Guaijaverin

J Appl Microbiol. 2006 Aug;101(2):487-95.

Guaijaverin -- a plant flavonoid as potential antiplaque agent against Streptococcus mutans.[Pubmed: 16882158]

The aim of the present study was to investigate the anti-Streptococcus mutans activity and the in vitro effects of subminimal inhibitory concentrations of Guaijaverin isolated from Psidium guajava Linn. on cariogenic properties of Strep. mutans.
METHODS AND RESULTS:
Bioautography-directed chromatographic fractionation, yield biologically active compound, quercetin-3-O-alpha-l-arabinopyranoside (Guaijaverin), from crude methanol extract of P. guajava. Growth-inhibitory activity of the compound against Strep. mutans of both clinical and type strain cultures was evaluated. The anti-Strep. mutans activity of the Guaijaverin was found to be bacteriostatic, both heat and acid stable and alkali labile with the minimum inhibitory concentration (MIC) of 4 mg ml(-1) for MTCC 1943 and 2 mg ml(-1) for CLSM 001. The sub-MIC concentrations (0.0078-2 mg ml(-1)) of the Guaijaverin were evaluated for its cariogenic properties such as acid production, cell-surface hydrophobicity, sucrose-dependent adherence to glass surface and sucrose-induced aggregation of Strep. mutans.
CONCLUSIONS:
The active flavonoid compound, quercetin-3-O-alpha-l-arabinopyranoside (Guaijaverin) demonstrated high potential antiplaque agent by inhibiting the growth of the Strep. mutans. This study demonstrated the new growth-inhibitory compound Guaijaverin against Strep. mutans and led to the acceptance of traditional medicine and natural products as an alternative form of health care.

Food Science, 2016, 37(7):168-74.

Hypoglycemic Activity of Avicularin and Guaijaverin in Guava Leaves.[Reference: WebLink]

To study the hypoglycemic activity of avicularin and Guaijaverin in guava leaves.
METHODS AND RESULTS:
Reversedphase high performance liquid chromatography(RP-HPLC) was used to determine the content of avicularin and Guaijaverin in guava leaves in different months of the year. The fat cell model was established to evaluate hypoglycemic activity of the ethanol extract of guava leaves, avicularin and Guaijaverin respectively. Western blotting was used to analyze GLUT4 expression on the fat cell membrane. Free fatty acids as another index were also determined using a fatty acid kit. The contents of Guaijaverin and avicularin in guava leaves showed great difference in different months, and guava leaves had higher contents and hypoglycemic activity both between June and September. The guava leaf extract, guajava and avicularin could all significantly promote GLUT4 protein expression on the fat cell membrane and significantly inhibit the release of free fatty acids.
CONCLUSIONS:
Guaijaverin and avicularin are the major bioactive components in guava leaves with hypoglycemic activity and inhibitory capacity against free fatty acid release.

Biosci Biotechnol Biochem. 2010;74(4):878-80.

Inhibitory activity against urease of quercetin glycosides isolated from Allium cepa and Psidium guajava.[Pubmed: 20378972]

Methanolic extracts of edible plants and seaweeds were tested for their inhibitory activity against Jack bean urease.
METHODS AND RESULTS:
Quercetin-4'-O-beta-D-glucopyranoside was isolated from Allium cepa as a urease inhibitor with an IC(50) value of 190 microM-. Quercetin and two quercetin glycosides, avicularin and Guaijaverin, were isolated from Psidium guajava as urease inhibitors with respective IC(50) values of 80 microM-, 140 microM-, and 120 microM-.

Chem. Pharm. Bull. (Tokyo). 2002, 50(6): 788-95.

The methanolic extracts of several natural medicines and medicinal foodstuffs were found to show an inhibitory effect on rat lens aldose reductase. In most cases, flavonoids were isolated as the active constituents by bioassay-guided separation, and among[Pubmed: 12045333]

The methanolic extracts of several natural medicines and medicinal foodstuffs were found to show an inhibitory effect on rat lens aldose reductase.
METHODS AND RESULTS:
In most cases, flavonoids were isolated as the active constituents by bioassay-guided separation, and among them, quercitrin (IC(50)=0.15 microM), Guaijaverin (0.18 microM), and desmanthin-1 (0.082 microM) exhibited potent inhibitory activity. Desmanthin-1 showed the most potent activity, which was equivalent to that of a commercial synthetic aldose reductase inhibitor, epalrestat (0.072 microM). In order to clarify the structural requirements of flavonoids for aldose reductase inhibitory activity, various flavonoids and related compounds were examined.
CONCLUSIONS:
The results suggested the following structural requirements of flavonoid: 1) the flavones and flavonols having the 7-hydroxyl and/or catechol moiety at the B ring (the 3',4'-dihydroxyl moiety) exhibit the strong activity; 2) the 5-hydroxyl moiety does not affect the activity; 3) the 3-hydroxyl and 7-O-glucosyl moieties reduce the activity; 4) the 2-3 double bond enhances the activity; 5) the flavones and flavonols having the catechol moiety at the B ring exhibit stronger activity than those having the pyrogallol moiety (the 3',4',5'-trihydroxyl moiety).

Spectrochim Acta A Mol Biomol Spectrosc. 2012 Nov;97:449-55.

Exploring the binding mechanism of Guaijaverin to human serum albumin: fluorescence spectroscopy and computational approach.[Pubmed: 22820048]

The Guaijaverin (Gua) is a polyphenolic substance which exhibits some pharmacological activities such as antibacterial and antioxidant activities.
METHODS AND RESULTS:
Here we have investigated the binding of Gua with human serum albumin (HSA) at physiological pH 7.0. In this study, the fluorescence spectroscopy, ab initio and molecular modeling calculations were applied. The Stern-Volmer quenching constant (K(SV)) and its modified form (K(a)) were calculated at 298, 303 and 308 K, with the corresponding thermodynamic parameters ΔH, ΔG and ΔS as well. The fluorescence quenching method was used to determine the number of binding sites (n) and binding constants (K(b)) values at 298, 303 and 308 K. The distance between donor (HSA) and acceptor (Gua) was estimated according to fluorescence resonance energy transfer. The geometry optimization of Gua was performed in its ground state by using ab initio DFT/B3LYP functional with a 6-31G(d,p) basis set used in calculations.
CONCLUSIONS:
Molecular modeling calculation indicated that the Gua is located within the hydrophobic pocket of the subdomain IIA of HSA. The theoretical results obtained by molecular modeling were corroborated by fluorescence spectroscopy data.