Nephroprotective potential ofQuercus infectoriagalls against experimentally induced diabetic nephropathy in rats through inhibition of renal oxidative stress and TGF-β

LC-MS/MS-based Targeted Metabolomic Profiling of Aqueous and Hydro-alcoholic Extracts of Pistacia integerrima Linn., Quercus infectoria Olivier and Terminalia chebula Retz

Background

Pistacia integerrima (PI) galls, being rich in polyphenolic compounds, owing to its high restorative worth and restricted assets and exorbitant utilization lead to the overexploitation of the species and availability issues. It is expected to categorise under the red list of threatened taxa. Ayurveda text Bhaishajaya Ratnavali mentioned Quercus infectoria (QI) as ‘pratinidhi’ or substitute of PI and Yogaratnakara (abhavvarga) text reference indicated Terminalia chebula (TC) having the same therapeutic character as in PI. Hence, this study was focused on the comparative quantification of major polyphenolic compounds in aqueous and hydro-alcoholic extracts of PI, QI and TC by liquid chromatography and tandem mass spectroscopy (LC-MS/MS).

Objectives

The LC-MS/MS method was used for the determination of polyphenolic compounds in aqueous and hydro-alcoholic extracts of PI, QI and TC.

Materials and Methods

The LC-MS/MS method was developed for the quantification of targeted polyphenolic compounds and validated in terms of linearity, accuracy, precision, limit of detection and limit of quantification. Analysis performed by LC-MS/MS 6460 C triple quad coupled with Agilent HPLC. The chromatographic separation was performed on the RP C18 column with gradient elution.

Results

The developed method of LC-MS/MS was used for the quantitative estimation of gallic acid, corilagin acid, caffeic acid, syringic acid, rutin hydrate, ellagic acid, quercetin and morin hydrate in PI, QI and TC. As per method validation parameters, calibration plots were found to be linear, accurate, precise and specific for LC-MS/MS. The calibration plot exhibited an excellent coefficient of determination ( R2 ≥ 0.99), and extraction recovery was found 96.20%–103.71%. Gallic acid and ellagic acid are the most abundant compound among eight targeted polyphenolics in all extracts.

Conclusion

The finding of LC-MS/MS analysis of polyphenolic compounds in aqueous and hydro-alcoholic extracts indicates that PI, QI and TC are having phytochemical similarities up to an extent in polyphenolic compounds as a secondary metabolite; however, a firmer opinion can be formed after a comparative efficacy study and the evaluation of all three extracts.

Impact of Quercus infectoria Galls Extract on Thyroid Gland and Testicular Functions in Diabetic Rats

Diabetes mellitus has been reported to be accompanied by thyroid and testicular dysfunctions. The objective of this study was to investigate the effect of Quercus infectoria galls (QIg) extract on the thyroid gland and testicular functions in diabetic rats. Sixteen rats were randomly divided into four equal groups, consisting of normal control, diabetic untreated control, diabetic treated with oral administration of 500 mg/kg BW and 1000 mg/kg BW, respectively for 15 days. Serum blood glucose, thyroid stimulating hormone (TSH), triiodothyronine (T3), thyroxine (T4), testosterone (T), and luteinizing hormone (LH) were assessed. At the end of the experimental period, the rats were euthanized for histopathological analysis of thyroid gland and testis. Furthermore, immunohistochemistry was used to assess the expression of thyroid transcription factor-1 (TTF-1) in the thyroid gland of rats. The significant increase in serum blood glucose level in diabetic rats (DC) was markedly decreased by treatment with QIg extract (500 mg and 100 mg/kg BW) almost to the normal level. The reduced thyroid hormones, both the T3 and T4 were significantly recovered after 15 days of treatment with QIg extract (500 mg and 100 mg/kg BW). Whereas serum concentration of testosterone was significantly reduced in diabetic rats with QIg extract (500 mg and 100 mg/kg BW) treatment. Histopathological analysis of diabetic rats showed a wide range of morphological alterations in thyroid gland and testicular structures, which were almost completely, restored back to normal by treatment of rats with QIg extract. Furthermore, results showed overexpression of TTF-1 in the thyroid gland of diabetic rats, which was recovered back to normal expression after 15 days of treatment with QIg extract. These findings may provide new insights into the potential role of QIg extract as a promising therapeutic agent against diabetic complications in thyroid gland and testicular functions.