Lancerin

2-Phenyl-4,4,5,5-tetramethylimidazoline-1-oxyl 3-oxide Radical (PTIO*) Trapping Activity and Mechanisms of 16 Phenolic Xanthones.[Pubmed:29997352]

Molecules. 2018 Jul 11;23(7). pii: molecules23071692.

This study used the 2-phenyl-4,4,5,5-tetramethylimidazoline-1-oxyl 3-oxide radical (PTIO*) trapping model to study the antioxidant activities of 16 natural xanthones in aqueous solution, including garcinone C, gamma-mangostin, subelliptenone G, mangiferin, 1,6,7-trihydroxy-xanthone, 1,2,5-trihydroxyxanthone, 1,5,6-trihydroxyxanthone, norathyriol, 1,3,5,6-tetrahydroxy-xanthone, isojacareubin, 1,3,5,8-tetrahydroxyxanthone, isomangiferin, 2-hydroxyxanthone, 7-O-methylmangiferin, neomangiferin, and Lancerin. It was observed that most of the 16 xanthones could scavenge the PTIO* radical in a dose-dependent manner at pH 4.5 and 7.4. Among them, 12 xanthones of the para-di-OHs (or ortho-di-OHs) type always exhibited lower half maximal inhibitory concentration (IC50) values than those not of the para-di-OHs (or ortho-di-OHs) type. Ultra-performance liquid chromatography coupled with electrospray ionization quadrupole time-of-flight tandem mass spectrometry (UPLC-ESI-Q-TOF-MS/MS) analysis revealed that most of these xanthones gave xanthone-xanthone dimers after incubation with PTIO*, except for neomangiferin. Based on these data, we concluded that the antioxidant activity of phenolic xanthone may be mediated by electron-transfer (ET) plus H(+)-transfer mechanisms. Through these mechanisms, some xanthones can further dimerize unless they bear huge substituents with steric hindrance. Four substituent types (i.e., para-di-OHs, 5,6-di-OHs, 6,7-di-OHs, and 7,8-di-OHs) dominate the antioxidant activity of phenolic xanthones, while other substituents (including isoprenyl and 3-hydroxy-3-methylbutyl substituents) play a minor role as long as they do not break the above four types.

Chemical investigation of the roots of Polygala sibirica L.[Pubmed:24702811]

Chin J Nat Med. 2014 Mar;12(3):225-8.

AIM: To investigate the chemical constituents of the roots of Polygala sibirica L. (Polygalaceae) METHOD: The isolation was performed by solvent extraction and various chromatographic techniques, including silica gel, Sephadex LH-20, ODS, semi-preparative HPLC, and preparative TLC. The chemical structures were elucidated based on extensive spectroscopic analysis, including HR-ESI-MS and 1D- and 2D-NMR spectroscopic data. RESULTS: A total of sixteen compounds, including five xanthones (5, 7-10), five saccharide esters (1, 3, 4, 12, 13), two flavonoids (14, 16), two triterpenoids (11, 15), one phenylpropanoid (6), and one benzophenone glycoside (2) were isolated. Their structures were determined as sibiricose A7 (1), sibiriphenone A (2), polygalatenoside A (3), polygalatenoside C (4), Lancerin (5), 3, 4, 5-trimethoxycinnamic acid (6), 6-hydroxy-1, 2, 3, 7-tetramethoxyxanthone (7), 1, 3, 7-trihydroxy-2-methoxyxanthone (8), onjixanthone II (9), 1, 2, 3, 6, 7-pentamethoxyxanthone (10), presenegenin (11), 3'-O-3, 4, 5-trimethoxycinnamoyl-6-O-4-methoxy benzoyl sucrose (12), tenuifoliside C (13), 5, 3'-dihydroxy-7, 4'-dimethoxyflavonol-3-O-beta-D-glucopyranoside (14), tenuifolin (15), and rhamnetin 3-O-beta-D-glucopyranoside (16). CONCLUSION: Compounds 1 and 2 are two new compounds from P. sibirica.

