Bioactive Molecules for Discriminating Robinia and Helianthus Honey: High-Performance Liquid Chromatography-Electron Spray Ionization-Mass Spectrometry Polyphenolic Profile and Physicochemical Determinations

Changes in health-promoting metabolites associated with high-altitude adaptation in honey

The levels of metabolites in honey are influenced by floral origin, production region, and bee species. However, how environmental factors affect honey quality remains unclear. Based on untargeted metabolomics and using UPLC Q-Orbitrap MS, we analyzed 3596 metabolites in 51 honey samples from Yunnan and Shennongjia. Comparative analysis revealed that geniposidic acid, kynurenic acid and caffieine accumulated at significantly different levels between Shennongjia and Yunnan honey. Based on cluster structure analysis, 36 Yunnan honey samples were divided into two distinct groups by altitude. Notably, quercetin, hyperoside, taxifolin, rutin, tryptophan, astragalin and phenylalanine were higher levels in high-altitude honey (>1700 m), whereas abscisic acid was higher levels in low-altitude honey (≤1700 m). Among these, significantly elevated levels of hyperoside, taxfolin, astragalin, and tryptophan were observed in honey collected from high-altitude areas in Shennongjia. Our findings highlight the effect of altitude on honey health-promoting components, providing valuable insights into honey quality.

Comparison of the Metabolomics of Different Dendrobium Species by UPLC-QTOF-MS

Dendrobium Sw. (family Orchidaceae) is a renowned edible and medicinal plant in China. Although widely cultivated and used, less research has been conducted on differential Dendrobium species. In this study, stems from seven distinct Dendrobium species were subjected to UPLC-QTOF-MS/MS analysis. A total of 242 metabolites were annotated, and multivariate statistical analysis was employed to explore the variance in the extracted metabolites across the various groups. The analysis demonstrated that D. nobile displays conspicuous differences from other species of Dendrobium. Specifically, D. nobile stands out from the remaining six taxa of Dendrobium based on 170 distinct metabolites, mainly terpene and flavonoid components, associated with cysteine and methionine metabolism, flavonoid biosynthesis, and galactose metabolism. It is believed that the variations between D. nobile and other Dendrobium species are mainly attributed to three metabolite synthesis pathways. By comparing the chemical composition of seven species of Dendrobium, this study identified the qualitative components of each species. D. nobile was found to differ significantly from other species, with higher levels of terpenoids, flavonoids, and other compounds that are for the cardiovascular field. By comparing the chemical composition of seven species of Dendrobium, these qualitative components have relevance for establishing quality standards for Dendrobium.

Phenolic compounds in Hungarian acacia, linden, milkweed and goldenrod honeys

Honey is a valuable source of nutrients, minerals and phenolic compounds. Phenolic acids and flavonoids are associated with health benefits of honey and can serve as markers for distinguishing honey types. This study aimed at determining the phenolic profile of four Hungarian unifloral honeys that were not analyzed previously. After verifying their botanical origin with melissopalynological analysis, total reducing capacity was determined with Folin-Ciocalteau method, and phenolic composition was analyzed with HPLC-DAD-MS. From the 25 phenolic substances examined, pinobanksin was the most abundant, followed by chrysin, p-hydroxybenzoic acid and galangin. Quercetin and p-syringaldehyde were detected only in acacia honey, which contained higher levels of chrysin and hesperetin compared to the other three honeys. Milkweed and linden honeys displayed higher levels of caffeic, chlorogenic, ferulic and p-coumaric acids compared to acacia and goldenrod honeys. Taxifolin may serve as a unique marker compound of milkweed honey. Goldenrod honey contained the highest level of syringic acid. Principal component analysis supported the indicator role of polyphenols in honey identification, discriminating clearly the four unifloral honeys. Our results suggest that phenolic profiles may be useful to find markers of honey's floral origin, but geographical origin can strongly influence the composition of characteristic compounds.

Chemical Profile, Antioxidant and Enzyme Inhibition Activities of Natural Saudi Sidr and Talh Honeys

Honey is used since ancient time as a food and to cure many diseases. The present study investigated the chemical constituents, antioxidant and enzyme inhibition activities of natural Saudi Sidr (SH) and Talh (TH) honeys. Beside entire honey samples, ethyl acetate, ethanol and water extracts were prepared. The total polyphenolic content of SH, TH and their extracts was in the range of 2.86-7.21 and 3.80-17.33 mg gallic acid equivalents/g, respectively and the total flavonoids content was in the range of 0.05-1.17 and 0.18-2.38 mg rutin equivalents/g, respectively. Out of the 53 standards analyzed by HPLC, 27 compounds were detected with highest number of compounds identified in the ethyl acetate extract of TH (45 %, 24/53) and SH (26 %, 14/53), respectively. Quinic acid was dominant compound identified in all honey samples with the highest content determined in TH ethanol extract (4454 μg/g). The majority of tested samples possessed considerable anti-radicals and reducing ions capacity with the ethyl acetate extract from TH exerted significantly (p<0.05) the highest activity. All honey samples did not show chelating iron metal property. Honey samples revealed variable enzyme inhibition activity with TH (entire and/or ethyl acetate extract) showed significantly (p<0.05) the highest acetylcholinesterase, butyrylcholinesterase, tyrosinase and α-amylase inhibition activity. In conclusion, ethyl acetate is the best solvent for extraction of bioactive molecules from the two honey types. Moreover, the dark-colored TH contained the highest number of molecules and consequently exerted the best antioxidant and enzyme inhibition activities in most assays.