Ortho-dihydroxy Phenols Research Articles

Assessment of pharmacological activities of specialized metabolites of Withania somnifera (L.)

Withania somnifera is a revered herb in the Indian medicinal system due to the presence of pharmacologically bioactive compounds. The roots and leaves of Ashwagandha contain various phytochemicals like phenols, flavonoids, quinones, steroids, etc. These phytochemicals are distributed among various tissues of this plant in varying concentrations. Since location and environmental factors (biotic and abiotic) play a key role in the biosynthesis of bioactive metabolites, the agro-climatic conditions are conducive to introducing and domesticating new exotic plant varieties with enhanced phytochemicals and withanolide contents. The present study focuses on the assessment of these bioactive compounds in different commercially available varieties for the cultivation of elite germplasm from the perspective of hill agriculture and sustainable development.In the study, total phenols were found to be highest in Jawahar-20 root, i.e., 82.714 mg/g (DW), followed by Poshita root, i.e., 64.02 mg/g (DW), while the least was found in Pratap leaf, i.e., 2.33 mg/g (DW). The concentration of total flavonoids varied significantly (p ≤ 0.05) from 1.98 ± 0.0.01 to 80.735 ± 4.33 mg QE/g (DW). Total flavonoids were found to be highest in Jawahar-20 root, i.e., 80.735 mg/g (DW), followed by Poshita leaf, i.e., 60.02 mg/g (DW), and least in Nimithli stem, i.e., 1.98 mg/g (DW). The total tannin content varied significantly (p ≤ 0.05) among the five varieties of Withania somnifera under the present study. The concentration of total tannin varied significantly (p ≤ 0.05) from 0.691 ± 0.51 to 36.09 ± 0.61 mg TAE/g (DW). Tannins were found to be highest in Jawahar-20 root, i.e., 36.09 mg/g (DW), followed by Poshita root, i.e., 29.287 mg/g (DW), while the least was found to be in Pratap seed, i.e., 0.682 mg/g (DW). Ortho-dihydroxy phenol was found to be highest in Jawahar-20 leaf, i.e., 40.081 mg/g (DW), followed by Jawahar-20 root, 19.31 mg/g (DW), and Poshita leaf, i.e., 19.02 mg/g (DW). Both recorded the same, and the least was found in Nimithli leaf, i.e., 0.95 mg/g (DW). Total antioxidant capacity was found to be highest in Jawahar-20 leaf, i.e., 16.70 mg/g (DW), followed by Jawahar-20 leaf, i.e., 11.51 mg/g (DW), and Poshita leaf, i.e., 11.31 mg/g (DW), both of which recorded the same almost least in Pratap leaf, i.e., 0.257 mg/g (DW). The DPPH activity was found to be highest in Poshita root, i.e., 92.39 at 1000 μg concentration, which was very near the ascorbic acid, i.e., 98.9 (a natural antioxidant), followed by Pratap leaf, i.e., 88.04, and least in Nimithli root, i.e., 58.36. The IC50 value of Pratap leaf was the least, i.e., 369.42, followed by Jawahar-20 stem, i.e., 370.32, and the highest IC50 value was found in Nimithli root, i.e., 877.22. The reducing power of five different varieties increased with increasing concentration. The varieties differed w.r.t. their total reducing power activity, i.e., the reducing power activity was highest in Poshita stem with an R2 value of 0.992, followed by Poshita root with an R2 value of 0.982, and least in Pratap seed with an R2 value of 0.565. Thus, Jawahar-20 and Poshita not only recorded higher phytochemicals but also withanolide A and withaferin A.

