Authors:A. K. Thakur, V. Jain, L. Hingorani, and K. S. Laddha
A simple, rapid, and specific reversed-phase HPLC method with DAD detection has been used for analysis of two flavonoids, quercetin and kaempferol, in Cissus quadrangularis Linn. The flavonoids were well resolved within 10 min, and quantification was achieved, on an endcapped C18 column at 370 nm with acetonitrile-phosphate buffer (pH 3.4, adjusted with glacial acetic acid) 60:40 (v/v) as isocratic mobile phase at a flow rate of 1.0 mL min−1. The method was validated for limit of detection, limit of quantification, linearity, precision, accuracy, and recovery. Linearity was demonstrated over the range 0.75 to 10 μg mL−1 for quercetin and 1.0 to 10 μg mL−1 for kaempferol with good correlation coefficients (r2 > 0.998). Detection limits were 0.075 and 0.10 μg mL−1 for quercetin and kaempferol respectively. Recovery was 98.0–105.3% for quercetin and 95.0–101.1% for kaempferol. The method was successfully applied to analysis of two flavonoids in four samples of Cissus quadrangularis Linn.
Authors:V. Jain, A. Thakur, G. Soman, and K. S. Laddha
A simple, rapid, and specific reversed-phase HPLC method has been developed for simultaneous analysis of withaferin-A and 6-gingerol in a polyherbal formulation containing Withania somnifera and Zingiber officinalis extracts. HPLC analysis was performed on a C18 column using a 40:60 (v/v) mixture of acetonitrile and water as isocratic mobile phase at a flow rate of 1.5 mL min−1. UV detection was at 227 nm for withaferin-A and 278 nm for 6-gingerol. The method was validated for accuracy, precision, linearity, specificity, and sensitivity in accordance with International Conference on Harmonization guidelines. Validation revealed the method is specific, accurate, precise, reliable and reproducible. Good linear correlation coefficients (r2 > 0.9996) were obtained for calibration plots in the ranges tested. Limits of detection were 0.2 and 0.4 μg and limits of quantification were 0.5 and 1.0 μg for withaferin-A and 6-gingerol, respectively. Intra and inter-day RSD of retention times and peak areas were less than 2.1%. Recovery was between 94.5 and 98.8% for withaferin-A and 94.2 and 102.4% for 6-gingerol. The established HPLC method is appropriate and the two markers are well resolved, enabling efficient quantitative analysis of withaferin-A and 6-gingerol. The method was successfully used for quantitative analysis of these two marker constituents in a marketed polyherbal formulation.
Authors:K.G. Mandal, K. Kannan, A.K. Thakur, D.K. Kundu, P.S. Brahmanand, and A. Kumar
Three-year (2007/2008–2009/2010) field experiment was conducted at the Directorate of Water Management Research Farm under Deras command in Odisha, India to assess the crop yield, irrigation water use efficiency (WUE), sustainable yield index (SYI), land utilization index (LUI) and changes in soil organic carbon (SOC) for dominant rice systems, viz. rice-maize-rice, rice-cowpea-rice, rice-sunflower-rice, rice-tomato-okra and rice-fallow-rice. Results revealed that crop yield, in terms of total system productivity (TSP) increased by 273, 113, 106 and 58% in rice-tomato-okra, rice-sunflower-rice, rice-maize-rice and rice-cowpea-rice, respectively, when compared to rice-fallow-rice. Irrigation WUE was 49–414% greater in rice-based diversified systems than the existing rice-fallow-rice (2.98 kg ha−1 mm−1). The SYI ranged from 0.65 to 0.75 indicating greater sustainability of the systems. Three crops in a sequence resulted in greater LUI and production efficiency compared to rice-fallow-rice. The gross economic return and benefit-cost ratio was in the order: rice-tomato-okra > rice-maize-rice > rice-sunflower-rice > rice-cowpea-rice > rice-fallow-rice. The SOC storage ranged from 40.55 Mg ha−1 in rice-fallow-rice to 46.23 Mg ha−1 in rice-maize-rice system. The other systems had also very close values of SOC storage with the rice-maize-rice system; there was a positive change of SOC (7.20 to 12.52 Mg ha−1) for every system, with highest in rice-maize-rice system and the lowest in rice-fallow-rice. It is concluded that the appropriate rice-based system would be rice-tomato-okra followed by rice-maize-rice, rice-sunflower-rice and rice-cowpea-rice. Rice-fallow-rice is not advisable because of its lower productivity, lower LUI and economic return.