Phytochemical Profiles and Free Radical-Scavenging Properties of Extracts and Smoke-Water from Amakamo Vessel Fumigation Plants

Norah Gulaita; Rebecca Nalubega; Immaculate Nakalembe; Francis Ejobi; Jesca Nakavuma Lukanga

doi:10.70851/jfines.2026.3(3).362.371

Authors

Dr. Norah Gulaita Makerere University, Kampala Author https://orcid.org/0009-0002-7586-5239
Dr. Rebecca Nalubega Makerere University Author
Dr. Immaculate Nakalembe Makerere University , Makerere University, Kampala Author
Assoc. Professor Francis Ejobi Author
Assoc. Professor Jesca Lukanga Nakavuma Author

DOI:

https://doi.org/10.70851/jfines.2026.3(3).362.371

Keywords:

Combretum molle, Rhus natalensis, Gardenia ternifolia, Fermented milk, antioxidant activity, vessel smoking

Abstract

Traditional amakamo processors in Kiruhura District, Uganda, fumigate milk fermentation vessels with certain plant stem-wood, but information on the phytochemical characteristics of the wood extracts and smoke-derived aqueous preparations remains limited. The study descriptively analysed methanolic, hydroethanolic and smoke-water extracts (SWE) of Rhus natalensis, Combretum molle and Gardenia ternifolia. Three independent stem-wood batches were collected for each species and independently extracted with methanol and 50% ethanol. Three independent SWE preparations were produced using individual smoked gourds. Qualitative phytochemical screening, total phenolic content (TPC), total flavonoid content (TFC), percentage DPPH inhibition and IC₅₀ were determined and summarized as mean ±SD (n=3 independent preparations). Extraction yields for methanol ranged from 15.14±0.58% to 23.01±0.10%, while hydroethanolic yields ranged from 16.96±0.12% to 23.76±0.20%. Phenols and flavonoids were detected in all preparations. Combretum molle SWE had the highest mean TPC (387.27± 0.00 mg GAE/g) and TFC (7.59 ±0.62 mg RE/g) among all preparations. Hydroethanolic Combretum molle exhibited the highest mean % DPPH inhibition (97.33 ±0.58%), whereas methanolic Combretum molle had the lowest IC₅₀(0.040 ±0.002 mg/mL). The findings demonstrate that phytochemical and radical-scavenging profiles varied by plant species and preparation method. Because SWE was generated through smoldering, smoke deposition and aqueous recovery rather than direct solvent extraction, its high numerical TPC/TFC values should not be interpreted as evidence of superior extraction efficiency. More studies are required to further characterise the chemical constituents of smoke and evaluate the effects of vessel fumigation on amakamo quality and safety.

Author Biographies

Dr. Norah Gulaita, Makerere University, Kampala

Assistant Lecturer,

Department of Anatomy and Physiological Sciences, College of Veterinary Medicine, Animal Resources and Biosecurity, Makerere University, P. O. Box 7062, Kampala, Uganda
Dr. Rebecca Nalubega, Makerere University

Department of Anatomy and Physiological Sciences, College of Veterinary Medicine, Animal Resources and Biosecurity, Makerere University, P. O. Box 7062, Kampala, Uganda
Dr. Immaculate Nakalembe, Makerere University, Makerere University, Kampala

Senior Lecturer,

Department of Veterinary Pharmacy and Clinical Studies, College of Veterinary Medicine, Animal Resources and Biosecurity, Makerere University, P. O. Box 7062, Kampala, Uganda
Assoc. Professor Francis Ejobi

Assoc. Professor and Director Department of Graduate Studies, Research and Innovations, Soroti University, P.O Box 211, Soroti, Uganda
Assoc. Professor Jesca Lukanga Nakavuma

Assoc. Professor, Department of Biomedical Laboratory Technology and Molecular Biology, College of Veterinary Medicine, Animal Resources and Biosecurity, Makerere University, P. O. Box 7062, Kampala, Uganda

References

Akar, Z., Küçük, M., & Doğan, H. (2017). A new colorimetric DPPH• scavenging activity method with no need for a spectrophotometer applied on synthetic and natural antioxidants and medicinal herbs. Journal of enzyme inhibition and medicinal chemistry, 32(1), 640-647. https://doi.org/10.1080/14756366.2017.1284068

Alqasoumi, S. I., Basudan, O. A., Alam, P., & Abdel-Kader, M. S. (2016). Antioxidant study of flavonoid derivatives from the aerial parts of Rhus natalensis growing in Saudi Arabia. Pakistan Journal of Pharmaceutical Sciences, 29(1), 97.

