1. KAUTIR (Kerala Agricultural University Theses Information and Retrieval)
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Item Characterization of selected Centella asiatica genotypes using asiaticoside and gene-specific markers(Department of Plant Biotechnology, College of Agriculture , Vellayani, 2022-11-15) Jayath Gowri, J; Sabu , K KThe study entitled “Characterization of selected Centella asiatica genotypes using asiaticoside and gene-specific markers” was carried out at the Biotechnology and Bioinformatics Division of KSCSTE-JNTBGRI, Palode, during 2021-2022 with the objective to characterize six selected accessions of C. asiatica with respect to morphology, asiaticoside production, and gene expression profiling. Morphological characterization was done with the help of eight quantitative traits. The descriptive statistics of the recorded data were performed using Grapes 1.0.0 web application designed by KAU. Five of the eight traits exhibited significant variation among the six accessions. Leaf area, leaf breadth, leaf thickness, petiole length, and petiole diameter revealed significant variation (p<0.05). Quantification using reversed-phase HPLC estimated that CA449 has the highest content of both asiaticoside (ASD) and madecassoside (MSD). The lowest ASD content was found in CA379, while the lowest MSD content was found in CA459. The content of ASD ranged from 4.9- 8.8% per 100g dry weight and MSD ranged from 9.7- 15.3% per 100g dry weight among the six genotypes. Gene expression profiling using real-time PCR revealed that the genes involved in asiaticoside biosynthesis (BAS, SQS, and UGT) show the highest expression in CA449 and the lowest expression in CA379. To understand the statistical relationship between the variables used in the study, correlation analysis was performed with the help of Grapes 1.0.0 web application. ASD was highly positively correlated with leaf length, leaf breadth, leaf area, and petiole length. MSD was found to have a substantial positive correlation with petiole length. The positive correlation between secondary metabolites (ASD & MSD) and gene expression of its biosynthetic genes suggests that changes in phytochemical components could be attributable to genetic variances. The six genotypes have shown significant variation at phenotypic, phytochemical (ASD & MSD) and genetic levels. Best character performance was recorded in the accession CA449 with highest leaf area, leaf length, leaf breadth, petiole length, number of dentations per leaf, high ASD & MSD content and maximum expression of BAS, SQS, and UGT. To summarize, the findings offer an initial assessment of natural variation in selected genotypes of C. asiatica, laying the groundwork for future breeding purposes.Item Protocol development for gel stabilization and nutraceuticals in aloe vera (L.) Burm. f.(Department of Plantation Crops and Spices, College of Agriculture, Vellayani, 2021) Maheswari R S Nair; Sreekala, G SThe investigation entitled “Protocol development for gel stabilization and nutraceuticals in Aloe vera (L.) Burm. f.” was carried out in the Department of Plantation Crops and Spices, College of Agriculture, Vellayani during March 2016 to December 2019. The project envisaged formulation of a low cost stabilization technique for aloe gel using herbal extracts and aromatic oils and development of protocols for the preparation of dried latex and marketable nutraceuticals using aloe gel. The study was carried out as four experiments. The first experiment was to study the keeping quality and natural spoilage flora of fresh gel while the second experiment was for the standardization of curacao aloe (dried latex). The third experiment was on gel stabilization using herbal extracts and essential oils. Preparation of nutraceuticals from the stabilized liquidized aloe gel juice was the final experiment. The keeping quality and natural spoilage flora of fresh gel were assessed by subjecting the liquidized aloe gel juice to storage in glass bottles under ambient condition for seven days. The liqudized aloe gel juice was off white in colour for first three days of extraction with mild vegetative odour and got sedimented with foul smell from fourth day onwards. The liquidized aloe juice could not be stored for more than a day due to increased microbial population from the second day of storage. Preliminary trails conducted by pasteurizing the liquidized aloe gel juice at 65 0C and 15 psi pressure for 13 minutes followed by flash cooling registered no microbial population even after seven days of storage. The latex collected from aloe leaves was subjected to different methods of drying such as boiling followed by cooling, sun drying, shade drying and oven drying. Appearance, colour and aloin content (271.62 mg/ml) of dried latex was significantly higher for shade drying. Liquidized aloe gel juice was pasteurized and added with varying concentrations of three forms (aqueous, tincture, decoction) of herbal extracts and essential oils after adjusting the pH to 3.5 by adding 0.5 per cent of citric acid for gel stabilization. The treated samples were kept for a month and based on microbial population and minimum inhibitory concentration best treatment of each form was selected from preliminary trials for aloe gel stabilization. Gymnema sylvestre aqueous extract (1 ml), tincture (1 ml), decoction (2 ml), Centella asiatica aqueous extract (1 ml), tincture (2 ml), decoction (1 ml), Achyranthes aspera aqueous extract (2 ml), tincture (2 ml), decoction (1.50 ml), Tridax procumbens aqueous extract (2 ml), tincture (2 ml) , decoction (1 ml), Terminalia chebula aqueous extract (1 