Browsing by Author "Ghosh, Chandra"

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Open Access
Acaricidal and Ovicidal Effects of Vitex negundo, Against Oligonychus coffeae, A Common Pest Found in Tea Gardens of North Bengal, India
(University of North Bengal, 2023) Ghosh, Sandipan; Sen, Gargi; Ghosh, Chandra; Sen, Arnab
Tea, a widely consumed and economical beverage across 65 nations, confronts substantial challenges from pests, notably the destructive Red spider mites, which pose significant hurdles for the industry due to their resilient nature and severe impact. Chemical pesticides, while effective against pests in tea production, degrade tea quality, prompting exploration into natural alternatives like floral diversity for pest control. A study in North Bengal, India, aims to the pest-controlling abilities of common weed found in tea gardens in the Terai and Dooars regions.The aqueous extracts of Vitex negundo L. as biocide employed in this study demonstrated substantial acaricidal and oviposition deterrent action against the tea Red Spider Mite Oligonychus coffeae after 48 hours of application. In the future, this aqueous extract could prove to be a fairly priced and efficient acaricide.
Open Access
Biology of tea garden weeds in Darjeeling district of West Bengal(India)
(University of North Bengal, 2006) Ghosh, Chandra; Das, A P
Open Access
Ethno-medicinal and molecular profiling of fermented beverages consumed by different tribes in North Bengal, India
(University of North Bengal, 2024) Bhattacharjee, Soumita; Sen, Arnab; Ghosh, Chandra
The widespread adoption of preserving food through natural fermentation has ancient origins, primarily stemming from the ancestral wisdom of Tribal communities. Ethnic foods and beverages are described as culinary offerings that have their roots in the heritage and culture of a particular ethnic group, drawing upon their understanding of locally sourced plant and animal ingredients. India houses a multitude of tribal communities spread across diverse geographical regions. Among these communities, alcoholic beverages hold considerable popularity among the tribal population. As a preservation technique, the ancestral practice of natural fermentation has endured through the indigenous knowledge transmitted by ancestors within these tribes. The mildly alcoholic, sweet-flavoured beverages are regarded more as food than alcoholic drinks due to their highcalorie content, vitamins, and beneficial lactic acid bacteria and yeast. Traditionally prepared alcoholic beverages are cereals such as rice, wheat, maize, or ragi, which have been the substrate of choice for their preparation, depending on the habitat of the tribal population. For generations, alcoholic beverages have been consumed at diverse cultural, social, and religious events. Most fermented drinks predominantly use cereals as a base, incorporating many plants and fruits as the primary raw materials. This combination contributes to a distinct and unique taste in the beverage. Numerous traditional ethnic practices have been ignored, resulting in insufficient documentation for scientific analysis. Therefore, the present investigation was conducted to evaluate the appropriate scientific examination of select tribal beverages in North Bengal, India. Initially, various areas inhabited by tribal communities were selected to gather their respective traditional beverages, used plant parts and the starter culture. The initial screening was based on the alcohol content of the beverages. Eu, a millet-based drink utilized by the Toto tribe in North Bengal, Chokot, a ricebased drink consumed by the Rabha tribe in North Bengal, Harchur raksi, and Timboor raksi, traditional medicinal plant-based drinks used by the tribal community in the highaltitude region in Darjeeling Himalaya, and Haria, a rice-based drink consumed by the Orao and Santal communities in North Bengal, were selected for further study. The injection of starter cultures, serving as the source of ethnic microbiota to induce the fermentation process, was also included in the present study. In vitro, the antioxidant study was also conducted to evaluate the most potent among those, as mentioned earlier, low-alcoholic ethnic drinks. The study results show that Eu is the most potent beverage among the other tribal drinks. The Harchur raksi (HR) is a lesserknown beverage consumed by the indigenous people residing in the high -altitude regions of the entire Himalayan range. HR is unique in its traditional processing method, an indigenous knowledge held by the Darjeeling-Himalayan tribal community. This knowledge should be meticulously documented to preserve its uniqueness. Although HR is considered an anti-inflammatory brew with various ethnomedicinal claims by the local inhabitants, there has been no scientific evaluation thus far. A comprehensive survey was conducted across the Darjeeling Himalayan region to unearth the ethnobotanical