Investigating the Interaction of Endophytic Bacteria and Biochemical Compounds in Pearl Millet (Pennisetum glaucum)

Pearl millet (Pennisetum glaucum) is an important cereal crop in Asia and Africa. This study focuses on quantifying endophytic bacteria in several parts of the pearl millet plant—roots, stems, and leaves. Total phenolic content, orthodihydroxy phenols, total soluble sugars, protein levels, and enzymatic activity (peroxidase, polyphenol oxidase, and catalase) were all measured and linked with the amount of endophytic bacteria. The leaves have the highest total phenolic content, followed by the stem. Orthodihydroxy phenols were also significantly greater in leaves (1.82 mg catechol equi./g) than in stems and roots. Total soluble sugars showed higher levels in leaves (9.97 mg glucose equi./g), in stems (9.21 mg glucose equi./g) and in roots ( 6.83 mg glucose equi./g). Protein content exhibited significant variation among the plant parts, with leaves (10.63%) containing the highest protein content followed by stems and roots (8.47% and 6.67% respectively). Enzymatic activities, crucial for plant defence and growth, varied across the plant sections. Peroxidase activity was highest in roots (359.98 OD/g), followed by stems and leaves. Polyphenol oxidase activity was lowest in the roots (1.63 OD/g) and highest in the leaves with 2.19 OD/g, while catalase activity was the highest activity in the roots with 17.79 OD/g versus 14.79 OD/g and 14.63 OD/gin the leaves and Roots respectively. The number of Pearl millet endophytic bacteria in the roots is 16, whereas the amount in the stem is 12 and 10 in the leaves. This in-depth analysis sheds light on future research targeted at better understanding plant-microbe interactions and developing ways to improve plant health and productivity.

Arbuscular mycorrhizal colonization alters biochemical, molecular defense responses and root exudate composition against Phytophthora capsici infection in black pepper

Mycorrhizal symbiosis benefits the host plants in several aspects. Among the soil microbiota, AM fungi have established a substantial potential to decrease crop damage from plant pathogens in several crops, yet the mechanism of its action in black pepper has not yet been studied. In this study, we investigated the effect of mycorrhizal colonization on biochemical, molecular defense responses, and root exudates composition in the Phytophthora capsici -black pepper host-pathosystem. Four biochemical parameters such as total phenols, orthodihydroxy (OD) phenols, peroxidase activity, and lignin were studied to delineate the effect of mycorrhizal colonization upon pathogen inoculation. Total phenol, OD phenol, and lignin content increased consistently upon challenge inoculation with P. capsici as well as in AM alone inoculated plants in both leaves as well as roots. Similar peroxidase activity was noticed in AM alone and challenged inoculated plants. The quantitative polymerase chain reaction analysis showed that AM pre-inoculation led to up regulation of pathogenesis related genes viz., cAPX, Osmotin and β-1,3-glucanase, phenylalanine ammonia-lyase and NPR 1 in black pepper leaves and roots upon of P. capsici inoculation. Sole inoculation of P. capsici also positively influenced the copies of most genes studied. Root exudates of AM colonized plants showed higher fatty acid/fatty acyl compounds viz., tetradecanoic acid, n-hexadecanoic acid, octadecanoic acid, and nonacos-1-ene compared to P. capsici inoculated plants. On the other hand, most of the alkane hydrocarbons such as (z)-3-tetradecene, octylcyclohexane, 4-cyclohexylundecane, and decylcyclohexane were observed majorly in the root exudates of P. capsici inoculated plants. Multivariate analysis of the root exudate data revealed that AM colonization in black pepper roots normalized the content of root exudates during Phytophthora infection comparable to control plants. Our findings indicates that the AM colonization enhances the resistance of P. capsici in black pepper plants by alterations in defense enzymes and gene expression and root exudates composition.

Biochemical and Anatomical Characteristics of Basmati And Non-basmati Rice (Oryza Sativa L.) For Resistance To Foot Rot

Fusarium fujikuroi, the causal agent of foot rot disease, infects all the parts of rice, causing serious yield losses in different parts of the world. In order to understand the basis of disease tolerance, various biochemical and anatomical traits of ten days old healthy and infected basmati and non-basmati rice seedlings were compared. Total soluble sugar content was higher in healthy seedlings, while total phenols, orthodihydroxy phenols and total soluble proteins were higher in non-basmati rice seedlings post infection indicating the initiation of defence against the pathogen. Increase in the total antioxidant activity, enzymes and α-tocopherols in basmati rice cultivars post infection indicate the oxidative stress created by pathogen. Histopathological observations revealed hyphal and conidial growth in infected tissues of basmati cultivars whereas a complete and intact tissue was observed in healthy and infected counterparts of non-basmati cultivars. Bangladesh J. Bot. 51(1): 29-36, 2022 (March)

Voltammetric Behavior, Flavanol and Anthocyanin Contents, and Antioxidant Capacity of Grape Skins and Seeds during Ripening (Vitis vinifera var. Merlot, Tannat, and Syrah).

