Centella asiatica foliages were exposed to fermentation/oxidation for changing sums of clip: no agitation ( 0 min ) , partial agitation ( 90 min ) and full agitation ( 24 H ) . The chemical composing of the teas was determined and compared with commercial Camellia sinensis teas. The consequences of proximate analysis showed Centella asiatica herbal teas contained significantly higher sums of protein, fat and ash than Camellia sinensis teas. Compared to Camellia sinensis teas, all Centella asiatica tea extract infusions contained significantly more entire free amino acids ( 24.87-54.44 milligram l-glutamic acid equivalent/g ) but significantly less entire free polyoses ( 24.33-31.52 milligram glucose equivalent/g ) and were caffeine free. High vitamin B1, vitamin B2, nicotinic acid and ascorbic acid contents were found in all Centella asiatica teas, but vitamin H was found merely in to the full fermented Centella asiatica tea ( CAFF ) . Color measurings demonstrated that Centella asiatica extracts by and large had lower a ( verdancy ) and B ( yellowness ) values than Camellia sinensis teas. All extracts exhibited low turbidness degrees ( less than 10 % ) , except for CAFF. However, the Centella asiatica teas exhibited significantly lower entire phenoplast ( 3.53-6.22mg gallic acid equivalent/g ) , entire flavonoid ( 1.81-2.54 milligram quercetin equivalent/g ) and entire anthocyanin ( 0.99-1.49mg catechin equivalent/g ) contents than Camellia sinensis teas and therefore had lower antioxidant capacities ( DPPH: 21.86-32.64? m trolox equivalent/g and FRAP: 25.86-43.09? m trolox equivalent/g ) than Camellia sinensis teas. Partially-fermented Centella asiatica ( 90 min ) showed no important alteration in antioxidant belongingss, but its entire free polyose content increased, and it produced the darkest extract.
Keywords: Centella asiatica ; herbal tea ; chemical belongingss ; H2O soluble vitamins ; antioxidant belongingss
In recent old ages, there has been an increased attempt to happen nutrients and drinks with high antioxidant contents and health-promoting belongingss. Herbs traditionally used in common people medical specialty have attracted consumer involvement because of their long historical ingestion and ready acceptableness. Herbal teas or tisanes have gained popularity all over the universe due to their antioxidant activity and aroma ( thought to exercise a calming consequence on the head ) ( 1 ) . Harmonizing to the World Health Organization ( 2 ) , over 80 % of the universe ‘s population relies on mostly plant-based traditional medical specialty for primary health care demands. In add-on, the international herb tea market, which includes herbal teas, is huge and is estimated to turn up to US $ 5 trillion by the twelvemonth 2050 ( 3 ) . The Malayan herb tea market was valued at US $ 3.8 billion in 2002 and is predicted to turn at an one-year rate of 10 to 20 % ( 4 ) .
Most Malaysians are accustomed herbal tea consumers and believe that herbal teas are safe to devour, help in wellness publicity, hike energy degree, prevent diseases and have decorative belongingss ( 5 ) . Herbal teas can be easy prepared from any portion of a works, including the roots, flowers, seeds, berries and bark. The readying of an herbal extract, which may dwell entirely of one or more herbs, is simple and can be performed by agencies of decoction, extract or maceration ( 6 ) .
