Tuber Dioscorea Research Articles

Cure, mechanical and swelling characteristics of composites of neoprene rubber and starch from non-edible variety of dioscorea tuber

Composites of Polychloroprene rubber (CR, Neoprene rubber) reinforced with starch from non-edible variety of dioscorea tuber were prepared using three different vulcanizing systems. The cure, mechanical, solvent resistance and biodegradable characteristics of the composites were studied. The addition of starch from dioscorea tuber was found to improve CR’s tensile strength. The maximum torque value increases with the loading of filler and it was found to be the highest at 20 phr. The addition of starch from dioscorea tuber was found to improve CR’s tensile strength and highest value observed at 20 phr. Among the different curing systems studied, the modified DCP system shows maximum mechanical properties, optimum properties of the composites are at 20 phr. The values of the swelling coefficients were determined by examining the intake of the solvents N, N-dimethylformamide, acetonitrile, dimethyl sulfoxide and water by the composites. The soil burial test indicated that biodegradability of CR enhanced with the addition of starch. The findings of mechanical properties are supported by studies using scanning electron microscopy. Since starch is a naturally occurring biopolymer, adding it encourages microbial activity, which breaks down the composite components. This quality is essential for resolving plastic waste-related environmental issues. It is anticipated that the findings of this study will aid in the development of materials for specific product applications like gasoline hoses, tire sidewalls, seals, and so on.

Study of Total Phenols, Flavonoids, Antioxidant and Antibacterial Activities from Dioscorea hispida Tubers

The tubers of Dioscorea hispida Dennst., a Dioscoreaceae plant, contain flavonoid molecules and plant secondary metabolites that are antioxidants and antibacterials. In this study, the total phenolic content and flavonoids from the ethanol extract and fraction (n-hexane and ethyl acetate) of Dioscorea tuber were investigated for their antioxidant and antibacterial properties. Fractionation with n-hexane and ethyl acetate followed by diffusion with 96% ethanol. The Folin-Ciocalteau reagent measured total phenol at 765 nm, and the AlCl3 method measured total flavonoid at 440 nm using a visible spectrophotometer. The DPPH assessed the antioxidant activity, whereas the antibacterial activity against Staphylococcus aureus and Escherichia coli was determined using agar diffusion on paper discs. The extract, n-hexane fraction, and ethyl acetate exhibited total phenolic content of 33.02, 5.95, and 156.33 mg GAE/g extract, respectively. Similarly, the total flavonoid content was measured at 20.26, 14.31, and 74.02 mg QE/g extract. The extract, n-hexane fraction, and ethyl acetate of the Dioscorea tuber exhibited minimum inhibitory concentrations (MICs) of 8.25, 7.76, and 10.30 mg/mL against S. aureus and 8.51, 8.31, and 12.05, against E. coli, respectively. The findings of this study indicate that the ethanol extract and n-hexane fraction derived from Dioscorea tubers exhibited comparatively diminished antioxidant and antibacterial properties in comparison to the ethyl acetate fraction. Furthermore, the ethyl acetate fraction exhibited elevated concentrations of total phenols and total flavonoids in comparison to the remaining fractions.

Foliar Morphological and Micromorphological Variation of Dioscorea Species in Terengganu, Malaysia

Dioscorea species are recognised for their production of tuberous roots and are referred to as "ubi" by the local population in Malaysia. The tubers of Dioscorea are commonly consumed by individuals residing in the East Coast region of Peninsular Malaysia as their primary food source. These tuberous roots are particularly abundant during the monsoon season, typically observed in local markets from October to December. Due to the availability and potential of this Dioscorea species, a study about the variation in morphological and micromorphological study of the leaves of three species of Dioscorea in Terengganu was conducted in order to identify the variation in their morphological and micromorphological characteristics. The selected species are D. esculenta (ubi itik), D. alata (ubi besar), and D. hispida (ubi gadong). The collection has been done in the Kuala Berang Terengganu area. The leaves morphological characteristics such as leaf colour, leaf type, leaf shape, leaf size, leaf margin and hairiness of adaxial and abaxial surface and shape of leaves and petiole were recorded. The morphological descriptors were suggested by the International Plant Genetic Resources Institute (IPGRI) / International Institute of Tropical Agriculture (IITA). The foliar anatomical studies of selected Dioscorea were followed by the standard tissue sectioning procedures and the observation was done by using light microscopy. The morphological study shows the variations in leaf shape, leaf base, and leaf size but they have the similarity in term of leaf margin shape and leaf attachment which is all species are petiolate. The micromorphological study shows the presence of non-glandular and uniseriate trichomes which is only obtained in the D. esculenta and D. hispida. Hence, this study contributes to the information on these species, especially for classification and identification of Dioscorea species.Keywords: Dioscorea, morphology, foliar anatomy

