In-Vitro Evaluation of Antioxidant Potential of Colocasia esculenta Corms
Swati U. Kolhe1, Swapnil S. Lad2*
1Head and Assistant Professor, Department of Pharmacology,
AISSMS College of Pharmacy, Pune - 411001, Maharashtra, India.
2M. Pharm, Research Scholar, Department of Pharmacology,
AISSMS College of Pharmacy, Pune - 411001, Maharashtra, India.
*Corresponding Author E-mail: ladswapnil6995@gmail.com
ABSTRACT:
Introduction: Colocasia esculenta Linn (family: Araceae; synonym: Arum esculentum Linn; Taro) is one of the most important tubers crops worldwide and has been employed for medicinal applications for a significant period. Traditionally, in Indian and Chinese medicine, taro is utilized for many years for medicinal applications such as hypoglycaemic, antifungal, antimicrobial, hepatoprotective, and nervine tonic Taking into consideration the traditional claims, C. esculenta has the potential to be a useful for antioxidant activity. With this perspective in mind, the current research aimed to investigate the antioxidant potential of C. esculenta corms. Method: In vitro antioxidant activity aqueous extract of C. esculenta corms was studied by DPPH method. Ascorbic acid was used as a reference standard. The absorbance of various concentrations of corm extract and ascorbic acid were measured by using UV–Visible Spectrophotometer and the percent radical scavenging activity (% RSA) of the DPPH free radical was measured. Results: The Radical scavenging activity of corm extract of C. esculenta at 400μg/mL was found to be 80.33% at absorbance 0.142. The IC50 value of C. esculenta was found to be 120.16μg/mL which was calculated by using y = 0.0952x+38.56 equation. The Radical scavenging activity of Ascorbic acid at 400μg/ml was found to be 87.67% at absorbance 0.089. The IC50 value of Ascorbic acidwas found to be 28.05μg/mL which was calculated by using y = 0.091x+47.43 equation. Conclusion: Our study indicates that the corm extract has the potential as an antioxidant agent, possibly inhibiting DPPH, when compared with standard ascorbic acid. However, the chemical constituents present in the extract such as saponins, steroids, carbohydrates, glycosides, tannins, flavonoids and proteins may be responsible for such activity.
KEYWORDS: Antioxidant, Colocasia, Corms, Dpph, Absorbance.
INTRODUCTION:
Medicinal plants have been widely utilised for medicinal applications since ancient times1,2. The presence of various compounds in fruits, flowers, and corms including phenolic compounds such as phenolic acids, flavonoids, and tannins, nitrogen compounds like alkaloids and amines, as well as vitamins, and terpenoids, is responsible for their beneficial effects. These substances exhibit strong antioxidant activity, contributing to their ability to counter oxidative stress by scavenging reactive species through hydrogen donation3–5. This action helps to prevent the potential damage that these species could cause to cells and other biological components6. In this sense, there is great interest in finding natural antioxidants from plant materials, and various extracts and isolated compounds have been investigated for their antioxidant activity, using different methods7,8.
A common vegetable in the Indian traditional food system is Colocasia esculenta Linn (C. esculenta) (family: Araceae; synonym: Arum esculentum Linn; Taro9–13. Taro is one of the most important tuber crops worldwide and has been employed for medicinal applications for a significant period. In Chinese medicine, taro can be utilized for many years for medicinal applications14. The pharmacological properties of this plant include hypoglycaemic15, antifungal16, anti-inflammatory17, anti-lipid peroxidative18, antimicrobial19, hepatoprotective20, antihyperlipidemic21 and nervine tonic1,22.
According to studies done on diabetic rats, the corms of this plant have the potential to lower hyperlipidaemia. The corms of C. esculenta are a good source of fibre, vitamin C, B1, B2, and B3, as well as digestible protein and glucose. In the aqueous extract of C. esculenta corms, preliminary phytochemical examination found the presence of proteins, tannins, flavonoids, steroids, glycosides, polysaccharides, and saponins23–25.
Taking into consideration the traditional claims and the reported pharmacological actions, C. esculenta, has the potential to be a useful for antioxidant activity. With this perspective in mind, the current research aimed to investigate the antioxidant potential of C. esculenta corms.
MATERIALS AND METHODS:
Plant materials:
The Corms of Colocasia esculenta were collected from local areas of Raigad, Maharashtra, India. The plant was botanically identified and authenticated at M/s. Shamantak Enterprises Pune, Maharashtra, India.
