LC–MS/MS Method for Quantification of Liquiritigenin in Rat Plasma: Application to Pharmacokinetic Study of Liquiritin

Characterization of constituents by UPLC-MS and the influence of extraction methods of the seeds of Vernonia anthelmintica willd.: extraction, characterization, antioxidant and enzyme modulatory activities

Vernonia anthelmintica Willd (VA) is a popular medicinal plant used in local and traditional medicine to manage various disorders. In order to explore the phytochemical profile, antioxidant and enzyme modulatory activities of extracts prepared from the seeds of VA, different extraction methodologies, including modern (accelerated-ASE, ultrasound-UAE, and tissue smashing-TSE extractions) and traditional (maceration and Soxhlet) extractions, were employed and their effects on the activities of the extracts were investigated. The chemical compounds of the extracts were qualitatively analyzed by ultra-high-pressure liquid chromatography-tandem mass spectrometry (UPLC-Orbitrap-MS) technique. Among them, 11 compounds were undoubtedly identified by comparison with reference substance, while 13 compounds were tentatively identified by comparison with literature data, including 8 phenolic acids, 14 flavonoids and 2 esters were identified in the extracts. Additionally, the quantitative analysis found that ASE showed the highest extraction efficiency. The antioxidant activity was determined in vitro via six standard assays. Two key enzymes related to the diseases of vitiligo (tyrosinase) and type II diabetes (α-glucosidase) were adopted to assess the activity of VA extracts against them. All extracts showed potent antioxidant ability with a predominance for that obtained by ASE, which corroborated with the high phenolic (22.62 ± 0.23 mg gallic acid equivalent (GAE)/g extract) and flavonoid contents (68.85 ± 0.25 mg rutin equivalent (RE)/g extract). The extracts obtained by ASE, UAE and SE could increase the tyrosinase activity and all the extracts displayed remarkable inhibitory activity against α-glucosidase. This study demonstrated that the VA extracts obtained by novel extraction techniques such as ASE, could be considered as a positive candidate to be utilized by the food and medical industries, not only for obtaining bioactive compounds to be used as natural antioxidants, but possibly also for its health benefits for therapeutic bio-product development.

Characterization of the global metabolic profile of liquiritin in rat plasma, urine, bile and feces based on UHPLC-FT-ICR MS

Liquiritin is a major flavonoid in Radix Glycyrrhizae and it has been reported to possess various pharmacological activities. In the present work, a strategy based on an ultra high performance liquid chromatography combined with Fourier transform ion cyclotron resonance mass spectrometry (UHPLC-FT-ICR MS) method was proposed to systematically characterize the in vivo metabolites of liquiritin for the first time. After oral administration of liquiritin to rats in a single dose of 120 mg kg⁻¹, the rat plasma, urine, feces and bile samples were collected and used to discover metabolites. As a result, besides the parent drug, a total of 76 metabolites (6 phase I and 70 phase II metabolites) of liquiritin were detected and tentatively identified. It was indicated that the metabolic pathways of liquiritin in rats included oxidation, reduction, deglycosylation, isomerization, methylation, glucuronidation and sulfation. In summary, the results could provide valuable information regarding the metabolism of liquiritin in rats, which could contribute to a better understanding of its action mechanism.

Liquiritin is a major flavonoid in Radix Glycyrrhizae and it has been reported to possess various pharmacological activities.