Nilesh K. Rai

Role of LIBS in Elemental Analysis of Psidium guajava Responsible for Glycemic Potential

Abstract The present study deals with the detection of elements responsible for glycemic potential of ripe and unripe fruit peel aqueous extracts of Psidium guajava (P. guajava). Treatment with the aqueous extract of unripe fruit peel showed a significant fall of 17.5% (p<0.001) in blood glucose levels (BGLs) of normal rats during fasting blood glucose (FBG) test with a dose of 400 mg/kg bw. In sub‐diabetic rats, a fall of 19.8% (p<0.001) was observed with the same dose during a glucose tolerance test (GTT). The significant fall observed in FBG, post prandial glucose (PPG) and urine sugar levels of severely diabetic rats was 20.7%, 17.5% (p<0.05), and 66.6% (p<0.01), respectively. On the contrary, the effect of ripe fruit peel aqueous extract showed a regular rise of 24.4% (p<0.01) in BGL of normal rats and of 90.0% (p<0.001) in sub‐diabetic rats. Laser Induced Breakdown Spectroscopy (LIBS) has been used for the identification of elements responsible for the glycemic potential of fruit peel aqueous extracts of P. guajava. Concentration of Mg was found higher in unripe fruit peel aqueous extract than in the ripe fruit peel aqueous extract whereas the concentration of K was found lower in the extract of unripe fruit peel than in the extract of ripe fruit peel. Thus, the LIBS results help in defining the role of Mg and K in diabetes management. However, the concentrations of other minerals, like Na, N, O, and C, are nearly the same in both of the extracts.

Detection sensitivity of laser-induced breakdown spectroscopy for Cr II in liquid samples

The performance of laser-induced breakdown spectroscopy (LIBS) has been evaluated for detection of toxic metals such as Cr in water. Pure aqueous solutions (unitary matrix) with variable Cr concentration were used to construct calibration curves and to estimate the LIBS limit of detection (LOD). The calibration curves for Cr in a binary matrix (Cr plus Cd) and a tertiary matrix (Cr plus Cd and Co) were used to evaluate the matrix effect on the LOD. The LOD for Cr was found to be 1.1, 1.5, and 2.0 ppm (parts in 10(6)) in a unitary, binary, and tertiary matrix, respectively. Once calibrated, the system was utilized for the detection and quantification of the Cr in tannery wastewater collected from different locations in the industrial area of Kanpur, India, where Cr concentrations were determined to be far higher than the U.S. Environmental Protection Agency safe drinking water limit of 0.05 ppm.

LIBS-based detection of antioxidant elements: a new strategy.

The present study deals with the scientific evaluation of antioxidant potential of aqueous extract of Trichosanthes dioica fruits on diabetes-induced oxidative stress of diabetic rats. The most effective dose of mg/kg bw of fruit aqueous extract was given orally to diabetic rats for 30 days. Different oxidative stress parameters were analyzed in various tissues of control and treated diabetic rats. The observed elevated level of lipid peroxidation (LPO) comes down significantly (p < 0.05) and decreased activities of antioxidant enzymes such as catalase (CAT), superoxide dismutase (SOD), glutathione peroxidase (GPx), and glutathione-S-transferase (GST) got increased (p < 0.05) significantly of diabetic rats on extract treatment. Laser-Induced Breakdown Spectroscopy (LIBS) has been used as an analytical tool to detect major and minor elements like Mg, Fe, Na, K, Zn, Ca, H, O, C, and N present in the extract. The higher concentration of Ca(2+), Mg(2+), and Fe(2+), as reflected by their intensities are responsible for antioxidant potential of T. dioica.