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Objective: The objective of this study was to develop a simple and sensitive ultra-performance liquid chromatography (UPLC) method for determination of nitrate and nitrite in plant extracts and biological samples.Methods: Nitrate was analyzed directly by injecting the filtered sample into UPLC and monitoring the chromatogram at 222 nm whereas, for nitrite analysis, the samples were derivatized using Griess reagent, and chromatogram was monitored at 520 nm. The method was validated for accuracy and precision.Results: The calibration curve was obtained in the range of 0.05–500 μg/ml for nitrate and 5–3200 ng/ml for nitrite which were extremely linear, where both correlation coefficients were >0.9990. Accuracy of the method was found as 99.87% and 100.24% for nitrate and nitrite, respectively. High degree of precision and repeatability was obtained since coefficient of variation values were <2.1%. Among the three commonly used anticoagulants, i.e., K2EDTA, Li-Heparin, and sodium citrate, Li-Heparin did not show any interference with nitrate or nitrite analysis.Conclusion: Results clearly indicate the sensitivity and suitability of the developed method for estimation of nitrate and nitrite in plant extracts and biological samples. Our findings also indicate that Li-Heparin does not interfere with analysis and thus can be used as anticoagulant while collecting blood.

Objective: Development and validation of a High-Performance Liquid Chromatography (HPLC) method for the simultaneous estimation of 6-, 8-, 10-Gingerols and 6-Shogaol in ginger extract using authentic standards. Methods: The chromatographic separation was achieved by using a C18 column and a mobile phase composed of acetonitrile, ortho-phospohoric acid in water and methanol. The proposed method was validated in terms of the analytical parameters such as specificity, accuracy, precision, linearity, range, the limit of detection (LOD) and limit of quantification (LOQ) according to ICH guidelines. Results: Linear calibration curves were obtained over concentration ranges of 10-250 µg/ml for 6-, 8-, 10-gingerols and 6-shogaol with determination coefficients more than 0.99 for each analyte. Intra and inter-day precisions of the method were found to be below 2% for each analyte, with relative standard deviation (% RSD) values in the range of 0.47 to 1.55% for 6-gingerol, 0.44 to 1.51% for 8-gingerol, 0.24 to 1.90% for 10-gingerol and 0.25 to 1.67% for 6-shogaol. The percentage recovery of gingerols and shogaol was obtained with an average of 99.53%, 99.97%, 100.13% and 100.53% respectively, which was well within acceptance range. Conclusion: Simple, accurate, precise and rapid HPLC method was developed for the simultaneous analysis of 6-, 8-, 10-gingerols and 6-shogaol and validated in accordance with ICH guidelines. The developed method was found to be suitable for the standardization of herbal extracts and polyherbal formulations for the content of 6-, 8-, 10-gingerols and 6-shogaol.

Nitrates and nitrites occur naturally in the environment. They are important plant nutrients and vegetables account for about 70-90% of the total estimated dietary nitrate intake. Nitrate plays an important role in the nutrition and function of plants. Vegetables rich diet has been described beneficial for longevity and overall health of humans. The positive effects of vegetables may be attributed, in part, to inorganic nitrate present in green leafy vegetables. The nitrate and nitrite level in vegetables varies significantly from type of vegetables, demographic area and season. Nitrate and nitrite content of vegetables has been reviewed and an attempt was made to establish nitrate to nitrite ratio present in vegetables.