Preparation of aqueous corm extract:
The 3Kg of plant material (Corms of Colocasia esculenta) were washed with water and then air dried at room temperature [(32±2)℃]. The air-dried corms were cut into small pieces and dried under shed for 7 days. The dried small pieces were crushed into coarse powder (1.5Kg). The coarse powder was extracted with Petroleum ether to remove fatty materials and fibers. A residue was extracted with water and filtered. The filtrate is concentrated under vacuum, and 150gm of aqueous corm extract of Colocasia esculenta were collected21.
Drugs and chemicals:
The corm extract (CE) (Batch no. SE/AC/ 2022/03), was purchased from M/s. Shamantak Enterprises Pune, Maharashtra, India. 2,2-diphenyl-1-picrylhydrazyl (DPPH) (Analytical grade, PT. Otto Pharmaceutical Industries, Indonesia), Ascorbic acid (Analytical grade, New Neeta Chemicals, Pune) were used in the present investigation.
Preparation of 0.1mM DPPH (2,2-diphenyl-1-picrylhydrazyl) Stock Solution:
7.88mg of DPPH (molecular weight 394.32g/mol) was weighed, inserted into a 200.0mL volumetric flask, added 50.0mL methanol, shaken until dissolved, diluted with methanol to the marked line, and shaken homogeneously (obtained DPPH stock solution with concentration 0.1mM).
Preparation of 1000μg/mL C. esculenta corm extract Stock Solution
10mg of corm extract of C. esculenta was weighed, inserted into a 10.0mL volumetric flask, added 6.0mL methanol, shaken until dissolved, diluted with methanol to the marked line, and shaken homogeneously (obtainedC. esculenta corm extract stock solution with concentration 100μg/mL).
Preparation of 0.1mM Ascorbic acid Stock Solution:
3.52mg of Ascorbic acid (molecular weight 176.12 g/mL) was weighed, inserted into a 200.0mL volumetric flask, added 50.0mL methanol, shaken until dissolved, diluted with methanol to the marked line, and shaken homogeneously (obtained Ascorbic acid stock solution with concentration 0.1mM).
Experimental protocol:
DPPH assay procedure:
The free radical scavenging capacity of the aqueous extract of corms was determined using DPPH method. It was measured by a decrease in absorbance at 517nm of asolution of coloured DPPH in methanol. A stock solutionof DPPH (200mL; 0.1mM in methanol) was prepared. A stock solution of aqueous corm extract (10 mL; 1000μg/mLin methanol) was prepared. From this solution, 0.2, 0.4, 0.6, 0.8 and 1mL were taken in test tubes and dilutedwith the methanol up to 1 mL, whose concentration was then 200, 400, 600, 800 and 1000 μg/mL respectively. From each test tube, 0.8mL test samplewas taken in different test tubes and 1.2mL of DPPH solution was added, whose concentration was then 80,160, 240, 320 and 400μg/mL, respectively. The prepared concentrations were incubated for 20min at 27℃, the absorbance was taken at 517nm using a spectrophotometer (Shimadzu UV–Visible Spectrophotometer 1780). IC50 was calculated from % inhibition. Ascorbic acid wasused as a reference standard and dissolved in methanol to make the stock solution withthe same concentration of corm extract of C. esculenta. Control sample (DPPH in methanol) was prepared containing the same volume without any extract and reference ascorbic acid. The percent radical scavenging activity (% RSA) of the DPPH free radical was measured using the following equation:
% RSA = {(A control − A sample)/ (A control)} ×100
A control = absorbance of DPPH alone
A sample = absorbance of DPPH along with different concentrations of extracts.
The IC50 of corm extract was calculated according to the following procedure:
The % RSA (y) were plotted against the sample concentration (x) at all five points, and the respective regression line (y = ax+b) was drawn.
RESULTS AND DISCUSSION:
Reactive oxygen species play a pivotal role in the development of various diseases, as their uncontrolled oxidation results from free radical activity. These radicals oxidize all major classes of biomolecules. The resultant products of these oxidative reactions disperse from their initial point of origin, causing systemic harm and significant cellular damage. To counteract this, natural antioxidants within herbs and spices play a crucial role in preventing the harmful effects of oxidative stress. These natural sources are rich in compounds like polyphenols, flavonoids, and phenolics, known for their ability to scavenge free radicals. The efficacy of antioxidants in scavenging DPPH radicals is attributed to their capacity to donate hydrogen atoms. DPPH, a stable free radical, undergoes reduction through the acceptance of an electron or hydrogen radical, transforming into a stable and non-magnetic molecule. The ability of antioxidants to reduce DPPH radicals is measured by the decline in absorbance at 517 nm, indicating their effectiveness as radical scavenging activity26,27.
