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Khumalo GP, Loa-Kum-Cheung W, Van Wyk BE, Feng Y, Cock IE. Leaf extracts of eight selected southern African medicinal plants modulate pro-inflammatory cytokine secretion in LPS-stimulated RAW 264.7 macrophages. Inflammopharmacology 2024; 32:1607-1620. [PMID: 38310564 PMCID: PMC11006729 DOI: 10.1007/s10787-023-01420-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2023] [Accepted: 12/22/2023] [Indexed: 02/06/2024]
Abstract
This study investigates the anti-inflammatory properties of extracts prepared from the leaves of eight southern African medicinal plants used traditionally to treat inflammation and pain. The inhibitory effect of aqueous and ethanol extracts on the release of pro-inflammatory cytokines was determined in lipopolysaccharide (LPS) stimulated and unstimulated RAW 264.7 murine macrophage cells. The levels of interleukin (IL)-1β, IL-6, tumour necrosis factor-α (TNF-α), interferon-gamma (IFN-γ), monocyte chemoattractant protein 1 (MCP-1) and macrophage inflammatory protein (MIP)-2 release were determined using cytokine multiplex-bead assays. The ethanol extracts of Melianthus comosus Vahl (commonly known as honey flower), Tetradenia riparia (Hochst.) Codd (misty plume bush) and Warburgia salutaris (G. Bertol.) Chiov. (pepper-bark tree), demonstrated the most significant inhibitory activity, with over 50-fold inhibition of IL-1β, IL-6 and TNF-α levels in LPS-stimulated RAW 264.7 macrophages. The aqueous extract of M. comosus also significantly inhibited the secretion of all the tested cytokines and chemokines. Phytochemical investigation of M. comosus ethanol leaf extract using ultra-high-performance liquid chromatography coupled with high-resolution mass spectrometry (UHPLC-HRMS) led to the detection of crassolide, deoxylimonoic acid D-ring-lactone, 2-hydroxynonanoic acid and 5-noniloxytryptamine. To the best of our knowledge, the cytokine inhibition properties of most of the medicinal plants screened in this study are reported for the first time. Our results support the use of southern African medicinal plants as anti-inflammatory remedies and provide an insight into the immunomodulatory mechanisms of action.
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Affiliation(s)
- Gugulethu P Khumalo
- Centre for Planetary Health and Food Security, Nathan Campus, Griffith University, 170 Kessels Rd, Nathan, QLD, 4111, Australia
- School of Environment and Science, Nathan Campus, Griffith University, 170 Kessels Rd, Nathan, QLD, 4111, Australia
| | - Wendy Loa-Kum-Cheung
- Griffith Institute for Drug Discovery, Griffith University, 46 Don Young Rd, Nathan, QLD, 4111, Australia
| | - Ben-Erik Van Wyk
- Department of Botany and Plant Biotechnology, University of Johannesburg, Auckland Park, P.O. Box 524, Johannesburg, 2006, South Africa
| | - Yunjiang Feng
- School of Environment and Science, Nathan Campus, Griffith University, 170 Kessels Rd, Nathan, QLD, 4111, Australia
- Griffith Institute for Drug Discovery, Griffith University, 46 Don Young Rd, Nathan, QLD, 4111, Australia
| | - Ian E Cock
- Centre for Planetary Health and Food Security, Nathan Campus, Griffith University, 170 Kessels Rd, Nathan, QLD, 4111, Australia.
- School of Environment and Science, Nathan Campus, Griffith University, 170 Kessels Rd, Nathan, QLD, 4111, Australia.