Centella asiatica ( L. ) Urban, synonym Hydrocotyle asiatica, is locally known as “ pegaga ” and belongs to the works household Apiaceae ( Umbelliferare ) . The herb is good known and is called assorted names all over the universe, including “ gotu goora nut ” , “ Mandukaparni ” , “ Brahmi ” and Indian penn’orth. The herb is native to both tropical and semitropical states such as China, India, South America, Madagascar and Malaysia. Centella asiatica is celebrated in Ayurvedic medical specialty for the intervention of Hansen’s disease, insanity, asthma, ulcers, eczema, skin TB, lesions, tummy achings, arthritis, varicose venas, and high blood force per unit area ; it is besides known as a memory foil ( 7 ) . The major constituents of the herb are triterpenes and polyphenols, which have been reported to suppress colon malignant neoplastic disease cell growing ( 8 ) , elicit neuroprotective effects in a mouse theoretical account of lasting intellectual ischemia ( 9 ) and increase the antioxidant enzymes in lymphoma-bearing mice ( 10 ) . The nutritionary value of Centella asiatica is assuring, as it is rich in carotenoids and vitamins B and C ( 11 ) ; the herb is normally used as porridge for feeding pre-school kids in Sri Lanka in order to battle nutritionary lacks ( 12 ) . The benefits of the herb are going popular among Malaysians, and commercial Centella asiatica cultivars are available in Malaysia. Centella asiatica has besides become an of import medicative herb in international medicative herb trading ( 11 ) .
Surveies have shown that herbal teas may be a promising beginning of antioxidants ( 13 ) . Polyphenols such as flavonoids are normally present in herbs. Catechin is the major flavonoid in Camellia sinensis tea ( 14 ) and is good known for its antioxidant belongingss. In Centella asiatica, quercetin and kampferol are present as major antioxidants ( 15 ) . The phenolic hydroxyl group in flavonoids is found to be a strong antioxidant capable of efficaciously scavenging reactive O species ( 16 ) .
Centella asiatica is available on the market in the signifier of tea, soft drinks and sirup. The tea is prepared by simple drying and normally assorted with black tea to accomplish a more xanthous extract. The natural presence of vallerin in Centella asiatica contributes to its acrimonious gustatory sensation ( 7 ) and is non ever acceptable to consumers. However, old surveies have shown that the agitation procedure enhances the quality of herbal tea in footings of coloring material, spirit and gustatory sensation ( 17 ) . As there is a famine of information on the usage of fermented Centella asiatica teas in drink production, the chief aim of this research was to research the feasibleness of Centella asiatica as an herbal tea produced by three types of agitation: no agitation ( CANF ) , partial agitation ( CAPF ) and full agitation ( CAFF ) . The chemical belongingss, H2O soluble vitamin content, centripetal belongingss ( coloring material and turbidness ) and antioxidant capacity of the merchandises were studied and compared with commercial Camellia sinensis teas: green tea ( GT ) , oolong tea ( OT ) and black tea ( BT ) .
MATERIALS AND METHODS
Plants, stuffs and chemicals. Fresh Centella asiatica was obtained from a local moisture market in Penang, Malaysia. Commercial Camellia sinensis teas were bought from a local market. Folin-Ciocalteu ‘s phenol reagent, Na carbonate, aluminum chloride, Na hydrated oxide, caffeine, Fe ( III ) chloride and phenol were purchased from Merck ( Darmstadt, Germany ) . Gallic acid, Na nitrite, quercetin, vanillin, DPPH ( 1,1-diphenyl-2-picrylhydrazyl ) group, TPTZ ( 2,4,6-tripyridyl-s-triazine ) , ninhydrin, DL-panthenol, nicotinamide, vitamin B6, vitamin H and ascorbic acid were purchased from Sigma-Aldrich ( St. Louis, MO. , USA ) . All other chemicals used were of analytical class.
Preparation of Centella asiatica leaves. Centella asiatica foliages were washed under running tap H2O. The cleaned foliages were withered in a locally obtained forced air oven at 30 oC for 2 h. The shriveled foliages were used to fix three sorts of tea drinks.
Non-fermented ( unrefined ) Centella asiatica ( CANF ) tea. The shriveled foliages were dried in a hot air oven at 100 oC until the wet content was less than 6.5 % . The dried foliages were kept in an air tight container.
