Dioscorea Research Articles

Dioscorea Plants: A Genus Rich in Vital Nutra-pharmaceuticals-A Review.

Dioscorea species, known as “Yams,” belong to family Dioscoreaceae. This genus consists of more than 600 species distributed from Africa, Asia, the Caribbean’s South America, and the South Pacific islands. Their organoleptic properties make them the most widely used carbohydrate food and dietary supplements. The underground and/or aerial tubers represent valuable sources of proteins, fats, and vitamins for millions of people in West Africa. This review gives a shot of secondary metabolites of Dioscorea plants, including steroids, clerodane diterpenes, quinones, cyanidins, phenolics, diarylheptanoids, and nitrogen-containing compounds. This review collected the evidence on biological properties of description Dioscorea, including in-vitro and in-vivo studies. Dioscorea species contain promising bioactive molecules i.e. diosgenin that support their different biological properties, including antioxidant, hypoglycaemic, hypolipidemic, anti- antimicrobial, inflammatory, antiproliferative, androgenic, estrogenic, and contraceptive drugs. Indeed, besides its nutrient values, Dioscorea is a potential source of bioactive substances of interest in the prevention/treatment of several diseases, and thus represents a great challenge in developing countries. However, ethnomedicinal potential should be validated and further researches on pharmacological properties and phytochemical composition should be carried out. Particularly, doing some studies to convert the preclinical results to clinical efficacy should be guaranteed.Dioscorea, Food plant, Traditional use, Phytochemistry, Pharmacological activities

Studies on the Constituents of the <i>Dioscorea tokoro</i> Rhizome

Studies on the Constituents of the <i>Dioscorea tokoro</i> Rhizome

Enhancement of immune activities of Dioscorea japonica Thunberg in in vivo and ex vivo models

Enhancement of immune activities of Dioscorea japonica Thunberg in in vivo and ex vivo models

Suppressing Effects of Ethanol Extract from Dioscoreae Rhizoma on atope Dermatitis

Suppressing Effects of Ethanol Extract from Dioscoreae Rhizoma on atope Dermatitis

Evaluation of the impact of the Hyflex learning model

The HyFlex learning model adopted by Texas AM 2) synchronously; or 3) asynchronously via the adobe connect online-based meeting platform. This study focuses on evaluating the impact that HyFlex has regarding student achievements by assessing their performances from one quantitative course section offered in the program. Quantitative data was collected to examine multiple perspectives in regards to relationships between students' performance and their decision on attendance options in the same course. Findings include clarification on the preconception of quality assurance and efficacy on the HyFlex learning model, distance learning in general, as well as for quantitative courses deployed in a non-traditional online format. Future implications for research are discussed.

Ethnobotany and Nutritional Value of Two Domestic Yams (Dioscorea spp.) in Abaya Woreda, Southern Ethiopia

Background : From a food security perspective, yam is an important crop in the tropics and subtropics, where it produced both as a subsistence crop and on a commercial scale. This study aimed to assess the ethnobotanical knowledge and nutritional values of two domestic yams in Abaya Woreda, southern Ethiopia. Methods : Data were collected from sixty informants in three kebeles. From each kebele, the most productive top twenty farmers were selected by researchers based on their potential cultivation of yams with the assistance of Development Agency (DA). Ethnobotanical data were collected by semi-structured interviews and edible tubers and bulbils of these crops were collected for nutritional analysis at the Hawassa University Food Laboratory. The data were analyzed with descriptive statistics and Analysis of Variance (ANOVA) using MS-Excel and SPSS. Results : The results showed that farmers of Abaya Woreda have indigenous knowledge about forms of consumption, meal preferences, medicinal use, storage mechanisms and propagation systems of yams. Significant variation was observed in knowledge of edible plant parts and methods of tuber preservation for propagation in the study area. Similarly, the nutritional content of the crops showed variation in some of the measured parameters. For instance, Dioscorea bulbifera had higher carbohydrate content and total energy although it was the lower in moisture content. Conclusions : The present study has attempted to document ethnobotanical knowledge and nutritional values of two domestic Dioscorea species in Abaya Woreda, which should get attention by farmers, researchers, governmental and nongovernmental bodies in order to increase the food potential and indigenous knowledge in the study area. For the results presented here may help to conserve yam germplasm and create awareness about the importance of these crops to alleviate food insecurity. Key words : ethnobotany, nutritional value, yam, Abaya woreda.