Anywar, G., Kakudidi, E., Byamukama, R., Mukonzo, J., Schubert, A., Oryem-Origa, H., & Jassoy, C. (2021). A review of the toxicity and phytochemistry of medicinal plant species used by herbalists in treating people living with HIV/AIDS in Uganda. Frontiers in pharmacology, 12, 615147. https://doi.org/10.3389/fphar.2021.615147

Bravo-Monzón, A. E., Montiel-González, C., Avila-Cabadilla, L. D., & Alvarez-Añorve, M. Y. (2022). Small-scale determination of total phenols, tannins, and flavonoids from foliar tissue using colorimetric assays. Research Square 1-8. https://doi.org/10.21203/rs.3.pex-1234/v2

Camara, A., Diouf, A., Gaye, A. A., Diallo, I., Diop, B., & Mouhamadou, F. (2023). Phytochemical study and dosage of polyphenols and flavonoids of the methanolic extract of the leaves and stem bark of Gardenia ternifolia. International Journal of Science and Research Archive, 9, 291-296. https://doi.org/10.30574/ijsra.2023.9.2.0545

Dai, J., & Mumper, R. J. (2010). Plant phenolics: extraction, analysis and their antioxidant and anticancer properties. Molecules, 15(10), 7313-7352. https://doi.org/10.3390/molecules15107313

Granato, D., Santos, J. S., Salem, R. D., Mortazavian, A. M., Rocha, R. S., & Cruz, A. G. (2018). Effects of herbal extracts on quality traits of yogurts, cheeses, fermented milks, and ice creams: a technological perspective. Current Opinion in Food Science, 19, 1-7. https://doi.org/10.1016/j.cofs.2017.11.013

Gulaita, N., Nalubega, R., Nakalembe, I., Ejobi, F., Nabatanzi, A., & Nakavuma, J. L. (2025). Plants and procedures used for traditional processing of sour milk (Amakamo) by the Bahima of Kiruhura District, Uganda. East African Journal of Science, Technology and Innovation, 7(1). https://doi.org/10.37425/bt2x4057

Karenzi, E., Mashaku, A., Nshimiyimana, A. M., Munyanganizi, B., & Thonart, P. (2013). Kivuguto traditional fermented milk and the dairy industry in Rwanda. A review. Biotechnolgy, Agronomy, Society and Environment, 17(2), 383-391.

Kwaghvihi, O. B., Akombo, P. M., & Omeji, S. (2020). Effect of wood smoke on the quality of smoked fish. Mediterranean Journal of Basic and Applied Sciences 4(2), 72-82. https://doi.org/10.46382/MJBAS.2020.4207

Lee, J.-E., Jayakody, J. T. M., Kim, J.-I., Jeong, J.-W., Choi, K.-M., Kim, T.-S., Seo, C., Azimi, I., Hyun, J., & Ryu, B. (2024). The influence of solvent choice on the extraction of bioactive compounds from Asteraceae: A comparative review. Foods, 13(19), 3151. https://doi.org/10.3390/foods13193151

Lingbeck, J. M., Cordero, P., O'Bryan, C. A., Johnson, M. G., Ricke, S. C., & Crandall, P. G. (2014). Functionality of liquid smoke as an all-natural antimicrobial in food preservation. Meat Science, 97(2), 197-206. https://doi.org/10.1016/j.meatsci.2014.02.003

Mahmoud, A. E.-A. (2023). Plant extracts and essential oils in the dairy industry: A review. Foods and Raw materials, 11(2), 321-337. https://doi.org/10.21603/2308-4057-2023-1-547

Nizio, E., Czwartkowski, K., & Niedbała, G. (2023). Impact of smoking technology on the quality of food products: absorption of polycyclic aromatic Hydrocarbons (PAHs) by food products during smoking. Sustainability, 15(24), 16890. https://doi.org/10.3390/su152416890

Ntshanka, N. M., Ejidike, I. P., Mthunzi, F. M., Moloto, M. J., & Mubiayi, K. P. (2020). Investigation into the phytochemical profile, antioxidant and antibacterial potentials of Combretum molle and Acacia mearnsii leaf parts. Biomedical and Pharmacology Journal, 13(4), 1683-1694. https://doi.org/10.13005/bpj/2043

