Antioxidant activity, antibacterial potential and characterization of active fraction of Dioscorea pentaphylla L. tuber extract collected from Similipal Biosphere Reserve, Odisha, India

ABSTRACT Dioscorea pentaphylla L., a wild tuber is used both as food and medicines among different ethnic groups of Similipal Biosphere Reserve, India. Tubers are used against skin infections. In order to establish and confirm tribal claims, methanol extract was subjected to fractionation. The active fraction (DP1) was subsequently used for further purification and NMR (Nuclear magnetic resonance) characterization. The phytochemical analysis revealed the presence of saponin groups. The antibacterial activity of DP1 was done against selected bacterial strains (Salmonella typhi, Shigella flexneri, Streptococcus pyogenes, Streptococcus mutans and Vibrio cholerae) using DD (disc diffusion), AWD (agar well diffusion) and broth dilution assay. The activity was compared with antibiotics Penicillin and Kanamycin. It was observed that DP1 showed significant inhibitory activity against the tested bacteria. The characterization of DP1 through NMR analysis and presence of proton in carbon position at C-3, C-19, C-18, C-21 and C-27 was same as the known compound "Diosgenin". Therefore, isolated compound was confirmed to be Diosgenin. The study for the first time showed that, diosgenin present in D. pentaphylla tuber was responsible for antibacterial and antioxidant potential. Present study highlights the importance of Dioscorea species as sources of diverse secondary metabolites for the isolation of active compound(s).

A Case of Life-Threatening Acute Kidney Injury with Toxic Encephalopathy Caused by Dioscorea quinqueloba

Some herbal medications induce acute kidney injury. The acute kidney injuries caused by herbal medications are mild and commonly treated by palliative care. A 51-years-old man who drank the juice squeezed from the raw tubers of Dioscorea quinqueloba (D. quinqueloba) was admitted with nausea, vomiting and chilling. He developed a seizure with decreased level of consciousness. He was diagnosed with acute kidney injury, which was cured by continuous venovenous hemodialfiltration. Non-detoxified D. quinqueloba can cause severe acute kidney injury with toxic encephalopathy. It is critical to inform possible adverse effects of the medicinal herbs and to implement more strict regulation of these products.

Uso de distintos tratamientos de desinfección en el cultivo in vitro de Dioscorea alata L clon caraqueño / Use of distinct disinfection treatments in the in vitro culture of Dioscorea alata L clone caraqueño

El cultivo in vitro, como técnica, consiste en cultivar asépticamente una porción aislada de la planta bajo condiciones de ambiente controlado, para que las células expresen su potencial intrínseco e inducido. El presente trabajo tuvo como objetivo determinar el efecto de diferentes concentraciones y tiempos de inmersión en hipoclorito de sodio en el establecimiento in vitro de explantes primarios de ñame (Dioscorea alata L) clon caraqueño. Las variantes de desinfección consistieron en la utilización de diferentes concentraciones de hipoclorito de sodio (1,5; 2 y 2,5%) durante distintos tiempos de inmersión (10; 20 y 30 min). A los 7 días se evaluó el porcentaje de contaminación de bacterias y hongos respectivamente, y a los 40 días el número de nudos de novo, la longitud del vástago, el número de hojas, y el porcentaje de explantes establecidos y necrosados. Se aplicó un diseño experimental completamente aleatorizado con análisis de varianza bifactorial y clasificación simple. Se realizó la prueba de comparación de medias de Tukey para un nivel de significación del 5%. Los resultados obtenidos arrojaron que el tratamiento de desinfección de segmentos uninodales de ñame con hipoclorito de sodio al 1,5% durante un tiempo de inmersión 30 min es el de mayor efectividad para el establecimiento in vitro de explantes primarios del ñame (D alata L. clon caraqueño con altos porcentajes de supervivencia en condiciones ex vitro.

The in vitro culture technique consists of aseptically culturing an isolated plant portion in controlled environmental conditions for the cells to express their intrinsic and induced potential. This work was aimed at determining the effect of different sodium hypochlorite concentrations and immersion times on in vitro establishment of yam (Dioscorea alata L) “caraqueño” clone primary explants. Disinfection varied by using different sodium hypochlorite concentrations (1.5%, 2% and 2.5%) during different immersion times (10, 20 and 30 min). Bacterial and fungal contamination percentages were evaluated after 7 days and de novo bud number, shoot length, leaf number, explant establishment and necrosis percentages were determined after 40 days. A totally randomised experimental design was applied, having one- and two-factor variance analysis; the Tukey test was used for comparing means at 5% significance level. The results showed that the most appropriate disinfection treatment for uninodal yam (D alata L) segments used 1.5% sodium hypochlorite during 30 min immersion; this was most effective for the in vitro establishment of yam (D alata L) clone “caraqueño” primary explants, having high survival percentage in ex vitro conditions.