knowledge related to HR. HR was identified and collected in collaboration with a local expert. This work aims to assess the physical, biochemical, and metabolite profiling of HR using different biochemical tests and Gas Chromatography–Mass Spectrometry (GC–MS) experiments. To get a deeper understanding of the medicinal properties of HR, in silico molecular docking studies were conducted. The analysis revealed that HR, with a notably low alcohol content (around 6–8%), exhibits high antioxidant activity. GC–MS analysis of the brew identified 27 bioactive compounds, which were further subjected to bioinformatics analysis. Molecular docking analysis demonstrated the inhibitory activity of most of these compounds against oxidative stress, inflammation, and specific potent viral proteins related to their pathogenicity. Timbur raksi is a distilled fermented alcoholic beverage from the highaltitude region of Darjeeling Himalaya. The methanolic extract of the sample exhibited 60% inhibition at a higher concentration (200μg/ml). The GC-MS evaluation of the sample revealed the presence of 43 bioactive compounds, which have potential applications as scavengers for reactive oxygen species, anti-inflammatory agents, and anticancer compounds. 'Choko'/'Chokot' is a rice-based beverage consumed by the ethnic tribal community 'Rabha' in North Bengal and Assam, India. While rice is the main ingredient in this fermented product, introducing the starter culture, popularly known as 'Bakhor or phap,' brings variation to its composition. 'Choko'/'Chokot' constitutes a significant portion of the daily caloric intake for the Rabha tribe. Metabolite profiling was examined through GC-MS analysis. Additionally, the Metagenomic analysis was employed to assess the total microbial load of the starter culture (Bakhor). Reverse ecology analysis delved into the interaction between the microbes present in the brew and humans. The results indicated that the compounds in this beverage mostly exhibit antimicrobial and antifungal effects despite its relatively higher alcohol content than other tribal ethnic drinks. The metagenomic analysis identified several dominant bacterial genera, including Bacillus, Arthrobacter, Lactobacillus, Ilyobacter, Clostridium, and Lactococcus. Haria is a fermented rice beverage crafted using a starter culture (Ranu dabai) to boiled rice grains. It is a casual drink in daily life and is also utilized to alleviate ailments such as fever, headache, and nausea. Including herbal plants in the starter culture enhances the beverage, providing it with beneficial organoleptic and therapeutic properties. While extensive research has been conducted on Haria, we have not included Haria in our analysis. However, our study does encompass an examination of the plants used in the starter culture of Haria, an area where comprehensive research still needs to be done. The plant-derived phytocompounds demonstrated significant antioxidant activity, suggesting their capacity to reduce reactive oxygen species (ROS) and reactive nitrogen species (RNS) generated during oxidative stress. Consuming the beverage may help overcome the growth of cancerous cells and slow the ageing process. Additionally, the herbal plants exhibit active antimicrobial properties, indicating a therapeutic role in inhibiting the growth of humanpathogenic bacteria and protecting the body from severe infections. "Eu" is a traditional mild alcoholic beverage made from millet and consumed by the Toto tribe in West Bengal. The preparation of Eu involves millet fermentation with the locally cultivated starter culture known as "Moaa." Ethnobotanical data and samples were collected through semi-structured interviews. Qualitative assays, such as acute toxicity, antioxidant analysis, gas chromatography-mass spectrometry (GC-MS), in vitro anti-inflammatory assay, molecular docking, and physiochemical assessments (pH and alcohol content), were conducted. The findings indicate that Eu has a low alcohol content (approximately 1-3%) and a high antioxidant capacity. GCMS analysis identified thirteen bioactive compounds. The starter culture employed in this brew comprises a diverse microflora. Identifying these microbes will enhance our comprehension of the brew and allow us to quantify its effects on the human system postconsumption. Leveraging advancements in Illumina sequencing technology, meta-profiling of the 16S rRNA (V3–V4 region) has become a valuable resource for scrutinizing the microbiome of various samples. We have utilized this tool to investigate the microbiome population of Eu. The microbial diversity found in the brew primarily consisted of probiotic and fermenting bacteria. Nutrient profiling of Eu assessed the levels of protein, carbohydrates, free amino acids, and free fatty acids. The nutritional content in the brew likely supports the growth of probiotic microflora. Reverse ecology-based network analysis unveiled substantial