Skin and seed grape extracts of three red varieties (Merlot, Tannat, and Syrah) at different stages of ripening were studied for their total phenolic content (TPC) by using the Folin-Ciocalteu assay and for their total antioxidant capacity (TAC) by using spectrophotometric and electrochemical assays. Flavanol and anthocyanin compositions were also investigated using Ultra Performance Liquid Chromatography coupled with Mass Spectrometry (UPLC-MS). Results showed that seeds had the highest phenolic content and the highest antioxidant potential compared to skins at all stages of ripening. The highest TPC and TAC values were measured in seeds at close to veraison and veraison ripening stages. In skins, the highest values were found at the green stage, it was in accordance with the flavanols content. The voltammetric measurements were carried out using disposable single walled carbon nanotubes modified screen-printed carbon electrodes (SWCNT-SPCE). Three peaks on voltammograms were obtained at different oxidation potentials. The first anodic peak that oxidized at a low potential describes the oxidation of ortho-dihydroxy phenols and gallate groups, the second peak corresponds to the malvidin anthocyanins oxidation and the second oxidation of flavonoids. The third voltammetric peak could be due to phenolic acids such as p-coumaric acid and ferulic acid or the second oxidation of malvidin anthocyanins. The high linear correlation was observed between antioxidant tests and flavanols in skins (0.86 ≤ r ≤ 0.94), while in seeds, ‘r’ was higher between electrochemical parameters and flavanols (0.64 ≤ r ≤ 0.8).

Role of cell wall and cell membrane integrity in imparting defense response against Phytophthora capsici in black pepper (Piper nigrum L.)

The structural defense response of a black pepper line (04-P24) showing root resistance to Phytophthora capsici was studied in comparison with a highly susceptible line (Sreekara). Role of cell wall reinforcement and cell membrane integrity was analyzed. Cell membrane integrity was studied under hydroponic system in terms of leakage of electrolytes caused by the cell membrane damage due to pathogen entry. Root cell membrane rupture and resultant phenolic leakage were clearly visible in the form of color change of the liquid phase during the course of infection. Root leachates of Sreekara turned highly dark due to the increased level of phenol leakage which was proportional to the cell membrane damage. The root leachate was analyzed for change in conductivity, total phenols and ortho-dihydroxy (OD) phenols. Cell wall reinforcement of the vascular tissues of black pepper root upon pathogen inoculation was analyzed histochemically. Toluidine blue O and Maule staining differentiated the intensity of lignin deposition in the root cells of both lines and it was comparatively stronger in the resistant line. Scanning electron microscopy revealed that hyphae of P. capsici are not penetrating the root of 04-P24 supporting the finding that roots of this line don’t support Phytophthora infection.

Biochemical characterization of superior seedless variety of grape (Vitis vinifera L.) for resistance to anthracnose

Superior seedless is a promising variety of grape under moist and warm conditions may severely get hampered by anthracnose caused by Gloeosporium ampelophagum (Pass.) Sacc. To evaluate the biochemical reaction of the variety to the pathogen, the study was undertaken at Ludhiana (Punjab) in 2016. The percent disease index (0–9) scale, the morphological and anatomical characteristics were studied in the grape leaves. Chlorophyll a, chlorophyll b, total chlorophyll, carotenoids, total soluble proteins and free amino acid content decreased by 28.16, 3.94, 15.93, 85.86, 45.05 and 46.21%, respectively in anthracnose infected leaves as compared to healthy ones, while total soluble sugars, total phenols, ortho-dihydroxy phenols, flavonoids, ascorbic acid, proline, α-tocopherol, MDA content, peroxidase and polyphenol oxidase activity increased significantly by 9.75, 36.60, 21.80, 36.48, 23.04, 62.75, 90.47, 8.81, 10.49 and 3.12%, respectively. Increase in concentration of these chemical indicates the initiation of defense against G. ampelophagum in variety superior seedless.

