Last updated: May 12, 2019
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Chapter 5

Compounds from workss can be separated based on their comparative solubilitites by utilizing several of works extraction method such as maceration. First, the works samples were put indoors oven until there is no alterations in weight to let homogeneous drying. The container of the samples inside the oven was wrapped with aluminum foil to forestall the exposure to sunlight. This will cut down the chemical transmutation that might happen due to exposure to UV radiation. The works samples were so land to do the sample more homogeneous every bit good as to increase the surface country of the sample so that the dissolver will hold a better diffusion belongings ( Sarker, Latif, & A ; Gray, 2006 ) . Besides this, the aim of pulverizing the works stuff is to tear its organ, tissue and cell constructions so that the antioxidant compounds are exposed to the extraction dissolver ( Sukhdev, Suman, Gennaro, & A ; Dev, 2008 ) .

The extraction solution were chosed based on their increasing mutual opposition belongings i.e. n-hexane, trichloromethane, propanone, methyl alcohol to determine the extraction of works metabolite since the workss matrices are complex with a scope of secondary metabolites. After extraction, the dissolver was separated from the residuary works through filtration of cheese fabrics and filter paper to obtain more concentrated of works liquid that contain the antioxidant belongings ( Sarker , 2006 ) . The filtrate dissolver is so was evaporated under force per unit area to concentrate the active metabolites that present inside the filtrate dissolver.

The evaporated infusion was further diluted with propanone, methyl alcohol, trichloromethane and n-hexane for each works and were left in the oven under approprite temperature to take the residuary dissolver. Before put inside the oven, these infusions were suspended and diluted in extraction dissolver to convey the feature of water-solubility to the infusions every bit good as to do certain that they are more stable at pH media. These belongingss are of import in most of the in vitro checks ( Liu, 2008 ) .

5.2 Infusions outputs

Extraction output is a quantitative representation of the efficiency of the extraction dissolver to pull out compound from the works ( Silla, Arnau & A ; Tunon, 2001 ) . Extraction output depends on dissolver, temperature, and clip every bit good as the chemical nature of the sample. The same status of clip and temperature, the dissolver used and the chemical belongings of sample are the most critical factors. The extraction solvent itself such as methyl alcohol, propanone, H2O or mixture are another of import facet impacting both extraction output and antioxidant activity of infusions. The extraction outputs of five samples were shown in Table 4.1. The ranking of these five samples in four different dissolvers are different. The behavior of compound stuff towards dissolver were different from each other due to the complexnesss of both the chemical belongingss of dissolvers and the diverse construction and composing of the works compounds. No individual dissolver could pull out all the antioxidants of different mutual opposition and solubility in a individual works. ( Yang, Wang, Ke, Jiang & A ; Ying, 2007 ) .

The output of the infusions was calculated based on a dry weight footing to extinguish the influence of the wet content of the works ( Silla et al. , 2001 ) . From the four infusions, methanol extraction produced the highest sum of extractible compounds followed by propanone extraction and the least are extracted by n-hexane infusion. The extraction ability of methyl alcohol and propanone were really close whereas the n-hexane infusion was merely little in comparative comparison to other dissolvers. This proved that methyl alcohol is an effectual dissolver with good recovery ( Yao, Jiang, Datta, Singanusong, Liu, Duan, et al. , 2004 ) . The higher output of methyl alcohol and propanone show that the soluble compounds in the five workss can be categorised into intermediate and high mutual opposition.

5.3 Assessment of Antioxidant activity

5.3.1 Preliminary rating utilizing TLC-DPPH analysis.

All the works infusion compounds except Brassica oleracea in methyl alcohol were found to exhibit DPPH free groups scavenging activity at different degrees in the rapid showing. The violet coloring material of DPPH quickly faded when it was in contact with antioxidant compounds extracted by different dissolvers. It took 40 to 90 seconds for the extracted works antioxidant compounds to to the full decolor the DPPH violet coloring material background severally. The aa‚¬E?tailingaa‚¬a„? visual aspect on TLC home base is due to the continous burden of sample on the same location that made the petroleum infusion concentrated, and made it to travel like a tail during the procedure. It could be safe to reason that all the extracted workss could function as good antioxidant compounds due to their ability to scavenge the DPPH free groups. The Brassica oleracea in methyl alcohol can non be determined on the TLC home base due to the comparatively high concentration of compounds within the works. High concentration make the works sample to possess a high molecular weight that disable the compound component to go further and go important under the short or long UV visible radiation. On the other manus, the failure of Brassica oleracea compounds in methyl alcohol on TLC home base is due to its high volatile chareteristic that made it to vaporize in a short duaration of clip. DPPH trial on TLC, let to detect a yellow-pale discoloration that is classified as zones of antioxidant activity and brown grey under violet underside. This state of affairs can be concluded that the grey brown discolorations are those that correspond to the alkaloids that can be identified as antioxidant compounds and are inactivated with respect to the DPPH ( Janat, Koffi, Yves, Marc, DjiAA© , Tra, et al. , 2008 ) .