complementary interactions between humans and the microflora in the Eu. GC–MS analysis identified thirteen potent compounds in Eu, and an extensive network pharmacological study on these compounds revealed the anticancer properties of Eu, particularly against gastrointestinal malignancies. This was achieved by reducing the proliferation of malignant cells and forming pro-inflammatory cytokines. The probiotic microflora and the Eukaryotic Yeast also play a crucial role in fermentation. Several yeast cells were isolated from the starter culture, and from the isolated cultures based on biochemical screening, three strains were selected for identification. Molecular phylogenetic analysis based on ITS region (ITS1 and ITS4) sequencing of these three yeast isolates showing similarity with Saccharomyces cerevisiae. The MTT assay against the ACHN human renal adenocarcinoma cell line determined the cytotoxicity of Eu. The brew showed no cytotoxic effect. Whole metagenomic sequencing, or WMS, is particularly valuable in studying complex microbial ecosystems, where diverse microbial communities coexist. Whole metagenomic sequencing was done on the starter culture of Eu; the result showed .42% of Archaea, 60.80% of Bacteria, 22.84% of fungi, 11.95% of protozoa and 2.95% of Viruses within the sample. In vivo, acute and sub-acute oral administration toxicity study was conducted to show the efficacy of the drink Eu on a rat model. In the acute toxicity study, female and male Wistar rats received oral administrations of Eu of doses 250 and 500 mg/kg over 28 days following OECD Guidelines 425. In the sub-acute study, no significant reduction or gain of weight was observed when compared with the control group. The haematological and histopathological study also showed no significant alteration of the parameters when compared with the control. The spleen weight of both males and females was changed slightly compared to the standard, but this change is not dose-dependent. The result of sub-acute toxicity showed that an adequate amount of the drink.
Open Access
Ethnobotanical studies in India with notes on Terai-Duars and Hills of Darjiling and Sikkim
(University of North Bengal, 2007-03) Das, A. P.; Ghosh, Chandra; Sarkar, Ajita; Biswas, Rajib
The very survivability of man is greatly associated with plants since his origin. Plants are responsible for the supply of Man's oxygen, food, medicine, fibre, shelter and what not! Also the relationship between man and environment in general has never been static and is changing continuously. But this is not the case with tribal/ aboriginal communities the world over. The life, culture and traditions of these communities have remained almost undisturbed and static for hundreds of years. They are the living archaeological museums of ancient traditions and cultural heritage of a nation.
Open Access
Plant wealth of Darjiling and Sikkim Himalayas vis-à-vis conservation
(University of North Bengal, 2022-03) Das, AP; Ghosh, Chandra
The richness of the flora of Darjiling Hills along with Sikkim and Nepal parts of the Eastern Himalaya is well known and that has attracted plant lovers, explorers and hunters almost equally for the last three centuries or so. The processes of evolution worked in this part of the Himalayas almost in an undisturbed condition for millions of years assisted by much varied but extremely favourable climatic conditions and has produced innumerable new species, a good proportion of which are still endemic to the region. The vegetation structure and the flora in different parts of this region have developed as per the local climatic make-up. So, when almost tropical vegetation is found on outer low altitude areas, it is sub-alpine to alpine to arctic in high altitude areas especially above 3000 m. Terai and Duars are located at the feet of the hills are maintaining a contiguous rich vegetation. The vegetation scenario in this region is changing very fast during last three or four decades mostly due to anthropogenic activities. Extension of civilisation along with the population explosion lead to the increase in forest extraction, rate of modification of floristic composition, pollution content, soil erosion, plant introduction, clearing of natural vegetation etc. There is evidence that the force of evolution is still active here but the lack of proper corridor (along with other factors mentioned above) for plant migration will certainly cause the weakening of numerous local species and the rate of extinction of species will increase in a logarithmic scale. Like any other part of this planet here also it appears to be one nearly impossible task to save the local biodiversity. Just the declaration of some Protected Areas is not enough. Activities through ecotourism are also affecting the conservation practices. Unless we succeed to conserve the natural vegetation on this planet the entire biosphere will be dead within next 100 years.
