Quantitative determination of specialised metabolites in different parts of Juglans regia Linn. and Carya illinoinensis (Wangenh.) K. Koch by using UHPLC-DAD-QTOF-MS/MS.

INTRODUCTION: Juglans regia Linn. and Carya illinoinensis (Wangenh.) K. Koch are nut-producing plant species of the Juglandaceae family. Bioactive compounds like naphthoquinones, tetralones, and diarylheptanoids are dominant in these species. OBJECTIVE: The study aimed to develop and validate a fast and sensitive analytical method by ultrahigh-performance liquid chromatography diode array detection mass spectrometry (UHPLC-DAD-MS) for quantification and identification of bioactive compounds in fruit pericarps and leaves of J. regia and C. illinoinensis collected from two different states of north India. METHODOLOGY: The dried pericarps of J. regia and C. illinoinensis (500 mg) were extracted with ethyl acetate-methanol (50:50 v/v, 20 mL, 50°C, 30 min) by ultrasonication and analysed by ultrahigh-performance liquid chromatography diode array detection quadrupole time-of-flight tandem mass spectrometry (UHPLC-DAD-QTOF-MS/MS) for qualitative and quantitative examination of phytoconstituents. The method was validated according to International Council for Harmonisation of Technical Requirements for Pharmaceuticals for Human use (ICH) guidelines for linearity, precision, accuracy, limit of detection (LOD), and limit of quantification (LOQ). RESULTS: Here, we report the quantification of dihydrophaseic acid (1), 4,5-dihydroxytetralone (2), 4,8-dihydroxytetralone (3), 5,8-dihydroxy-3-methoxytetralone (4), and juglanin A (5) in the pericarps and leaves of J. regia and C. illinoinensis. Furthermore, using the hyphenated analytical method, a total of 62 compounds were tentatively characterised in different samples. The principal component analysis (PCA) showed diversity between the analysed sample's composition. Also, the study evaluated the variation of bioactive compounds among different parts of J. regia and C. illinoinensis collected from different regions of northern India by UHPLC-DAD-QTOF-MS/MS. CONCLUSION: The developed method is simple, rapid, and selective for the identification and characterisation of bioactive molecules.

Identification and quantification of anthocyanins, flavonoids, and phenolic acids in flowers of Rhododendron arboreum and evaluation of their antioxidant potential.

The current study aimed to investigate the anthocyanins, non-anthocyanins (flavonoids and phenolic acids), and free radicals scavenging potential in the flowers of Rhododendron arboreum using ultra high performance liquid chromatography with ion mobility quadrupole time of flight tandem mass spectrometry. A total of 25 constituents including nine anthocyanins, six phenolic acids, and ten flavonoids were identified in the flower extract. The major anthocyanins identified were cyanidin-3-O-ß-galactoside (1), cyanidin-3-O-α-arabinoside (4), and cyanidin-3-O-rhamnoside (8), while quercetin glycosides were the main identified flavonoids in R. arboreum flowers. Additionally, ultra high performance liquid chromatography methods were developed and validated for the quantification of nine compounds (anthocyanins, flavonoid glycosides, and phenolic acids); five of them were quantified using internal standards. The extracts were analyzed for total phenolics (123.6 mg GAE/g), anthocyanin content (1.76% w/w), and evaluated for antioxidant properties against 2,2-diphenyl-1-picrylhydrazyl radical (IC50 : 102.06 and 96.92 µg/mL) and 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) radical cation (112.25 and 45.59 µM TE/g) assays. The profiling of R. arboreum for anthocyanins is reported for the first time. The findings suggest that the flowers are a promising source of bioactive constituents and could be used as functional food, antioxidants, and nutraceuticals.

Copigmentation and UPLC-ESI-MS/MS of anthocyanin in Ipomoea nil as potential source of food colorant.

