Search

Herein, a micro‐solid‐phase extraction (μSPE) method was developed using a pipette tip for rutin extraction, employing activated hollow carbon nanospheres (HCNSs) as the sorbent. Characterization of the activated carbon nanospheres through TGA, FTIR, and SEM analysis confirmed the success of the activation process. The study demonstrated the efficacy of PT‐μSPE in rutin extraction under pH 2 conditions with a standard concentration of 2 mg·L−1. The optimal mass of HCNSs was found to be 2 mg, and a loading volume of 500 μL resulted in the maximum recovery of rutin. Propan‐2‐ol was the best elution solvent with 15 aspirating/dispensing cycles. The correlation of determination (R2) for the calibration curve was found to be 0.9991, and the LOD and LOQ values were 0.604 and 1.830 mg·L−1, respectively. The applicability of the method was demonstrated by extracting rutin from a complex Moringa oleifera leaf extract with the relative standard deviation (RSD) of 3.26%, thereby validating this method as feasible for the extraction of useful bioactive compounds from complex plant samples. [ABSTRACT FROM AUTHOR]

Enterolactone, coumaric acid and vitexin are polyphenolic compounds present in a variety of fruits, vegetables, cereals and plants. These bioactive compounds are in high demand due to their antioxidant property in various tissues and organs. The purpose of this study was to develop a simultaneous extraction method, an aqueous two‐phase extraction (ATPE) method, that would enable the extraction of these compounds from Hypoxis iridifolia. This environmentally friendly extraction method only applied water and ethanol as extraction solvents for these analytes from the plant matrix. After phase separation, the analytes were salted‐out from the aqueous phase into the organic phase with the aid of a chaotrope (NaCl) or kosmotrope (Na2CO3). Thereafter, the analytes were withdrawn by a micro‐pipette for analysis on the high‐performance liquid chromatography–photodiode array detector. Optimization was conducted using a central composite design, where three parameters were examined which involved percentage ethanol, centrifugation time and salt type. Generally, the optimized conditions for extraction were an ethanol percentage of 100% and a centrifugation time of 10 min, which yielded concentrations of 2942, 23,823 and 8881 mg kg−1 for enterolactone, vitexin and coumaric acid, respectively, in the presence of a kosmotrope. The optimized conditions of extraction in the presence of chaotrope were an ethanol percentage of 66% and a centrifugation time of 10 min with concentrations of 6727, 20,833 and 8618 mg kg−1 for enterolactone, vitexin and coumaric acid, respectively. The ATPE method involving Na2CO3 was a better extractant of all the compounds studied relative to that of NaCl. The superior extraction capability of Na2CO3 in ATPE could serve as a prototype for the development of efficient extraction methods to meet the high demand for medicinal compounds derived from natural products. [ABSTRACT FROM AUTHOR]

The biomass Solanum mauritianum (S. mauritianum) is an invasive weed specie; however, it is a source of medicinally important metabolites, as reported in literature, such as solasonine and solamargine. The study was directed at the optimization of microwave and aqueous two-phase-based extraction techniques which involved microwave-assisted extraction (MAE), aqueous two-phase extraction followed by microwave-assisted extraction (ATPE + MAE), and the "one-pot" microwave-assisted aqueous two-phase extraction (MA-ATPE) for extraction of solasonine and solamargine from leaves of S. mauritianum which was evaluated. The microwave-assisted extraction of solasonine and solamargine yielded optimums at 5.00 min, microwave power of 270 W, and solid/liquid of 0.1 g L−1 at an ethanol concentration of 60%. Application of a two-stage extraction (MAE + ATPE) in CaO-dried alcohol resulted in decreased amounts of solasonine and solamargine extracted. The best yields of solasonine and solamargine were achieved in the MA-ATPE method. Extraction of solamargine and solasonine using Na2CO3 in CaO-dried ethanol during MA-ATPE was approximately threefold and twofold greater than that of MAE + ATPE, respectively. Furthermore, extraction of solamargine and solasonine using NaCl in CaO-dried ethanol during MA-ATPE was approximately twofold greater than that of MAE + ATPE. The synergy of microwaves and salting-out in the "one-pot" MA-ATPE technique was shown to be a contributing factor for enhanced extraction of solamargine and solasonine from leaves of S. mauritianum. Application of this time- and energy-efficient extraction method could potentially be expanded for enrichment of medicinally important compounds from biomass of other medicinal plants. [ABSTRACT FROM AUTHOR]

Rationale: Although mass spectrometry (MS) is a powerful tool in structural elucidation of unknown flavonoids based on their unique fragmentation patterns, proposing the correct fragmentation mechanism is still a challenge from tandem mass spectrometry data only. In recent years, computational tools such as molecular networking and MS2LDA have played a major role in the identification of structurally related compounds through an in‐depth survey of their fragmentation patterns. Methods: Therefore, in this study, three viscutin molecules in Viscum combreticola Engl. crude extracts were characterised using ultra‐high‐performance liquid chromatography‐quadrupole‐time‐of‐flight tandem mass spectrometry and MS2LDA, a computational tool. Ion‐trap mass spectrometry and density functional theoretical modelling were used as confirmatory tools to rationalise the unique fragmentation patterns observed for these molecules. Results: Here, MS2LDA revealed the presence of a unique Mass2Motif in all the three viscutin molecules at m/z 137, which was confirmed to be a 1,3A− RDA (retro‐Diels‐Alder) fragmentation product using liquid chromatography‐ion‐trap mass spectrometry and density functional theoretical modelling. Moreover, MS2LDA proved to be useful in differentiating this spectral feature that was specific to viscutin molecules in the presence of other isobaric ions at m/z 137 occurring in compounds in other molecular families. Conclusion: Therefore, the results of the current study showed that computational tools such as MS2LDA are essential in uncovering some gas‐phase fragmentation reactions of molecules in MS and that theoretical modelling is a powerful tool in rationalising these reactions in metabolite identification. [ABSTRACT FROM AUTHOR]