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Jun 8, 2023
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Oct 1, 2024
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Oct 1, 2024
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Abstract

Background: The peel of the fruit Citrus reticulata Blanco has long been used in traditional medicine due to its various properties. Traditional medicine from certain parts of medicinal plants is related to the content of bioactive compounds from the fruit's peel, such as phenolic compounds and flavonoids that can help protect the body from damage caused by free radicals. Objectives: This study aimed to evaluate the total levels of phenolics and flavonoids as well as antioxidants from ethanol, ethyl acetate, and n-hexane extracts from the skin of Citrus reticulata Blanco using DPPH (2,2-diphenyl-1-picrylhydrazil) and ABTS (2,2'-azinobis-(3-ethylbenzothiazolin-6-sulphonate))) methods. Material and Methods: The extraction process was carried out using the maceration ion method with ethanol, ethyl acetate, and n-hexane solvents at room temperature for 24 hours. Total phenolic and flavonoid levels in the extract were determined using UV-Vis spectrophotometry, and antioxidant activity testing was determined based on the extract's ability to neutralize free radicals from DPPH and ABTS. Results: The results showed that the ethanol extract of Citrus reticulata Blanco fruit peel had higher total phenolic and flavonoid levels compared to ethyl acetate and n-hexane extracts. The total phenolic levels in ethanol, ethyl acetate, and n-hexane extracts were 142.02, 74.60, and 57.17 mg GAE/g, respectively. The total flavonoid levels in ethanol, ethyl acetate, and n-hexane extracts were 45.96, 40.22, and 38.54 mg QE/g, respectively. In addition, ethanol extract has also shown the strongest antioxidant activity based on the results of testing with DPPH and ABTS methods. The inhibitory concentration (IC50) of ethanol extract against DPPH and ABTS methods was 23,490 μg/mL and 31,971 μg/mL, respectively, with strong category. Conclusions: This study shows that the skin of Citrus reticulata Blanco fruit contains phenolic compounds and flavonoids that have the potential as natural antioxidants, with ethanol extract being the most promising related to total phenolic and flavonoid levels and antioxidant activity. This information can be used as a basis for developing pharmaceutical dosage products and health supplements that can potentially improve antioxidant/health status in the body.

Keywords

Antioxidant activity Citrus reticulata Blanco fruit peel DPPH and ABTS phenolic and flavonoid total fruit peel

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Fadhlillah, F. M., Miranti, M., Wibowo, D. P., & Purkon, D. B. (2024). Determination of Phenolic and Flavonoid Total Levels and Antioxidant Activity of Ethanol, Ethyl Acetate, and n-Hexane Extracts of Citrus reticulata Blanco Fruit Peel by DPPH and ABTS Methods: Penetapan Kadar Total Fenol dan Flavonoid serta Aktivitas Antioksidan Ekstrak Etanol, Etil Asetat, dan n-Heksan Kulit Buah Citrus reticulata Blanco dengan Metode DPPH dan ABTS. Jurnal Farmasi Galenika (Galenika Journal of Pharmacy) (e-Journal), 10(2), 191-213. https://doi.org/10.22487/j24428744.2024.v10.i2.16399

References

  1. Abramovič, H., Grobin, B., Ulrih, N. P., & Cigić, B. (2017). The methodology applied in DPPH, ABTS and folin-ciocalteau assays has a large influence on the determined antioxidant potential. Acta Chimica Slovenica, 64(2), 491–499. https://doi.org/10.17344/acsi.2017.3408
  2. Agbo, M. O. (2015). Antioxidant, total phenolic and flavonoid content of selected Nigerian medicinal plants. Dhaka University Journal of Pharmaceutical Sciences, 14(1), 35–41. https://doi.org/10.3329/dujps.v14i1.23733
