Antioxidant actions and phenolic and vitamin C contents of common Mauritian exotic fruits

Antioxidant actions and phenolic and vitamin C contents of common Mauritian exotic fruits Journal of the Science of Food and Agriculture J Sci Food Agric 83 496–502 (online 2003) DOI 10 1002/jsfa 1365[.]

Journal of the Science of Food and Agriculture J Sci Food Agric 83:496–502 (online: 2003) DOI: 10.1002/jsfa.1365 Antioxidant actions and phenolic and vitamin C contents of common Mauritian exotic fruits Amitabye Luximon-Ramma,1 Theeshan Bahorun1∗ and Alan Crozier2 Department ´ of Biological Sciences, Faculty of Sciences, University of Mauritius, Reduit, Mauritius Products and Human Nutrition Group, Graham Kerr Building, Division of Biochemistry and Molecular Biology, Institute of Biomedical and Life Sciences, University of Glasgow, Glasgow G12 8QQ, UK Plant Abstract: Seventeen commonly consumed exotic fruits from Mauritius were analysed for their antioxidant capacity, total phenolics, proanthocyanidins, flavonoids and vitamin C content Two independent methods were used to evaluate the antioxidant potential of total fruit extracts The antioxidant activities of the fruits ranged from to 47 µmol Trolox equivalent antioxidant capacity (TEAC) g−1 fresh weight and from 11 to 360 µmol ferric reducing antioxidant power (FRAP) g−1 fresh weight Total phenolics in the fruits ranged from 118 to 5638 µg g−1 fresh weight, proanthocyanidins from to 2561 µg g−1 fresh weight, flavonoids from 21 to 712 µg g−1 fresh weight and vitamin C content from to 1426 µg g−1 fresh weight There were strong correlations between antioxidant activity (assessed by both TEAC and FRAP) and total phenolics and proanthocyanidins Flavonoids seemed to contribute less to the antioxidant potential of the fruits, while very poor correlations were observed between ascorbate content and antioxidant activity The highest antioxidant capacities were observed in red and yellow Psidium cattleianum Sabine ‘Chinese guava’, sweet and acid Averrhoa carambola L ‘starfruit’, Syzygium cumini L Skeels ‘jamblon’ and white Psidium guajava L ‘guava’ These fruits were also characterised by high levels of total phenolics Mauritian exotic fruits are thus a significant source of phenolic antioxidants, which may have potential beneficial effects on health  2003 Society of Chemical Industry Keywords: exotic fruits; antioxidant activity; TEAC; FRAP; total phenols; proanthocyanidins; flavonoids; vitamin C INTRODUCTION There is convincing evidence of the beneficial role of fruits and vegetables in the diet for the maintenance of health and prevention of disease.1 – Cellular damage caused by exposure to high levels of free radicals induces cardiovascular disorders, neurological dysfunctions and various cancers.4 – It is believed that fruits and vegetables provide protection against these disorders because they are rich sources of antioxidants, which scavenge free radicals and thereby reduce the incidence of degenerative pathologies.7 – The compounds thought to be responsible for the protective effects of a fruit-and-vegetable-rich diet include carotenoids and antioxidant vitamins such as ascorbic acid and tocopherols However, there is growing evidence that other phytochemicals contribute to varying degrees to the antioxidant capacity of individual fruits or vegetables In this regard, interest has focused on the significance of phenolics such as catechins, phenolic acids, flavonoids, proanthocyanidins and anthocyanins.10,11 These compounds have exhibited a range of biological effects including antibacterial, antiviral, anti-inflammatory, antithrombotic and vasodilatory actions.12 – 14 They also exert pronounced antioxidant and free radical-scavenging activities.15 – 19 It is important to note that many biological functions such as antimutagenicity, anticarcinogenicity