Regression equation obtained for corm extract, and ascorbic acid were y = 0.0952x + 38.56, and y = 0.0916x + 47.43 respectively (Fig. 1). The determination coefficient (R2) obtained for corm extract, and ascorbic acid were 0.9356, and 0.9428. Good determination coefficient shows the correlation between concentration and scavenging activity. The higher the concentration, stronger the free radical scavenging activity28.
Fig. 1: % RSA VS Concentration of DPPH + Colocasia esculenta and DPPH + Ascorbic acid (Vit. C) at various concentrations
The Radical scavenging activity of corm extract of C. esculenta at 400 μg/mL was found to be 80.33% at absorbance 0.142 (Table 1). The IC50 value of C. esculenta was found to be 120.16 μg/mL which was calculated by using y = 0.0952x + 38.56 equation. The IC 50 value is inhibitory concentration of extract required to inhibit 50% of initial DPPH free radical. The Radical scavenging activity of Ascorbic acid at 400 μg/ml was found to be 87.67% at absorbance 0.089. The IC50 value of Ascorbic acidwas found to be 28.05 μg/mL which was calculated by using y = 0.091x + 47.43 equation.
Table 1: Absorbance and % RSA of DPPH + Colocasia esculenta and DPPH + Ascorbic acid (Vit. C)at various concentrations.
|
Sr. No. |
Sample |
Conc. Of prepared Test Solution (μg/mL) |
|
Vol. of Test Sample (mL) |
Vol. of DPPH (mL) |
Conc. of Test sample in 2 mL (μg/2 mL) |
Conc. of Test sample in 1 mL (μg/mL) |
Absorbance |
% RSA |
|
1 |
Control |
000 |
0.8 mL Test solution was added to 1.2 mL methanolic DPPH, so total vol in each tube = 2 mL |
0.0 |
1.2 |
000 |
00 |
0.722 |
0.00 |
|
2 |
Corm extract of C. esculenta |
200 |
0.8 |
1.2 |
160 |
80 |
0.385 |
46.67 |
|
|
3 |
400 |
0.8 |
1.2 |
320 |
160 |
0.321 |
55.54 |
||
|
4 |
600 |
0.8 |
1.2 |
480 |
240 |
0.288 |
60.11 |
||
|
5 |
800 |
0.8 |
1.2 |
640 |
320 |
0.257 |
64.40 |
||
|
6 |
1000 |
0.8 |
1.2 |
800 |
400 |
0.142 |
80.33 |
||
|
7 |
Ascorbic acid |
200 |
0.8 |
1.2 |
160 |
80 |
0.314 |
56.50 |
|
|
8 |
400 |
0.8 |
1.2 |
320 |
160 |
0.272 |
62.32 |
||
|
9 |
600 |
0.8 |
1.2 |
480 |
240 |
0.236 |
67.31 |
||
|
10 |
800 |
0.8 |
1.2 |
640 |
320 |
0.193 |
73.26 |
||
|
11 |
1000 |
0.8 |
1.2 |
800 |
400 |
0.089 |
87.67 |
Conc.: Concentration, Vol.: volume, and RSA: Radical scavenging activity.
LIMITATIONS AND FUTURE SCOPE:
This study has some limitations that could be addressed in future research. Firstly, the study focused only on the use of a DPPH free radical scavenging assay method to evaluate antioxidant potential. However, there are many other methods available, such as those using ABTS assay, and FRAP assay, which could be used to explore antioxidant activity. Secondly, it is important to note that corm extract contains various phytoconstituents and several other ingredients that may contribute to the observed antioxidant activity. Therefore, future studies could investigate the individual and combined effects of these components to gain a more comprehensive understanding of their potential therapeutic benefits. The primary focus of this study is on exploring the multiple pharmacological activities of C. esculenta, particularly its antioxidant potential.
CONCLUSION:
C. esculenta showed strong antioxidant activity by inhibiting DPPH, when compared with standard ascorbic acid. The results of this study show that the extract can be used as an easily accessible source ofnatural antioxidant. However, the chemical constituents present in the extract such as saponins, steroids, carbohydrates, glycosides, tannins, flavonoids and proteinsmay be responsible for such activity. The phytoconstituents responsible for the antioxidant activity of C. esculenta are currently unidentified. Therefore, it is suggested that activity–guidedisolation study should be performed.