Comparative evaluation of properties of paracetamol tablets formulated with three local starches as binders

This study was carried out to comparatively evaluate the tableting and release characteristics of paracetamol tablets prepared with three indigenous starches as binder. These parameters were compared with those tablets prepared with Maize starch BP as standard. Starches currently being used in pharmaceutical industry are largely imported into the country, hence there is the need to source for some indigenous starches whose binding properties would sufficiently ameliorate the brittle fracture tendency that has been a major problem in tableting. Starches from African bitter yam (Dioscorea dumetorium), cocoyam (Colocasia esculenta) and cassava (Mannihot utilissama) tubers were extracted and characterized with Maize starch BP as standard. Their true particle densities were determined with the specific gravity bottle method. Viscosities of the starch mucilage were also determined. The mucilage of each of these starches was used as binder at concentrations (1, 1.5, 2 and 2.5% w/w) per tablet in the formulation of paracetamol granules. The granules were compressed to tablets with and without a centre hole at varying compression loads (3, 4 and 5 arbitrary units). The tablets were flat faced with mean diameter of 12.1 ± 0.02 mm and mean thickness 4.1 ± 0.02 mm. The tablets’ tensile strength (T), brittle fracture index (BFI), packing fraction (Pf), disintegration time (DT) and dissolution profiles were determined. The centre hole in the tablet served as a model defect to represent void that are formed in the tablet during compression due to air entrapments. The results showed that there was no statistically significant difference in the physicochemical characteristics of the tablets whose granules were prepared with the 3 test starches and those prepared with the standard maize starch BP (p > 0.05). There was a general increase in the tablet viscosities as the mucilage concentration increased. Cassava starch mucilage was more viscous hence expected to impact more plasticity to the granules. Tablet tensile strength (T) increased with increase in the binder concentration but was more marked with tablets produced with cassava starch mucilage. At all m binder concentrations, cassava starch produced tablets with lowest BFI and highest Pf compared to the other starches including maize starch BP. Increase in compression load resulted in tablets with increase in T, BFI, Pf and DT. The increase in BFI is attributed to increase in die wall stress on the tablet at the point of ejection during compression. All the tablets released between 79.2 - 89.6% of the drug in 45 min. Although drug release was influenced by increase in binder concentration, the release rate was nevertheless significantly affected by the types of starch binders under investigation. The results permit the conclusion that the three (3) sourced indigenous starches (African bitter yam, cocoyam and cassava) could be substituted for maize starch BP as binder in the preparation of paracetamol tablets.Keywords: Cassava starch, African bitter yam starch, cocoyam starch, binder, tablet properties, paracetamol

DENTAL RADIOGRAPHIC PRESCRIBING PRACTICES: SURVEY OF DENTAL HYGIENISTS IN THE U.S.

Background Potential harm from ionizing radiation has led to the development of guidelines to protect patients and practitioners from unnecessary radiation exposure; however, these guidelines may or may not be followed in practice. Objective This study surveyed U.S. dental hygienists with regard to radiology policies in the workplace. Methods The survey, consisting of 62 knowledge and practice items regarding use of dental radiography, was based on the 2012 publication by the American Dental Association (ADA) and the U.S. Food and Drug Administration (FDA): “Dental Radiographic Examinations: Recommendations for Patient Selection & Limiting Radiation Exposure.” The study was granted exempt status by the Texas AM for adolescent patients, corporate and general dental practices preferred to make bitewing images every 12 months, whereas educational institutions preferred to make bitewing images every 18 months (P Conclusions The findings of this study suggest that some dental practices are not strictly following the ADA/FDA guidelines with regard to frequency of radiographic exposures.

Complete chloroplast genome sequences of Dioscorea: Characterization, genomic resources, and phylogenetic analyses.

Dioscorea L., the largest genus of the family Dioscoreaceae with over 600 species, is not only an important food but also a medicinal plant. The identification and classification of Dioscorea L. is a rather difficult task. In this study, we sequenced five Dioscorea chloroplast genomes, and analyzed with four other chloroplast genomes of Dioscorea species from GenBank. The Dioscorea chloroplast genomes displayed the typical quadripartite structure of angiosperms, which consisted of a pair of inverted repeats separated by a large single-copy region, and a small single-copy region. The location and distribution of repeat sequences and microsatellites were determined, and the rapidly evolving chloroplast genome regions (trnK-trnQ, trnS-trnG, trnC-petN, trnE-trnT, petG-trnW-trnP, ndhF, trnL-rpl32, and ycf1) were detected. Phylogenetic relationships of Dioscorea inferred from chloroplast genomes obtained high support even in shortest internodes. Thus, chloroplast genome sequences provide potential molecular markers and genomic resources for phylogeny and species identification.