Partially-fermented ( CAPF ) and fully-fermented ( processed ) ( CAFF ) Centella asiatica tea. The shriveled foliages were manually twisted and torn for 20 min. The bent foliages were allowed to undergo partial agitation for 90 min. For CAFF, a similar process was repeated, but the agitation clip was prolonged to 24 h. The fermented foliages were dried in a hot air oven at 100 oC until the wet content was less than 6.5 % . The dried affair was kept in an air tight container.
Tea extract readying. For all experiments, 1 g of tea foliages was weighed into a beaker. Hot distilled H2O ( 100 milliliter ) was so added and allowed to inculcate the foliages for 10 min. The extracts were filtered through Whatman filter paper No. 1 anterior to analysis.
Proximate analysis. Determination of the wet, petroleum protein, crude fat and rough ash contents were performed harmonizing to the AOAC method ( 18 ) . The protein transition factor used was 6.25.
Determination of entire free amino acids. The entire free amino acids were determined utilizing the method described by Yao et Al. ( 19 ) . Tea extracts ( 1 milliliter ) , 0.5 milliliter of phosphate buffer solution and 0.5 milliliter of 2 % ninhydrin solution incorporating 0.8 mg/mL of Sn chloride were placed into a 25-mL volumetric flask. The mixture in the volumetric flask was so heated in a boiling H2O bath for 15 min. The flask was rapidly cooled down, and the volume was adjusted to 25 milliliter with distilled H2O. After the solution was left standing for 10 min, the ensuing bluish-purple merchandises were read at 570 nanometers utilizing a spectrophotometer ( Shimadzu UV 1240 ) . Consequences were expressed as mg L-glutamic acid equivalent/100 milliliter extract. The measuring was performed in triplicate.
Determination of entire free polyoses. The polyose content was determined by the phenol-sulphuric colourimetric method ( 20 ) . Tea extracts ( 0.5 milliliter ) and 0.6 milliliter of 5 % phenol solution were added into each trial tubing, followed by 0.3 milliliters of concentrated sulfuric acid. Each tubing was assorted good and kept at room temperature for 30 min. The ensuing dark brown solution was measured at 490 nanometers utilizing a spectrophotometer ( Shimadzu UV 1240 ) . Consequences were expressed as milligram glucose equivalent/100 milliliter extract. Measurements were performed in triplicate.
Water soluble vitamin finding
Vitamin B finding utilizing LC/MS. An Agilent LC-MS system 1100 ( USA ) was equipped with a binary pump, degasser, wellplate sampling station and thermostatted column compartment straight connected with a positive ESI mass spectrometer system. The optimisation measure was carried out in flow injection manner utilizing a scan scope of m/z 100-900. The separation was performed on a ZORBAX RRHT SB-Aq ( 100 – 3.0 millimeter, 1.8? m ) with a nomadic stage of ( A ) 20 mM ammonium formate and 0.1 % formic acid in H2O and ( B ) 20 mM ammonium formate and 0.1 % formic acid in methyl alcohol. The gradient elution was programmed as follows: 0-8min, 10 % B ; 8-8.1min, 55 % B ; 8.1-10min, 10 % B at a flow rate of 0.5mL/min with an injection volume of 10? L. Nitrogen gas was used as the nebulising gas ( 30 psig ) and as the drying gas ( 10 L/ min ) . The drying temperature was kept at 350 oC. The capillary issue was 1850 V.
Vitamin C finding utilizing HPLC. Tea extracts ( 10 mL each ) were extracted utilizing an equal volume of 4.5 % ( w/v ) metaphosphoric acerb solution. Samples were filtered through a 0.45-µm membrane filter in aliquots of 20 µL for each tea extract. A Jacob HPLC system ( Jasco, Tokyo, Japan ) equipped with a Jasco PU-2080 Plus Intelligent HPLC Pump, a Jasco AS-2055 Plus Intelligent Sampler, a Jasco UV-2077 PLUS 4- ? Intelligent UV/Vis sensor and a Jasco ChromNAV version 1.11.02 ( Build 4 ) was used. The separation was performed with a Hypersil ODS C18 column ( 250-4.6 millimeter, 5? m ) ( Thermo Scientific, Waltham, MA, USA ) fitted with a Hypersil ODS guard column. The deionised H2O nomadic stage was adjusted with metaphosphoric acid to pH 2.2 at a flow rate of 1.0 mL/min and detected at 276 nanometers ( 21 ) . Consequences were expressed as milligram ascorbic acid/100 mL extract.
