Calligonum polygonoides Linnaeus Extract: HPLC‐EC and Total Antioxidant Capacity Evaluation

Calligonum polygonoides L. as Novel Source of Bioactive Compounds in Hot Arid Regions: Evaluation of Phytochemical Composition and Antioxidant Activity

Calligonum polygonoides L. (Phog) is an endemic perennial herb that is highly resistant to all type of abiotic stresses and dominant biomass as well as phytochemicals producer in its natural habitat of the “Thar Desert” of Rajasthan, India. The present study was conducted to evaluate the effect of extreme environmental conditions on the phenolic, flavonoids, tannin content, and total antioxidant activities of C. polygonoides foliage harvested during different months. It exhibited a significant variation in the content of phenolic compounds, flavonoids, tannins, and antioxidant activity with harvesting time and all parameters are positively correlated to each other. The highest phenolic compounds and antioxidant activity was observed during severe winter and summer months, when monthly average environmental temperature was lowest and highest of the year, respectively. On the basis of the results, two harvests of C. polygonoides foliage during June and December are advised to maximize the phenolic compound production with highest antioxidant activity. These results demonstrate C. polygonoides, which is a dominant biomass producer under the harsh climatic conditions, can be an important source for the development of the functional foods rich in antioxidants in hot arid regions.

Multidirectional insights into the phytochemical, biological, and multivariate analysis of the famine food plant (Calligonum polygonoides L).: A novel source of bioactive phytocompounds

Calligonum polygonoides L. also known as famine food plant, is normally consumed in times of food scarcity in India and Pakistan and also used traditionally in the management of common diseases. The present design aims to provide an insight into the medicinal potential of four solvent extracts of C. polygonoides via an assessment of its phytochemical profile, antioxidant and enzyme inhibitory potential. Phytochemical composition was estimated by deducing total bioactive constituents, UHPLC-MS secondary metabolites profile, and HPLC phenolic quantification. Antioxidant potential was determined via six methods (radical scavenging (DPPH and ABTS), reducing power (FRAP and CUPRAC), phosphomolybdenum total antioxidant capacity and metal chelation activity). Enzyme inhibitory potential was assessed against clinical enzymes (acetylcholinesterase -AChE, butyrylcholinesterase -BChE, tyrosinase, and α-amylase). The highest amounts of phenolic contents were found in chloroform extract (76.59 mg GAE/g extract) which may be attributed to its higher radical scavenging, reducing power and tyrosinase inhibition potential. The n-butanol extract containing the maximum amount of flavonoids (55.84 mg RE/g extract) exhibited highest metal chelating capacity. Similarly, the n-hexane extract was found to be most active against AChE (4.65 mg GALAE/g extract), BChE (6.59 mg GALAE/g extract), and α-amylase (0.70 mmol ACAE/g extract) enzymes. Secondary metabolite assessment of the crude methanol extract as determined by UHPLC-MS analysis revealed the presence of 24 (negative ionization mode) and 15 (positive ionization mode) secondary metabolites, with most of them belonging to phenolic, flavonoids, terpene, and alkaloid groups. Moreover, gallic acid and naringenin were the main phenolics quantified by HPLC-PDA analysis in all the tested extracts (except n-butanol extract). PCA statistical analysis was also conducted to establish any possible relationship amongst bioactive contents and biological activities. Overall, the C. polygonoides extracts could be further considered to isolate bioactive enzyme inhibitory and antioxidant natural phytocompounds.

Natural phenolic antioxidants electrochemistry: Towards a new food science methodology

Natural phenolic compounds are abundant in the vegetable kingdom, occurring mainly as secondary metabolites in a wide variety of chemical structures. Around 10,000 different plant phenolic derivatives have been isolated and identified. This review provides an exhaustive overview concerning the electron transfer reactions in natural polyphenols, from the point of view of their in vitro antioxidant and/or pro-oxidant mode of action, as well as their identification in highly complex matrixes, for example, fruits, vegetables, wine, food supplements, relevant for food quality control, nutrition, and health research. The accurate assessment of polyphenols' redox behavior is essential, and the application of the electrochemical methods in routine quality control of natural products and foods, where the polyphenols antioxidant activity needs to be quantified in vitro, is of the utmost importance. The phenol moiety oxidation pathways and the effect of substituents and experimental conditions on their electrochemical behavior will be reviewed. The fundamental principles concerning the redox behavior of natural polyphenols, specifically flavonoids and other benzopyran derivatives, phenolic acids and ester derivatives, quinones, lignins, tannins, lignans, essential oils, stilbenes, curcuminoids, and chalcones, will be described. The final sections will focus on the electroanalysis of phenolic antioxidants in natural products and the electroanalytical evaluation of in vitro total antioxidant capacity.