Biochemical changes in rice yellow stem borer infested rice accessions

Biochemical constitution of 22 rice accessions showing susceptible, moderately susceptible, moderately resistant and resistant reaction to yellow stem borer, Scirpophaga incertulas (Walker) were studied in 40 days old transplanted healthy and stem borer infested plants under screen house condition. Total phenol increased by range of 13.11 to 43.66%, OD phenol increased by range of 20.00 to 61.29%, total sugar increased by range of 30.62 to 64.35%, reducing sugar increased by range of 33.68 to 64.48% and non-reducing sugar increased by range of 22.57 to 61.17% due to stem borer infestation in different rice accessions. The results depicted that the amount of total sugars, reducing sugar and non-reducing sugars in all susceptible genotypes was found higher compared to resistant and moderately resistant accessions. Higher level of total phenols and ortho-dihydroxy phenol were found in resistant and moderately resistant accessions as against susceptible accessions and indicating that these defensive compounds contributing towards the rice yellow stem borer resistance.

Induction of resistance in tea plants against Sclerotium rolfsii by application of amendments and associated changes in level of phenolic content

Application of neem cake,oil cake and organic amendments including cow- dung, rabbit manure and chicken manure on four varieties of tea Camellia sinensis (L.) O. Kuntze were evaluated for induction of resistance against Sclerotium rolfsii Sacc. The emphasis was on the involvement of phenolics. It was observed that total phenol levels (total phenol and ortho-dihydroxy phenols) increased in treated inoculated tea root varieties with S. rolfsii than treated uninoculated tea root varieties. Oil cake and rabbit manure induced a rapid and distinct accumulation of phenolics in contrast to neem cake, cow dung and chicken manure.

Evaluation of nutraceutical and antinutritional properties in barnyard and finger millet varieties grown in Himalayan region.

Five elite varieties of barnyard (Echinochloa frumentacea) and finger (Eleusine coracana) growing at northwestern Himalaya were investigated for nutraceutical and antinutritional properties. Barnyard millet contained higher amount of crude fiber, total dietary fiber, tryptophan content, total carotenoids, α-tocopherol compared to the finger millet whereas the finger millet contains higher amount of methionine and ascorbic acid as compared to the barnyard millet. The secondary metabolites of biological functions were analyzed and found that barnyard millet contained the higher amount of polyphenols, tannins and ortho-dihydroxy phenol content compared to finger millet. Among antinutitional compounds barnyard millet contained lower phytic acid content compare to finger millet whereas no significant difference in trypsin inhibition activity of barnyard millet and finger millet varieties were found. Barnyard millet contained higher acid phosphatase, α-galactosidase and α-amylase inhibitor activity compared to finger millet. Finger millet seeds contained about 10-13 folds higher calcium content and double amount of manganese content in comparison to barnyard millet seeds. Present study suggests that barnyard millet varieties studied under present investigation were found nutritionally superior compared to finger millet varieties.

Biochemical bases of resistance to brown planthopper (<italic>Nilaparvata lugens</italic>) (Stål) in different rice accessions

Host plant resistance has been a valuable tool in the management of planthoppers. The experiment was carried out to assess the level of total phenols, Ortho-dihydroxy phenols, Phenols, crude silica and total sugars in BPH (Brown Plant Hopper) affected rice leaves. Resistant varieties showed high amount of phenols, O.D. Phenols and crude silica as against low quantity of total sugars. These, biochemical basis of resistant method is also identifying the resistant variety against brown planthopper (<italic>Nilaparvata lugens</italic>) in rice.