Caffeine finding utilizing HPLC. The tea extracts were diluted with deionised H2O and filtered through a 0.45-µm membrane filter and injected into a Jasco HPLC system ( Jasco, Tokyo, Japan ) . The separation was performed on a Hypersil ODS C18 column ( 250-4.6 millimeter, 5? m ) ( Thermo Scientific, Waltham, MA, USA ) fitted with a Hypersil ODS guard column incorporating a nomadic stage of 25 methanol:75 deionised H2O at a flow rate of 1.0 mL/min and detected at 276 nanometers. Consequences were expressed as milligram caffeine/100 milliliter extract.
Coloring material measurings. A Konica Minolta spectrophotometer CM-3500d ( Minolta, Kyoto, Japan ) with illuminant D65 was used to mensurate the CIE L* , a* and b* color infinite of tea extracts ( L* [ elation ( 0 = black, 100 = white ) ] , a* ( -a = verdancy, +a = inflammation ) and b* ( -b = blueness, +b = yellowness ) ) . Consequences were obtained utilizing SpectraMagic™ computing machine package version 3.61 G ( Cyber Chrome, Inc. , Minolta Co. Ltd ) .
Turbidity. The turbidness of tea extracts was measured harmonizing to the method described by Harboune et Al. ( 22 ) utilizing a spectrophotometer ( Shimadzu UV 1240 ) at 400 nanometer. The per centum transmission ( T % ) was recorded, and ( 100 -T % ) was used as a step of turbidness.
Entire phenolic content ( TPC ) . The entire phenolic content of each tea extract was measured utilizing the method described by Kahkonen et Al. ( 23 ) . The tea extract ( 3 milliliter ) was added to 1.5 milliliters of Folin-Ciocalteu ‘s phenol reagent ( 10 % v/v ) and allowed to respond for 5 min. Next, 1.2 milliliter of 7.5 % w/v Na carbonate was added to the reaction mixture and incubated for 30 min. The ensuing bluish composite was measured at 765 nanometer, and TPC was expressed as milligram Gallic acid equivalents ( GAE ) /100 mL extract. Measurements were performed in triplicate.
Entire flavonoid content ( TFC ) . Entire flavonoid content ( TFC ) was assayed as described by Zhishen et Al. ( 24 ) . In brief, 0.5 milliliter of tea extract was assorted with 2 milliliter of distilled H2O and 0.15 milliliter of 20 % w/v Na nitrite and left to stand for 5 min. Then, 0.3 milliliter of 10 % w/v aluminum chloride was added to this mixture. After 6 min, 2 milliliter of 1M Na hydrated oxide and 0.2 milliliter of distilled H2O were added. The optical density was read at 510 nanometer. Quercetin was used as the criterion for the standardization curve due to its high concentration in Centella asiatica ( 15 ) . The consequences were expressed as milligram quercetin equivalents ( QE ) /100 mL extract ; measurings were performed in triplicate.
Entire anthocyanidin content ( TAC ) . The entire anthocyanidin content of the tea extracts was measured utilizing the method described by Sun et Al. ( 25 ) . First, 2.5 milliliter of 1 % ( w/v ) vanillin in methyl alcohol and 2.5 milliliter of 9.0 N hydrochloric acid in methyl alcohol were added to 1 milliliter of tea extract. After incubation at 30 oC for 20 min, the optical density was measured at 500 nanometers utilizing a spectrophotometer ( Shimadzu UV 1240 ) and expressed as milligram catechine equivalents ( CE ) /100 mL extract. Measurements were performed in quintuplicate.