Discrimination of Dioscorea species (Chinese yam) using FT-IR integrated with chemometric approach

Dioscorea oppositifolia is an important crop and functional food. D. oppositifolia tuber is often adulterated with D. persimilis, D. alata, and D. fordii tuber in the commercial market. This study proposed an integrated Fourier transform infrared spectroscopy (FT-IR) with chemometric approach to differentiate these four Dioscorea species. A total of 107 Dioscorea spp. tuber samples were collected from different locations in China. Principal Component Analysis (PCA), PCA-Class, and Orthogonal Partial Least Square Discriminant Analysis (OPLS-DA) were utilised to classify the FT-IR spectra. In this PCA is unable to differentiate the Dioscorea spp. tuber effectively. However, PCA-Class and OPLS-DA can distinguish spp. these 4 species Dioscorea tuber with high accuracy, sensitivity, and specificity. Additionally, the RMSEE, RMSEP and RMSECV values for OPLS-DA model were low, showing that it is a good model. The combination of FT-IR with the PCA-Class and OPLS-DA is practical in discriminating Dioscorea spp. tubers.

The Utilization of Dioscorea Tuber in Self-Rising Starch: a Review

Self-rising starch is a development product of self-rising flour. This product minimizes the process, especially in the salt and leavening agent weighing stage, so that it reduces the time in the serving process. Self-rising flour is generally made of wheat flour. Currently, due to some medical considerations, many people cannot consume this product. Based on some research results, gluten compound in wheat flour or wheat triggers for the development of type-1 diabetes. This fact has caused Indonesia to be ranked fifth in the world for the diabetic diseases. Thus, one of the ways to overcome this problem is by utilizing the raw materials originating from Indonesia too, namely tubers. Indonesia has a variety of tubers. Some of these tubers, however, have not been explored. These tubers have not only the function as the good sources of carbohydrates but also the bioactive compounds and more functional values, such as water soluble polysaccharides (WSP), diosgenin, inulin and glycemic index. They increase the functional properties of the starch that are produced. The tubers that currently have not been cultivated are the genus Dioscorea. The various tubers that are included in dioscorea family are uwi, gembili, gadung, tomberoso and jebubuk. All of these tubers are good sources of carbohydrates. Uwi, gembili and gadung are tubers that have been cultivated by the people for many years. On the hand, tomberoso and jebubuk tubers grow wildly in the forest that only become the foods for the wild animals in it. The starch derived from the disccorea tubers can be used as self-rising starch because it has the property as food developer. It contains high carbohydrates and bio-active compound, therefore, it is healthier to consume.

Título en español.

Este valioso sistema enzimático puede tener muchas aplicaciones para trabajar en los más diversos campos científicos. Sería también, un sistema muy conveniente para futuros estudios sobre la biosíntesis de los esteroides en las plantas. Por otra parte, la incorporación de radiactividad dentro de esteroides sapogénicos podría simplificar la producción de aquellos productos farmacéuticos radiactivos derivados de éstos.

Health Beneficial Phytochemicals in Dioscorea caucasica Lipsky Leaves and Tubers and Their Inhibitory Effects on Physiologically Important Enzymes.