Parusnath, M., Naidoo, Y., Singh, M., Rihan, H., & Dewir, Y. H. (2023). Phytochemical composition of Combretum molle (R. Br. ex G. Don.) Engl. & Diels leaf and stem extracts. Plants, 12(8), 1702. https://doi.org/10.3390/plants12081702

Parveen, B., Rajinikanth, V., & Narayanan, M. (2025). Natural plant antioxidants for food preservation and emerging trends in nutraceutical applications. Discover Applied Sciences, 7(8), 845. https://doi.org/10.1007/s42452-025-07464-6

Pavun, L., Uskokovic-Marković, S., Jelikic-Stankov, M., Đikanović, D., & Durdević, P. (2018). Determination of flavonoids and total polyphenol contents in commercial apple juices. Czech Journal of Food Sciences, 36(3), 233-238. https://doi.org/10.17221/211/2017-CJFS

Silén, H., Salih, E. Y., Mgbeahuruike, E. E., & Fyhrqvist, P. (2023). Ethnopharmacology, antimicrobial potency, and phytochemistry of African Combretum and Pteleopsis species (Combretaceae): A review. Antibiotics, 12(2), 264. https://doi.org/10.3390/antibiotics12020264

Sokamte tegang, A., Mbougueng, P. D., Sachindra, N. M., Nodem, N. F. D., & Ngoune, L. T. (2020). Characterization of volatile compounds of liquid smoke flavourings from some tropical hardwoods. Scientific African, 8, e00443. https://doi.org/10.1016/j.sciaf.2020.e00443

Sorescu, A. A., Nuta, A., Ion, R. M., & Iancu, L. (2018). Qualitative analysis of phytochemicals from sea buckthorn and gooseberry. Phytochemicals–Source of Antioxidants and Role in Disease Prevention, 13, 161-177. https://doi.org/10.5772/intechopen.77365

Suryani, R., Daradwinta, R., Az-Zahra, S., Rahmah, S. A., Rizal, W. A., Jatmiko, T. H., Apriyana, W., & Purwestri, Y. A. (2022). Antioxidant activity, total phenolic content, and chemical composition of liquid smoke derived from wood sawdust. 7th International Conference on Biological Science (ICBS 2021),

Tamene, S., Negash, M., Makonda, F. B., & Chiwona-Karltun, L. (2024). Influence of socio-demographic factors on medicinal plant knowledge among three selected ethnic groups in south-central Ethiopia. Journal of Ethnobiology and Ethnomedicine, 20(1), 29. https://doi.org/10.1186/s13002-024-00672-1

Tano-Debrah, K., Amamoo-Otchere, J., Karikari, A., & Diako, C. (2007). Quality characteristics and safety of smoke-flavoured water. Food and chemical toxicology, 45(6), 962-970. https://doi.org/10.1016/j.fct.2006.11.017

Toledo, R. T. (2007). Wood smoke components and functional properties. Smoked seafood safety, 55.

Ullah, H., Hussain, Y., Santarcangelo, C., Baldi, A., Di Minno, A., Khan, H., Xiao, J., & Daglia, M. (2022). Natural polyphenols for the preservation of meat and dairy products. Molecules, 27(6), 1906. https://doi.org/10.3390/molecules27061906

Wanjala, N. W., Matofari, J. W., & Nduko, J. M. (2016). Antimicrobial effect of smoking milk handling containers’ inner surfaces as a preservation method in pastoral systems in Kenya. Pastoralism, 6(17), 1-7. https://doi.org/10.1186/s13570-016-0064-y

Wayua, F. O., Okoth, M. W., & Wangoh, J. (2012). Survey of postharvest handling, preservation and processing practices along the camel milk chain in Isiolo district, Kenya. African Journal of Food, Agriculture, Nutrition and Development, 12(7), 6897-6912.

Wu, Y., Jiang, L., Ran, W., Zhong, K., Zhao, Y., & Gao, H. (2024). Antimicrobial activities of natural flavonoids against foodborne pathogens and their application in food industry. Food Chemistry, 460, 140476. https://doi.org/10.1016/j.foodchem.2024.140476

Zhang, Q. W., Lin, L. G., & Ye, W. C. (2018). Techniques for extraction and isolation of natural products: A comprehensive review. Chinese medicine, 13(1), 20. https://doi.org/10.1186/s13020-018-0177-x

Zhang, Y., Silcock, P., Jones, J. R., & Eyres, G. T. (2020). Changes in wood smoke volatile composition by manipulating the smoke generation conditions. Journal of analytical and applied pyrolysis, 148, 104769. https://doi.org/10.1016/j.jaap.2019.104769