Phycoremediation of Dyes: A Mini-Review on Mechanisms and Affecting Factors

Abdel Ghafar, H. H., Embaby, M. A., Radwan, E. K., & Abdel-Aty, A. M. (2017). Biosorptive removal of basic dye methylene blue using raw and CaCl2 treated biomass of green microalga Scenedesmus obliquus. Desalination and Water Treatment, 81, 274–281.
Agoun, N. A., & Avci, F. G. (2025). Phycoremediation: A path towards heavy metal bioremediation from wastewater. Journal of Chemical Technology & Biotechnology, 100(1), 13–23.
Ahammed, Md. S., Baten, Md. A., Ali, M. A., Mahmud, S., Islam, Md. S., Thapa, B. S., Islam, Md. A., Miah, Md. A., & Tusher, T. R. (2023). Comparative Evaluation of Chlorella vulgaris and Anabaena variabilis for Phycoremediation of Polluted River Water: Spotlighting Heavy Metals Detoxification. Biology, 12(5), 675.
Ahmed, T., Shahid, M., Azeem, F., Rasul, I., Shah, A. A., Noman, M., Hameed, A., Manzoor, N., Manzoor, I., & Muhammad, S. (2018). Biodegradation of plastics: Current scenario and future prospects for environmental safety. Environmental Science and Pollution Research, 25(8), 7287–7298.
Aksu, Z., & Tezer, S. (2005). Biosorption of reactive dyes on the green alga Chlorella vulgaris. Process Biochemistry, 40(3), 1347–1361. 
Ali, H. (2010). Biodegradation of Synthetic Dyes—A Review. Water, Air, & Soil Pollution, 213(1–4), 251–273. 
Al-Jabri, H., Das, P., Khan, S., Thaher, M., & AbdulQuadir, M. (2020). Treatment of Wastewaters by Microalgae and the Potential Applications of the Produced Biomass—A Review. Water, 13(1), 27.
Al-Tohamy, R., Ali, S. S., Li, F., Okasha, K. M., Mahmoud, Y. A.-G., Elsamahy, T., Jiao, H., Fu, Y., & Sun, J. (2022). A critical review on the treatment of dye-containing wastewater: Ecotoxicological and health concerns of textile dyes and possible remediation approaches for environmental safety. Ecotoxicology and Environmental Safety, 231, 113160.
Anbia, M., & Ghaffari, A. (2011). Removal of malachite green from dye wastewater using mesoporous carbon adsorbent. Journal of the Iranian Chemical Society, 8(1), S67–S76.
Anto, S., Sudhakar, M. P., Shan Ahamed, T., Samuel, M. S., Mathimani, T., Brindhadevi, K., & Pugazhendhi, A. (2021). Activation strategies for biochar to use as an efficient catalyst in various applications. Fuel, 285, 119205. 
Aravindhan, R., Rao, J. R., & Nair, B. U. (2007). Kinetic and equilibrium studies on biosorption of basic blue dye by green macro algae Caulerpa scalpelliformis. Journal of Environmental Science and Health, Part A, 42(5), 621–631.
Arteaga, L. C., Zavaleta, M. P., Eustaquio, W. M., & Bobadilla, J. M. (2018). Removal of aniline blue dye using live microalgae Chlorella vulgaris. Journal of Energy & Environmental Sciences, 2(1), Article 1.
Ayele, A., Getachew, D., Kamaraj, M., & Suresh, A. (2021). Phycoremediation of Synthetic Dyes: An Effective and Eco-Friendly Algal Technology for the Dye Abatement. Journal of Chemistry, 2021, 1–14.
Babuji, P., Thirumalaisamy, S., Duraisamy, K., & Periyasamy, G. (2023). Human Health Risks due to Exposure to Water Pollution: A Review. Water, 15(14), Article 14.
Bayramoğlu, G., & Yakup Arıca, M. (2007). Biosorption of benzidine based textile dyes “Direct Blue 1 and Direct Red 128” using native and heat-treated biomass of Trametes versicolor. Journal of Hazardous Materials, 143(1–2), 135–143.
Biris-Dorhoi, E.-S., Michiu, D., Pop, C. R., Rotar, A. M., Tofana, M., Pop, O. L., Socaci, S. A., & Farcas, A. C. (2020). Macroalgae—A Sustainable Source of Chemical Compounds with Biological Activities. Nutrients, 12(10), 3085.