and antiaging stem from this property.20 – 22 Interest in the role of antioxidants in human health, particularly with regard to the relatively high incidence of cardiovascular diseases, cancers and diabetes in Mauritius,23 has prompted research in the field of horticulture and food science to study the phytochemistry and antioxidant capacity of Mauritian fruits and vegetables The current investigation examined the relationship between the in vitro antioxidant capacity and the total phenolic, proanthocyanidin, flavonoid and vitamin C contents in some selected exotic Mauritian fruits MATERIALS AND METHODS Standards and chemicals ABTS (2,2 -azino-bis(3-ethylbenzthiozoline-6-sulphonic acid) and TPTZ (2,4,6-tri(2-pyridyl)-s-triazine) were from Sigma Co (St Louis, MO, USA) Trolox ∗ ´ Correspondence to: Theeshan Bahorun, Department of Biological Sciences, Faculty of Sciences, University of Mauritius, Reduit, Mauritius E-mail: tbahorun@uom.ac.mu Contract/grant sponsor: Mauritius Research Council (Received June 2002; revised version received 30 August 2002; accepted 12 December 2002)  2003 Society of Chemical Industry J Sci Food Agric 0022–5142/2003/$30.00 496 Antioxidant actions of Mauritian exotic fruits (6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid), a water-soluble analogue of vitamin E, was purchased from Sigma-Aldrich (DeisenhaBen Germany) HPLC grade quercetin and cyanidin chloride were obtained from Extrasynth`ese (Genay, France) All other reagents used were of analytical grade Fruit samples All fruit samples were collected during the year 2000 fruit-bearing season Samples of red and yellow Psidium cattleianum fruits were obtained from Bigarra and Petrin (central Mauritius) respectively, while Syzygium cumini fruits were from Black River (west Mauritius) All other mature ripe fruits were harvested at random from ‘La Compagnie Agricole de Labourdonnais’ at Mapou in northern Mauritius The determination of fruit maturity and ripeness was based on fruit firmness and surface colour Table lists the names of the studied species, their fruit types/subcultivars, harvest sites and parts used for analysis Voucher specimens of fruit samples have been deposited in the Department of Biological Sciences, Faculty of Science, University of Mauritius Extraction Polyphenols Portions (100 g) of the edible parts of fresh fruits were homogenised in acetone/water (70:30 v/v; × 300 ml) using a Waring blender and left to macerate for 24 h at ◦ C After filtration the residue was homogenised in absolute methanol (2 × 300 ml) and again left to macerate for 24 h at ◦ C Acetone was removed from the combined filtrates in vacuo at 37 ◦ C and the aqueous residue was washed with dichloromethane (3 × 150 ml) to remove fat-soluble substances The aqueous extract was concentrated in vacuo at 37 ◦ C and divided into two equal aliquots One was freezedried and redissolved in methanol at a final 1:5 fresh weight/volume ratio and was used for the quantitative analysis of phenolic compounds The second aliquot was used to determine the antioxidant activity Vitamin C A modified method of Daood et al 24 was used for the extraction of vitamin C from fresh fruits Portions (10 g) of fruit material were homogenised with 40 ml of a solution of 30 g l−1 metaphosphoric acid in 80 g l−1 glacial acetic acid (pH 1.5) for using a Waring blender The extracts were then mechanically shaken for 15 in darkness After filtration the clear extracts were stored at −40 ◦ C for subsequent analysis Total phenolic content analysis Total phenolics were determined by the method of Singleton and Rossi25 using the Folin–Ciocalteu reagent Results were expressed as µg gallic acid equivalent g−1 fresh weight Total proanthocyanidin content analysis The HCl/butan-1-ol assay of Porter et al 26 was used to quantify total proanthocyanidins Result were