  3. Ahmed, Z. (2017). Seasonal, gender and regional variations in total phenolic, flavonoid, and condensed tannins contents and in antioxidant properties from pistacia atlantica ssp. Leaves. Pharmaceutical Biology, 55(1), 1185–1194. https://doi.org/10.1080/13880209.2017.1291690
  4. Ajiboye, A. A., Dedeke, O. A., & Adeyemo, F. C. (2017). Investigation on antioxidants, free radical scavenger and lipid peroxidation activities of whole grains finger millet (Eleusine coracana L.). International Journal of Plant Biology, 8(1), 40–43. https://doi.org/10.4081/pb.2017.6684
  5. Akbaribazm, M., Khazaei, M. R., & Khazaei, M. (2020). Phytochemicals and antioxidant activity of alcoholic/hydroalcoholic extract of Trifolium pratense. In Chinese Herbal Medicines (Vol. 12, Issue 3, pp. 326–335). Elsevier BV. https://doi.org/10.1016/j.chmed.2020.02.002
  6. Altemimi, A., Lakhssassi, N., Baharlouei, A., Watson, D. G., & Lightfoot, D. A. (2017). Phytochemicals: Extraction, isolation, and identification of bioactive compounds from plant extracts. Plants, 6(4). https://doi.org/10.3390/plants6040042
  7. Alvarez-Arellano, L., Salazar-García, M., & Corona, J. C. (2020). Neuroprotective effects of Quercetin in pediatric neurological diseases. In Molecules (Vol. 25, Issue 23). MDPI AG. https://doi.org/10.3390/molecules25235597
  8. Andriyanto, A., Widi, L. N., Subangkit, M., Tarigan, E., Irarang, Y., Nengsih, R. F., & Manalu, W. (2022). Potential use of Indonesian basil (Ocimum basilicum) maceration to increase estradiol and progesterone synthesis and secretion to improve prenatal growth of offspring using female albino rats as an animal model. Veterinary World, 15(5), 1197–1207. https://doi.org/10.14202/vetworld.2022.1197-1207
  9. Badri, D. V., Chaparro, J. M., Zhang, R., Shen, Q., & Vivanco, J. M. (2013). Application of natural blends of phytochemicals derived from the root exudates of arabidopsis to the soil reveal that phenolic-related compounds predominantly modulate the soil microbiome. Journal of Biological Chemistry, 288(7), 4502–4512. https://doi.org/10.1074/jbc.M112.433300
  10. Baliyan, S., Mukherjee, R., Priyadarshini, A., Vibhuti, A., Gupta, A., Pandey, R. P., & Chang, C. M. (2022). Determination of Antioxidants by DPPH Radical Scavenging Activity and Quantitative Phytochemical Analysis of Ficus religiosa. Molecules, 27(4). https://doi.org/10.3390/molecules27041326
  11. Bhandari, S. (2016). Genotypic variation in carotenoid, ascorbic acid, total phenolic, and flavonoid contents, and antioxidant activity in selected tomato breeding lines. Horticulture Environment and Biotechnology, 57(5), 440–452. https://doi.org/10.1007/s13580-016-0144-3
  12. Cerón-Carrasco, J. P. (2014). Theoretical insights on the antioxidant activity of edaravone free radical scavengers derivatives. Chemical Physics Letters, 599, 73–79. https://doi.org/10.1016/j.cplett.2014.03.010
  13. Chen, Y., Wang, E., Wei, Z., Zheng, Y., Yan, R., & Ma, X. (2019). Phytochemical analysis, cellular antioxidant, α-glucosidase inhibitory activities of various herb plant organs. Industrial Crops and Products, 141(September), 111771. https://doi.org/10.1016/j.indcrop.2019.111771
  14. Daulay, A. S., Taufik, M., Ridwanto, R., Syahputra, R. A., & Astriliana, A. (2019, October 18). Effect of Particle Size on Fresh Turmeric (Curcuma Longa L.) and Simplicia Toward Content of Curcumin Compound. The Proceedings of The 5th Annual International Seminar on Trends in Science and Science Education (AISTSSE). https://doi.org/10.4108/eai.18-10-2018.2287374
  15. de Moura, C., Kabbas Junior, T., Pedreira, F. R. de O., Azevedo, L., Furtado, M. M., Sant’Ana, A. S., Franchin, M., Gonzaga, V. R., Cui, Y., Wen, M., Zhang, L., Pereira, R. P., & Granato, D. (2022). Purple tea (Camellia sinensis var. assamica) leaves as a potential functional ingredient: From extraction of phenolic compounds to cell-based antioxidant/biological activities. Food and Chemical Toxicology, 159, 112668. https://doi.org/10.1016/J.FCT.2021.112668
