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This document summarizes a study on the antioxidant and DNA protective properties of extracts from four Mauritian fruits - olive, bilimbi, amla, and mangosteen. Chemical profiling of the extracts found a variety of phytochemicals including phenols, flavonoids, tannins, and terpenes. Mangosteen extracts had the highest total phenol and flavonoid contents. Mangosteen and bilimbi extracts also showed the strongest antioxidant activities in DPPH radical scavenging assays. Certain extracts, especially dichloromethane and hexane fractions of mangosteen, demonstrated good protection of plasmid DNA against free radical damage. Overall, the study found the selected fruits to have promising antioxidant
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- 1. By Marie Muriel Stephanie Jugoo BSc (Hons) Biotechnology Faculty of Agriculture University of Mauritius June 2015 1
- 2. Introduction Methodology Results Discussion Conclusion Recommendations References 2
- 3. 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. 3
- 4. Elaeocarpus floribundus Averrhoa bilimbi Emblica officinalis Garcinia dulcis Anti-oxidant activity 4
- 5. 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 5
- 6. Sample collection & Preparation Extraction by maceration Decantation & Filtration Extract concentration 6
- 7. Qualitative screening Quantitative screening: Total Phenol & Flavonoids In vitro antioxidant activity: DPPH free radical scavenging DNA nicking assay 7
- 8. 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. 8
- 9. Olive Bilimbi Amla Mangosteen Methanol 2.458 3.688 26.567 11.319 Dichloromethane 1.423 1.617 1.649 31.533 Hexane 5.75 3.925 9.897 75.356 0 10 20 30 40 50 60 70 80 Figure 1. Comparative analysis of the total phenolic content (μg GAE/g extract) of the extracts 9
- 10. Olive Bilimbi Amla Mangosteen Methanol 254.63 291.767 452.193 925.858 Dichloromethane 444.444 317.073 603.946 273.148 Hexane 794.11 839.646 638.889 511.574 0 100 200 300 400 500 600 700 800 900 1000 Figure 2. Comparative analysis of total flavonoid content (μg QE/g extract) of the extracts 10
- 11. Sample IC50 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). 11 Table 1. IC50 values of the fruit extracts
- 12. 1 2 3 4 5 6 7 8 9 10 11 12 13 15 16 1714 Nicked Linear Supercoiled 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. 12
- 13. 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 13
- 14. 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. 14
- 15. 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. 15
- 16. 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). 16
- 17. 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 17
- 18. 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. 18
- 19. 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. 19
- 20. 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. 20
- 21. Thank you for your attention 21