expressed as µg cyanidin chloride equivalent g−1 fresh weight Total flavonoid content analysis The AlCl3 method adapted from Ref 27 was used to determine the total flavonoid content of the methanolic extracts Results were expressed as µg quercetin equivalent g−1 fresh weight Vitamin C content analysis The vitamin C content of the fruit extracts was determined by the 2,6-dichloroindophenol titrimetric method (AOAC).28 Results were expressed as µg ascorbic acid equivalent g−1 fresh weight Measurement of antioxidant activity Trolox equivalent antioxidant capacity (TEAC) The antioxidant activity of total fruit extracts was measured in terms of radical-scavenging ability Table Details of 17 Mauritian exotic fruits studied Common name Scientific name Starfruit Averrhoa carambola L Chinese guava Psidium cattleianum Sabine Guava Psidium guajava L Hogplum Pineapple Banana Avocado Jamalac Jamblon Passion fruit Mango Papaya Litchi Longanberry Spondias dulcis Sonn Ananas comosus (L) Merrill Musa acuminata (diploides) Persea americana P Miller Syzygium samarangense (Blume) Merr et Perry Syzygium cumini (L) Skeels Passiflora edulis Sims Mangifera indica L Carica papaya L Litchi chinensis Sonnerat Euphoria longan (Lour) Steud J Sci Food Agric 83:496–502 (online: 2003) Fruit type/subcultivar Harvest site Part used Acid Sweet Red Yellow Pink White — Bourgault Gingeli — — — Orange Maison Rouge Exotica — — Mapou Mapou Bigarra Petrin Mapou Mapou Mapou Mapou Mapou Mapou Mapou Black River Mapou Mapou Mapou Mapou Mapou Whole Whole Whole Whole Whole Whole Skin + pulp Pulp Pulp Pulp Pulp Pulp Pulp + seed Pulp Pulp Pulp Pulp 497 according to the ABTS/MnO2 method of Campos and Lissi.29 Results were expressed as µmol Trolox equivalent g−1 fresh weight Ferric reducing antioxidant power (FRAP) assay The methodology of Benzie and Strain30 was used Results were expressed as µmol Fe(II) g−1 fresh weight Statistical analysis Simple regression analysis was performed to calculate the dose–response relationship of the standard solutions used for calibration as well as the test samples Linear regression analysis was performed, quoting the correlation coefficient rxy between antioxidant activity, phenolic class and vitamin C Unicam UV Series Vision 32 software (Version 1.22, Unicam Instruments, Cambridge, UK) was used to evaluate initial and final antioxidant values for the TEAC assay Results were expressed as mean value ± standard deviation (n = 3) RESULTS Mauritian exotic fruits had widely different free radical-scavenging capacities ranging from to 47 µmol TEAC g−1 fresh weight (Fig and Table 2) The highest activities were measured in red (47 ± µmol g−1 ) and yellow (45 ± µmol g−1 ) Chinese guava (Psidium cattleianum) fruits, followed by sweet starfruit (Averrhoa carambola) (17 ± µmol g−1 ) and Antioxidant activities (µmol g-1 fresh weight) A Luximon-Ramma, T Bahorun, A Crozier 60 50 40 30 20 10 10 11 12 13 14 15 16 17 Fruit Number Figure Antioxidant activities in Mauritian exotic fruits as assessed by TEAC (black) and FRAP (grey) assays: 1, red Psidium cattleianum; 2, yellow Psidium cattleianum; 3, sweet Averrhoa carambola; 4, white Psidium guajava; 5, Syzygium cumini; 6, acid Averrhoa carambola; 7, Carica papaya; 8, pink Psidium guajava; 9, Spondias dulcis; 10, Mangifera indica; 11, Litchi chinensis; 12, Euphoria longan; 13, Passiflora edulis; 14, Ananas comosus; 15, Syzygium samarangense; 16, Persea americana; 17, Musa acuminata white guava (Psidium guajava) (17 ± µmol g−1 ) fruits Lower activities were obtained for jamblon (Syzygium cumini) (15 ± µmol g−1 ) and acid starfruit (Averrhoa carambola) (11 ± µmol g−1 ) Fruits such as banana, avocado, passion fruit, longanberry and pineapple had very low TEAC values The FRAP assay showed more or less the same pattern as the Table Total phenolic, flavonoid, proanthocyanidin, vitamin