Bonyadi, Z., Nasoudari, E., Ameri, M., Ghavami, V., Shams, M., & Sillanpää, M. (2022). Biosorption of malachite green dye over Spirulina platensis mass: Process modeling, factors optimization, kinetic, and isotherm studies. Applied Water Science, 12(7), 167.
Brahmbhatt, N., & Jasrai, R. (2013). Biodegradation of Reactive Dyes by Two Microalgal Species. 4, 4–438.
Cengiz Sahin, S., & Aksu, S. (2017). Adsorption of Dyes from Aqueous Textile By-Products on Activated Carbon from Scenedesmus obliquus. Analytical Letters, 50(11), 1812–1830.
Chen, C., Fan, D., Ling, H., Huang, X., Yang, G., Cai, D., Zhao, J., & Bi, Y. (2022). Microwave catalytic co-pyrolysis of Chlorella vulgaris and high density polyethylene over activated carbon supported monometallic: Characteristics and bio-oil analysis. Bioresource Technology, 363, 127881.
Chia, W. Y., Ying Tang, D. Y., Khoo, K. S., Kay Lup, A. N., & Chew, K. W. (2020). Nature’s fight against plastic pollution: Algae for plastic biodegradation and bioplastics production. Environmental Science and Ecotechnology, 4, 100065.
Chin, J. Y., Chng, L. M., Leong, S. S., Yeap, S. P., Yasin, N. H. M., & Toh, P. Y. (2020). Removal of Synthetic Dye by Chlorella vulgaris Microalgae as Natural Adsorbent. Arabian Journal for Science and Engineering, 45(9), 7385–7395.
Chinaglia, S., Tosin, M., & Degli-Innocenti, F. (2018). Biodegradation rate of biodegradable plastics at molecular level. Polymer Degradation and Stability, 147, 237–244.
Daneshvar, N., Ayazloo, M., Khataee, A. R., & Pourhassan, M. (2005). Biodegradation of the textile dye malachite green by Microalgae Cosmarium sp. International Journal for Science and High Technology and Environmental Sciences, 1384, 1–5.
Daud, N. M., Abdullah, S. R. S., Hasan, H. A., Ismail, N. ’Izzati, & Dhokhikah, Y. (2022). Integrated physical-biological treatment system for batik industry wastewater: A review on process selection. Science of The Total Environment, 819, 152931.
Doğan, M., Alkan, M., Demirbaş, Ö., Özdemir, Y., & Özmetin, C. (2006a). Adsorption kinetics of maxilon blue GRL onto sepiolite from aqueous solutions. Chemical Engineering Journal, 124(1–3), 89–101.
Doğan, M., Alkan, M., Demirbaş, Ö., Özdemir, Y., & Özmetin, C. (2006b). Adsorption Kinetics of Maxilon Blue GRL onto Sepiolite from Aqueous Solutions. Chemical Engineering Journal, 124, 89–101.
El Boukhari, M. E. M., Barakate, M., Bouhia, Y., & Lyamlouli, K. (2020). Trends in Seaweed Extract Based Biostimulants: Manufacturing Process and Beneficial Effect on Soil-Plant Systems. Plants, 9(3), 359.
El-Sheekh, M., Abou-El-Souod, G., & El Asrag, H. (2018). Biodegradation of some dyes by the green Alga Chlorella vulgaris and the Cyanobacterium Aphanocapsa elachista. Egyptian Journal of Botany, 0(0), 0–0.
Ergene, A., Ada, K., Tan, S., & Katırcıoğlu, H. (2009). Removal of Remazol Brilliant Blue R dye from aqueous solutions by adsorption onto immobilized Scenedesmus quadricauda: Equilibrium and kinetic modeling studies. Desalination, 249(3), 1308–1314.
Esmaeili Nasrabadi, A., Eydi, M., & Bonyadi, Z. (2023). Utilizing Chlorella vulgaris algae as an eco-friendly coagulant for efficient removal of polyethylene microplastics from aquatic environments. Heliyon, 9(11), e22338.
Feng, H., Sun, C., Zhang, C., Chang, H., Zhong, N., Wu, W., Wu, H., Tan, X., Zhang, M., & Ho, S.-H. (2022). Bioconversion of mature landfill leachate into biohydrogen and volatile fatty acids via microalgal photosynthesis together with dark fermentation. Energy Conversion and Management, 252, 115035.