Predicting the potential global distribution of diosgenin-contained Dioscorea species

BackgroundDiosgenin, mainly extracted from wild diosgenin-contained Dioscorea species, is a well-known starting material of steroidal and contraceptive drugs. However, due to large market demand and increasingly ecological damage, wild Dioscorea species resources available have been gradually declining. Therefore, identification of new potential ecological distribution of diosgenin-contained Dioscorea species is necessary for diosgenin production.MethodsIn this study, a large occurrence dataset (1808 data points) of diosgenin-contained Dioscorea species was obtained from Eastern Asia, Southern North America and Southern Africa. Along with the data for six critical environmental parameters and one soil factor, Geographic Information System for Global Medicinal Plant was applied to predict the potential suitable distribution of Dioscorea species.ResultsThe results showed that the potential distribution of these Dioscorea species covered a wide field, and that new ecological suitability areas were mainly distributed in the central region of South America, the southern part of the European and coastal region of Oceania. Jackknife test indicated that annual precipitation and annual mean radiation were the important climatic factors controlling the distribution of Dioscorea species.ConclusionsThe suitable areas and critical climatic factors will serve as a useful guide for diosgenin-contained Dioscorea species conservation and cultivation in ecological suitable areas.

Yam physic-chemical parameters assessment and its bread sensory attributes for corporate agribusiness boosting

A research work entitled: “Yam physico-chemical parameters assessment and its bread sensory attributes.” was carried out in the laboratory of INES-Ruhengeri for adding value to local yam called Dioscorea spp. The main objective was to assess physico-chemical parameters of fresh yam tubers and sensory attributes of produced bread from yam fermented flour. A sample size of 10kg of each Dioscorea variety as fresh crude yam tubers was brought from Musanze market to INES laboratory for chemical analysis, fermentation and bread processing. Physico-chemical parameters analyzed in fresh crude yam tubers included moisture content, pH, nutrient content and sensory evaluation of yam bread. The results showed that fresh crude yam tubers moisture content ranged from 75 to 77%. This moisture content is favoring yam tubers spoilage and there is a need to process fresh yams into bread for adding value. The yielded fermented yam flour ranged from 18 to 20% from crude yam tubers. The dried and fermented yam flour moisture content was around 13% and met the standards, while pH was around neutral (from 6.66 to 6.72) leading to tubers deterioration. The flour had a dark-brown color from enzymatic browning occurring during fermentation process. According to Hedonic scale, the overall acceptability of yam breads was good with mean sensory scores ranging from 7.33 to 7.83 over 9 emitted by trained panelists. Fermented yam flour with Aspergillus niger and Aspergillus oryzae followed by Saccharomyces cerevisiae used in yam bread making was considered nutritious by panelists. Hence, the processed yam bread is a good source of nutrients including carbohydrates, protein, fat, minerals and probiotics. The use of fermented yam flour in bread making is advantageous due to increased nutritional value and reduced rate of staling. Adding value to fresh yam tubers can lead to income generation and enhanced shelf life of new developed yam bread. It is therefore recommended to promote yam cultivation and processing of tubers at industrial level for food security and sustainability.

BUILDING A NATIONAL ALLIANCE OF ACADEMIC CENTERS FOR RESEARCH ON HEALTHY AGING

AbstractThe purpose of this symposium is to initiate a dialog that explores opportunities to develop a national alliance of academic centers for research on healthy aging. Our goals are to create opportunities to train the next generation of researchers to address a range of healthy aging research topics, support efforts to engage diverse communities in applied translational research, design and implement cross-disciplinary interventions, develop networks to ensure rapid and effective response to emergent funding priorities, and leverage skills and experience of alliance members to help standardize concepts, measures, and methodologies. This session will include presentations by Directors of four academic centers for research on healthy aging: University of Washington (UW) de Tornyay Center for Healthy Aging; Texas AM University of Illinois, Chicago (UIC) Center for Research on Health and Aging; and University of South Carolina (USC) Arnold School of Public Health Office of Aging. The Centers represent various geographical areas, disciplines, initiatives, and funding streams. Each of the presentations will include common components of the centers such as mission, scope of activities, and key accomplishments. Additionally, each center will focus on reporting out one type of activity: workforce capacity (UW), multilevel evaluations of evidence-based programming (TAMU), dissemination of evidence-based physical activity programs (UIC), and partner-engaged research and education for cognitive health (USC). The session will provide a model of collaboration among investigators for the promotion of aging research and training. The discussant will provide context and strategies for successful alliance-building.