DPPH ( 1,1-diphenyl-2-picrylhydrazyl ) free extremist scavenging activity. The DPPH free extremist scavenging activity of each tea extract was determined harmonizing to the method described by Leong and Shui ( 26 ) . A 0.1 mM solution of DPPH in methyl alcohol was prepared. An aliquot of 0.1 milliliter of tea extract was added to 2.9 milliliter of methanolic DPPH solution and kept in the dark for 30 min. Absorbance was assayed at 517 nanometers utilizing a spectrophotometer ( Shimadzu UV 1240 ) . Trolox solution was used to execute the standardization curves. Consequences were expressed as? mol Trolox equivalents/100 mL extract. The measuring was performed in triplicate.
Ferric cut downing antioxidant potency ( FRAP ) assay. The ability to cut down ferrous ions was measured harmonizing to the method described by Benzie and Strain ( 27 ) . The FRAP reagent was prepared utilizing 300 mM Na ethanoate buffer at pH 3.6, 20 millimeter Fe chloride and 10 mM 2,4,6-tripyridyl-s-triazine dissolved in 40 millimeters hydrochloric acid at a ratio of 10:1:1 ( V: V: V ) . The reagent was incubated in a H2O bath at 37 & A ; deg ; C for 5 min before usage. The initial reading of the reagent was measured at 593 nanometers utilizing a Shimadzu UV 1240 spectrophotometer. An aliquot of 0.1 milliliter of tea extract was so added to 2.9 milliliter of FRAP reagent and kept in the dark for 30 min. Trolox solution was used to make the standardization curves. Consequences were expressed as? mol Trolox equivalents/100 mL extract. Measurements were performed in triplicate.
Statisticss. Experimental informations were analysed utilizing Excel 2007 ( Microsoft Inc. ) and Statistical Package for the Social Sciences ( SPSS ) 17.0 for Windows® ( SPSS Inc. ) . A one-way ANOVA process followed by a Duncan trial was used to find the important difference ( p & A ; lt ; 0.05 ) between intervention agencies. A Pearson correlativity analysis was performed to find the correlationship between the polyphenols and the antioxidant capacity of tea extracts.
RESULTS AND DISCUSSION
Three types of Centella asiatica teas ( CANF, CAPF and CAFF ) were successfully prepared in this survey. The tea extracts were xanthous, as shown in Figure 1.
Chemical belongingss of Centella asiatica and Camellia sinensis teas. Controling wet content is an of import factor in tea saving, peculiarly for the suppression of microbic growing. Owuor ( 28 ) suggests that the wet content of tea merchandises should be below 6.5 % . However, tea leaves with a wet content of 2.5 % or less may grounds a ‘smoky ‘ gustatory sensation ( 28 ) . Based on the consequences obtained ( Table 1 ) , the wet contents of CANF, CAPF and CAFF were 6.42, 6.41 and 6.42 % , severally ; for the three types of Camellia sinensis teas, GT, OT and BT, the wet contents were 6.13, 6.49 and 7.47 % , severally. All the teas analysed fell within the suggested bound, with the exclusion of BT.
There was no important difference observed in all types of Centella asiatica teas during protein analysis. The protein contents of Centella asiatica teas were significantly higher than those of Camellia sinensis teas. The protein content remained changeless in all Centella asiatica teas. This was in conformity with the consequences of Tsai et Al. ( 29 ) , who reported that the N content of tea foliage was non affected by reaping and agitation procedure. Yu et Al. ( 30 ) found that petroleum tea proteins contribute to antioxidant activity. A similar tendency was found for ash contents, which remained unchanged in the three samples ( CANF, CAPF, and CAFF ) . This may be due to the stableness of minerals present in ash, as the temperature used for drying was 100 oC. The fat content of CANF tea was significantly higher than CAPF and CAFF teas. The fat content of all Centella asiatica teas was besides significantly higher than that of Camellia sinensis teas. The fat content reduced with agitation clip, which could hold been due to the release of volatile fat content from the samples during agitation.