Essential Oil Composition, Phenolic Constituents, Antioxidant and Pharmacological Activities of Thymus linearis Benth. Collected from Uttarakhand Region of India

sThe essential oil composition of Thymus linearis collected from two different locations (Harinagar; Nainital (TLHEO) & and Dhanachuli Nainital (TLEOD)) were analyzed by combination of GC and GC-MS. Total nine major constituents contributing to 93.6 % were identified in TLHEO and 89.3 % in TLDEO samples. Germacrene-D (65.1 %) and γ-terpinene (19.4 %) were identified as major constituents in TLHEO while thymol (66.8 %) and p-cymene (9.8 %) were identified in TLDEO. The oils and extracts were evaluated for DPPH radical scavenging ability, chelation of Fe2+, and Fe3+ reducing power activities. The oils and extracts both showed good to moderate antioxidant activity in a dose dependent manner. Both oils and extracts also exhibited significant pharmacological activities (antipyretic, analgesic, and anti-inflammatory activities) compared to the standards (paracetamol, indomethacin and ibuprofen) tested on Swiss albino mice. Total phenolic assay of the aqueous ethanolic extracts determined by Folin-Ciocalteu method revealed total phenol (5.15 mg /100 mg), flavonols (0.26 mg /100 mg) and orthodihydroxy phenols (0.4 mg/100 mg) in Harinagar collection and (4.65 mg/ 100 mg), (0.52 mg/100mg) and (0.18 mg/100 mg) in Dhanachuli collection respectively.

Phenolic Constituents, Ascorbic Acid, Tocopherols and Antioxidant Activity of Soybean Genotypes with Varying Seed Coat Colour

In order to determine the antioxidant potential, seeds of 20 soybean (Glycine max. L.) genotypes varying in seed coat colour viz. black, brown, green and yellow were compared for their phenolic constituents, vitamins and antioxidant activities. Genotypes with different seed coat colour showed wide variations of total phenols (TP) from 9.3–23.56 mg gallic acid equivalents, total flavonols (TF) 7.77 to 20.25 mg/g rutin, orthodihydroxyphenols (OHP) 0.232 to 0.835 mg/g catechol equivalents, anthocyanins 0.92 to 3.21 mg/g, ascorbic acid 0.124–0.302 mg/100g and tocopherols 6.22 to 30.66 mg/100g. Mean TP, TF, and OHP were significantly higher in black group as compared to brown, green and yellow soybeans. Ferric reducing antioxidant power (FRAP), 2, 2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity, hydroxyl ion and nitric oxide scavenging capacity of soybean genotypes were significantly different not only between groups but also among genotypes within each group.

Defence responses of cucurbitaceous rootstocks and bitter gourd scions against root knot nematode Meloidogyne incognita kofoid and white

Defence Responses of Cucurbitaceous Rootstocks and Bitter Gourd Scions against Root Knot Nematode Meloidogyne Incognita Kofoid and White Pot culture experiments were conducted under in vitro to understand the biochemical changes takes place during nematode attack and to identify resistant rootstocks for grafting with bitter gourd scions. Results revealed that, three genotypes viz.,Kumatikai (Citrulus colocynthis), African horned cucumber (Cucumis metuliferus) and pumpkin (Cucurbita moschata) encompass the lowest value for number of galls per gram root, egg masses per gram root and numbers of females per gram of root and showed resistant reaction followed by two rootstocks viz.,Sponge gourd (Luffa cylindrica) and mithipakal (Momordica charantia var. muricata) bare minimum values and are moderately resistant. These resistant reaction yet again confirmed by assessment of defence enzymes viz.,phenylalanine ammonia lyase (PAL), peroxidase (PO), polyphenoloxidase (PPO), Acid phosphatase and biochemical components viz., total phenol and ortho dihydroxy phenol (OD phenol). The present study indicates that rapid augmentation of PAL, PO, PPO, acid phosphatase, total phenol and OD phenols activities were noticed in resistant rootstocks viz., C. colocynthis, C. metuliferus and C. moschata and started to increase at 24 hours after inoculation, reached maximum at 96 hours after inoculation and thereafter declined. Similarly, native poly acralamide gel electrophoresis (PAGE) analysis revealed that one to six isoforms of defence enzymes were observed in aforementioned resistant rootstocks whereas fewer isoforms with less intensity were noticed in susceptible rootstocks and bitter gourd scions. These results suggest that the aforementioned resistant rootstocks are potential source for managing root knot nematode menace in bitter gourd by grafting...