The parasitism of Persian jird by immature stages of Hyalomma asiaticum (Acari: Ixodidae) and its identification using molecular approaches in Iran

In the present study, occurrence of Hyalomma asiaticum on wild rodents was explored. Rodents were trapped using Sherman traps. The tick specimens were collected by forceps from the rodents. Overall, one larva and 59 nymphs of immature ticks were collected on 23 Meriones persicus from three different locations in western Iran. A 408 bp length fragment of nuclear 5.8S /internal transcribed spacer 2 ( ITS2 ) genes was amplified in 60 examined tick specimens using PCR, of which one sample was sequenced, successfully. The BLAST results showed 99% similarity between a new haplotype from this study and two sequences of H. asiaticum from GenBank and. Therefore, we conclude that immature stages of H. asiaticum live on M. persicus and/ or their burrows. This finding helps us to better understand tick's ecology and control tick borne diseases.

Guinea yam (Dioscorea spp., Dioscoreaceae) wild relatives identified using whole plastome phylogenetic analyses

AbstractThe genus Dioscorea (Dioscoreaceae) contains several economically important species for human consumption, medical and pharmaceutical uses. The phylogeny of this genus is not yet fully resolved. As a result, the relationships between cultivated yams and their wild relatives are not well understood and this negatively affects the understanding of the evolution of cultivated yams. Here, we reconstructed the phylogenetic relationships of the main African cultivated species with all West African species in order to better circumscribe the crop wild relatives of African yams. Complete plastomes of 57 individuals representing all 17 known Dioscorea species from West Africa were reconstructed. Tree topologies generated using maximum parsimony and maximum likelihood approaches were highly congruent. Six monophyletic groups were obtained. All the species were distinct except within the cultivated clade, where it was not possible to separate the two main cultivated species (D. cayenensis, D. rotundata) from their closest West African wild relatives (D. abyssinica, D. praehensilis, D. sagittifolia). Dioscorea baya formed a monophyletic group closely related to the cultivated clade. We therefore suggest it is included within the yam crop–wild relative complex.

Morphological and functional seed traits of the wild medicinal plant Dioscorea strydomiana, the most threatened yam in the world.

Morphological and functional seed traits have important roles in characterising the species regeneration niche and help to understand the reproductive biology of rare and threatened plants, which can thus support appropriate plant conservation measures. Seed morphometric and dispersal kinetics of the critically endangered Dioscorea strydomiana were measured and compared with those of four other Dioscorea species, and seed germination response under constant temperatures (5-35°C) was compared with that of the congeneric and widespread D.sylvatica. Seed mass of D.strydomiana (ca. 14mg) was twice that of D.sylvatica, but similar to or smaller than the other species examined. Seeds of D.strydomiana have the lowest speed of descent and lowest variability in most of the morphological traits considered, suggesting lower phenotypic plasticity but higher variance in the wing-loading value. Seeds of D.strydomiana reached maximum germination at 15°C (ca. 47%), which decreased slightly to ca. 37% at 25°C and was completely inhibited at 35°C. D.sylvatica seeds started to germinate at 10°C (ca. 3%), reached 75-80% germination at 15-20°C and maximum (ca. 90%) at 25-30°C. Base temperatures for germination (Tb ) were 9.3 and 5.7°C, for D.strydomiana and D.sylvatica, respectively. Due to the higher germination percentages of D.sylvatica, ceiling and optimum temperatures could also be modelled for this species, suggesting higher sensitivity to high temperature for seeds of D.strydomiana. The detected poor seed lot quality of D.strydomiana suggests difficulties in reproduction from seed, highlighting the need for further investigation and conservation actions for this threatened yam species.

Dioscorea longipedicellata (Dioscoreaceae), a new species from the Indian subcontinent

A new species of Dioscorea, viz., D. longipedicellata is described and illustrated based on collections from northeast India and northwest Bangladesh. The new species is closely allied to D. kamoonensis and D. pentaphylla. D. longipedicellata can be diagnosed by its glabrous stem, glabrous membranous lamina, pedicellate male flowers, funnel-shaped, fleshy prominent pedicels, glabrous bract situated at the base of pedicel directly on rachis and membranous, glabrous tepals.

