ABSTRACT
Eleven compounds were isolated and purified from Sorghum vulgare root extract, through column chromatography over silica gel, MCI gel, and preparative HPLC. Their structures were established by MS, 1 D NMR and 2 D NMR data as sorgholide A(1), β-sitosterol(2), stigmastero(3), daucosterol(4), 4-methoxycinnamic acid(5), taxiphyllin(6), chlorogenic acid(7), p-hydroxybenzaldehyde(8), succini acid(9), trans-p-hydroxycinnamic acid(10), obtusalin(11). Compounds 4,5 and 9-11 were reported from this species for the first time, and compound 1 is the first 24 ring dimeric double lactonol glycoside formed by reverse polymerization of p-hydroxyphenylacetate glucoside, named sorgholide A.
Subject(s)
Cardiac Glycosides , Glucosides , Glycosides , Phenols , SorghumABSTRACT
An oxalate oxidase was purified to apparent homogeneity from the leaves of 10-days old seedlings of forage Sorghum (Sorghum vulgare var. KH-105). The enzyme had a Mr of 124 kDa with two identical subunits, an optimum pH of 4.5, optimum temperature of 37°C and activation energy (Ea) of 2.0338 Kcal/mol. The rate of reaction was linear up to 7 min. Km value for oxalate was 0.22 mM. The enzyme was stimulated by Cu2+ and inhibited by EDTA, NaCN, diethyldithiocarbamate, na2SO4, but unaffected by NaCl at 0.1 mM concentration. Although the enzyme was stimulated by flavin mononucleotide (FMN) and flavin adenine dinucleotide (FAD), UV and visible spectra of the enzyme did not match with that of a flavoprotein. The positive reaction of the enzyme with orcinol-H2SO4 reagent indicated its glycoprotein nature. The superiority of the purified enzyme over earlier reported oxalate oxidases for determination of urinary oxalate has been demonstrated.
ABSTRACT
Role of alternative respiration, a thermogenic pathway, was evaluated in temperature rise of water stressed plants. Transpiration rate, plant temperature and respiratory dynamics were monitored in field grown irrigated and unirrigated sorghum (Sorghum vulgare Pers.) hybrid CSH 6 and pearl millet (Pennirelum typhoider (Burm. f.) Stapt and Hubbard) var. J 104 for 22 days. Transpiration rate of irrigated plants was always higher than the unirrigated plants. But the plant temperature and the alternative respiration activity of irrigated plants was always lower than unirrigated plants. The reduction in transpiration rate of unirrigated pearl millet was more as compared to unirrigated sorghum. Nonetheless, alternative respiration activity was higher in unirrigated sorghum as compared to unirrigated pearl millet. Temperature of unirrigated sorghum plants increased by 10·4°C during 22 days and it was 8·0°C higher than irrigated sorghum at day 22. Stressed pearl millet showed an increase of 3·9°C during 22 days and it was 2·9°C higher than the irrigated pearl millet at day 22. It is suggested that the heat released because of the alternative respiration activity also contributes towards temperature rise of water stressed plants.
ABSTRACT
Activity of key nitrogen assimilating enzymes was studied in developing grains of high-lysine opaque sorghum P-721 and normal sorghum CSV-5. The higher percentage of protein in opaque sorghum was mainly due to lower starch content since protein per grain was less than in CSV-5. During grain development, albufn and globulin decreased while prolafne and glutelin increased. Prolafne content in CSV-5 was higher than in opaque sorghum. Average nitrate reductase activity in flag and long leaf were similar in both the varieties. The nitrate reductase activity decreased during grain development. Glutamate dehydrogenase activity was higher during early development and lower at later stages in opaque sorghum than in CSV-5. Glutamate oxaloacetate transaminase activity was higher and glutamine synthetase lower in opaque sorghum than in CSV-5 grains during development. Glutamate synthase activity was higher in opaque sorghum up to day 20 and lower thereafter than in CSV-5. It is suggested that reduced activities of glutamine synthetase as well as glutamate synthase in opaque sorghum as compared to CSV-5 during later stages of development may restrict protein accumulation in the former.