Antioxidant and antimicrobial activities in flowers ofGentiana kurrooRoyle, a critically endangered plant from Garhwal region of Uttarakhand, India

The motive of present study was to quantify various phytochemicals and evaluate antioxidant and antibacterial activities of flower extract of Gentiana kurroo Royle. The dried fine powder of G. kurroo flowers was extracted with methanol. Several phytochemicals were quantified using this methanolic extract. Biochemical assays for total antioxidant activity, diphenylpicrylhydrazyl (DPPH) scavenging activity, ferric reducing power (FRAP), metal ion chelation activity and total reducing activity were performed to quantify the antioxidant activity. The antibacterial activity was determined by MTT cytotoxicity assay. Methanolic extract of flower was found enriched with several bioactive compounds like phenols, flavonoids, flavonols, tannins, orthodihydroxy phenols, anthocyanins and proanthocyanidins. Flowers had detected with impressive antioxidant activities. DPPH activity and total reducing activity were even at par with several standard antioxidant compounds. The antibacterial activities were positively correlated with antioxidant capacity.

Antioxidant Potential of the Giant Mushroom, Macrocybe gigantea (Agaricomycetes), from India in Different Drying Methods.

Free radicals are responsible for several diseases like cancer, atherosclerosis, gastric ulcers, and several others. Studies have shown that mushrooms possess antioxidant activity and Macrocybe gigantea was recently added to the list of mushrooms under cultivation in India. The methanolic extracts were prepared from lyophilized and oven-dried samples of MA1 and MA2 strains of M. gigantea and their antioxidant properties were studied. MA2 showed comparatively higher total antioxidant activity (111.88 µg/mg) than MA1 (97.00 µg/mg). The scavenging activity on 2,2'-diphenyl picryl hydrazyl free radical (74.41%), ferrous chelating (83.74%), reducing power (0.371), and superoxide anion radical (72.05%) was significantly higher in freeze-dried MA2 than MA1 at 200 µg/mL. Correspondingly, the EC50 values were lower in freeze-dried states (96.03 µg/mL, 95.00 µg/mL, and 68.12 µg/mL in MA2 and 105.12 µg/mL, 109.8 µg/mL, and 74.60 µg/mL in MA1) than in oven-dried states (97.97 µg/mL, 120.2 µg/mL, and 125.33 µg/mL in MA2 and 108.3 µg/mL, 131.2 µg/mL, and 147.5 µg/mL in MA1, respectively). In addition, total phenolic, total flavonoid, and ortho-dihydroxy phenol content was examined and their values were comparatively higher in freeze-dried MA2 (18.00 mg/g of gallic acid equivalents, 1.67 mg/g of quercetin equivalents, and 1.10 mg/g of catechol equivalents, respectively) than in MA1 and oven-dried states in both strains. Further, MA2 showed lower EC50 values in freeze-dried samples than MA1 and oven-dried states in both strains. These results suggested that MA2 contains higher antioxidant potential than MA1 and freeze-drying by lyophilization retains higher antioxidants than heat drying by a hot air oven in both the strains; thus, they can be a good source of nutraceuticals.

Antioxidative Properties and Mineral Composition of Defatted Meal of Oileferous Brassica Germplasm

Brassica defatted meal possess technologically functional properties due to presence of health-promoting phytochemicals such as phenolics, vitamins C & E, phytic acid, flavonoid, promising anticarcinogenic dietary compounds and has the potential to be a good ingredient for use in aquaculture, animal and human diets. The present study focused on evaluating the antioxidative properties and mineral composition of defatted meal of 25 oileferous Brassica genotypes. The study revealed that all the methanolic extracts of defatted meal showed good to moderate in vitro antioxidative activity in a dose dependent manner at levels of 5-20 mg/mL in comparison to standard antioxidants viz. gallic acids, catechin and BHT. The maximum reducing power was observed in Bio22 at 700 nm in a dose dependent manner followed by Bio24 and Bio9. The methanolic extracts of Bio2, Bio4 and Bio20 exhibited maximum scavenging activity at dose level of 20 µL of the extract. The chelating activity was observed to be maximum in Bio11 followed by Bio14 and Bio24. The total phenol content (TPC) and ortho-dihydroxy phenol content varies from 0.057-0.112 g/100 g and 0.007-0.027 g/100 g respectively. Mineral analysis revealed different quantitative make up of N, P, K, Ca, Mg, Fe, Mn, Cu and Zn in all the 25 genotypes.

