• Numer Alam Central Department of Chemistry, Tribhuvan University, Kirtipur, Kathmandu, Nepal.
  • Khaga raj Sharma Central Department of Chemistry, Tribhuvan University, Kirtipur, Kathmandu, Nepal.


Objectives: The purpose of this research was to estimate the phenolic content, flavonoid content, antioxidant, antibacterial, and α-amylase inhibitory activity of some selected plants such as Anethum sowa, Trigonella foenum-graecum, Lepidium sativum, Cuscuta reflexa, Eclipta alba, Leucas cephalotes, and Tinospora cordifolia collected from Siraha district of Nepal using in vitro studies.

Methods: Methanol extracts of these medicinal plants were prepared by cold percolation method. Preliminary phytochemical screening was performed by color differentiation method. Total phenolic and flavonoid content were estimated by Folin-Ciocalteu reagent method and aluminum chloride colorimetric method. Antioxidant potential was evaluated by 2,2-diphenyl-1-picrylhydrazyl radical scavenging assay. Furthermore, the α-amylase enzyme inhibitory activity was studied using starch as a substrate, pancreatic α-amylase as the enzyme, and acarbose as standard.

Results: Phytochemical screening showed that the plant extracts were found a rich source of secondary metabolites. The phenolic content estimation showed T. foenum-graecum 939.764±0.01, L. sativum 551.63±0.02, A. sowa 306.34±0.06, L. cephalotes 233.19±0.03, T. cordifolia 211.76±0.02, E. alba 202.67±0.02, and C. reflexa Roxb. 145.09±0.09 mg milligram gallic acid equivalent per gram. The flavonoid content estimation showed T. cordifolia 852.07±0.11, L. sativum 553.81±0.05, E. alba 322.13±0.02, A. sowa 329.02±0.05, L. cephalotes 164.93±0.02, and C. reflexa Roxb. 146.37±0.00 mg milligram quercetin equivalent per gram. The antioxidant potential showed by E. alba IC50 33.48±0.82 μg/ml and the values ranged from E. alba 33.48±0.82 to A. sowa 47.62±1.09 μg/ml. The α-amylase inhibitory activity showed by A. sowa 76.78±2.00–E. alba 777.36±9.66 μg/ml. The result of brine shrimp toxicity showed LC50 value >1000 μg/ml. Among the seven plant extracts, only the plant extract of E. alba showed a zone of inhibition 14 mm against Staphylococcus aureus.

Conclusions: The plant extract of T. foenum-graecum showed the highest phenolic content, and T. cordifolia showed the highest flavonoid content. The highest antioxidant potential exhibited by E. alba and the highest α-amylase inhibition activity showed by A. sowa. The plant extract of E. alba showed moderate antibacterial activity against S. aureus. All plant extracts were found non-toxic against brine shrimp larvae although further study is needed to assess its mechanism of action.