Free amino acid content is regarded as an of import standard for tea quality confidence and contributes to overall quality in footings of gustatory sensation, spirit and coloring material ( 19 ) . In CANF and CAPF tea extracts, the entire free amino acid released showed no important alteration but was significantly higher than that released by CAFF tea and Camellia sinensis teas. There were no important differences for all Camellia sinensis teas. The dramatic lessening in entire free amino acid content in CAFF may hold been due to the dislocation of protein during the 24-h agitation clip ( 19 ) . GT had the highest entire free polyose content, followed by OT and BT. These contents were significantly higher than those of CANF and CAFF. However, the polyose content of CAPF was non found to be significantly different from that of OT. However, it was significantly higher than that of BT. Polysaccharides in GT were found to do antioxidant activity in a DPPH check, but their part was less than that of polyphenol and protein ( 30 ) .
No caffeine was found in any Centella asiatica tea. In contrast, the caffeine contents in GT, OT and BT were 21.29, 12.72 and 24.35 mg/100mL, severally. This indicates that Centella asiatica teas possess great possible for the turning caffeine-free tea market. Recently, decaffeination has become popular for understating caffeine content in assorted beginnings, including tea and java. The caffeine content in drinks should be minimised due to caffeine-related side effects, including anxiousness, sickness, jumpiness, jitteriness, a lessening in bosom rate and an addition blood force per unit area and the hazard of cardiovascular disease ( 31 ) .
Water-soluble vitamins. Vitamins are organic compounds present in hint sums in our diet. Individual vitamins have specific maps to advance wellness and life. The sum of water-soluble B and C vitamins present in tea extracts was determined. Vitamin B is made up of a complex group and consists of eight vitamins: vitamin B1 ( vitamin B1 ) , B2 ( vitamin B2 ) , B3 ( nicotinic acid ) , B5 ( pantothenic acid ) , vitamin B6 ( vitamin B6 ) , B7 ( vitamin H ) , B9 ( folic acid ) and vitamin B12 ( cyanocobalamine ) .
The sums of H2O soluble vitamins in Centella asiatica and Camellia sinensis teas are shown in Table 2. The sum of vitamin B1 in Centella asiatica teas was significantly higher than in GT. However, vitamin B1 was non detected in OT or BT. CAPF had a significantly higher sum of vitamin B1 than CAFF and CANF. Centella asiatica teas besides contained significantly more riboflavin than Camellia sinensis teas. There was no important difference between GT and OT, and both teas had a significantly higher vitamin B2 content than BT. Niacin was the prevailing B-vitamin type nowadays in both tea types ( Centella asiatica and Centella sinensis ) . Niacin content was found to diminish along with agitation clip. CANF exhibited the highest niacin content ( 1179.85 µg/100 milliliter ) ; niacin contents were 786.78 and 269.16 µg/100 milliliter in CAPF and CAFF, severally. At the same clip, CANF and CAPF had higher nicotinic acid content than GT, OT and BT. The vitamin B6 content in both tea types increased with agitation clip. Camellia sinensis teas were shown to hold a higher vitamin B6 content than CANF and CAPF. The pyridoxine content of CAFF was non significantly different from that of BT, and it was higher than those of GT and OT. Biotin was found merely in CAFF. Pantothenic acid, folic acid and vitamin B12 were non detected in any of the tea extracts. The absence of folic acid may be due to its sensitiveness to sunlight, air, visible radiation and the heat from the boiling H2O ( 32 ) . Vitamin B12 ( cyanocobalamine ) was reported as non present in black teas ( 33 ) . The high concentration of vitamin B1, vitamin B2 and pyridoxine nowadays in Centella asiatica teas, particularly CAPF, suggested that it is a possible isotonic or energy drink.