Dioscorea caucasica Lipsky is a tertiary relict endemic plant naturally growing in the western part of the trans-Caucasus regions; it has adapted and successfully grows in the temperate region of the Baltic countries. Information about its phytochemical composition and bioactivities is rather scarce. This study reports the results of the identification of 41 compounds in D. caucasica leaf and tuber hydroethanolic extracts using UPLC-QTOF/MS. Organic acids were found in both extracts; hydroxycinnamates and flavonoids were the main phytochemicals in the leaves, while steroidal glycosides, fatty acids (mainly hydroxylated) and carbohydrates were found in the tubers. Leaf extracts inhibited enzymes in a dose-dependent manner and were remarkably stronger inhibitors of physiologically important enzymes, namely α-amylase (48.6% at 480 µg/mL), α-glucosidase (IC50 = 41.99 and 47.95 µg/mL with and without 0.1 M Na2CO3), acetylcholinesterase (45.85% at 100 µg/mL) and angiotensin-converting enzyme (IC50 = 829.7 µg/mL), most likely due to the presence of some quantified polyphenolic antioxidants. The mode of inhibition of α-glucosidase and acetylcholinesterase was assessed via kinetic studies based on Lineweaver–Burk inhibition plots. Leaf and tuber extracts acted as mixed-type and competitive inhibitors of α-glucosidase, respectively; the leaf extract demonstrated an uncompetitive inhibition mode of acetylcholinesterase. It is expected that this new knowledge of D. caucasica will serve for its valorization in developing new health beneficial ingredients for functional foods and nutraceuticals.

Phytochemical and Antioxidant Analysis of Fermented ‘Dayak’ Wild Yam (Dioscorea hispida Dennst), Purple Yam (Dioscorea alata) and Air Potato (Dioscorea bulbifera L.) Tuber Flour

Tubers of Dioscorea spp. contain many compounds that have physiological activity that can act as antioxidants and are proven to have various health uses. Antioxidant compounds have a very important role in the health of the human body. Various scientific evidence show that antioxidant compounds reduce the risk of various chronic diseases such as cancer and coronary heart disease.The study aimed to determine the phytochemical content and antioxidant activity of fermented Dayak wild yam (Dioscorea hispida Dennts), Purple Yam (Dioscorea alata var. Purpurea) and Air Potato (Dioscorea bulbifera) tubers flour was carried out. Phytochemical testing was carried out by the Harborne method (1987) and antioxidant activity using DPPH (1,1-diphenyl-2-picrylhydrazyl) method. The data obtained were analyzed descriptively from the average value of 3 replications for each parameter. Phytochemical analysis results showed the presence of alkaloids, tannins, triterpenoids and carbohydrates. While the results of the antioxidant activity testing showed that the IC50 value of fermented Dayak wild yam flour (WYF) was 227.43 ppm, air potato tuber flour (APF) was 15.77 ppm and purple yam tuber flour (PYF) was 7.70 ppm. Thus it can be concluded that all three tubers belonging to Dioscorea spp. all of them contain antioxidants with the order of the strength of antioxidant activity sequentially from the strongest to the weakest are PYF, APF and WYF.

Role of Nitrogen in Tuber Phenol Content and Subsequent Tuber Quality Preservation in Calcium Nitrate-Fertilized Dioscorea Alata Variety Alakisa

