Exploring the impact of polyphenolic compounds on the chromatic characteristics in flowers of Rhododendron arboreum Sm. collected from different altitudinal locations.

INTRODUCTION: Rhododendron arboreum Sm. flowers grow in the Himalayan region and have traditionally been used in beverages and food. These wild edible Himalayan flowers are known for their sweet-sour flavor and beautiful scarlet red color. The primary pigments responsible for the scarlet red color of these flowers are anthocyanins. OBJECTIVE: In the present study, we conducted chemo-profiling and elucidated the chromatic characteristics of R. arboreum flower petals growing in the wild in different altitudinal areas. METHODOLOGY: The content of anthocyanins, phenolics, and other flavonoids was determined in R. arboreum flower petals collected from 38 different locations in two provinces in India (Himachal Pradesh and Uttarakhand) to obtain a distinguishable chemical index. A UHPLC method has also been developed and validated for the quantitative analysis. Besides, the color characteristics of each collected floral sample were also analyzed. RESULTS: Chemometric analysis (principal component analysis [PCA] and heatmap analysis) revealed that floral samples collected from different altitudes exhibited similar chemical diversity, whereas statistical analysis (bivariate linear correlation) revealed a positive correlation between the color parameter a*/b* and cyanidin glycosides. Besides, non-targeted metabolomics analysis was carried out, which resulted in the tentative identification of 150 metabolites. CONCLUSION: The results revealed that there is a direct influence of accumulated anthocyanins to color parameter a*/b* values in the floral samples irrespective of altitude.

Effect of co-pigments on anthocyanins of Rhododendron arboreum and insights into interaction mechanism.

The impact of intermolecular copigmentation between five phenolic acids, two flavonoid and three amino acids with R. arboreum anthocyanins (ANS) and its isolated cyanidin-3-O-monoglycosides were investigated through experimental and theoretical approach. On addition of different copigments, phenolic acid induced strong hyperchromic (0.26-0.55 nm) and bathochromic shift (6.6-14.2 nm). The color intensity and stability of ANS with, storage at 4 °C & 25 °C, sunlight, oxidation and heat were evaluated by chromaticity, anthocyanin content, kinetic and structural simulation analysis. The strongest copigmentation reaction was observed with narningin (NA) and also showed high thermostability and highest half-life i.e. 3.39 h-1.24 h at 90-160 °C. The cyanidin-3-O-monoglycosides were analysed for their copigmentation effect and observations revealed that NA displayed best copigmentation effect to cyanidin-3-O-arabinoside (B) followed by cyanidin-3-O-galactoside (A), and cyanidin-3-O-rhamnoside (C). Additionally, structural simulation and steered molecular dynamics insights NA is the most favourable co-pigment involving π-π stacking and H-bonding.

Swertia chirayita: A comprehensive review on traditional uses, phytochemistry, quality assessment and pharmacology.

ETHNOPHARMACOLOGICAL RELEVANCE: Swertia chirayita (Roxb.) H. Karst. is a traditionally used, well-recognized medicinal plant of the family Gentianaceae with significant therapeutic potential. It has been traditionally used to cure various ailments such as fever, vomiting, jaundice, digestive disorders, heart diseases, diabetes, malaria, scorpion bite, and skin diseases. AIM OF REVIEW: The present review emphasized the traditional uses, phytochemistry, pharmacology, toxicology, chemical profiling, and structural identification of isolated compounds by analytical and spectroscopic techniques. This review demonstrates the possibility of advanced ethnopharmacological research. MATERIALS AND METHODS: The literature on S. chirayita was obtained from bibliographic databases like Web of Science, PubMed, Science-Direct, American Chemical Society (ACS), Google Scholar, and SciFinder. The compiled review is covered up until March 2022. RESULTS: Approximately, 123 specialized metabolites including xanthones, seco-iridoids, terpenoids, alkaloids, and flavonoids have been isolated and characterized from S. chirayita. The extract and isolated compounds exhibited a wide spectrum of pharmacological effects such as anti-inflammatory, antioxidant, antitumor, hepatoprotective, antiviral, antimalarial, and antibacterial offering scientific evidence for traditional claims of this medicinal plant. In addition, various analytical methods using HPTLC, UPLC, HPLC, LC-MS, and GC-MS have also been documented to determine the phytochemicals of S. chirayita. CONCLUSION: The current article provides information on traditional usage, phytochemistry, chemical profiling, structure elucidation, pharmacological efficacy, toxicity, and future prospects of S. chirayita. This plant has long been traditionally used in a variety of ways by indigenous people. Numerous phytoconstituents and several pharmacological activities have been reported in S. chirayita. However, there are still some scientific gaps such as identification of bioactive compounds, structure-activity relationship and mechanistic action of isolated bioactive compounds, development of effective analytical methods for comprehensive quality control, and safety profiles that need to be addressed.

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.

Polyphenolic composition and antioxidant potential of underutilized Himalayan wild edible berries by high-performance liquid chromatography coupled with electrospray ionization quadrupole time-of-flight mass spectrometry.

The Himalayan wild berries Myrica esculenta, Duchesnea indica, Prunus cerasoides, and Berberis lycium were studied for the first time for polyphenolic compositions using high-performance liquid chromatography/electrospray ionization tandem mass spectrometry. The chemical analysis of extracts resulted in the identification of 69 polyphenols, including 11 anthocyanins, 28 phenolic acids, 19 flavanoids, 10 ellagitannins, and 1 dihydrochalcone. The caffeoylquinic acids, quercetin, kaempferol, and cyanidin are the common moieties in studied wild berries. In addition, seven phenolic compounds, that is, gallic acid, vanillic acid, caffeic acid, rutin, ferulic acid, quercetin, and myricetin were quantified. Among anthocyanins, cyanidin-3-O-glucoside was the majorly quantified anthocyanin that ranged from 2.52 to 6.18% followed by delphinidin-3-O-glucoside (0.6%-5.53%). The samples were assessed for total phenolics, total anthocyanin content, and antioxidant potential. The results showed that M. esculenta and B. lycium had the highest total phenolic and anthocyanin content and exhibited promising antioxidant activity with IC50 of 32.100 ± 0.42 and 48.44 ± 0.46 µg/mL, respectively. Principal component analysis was able to clearly differentiate between four underutilized Himalayan wild edible berries. The wide variability of polyphenolic constituents supports the consumption of these berries not only to achieve the nutrient requirements among local people but also as promising sources of antioxidants for the food industry.

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.