Antioxidant activities of Lampaya medicinalis extracts and their main chemical constituents.

Glauco Morales,Adrián Paredes

doi:10.1186/1472-6882-14-259

Glauco Morales, Adrián Paredes

Open Access

https://doi.org/10.1186/1472-6882-14-259

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Abstract

BackgroundLampaya medicinalis Phil. (Verbenaceae) is a plant used by Aymara and Quechua ethnic groups from Northern Chile as folk medicine in the treatment and cure of various diseases. The aim of this study was to investigate the in vitro antioxidant activity, total phenols content, total flavonoids content, total antioxidant activity, reducing power, brine shrimp cytotoxicity and identify the principal chemical constituents.MethodsThe crude hydroethanolic extract (HEE) and its partitioned fraction: hexane (HF), dichloromethane (DF), ethyl acetate (EAF), n-butanol (BF) and soluble residual aqueous fraction (RWF) were evaluated for their antioxidant activity using different assays namely, DPPH, ABTS, FRAP, β-carotene bleaching assay. The content of total phenolics and total flavonoids were measured by Folin-Ciocalteau and by the AlCl3 colorimetric method, respectively. Reducing power was determined by phosphomolybdate and hexacyanoferrate (III) methods. Biotoxicity assays were performed on shrimps of Artemia salina. The EAF was fractionated using chromatographic methods.ResultsConsiderable amount of phenolic and flavonoid contents were recorded in the hydroethanolic extract (HEE) and its derived fractions. Although HEE and all its derived fractions exhibited good antioxidant activities, the most distinguished radical scavenging potential was observed for ethyl acetate fraction (EAF). EAF showed the higher radical scavenging activity by DPPH (95%) and by ABTS (98%), antioxidant activity by FRAP (158.18 ± 5.79 mg equivalent Trolox/g fraction), β-carotene bleaching assay (86.8%), the highest total phenols content (101.26 ± 1.07 mg GAE/g fraction), the highest total flavonoids content (66.26 ± 3.31 μg quercetin/g fraction). The EAF extract showed an reducing power of 78% and 65% using the phosphomolybdate and hexacyanoferrate (III) assays, respectively.Four flavonoids, two p-hydroxyacetophenone derivatives and one iridoid were isolated from Lampaya medicinalis for the first time.ConclusionEtOAc soluble fraction (EAF) shows the strongest antioxidant activity, and it can be attributed to its high content in phenolic and flavonoid compounds. It can be concluded that L.medicinalis can be used as an effective natural source of antioxidant, as ethnomedicine and as a commercial basis for the development of nutraceuticals.

Highlights

Lampaya medicinalis Phil. (Verbenaceae) is a plant used by Aymara and Quechua ethnic groups from Northern Chile as folk medicine in the treatment and cure of various diseases
This paper reports the evaluation of the antioxidant activities of hydroethanolic extract (HEE) and its partitioned fraction of Lampaya medicinalis, using different assays namely, 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2’-Azino bis(3-ethylbenzothiazoline-6-sulfonic acid (ABTS), β-carotene bleaching assay, Ferric reducing/Antioxidant Power assays (FRAP)
Maximum quantity of total phenol content was observed in EtOAc soluble fraction (EAF), 101.26 ± 1.07 mg Gallic Acid Equivalents (GAE)/g fraction, with a significant difference with the rest of the fractions, followed by HEE and RWF with 49.18 ± 0.86 mg GAE/g fraction and 48.41 ± 0.91 mg GAE/g fraction, respectively

Summary

Introduction

Lampaya medicinalis Phil. (Verbenaceae) is a plant used by Aymara and Quechua ethnic groups from Northern Chile as folk medicine in the treatment and cure of various diseases. Free radicals are chemical species which contain one or more unpaired electrons in their outer shell. They are highly unstable and cause damage to other molecules by extracting electrons from them in order to attain stability. The oxidation induced by ROS can result in cell membrane disintegration, membrane protein damage and DNA mutation, which can further initiate or propagate the development of many diseases, such as cancer, diabetes, liver injury, arteriosclerosis and cardiovascular disease [3]. The human body possesses physiological defense mechanisms that reduce the damaging properties of ROS, continuous exposure to various factors and pathological conditions can lead to an increase in the amount of free radicals and cause irreversible oxidative damage. In humans the over-production of ROS can result in tissue injury and has been implicated in disease progression. Free radicals have been associated with several diseases such as inflammation, cardiovascular accidents, cancer, agingrelated disorders and atherosclerosis [4]

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