5.3.2 DPPH Radical Scavenging Activity

Harmonizing to Matsuthisakul et Al. ( 2005 ) , The DPPH method was used to mensurate the primary antioxidant activity of the works extracts. This is because, DPPH method is one of the most efficient method for measuring the concentration of extremist scavenging compounds quickly by a concatenation interrupting mechanism. The decrease capableness of DPPH is determined by the lessening in its optical density at 517 nanometers due to the presence of antioxidant compounds. The decolourisation of the violet reaction solution to blanch xanthous hydrazine is stoichiometric with regard to figure of free extremist negatrons captured ( Norshazila et al. , 2010 ) .

In this survey, five workss samples extracted with four different dissolvers were used to gauge the antioxidant activity by mensurating the free extremist scavenging activity of DPPH. In this machinery, ascorbic acid was used as positive control. The scavenging activity of the samples on DPPH was strongly dependent on the concentration of the infusion ( Sawadago, Meda, Lamien, Kiendrebeogo, Guissaou & A ; Nacoulma, 2006 ) . The antioxidant activity of each of the samples was expressed as IC50. If IC50 of a peculiar sample was close to the value of ascorbic acid, so the sample was considered to hold a good extremist scavenging activity. This is because the ascorbic acid is known as powerful antioxidants. The DPPH extremist scavenging activity can besides be expressed as ascorbic acerb equivalent to antioxidant capacity ( AEAC ) ( Banerjee, Chakrabarti, Hazra, Banerjee & A ; Mukherjee, 2008 ) .

In this survey, methyl alcohol infusions showed the highest antioxidant activity by DPPH check followed by propanone. In the methyl alcohol extraction, Abelmoschus esculentus and Nelumbo nucifera extracts showed more than 80 % free extremist scavenging activities at all degree of concentration proposing their high potency as good free extremist scavengers. On the other manus, the IC50 informations in Figure 4.3 showed that most of the trichloromethane and hexane works extracts except Moringa deifera and Brassica oleracea scavenged less than 50 % of DPPH groups even at the highest concentration. Polar dissolver such as methyl alcohol and propanone are those that by and large have higher antioxidant activity. The antioxidant activity shown by the more polar extraction dissolver could be due to the presence of phenolic compounds and flavonoids because they contain an aromatic hydroxyl mediety ( Chaifang & A ; Shifeng, 2009 ) . Generally phenolic compounds with an aromatic ring possess a stronger antioxidant activity than monophenolics ( Gordana, Jasna, Sonja, Vesna, Sinisa & A ; Dragoljub, 2007 ) .

Consequently, methanol infusions was ranked as the best DPPH extremist scavenger followed by propanone, so trichloromethane and eventually n-hexane as the weakest extremist scavenger. These informations correlative good with the work of Norshaila et Al. ( 2010 ) on Malayan Tropical fruits which revealed the weak extremist scavenging activity of n-hexane infusions and the extremely powerful antioxidant activity of methyl alcohol infusions. This is because compounds extracted in non-polar dissolver such as n-hexane obviously lacked of H donating capableness. This signifies that compounds with strongest extremist activity in these five comestible infusions are high mutual opposition workss. However, there are some disadvantages in this method. The major disadvantage would be the usage of non-physiological related group, which does non resemble free groups involved in biological system. Other than that, the optical density of 517 nanometers used in this check causes the intervention of carotenoids. Last, this method is merely applicable to lipotropic antioxidants ( Yu, 2007 ) .

5.3.3 Ferric Thiocyanate Method

The mechanism associated with this method are the same as those involve in the Ferric Oxidation-Xylenol Orange ( FOX ) assay. The difference is that a ferrous ion formed by an oxidizer from a ferric ion is monitored as a thiocyanate composite by a spectrophotometer at 500 nanometer. The repressive consequence toward oxidization from ferric ion to ferric ion by antioxidants is evaluated by supervising the formation of ferrous thiocyanate composite. This check is simple and extremely consistent. One disadvantage of FTC is that if any chemical with UV soaking up about 500 nanometer is present, the consequences are overestimated or non dependable. This is true for any other check utilizing a spectrophotometer ( Joon & A ; Takayuki, 2009 ) .

FTC measures the sum of peroxide generated at the initial phase of linoleic acerb emulsion during incubation. By and large, the optical density will increase over clip, which shows that the autoxidation of linoleic acerb emulsion in the control or sample fraction addition in the peroxide formation. Significantly lower lipid peroxidation activity has been observed in ascorbic acid comparison to other works samples. Different works infusions obtained from different extraction dissolvers exhibited different degree of antioxidant activity within the scope of 63-81 % by the FTC method except for trichloromethane and hexane extracted samples which is less than 60 % . This is may be due to the failure of the non-polar dissolver to pull out out the antioxidant belongings from the works samples.

5.3.4 Thiobarbituric Acid ( TBA ) Test.

5.4 Comparison Analysis between checks

5.4.1 TLC-DPPH analysis with DPPH scavenging activity

5.4.2 FTC analysis and TBA trial comparing