C contents and antioxidant activities as assessed by TEAC and FRAP assays of commonly consumed Mauritian fruits Scientific name Averrhoa carambola Psidium cattleianum Psidium guajava Spondias dulcis Ananas comosus Musa acuminata Persea americana Syzygium samarangense Syzygium cumini Passiflora edulis Mangifera indica Carica papaya Litchi chinensis Euphoria longan Common name Fruit type Flavonoidsb Proanthocyanidinsc Vitamin Cd TEACe 1429 ± 71 2099 ± 104 5638 ± 364 5372 ± 186 1264 ± 60 2473 ± 45 1050 ± 43 479 ± 14 118 ± 242 ± 19 320 ± 14 103 ± 11 148 ± 712 ± 32 308 ± 13 110 ± 21 209 ± 10 183 ± 159 ± 56 ± 21 ± 31 ± 896 ± 23 1321 ± 61 2561 ± 101 2409 ± 89 109 ± 14 263 ± 31 167 ± 13 14 ± 51 ± 7±0 33 ± — 2359 ± 47 Orange 574 ± 107 Maison Rouge 560 ± 21 Exotica 576 ± 41 — 288 ± 17 — 154 ± 23 135 ± 121 ± 17 281 ± 28 376 ± 15 94 ± 79 ± 453 ± 85 12 ± 168 ± 11 208 ± 21 100 ± 109 ± 12 Starfruit Acid Sweet Chinese guava Red Yellow Guava Pink White Hogplum — Pineapple Bourgault Banana Gingeli Avocado — Jamalac — Jamblon Passion fruit Mango Papaya Litchi Longanberry Total phenolicsa 190 ± 15 144 ± 242 ± 15 200 ± 722 ± 1426 ± 26 244 ± 275 ± 8±1 11 ± 151 ± 20 11 ± 17 ± 47 ± 45 ± 7±1 17 ± 6±1 2±1 1±0 2±0 2±0 FRAPf 9±0 22 ± 34 ± 25 ± 8±0 14 ± 7±0 3±0 3±0 1±0 2±0 319 ± 15 ± 16 ± 86 ± 15 ± 3±1 605 ± 15 ± 5±0 929 ± 19 10 ± 2±0 138 ± 15 ± 3±1 266 ± 15 ± 0.3 ± Data expressed as mean value ± standard error (n = 3); gallic acid g−1 fresh weight; quercetin g−1 fresh weight; c µg cyanidin chloride g−1 fresh weight; d µg ascorbic acid g−1 fresh weight; e µmol Trolox g−1 fresh weight; f µmol Fe(II) g−1 fresh weight a µg b µg 498 J Sci Food Agric 83:496–502 (online: 2003) Antioxidant actions of Mauritian exotic fruits TEAC assay, in the following order for the highest antioxidant activities: red Psidium cattleianum > yellow Psidium cattleianum > Syzygium cumini > sweet Averrhoa carambola > white Psidium guajava > acid Averrhoa carambola (Fig 1) However, fruits of Spondias dulcis, Mangifera indica, Litchi chinensis, Ananas comosus and Passiflora edulis exhibited higher antioxidant activities in the FRAP than in the TEAC assay (Fig 1) Both assays showed relatively low antioxidant activities in fruits such as banana, avocado and longanberry Total phenols, proanthocyanidins and flavonoids were determined for all 17 fruit species Total phenolic contents in the fruit extracts varied from 118 ± to 5638 ± 364 µg g−1 fresh weight (Table 2) A striking correlation between total phenolics and antioxidant activity of the fruit extracts was noted (TEAC, r = 0.98, FRAP, r = 0.95) (Table 3) Fruits with the highest phenolic contents—red Psidium cattleianum (5638 ± 364 µg g−1 ), yellow Psidium cattleianum (5372 ± 186 µg g−1 ), sweet Averrhoa carambola (2099 ± 104 µg g−1 ), white Psidium guajava (2473 ± 45 µg g−1 ), Syzygium cumini (2359 ± 47 µg g−1 ) and acid Averrhoa carambola (1429 ± 71 µg g−1 )—had the highest antioxidant potentials in both the TEAC and FRAP assays (Table 2) On the other hand, fruit extracts characterised by low total phenolic levels exhibited poor antioxidant capacities (Table 2) A relatively good correlation was observed between proanthocyanidin content and antioxidant activity of the fruit extracts (TEAC, r = 0.96; FRAP, r = 0.92) (Table 3) The pattern of variation in proanthocyanidin content was similar to that observed for total phenolics, with maximum levels occurring in red (2561 ± 101 µg g−1 ) and yellow (2409 ± 89 µg g−1 ) Psidium cattleianum, sweet Averrhoa carambola (1321 ± 61 µg g−1 ), acid Averrhoa carambola (896 ± 23 µg g−1 ) and Syzygium cumini (453 ± 85 µg g−1 ), which displayed the highest antioxidant capacities (Table 2) The other fruit extracts contained too low amounts of proanthocyanidins to significantly influence the antioxidant activity Flavonoid levels ranged between 21 ± and 712 ± 32 