Helichrysoside

Glucose Tolerance-Improving Activity of Helichrysoside in Mice and Its Structural Requirements for Promoting Glucose and Lipid Metabolism.[Pubmed:31847420]

Int J Mol Sci. 2019 Dec 14;20(24). pii: ijms20246322.

An acylated flavonol glycoside, Helichrysoside, at a dose of 10 mg/kg/day per os for 14 days, improved the glucose tolerance in mice without affecting the food intake, visceral fat weight, liver weight, and other plasma parameters. In this study, using hepatoblastoma-derived HepG2 cells, Helichrysoside, trans-tiliroside, and kaempferol 3-O-beta-D-glucopyranoside enhanced glucose consumption from the medium, but their aglycones and p-coumaric acid did not show this activity. In addition, several acylated flavonol glycosides were synthesized to clarify the structural requirements for lipid metabolism using HepG2 cells. The results showed that Helichrysoside and related analogs significantly inhibited triglyceride (TG) accumulation in these cells. The inhibition by Helichrysoside was more potent than that by other acylated flavonol glycosides, related flavonol glycosides, and organic acids. As for the TG metabolism-promoting activity in high glucose-pretreated HepG2 cells, Helichrysoside, related analogs, and their aglycones were found to significantly reduce the TG contents in HepG2 cells. However, the desacyl flavonol glycosides and organic acids derived from the acyl groups did not exhibit an inhibitory impact on the TG contents in HepG2 cells. These results suggest that the existence of the acyl moiety at the 6'' position in the D-glucopyranosyl part is essential for glucose and lipid metabolism-promoting activities.

Anti-oxidative and cholinesterase inhibitory effects of leaf extracts and their isolated compounds from two closely related Croton species.[Pubmed:23377133]

Molecules. 2013 Feb 1;18(2):1916-32.

A comparative evaluation of the antioxidant and acetylcholinesterase inhibitory activity of the leaf extracts of Croton gratissimus and Croton zambesicus (subgratissimus) and compounds isolated from the extracts was carried out to determine their potential and suitability or otherwise as a substitute for each other in the management of oxidative and neurodegenerative conditions. Different antioxidant assays (DPPH, FRAP, beta-carotene-linoleic and the lipid peroxidation models) and the microplate assay for acetylcholinesterase (AChE) inhibition were carried out separately to study the activities of the crude leaf extracts and four solvent fractions from each of the two Croton species. Bioassay guided fractionation was used to target antioxidant constituents of the crude extracts and ethyl acetate fractions of 20% aqueous methanol extract of C. gratissimus on silica gel and Sephadex LH-20 columns resulted in the isolation of kaempferol-3-O-beta-6''(p-coumaroyl) glucopyranoside (tiliroside, 2), apigenin-6-C-glucoside (isovitexin, 3) and kampferol (4). The extract of C. zambesicus yielded quercetin-3-O-beta-6''(p-coumaroyl) glucopyranoside-3'-methyl ether (Helichrysoside- 3'-methyl ether, 1), kaempferol-3-O-beta-6''(p-coumaroyl) glucopyranoside (tiliroside, 2) and apigenin-6-C-glucoside (isovitexin, 3). Three of the isolated compounds and their different combinations were also included in the bioassays. In all the assays performed, the antioxidant capacity and AChE inhibitory effects of C. zambesicus extracts were weaker than those of C. gratissimus. This suggests that C. gratissimus may not be substituted by C. zambesicus, despite the similarity in some of their constituents. Generally, the combinations made from the isolated compounds showed better activities in most of the assays compared to the individual isolated compounds. This suggests mechanisms such as synergism and/or additive effects to be taking place. This study established low, moderate and high antioxidant activities as well as AChE inhibitory effects by the crude extracts, fractions, compounds and compound combinations. This means some of the extracts, isolated compounds and compound combinations could be useful in the management of neurodegenerative conditions and serve as sources of natural neurodegenerative agents.

Isolation and characterisation of novel antioxidant constituents of Croton zambesicus leaf extract.[Pubmed:21762034]

Nat Prod Res. 2011 Aug;25(13):1224-33.