Fomina, M., & Gadd, G. M. (2014). Biosorption: Current perspectives on concept, definition and application. Bioresource Technology, 160, 3–14.
Foroughi-Dahr, M., Abolghasemi, H., Esmaili, M., Shojamoradi, A., & Fatoorehchi, H. (2015). Adsorption Characteristics of Congo Red from Aqueous Solution onto Tea Waste. Chemical Engineering Communications, 202(2), 181–193.
Gani, P., Sunar, N. M., Matias-Peralta, H., Jamaian, S. S., & Latiff, A. A. A. (2016). Effects of different culture conditions on the phycoremediation efficiency of domestic wastewater. Journal of Environmental Chemical Engineering, 4(4), 4744–4753.
Gokulan, R., Avinash, A., Prabhu, G. G., & Jegan, J. (2019). Remediation of remazol dyes by biochar derived from Caulerpa scalpelliformis—An eco-friendly approach. Journal of Environmental Chemical Engineering, 7(5), 103297.
Hamouda, R. A., El‑Naggar, N. E.-A., & Abou-El-Souod, G. W. (2022). Simultaneous bioremediation of Disperse orange-2RL Azo dye and fatty acids production by Scenedesmus obliquus cultured under mixotrophic and heterotrophic conditions. Scientific Reports, 12(1), 20768.
Han, M., Liu, Z., Huang, S., Zhang, H., Yang, H., Liu, Y., Zhang, K., & Zeng, Y. (2024). Application of Biochar-Based Materials for Effective Pollutant Removal in Wastewater Treatment. Nanomaterials, 14(23), Article 23.
Hannachi, Y., & Hafidh, A. (2020). Biosorption potential of Sargassum muticum algal biomass for methylene blue and lead removal from aqueous medium. International Journal of Environmental Science and Technology, 17(9), 3875–3890. 
Hazaimeh, M. (2023). Phycoremediation of heavy metals and production of biofuel from generated algal biomass: A review. Environmental Science and Pollution Research, 30(51), 109955–109972. 
Hernández-Zamora, M., Cristiani-Urbina, E., Martínez-Jerónimo, F., Perales-Vela, H. V., Ponce-Noyola, T., Montes-Horcasitas, M. del C., & Cañizares-Villanueva, R. O. (2015). Bioremoval of the azo dye Congo Red by the microalga Chlorella vulgaris. Environmental Science and Pollution Research, 22(14), 10811–10823.
Hoong, H. N. J., & Ismail, N. (2018). Removal of Dye in Wastewater by Adsorption-Coagulation Combined System with Hibiscus sabdariffa as the Coagulant. MATEC Web of Conferences, 152, 01008.
Huang, X., Zhang, C., Zhu, S., Chen, D., & Ho, S.-H. (2020). Effects of Biochar on Microalgal Growth: Difference between Dissolved and Undissolved Fractions. ACS Sustainable Chemistry & Engineering, 8(24), 9156–9164.
Khalaf, H. A., El-Sheekh, M. M., & Makhlof, M. E. M. (2023). Lychaete pellucida as a novel biosorbent for the biodegradation of hazardous azo dyes. Environmental Monitoring and Assessment, 195(8), 929. 
Khalaf, M. A. (2008). Biosorption of reactive dye from textile wastewater by non-viable biomass of Aspergillus niger and Spirogyra sp. Bioresource Technology, 99(14), 6631–6634.
Khataee, A. R., Vafaei, F., & Jannatkhah, M. (2013). Biosorption of three textile dyes from contaminated water by filamentous green algal Spirogyra sp.: Kinetic, isotherm and thermodynamic studies. International Biodeterioration & Biodegradation, 83, 33–40.
Kholssi, R., Marks, E. A. N., Montero, O., Maté, A. P., Debdoubi, A., & Rad, C. (2018). The growth of filamentous microalgae is increased on biochar solid supports. Biocatalysis and Agricultural Biotechnology, 13, 182–185. 
Kumar, R., Kalaiselvan, V., Verma, R., Kaur, I., Kumar, P., & Singh, G. (2017). Veterinary pharmacovigilance in India: A need of hour. Indian Journal of Pharmacology, 49(1), 2.