Anthocyanins are good alternative to synthetic dyes for food, pharmaceutical and nutraceutical industries. Owing to their wide occurrence in plant kingdom, an UPLC-ESI-MS/MS method was used to identify and quantify the constituents in flowers of Ipomoea nil. The qualitative evaluation of I. nil results in the characterisation of acylated and non-acylated anthocyanins. Besides characterisation, the total phenolic contents in different fractions of I. nil were found to be 49.69 ± 1.74 and 331.54 ± 1.14 mg GAE/g, respectively. The total anthocyanins content was also determined by spectrophotometer and found to be 5.89 mg/100g of cyanidin-3-O-glucoside equivalent. The antioxidant activity of different fraction of I. nil was evaluated by different assays (DPPH●, ABTS●+ and FRAP). In the direction of natural colour stability, we had studied different stabilising agents/copigments and were found to provide stability up to 140 °C. The extracted anthocyanins were evaluated for acute oral toxicity studies and observed to be non-toxic and may direct the use of I. nil for human consumption.

Two undescribed diarylheptanoids from green husk of Carya illinoinensis as acetylcholinesterase inhibitors.

Two undescribed diarylheptanoids, 3-(R)-acetyl-1-(3',4'-dihydroxyphenyl)-7-(4''-hydroxy-3'' -methoxyphenyl)-heptane (1) and 11-Hydroxy-1,17-epoxy-7-(2-hydroxylphenyl)-13-(16-methoxyphenyl)-heptane (2) together with known compounds, namely, 11-Oxo-1,17-epoxy-7-(2-hydroxylphenyl)-13-(16-methoxyphenyl)-heptane (3) 3,4,5-Trihydroxytetralone (4) 4,8- Dihydroxytetralone (5), 4,5-Dihydroxytetralone (6), 5,8-Dihydroxy-3-methoxytetralone (7) were isolated from ethyl acetate extract of the green husk of Carya illinoinensis. The structures of compounds were established on the basis of IR, 1H NMR, 13C NMR, DEPT, HSQC, HMBC, COSY spectroscopic and ESI-MS analysis. The isolated compounds were evaluated for AChE (acetylcholinesterase inhibition) and observed that compound 5 was potent inhibitor with IC50 of 101.48 ± 4.00 µg/mL.

Amelioration of cognitive deficit in zebrafish by an undescribed anthraquinone from Juglans regia L.: An in-silico, in-vitro and in-vivo approach.

An undescribed anthraquinone assigned as 1-Hydroxy-5,5-dimethyl-5,6,7,8-tetrahydro-9,10-anthraquinone (compound 1) was isolated from ethylacetate extract of Juglans regia L. The structure of the compound was established on the basis of 1D, 2D NMR (HSQC, HMBC, COSY), ESI-QTOF-MS/MS spectroscopy. The molecular docking studies of compound 1 indicated similar molecular interactions as that of co-crystalized inhibitor. Compound 1 showed hydrogen bonds with residues PHE295, GLY121, π-σ interactions with TYR 341, π-π interactions with HIS 447 residues, and π-alkyl with TRP86 and TYR 337. On the basis of in-silico interaction studies of compound 1 with proteins, it was tested using acetylcholinesterase inhibition assay, acrylamide-induced neurotoxicity test of zebrafish larva, and scopolamine-induced cognitive deficit model of adult zebrafish. The compound 1 showed potent acetylcholinesterase inhibition activity, prevented acrylamide-induced neurotoxicity and improved learning and memory functions in T-maze test. The results established compound 1 to be a potential neuroprotective natural product for amelioration of cognitive impairment.

Dammarane triterpenoid glycosides in Bacopa monnieri: A review on chemical diversity and bioactivity.

Bacopa monnieri (L.) is a reputed medicinal herb in traditional system of medicine of India, where it is used as nervine tonic to sharpen intellect and memory. This review discusses chemical characterization of dammarane triterpenoid glycosides which are well accepted for improvement in memory and for potential pharmacological activities. In addition, this review provides information on the chemical composition of specialized metabolites of B. monnieri and in the formulations by different analytical techniques. This comprehensive review covers literature up to 2019 with an emphasis on structural characterization of dammarane triterpenoid glycosides by spectroscopic techniques, chemical composition by analytical methods and pharmacological activities.