A 1,1-diphenyl-2-picrylhydrazyl (DPPH)-activity-directed fractionation was used to target antioxidant constituents of the ethyl acetate fraction obtained from a 20% aqueous methanol crude extract of Croton zambesicus leaf. Repeated column chromatography of the fraction on silica gel and Sephadex LH-20 led to the isolation of a new natural product, identified as quercetin-3-O-beta-6''(p-coumaroyl) glucopyranoside-3'-methyl ether, Helichrysoside-3'-methyl ether (1), along with kaempferol-3-O-beta-6''(p-coumaroyl) glucopyranoside, tiliroside (2) and apigenin-6-C-glucoside, isovitexin (3) as the antioxidant constituents. The structures of the isolated compounds were elucidated using spectroscopic techniques, namely NMR (1D and 2D) and mass spectrometry. Compounds 1 and 2 are reported from this species for the first time. In the qualitative antioxidant assay, the three isolated compounds instantly bleached the DPPH (0.2% MeOH) purple colour indicating antioxidant activity. In the quantitative antioxidant assay, all the isolated compounds demonstrated weak antioxidant activity compared to quercetin and rutin used as positive control antioxidant agents. The compounds displayed little to no cytotoxicity against Vero cells in an in vitro assay. The presence of these antioxidant compounds in the leaf extract of C. zambesicus could provide a rationale for the ethnomedicinal use of the plant in the management of oxidative-stress-related diseases in folk medicine.

[Chemical constituents of Laggera pterodonta].[Pubmed:20506820]

Zhongguo Zhong Yao Za Zhi. 2010 Mar;35(5):602-6.

OBJECTIVE: To study the chemical constituents of Laggera pterodonta. METHOD: The ethanol extract of L. pterodonta was isolated by column chromatogramphy on silica gel, ODS, and Sephadex LH-20 to afford compounds. The structures of the obtained compounds were identified by chemical reactions and spectroscopic analysis. RESULT: Nineteen compounds were separated and identified to be pterodondiol (1), ilicic acid (2), artemitin (3), chrysosplenetin B (4), 3,5-dihydroxy-3',4',6,7-tetramethoxyflavone (5), chrysosplenol D (6), 5,6,4'-trihydroxy-3,7-dimethoxyflavone (7), quercetin (8), tamarixetin (9), patuletin (10), quercetin-3-O-beta-D-galactopyranoside (11), patuletin-3-O-beta-D-glucopyranoside (12), Helichrysoside (13), 4,5,7-trihydroxy-6-methoxyflavone-3-O-beta-D-rutinoside (14), kaempferol-3-O-beta-D-glucopyranoside (15), stigmasterol (16), stigmasterol 3-O-beta-D-glucopyranoside (17), 2-hydroxy-benzoic acid (18), beta-sitosterol (19). CONCLUSION: Compounds 5, 7, 9-15, and 17-18 were isolated from this plant for the first time. The 13C-NMR data of compound 7 is reported for the first time.

Antihypertensive principles from the leaves of Melastoma candidum.[Pubmed:8255931]

Planta Med. 1993 Oct;59(5):405-7.

Three active principles were isolated from the leaf of Melastoma candidum using the screening of hypotensive effects on spontaneously hypertensive rats (SHR). Intravenous injection of castalagin, procyanidin B-2, or Helichrysoside into SHR lowered the mean blood pressure in a dose-dependent manner, with Helichrysoside being the most potent compound. Plasma noradrenaline (NA) levels, both basal in SHR and elevated in normal rats through cold-stress stimulation, were attenuated by these compounds in a way which was not influenced by adrenalectomy. Decrease of NA release from sympathetic nerves was assumed to be responsible. Moreover, the hypertensive effect of various vasoconstrictors in anesthetized rats was reduced by Helichrysoside. The same results were also observed in castalagin or procyanidin B-2 treated animals. The results indicate that the three principles possess the ability to lower blood pressure through a decrease of sympathetic tone as well as due to direct vasodilatation in SHRs.