Keywords: Antioxidant, α-Amylase, Gallic acid, Quercetin, Plant extract


1. Joshi B, Lekhak S, Sharma A. Antibacterial property of different medicinal plants: Ocimum sanctum, Cinnamomum zeylanicum,Xanthoxylum armatum and Origanum majorana. Kath Univ J Sci 2009;5:143-50.
2. Subedi A, Amatya MP, Shrestha TM, Mishra SK, Pokharel BM. Antioxidant and antibacterial activity of methanolic extract of Machilus odoratissima. Kath Uni J Sci Eng Tech 2012;8:73-80.
3. Gokhale M, Wadhawani M. Antimicrobial activity of secondary metabolites from plants-a review. Int J Pharmacognosy 2015;2:60-5.
4. Sridevi P, Budde S, Neeraja T, Raju BM, Adapa B. Antioxidants and their role in disease management. Int J Med Res Health and Sci 2018;7:175-90.
5. Kamtekar S, Keer V, Patil V. Estimation of phenolic content, flavonoid content, antioxidant and alpha amylase inhibitory activity of marketed polyherbal formulation. J Appl Pharm Sci 2014;4:61-5.
6. Sudha P, Zinjarde SS, Bhargava SY, Kumar AR. Potent ?-amylase inhibitory activity of Indian ayurvedic medicinal plants. BMC Complement Altern Med 2011;11:5.
7. Paul T, Banerjee S. In vitro evaluation of ?-amylase inhibitory activity and antioxidant potential of Pteris vittata L. with special reference to its HPTLC profile. Int J Pharm Bio Sci 2013;4:494-503.
8. Ganesan A. The impact of natural products upon modern drug discovery. Curr Opin Chem Biol 2008;12:306-17.
9. Kasote DM, Katyare SS, Hegde MV, Bae H. Significance of antioxidant potential of plants and its relevance to therapeutic applications. Int J Biol Sci 2015;11:982-91.
10. Mishra LC. Scientific Basis for Ayurvedic Therapies. 1st ed. Boca Raton, USA: CRC Press; 2003. p. 102.
11. Harbone JB. Phytochemical Methods: A Guide to Modern Techniques of Plant Analysis. London, New York: Champman and Hall Ltd.; 1973. p. 279.
12. Jamuna S, Paulsamy S, Karthika K. Screening of in vitro antioxidant activity of methanolic leaf and root extract of Hypochaeris radicata L (Asteraceae). J Appl Pharm Sci 2012;2:149-154.
13. Khan MS, Yusufzai SK, Rafatullah M, Sarjadi MS, Razlan M. Determination of total phenolic content, total flavonoid content and antioxidant activity of various organic crude extracts of Licuala Spinosa Leaves from Sabah, Malaysia. ASM Sci J 2018;11:53-8.
14. Pallab K, Tapan B, Tapas P, Ramen K. Estimation of total flavonoid content (TFC) and antioxidant activities of methanolic whole plant extract of Biophytum sensitivum Linn. J Drug Deliv Ther 2013;3:33-7.
15. Kusano R, Ogawa S, Matsuo Y, Tanaka T, Yazaki Y, Kouno I. ?-Amylase and lipase inhibitory activity and structural characterization of acacia bark proanthocyanidins. J Nat Prod 2011;74:119-28.
16. Cavalieri SJ, Rankin ID, Harbeck RJ, Sautter RL. Manual of antimicrobial susceptibility testing. Am Soc Microbial 2015; ???:???.
17. Meyer BN, Ferrigni NR, Putnam JE, Jacobsen LB, Nichols DE, McLaughlin JL. Brine shrimp: A convenient general bioassay for active plant constituents. Planta Med 1982;45:31-4.
18. Sandeep, Mittal A. Evaluation of antimicrobial and antioxidant activity of isolated constituents from areal part of cuscuta reflexa Roxb plant. Asian J Pharm Clin Res 2018;3:187-90.
19. Sharma S, Hullatti KK, Kumar S, Brijesh TK. Comparative antioxidant activity of Cuscuta reflexa and Cassytha filiformis. J Pharm Res 2012;5:441-3.
20. Dogruoz N, Zeybek Z, Karagoz A. Antibacterial activity of some plant extracts. IUFS J Biol Res 2008;67:17-21.
21. Yadav NK, Arya RK, Dev K, Sharma C, Hossain Z, Meena S, et al. Alcoholic extract of Eclipta alba shows in vitro antioxidant and anticancer activity without exhibiting toxicological effects. Oxid Med Cell Longev 2017;2017:9094641.
22. Bernfeld P. Amylases alpha and beta. In: Methods in Enzymology. Vol. 1. New York: Academic Press; 1955. p. 149-58.
23. Antia BS, Okokon JE, Okon PA. Hypoglycemic activity of aqueous leaf extract of Persea americana Mill. Indian J Pharmacol 2005;37:325-6.
24. Sharma US, Kumar A. Anti-diabetic effect of Rubus ellipticus fruit extracts in alloxan-induced diabetic rats. J Diabetol 2011;2:1-6.
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How to Cite
Numer Alam, and K. raj Sharma. “ESTIMATION OF PHENOLIC CONTENT, FLAVONOID CONTENT, ANTIOXIDANT, AND ALPHA-AMYLASE INHIBITORY ACTIVITY OF SOME SELECTED PLANTS FROM SIRAHA DISTRICT NEPAL”. Asian Journal of Pharmaceutical and Clinical Research, Vol. 13, no. 4, Feb. 2020, pp. 18-23, doi:10.22159/ajpcr.2020.v13i4.36734.
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