus furcatus, Tylophora indica and Centella asiatica, traditionally used in ethno medicines to treat common infections and various disorders, have been studied for their antimicrobial and antioxidant activity. The methanolic extracts of the plant leaves exhibited significant and dose-dependent antioxidant activities in DPPH radical scavenging, ferric ion reducing and phosphomolybdate assays. These leaf extracts showed antimicrobial activity against selected Gram +ve and Gram ?ve bacterial strains. A. vasica and L. indica extracts possessed maximum antioxidant and antimicrobial activity, respectively. The activities could be correlated to phenolics and flavonoid content of the leaf extracts which ranged from 30.25 to 91.98 mg GAE g^?1 dw leaf extract and 2.67 to 96.45 mg RE g^?1 dw leaf extract respectively. The aqueous extracts of plant leaves significantly protected the DNA damage against the oxidative damage caused by hydroxyl radicals.     

Genetic structuring in wild populations of two important medicinal plant species as inferred from AFLP markers

Systematic analysis of germplasm diversity and genetic relationship among cultivars is critical for development of appropriate conservation and breeding strategies. This approach has been applied to gain an insight about the molecular variance that exists in wild population of two important medicinal plant species of India that have a long history of therapeutic usage in herbal medicine. Adhatoda vasica and Andrographis paniculata, members of the family Acanthaceae, have wide geographical and climatic distribution across India suggesting a large amount of genetic diversity available for resource management and breeding programs. In this study we have assessed the genetic diversity of both these species distributed in five varied geo-environmental regions, using Amplified Fragment Length Polymorphism (AFLP) fingerprinting with selected primer combinations and statistical analysis. Cluster analysis and analysis of molecular variance also suggested a very high genetic variation. Detailed analyses of the results predict that the genetic variation found in A. vasica was more discrete that reflected strongly in the populations studied, whereas the genetic variation in A. paniculata was relatively uniform. Considering significantly large sample size and distinctive characteristics of the selected populations, this work contributes valuable insights that can be used to engineer conservation and utilization strategies for these species.     

Pseudomonas aeruginosa WS-1 for biological control of leaf blight disease of Withania somnifera

Withania somnifera (L.) Dunal, also known Indian ginseng is one of the most widespread tranquillizers tranquillisers used for the treatment of nervous disorders, intestinal infection, leprosy, and cancer; it also suffers a leaf blight disease caused by the fungus Alternaria dianthicola in various districts of South Bengal, India: Pseudomonas aeruginosa strain WS-1 isolated from the rhizosphere, showed both in vitro and in vivo antagonistic activity against the pathogen. The antifungal activity of the isolate has been found to be linked to theproduction of a siderophore, volatile substances (hydrocyanic acid), proteases and chitinases. Foliar application of a talc talc-based formulation of P. aeruginosa strain WS-1 to field grown W. somnifera reduced disease severity by 80% compared to non-treated control.     

Nematode inhibiting organic materials and a strain of Trichoderma harzianum effectively manages Meloidogyne incognita in Withania somnifera fields

The usefulness of Trichoderma harzianum was tested along with farmyard manure, cow urine, neem oil seed cake, and vermicompost separately and in combination to manage Meloidogyne incognita in Withania somnifera. A treatment combination of nematode inhibitory vermicompost and T. harzianum was found to be most effective against M. incognita.     

Molecular identification of three isolates of Jatropha mosaic India virus associated with mosaic disease of Withania somnifera in India

The association of begomovirus with mosaic disease of Withania somnifera was detected at three locations in India by PCR using begomovirus-specific degenerate primers. The resulting amplicons of ～1.2 kb from three locations (Aligarh, Lucknow and Hindaun City) were sequenced. The begomovirus isolates of three locations shared 96–97% identities among them and 91% identities with Jatropha mosaic India virus (JMIV). Based on highest sequence identities and close phylogenetic relationships with JMIV, these begomovirus isolates associated with mosaic disease of W. somnifera were identified as isolates of JMIV.     

Stabilization of Membrane Bound Enzyme Profiles and Lipid Peroxidation by Withania Somnifera Along with Paclitaxel on Benzo(a)pyrene Induced Experimental Lung Cancer

The present study was aimed to evaluate the therapeutic effects of Withania somnifera along with paclitaxel on lung tumor induced by benzo(a)pyrene in male Swiss albino mice. The levels of ATPase enzymes and lipid peroxidation were evaluated in lung cancer bearing mice, in erythrocyte membrane and tissues. The extent of peroxidation was estimated by measuring the thiobarbituric acid-reactive substances. Simultaneously the activities of different ATPases (Na⁺/K⁺-ATPases, Mg²⁺-ATPases and Ca²⁺-ATPases) were determined. The alterations of these enzyme activities in membrane and tissues were indicative of the tumor formation caused by benzo(a)pyrene (50 mg/kg body weight, orally) in cancer bearing animals. The activities of these enzymes were reversed to near normal control values in animals treated with Withania somnifera (400 mg/kg b.wt, orally) along with paclitaxel (33 mg/kg b.wt, i.p). Treatment with Withania somnifera along with paclitaxel altered these damage mediated through free radicals, and the treatment displays the protective role of these drugs by inhibiting free radical mediated cellular damages. Over, based on the data providing a correlation Withania somnifera along with paclitaxel provide stabilization of membrane bound enzyme profiles and decreased lipid peroxidation against benzo(a)pyrene induced lung cancer in mice.