PROTECTIVE EFFECT OF DIOSGENIN AGAINST CARBON TETRACHLORIDE AND CISPLATIN INDUCED HEPATOTOXICITY IN RATS

Background: Activation of hepatic stellate cells (HSC) plays central role in the development of liver fibrosis. In HSC activation, the transforming growth factor-1 (TGF-1) is considered to be the main stimuli factor. Diosgenin are the steroidal saponin and found in Trigonella foenum graecum Linn (Fenugreek) and some other species of Dioscorea. Diosgenin attenuates HSC activation by inhibiting transforming growth factor. Aim: In present study an attempt was made to explore the effect of diosgenin on liver fibrosis. Methods: Liver fibrosis was induced in rats by carbon tetrachloride (CCl4) 1 ml/kg intraperitoneally twice a week for 28 days and cisplatin 3mg/kg intraperitoneally at 0, 1, 3 week for 4 weeks. The extent of liver fibrosis was assessed by measuring the weight of liver and levels of total bilirubin (TBL), hydroxyproline (HP) and serum enzymes due to deposition of extracellular matrix (ECM). Results: The administration of diosgenin reduced the liver weight of CCl4 and cisplatin treated animals and reduced the TBL, HP level and serum enzymes significantly and inhibited liver fibrosis induced by CCl4 and cisplatin. Conclusion: The result obtained in the present investigation, Diosgenin treatment exerted significant hepatoprotective effect in animals by inhibiting ECM deposition and HSCs activation.

Keanekaragaman Dioscorea spp dan habitatnya di Kabupaten Kudus, Jawa Tengah Diversity and habitat of Dioscorea spp in Kudus, Central Java

Dioscorea spp (Yam) is one of the potential local food producers. It has advantage of high species diversity, containing high carbonhydrate and easy to grow. The aim of this research is to determine the variants of Dioscorea spp, examine the structure and composition of trees around Dioscorea spp habitat and determine the enviromental factors of Dioscorea spp habitat. The research was carried out in May-June 2017. The sampling technique was using exploration and quadratic method by plotting the trees into 5 squares (10 m x 10 m) with diameter of stem more than 10 cm. The name of each species, number of individuals and stem diameter measurement of each plot were recorded. The data of diversity Dioscorea spp and environmental factors were analyzed by sort of descruptive set and the trees was analyzed by vegetation analysis. The results showed that 4 species of Dioscorea spp. There are D. hispida, D. bulbifera, D. alata and D. esculenta. D. alata has 3 variants called uwi ireng, uwi ungu and uwi bangkulit. D. esculenta has 2 variants called gembili bebek and gembili terpong. The trees around Dioscorea spp obtained 21 species with the most important index is banana (Musa paradisiaca) and sengon (Albizia chinensis). The environmental factors were indicated the appropiate growth of Dioscorea spp. Key words: Dioscorea spp, local food stuffs and variant types

Ethnopharmacological Potential and Medicinal Uses of Miracle Herb Dioscorea spp.

Dioscorea a well-known source of Diosgenin-steroid raw material, is one of the oldest tuber crop cultivated or harvested from wild in the tropical region throughout the world and make up one of the chief food items for a number of tribal groups. In India there are about 50 species of dioscorea, mainly found in North-East region which is rich in tropical root and tuber crops. Dioscorea produces rhizomes or bulbils, which are having rich medicinal and economic value. The rhizomes are used for the treatment of different diseases like cardiovascular system disorders, central nervous system disorders, disease of bones and joint metabolic disorder, disgestive disorders, sore throat for struma, diarrhea, irritability, abdominal pain, dysfunctional changes in the female reproductive system, skin diseases, oncology and immune deficiency and autoimmune diseases, anti-diabetes, neuroprotectiveused, decrease oxidative stress and many more disordered conditions. Diosgenin is a precursor for the chemical synthesis of drug like steroids and has a great importance for pharmaceutical industry. Dioscorea contains various bioactive chemical substances like diosgenin, corticosterone, and sigmasterol, which are of great market value. The current study is to appraise the medicinal properties, phytochemicals, and pharmacological activities of Dioscorea.

Late Holocene Palaeoenvironment of TSE Dura, a Later Stone Age (Lsa) Rock Shelter, North-Central Nigeria

Abstract Palynological and archaeobotanical analyses were conducted on excavated sediments from Tse Dura, a Later Stone Age rock shelter in north-central Nigeria with the aim of reconstructing the environment conditions at the site within the last millennium. From 933 ± 29 BP to 802 ± 29 BP, the environment alternated between Guinea savanna with dry conditions, and secondary and riverine forests with humid conditions. During these periods of environmental fluctuations, the LSA populations engaged in the management of economic plants the most significant of which included Dioscorea spp. Pennisetum glaucum and Elaeis guineensis, and exploited wild plants such as Pavetta crassipes, Sarcocephalus latifolius and Lophira cf. lanceolata for dietary and ethnomedicinal purposes. Around 310 ± 30 BP cal, the environment became very wet after which it was succeeded by a drier period. It was during this period that Sorghum bicolor became prominent, and the environment attained its current status dominated by Guinea savanna elements and secondary forests.