Kumar, R., Kundu, D., Kormoker, T., Joshi, S., Rose, P. K., Kumar, S., Sahoo, P. K., Sharma, P., & Lamba, J. (2024). Phycoremediation of potentially toxic elements for agricultural and industrial wastewater treatment: Recent advances, challenges, and future prospects. Desalination and Water Treatment, 319, 100505.
Majumdar, R., Shaikh, W. A., Chakraborty, S., & Chowdhury, S. (2022). Chapter 12—A review on microbial potential of toxic azo dyes bioremediation in aquatic system. In S. Das & H. R. Dash (Eds.), Microbial Biodegradation and Bioremediation (Second Edition) (pp. 241–261). Elsevier.
Majumder, S., Gupta, S., & Raghuvanshi, S. (2014). CHAPTER 3. Removal of Dissolved Metals by Bioremediation. In S. Sharma (Ed.), Heavy Metals In Water (pp. 44–56). Royal Society of Chemistry.
Maleki, A., Mahvi, A. H., Ebrahimi, R., & Zandsalimi, Y. (2010). Study of photochemical and sonochemical processes efficiency for degradation of dyes in aqueous solution. Korean Journal of Chemical Engineering, 27(6), 1805–1810.
Marungrueng, K., & Pavasant, P. (2006). Removal of basic dye (Astrazon Blue FGRL) using macroalga Caulerpa lentillifera. Journal of Environmental Management, 78(3), 268–274.
Marungrueng, K., & Pavasant, P. (2007). High performance biosorbent (Caulerpa lentillifera) for basic dye removal. Bioresource Technology, 98(8), 1567–1572.
Mcyotto, F., Wei, Q., Macharia, D. K., Huang, M., Shen, C., & Chow, C. W. K. (2021). Effect of dye structure on color removal efficiency by coagulation. Chemical Engineering Journal, 405, 126674.
Mohamed, S. M. I., Güner, E. K., Yılmaz, M., & El Nemr, A. (2023). Removal of Cr6+ ions and mordant violet 40 dye from liquid media using Pterocladia capillacea red algae derived activated carbon-iron oxides. Scientific Reports, 13(1), 18306. 
Namasivayam, C., Kavitha, D., & Jenisha, J. (2024). Kavitha paper 1.
Narayanan, M., Prabhakaran, M., Natarajan, D., Kandasamy, S., Raja, R., Carvalho, I. S., Ashokkumar, V., Chinnathambi, A., Alharbi, S. A., Devarayan, K., & Pugazhendhi, A. (2021). Phycoremediation potential of Chlorella sp. On the polluted Thirumanimutharu river water. Chemosphere, 277, 130246.
Nguyen, H. T., Yoon, Y., Ngo, H. H., & Jang, A. (2021). The application of microalgae in removing organic micropollutants in wastewater. Critical Reviews in Environmental Science and Technology, 51(12), 1187–1220. 
Nyika, J., & Dinka, M. O. (2023). Factors and mechanisms regulating heavy metal phycoremediation in polluted water. Discover Water, 3(1), 14.
Oberholster, P. J., Schoeman, Y., & Botha, A.-M. (2024). Is Africa Ready to Use Phycoremediation to Treat Domestic Wastewater as an Alternative Natural Base Solution? A Case Study. Phycology, 4(1), Article 1.
Omar, H. (2008). Algal Decolorization and Degradation of Monoazo and Diazo Dyes. Pakistan Journal of Biological Sciences: PJBS, 11, 1310–1316.
Parida, S., Mandal, A. K., Behera, A. K., Patra, S., Nayak, R., Behera, C., & Jena, M. (2025). A comprehensive review on phycoremediation of azo dye to combat industrial wastewater pollution. Journal of Water Process Engineering, 70, 107088.
Pholnak, P., Sittiyothee, S., Sirisathitkul, C., & Sirisathitkul, Y. (2022). Dye removal efficiency of fresh and dry alginate beads incorporating zinc oxide. Arab Journal of Basic and Applied Sciences, 29(1), 53–64.
Pooja, N., Chakraborty, I., Rahman, Md. H., & Mazumder, N. (2023). An insight on sources and biodegradation of bioplastics: A review. 3 Biotech, 13(7), 220.
Prasad, R. (Ed.). (2021). Phytoremediation for Environmental Sustainability. Springer Nature Singapore.