In a study of proximate, mineral and phenol content in calcium nitrate-fertilized Dioscorea alata variety Alakisa, nitrogen stands out among the two minerals in the fertilizer, in the enhancement of phenol for tuber quality preservation. The experiment was a 3 by 3 factorial arranged in RCBD (randomized complete block design) with 3 replicates and 9 treatment combinations. The mainplot treatment was calcium nitrate soil amendment at the rates 0, 1 and 2 kg ha -1, applied at 3MAP (months after planting). The subfactor treatment was Ca (NO3)2 foliar spray at the rates O, 100 and 500 mg Ɩ-1 applied at 5MAP. Tuber proximate, mineral and phenol content were analyzed in triplicates per treatment and also after incubation with Botryodiplodia  theobromae for two weeks. Ca, Mg and K were comparable in the main plot treatments, whereas N, Fe, P and S were significantly higher either in one or both Ca(NO3)2 treatments  (1, 2 Kg ha-1) over the control. N, Mg, K and S were comparable in the foliar spray treatments, whereas Fe and P were higher in the 0.6 and 1.2 ml Ɩ-1 foliar spray treatments than the control. Phenol content was higher in the soil amendment treatments (1 and 2 kg ha-1) than the control, but was comparable in the foliar spray treatments. Interaction effects followed similar trends as in the main plot/subplot treatments. Ca correlated significantly with Mg (r = 0.5784). There were significant correlations between Nitrogen (N) and Phenol, S, P, Fe and tuber weight per plant, r = 0.9196, 0.9383, 0.7339, 0.8522 and -0.4602 respectively. S correlated significantly with Fe (r= 0.8502) and P with Phenol, N, S and Fe (r=0.8474, 0.7339, 0.7840 and 0.8130 respectively). Fe and S correlated significantly with Phenol (r = 0.8568 and 0.9758) respectively. Thus N (nitrogen) enhanced phenol as well as 3 other minerals, each of which in turn enhanced tuber phenol content with its antimicrobial potential, for rot resistance and subsequent quality preservation. Significant negative correlations were indicated between crude fibre and Phenol (r = -0.4916), crude fibre and crude protein (r = -0.5975), crude protein and moisture (r = -0.8848). This indicates that as phenol is promoted by the four minerals, this will reduce crude fibre and whereas low crude fibre will promote high crude protein, the latter will promote low moisture. A negative significant correlation has been reported between moisture and shelf life in Dioscorea tubers in literature. Promotion of high crude protein by low crude fibre (r = -0.5975), will also result in high dry matter (r = 0.8848). There was an increase in crude protein across all treatments (soil amendment and folia spray) in the incubated tubers. Dry matter increased across 2 treatment (soil amendment), and 1 treatment (foliar spray) in the incubated tubers, and did not change in the remaining treatments. There was significant correlation between phenol and carbohydrate (r = 0.4350). Carbohydrate is the highest (% dry matter) proximate component, relative to others in variety Alakisa, and because N, P, S and Fe correlated significantly with phenol and phenol with carbohydrate, it was expected that carbohydrate may not change/may increase in the 2 – week incubation. But carbohydrate decreased across all treatments probably because it is also being used up is synthesis of Phenol via the Shikimic pathway as in diseased tissue. Ash which increased across all treatments (soil amendment and foliar spray), had a significant negative correlation (r = -0.4158) with Carbohydrate and thus may have also influenced decrease in Carbohydrate. Fat was the lowest proximate content relative to others and decreased across treatments in the 2 – week incubation. Phenol analysis after the incubation indicated a decrease across all treatments, therefore there ought to be a future trial in which total phenolic compounds (not only phenol) content, as well as minerals and proximate content in calcium nitrate-fertilized variety Alakisa will be monitored in a time-related longer incubation (with B. theobromae) of about 6 to 8 weeks.

Dioscorea Alata Tuber Proteome Analysis Uncovers Differentially Regulated Growth-associated Pathways of Tuber Development.

During its life cycle, the Dioscorea tuber undergoes multiple morphological and biochemical changes. To gain a better understanding of the metabolic changes associated with tuber growth, a stage-specific gel-free proteome analysis of four distinct morphological stages namely germinating tuber (S1), degrading tuber (S2), new tuber formation (S3) and tuber maturation (S4) was done and validated by principal component analysis. A comprehensive data set identifying 78.2% of the total 3,681 proteins was generated. PANTHER and KEGG MAPPER revealed both expected (carbohydrate metabolism and redox regulation) and novel biological processes (transcription factors and hormonal regulation) characteristic for each developmental stage. Higher abundance of the enzymes of ascorbate-glutathione cycle and carbohydrate metabolism was detected during tuber germination (S1) and tuber formation stages (S3) in comparison with the mature tuber. The presence of ethylene biosynthesis components during tuber formation hints toward its probable role in postharvest shelf life. The data set comprehensively describes the proteome of Dioscorea tuber and provides growth-specific markers for tuber germination (ascorbate peroxidase, monodehydroascorbate reductase, invertase) and tuber formation (sucrose synthase), which were validated by enzyme activity assays and Western blotting. The study provides information that may influence the direction of research for improving the productivity of this under-utilized and largely neglected crop.