ml), tincture (1 ml), decoction (1 ml), Punica granatum aqueous extract (1 ml), tincture (2 ml), decoction (1 ml), green tea aqueous extract (2 ml), tincture (1 ml) and decotion (2 ml) and 1 ml each of sacred basil oil, lemon grass oil, cinnamon bark oil, clove oil and cardamom oil were selected and added to pH adjusted , pasteurized and liquidized aloe gel juice (25 ml) for gel stabilization. The gel stabilization was thus done using the selected twenty six treatments in a Completely Randomised Design replicated five times and compared with 0.08 per cent sodium benzoate as control and stored for six months. Appearance, colour and odour of all forms of the herbal extracts reduced on storage while those treatments with aromatic oils showed lesser percentage reduction in these parameters. Total solids, amylase and lipase activity decreased on storage. The amino acid content was the highest for liquidized aloe gel juice added with aqueous, tincture and decoction of Achyranthes aspera (0.08 ppm).Vitamin A and C were highest for treatment with green tea leaf aqueous extract which decreased subsequently on storage. An increase in microbial load was observed for all the treatments with herbal extracts from first month of storage. But addition of 1 ml clove oil resulted in stabilization of liquidized aloe gel juice which could be stored upto five months without microbial contamination or affecting the nutritive and sensory parameters. Nutraceuticals were prepared using stabilized liquidized aloe gel juice containing clove oil blended with lemon juice, orange juice and honey in proportions of 50 : 50, 75 : 25 and 90 : 10 followed by pasteurization, flash cooling and stored for 6 months. Appearance, colour and vitamin C were significantly higher for Lemon juice (50 ml) + Liquidized aloe gel juice (50 ml) + 2 ml clove oil while odour, taste, overall acceptability, pH, TSS, carbohydrates and calories were significantly superior for Honey (50 ml) + Liquidized aloe gel juice (50 ml) + 2 ml clove oil. Growth of microbes could be detected from third month of storage for all the treatments. Aloe health drink with honey in the ratio 50 : 50 added with clove oil were selected as the accepted drink which could be preserved for two months without microbial contamination. The preparation of aloe herbal powder by solar drying, air drying, oven drying or freeze drying resulted in a sticky product which could not be reconstituted with distilled water for quality comparison with fresh gel, thus warranting further investigation. The present study revealed that liquidized aloe gel juice pasteurized and mixed with clove oil (4 per cent) is a low cost stabilization method which can be taken as a base material for the preparation of health drink. The nutraceutical with liquidized and stabilized aloe gel juice mixed with equal proportion of honey and preserved with clove oil is a palatable drink having higher calories which could be stored for two months. The dried aloe latex a byproduct produced by shade drying is superior with high aloin content and can also be used for the development of marketable product.Item Development of functional est-ssr and analysis of genetic diversity in centella asiatica(Department of Plant Biotechnology, College of Agriculture, Vellayani, 2018) Arya Aravind; Sabu, K KCentella asiatica is a small trailing perennial herb and is the only species of Centella seen in India. Stem is green to greenish red colour and rooting at nodes. These connects plants each other. Petiole is long, smooth, green in colour. Leaves are palmately veined fleshy leaves. Plants are mainly found in marshy land of tropical and subtropical regions. Genetic diversity is that the total variety of genetic characteristics within the genetic makeup of a species. It plays a very important role within the survival and flexibility of a species and is important for a species to evolve. We aim to develop and use transcriptome based SSR molecular marker for analysis of genetic diversity in Centella asiatica in relation to the content of triterpenoids. To achieve that 129 Primers were designed from the transcriptome sequence obtained from NCBI. To validate the designed primers 15 primers were selected and used for genetic diversity analysis in 30 different Centella accessions collected from different regions of Tamil Nadu and Kerala. The genetic diversity analysis result grouped the accessions in to six group based on the genetic distance. Single accessions was randomly selected from each group to chemical analysis the asiaticoside content and additionally two phenotypic characters were also characterised in all 30 collected accessions. The result of genetic diversity analysis shows the less Nei heterozygosity (0.0433) between the studied accessions and the positive correlation (0.142) with the asiaticoside content. From the analysed phenotypic characters, number of leaves per node character shows the interesting positive correlation (0.291) with asiaticoside content than genetic diversity. This study gives the positive and initiative step to the genetic diversity and the asiaticoside content correlations. This will be helpful to find out the functional marker related to asiaticoside content which will be useful in MAS studies in future.Item Etiology of honey bee brood disease in Southern Kerala(Department of Agricultural Entomology, College of Agriculture, Vellayani, 2018) Jyothis, P Joseph; Amritha, V SItem Agrobactrium tumefaciens mediated genetic transformation in Kudangal (Centella asiatica L. Urban)(Department of Plant Biotechnology, College of Agriculture, Vellayani, 2006) Nanditha Krishnan, V; Soni, K B