Phenolic compounds from the whole plants of Gentiana rhodantha (Gentianaceae).[Pubmed:22006717]

Chem Biodivers. 2011 Oct;8(10):1891-900.

Gentiana rhodantha Franch. ex Hemsl. (Gentianaceae), an annual herb widely distributed in the southwest of China, has been medicinally used for the treatment of inflammation, cholecystitis, and tuberculosis by the local people of its growing areas. Chemical investigation on the whole plants led to the identification of eight new phenolic compounds, rhodanthenones A-D (1-4, resp.), apigenin 7-O-glucopyranosyl-(1-->3)-glucopyranosyl-(1-->3)-glucopyranoside (5), 1,2-dihydroxy-4-methoxybenzene 1-O-alpha-L-rhamnopyranosyl-(1-->6)-beta-D-glucopyranoside (6), 1,2-dihydroxy-4,6-dimethoxybenzene 1-O-alpha-L-rhamnopyranosyl-(1-->6)-beta-D-glucopyranoside (7), and methyl 2-O-beta-D-glucopyranosyl-2,4,6-trihydroxybenzoate (8), together with eleven known compounds, 9-19. Their structures were determined on the basis of detailed spectroscopic analyses and chemical methods. Acetylcholinesterase (AChE) inhibition and cytotoxicity tests against five human cancer cell lines showed that only rhodanthenone D (4) and mangiferin (12) exhibited 18.4 and 13.4% of AChE inhibitory effects at a concentration of 10(-4) M, respectively, while compounds 1-5 and the known xanthones Lancerin (11), mangiferin (12), and neomangiferin (13) displayed no cytotoxicity at a concentration of 40 muM.

Phytochemical re-investigation of Gentiana utriculosa.[Pubmed:19296391]

Nat Prod Res. 2009;23(5):466-9.

Xanthone-O-glycosides with 1,3,7,8-oxidation pattern and flavone isoorientin-3'-O-glucoside were isolated from the aerial parts of Gentiana utriculosa. Xanthone-C-glucoside Lancerin was detected in Gentiana species for the first time. The distribution of these compounds within the section Calathianae is discussed.

Xanthone glycosides from Polygala tenuifolia and their conformational analyses.[Pubmed:15974611]

J Nat Prod. 2005 Jun;68(6):875-9.

Seven xanthone glycosides were isolated from the cortexes of Polygala tenuifolia, and their structures were identified as polygalaxanthones VIII-XI (1-4), sibiricoxanthone B (5), 7-O-methylmangiferin (6), and Lancerin (7), on the basis of spectroscopic analyses. Compounds 1-4 are new xanthone glycosides, and compounds 4 and 5 exist as rotamers. To explain this phenomenon, conformational analyses were performed on compounds 4 and 5 and other compounds with similar skeletons that were isolated from P. tenuifolia.

Effects on anti-lipid peroxidation of Cudrania cochinchinensis var. gerontogea.[Pubmed:7853868]

J Ethnopharmacol. 1994 Oct;44(2):79-85.

From the root bark of Cudrania cochinchinensis (Lour.) Kudo et Masamune var. gerontogea (Sieb. et Zucc.) Kudo et Masamune, 3 xanthones, cudraxanthone I, 1,3,7-trihydroxy-2-(3-methylbut-2- enyl)-xanthone, and Lancerin, were further isolated and characterized. It was found that pretreatment with 600 mg/kg oral dose of the EtOH root extract of Cudrania cochinchinensis var. gerontogea in mice inhibited the lipid peroxidation stimulated by FeCl2-ascorbic acid-adenosine 5'-diphosphate (ADP) mixture. For searching bioactive constituents, the isolated xanthones from this folk medicine were investigated in anti-lipid peroxidative activities in the rat liver homogenate. The results showed that most of the tested xanthones effectively exhibited anti-lipid peroxidation stimulated by (a) FeCl2-ascorbic acid mixture or (b) CCl4-nicotinamide adenine dinucleotide phosphate (NADPH) mixture. As shown by the result, gerontoxanthone C and I were more active than vitamin E.