Open Access
Studies on the selected tea garden weeds for the promotion of tea plant health
(University of North Bengal, 2024) Ghosh, Sandipan; Sen, Arnab; Ghosh, Chandra
Tea, cherished worldwide as a beverage of choice, holds a dominant position in India's agricultural landscape, representing 75% of the country's tea production. The North East region of India holds immense importance, making a substantial contribution of approximately 75% to the overall output. However, despite its paramount importance, tea production faces numerous challenges, chief among them being pest attacks. These attacks pose a significant threat, often leading to substantial losses that can range from 30% to 50%. Among the array of pests, the Red Spider Mite (RSM) poses a significant threat, characterized by a short life cycle and prolific reproductive capacity. In North East India, the economic threshold level for RSM is identified at 5 mites per leaf. The persistent use of conventional pesticides, coupled with the mite's rapid life cycle, has fostered considerable pesticide tolerance, leading to recurrent and challenging resurgences, thereby impacting the Indian tea trade. The tea plant is susceptible to diverse pests, including tea mosquito bugs, red slugs, red spider mites, thrips, jassids, etc. Among these, red spider mites and tea mosquito bugs stand out as predominant pests in the region, causing substantial crop losses in the tea industry annually. The association of Oligonychus coffeae with tea dates back to the inception of tea production in Assam, North East India, in 1868. While Nietner initially discovered O. coffeae on coffee plants (Coffea arabica) in Sri Lanka in 1861, it was Wood -Mason who, in 1884, designated it as a new species, Tetranychus bioculatus. However, Pritchard and Baker's 1955 studied on the family Tetranychidae prompted a revaluation, leading to the recognition of T. bioculatus as a synonym of the coffee mite, eventually placing it under the name Oligonychus. According to early data, the red spider mite, Oligonychus coffeae Nietner, (Acarina: Tetranychidae), is one of the most significant pests of Indian tea, and causing up to 35–40% of the crop to be lost. Red spider mites and tea mosquito bugs are seasonal pests. The former occurs during the summer months and the latter during rainy winter. RSM is a polyphagous pest that feeds on coffee, rubber, indigo, grape, cashew nut, citrus, mango, Camellia, camphor, mulberry, oil palm, and many other tropical plants. It normally infests the upper surface of mature tea leaves, feeds along the midrib and veins, and gradually spreads to the entire surface of the leaf, thereby changing the color of the leaf to ruddy bronze. Larvae, nymphs, and adult mites wreak havoc on the tea plant by feeding on the sap of the leaves and sporadically on the petioles. In severe infestation, it damages the younger and older leaves and ultimately leads to defoliation and debilitation of the tea bush causing a crop loss of 14–18%. In South India, the economic threshold level (ETL) of RSM in tea is reportedly 4 mites per leaf. and 2–3 mites/cm2 in North EastIndia. However, ETLs vary from area to region and even from field to field due to crop phenology, the cost of pesticides and manpower, weather patterns, etc. The RSM lives under the cover of a silken web spun on the leaf surface as protection against inclement weather. Leaf temperature and light penetration within tea bushes also influence mite distribution; O. coffeae prefers the middle zone of the bush (30 cm below the plucking surface) because of optimum temperatures associated with plant shading. The temperature in the upper zone of the tea plant may reach 40– 45 0C yet shading can bring down the temperature of the middle tier of a bush to ambient levels of 30–32 0C. Tea plantations use synthetic pesticides to manage pests, but researchers need to explore plants' bio pesticidal properties for environmental problems. Native plant materials like oils, extracts, and secondary metabolites protect against pests and illnesses. Plant-based preparations, including powders, solvent extracts, essential oils, and insecticidal properties, are also used as biopesticides. Botanicals play a vital role in organic tea production by effectively controlling pests such as red spider