µg g−1 , with the highest amounts being recorded in red Psidium cattleianum (712 ± 32 µg g−1 ), Carica papaya (376 ± 15 µg g−1 ), yellow Psidium cattleianum (308 ± 13 µg g−1 ), Mangifera indica (281 ± 28 µg g−1 ) and white Psidium guajava (209 ± 10 µg g−1 ) (Table 2) Much lower levels of flavonoid derivatives were present in the other fruits Compared Table Correlation coefficients of TEAC and FRAP with respect to total phenolic, total flavonoid, total proanthocyanidin and vitamin C contents of Mauritian fruits as evaluated by linear regression analysis TEAC FRAP Total phenolics Total flavonoids Total proanthocyanidins Vitamin C 0.98 0.95 0.77 0.69 0.96 0.92 0.07 0.04 J Sci Food Agric 83:496–502 (online: 2003) with total phenols and proanthocyanidins, flavonoids appear to exert less effect on the antioxidant potential of the fruits (Table 3) Table indicates that ascorbate content and antioxidant capacity were poorly correlated (TEAC, r = 0.07; FRAP, r = 0.04), since in many cases vitamin C levels were low in the fruits where antioxidant capacity was high (Table 2) Vitamin C contents ranged from ± to 1426 ± 26 µg g−1 , with maximum values observed in white Psidium guajava (1426 ± 26 µg g−1 ), Carica papaya (929 ± 19 µg g−1 ), pink Psidium guajava (722 ± µg g−1 ), Mangifera indica (605 ± 15 µg g−1 ) and Ananas comosus (275 ± µg g−1 ) (Table 2) Relatively lower amounts were found in the other fruits Mauritian banana and avocado were almost devoid of vitamin C (Table 2) DISCUSSION Free radicals, more particularly their excessive production, appear to feature in many human disorders such as cardiovascular disease, diabetes and cancer, all of which have high and increasing incidences and mortality rates in Mauritius.23 As such, dietary antioxidants may have an important role in combating these pathologies through their protective effect against free radical damage to cellular constituents The literature abounds with examples where fruits from temperate regions have been reported to be good sources of natural dietary antioxidants.31 – 33 Data relating to tropical fruits are more limited and in Mauritius there has previously been no investigation of the phenolic and vitamin C contents and antioxidant capacity of commonly consumed local fruits The present study determined the antioxidant capacities of 17 Mauritian fruits and analysed their extracts for compounds, namely total phenolics, proanthocyanidins, flavonoids and vitamin C, that may contribute to this antioxidant activity Total phenolics were measured by the Folin–Ciocalteu assay, which is based on an oxidation–reduction reaction This method determines not only phenolic compounds but also other chemical components such as carotenoids, amino acids, sugars and vitamin C.25,34 Using the 6-dichloroindophenol titrimetric method,28 the phenolic extracts gave a response corresponding to 20% of the vitamin C content measured in fresh homogenised fruit extracts (data not shown) In spite of various precautions taken to limit the interference of lipid-soluble compounds such as carotenoids by repeated washing with dichloromethane, it is obvious that the total phenolic content measured by the Folin–Ciocalteu procedure does not give a full picture of the quantity and quality of the phenolic constituents of the extracts In the light of the above limitations it is perhaps more appropriate to use the term Folin–Ciocalteu index rather than total phenolics Nevertheless, this widely used method provides a rapid and useful overall evaluation of the phenolic content of extracts 499 A Luximon-Ramma, T Bahorun, A Crozier Two independent methods, the TEAC and FRAP assays, were used to compare the in vitro free radical-scavenging capacities/reducing powers of fruit extracts The results presented in Table show that Mauritian fruits exhibit a wide range of antioxidant