  16. Depkes RI. (2000). Parameter Standar Umum Ekstrak Tumbuhan Obat. Departemen Kesehatan RI.
  17. Erkekoglou, I. (2017). Functional Teas from the Leaves of Arbutus unedo: Phenolic Content, Antioxidant Activity, and Detection of Efficient Radical Scavengers. Plant Foods for Human Nutrition, 72(2), 176–183. https://doi.org/10.1007/s11130-017-0607-4
  18. Farasat, M. (2014). Antioxidant activity, total phenolics and flavonoid contents of some edible green seaweeds from northern coasts of the Persian gulf. Iranian Journal of Pharmaceutical Research, 13(1), 163–170. https://api.elsevier.com/content/abstract/scopus_id/84903635579
  19. Fidrianny, I. (2013a). Antioxidant activities from various bulbs extracts of three kinds allium using DPPH, ABTS assays and correlation with total phenolic, flavonoid, carotenoid content. International Journal of Research in Pharmaceutical Sciences, 4(3), 438–444. https://api.elsevier.com/content/abstract/scopus_id/84897514839
  20. Fidrianny, I. (2013b). Antioxidant capacities of various leaves extract from five colors varieties of sweet potatoes tubers using ABTS, DPPH assays and correlation with total flavonoid, phenolic, carotenoid content. Research Journal of Medicinal Plant, 7(3), 130–140. https://doi.org/10.3923/rjmp.2013.130.140
  21. Fidrianny, I. (2015). Antioxidant activities of different polarity extracts from three organs of makrut lime (Citrus hystrix DC) and correlation with total flavonoid, phenolic, carotenoid content. Asian Journal of Pharmaceutical and Clinical Research, 8(4), 239–243. https://api.elsevier.com/content/abstract/scopus_id/84937932557
  22. Fikranus Shofa, A., Alam, T., & Nuralih, N. (2022). Uji Aktivitas Sitotoksik Ekstrak Polar, Semipolar, dan Non-Polar Daun Sambiloto (Andrographis paniculata) terhadap Sel Kanker Hati (HepG2) Cytotoxic Activity Study of Polar, Semipolar, and Non-Polar Extracts of Sambiloto Leaves (Andrographis paniculata) Against Hepatocellular Carcinoma (HepG2) Cell Line. Jurnal Kefarmasian Indonesia, 12(1), 25–30. https://doi.org./10.2
  23. Fowler, A. A., Truwit, J. D., Hite, R. D., Morris, P. E., Dewilde, C., Priday, A., Fisher, B., Thacker, L. R., Natarajan, R., Brophy, D. F., Sculthorpe, R., Nanchal, R., Syed, A., Sturgill, J., Martin, G. S., Sevransky, J., Kashiouris, M., Hamman, S., Egan, K. F., … Halquist, M. (2019). Effect of Vitamin C Infusion on Organ Failure and Biomarkers of Inflammation and Vascular Injury in Patients with Sepsis and Severe Acute Respiratory Failure: The CITRIS-ALI Randomized Clinical Trial. JAMA - Journal of the American Medical Association, 322(13), 1261–1270. https://doi.org/10.1001/jama.2019.11825
  24. Ge, L., Li, S. P., & Lisak, G. (2020a). Advanced sensing technologies of phenolic compounds for pharmaceutical and biomedical analysis. Journal of Pharmaceutical and Biomedical Analysis, 179. https://doi.org/10.1016/J.JPBA.2019.112913
