Introduction Hyperuricemia is the key risk factor for gout, in which the elevated uric acid is attributed to the oxidation of hypoxanthine and xanthine to uric acid by xanthine oxidase (XO). Adverse effects of the current treatments lead to an urgent need for safer and more effective alternative from natural resources. Objective To compare the metabolite profile of Chrysanthemum morifolium flower fraction with that of its detannified fraction in relation to XO inhibitory activity using a rapid and effective metabolomics approach. Methods Proton nuclear magnetic resonance (1H‐NMR)‐based metabolomics approach coupled with multivariate data analysis was utilised to characterise the XO inhibitors related to the antioxidant properties, total phenolic, and total flavonoid contents of the C. morifolium dried flowers. Results The highest XO inhibitory activity, 1,1‐diphenyl‐2‐picryl hydrazyl (DPPH) radical scavenging activity, total phenolic and flavonoid content with strong positive correlation between them were observed in the ethyl acetate (EtOAc) fraction. Detannified EtOAc showed higher XO inhibitory activity than non‐detannified EtOAc fraction. A total of 17 metabolites were tentatively identified, of which three namely kaempferol, 4‐hydroxybenzoic acid and apigenin, could be suggested to be responsible for the strong XO inhibitory activity. Additive interaction between 4‐hydroxybenzoic acid and apigenin (or kaempferol) in XO inhibition was demonstrated in the interaction assay conducted. Conclusion Chrysanthemum morifolium dried flower‐part could be further explored as a natural XO inhibitor for its anti‐hyperuricemic potential. Metabolomics approach served as an effective classification of plant metabolites responsible for XO inhibitory activity, and demonstrated that multiple active compounds can work additively in giving combined inhibitory effects.

Xanthine oxidase (XO) plays an important role in purine degradation in humans. The study aimed to determine the XO inhibitory potential of Chrysanthemum morifolium dried flower ethyl acetate sub-fractions and its anti-hyperuricemic effect in rat models. Bioassay-guided fractionation based on XO inhibitory assay was employed to obtain bioactive fractions and sub-fractions. In vitro cytotoxicity and cellular antioxidant capacity of the sub-fraction and its mode of XO inhibition were also investigated. The anti-hyperuricemic effect of the bioactive sub-fraction was investigated using rat models via oral consumption, and followed by an XO mRNA gene expression study. The compounds in the bioactive sub-fractions were identified putatively using HPLC-Q-TOF-MS/MS. Ethyl acetate (EtOAc) fraction exhibited the highest XO inhibition among the fractions. It was further fractionated into 15 sub-fractions. F10 exhibited high XO inhibitory activity, cellular pro-proliferative effect, and intracellular antioxidant activity among the sub-fractions tested. This sub-fraction was non-cytotoxic at 0.1–10 µg/mL, and very effective in lowering serum and urine uric acid level in rat models upon oral consumption. A total of 26 known compounds were identified and seven unknown compounds were detected via HPLC-Q-TOF–MS/MS analysis. The possible mechanisms contributing to the anti-hyperuricemic effect were suggested to be the non-competitive inhibition of XO enzyme, XO gene expression down-regulation, and the enhancement of uric acid excretion.

This study was conducted in order to identify the presence of four synthetic phenolic antioxidants (SPAs): propyl gallate (PG), tert-butylhydroquinone (TBHQ), butylated hydroxyanisole (BHA), and butylated hydroxytoluene (BHT) in various food stuffs that are commonly consumed in Malaysia. The identification method was optimized and validated before it was applied to the analyses of eighty three food samples which include chewing gum, chili sauce, cereal-based snack food, noodles, potato snack, cereal breakfast, oat, biscuit, cookie, coffee, junk food, seaweed, nut, chocolate, apple juice, orange juice and blackcurrant juice. Twenty nine food samples contained SPAs either singly or in combination. The chromatography conditions such as elution method, flow rate and wavelength were optimized. Good linearity ranges (1–300 mgL–1) were found for all the four phenolic antioxidants. RSD for repeatability and reproducibility ranged from 0.15–0.84% for both precision analyses. LOD and LOQ ranged from 0.02–0.67 and 0.06–2.03 mgL–1, respectively. Recoveries of the four SPAs ranged from 80.4 to 119.0% when selected food items spiked at 10, 50, and 100 mgL–1.

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In the past, the Cratoxylum genus has often been utilized as traditional medicines, culinary ingredients, health supplements, as well as manufacturing materials. This flowering plant genus belongs to the family Hypericaceae and is classified into six species: Cratoxylum arborescens, Cratoxylum cochinchinense, Cratoxylum formosum, Cratoxylum glaucum, Cratoxylum maingayi, and Cratoxylum sumatranum. The Cratoxylum genus is native to Asia as a traditional medicinal plant. It is currently being translated into conventional therapeutics as a preventive agent for diabetes mellitus and cardiovascular diseases. The phytochemical analysis and pharmacological investigations on the Cratoxylum species have unveiled the wide spectrum of phytoconstituents, including xanthones, triterpenoids, flavonoids, and phenolic compounds. These compounds are attributed to their significant pharmacological effects, such as antibacterial, antifungal, antioxidant, antimalarial, anti-gastric ulcer, anti-HIV-1 reverse transcriptase, antidiabetic, and anticancer activities. These research findings have strengthened the foundation of the Cratoxylum genus as a traditional medicinal plant to be further developed and applied as selective therapeutic drugs for various ailments. This paper discusses the Cratoxylum genus regarding its traditional uses, phytochemical compounds, and pharmacological properties.