Pebrellin

Post-Distillation By-Products of Aromatic Plants from Lamiaceae Family as Rich Sources of Antioxidants and Enzyme Inhibitors.[Pubmed:36671072]

Antioxidants (Basel). 2023 Jan 16;12(1):210.

There is currently no use for the vast quantities of post-distillation by-products, such as spent plant materials and residual waters, produced by the essential oil (EO) industry of aromatic herbs. In this study, the EOs of three Lamiaceae species (thyme, oregano, and basil) and their total, spent, and residual water extracts were phytochemically characterized and biologically assessed. The collected information was put through a series of analyses, including principal component analysis, heatmap analysis, and Pearson correlation analysis. Concerning the EOs, 58 volatile compounds were present in thyme (e.g., p-cymene, thymol), 44 compounds in oregano (e.g., thymol, carvacrol), and 67 compounds in basil (e.g., eucalyptol, linalool, estragole, (E)-methyl cinnamate). The LC-HRMS/MS analysis of the total, spent, and residual water extracts showed the presence of 31 compounds in thyme (e.g., quercetin-O-hexoside, Pebrellin, eriodictyol), 31 compounds in oregano (e.g., rosmarinic acid, apigenin, kaempferol, salvianolic acids I, B, and E), and 25 compounds in basil (e.g., fertaric acid, cichoric acid, caftaric acid, salvianolic acid A). The EOs of the three Lamiaceae species showed the highest metal-reducing properties (up to 1792.32 mg TE/g in the CUPRAC assay), whereas the spent extracts of oregano and basil displayed very high radical-scavenging properties (up to 266.59 mg TE/g in DPPH assay). All extracts exhibited anti-acetylcholinesterase (up to 3.29 mg GALAE/g), anti-tyrosinase (up to 70.00 mg KAE/g), anti-amylase (up to 0.66 mmol ACAE/g), and anti-glucosidase (up to 1.22 mmol ACAE/g) effects. Thus, the present research demonstrated that both the raw extracts (EOs and total extracts) and the post-distillation by-products (spent material and residual water extracts) are rich in bioactive metabolites with antioxidant and enzyme inhibitory properties.

Metabolomics and biochemical analyses revealed metabolites important for the antioxidant properties of purple glutinous rice.[Pubmed:35490525]

Food Chem. 2022 Sep 30;389:133080.

Glutinous rice can be applied to many fields including brewing industry, medicine, cosmetics and food processing. However, we know very little about the basic metabolite information of glutinous rice. In this study, we identified the phenol and flavonoid metabolites in purple glutinous rice and white glutinous rice, and elucidated the relationship between metabolites and total antioxidant capacity. The results demonstrated that flavonoids contents, oligomeric proanthocyanidin contents and total antioxidant capacity of purple glutinous rice were significantly higher than those of white glutinous rice. We identified 390 differential metabolites between the purple glutinous rice and white glutinous rice by LC-MS metabolomics. Correlation analysis results showed that flavonoid and phenol metabolites contents were strongly correlated with total antioxidant capacity. This study further clarified that the pantothenic acid, Pebrellin, l-glutamic acid, eupatilin, diosmin, and diosmetin could be used as candidate metabolite markers for antioxidant capacity screening in glutinous rice grains.

Trixis angustifolia hexanic extract displays synergistic antibacterial activity against M. tuberculosis.[Pubmed:29277116]

Nat Prod Res. 2019 May;33(10):1477-1481.

A phytochemical and antibacterial study of Trixis angustifolia, a species endemic to Mexico, was performed allowing the isolation of six flavones. The minimal inhibitory concentration (MIC) of the hexanic extract, against Mycobacterium tuberculosis H37Rv was 25 mug/mL. The hexanic extract caused a significant inhibition of intracellular mycobacterial growth at 12.5 mug/mL. The biodirected assay of hexane extract enabled the detection of an active fraction (AF) against M. tuberculosis (MIC = 12.5 mug/mL), and a major flavone 1 (Pebrellin) with no antimycobacterial activity (MIC > 200 mug/mL). A subsequent combination antimicrobial assay showed a synergistic antimycobacterial effect of AF in combination with Pebrellin; the results of the synergistic activity suggest that the antimycobacterial activity found in T. angustifolia is due to the combined action of diverse metabolites present in the plant.

Differentiation of mint (Mentha haplocalyx Briq.) from different regions in China using gas and liquid chromatography.[Pubmed:25431171]

J Sep Sci. 2015 Feb;38(3):402-9.

In this study, complex substances such as Mint (Mentha haplocalyx Briq.) samples from different growing regions in China were analyzed for phenolic compounds by high-performance liquid chromatography with diode array detection and for the volatile aroma compounds by gas chromatography with mass spectrometry. Chemometrics methods, e.g. principal component analysis, back-propagation artificial neural networks, and partial least squares discriminant analysis, were applied to resolve complex chromatographic profiles of Mint samples. A total of 49 aroma components and 23 phenolic compounds were identified in 79 Mint samples. Principal component analysis score plots from gas chromatography with mass spectrometry and high-performance liquid chromatography with diode array detection data sets showed a clear distinction among Mint from three different regions in China. Classification results showed that satisfactory performance of prediction ability for back-propagation artificial neural networks and partial least squares discriminant analysis. The major compounds that contributed to the discrimination were chlorogenic acid, unknown 3, kaempherol 7-O-rutinoside, salvianolic acid L, hesperidin, diosmetin, unknown 6 and Pebrellin in Mint according to regression coefficients of the partial least squares discriminant analysis model. This study indicated that the proposed strategy could provide a simple and rapid technique to distinguish clearly complex profiles from samples such as Mint.