Pratiwi, D., Prasetyo, D. J., & Poeloengasih, C. D. (2019). Adsorption of Methylene Blue dye using Marine algae Ulva lactuca. IOP Conference Series: Earth and Environmental Science, 251, 012012.
Radziff, S. B. M., Ahmad, S. A., Shaharuddin, N. A., Merican, F., Kok, Y.-Y., Zulkharnain, A., Gomez-Fuentes, C., & Wong, C.-Y. (2021). Potential Application of Algae in Biodegradation of Phenol: A Review and Bibliometric Study. Plants, 10(12), 2677.
Saloglu, D., & Sahin, O. I. (2021). Removal of azo dyes – tartrazine, carmoisine, and Allura Red – from wastewater using Spirulina biomass-immobilized alginate beads: Equilibrium, kinetics, thermodynamics, desorption, and reusability. Desalination and Water Treatment, 220, 431–445.
Saratale, R. G., Saratale, G. D., Chang, J. S., & Govindwar, S. P. (2011). Bacterial decolorization and degradation of azo dyes: A review. Journal of the Taiwan Institute of Chemical Engineers, 42(1), 138–157.
Saravanan, P., Josephraj, J., & Pushpa Thillainayagam, B. (2021). A comprehensive analysis of biosorptive removal of basic dyes by different biosorbents. Environmental Nanotechnology, Monitoring & Management, 16, 100560.
Satpati, G. G., Gupta, S., Biswas, R. K., Choudhury, A. K., Kim, J.-W., & Davoodbasha, M. (2023). Microalgae mediated bioremediation of polycyclic aromatic hydrocarbons: Strategies, advancement and regulations. Chemosphere, 344, 140337.
Senturk, T. (2024). Phycoremediation of Phenolphytalein, Indigo Carmine, Methyl Orange and Eriochrome Black T By Using Chlamydomonas and Chlorella sp. (Chlorophyta). Turkish Journal of Fisheries and Aquatic Sciences, 24(6).
Sigamani, S., Chinnasamy, R., Sathiyamoorthy, T., Narayanasamy, M., Nagarajan, S., Ramamurthy, D., & Natarajan, H. (2024). Eco-friendly biodegradation of synthetic dyes using algae and its toxicological assessment on Clarias gariepinus. Biomass Conversion and Biorefinery, 14(16), 19835–19848.
Sinyoung, S., Jeeraro, A., Udomkun, P., Kunchariyakun, K., Graham, M., & Kaewlom, P. (2025). Enhancing CO2 Sequestration Through Corn Stalk Biochar-Enhanced Mortar: A Synergistic Approach with Algal Growth for Carbon Capture Applications. Sustainability, 17(1), Article 1.
Sivalingam, S., & Gopal, V. (2023). Coagulation Study on Extracted Algal Alginate from Red Algae as Natural Coagulant for Remediation of Textile Dye Congo Red. Environment and Natural Resources Journal, 21(2), Article 2.
Škrovánková, S. (2011). Seaweed Vitamins as Nutraceuticals. In Advances in Food and Nutrition Research (Vol. 64, pp. 357–369). Elsevier. 
Sompark, C., Singkhonrat, J., & Sakkayawong, N. (2021). Biotransformation of Reactive Red 141 by Paenibacillus terrigena KKW2-005 and Examination of Product Toxicity. Journal of Microbiology and Biotechnology, 31(7), 967–977.
Srimongkol, P., Sangtanoo, P., Songserm, P., Watsuntorn, W., & Karnchanatat, A. (2022). Microalgae-based wastewater treatment for developing economic and environmental sustainability: Current status and future prospects. Frontiers in Bioengineering and Biotechnology, 10, 904046.
Subhan, H., Alam, S., Shah, L. A., Ali, M. W., & Farooq, M. (2021). Sodium alginate grafted poly(N-vinyl formamide-co-acrylic acid)-bentonite clay hybrid hydrogel for sorptive removal of methylene green from wastewater. Colloids and Surfaces A: Physicochemical and Engineering Aspects, 611, 125853.
Sun, W., Sun, W., & Wang, Y. (2019). Biosorption of Direct Fast Scarlet 4BS from aqueous solution using the green-tide-causing marine algae Enteromorpha prolifera. Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, 223, 117347.