mites and keeping their population below the Economic Threshold Level (ETL). Consistent use of plant extracts from the same species mitigates herbivore responses and minimizes the risk of pest resistance development. Numerous studies from previous literature affirm that plant materials are abundantly accessible within local regions. The utilization of crude or raw plant extracts, containing a diverse amalgamation of bioactive components, emerges as a straightforward and economically feasible solution. This approach, exemplified by the utilization of aqueous extracts derived from various indigenous plants in India, underscores the practicality and cost effectiveness of harnessing natural resources for various applications. Plant based remedies for the red spider mite have included Clerodendron infortunatum L., Acorus calamus L., Aegl e marmel os (L.) C orrêa, Xanthium strumarium L., Terminalia chebula Retz., Duranta repens L., and neem kernel. The selection of plants should not limit the available plants to guarantee a wide range of protectants, and ongoing research into more potential plants is encouraged. It is significantly more important to carry out multiple bioassays when evaluating botanical pesticides. So objective of our study is the survey and documentation and characterization of plants used in preparing bio formulation for managing the pest. In different tea estates of tarai and dooars region and tea research institute start to introduce some cultural practices in combating tea pest using some locally available weed plants. With such information in together, we chose ten weed plants based on the results of the survey data. Then collect those plant and prepare a bioformulation. We also prepared individual plant aqueous extracts to know which plant is more effective than a formulation and found Clerodendron infortunatum L., Artemisia vulgaris L., and Justicia adhatoda L. confer better results than other plants when applied to a red spider mite in a laboratory condition. Next, we formulate bioformulations using locally sourced plants, drawing upon both existing literature and the traditional knowledge of tea garden inhabitants. Initially, to evaluate the effectiveness of these bioformulations, greenhouse experiments were conducted, administering them at different dosages to infected samples. Following the acquisition of promising outcomes, we advanced to field trial experiments carried out in two distinct tea estates, situated in both the Terai and Dooars regions. As part of our ongoing exploration into the composition of the bioformulation, we embarked on comprehensive GCMS analysis, revealing the presence of specific compounds within its formulation. To gain deeper insights into the potential impact on insect pests, particularly the two-spotted red spider mite (Tetranychus urticae), we selected relevant proteins from the PDB database. Employing molecular docking studies, we substantiated that the presence of these identified compounds in the bioformulation could be a contributing factor to the mortality of the insect pest. Additionally, our findings are in line with earlier literature studies that underscore the pesticidal activity linked to these compounds. In the metagenomic approach applied to the bioformulation, an intricate exploration of the microbial flora within the bioformulation was unveiled. Furthermore, the reverse ecology study lends support to the notion that there exists a robust interaction among the bacteria, influencing their impact on the pest population. Upon inflicting damage to the pest, the ensuing generation of reactive oxygen species (ROS) triggers the activation of antioxi dantenzymes. Our investigation involved the collection of leaves from both infected plants and those treated with the bioformulation, alongside a positive control. Subsequent analyses, including various enzymatic and nonenzymatic tests, revealed that our bioformulation contributes to the reduction and mitigation of biotic stress. Moreover, our bioformulation demonstrated a positive influence on the activity of Plant Growth-Promoting activity by inducing changes in soil physiochemical composition. This, in turn, resulted in improvements in plant height, leaf count, and flushes, showcasing the multifaceted benefits conferred by our bioformulation.