Chemical variation of five natural extracts by non-polar solvent

Chemical compounds of wood preservation from plants vary and are not known specific to the species. Chemical analysis of plants is responsible to ensure active compound in natural extracts wood treatment. There are many sources of natural extracts found in Indonesia that were explored for wood preservatives chemicals. They are bark of acacia and alstonia, leaves of orthosiphon and azardirachta and Dioscorea tubers The present study was aimed at investigating the variation of the chemical constituent of natural extracts material of wood preservative through GC-MS analysis. Five natural extract sources were acacia bark (Acacia spp.), pulai bark (Alstonia scholaris), kumis kucing leaves (Orthosiphon spp.), mimba leaves (Azardirachta indica), and gadung tubers (Dioscorea spp.). Two non-polar solvents, i.e., n-hexane and petroleum ether were used for five natural source extractions following ASTM soxhlet extraction. The research showed that triterpene and fatty acid derivatives were the major compounds present in five natural extracts. They were lupeol; 7,22-Ergostadienone; Lup-20(29)-en-3-one; Lup-20(29)-en-3-ol, acetate, (3.beta.)-; urs-12-en-3-one; ethanol,2,2-diethoxy-; stigmasta-5,22-dien-3-ol, acetate,(3.beta.)-; 5H-3,5a-Epoxynaphth[2,1-c]oxepin, dodecahydro-3,8,8,11a-tetramethyl-; linoleic acid; naphthalene, 1-methyl-. These compounds have been assigned as the possibly responsible to against termites or fungi.

Sex-specific variations in phytochemicals and antimicrobial potentiality of Dioscorea

BackgroundThe monocotyledonous herbaceous crop Dioscorea is native to tropical and temperate regions of the world. Dioscorea tubers are dioecious in nature, have colossal therapeutic potentiality, and are frequently used in traditional medical practices throughout the world. Most of the research works are aimed to determine the medicinal property, nutritions, antinutrients, and biological activities of Dioscorea spp. without specifying the sexes of Dioscorea which promoted us to carry out this present research work.ResultsSex-specific variation of phytoconstituents, antioxidants, and antimicrobial efficiency in tubers was appraised. The results obtained from this study divulge existence of significant quantitative variation between the male and female tubers. The female tubers are superior in acquiring phytochemicals compared to male counterparts and acquired maximum antioxidant and antimicrobial potentiality.ConclusionThis study will offer an apposite baseline for further sex-specific assessment which can be directed towards both qualitative and quantitative amelioration of medicinally important noble compounds by exploiting modern scientific strategies leading to their active participation in nutraceutical industries.

Physicochemical, Morphological, and Molecular Properties of Starch Isolated from Dioscorea and Oxalis Tubers from Hidalgo State, Mexico

AbstractStarches are isolated from tubers of Dioscorea and Oxalis tuberosa (OT) grown in Hidalgo and surrounding areas. The starch particle sizes of Dioscorea bulbifera (DB) show a bimodal distribution, whereas those of Dioscorea mexicana Schidw (DM) and OT show unimodal distributions. The Dioscorea starch granules have a round shape, while those of OT have an elongated shape. Significant differences (p < 0.05) in pasting properties among the starches are observed, with DB showing the lowest viscosity value and DM showing the highest viscosity value. The peak and pasting temperatures show similar patterns, with higher values observed in the Dioscorea starches than in the OT starch. The gelatinization temperature values are low in the DB starch, compared to the DM and OT starches, which is consistent with the small granule size in DB. The interval in amylose content in the starches is 25.9% to 32.3%, classifying as normal starches. Molecular analysis reveals differences in molar mass and gyration radius between the amylopectin and amylose fractions of the starches, parameters that influence the physicochemical, pasting, and enzymatic hydrolysis characteristics of starches. The characterization of the tuber starches in this study reveals the potential of these under‐used food crops.