potentials Red and yellow Chinese guava, white and pink guava, sweet and acid starfruit and jamblon exhibited high antioxidant activities in both assays that were associated with high levels of phenolics, of which flavanols, flavones and flavonols were major components This is clearly demonstrated by the linear regression analysis of antioxidant activity against phenolic content (Table 3), which shows a statistically significant correlation for these phenolic groups in all fruits using both the FRAP and TEAC antioxidant assays Some fruits (jamblon, passion fruit, pineapple and banana), however, were found to have higher antioxidant capacities in the FRAP than in the TEAC assay This indicates that for both in vitro and in vivo characterisation of the potency of antioxidants no single method can predict efficacy comprehensively It is interesting to compare the data obtained here for Mauritian exotic fruits with those obtained previously for similar or different types of fruits using the same assays The antioxidant capacities of Mauritian red (47 µmol TEAC g−1 fresh weight) and yellow (45 µmol TEAC g−1 fresh weight) Chinese guava seem to be very close to the antioxidant activity of blueberries (45.9 µmol TEAC g−1 fresh weight), which constitute one of the richest sources of antioxidants studied so far.35 Rubus species (with antioxidant capacities ranging from to 25.3 µmol TEAC g−1 fresh weight), which have been recommended for the improvement of nutritional value through germplasm enhancement programmes,36 have a lower antioxidant potency than the studied Mauritian exotic fruits (1–47 µmol TEAC g−1 fresh weight) In a systematic screening of total antioxidants in dietary plants,37 relatively higher FRAP values for pineapple (10.4 mmol g−1 ) and papaya (6.2 mmol g−1 ) and lower activities for mango (3.2 mmol g−1 ) and banana (2.0 mmol g−1 ) were obtained compared with our data for different cultivars Fruit proanthocyanidin contents were much higher than those of any other phenolic subclass assayed and therefore appear to contribute significantly to the antioxidant capacity of fruits It has been shown that proanthocyanidins, which comprise B dimers and their derivatives and oligomers, are strong antioxidants because of the hydroxyl groups attached to the ring structures.38 – 40 They offer protection against free radical damage, lipoperoxidation, cancer and vascular disorders and inhibit platelet aggregation.41 – 43 Vitamin C does not contribute significantly to the antioxidant potential of Mauritian fruits, as shown by the negative correlations obtained between both TEAC and FRAP antioxidant capacity and vitamin C content (Table 3) This is consistent with examples cited in the literature where vitamin C makes little 500 contribution or does not contribute at all to the total antioxidant capacity of fruits Prior et al 44 reported the influence of ascorbate on the antioxidant capacity of lowbush and highbush blueberries to be as low as 2.3 and 1.5% of the total capacity respectively On the basis of the oxygen radical absorbance capacity (ORAC) antioxidant assay, Kalt et al 45 showed that ascorbate content and antioxidant capacity were negatively correlated (R = −0.80) in lowbush and highbush blueberries, raspberries and strawberries Similarly, Gardner et al 46 found that vitamin C accounted for less than 5% of the antioxidant potential of apple and pineapple juices However, these investigators also reported that vitamin C contributed 65–100% of the antioxidant capacity of beverages derived from citrus fruits It seems likely, therefore, that the overall antioxidant capacity of Mauritian fruits is mainly linked to a high ‘Folin–Ciocalteu index’, with proanthocyanidins making a major contribution It is also most probable that the oxidative potency of phenolic acids47,48 present in fruit extracts, but