Ravindran, S (2010) In Vitro a Amylase Α Glucosidase Inhibitory and Antioxidant Activities of Benincasa Hispida (Thunb.) Cogn. Fruit and Seed Extracts. Masters thesis, Sri Ramakrishna Institute of Paramedical Sciences, Coimbatore.
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Abstract
The present study was carried out to evaluate the in vitro antidiabetic and antioxidant activities of the fruits and seeds of Benincasa hispida (Thunb) Cogn. The in vitro antidiabetic activity of BHFP and BHSP have been evaluated by measuring its α amylase and α glucosidase inhibitory activities and was compared with the standard drug acarbose, which is suppression of post prandial hyperglycemia. In the light of the result present study indicates that BHFP and BHSP both possess antidiabetic activity and to be specific the BHSP possess more antidiabetic activity than the BHFP. Free radicals are known to play a definite role in the pathological manifestation of diabetes. Antioxidant fights against free radicals by protecting us from various diseases and scavenges the reactive oxygen radicals or protects the antioxidant defense mechanism. Reactive oxygen species (ROS) are capable of damaging biological macromolecules such as DNA, carbohydrates and proteins. ROS is a collective term, which includes not only oxygen radicals (O2˙ and OH˙) but also some non-radical derivatives of oxygen like H2O2, HOCl, and ozone (O3). In addition, antioxidant activity may be regarded as a fundamental property important for life. specific inhibitor of α glucosidase. Acarbose also possess inhibitory action of α amylase. The amount of glucose produced by the action of α glucosidase is estimated by using the enzyme glucosidase and peroxidase in vitro. The α amylase inhibitory activity of the BHFP is lesser when compared to BHSP. However both BHFP and BHSP has lesser inhibition percentage than that of the acarbose. However, the α glucosidase inhibition of the extract was much lesser than the inhibitory action shown by acarbose. The possible mechanism of action of α amylase may be due to the blocking of the starch binding site and α glucosidase inhibition may be due to blockade of the oligosaccharide binding site. Alpha amylase catalyses the hydrolysis of the internal α 1,4 glucosidic linkages in starch and other related polysaccharides which has been the targets for the The in vitro antioxidant activities of the BHFP and BHSP have been evaluated by measuring its scavenging activities by various methods such as DPPH radical scavenging assay, deoxyribose degradation assay, NBT reduction assay to study the superoxide scavenging activity and reducing power ability method to study the total antioxidant capacity. DPPH is a stable free radical at room temperature, which produces a violet solution in ethanol DPPH is widely used to evaluate the free radical scavenging effect of natural antioxidant. DPPH shows a strong absorption band at 517 nm in visible spectrum (deep violet colour). As the electron becomes paired in the presence of free radical scavenging, the absorption vanishes and the resulting discoloration stochiometrically coincides with the number of electrons taken up (Mensor et al., 2001). The bleaching of DPPH absorption is representative of the capacity of the test drugs to scavenge free radicals independently. DPPH radical scavenging activities increased with increasing concentrations of BHFP and BHSP. Based on the mechanism of reduction of DPPH molecule described in the literature, it is correlated with the presence of hydroxyl groups on the antioxidant molecule. We can infer that the very good activity of BHFP and BHSP was probably due to the presence of substance with an available hydroxyl groups. Hydroxyl radicals are the highly reactive radicals which are produced through the Fenton’s reaction in living system. Hydroxyl radicals scavenging activity was quantified by measuring inhibition of the degradation of deoxyribose by free radicals (Guzman et al., 2001). Deoxyribose levels were determined by reaction with thiobarbituric acid. BHFP and BHSP showed a good hydroxyl radical scavenging activity but lesser than standard, quercetin. Superoxide anion radicals were generated enzymatically in vitro by the hypoxanthine and xanthine oxidase system was determined by using NBT reduction assay. Superoxide reduces NBT to form a blue coloured complex formazone which is measured spectrophotometrically. The decrease of absorbance at 560 nm with BHFP and BHSP indicates the consumption of superoxide anion in the reaction mixture (Gulcin et al., 2003). Determination of the mean rate of increase in absorbance over one minute period provides a measure of the extent to which the test fraction is capable of inhibiting NBT reduction by the superoxide anion radical and thus of superoxide scavenging activity. The reductive capabilities of BHFP and BHSP were compared with BHT. For the measurements of the reductive ability, we investigated the Fe3+-Fe2+ transformation in the presence of BHFP and BHSP. The reducing capacity of a compound may serve as a significant indicator of its potential antioxidant activity. However, the antioxidant activity of antioxidants have been attributed to various mechanism, among which are prevention of chain initiation, binding of transition metal ion catalysts, decomposition of peroxides, prevention of continued hydrogen abstraction, reductive capacity and radical scavenging antioxidant activity (Gulcin et al., 2004; Amarowiz et al., 2004). The reducing power of BHFP and BHSP increased with increasing amount of sample. Here the color change occurs from yellow to greenish blue depending upon the reducing power of BHFP and BHSP. Thus from the present investigation, it can be said that the Benincasa hispida (Thunb) Cogn. exhibited remarkable antioxidant property in various in vitro assay systems. In conclusion, there has been a growing interest in the alternative medicine and the therapeutic properties of the natural products derived from plants in the recent years. Based on the evaluation done using the various in vitro assay models it may be concluded that Benincasa hispida (Thunb) Cogn seed extract possess more α amylase and α glucosidase enzyme inhibitory actions than the fruit extract and thus retards glucose absorption and reduces post prandial hyperglycaemia. The antioxidant activity of the plant was proved using various in vitro assay systems. The preliminary chemical tests provided insights into the presence of polyphenolics compounds in the extract. Hence the above stated activities can be attributed due to the presence of these flavonoids. Further studies using in vivo models are necessary to confirm these activities and to explore the exact mechanism by which the plant constituents act.
| Item Type: | Thesis (Masters) |
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| Uncontrolled Keywords: | Vitro a Amylase ; Glucosidase Inhibitory ; Antioxidant Activities ; Benincasa Hispida ; Fruit and Seed Extracts. |
| Subjects: | PHARMACY > Pharmacology |
| Depositing User: | Ravindran C |
| Date Deposited: | 05 Oct 2017 05:20 |
| Last Modified: | 01 Feb 2018 16:57 |
| URI: | http://repository-tnmgrmu.ac.in/id/eprint/3567 |
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