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Khumalo GP, Nguyen T, Van Wyk BE, Feng Y, Cock IE. Inhibition of pro-inflammatory cytokines by selected southern African medicinal plants in LPS-stimulated RAW 264.7 macrophages. J Ethnopharmacol 2024; 319:117268. [PMID: 37797874 DOI: 10.1016/j.jep.2023.117268] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/15/2023] [Revised: 09/18/2023] [Accepted: 09/30/2023] [Indexed: 10/07/2023]
Abstract
ETHNOPHARMACOLOGICAL RELEVANCE Bark is frequently used in southern African traditional medicine to treat inflammation, yet it remains to be rigorously examined for its immunological and anti-inflammatory activity. AIM OF THE STUDY Barks obtained from ten important and popular southern Africa plants were evaluated for their anti-inflammatory and immunomodulatory properties against the secretion of some pro-inflammatory cytokines (interleukin (IL)-1β, IL-6, tumour necrosis factor-α (TNF-α), and interferon-gamma (IFN-γ) as well as chemokines (monocyte chemoattractant protein 1 (MCP-1) and macrophage inflammatory protein (MIP)-2) in murine RAW 264.7 macrophages. MATERIALS AND METHODS The inhibitory effects of aqueous and ethanol extracts were determined using cytokine multiplex-bead assays in lipopolysaccharide (LPS)-stimulated and unstimulated RAW 264.7 cells. RESULTS Overall, the ethanol extracts were more potent cytokine inhibitors compared to the aqueous extracts. The LPS-stimulated cells treated with the ethanol extracts of Erythrina lysistemon Hutch., Pterocelastrus rostratus Walp. Syzygium cordatum Hochst. ex Krauss and Warburgia salutaris (G. Bertol.) Chiov., demonstrated significant (p < 0.005) inhibition up to 85% of IL-1β, IL-6, and TNF-α secretion compared to the LPS control. Additionally, P. rostratus and S. cordatum aqueous bark extracts substantially decreased the secretion of all the tested cytokines and chemokines. Chemical investigation of the S. cordatum extract resulted in the identification of four ellagic acid derivatives: ellagic acid 4-O-α-rhamnopyranoside (1), ellagic acid 4-O-α-4″-acetylrhamnopyranoside (2), 3-O-methylellagic acid 4'-O-α-3″-O-acetylrhamnopyranoside (3) and 3-O-methylellagic acid 4'-O-α-4″-O-acetylrhamnopyranoside (4), along with mixtures of ellagic acid 4-O-α-2″-acetylrhamnopyranoside (5), ellagic acid 4-O-α-3″-acetylrhamnopyranoside (6) and ellagic acid (7). Their structures were confirmed by mass spectrometry, NMR spectroscopy, and comparison with data from literature. CONCLUSION The cytokine inhibition properties of most of the medicinal plants screened herein are reported for the first time. Our results provide insights into the mechanism of action by which the selected southern African medicinal plants regulate inflammation.
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Affiliation(s)
- Gugulethu P Khumalo
- Centre for Planetary Health and Food Security, Nathan Campus, Griffith University, 170 Kessels Rd, Nathan, Queensland, 4111, Australia; School of Environment and Science, Nathan Campus, Griffith University, 170 Kessels Rd, Nathan, Queensland, 4111, Australia
| | - Thanh Nguyen
- Griffith Institute for Drug Discovery, Griffith University, 46 Don Young Rd, Nathan, Queensland, 4111, Australia
| | - Ben-Erik Van Wyk
- Department of Botany and Plant Biotechnology, University of Johannesburg, P.O. Box 524, Auckland Park 2006, Johannesburg, South Africa
| | - Yunjiang Feng
- School of Environment and Science, Nathan Campus, Griffith University, 170 Kessels Rd, Nathan, Queensland, 4111, Australia; Griffith Institute for Drug Discovery, Griffith University, 46 Don Young Rd, Nathan, Queensland, 4111, Australia
| | - Ian E Cock
- Centre for Planetary Health and Food Security, Nathan Campus, Griffith University, 170 Kessels Rd, Nathan, Queensland, 4111, Australia; School of Environment and Science, Nathan Campus, Griffith University, 170 Kessels Rd, Nathan, Queensland, 4111, Australia.
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Khumalo GP, Van Wyk BE, Feng Y, Cock IE. A review of the traditional use of southern African medicinal plants for the treatment of inflammation and inflammatory pain. J Ethnopharmacol 2022; 283:114436. [PMID: 34289396 DOI: 10.1016/j.jep.2021.114436] [Citation(s) in RCA: 28] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/15/2021] [Revised: 07/14/2021] [Accepted: 07/16/2021] [Indexed: 06/13/2023]
Abstract
ETHNOPHARMACOLOGICAL RELEVANCE Inflammation is a serious global concern due to its debilitating symptoms, resulting in considerable suffering and lost productivity. Chronic and auto-immune inflammatory diseases are of particular concern. Several pharmaceutical therapies are already available. However, the use of non-steroidal anti-inflammatory drugs (NSAID's) is accompanied by harmful and toxic side effects. Hence, the search for safer alternative therapeutics with limited side effects is imperative. The use of medicinal plants is common practice amongst the southern African population and may provide targets for drug development. AIM OF THE STUDY This study aims to review and document the medicinal uses and pharmacological properties of southern African medicinal plants used for inflammation and pain-related ailments. MATERIAL AND METHODS An extensive literature review was undertaken to identify southern African plants used traditionally to treat inflammation. A variety of ethnobotanical books and grey literature, as well as ScienceDirect, Google Scholar and Scopus search engines were used as sources of information. RESULTS This review identified 555 medicinal plants from 118 families which were traditionally used in southern Africa to treat inflammation and pain. Fabaceae was the most prominent family with 63 species, followed by Asteraceae (54 species) and Apocynaceae (33 species). The top category of ailments indicated include non-specific inflammation with 150 species, followed by inflammatory pain (148 species), headache (114 species) and toothache (114 species). CONCLUSION Despite a large number of southern African medicinal plants used to treat inflammation and pain, relatively few have been screened for their anti-inflammatory properties. Furthermore, biologically active plant extracts have been tested against relatively few inflammatory markers and considerable further work is required.