  25. Ge, L., Li, S. P., & Lisak, G. (2020b). Advanced sensing technologies of phenolic compounds for pharmaceutical and biomedical analysis. In Journal of Pharmaceutical and Biomedical Analysis (Vol. 179). Elsevier B.V. https://doi.org/10.1016/j.jpba.2019.112913
  26. Gómez-Mejía, E., Rosales-Conrado, N., León-González, M. E., & Madrid, Y. (2019). Citrus peels waste as a source of value-added compounds: Extraction and quantification of bioactive polyphenols. Food Chemistry, 295, 289–299. https://doi.org/10.1016/j.foodchem.2019.05.136
  27. Granato, D., Shahidi, F., Wrolstad, R., Kilmartin, P., Melton, L. D., Hidalgo, F. J., Miyashita, K., Camp, J. van, Alasalvar, C., Ismail, A. B., Elmore, S., Birch, G. G., Charalampopoulos, D., Astley, S. B., Pegg, R., Zhou, P., & Finglas, P. (2018). Antioxidant activity, total phenolics and flavonoids contents: Should we ban in vitro screening methods? Food Chemistry, 264(April), 471–475. https://doi.org/10.1016/j.foodchem.2018.04.012
  28. Gurning, K., & Sinaga, D. H. (2020). Characterization and Screening of Phytochemical Secondary Metabolite of Seri (Muntingia calabura, L) Leaves which is Potential as an Anti-Diabetic based on Indonesian Herbal Medicine Standard. Journal of Drug Delivery and Therapeutics, 10(6-s), 92–94. https://doi.org/10.22270/jddt.v10i6-s.4458
  29. Handayani, S., Wirasutisna, K. R., & Insanu, M. (2017). Penapisan Fitokimia dan Karakterisasi Simplisia Daun Jambu Mawar (Syzygium jambos Alston). Jf Fik Uinam, 5(3), 174–179.
  30. Hanin, N. N. F., & Pratiwi, R. (2017). Kandungan Fenolik, Flavonoid dan Aktivitas Antioksidan Ekstrak Daun Paku Laut (Acrostichum aureum L.) Fertil dan Steril di Kawasan Mangrove Kulon Progo, Yogyakarta. Journal of Tropical Biodiversity and Biotechnology, 2(2), 51. https://doi.org/10.22146/jtbb.29819
  31. Hasnaeni, H., & Aminah, A. (2019). Uji Aktivitas Antioksidan dan Profil Fitokimia Ekstrak Kayu Beta-beta (Lunasia amara Blanco.). Jurnal Farmasi Galenika (Galenika Journal of Pharmacy) (e-Journal), 5(1), 101–107. https://doi.org/10.22487/j24428744.2019.v5.i1.12404
  32. Husni, E., Ismed, F., & Afriyandi, D. (2020). Standardization study of simplicia and extract of calamondin (citrus microcarpa bunge) peel, quantification of hesperidin and antibacterial assay. Pharmacognosy Journal, 12(4), 777–783. https://doi.org/10.5530/pj.2020.12.111
  33. Ikawati, M., Armandari, I., Khumaira, A., & Ertanto, Y. (2019). Effects of Peel Extract from Citrus reticulata and Hesperidin, a Citrus Flavonoid, on Macrophage Cell Line. Indonesian Journal of Pharmacy, 30(4), 260–268. https://doi.org/10.14499/indonesianjpharm30iss4pp260
  34. Isnawati, A. P., & Retnaningsih, A. (2018). Perbandingan Teknik Ekstraksi Maserasi Dengan Infusa pada Pengujian Aktivitas Daya Hambat Daun Sirih Hijau (Piper betle L.) Terhadap Escherichia coli. Jurnal Farmasi Malahayati, 1(1), 19–24.