ACKNOWLEDGMENT:
The authors would like to acknowledge AISSMS College of Pharmacy, Pune, for encouragement and guidance.
DECLARATION OF COMPETING INTEREST:
The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
CREDIT AUTHORSHIP CONTRIBUTION STATEMENT
Swapnil S. Lad: Investigation, Writing – original draft, Visualization, Formal analysis. Swati U. Kolhe: Resources, Conceptualization, Supervision.
REFERENCE:
1. Lad SS, Kolhe SU, Devade OA, Patil CN, Nalawade RD, Rode MR. A Review on Medicinal properties of Colocasia esculenta Linn. Research Journal of Pharmacology and Pharmacodynamics. 2023; 15(3): 2321-5836. doi:10.52711/2321-5836.2023.00026
2. Lad SS, Kolhe SU, Devade OA, Patil CN, Nalawade RD, Mansabdar AP. Hyperlipidaemia: A Review of Literature. Research Journal of Pharmacology and Pharmacodynamics. 2023; 15(3): 127-132. doi:10.52711/2321-5836.2023.00023
3. Cai Y, Luo Q, Sun M, Corke H. Antioxidant activity and phenolic compounds of 112 traditional Chinese medicinal plants associated with anticancer. Life Sci. 2004; 74(17): 2157-2184. doi: 10.1016/j.lfs.2003.09.047
4. Djeridane A, Yousfi M, Nadjemi B, Boutassouna D, Stocker P, Vidal N. Antioxidant activity of some algerian medicinal plants extracts containing phenolic compounds. Food Chem. 2006; 97(4): 654-660. doi: 10.1016/j.foodchem.2005.04.028
5. Yang J, Martinson TE, Liu RH. Phytochemical profiles and antioxidant activities of wine grapes. Food Chem. 2009; 116(1): 332-339. doi: 10.1016/j.foodchem.2009.02.021
6. Erkan N. Antioxidant activity and phenolic compounds of fractions from Portulaca oleracea L. Food Chem. 2012; 133(3): 775-781. doi: 10.1016/j.foodchem.2012.01.091
7. Dudonné S, Vitrac X, Coutiére P, Woillez M, Mérillon JM. Comparative study of antioxidant properties and total phenolic content of 30 plant extracts of industrial interest using DPPH, ABTS, FRAP, SOD, and ORAC assays. J Agric Food Chem. 2009; 57(5): 1768-1774. doi:10.1021/jf803011r
8. Moon JK, Shibamoto T. Antioxidant assays for plant and food components. J Agric Food Chem. 2009; 57(5): 1655-1666. doi:10.1021/jf803537k
9. Sharma S, Jan R, Kaur R, Riar CS. Taro (Colocasia esculenta). In: Antioxidants in Vegetables and Nuts - Properties and Health Benefits. Springer Singapore; 2020: 341-353. doi:10.1007/978-981-15-7470-2_18
10. Brown AC, Reitzenstein JE, Liu J, Jadus MR. The anti-cancer effects of poi (Colocasia esculenta) on colonic adenocarcinoma cells in vitro. Phytotherapy Research. 2005; 19(9): 767-771. doi:10.1002/ptr.1712
11. He X, Miyasaka SC, Fitch MM, Zhu YJ. Taro (Colocasia esculenta (L.) Schott). In: Agrobacterium Protocols. Vol 1224. Springer New York; 2015: 97-108. Accessed August 5, 2023. https://link.springer.com/10.1007/978-1-4939-1658-0_9
12. Sp K, Joshi H. The pharmacological importance of Colocasia esculenta Linn: A review. J Pharmacogn Phytochem. 2019; 8(6): 1945-1948. http://www.phytojournal.com
13. Kubal K, Dikwalkar K, Rane A, et al. pharmaceutical approach of Taro (Colocasia esculenta) (AbstractView.aspx? Journal=Asian Journal of Research in Pharmaceutical Sciences. 2023-2036. doi:10.52711/2231-5659.2023.00040
14. Yu JG, Liu P, Duan JA, Tang ZX, Yang Y. Itches - Stimulating compounds from Colocasia esculenta (taro): Bioactive-guided screening and LC-MS/MS identification. Bioorg Med Chem Lett. 2015; 25(20): 4382-4386. doi: 10.1016/j.bmcl.2015.09.023
15. S KN, P CS, S WN, A DT, R P V. Antidiabetic Activity of Ethanol Extract of Colocasia Esculenta Leaves in Alloxan Induced Diabetic Rats. Vol 2.; 2012. www.graphpad.com.