The sum of vitamin C or ascorbic acid in Centella asiatica teas was by and large higher than in Camellia sinensis teas ; CANF had the highest sum. Ascorbic acid was found to diminish with agitation grade, bespeaking that ascorbic acid oxidised during agitation. Similar consequences were besides shown by Camellia sinensis teas.
Colour and turbidness. Tea coloring material and turbidness are of import centripetal qualities. The CIE Lab and turbidness values for Centella asiatica and Camellia sinensis tea extracts are given in Table 3. The L value decreased ( from 99.42 to 98.38 ) with the grade of agitation in Centella asiatica teas. A similar tendency was found in Camellia sinensis teas. The L values showed that the extracts of both major tea types were bright and clear. The light-green value ( -a ) of GT and BT was significantly higher than all the Centella asiatica teas, although the -a of CANF was higher than that of OT. However, the B values of all the Camellia sinensis teas were greater than those of the Centella asiatica teas. This implies that Camellia sinensis teas were darker than Centella asiatica teas. In Centella asiatica teas, agitation significantly improved the inflammation and yellowness of the extracts.
Turbidity is the optical belongings that describes the sprinkling and soaking up of visible radiation as it travels through a tea extract, doing the extract expression cloudy or smoky ( 34 ) . The turbidness values of the three types of Camellia sinensis teas were by and large lower than Centella asiatica teas, except for that of CANF, which was significantly lower than that of OT and non significantly different from that of GT and BT. In Centella asiatica teas, turbidness increased with agitation clip with the undermentioned tendency: CANF & A ; lt ; CAPF & A ; lt ; CAFF. Results showed that the turbidness values of both tea types were by and large lower than 10 % , bespeaking a low degree of turbidness. However, CAFF exhibited a high degree of turbidness. The dislocation of compounds in foliages during agitation likely allowed these compounds to spread easy, hence increasing the turbidness value of the extract. A high degree of turbidness in drinks is known to diminish their aesthetic value, as mentioned by Harbourne et Al ( 22 ) .
Antioxidant activity. The TPC, TFC and TAC of Centella asiatica and Camellia sinensis extracts were determined and are given in Figure 2. Polyphenols are aromatic secondary metabolites widely found in herbs and associated with coloring material, centripetal qualities, nutritionary and antioxidant belongingss of nutrient ( 35 ) . All Camellia sinensis teas had higher entire polyphenol contents than Centella asiatica teas. BT had the highest TPC, followed by GT and OT, so CANF, CAPF and CAFF. There was no important difference between the TPCs of CANF and CAPF, but both were significantly higher than that of CAFF. This suggests that drawn-out agitation clip broke down the polyphenols in Centella asiatica teas. Teas with a high TPC besides exhibited high TFC and TAC values. However, BT had a higher TPC than GT but had a lower TAC than GT. Herbal teas contain no caffeine and hence have lower TPC contents than Camellia sinensis teas ( 1 ) . Furthermore, the Camellia sinensis teas besides exhibited high polyphenol contents ( 17-25 % dry weight ) contributed chiefly by catechin, theaflavins, thearubigins and theabrownins. About 45 % of these tea components can be infused into hot H2O ( 14 )
The consequences of antioxidant activities of tea extracts are shown in Figure 3. In order to obtain a dependable consequence, two antioxidant checks, a DPPH free extremist scavenging check and a FRAP check, were used to find the antioxidant activities of tea extracts. DPPH checks are easy, rapid, consistent and widely used for the finding of primary antioxidant activity in herb infusions ( 36 ) . The DPPH is stable at room temperature and produces a violet solution in methyl alcohol. The check is based on the stain of DPPH, which is reduced by the antioxidant nowadays. FRAP assays mensurate the ability of an antioxidant to cut down the ferric-TPTZ ( Fe ( III ) -TPTZ ) composite to blue ferrous-TPTZ ( Fe ( II ) -TPTZ ) composite at low pH ( 27 ) . The check is besides simple, rapid, cheap and extremely consistent ( 37 ) . The Trolox equivalent antioxidant capacity ( TEAC ) was used as the antioxidant parametric quantity and expressed as Trolox equivalent/100 milliliter of tea extract. The TEAC is a more meaningful and descriptive look than checks that report antioxidant activity as the per centum lessening in optical density. The consequences besides provide a direct comparing of the antioxidant activity with Trolox and let comparings to be made with other herbal teas examined by other research workers ( 36 ) .