  35. Jadid, N., Dewi, ;, Sylviana, H. ;, Hartanti, R., Byan, ;, Arraniry, A., Rizka, ;, Rachman, Y., Wikanta, W., Hidayati, D., Hartanti, S. R., Arraniry, B. A., & Rachman, R. Y. (2017). Antioxidant activities of different solvent extracts of Piper retrofractum Vahl. using DPPH assay  Articles You May Be Interested In Investigating physical and visual alterations of oven-dried cabya (Piper retrofractum Vahl.) Antioxidant Activities of Different Solvent Extracts of Piper retrofractum Vahl. using DPPH Assay. AIP, 1854, 20019. https://doi.org/10.1063/1.4985410
  36. Jang, S. J., Park, H. H., & Kuk, Y. I. (2021). Application of various extracts enhances the growth and yield of cucumber (Cucumis sativus l.) without compromising the biochemical content. Agronomy, 11(3). https://doi.org/10.3390/agronomy11030505
  37. Jebitta, S. R. (2016). Antioxidant activity, total phenol, flavonoid, and anthocyanin contents of Jamun (Syzygium Cumini) pulp powder. Asian Journal of Pharmaceutical and Clinical Research, 9(2), 361–363. https://api.elsevier.com/content/abstract/scopus_id/84960088171
  38. Kalaskar, A. R., Bhowate, R. R., Kalaskar, R. R., & Ghonmode, S. (2021). Novel neem leaves extract mouthwash therapy for oral lichen planus. Journal of Herbal Medicine, 26, 100408. https://doi.org/10.1016/j.hermed.2020.100408
  39. Kanlayavattanakul, M., Pawakongbun, T., & Lourith, N. (2019). Dendrobium orchid polysaccharide extract: Preparation, characterization and in vivo skin hydrating efficacy. Chinese Herbal Medicines, 11(4), 400–405. https://doi.org/10.1016/j.chmed.2019.03.012
  40. Kemenkes, R. I. (2014). Farmakope Indonesia Edisi V. Jakarta: Direktorat Jendral Bina Kefarmasian Dan Alat Kesehatan Republik Indonesia, 195.
  41. Koomson, D. A. (2018). Phytochemical constituents, total saponins, alkaloids, flavonoids and vitamin c contents of ethanol extracts of five solanum torvum fruits. Pharmacognosy Journal, 10(5), 946–950. https://doi.org/10.5530/pj.2018.5.160
  42. Kustiawan, P. M., Arbainsyah, A., & Setiawan, I. M. (2021). Antioxidant and Antibacterial Activity of Yellow Wood (Coscinium fenestratum) Fruits Peel from East Kalimantan. Jurnal Farmasi Galenika (Galenika Journal of Pharmacy) (e-Journal), 7(2), 191–200. https://doi.org/10.22487/j24428744.2021.v7.i2.15640
  43. Mahindrakar, K. (2020). Ultrasonic assisted aqueous extraction of catechin and gallic acid from Syzygium cumini seed kernel and evaluation of total phenolic, flavonoid contents and antioxidant activity. Chemical Engineering and Processing - Process Intensification, 149. https://doi.org/10.1016/j.cep.2020.107841
  44. Masisi, K., Masamba, R., Lashani, K., Li, C., Kwape, T. E., & Gaobotse, G. (2021). Antioxidant, Cytotoxicity and Cytoprotective Potential of Extracts of Grewia flava and Grewia bicolor Berries. Journal of Pharmacopuncture, 24(1), 24–31. https://doi.org/10.3831/KPI.2021.24.1.24
  45. Mohammadi, M. (2016). Phytochemical screening, total phenolic and flavonoid contents and antioxidant activity of Anabasis setifera and Salsola tomentosa extracted with different extraction methods and solvents. Oriental Pharmacy and Experimental Medicine, 16(1), 31–35. https://doi.org/10.1007/s13596-016-0220-3
  46. Nur, S., Sami, F. J., Awaluddin, A., & Afsari, M. I. A. (2019). Korelasi Antara Kadar Total Flavonoid dan Fenolik dari Ekstrak dan Fraksi Daun Jati Putih (Gmelina Arborea Roxb.) Terhadap Aktivitas Antioksidan. Jurnal Farmasi Galenika (Galenika Journal of Pharmacy) (e-Journal), 5(1), 33–42. https://doi.org/10.22487/j24428744.2019.v5.i1.12034
  47. Oktavia, F. D., & Sutoyo, S. (2021). SKRINING FITOKIMIA, KANDUNGAN FLAVONOID TOTAL, DAN AKTIVITAS ANTIOKSIDAN EKSTRAK ETANOL TUMBUHAN Selaginella doederleinii. Jurnal Kimia Riset, 6(2), 141–153.