not assayed here, may contribute to the antioxidant actions of flavonoids49,50 to account for the synergistic total antioxidant effect of Mauritian fruits Numerous reports show similar types of linear relationship between antioxidant activities and phenolic contents Prior et al 44 found a linear correlation between ORAC and anthocyanin or total phenolic content in fruits of Vaccinium species Using the same methodology, Ehlenfeldt and Prior51 showed a relationship between antioxidant activity and phenolic and anthocyanin concentrations in fruit and leaf tissues of highbush blueberry Kalt et al 52 reported that phenolic composition, anthocyanins, and antioxidant capacities in strawberries, raspberries and highbush and lowbush blueberries changed during postharvest storage, and the antioxidant capacity was correlated with the level of phenolics and anthocyanins Deighton et al 36 showed apparent linear relationships between antioxidant activities (assessed by the TEAC and FRAP methods) and total phenolics in a number of domesticated and wild Rubus species The phenolic content/antioxidant activity correlation does not seem to be restricted to fruits, as similar observations have been made for medicinal plants,53 – 55 beverages,56,57 vegetables,58 juices,59 wines60 and fresh and processed edible seaweeds.61 Several cross-sectional surveys in a variety of population groups have been conducted to estimate the daily intake of antioxidants Hertog et al 62 showed that the average daily intake of five flavonoids (quercetin, kaempferol, myricetin, luteolin and apigenin) in the Dutch diet was 23 mg, while it was only 12.9 mg in the US diet A similar investigation found that the average flavonoid daily intake in the US diet was 20.1 mg An earlier study indicated that the total polyphenol daily intake in the USA was close to g.63 For comparison, using our data from the Folin–Ciocalteu and total flavonoid assays, the consumption of 180 and 30 g of red Chinese guava respectively would give the J Sci Food Agric 83:496–502 (online: 2003) Antioxidant actions of Mauritian exotic fruits above total phenolic and flavonoid values Similarly, it is speculated that the dietary needs for vitamin C are met by a minimum intake of 60 mg day−1 for an adult.64 However, a review related to epidemiological studies of antioxidants and disease suggests that a daily intake of 150 mg of vitamin C in association with other vitamins (vitamin E, β-carotene) is linked to a reduced incidence of cancer and cardiovascular disease.65 Interestingly, 105 g of white guava (representing a single whole fruit) corresponds to this daily intake This study shows the potential antioxidant properties of certain Mauritian fruits, notably Psidium cattleianum, Psidium guajava, Averrhoa carambola and Syzygium cumini, that could be used as supplements in a balanced diet within existing nutrition programmes This could prove to be a more effective and economical means of protecting the body against various oxidative stresses than supplementation with individual antioxidants such as vitamin C or α-tocopherol This 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of onions Free Rad Res 28:257–269 (1998) J Sci Food Agric 83:496–502 (online: 2003) ... the other fruits Compared Table Correlation coefficients of TEAC and FRAP with respect to total phenolic, total flavonoid, total proanthocyanidin and vitamin C contents of Mauritian fruits as... Analysis of the phenolic compounds in betel quid J Chinese Agric Chem Soc 31:623–632 (1993) 56 Richelle M, Tavazzi I and Offord E, Comparison of the antioxidant activity of commonly consumed polyphenolic... relationship between antioxidant activities and phenolic contents Prior et al 44 found a linear correlation between ORAC and anthocyanin or total phenolic content in fruits of Vaccinium species Using the