Study of the Electrophoretic Behaviour of Flavonoids

Beneficial roles of honey polyphenols against some human degenerative diseases: A review

Honey contains many active constituents and antioxidants such as polyphenols. Polyphenols are phytochemicals, a generic term for the several thousand plant-based molecules with antioxidant properties. Many in vitro studies in human cell cultures as well as many animal studies confirm the protective effect of polyphenols on a number of diseases such as cardiovascular diseases (CVD), diabetes, cancer, neurodegenerative diseases, pulmonary diseases, liver diseases and so on. Nevertheless, it is challenging to identify the specific biological mechanism underlying individual polyphenols and to determine how polyphenols impact human health. To date, several studies have attempted to elucidate the molecular pathway for specific polyphenols acting against particular diseases. In this review, we report on the various polyphenols present in different types of honey according to their classification, source, and specific functions and discuss several of the honey polyphenols with the most therapeutic potential to exert an effect on the various pathologies of some major diseases including CVD, diabetes, cancer, and neurodegenerative diseases.

Contribution of constitutive characteristics of lipids and phenolics in roots of tree species in Myrtales to aluminum tolerance

High aluminum (Al) concentration in soil solution is the most important factor restricting plant growth in acidic soils. However, various plant species naturally grow in such soils. Generally, they are highly tolerant to Al, but organic acid exudation, the most common Al tolerance mechanism, cannot explain their tolerance. Lower phospholipid and higher sterol proportions in root plasma membrane enhance Al tolerance. Other cellular components, such as cell walls and phenolics, may also be involved in Al tolerance mechanisms. In this study, the relationships between these cellular components and the Al tolerance mechanisms in Melastoma malabathricum and Melaleuca cajuputi, both highly Al-tolerant species growing in strongly acidic soils, were investigated. Both species contained lower proportions of phospholipids and higher proportions of sterols in roots, respectively. Concentrations of phenolics in roots of both species were higher than that of rice; their phenolics could form chelates with Al. In these species, phenolic concentrations and composition were the same irrespective of the presence or absence of Al in the medium, suggesting that a higher concentration of phenolics is not a physiological response to Al but a constitutive characteristic. These characteristics of cellular components in roots may be cooperatively involved in their high Al tolerance.

Determination of polyphenolics in extracts of Potentilla species by high-performance thin-layer chromatography photodensitometry method

INTRODUCTION

Separation of polyphenolics in different plant materials using high-performance thin-layer chromatography (HPTLC) represents an effective method for their detection and quantification.

OBJECTIVE

To develop a simple, specific, precise, sensitive and accurate method for the simultaneous quantification of tiliroside (TRS), methyl brevifolincarboxylate (MBR) and ellagic acid (EA) in a plant extract using the HPTLC-photodensitometry method.

METHODOLOGY

Aerial parts of the selected Potentilla species, P. anserina, P. erecta, P. grandiflora and P. nepalensis var. 'Miss Willmott', were extracted with methanol. After solvent evaporation, the methanolic extracts were diluted with water and successively partitioned between chloroform and then diethyl ether. The diethyl ether extracts from each sample were used for quantification. The analyses were performed on HPTLC precoated silica gel 60F(254) plates with toluene-ethyl formate-formic acid (6 : 4 : 1 v/v/v) as the mobile phase (distance of 7.5 cm). Densitometric detections of TRS, MBR and EA were performed at 320, 287 and 280 nm, respectively. The amounts of these compounds were calculated using the regression equations of the calibration curves, which were linear within a range of 0.05-0.5 microg/spot (R(2) = 0.9957) for TRS, 0.05-0.525 microg/spot (R(2) = 0.9965) for MBR and 0.0525-0.5 microg/spot (R(2) = 0.9998) for EA.

RESULTS

The amounts of marker compounds measured by the method developed are expressed in mg/g of dry extracts. TRS ranged from 20.3 +/- 0.3 mg/g for P. erecta herbs to 197.7 +/- 2.9 mg/g for P. grandiflora herbs; MBR ranged from 5.0 +/- 0.6 mg/g for P. erecta herbs to 68.5 +/- 3.4 mg/g for P. nepalensis flowers; and EA ranged from 24.0 +/- 0.6 mg/g for P. erecta herbs to 216.2 +/- 3.2 mg/g for P. anserina leaves.

CONCLUSION

The proposed method was found to be relatively simple, specific, precise, sensitive and accurate and may be used for the routine assay of simultaneous determination of TRS, MBR and EA in other extracts and phytomedicines containing Potentilla species.