16. Mengane SK. Antifungal activity of the crude extracts of Colocasia esculenta leaves in vitro on plant pathogenic fungi. International Research Journal of Pharmacy. 2015; 6(10): 713-714. doi:10.7897/2230-8407.0610138
17. Agyare C, Boakye YD. Antimicrobial and Anti-Inflammatory Properties of Anchomanesdifformis (Bl.) Engl. and Colocasia esculenta (L.) Schott. Biochem Pharmacol (Los Angel). 2015; 5(1). doi:10.4172/2167-0501.1000201
18. Patil BR, Ageely HM. Anti-lipid peroxidative activity of Colocasia esculenta leaf juice against CCl4 and acetaminophen mediated cell damage. 2011; 2. http://www.bipublication.com
19. Al-Kaf AG, Taj Al-Deen AM, ALhaidari SAA, Al-Hadi FA. Phytochemical analysis and antimicrobial activity of Colocasia esculenta (Taro) medicinal plant leaves used in folk medicine for treatment of wounds and burns in Hufash district AL Mahweet Governorate–Yemen. Universal Journal of Pharmaceutical Research. Published online May 5, 2019. doi:10.22270/ujpr. v4i2.254
20. Nkiruka Chinonyelum A, Peter Uwadiegwu A, Chukwugozie Nwachukwu O, Emmanuel O. Evaluation of Hepatoprotective Activity of Colocasia Esculenta (L. Schott) Leaves on Thioacetamide-Induced Hepatotoxicity in Rats. 2015; 28.
21. Lad SS, Kolhe SU. Evaluation of antihyperlipidemic potential of aqueous corm extract of Colocasia esculenta in experimental model of rats. Pharmacological Research - Modern Chinese Medicine. 2023; 9: 100307. doi: 10.1016/j.prmcm.2023.100307
22. Gupta K, Kumar A, Tomer V, Kumar V, Saini M. Potential of Colocasia leaves in human nutrition: Review on nutritional and phytochemical properties. J Food Biochem. 2019; 43(7). doi:10.1111/jfbc.12878
23. Eleazu CO, Iroaganachi M, Eleazu KC. Ameliorative potentials of cocoyam (Colocasia esculenta L.) and unripe plantain (Musa paradisiaca L.) on the relative tissue weights of streptozotocin-induced diabetic rats. J Diabetes Res. 2013; 2013. doi:10.1155/2013/160964
24. Yadav M, Kushawaha DK, Chatterji S, Watal G. Antihyperglycemic and Antihyperlipidemic Potential of Colocasia esculenta Corms-in vivo. Int J Biol Med Res. 2019; 10(1): 6664-6668. Accessed August 5, 2023. www.biomedscidirect.com
25. Kirti Kubal, Kunal Dikwalkar, Akshay Rane, et al. pharmaceutical approach of Taro (Colocasia esculenta). Asian Journal of Research in Pharmaceutical Sciences. 2023; 13(3): 225-4. doi:10.52711/2231-5659.2023.00040
26. Nariya P, Nariya M, Shukla V, Acharya R, Bhalodia N. In vitro evaluation of antioxidant activity of Cordia dichotoma (Forst f.) bark. AYU (An International Quarterly Journal of Research in Ayurveda). 2013; 34(1):124. doi:10.4103/0974-8520.115451
27. Ghaisas MM, Navghare V V, Takawale AR, Zope VS, Deshpande AD, Vithalrao NV. In-vitro antioxidant activity of Tectona grandis Linn. Pharmacologyonline. 2008; 3: 296-305. Accessed August 10, 2023. https://pharmacologyonline.silae.it/files/archives/2008/vol3/035_Ghaisas.pdf
28. Nerdy N, Manurung K. Spectrophotometric method for antioxidant activity test and total phenolic determination of red dragon fruit leaves and white dragon fruit leaves. Rasayan Journal of Chemistry. 2018; 11(3): 1183-1192. doi:10.31788/RJC.2018.1134018
Received on 04.09.2023 Modified on 12.03.2024
Accepted on 03.07.2024 ©Asian Pharma Press All Right Reserved
Asian J. Res. Pharm. Sci. 2024; 14(3):211-215.
DOI: 10.52711/2231-5659.2024.00034