Infusions that contain a high sum of TPC besides by and large exhibit high antioxidant activity. In our survey, all Camellia sinensis teas with high TPC values showed high antioxidant activities. GT had the highest TEACDPPH value, followed by BT and OT, so CANF, CAPF and CAFF. A similar tendency was besides demonstrated in TEACFRAP. The higher antioxidant activity of GT in comparing with other teas, including OT and BT, was likely due to its high antocyanin content ( 65.62 mg/100 milliliter extract ) . These consequences are in conformity with the findings of Aoshima et Al. and Atoui et Al. ( 1, 13 ) , who reported that green and black teas have higher antioxidant activity rates than herbal teas like sage, batch, camomile, gingko and Mentha piperita. Furthermore, the high caffeine content of Camellia sinensis contributed to a higher TEAC. The antioxidant ability of caffeine was reported to be higher than ascorbic acid and displayed a strong ability to scavenge the hydroxyl extremist and singlet O at a changeless rate of 7.3•109 M-1s-1 and 2.9•107 M-1s-1, severally ( 38 ) . The high sum of catechin derivative nowadays in Camellia sinensis besides contributed to the high rate of antioxidant activity ( 14 ) .
Correlation survey of polyphenols and antioxidant capacity. A correlativity analysis was performed to find the correlativity between polyphenol content and the antioxidant capacity of tea extracts. A strong relationship between entire phenolic content and entire flavanoid content ( r=0.971 ) showed that flavonoids were the major polyphenols nowadays in both types of teas compared to antocyanin ( r=0.868 ) . Polyphenols are a complex group that consists chiefly of flavonoids, phenolic acids and hydroxycinnamic acids. The major polyphenols in Camellia sinensis are catechine and its derived functions ( 14 ) , and quercetin and kaempferol in Centella asiatica ( 15 ) are compounds from flavonoids. As such, polyphenol type showed a clear relationship with TEACDPPH ; a high correlativity was found between TEACDPPH and TPC ( r=0.914 ) , followed by TFC ( r=0.830 ) and TAC ( r=0.769 ) . A similar tendency was apparent regarding polyphenols and TEACFRAP. The phenolic hydroxyl group in flavonoids was found to be a strong antioxidant capable of efficaciously scavenging reactive O species ( 16 ) . Furthermore, a strong correlativity was observed in TEACDPPH and TEACFRAP. The strong correlativity between TEACDPPH and TEACFRAP in comestible tropical workss has besides been reported by Wong et Al. ( 36 ) . This indicated that compounds able to cut down DPPH groups are besides capable of cut downing ferrous ions.
The present survey showed that Camellia sinensis teas have TPC, TFC, TAC and antioxidant belongingss superior to those of Centella asiatica teas. However, the CANF and CAPF possess great possible as herbal teas as a consequence of their higher physiochemical belongings values, soluble vitamin contents and deficiency of caffeine when compared to Camellia sinensis teas. CAPF exhibited no important difference in antioxidant belongingss but had a higher free polysaccharide entire and extract yellowness compared to CANF. However, drawn-out agitation ( full agitation ) inverted these effects.
This work was supported by a Research University ( RU ) Grant from Universiti Sains Malaysia ( 1001/PTEK IND/815040 ) and a USM Fellowship.
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