Biochemical Investigation on Antioxidative and Antinutritional Characters of Yellow SeededBrassicaGenotypes for Quality Assessment

Yellow seeded Brassica is one of the most important oilseed crop cultivated in many parts of the world. The oil is consumed predominantly as edible oil and the defatted meal cake is utilized as animal/poultry feed. In the present study, intact seeds and defatted meal of 12 yellow-seeded Brassica genotypes evaluated for the presence of anti-oxidative and anti-nutritive factors. The maximum phenolic, orthodihydroxy phenols, flavonoid contents observed for Bio 39(16.946 mg/g), Bio 30(2.38 mg/g) and Bio 39(8.282 mg/g) repectively. The crude fibre, phytic acid and glucosinolate contents were found to be minimum in Bio 21 (6.95%), Bio 2 (3.632%) and Bio 38 (54.324 μmole/g) respectively. Vitamin C content was maximum in Bio 36 and Bio 3. The α-tocopherol content was observed to be maximum Bio 2 (61.875 mg/100g). The total antioxidant activity varied from 5.95 mg AAE/g in Bio 28 to 14.395 mg AAE/g in Bio 39. The DPPH radical scavenging activity was observed to be maximum in Bio 30 and reducing power was found to be maximum in Bio 21(0.867 ± 0.023). The present findings may be utilized for determining the quality status to ascertain their potential for development of better cultivar.

Traditional landraces of rice for blast (Magnaporthe oryzae) resistance and analysis of biochemical components involved in disease reaction

Rice blast disease is the major biotic threat to rice production and the pathogen Magnoporthe oryzae is highly genetically diverse. Rice germplasm are the important reservoirs of valuable traits possessing specialty uses and tolerance to various biotic and abiotic stresses. The present study was aimed to evaluate the collected landraces of rice against blast and to understand the biochemical changes in landraces in response to blast infection. Field evaluation of 186 rice landraces collected from Karnataka state, along with improved lines resulted in identification of land races with consistent resistance to blast. The key biochemical factors involved in disease reaction, Phenol, orthodihydroxy phenol, protein and enzyme PAL at different crop growth stages was studied. Total phenol, OD phenol and PAL accumulation and increase were rapid and more in resistant landraces as well as in improved lines due to blast infection. Landrace Beesginsali, Siddasala and Casebatta showed highly resistant reaction with disease grade either 1 or 0 and lesion type A or B. Enhancement of defense responsive biochemical components was quick and more in these landraces. These resistant landraces may serve as source of novel allele/genes to blast for future study.

Biochemical defense responses of black pepper (Piper nigrum L.) lines to Phytophthora capsici

A study on biochemical factors involved in black pepper defense response against Phytophthora capsici, was carried out in P. capsici susceptible (Sreekara) and resistant (04-P24, shows root resistance to the pathogen) black pepper lines. Seven important factors – change in membrane conductance, total phenols, orthodihydroxy (OD) phenols, lignin and defense related enzymes (peroxidase, β-1,3 glucanase and β-1,4 glucanase) – were studied under uninoculated and pathogen (P. capsici, isolate 06-04) inoculated condition to know the preformed and induced responses. The pathogen was inoculated (soil inoculation) and plants were observed for changes, at 24 h intervals for 10 days. On 8th day after inoculation symptoms started appearing on Sreekara and increased the severity till 10th day. Both root and stem samples were subjected for biochemical analysis. Of the factors analyzed, it was found that membrane conductance, OD phenol, lignin and peroxidase activity play significant role in root resistance to P. capsici in 04-P24. Light microscopy of the portion of root – where pathogen found attached – was also done.