Traditional processing associated changes in chemical parameters of wild Yam (Dioscorea) tubers from Koraput, Odisha, India

Wild yam tuber considered as famine food and played a prime role in the food habit of tribal people of Koraput district of Odisha, India. The tribal people employed a range of processing of these yams such as boiled, soaked and sun dried for detoxification of antinutrients in accordance with their needs. There is a scarcity of documented information on their nutrient composition/retention by traditional processing methods. The current study assessed the traditional processing (boiled, soaked and sun dried) associated changes in chemical composition and physico-functional characteristics of 6 wild and 1 cultivated Dioscorea tubers collected from Koraput, India. Different processing led to a significant reduction of proximate compositions and nutrient content compared to the raw tuber, whereas physico-functional parameters increased significantly (p<0.05). In addition, there was significant decrease in the antinutrients, minerals and vitamin content by different processing in studied yam species. Results suggested that wild Dioscorea tubers as safe food sources for mass consumption and should be used in boiling form, as it retains higher nutrients coupled with significant removal of antinutritional compositions.

Comparative Studies on the Susceptibility of Three Tubers of Dioscorea Species to Dry Rot in Anyigba, Kogi State

Various yam species are cultivated but white yam (Dioscorea rotundata Poir.), water yam (Dioscorea alata L.) and yellow yam (Dioscorea cayenensis Lam.) are among the most cultivated in Nigeria. The Susceptibility of three tubers of Dioscorea species (D. rotundata, D. alata and D. cayenensis) to dry rot pathogens was investigated. Isolation was made from rotted tuber tissues, followed by pathogenicity test and identification of isolates; two fungal species Aspergillus niger and Rhizopus stolonifer were isolated and identified as the major fungi causing yam tuber dry rot in the study area. There was significant difference (P<0.05) in the susceptibility of the various Dioscorea tuber species studied to rot caused by Aspergillus niger [D. rotundata (20mm), D. alata (11mm) and D. cayenensis (3.5mm)] and Rhizopus stolonifer [ D. rotundata (17.5mm), D. alata (10mm) and D. cayenensis (2mm)]. The phytochemical contents of the three tubers of Dioscorea species examined also varied significantly, with the bioactive substances of D. cayenensis and D. alata relatively higher when compared to D. rotundata. Therefore, this research reveals that three metabolites; Saponin, Flavonoid and Tanin constitute the major trait for resistant ability of D. cayanesis and D. alata to dry rot causing pathogen. Therefore, it is necessary that the differences in susceptibility be considered when developing yam barns. Also, researchers should work on genetically improving the susceptible white yam (D. rotundata) which is commonly eaten by millions of Nigerians with a possibility of increasing the quantities of the deficient phytochemicals.

Pengendalian Ulatgrayak (Spodoptera litura F.) dengan Ekstrak Ubi Gadung dan Ekstrak Buah Maja

A rmyworm (Spodoptera litura F.) is one of the important polyphag leaf pests that attacks almost all crops. The objective of this study was to determine the effect of various concentrations of bioinsecticide made of dioscorea tuber and aegle fruit extract on larval mortality. The research was conducted at the crop laboratory, Lampung State Polytechnic since October 2017 until December 2017. The experimental design is a completely randomized design with six treatments and four and replications. The parameters observed is mortality of armyworm larvae, which would then be analyzed using fingerprint of different varieties. That result showed that dioscorea tuber and aegle fruit extract has affected on larval mortality armyworm. Pure (100%) dioscorin tuber extract exhibited the highest larval mortality.