Tang, C., Chen, Z., Huang, Y., Solyanikova, I. P., Mohan, S. V., Chen, H., & Wu, Y. (2023). Occurrence and potential harms of organochlorine pesticides (OCPs) in environment and their removal by periphyton. Critical Reviews in Environmental Science and Technology, 53(22), 1957–1981.
Tang, C.-C., Tian, Y., Liang, H., Zuo, W., Wang, Z.-W., Zhang, J., & He, Z.-W. (2018). Enhanced nitrogen and phosphorus removal from domestic wastewater via algae-assisted sequencing batch biofilm reactor. Bioresource Technology, 250, 185–190.
Tiwari. (2012). Decolorization of Distillery Effluent by Thermotolerant Bacillus subtilis. American Journal of Applied Sciences, 9(6), 798–806.
Touliabah, H. E.-S., El-Sheekh, M. M., Ismail, M. M., & El-Kassas, H. (2022). A Review of Microalgae- and Cyanobacteria-Based Biodegradation of Organic Pollutants. Molecules, 27(3), Article 3.
Umama, B. R., Kakon, C., Jarrin, Y. S., & Saidur, R. (2021). Impact of Industrial Waste on Natural Resources: A Review in the Context of Bangladesh. Current World Environment, Volume 16(Issue 2).
Vasseghian, Y., Nadagouda, M. M., & Aminabhavi, T. M. (2024). Biochar-enhanced bioremediation of eutrophic waters impacted by algal blooms. Journal of Environmental Management, 367, 122044.
Venkata Mohan, S., Nikhil, G. N., Chiranjeevi, P., Nagendranatha Reddy, C., Rohit, M. V., Kumar, A. N., & Sarkar, O. (2016). Waste biorefinery models towards sustainable circular bioeconomy: Critical review and future perspectives. Bioresource Technology, 215, 2–12.
Vijayaraghavan, G., & Shanthakumar, S. (2015). Removal of sulphur black dye from its aqueous solution using alginate from Sargassum sp. (Brown algae) as a coagulant. Environmental Progress & Sustainable Energy, 34(5), 1427–1434.
Vijayaraghavan, G., & Shanthakumar, S. (2016). Performance study on algal alginate as natural coagulant for the removal of Congo red dye. Desalination and Water Treatment, 57(14), 6384–6392.
Vijayaraghavan, G., & Shanthakumar, S. (2018). Effective removal of Reactive Magenta dye in textile effluent by coagulation using algal alginate. Desalination and Water Treatment, 121, 22–27.
Vijayaraghavan, G., & Shanthakumar, S. (2020). Removal of Crystal violet dye in textile effluent by coagulation using algal alginate from brown algae Sargassum sp. Desalination and Water Treatment, 196, 402–408.
Waqas, R., Arshad, M., Asghar, H. N., & Asghar, M. (2015). Optimization of Factors for Enhanced Phycoremediation of Reactive Blue Azo Dye. International Journal of Agriculture and Biology, 17(4), 803–808. 
Yin, C.-Y. (2010). Emerging usage of plant-based coagulants for water and wastewater treatment. Process Biochemistry, 45(9), 1437–1444. https://doi.org/10.1016/j.procbio.2010.05.030
Youssef, E. E., Beshay, B. Y., Tonbol, K., & Makled, S. O. (2023). Biological activities and biosorption potential of red algae (Corallina officinalis) to remove toxic malachite green dye. Scientific Reports, 13(1), 13836.
Yu, C., Tang, J., Su, H., Huang, J., Liu, F., Wang, L., & Sun, H. (2022). Development of a novel biochar/iron oxide composite from green algae for bisphenol-A removal: Adsorption and Fenton-like reaction. Environmental Technology & Innovation, 28, 102647.
Zhang, P., Yang, M., Lan, J., Huang, Y., Zhang, J., Huang, S., Yang, Y., & Ru, J. (2023). Water Quality Degradation Due to Heavy Metal Contamination: Health Impacts and Eco-Friendly Approaches for Heavy Metal Remediation. Toxics, 11(10), 828. https://doi.org/10.3390/toxics11100828
Zubair, S., & Mujtaba, G. (2009). Comparison of efficacy of topical 2% liquiritin, topical 4% liquiritin and topical 4% hydroquinone in the management of melasma. Journal of Pakistan Association of Dermatologists, 19(3), Article 3.