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Assessing and evaluating phytochemicals with antioxidant

properties and DNA protective potential of selected fruit species from Mauritius

By Marie Muriel Stephanie Jugoo

BSc (Hons) BiotechnologyFaculty of Agriculture

University of MauritiusJune 2015

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Overview

Introduction Methodology Results Discussion Conclusion Recommendations References

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Introduction

Our tropical island holds a myriad of natural remedies against a range of diseases.

Based on a local survey, Chintamunnee and Mahomoodally (2012) concluded that Mauritians are now shifting back towards natural plant- derived products that are much effective and benign.

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Introduction

Elaeocarpus floribundus

Averrhoa bilimbi Emblica officinalis Garcinia dulcis

Anti-oxidant activity

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Objectives

To screen different extracts of selected fruits for the presence of phytochemicals

To quantify the chemicals detected in the fruit extracts

To evaluate the free radical scavenging potential of the extracts

To assess the DNA protective potential of the selected fruit extracts

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Methodology: Extract preparation

Sample collection & Preparation

Extraction by maceration

Decantation & Filtration

Extract concentration

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Methodology: Extract evaluation

Qualitative screening

Quantitative screening: Total Phenol & Flavonoids

In vitro antioxidant activity: DPPH free radical scavenging

DNA nicking assay

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Results: Qualitative Phytochemical Screening The majority of tannins present were hydrolysable

tannins, except in Garcinia dulcis extracts that contained condensed tannins.

Overall, tests for tannins, leucoanthraquinones, steroids, flavonols and phenols were positive in all the fruit extracts.

Presence of saponins and anthraquinones depended on the fruit species and solvent used.

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Results: Quantitative Phytochemical Screening

Olive Bilimbi Amla Mangosteen0

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70

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Figure 1. Comparative analysis of the total phenolic content (μg GAE/g extract) of the extracts

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Results: Quantitative Phytochemical Screening

Olive Bilimbi Amla Mangosteen0

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200

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700

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900

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Figure 2. Comparative analysis of total flavonoid content (μg QE/g extract) of the extracts

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DPPH free radical scavenging assay

SampleIC50 Values (mg/mL)

Methanol DCM Hexane

Olive 37.666 8.571 32.321

Bilimbi 8.334 11.286 16.429

Amla 0.672 49.544 4.773

Mangosteen 0.821 0.595 8.043

None of the extracts showed lowest IC50 compared to the standard Quercetin (0.0123 mg/mL).

Table 1. IC50 values of the fruit extracts

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DNA nicking assay1 2 3 4 5 6 7 8 9 10 11 12 13 15 16 1714

NickedLinearSupercoiled

Figure 3. 1% agarose gel loaded with sample tests with maximum protection

Higher protection of the plasmid was denoted to be with olive hexane, Mangosteen DCM, Mangosteen hexane and Bilimbi DCM.

Diluted into 25, 50 and 100 μg/μL. Quercetin served as positive control and methanol as negative control.

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Discussion: Phytochemical profile Chemical profiling of the different fruit extracts revealed a

wide spectrum of secondary metabolites present,

Namely coumarins, saponins, anthraquinones, leucoanthraquinones, flavonols, steroids, alkaloids, phenols and higher occurrence of hydrolysable tannins among the four selected varieties.

Variations observed in the phyto-profiles mainly due to:(1) Extraction technique (time & temperature)(2) Efficiency of solvent (polarity & concentration)(3) Maturity of fruits(4) Environmental conditions & abiotic stresses

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Discussion: Total Phenolic and Flavonoid contents Highest phenolic contents were noted in hexane fraction of

Elaeocarpus floribundus (Olive), Averrhoa bilimbi and Garcinia dulcis (Mangosteen) fruits. Previous studies revealed that the maximum TPC was recorded

with hexane fraction

The highest flavonoid content was seen to be in methanol fraction of Garcinia dulcis (Mangosteen). Methanol is a good extraction solvent and also, the fruit has high

water content. The water allowed more phytochemicals to be extracted.

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Discussion: Antioxidant activity Previous work related antioxidant activities to the flavonoids

content of the sample (Chae et al., 2013).

Highest antioxidant potential was noted in Mangosteen (Garcinia dulcis) with 94.24 % inhibition. high level of flavonoids (925.858 μg QE/g extract)

The general trend was that when the total flavonoids content was high, the antioxidant potential of the extract was boosted.

However, high phenol contents also positively influenced the antioxidant activity.

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Discussion: Antioxidant activity Hexane fraction of Mangosteen (Garcinia dulcis) –

low flavonoid content but, high level of phenolics.

Hexane mainly elutes terpenes, fatty acids and steroids.

Among these non-polar phytochemicals, it was reported that terpenes show antioxidant activities (Grassmann, 2005).

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Discussion: DNA nicking assay Ability of the extract to protect pUC18 from free

radical damage (Fe3+).

DCM and hexane fractions of Mangosteen showed good protection since they had high antioxidant activities at 100 mg/mL (94.24% and 90.81% respectively).

Disparities in the other fruit extracts could be due to the fact that phytochemicals act in synergy

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Conclusion The selected fruits hold interesting antioxidant and

DNA protective potentials.

Mangosteen (Garcinia dulcis) showed promising future due to its high level of phenolics and flavonoids, which impact on its antioxidant properties.

Positive correlation between total flavonoid content and antioxidant activity of the extracts. Though, some variations were seen, they only corroborate findings about synergic actions of phytochemicals.

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Recommendations

Combined solvent systems can be used for increase extraction yields.

Collection of the samples at different maturity stage and different locations so as to get a broader view of the phytochemical profile of local fruits.

Other scavenging assays such as ABTS+, ORAC (Oxygen-radical absorbance capacity) and FRAP (Ferric reducing ability of plasma assays) can be used to assess the potential of the fruit extracts.

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References Chintamunnee, V. and Mahomoodally, M.F., 2012. Herbal medicine commonly

used against non-communicable diseases in the tropical island of Mauritius. Journal of Herbal Medicine, 2(4), pp 113-125.

Chae, S.C., Lee, J.H. and Park, S.U., 2013. Recent studies on flavonoids and their antioxidant activities. EXCLI Journal, 12, pp 225-230.

Dhale, D.A. and Mogle, U.P., 2011. Phytochemical Screening and Antibacterial Activity of Phyllanthus emblica (L.). Science Research Reporter, 1(3), pp 138- 142.

Doughari, J.H., 2012. Phytochemicals: Extraction Methods, Basic Structures and Mode of Action as Potential Chemotherapeutic Agents. In: V. Rao, ed. Phytochemicals - A Global Perspective of Their Role in Nutrition and Health. InTech, pp 1-32.

Grassmann, J., 2005. Terpenoids as plant antioxidants. Vitamins and hormones, 72, pp 505-535.

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Thank you for your attention