  48. Pandey, G. (2018). Altitudinal variation of berberine, total phenolics and flavonoid content in Thalictrum foliolosum and their correlation with antimicrobial and antioxidant activities. Journal of Ayurveda and Integrative Medicine, 9(3), 169–176. https://doi.org/10.1016/j.jaim.2017.02.010
  49. Pasupuleti, V. R., Arigela, C. S., Gan, S. H., Salam, S. K. N., Krishnan, K. T., Rahman, N. A., & Jeffree, M. S. (2020). A review on oxidative stress, diabetic complications, and the roles of honey polyphenols. In Oxidative Medicine and Cellular Longevity (Vol. 2020). Hindawi Limited. https://doi.org/10.1155/2020/8878172
  50. Purkon, D. B., Fadhlillah, F. M., Maigoda, T. C., Iwo, M. I., Soemardji, A. A., Nadhifah, A., & Sudaryat, Y. (2022). Phytochemical, Use in Ethnomedicine, and Therapeutic Activities of Marchantia Genus. Journal of Vocational Health Studies, 5(3), 174–185. https://doi.org/10.20473/jvhs.v5.i3.2022.174-185
  51. Purkon, D. B., Iwo, M. I., Soemardji, A. A., Rahmawati, S. F., Fadhlillah, F. M., & Nadhifah, A. (2021). Immunostimulant Activity of Marchantia paleacea Bertol. Herb Liverwort Ethanol Extract in BALB/c Mice. Indonesian Journal of Pharmacy, 32(4), 464–473. https://doi.org/10.22146/ijp.2128
  52. Purkon, D. B., Kusmiyati, M., Trinovani, E., Fadhlillah, F. M., Widyastiwi, W., Roseno, M. H., Khristian, E., & Nadhifah, A. (2022). The hepatoprotective effect of Marchantia paleacea bertol. extract against acetaminophen-induced liver damage in rat: biochemical and histological evidence. Journal of Research in Pharmacy, 26(6), 1857–1867. https://doi.org/10.29228/jrp.275
  53. Rababah, T. M. (2015). Effects of drying process on total phenolics, antioxidant activity and flavonoid contents of common mediterranean herbs. International Journal of Agricultural and Biological Engineering, 8(2), 145–150. https://doi.org/10.3965/j.ijabe.20150802.1496
  54. Rafi, M. (2018). Total phenolics, flavonoids, and anthocyanin contents of six Vireya Rhododendron from Indonesia and evaluation of their antioxidant activities. Journal of Applied Pharmaceutical Science, 8(9), 49–54. https://doi.org/10.7324/JAPS.2018.8908
  55. Rahmanisa, S., & Oktaria, R. (2016). Pengaruh Epigallocatechin-3-Gallate ( EGCG ) pada Teh Hijau Terhadap Acne vulgaris The Effect of Epigallocatechin-3-Gallate ( EGCG ) in Green Tea to Acne vulgaris. 5(April), 101–105.
  56. Roshanak, S. (2016). Evaluation of seven different drying treatments in respect to total flavonoid, phenolic, vitamin C content, chlorophyll, antioxidant activity and color of green tea (Camellia sinensis or C. assamica) leaves. Journal of Food Science and Technology, 53(1), 721–729. https://doi.org/10.1007/s13197-015-2030-x
  57. Sembiring, E. (2018). Phytochemical screening, total flavonoid and total phenolic content and antioxidant activity of different parts of Caesalpinia bonduc (L.) Roxb. Pharmacognosy Journal, 10(1), 123–127. https://doi.org/10.5530/pj.2018.1.22
  58. Sério, S. (2014). Analysis of commercial grape raisins: Phenolic content, antioxidant capacity and radical scavenger activity. Ciencia e Tecnica Vitivinicola, 29(1), 1–8. https://doi.org/10.1051/ctv/20142901001
  59. Sinaga, B., Sondak, E. S., & Ningsih, A. W. (2021). Effect of Drying Method On The Quality of Simplicia Leaves of Red Guava (Psidium guajava L.) (Vol. 1, Issue 2).