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Affiliation(s)
- Gugulethu P Khumalo
- Environmental Futures Research Institute, Nathan Campus, Griffith University, 170 Kessels Rd, Nathan, Queensland, 4111, Australia; School of Environment and Science, Nathan Campus, Griffith University, 170 Kessels Rd, Nathan, Queensland, 4111, Australia; Griffith Research Institute for Drug Discovery, Griffith University, 46 Don Young Rd, Nathan, Queensland, 4111, Australia
| | - Ben Erik Van Wyk
- Department of Botany and Plant Biotechnology, University of Johannesburg, P.O. Box 524, Auckland Park, 2006, Johannesburg, South Africa
| | - Yunjiang Feng
- School of Environment and Science, Nathan Campus, Griffith University, 170 Kessels Rd, Nathan, Queensland, 4111, Australia; Griffith Research Institute for Drug Discovery, Griffith University, 46 Don Young Rd, Nathan, Queensland, 4111, Australia
| | - Ian E Cock
- Environmental Futures Research Institute, Nathan Campus, Griffith University, 170 Kessels Rd, Nathan, Queensland, 4111, Australia; School of Environment and Science, Nathan Campus, Griffith University, 170 Kessels Rd, Nathan, Queensland, 4111, Australia.
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Khumalo GP, Sadgrove NJ, Van Vuuren SF, Van Wyk BE. South Africa's Best BARK Medicines Prescribed at the Johannesburg Muthi Markets for Skin, Gut, and Lung Infections: MIC's and Brine Shrimp Lethality. Antibiotics (Basel) 2021; 10:681. [PMID: 34200286 PMCID: PMC8227155 DOI: 10.3390/antibiotics10060681] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2021] [Revised: 06/03/2021] [Accepted: 06/05/2021] [Indexed: 12/03/2022] Open
Abstract
Indigenous trade of medicinal plants in South Africa is a multi-million-rand industry and is still highly relevant in terms of primary health care. The purpose of this study was to identify today's most traded medicinal barks, traditionally and contemporaneously used for dermatological, gastrointestinal, and respiratory tract infections; then, to investigate the antimicrobial activity and toxicity of the respective extracts and interpret outcomes in light of pharmacokinetics. Thirty-one popularly traded medicinal barks were purchased from the Faraday and Kwa Mai-Mai markets in Johannesburg, South Africa. Information on the medicinal uses of bark-based medicines in modern commerce was recorded from randomly selected traders. The minimum inhibitory concentration (MIC) method was used for antimicrobial screening, and brine shrimp lethality was used to determine toxicity. New medicinal uses were recorded for 14 bark species. Plants demonstrating some broad-spectrum activities against tested bacteria include Elaeodendron transvaalense, Erythrina lysistemon, Garcinia livingstonei, Pterocelastrus rostratus, Rapanea melanophloeos, Schotia brachypetala, Sclerocarya birrea, and Ziziphus mucronata. The lowest MIC value of 0.004 mg/mL was observed against Staphylococcus epidermidis for a dichloromethane bark extract of E. lysistemon. The tested medicinal barks were shown to be non-toxic against the Artemia nauplii (brine shrimp) bioassay, except for a methanol extract from Trichilia emetica (69.52% mortality). Bacterial inhibition of bark extracts with minimal associated toxicity is consistent with the safety and valuable use of medicinal barks for local muthi market customers. Antimicrobial outcomes against skin and gastrointestinal pathogens are feasible because mere contact-inhibition is required in vivo; however, MIC values against respiratory pathogens require further explaining from a pharmacokinetics or pharmacodynamics perspective, particularly for ingested rather than smoked therapies.
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Affiliation(s)
- Gugulethu P. Khumalo
- Department of Botany and Plant Biotechnology, University of Johannesburg, P.O. Box 524, Auckland Park 2006, South Africa;
| | - Nicholas J. Sadgrove
- Department of Botany and Plant Biotechnology, University of Johannesburg, P.O. Box 524, Auckland Park 2006, South Africa;
- Jodrell Science Laboratory, Royal Botanic Gardens Kew, Richmond, Surrey TW9 3DS, UK
| | - Sandy F. Van Vuuren
- Department of Pharmacy and Pharmacology, Faculty of Health Sciences, University of the Witwatersrand, 7 York Road, Park Town 2193, South Africa;
| | - Ben-Erik Van Wyk
- Department of Botany and Plant Biotechnology, University of Johannesburg, P.O. Box 524, Auckland Park 2006, South Africa;
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