Assessment of sex specific relationship among nine Dioscorea species found in Tripura by using morphometric and micro morphometric markers

Present study deals the assessment of inter and intra specific relationship among nine Dioscorea species by using morphological and micro-morphological markers. To fabricate the relationship among the Dioscorea species 37 micro-morphometric traits were adopted. Wild Dioscorea tuber is a potential substitute food supplement offering the seasonal food security to the indigenous forest dwellers of Tripura. In nature, Dioscorea species exhibit high morphological variation. In spite of enormous information available regarding the interspecific relationship in dioecious Dioscorea species meager information are existing with respect to sexes. PCA analysis revealed that two vital components account for 58.21% of total variation among the traits. PCA I was strongly associated (r > 0.5) with fourteen morphological traits. The first seven PCs have Eigen value greater than 1 together explain 95.17% of the total variance. The results of cluster analysis and dendrogram developed initially produce four main groups at level 7.31. The results obtained may contribute to effective conservation and improvement practices of Dioscorea with good agronomical traits which may be attributable with the utilization of Dioscorea genetic resources.

Spectrophotometric Analysis of Vitamin A and Vitamin E in Different Species of Dioscorea Tuber

Spectrophotometric Analysis of Vitamin A and Vitamin E in Different Species of Dioscorea Tuber

Phytochemicals-induced hormesis protects Caenorhabditis elegans against α-synuclein protein aggregation and stress through modulating HSF-1 and SKN-1/Nrf2 signaling pathways

Mild stress activates the adaptive cellular response for the subsequent severe stress called hormesis. Hormetic stress plays a vital role to activate multiple stress-responsive genes for the benefit of an organism. In tropical regions of world, tubers of Dioscorea spp. has been extensively used in folk medicine and also consumed as food. In this study, we report that the phytochemicals of Dioscorea alata L., tubers extends the lifespan of nematode model Caenorhabditis elegans by hormetic mechanism. We showed that the low dose of tubers extract at 200 and 300 μg/mL extends the mean lifespan of wild-type worms, whereas higher doses are found to be toxic. Supplementation of tubers extract slightly increased the intracellular ROS in second-day adult worms and it might activate the adaptive stress response, which protects the worms from oxidative and thermal stress. Transgenic reporter gene expression assay showed that extract treatment enhanced the expression of stress protective genes such as hsp-16.2, hsp-6, hsp-60 and gst-4. Further studies proved that the transcription factors HSF-1 and SKN-1/Nrf2 were implicated in hormetic stress response of the worms. Moreover, pretreatment of extract reduced the high glucose-mediated lipid accumulation by enhancing the expression of glyoxalase-1. It was also found that the aggregation of Parkinson’s related protein α-synuclein reduced in the transgenic strain NL5901 and extended its lifespan. Finally, our results concluded that the presences of hormetic dietary phytochemicals in tubers might drive the stress response in C. elegans via HSF-1 and SKN-1/Nrf2 signaling pathways.

STUDIES ON NUTRITIONAL PROFILE AND ANTIOXIDANT POTENTIAL OF DIFFERENT DIOSCOREA SP WITH PLECTRANTHUS ROTUNDIFOLIUS

Objective: Protection from oxidative damage to the tissues is provided by natural or synthetic antioxidants. Because of the multiple mechanisms of actions and presence of various phytochemicals, plant-based antioxidants are preferred. Dioscorea is well known as a traditional edible tuber. The present study was undertaken to explore and highlights the nutritional benefits and to evaluate the in vitro antioxidant and free radical scavenging capacity of ethanolic extract of three different underutilised Dioscorea species (D. alata, D. pentaphylla and D. oppositifolia) with a common cultivated crop, Plectranthus rotundifolius.Methods: Different processing methods are adopted to assess their influence on nutritive value and antioxidant properties. Tubers were studied for proximate composition using standard analytical methods. Mineral elements were analysed using ICP-MS (Inductively Coupled Plasma-Mass Spectrometer). Antioxidant potential of raw and processed samples was determined using a range of in vitro models.Results: The presence of essential minerals such as Na, K, Ca, P, Zn and Mn were observed. High radical scavenging activity was observed in the tubers of Dioscorea. Results indicated that phenolic compounds are the significant contributors to the antioxidant activity.Conclusion: Current study suggests that Dioscorea might be a promising natural antioxidant and could be very useful health food, as they enhance the antioxidant defence system. It also proposes that underutilized tubers can efficiently contribute to the nutritional requirement and food security.