  60. Sridhar, K., & Charles, A. L. (2019). In vitro antioxidant activity of Kyoho grape extracts in DPPH [rad] and ABTS [rad] assays: Estimation methods for EC 50 using advanced statistical programs. Food Chemistry, 275, 41–49. https://doi.org/10.1016/j.foodchem.2018.09.040
  61. Sulastri, E. (2018). Total phenolic, total flavonoid, quercetin content and antioxidant activity of standardized extract of moringa oleifera leaf from regions with different elevation. Pharmacognosy Journal, 10(6). https://doi.org/10.5530/pj.2018.6s.20
  62. Sulastri, E., & Ikram, M. (2017). UJI STABILITAS DAN AKTIVITAS ANTIOKSIDAN MIKROEMULSI LIKOPEN TOMAT(Solanum lycopersicum L.) STABILITY TEST AND ANTIOXIDANT ACTIVITY OF TOMATO LYCOPENE(Solanum lycopersicum L.) MICROEMULSION. GALENIKA Journal of Pharmacy, 3(1), 10–17.
  63. Sultana, M. (2012). Quantitative analysis of total phenolic, flavonoids and tannin contents in acetone and n-hexane extracts of Ageratum conyzoides. International Journal of ChemTech Research, 4(3), 996–999. https://api.elsevier.com/content/abstract/scopus_id/84876071052
  64. Tristantini, D., Wahidin, W., Feliana, F., Widigarka, M., & Santoso, L. L. (2021). Immunomodulatory and antioxidant activity from Indonesian anti-degenerative herbs water extract. Journal of Complementary and Integrative Medicine, 18(4), 695–700. https://doi.org/10.1515/jcim-2020-0223
  65. Tungmunnithum, D., Thongboonyou, A., Pholboon, A., & Yangsabai, A. (2018). Flavonoids and Other Phenolic Compounds from Medicinal Plants for Pharmaceutical and Medical Aspects: An Overview. Medicines, 5(3), 93. https://doi.org/10.3390/medicines5030093
  66. Vongsak, B. (2013). Maximizing total phenolics, total flavonoids contents and antioxidant activity of Moringa oleifera leaf extract by the appropriate extraction method. Industrial Crops and Products, 44, 566–571. https://doi.org/10.1016/j.indcrop.2012.09.021
  67. WHO. (1998). Quality control methods for medicinal plant materials. World Health Organization (WHO).
  68. WHO. (2011). Quality Control Methods for Herbal Materials. World Health Organization (WHO).
  69. Wu, Y., He, Y., Wang, R., & Zhao, X. (2021). Preventive effect of flavonoid extract from the Peel of Gonggan (Citrus reticulata blanco Var. Gonggan) on CCl4-induced acute liver injury in mice. Journal of Inflammation Research, 14, 5111–5121. https://doi.org/10.2147/JIR.S332134
  70. Zengin, G. (2016). Total phenolics, flavonoids, condensed tannins content of eight centaurea species and their broad inhibitory activities against cholinesterase, tyrosinase, α-amylase and α-glucosidase. Notulae Botanicae Horti Agrobotanici Cluj-Napoca, 44(1), 195–200. https://doi.org/10.15835/nbha44110259
  71. Zhang, W., Liu, D., Fu, X., Xiong, C., & Nie, Q. (2022). Peel Essential Oil Composition and Antibacterial Activities of Citrus x sinensis L. Osbeck ‘Tarocco’ and Citrus reticulata Blanco. Horticulturae, 8(9), 793. https://doi.org/10.3390/HORTICULTURAE8090793/S1
  72. Zhang, Y. J. (2015). Antioxidant phytochemicals for the prevention and treatment of chronic diseases. In Molecules (Vol. 20, Issue 12, pp. 21138–21156). https://doi.org/10.3390/molecules201219753
  73. Zohra, T. (2019). Extraction optimization, total phenolic, flavonoid contents, HPLC-DAD analysis and diverse pharmacological evaluations of Dysphania ambrosioides (L.) Mosyakin & Clemants. Natural Product Research, 33(1), 136–142. https://doi.org/10.1080/14786419.2018.1437428