ReviewArtemisia afra, a controversial herbal remedy or a treasure trove of new drugs?
Graphical abstract
Section snippets
Structure of this review
Since our previous review of Artemisia afra Jacq. ex Willd (Liu et al., 2009), a number of recent developments prompted us to review all available literature published since 2009. The two most notable developments were a court case in 2017, where a South African herbal company took the Medicine Control Council (MCC) - now known as the South African Health Products Regulatory Authority (SAHPRA) - to court (https://www.iol.co.za/pretoria-news/malaria-muti-battle-in-court-12030332) after the MCC
Introduction and botanical aspects
The genus Artemisia (Asteraceae) consists of approximately 500 species distributed across several continents throughout the world (Bora and Sharma, 2011; Avula et al., 2009). Artemisia annua L. and A. absinthium L. are probably two of the best known species in this family, with the former being the main source of the antimalarial compound artemisinin, and the latter the main ingredient of ‘absinthe’ or ‘bitter’, which has been used for centuries in medicinal preparations and alcoholic
Ethnopharmacology of Artemisia afra
Artemisia afra is one of the most commonly used plants in traditional medicine in South Africa. The treatment of a wide ranging and unrelated list of health conditions and symptoms indicates that A. afra can, or should be considered a panacea. According to Watt and Breyer-Brandwijk (1962), “the usual preparation is an infusion or decoction, often made syrupy by the addition of sugar, especially when the medicine is for bronchial troubles.” It is used to treat coughs and colds, chills,
Phytochemical analysis of Artemisia afra
In our previous review paper, we tabulated all the volatile and non-volatile compounds that have been identified in A. afra (Liu et al., 2009). Since 2009, only a few publications reported on the identification of phytochemicals in A. afra. Liu et al. (2010) reported three new phenylpropanoids for this species, and More et al. (2012) identified six known compounds. Venables et al. (2016) isolated a new isoalantolactone whereas Braünlich et al. (2018) focussed on the main types of
In vitro and in vivo toxicity of Artemisia afra
Little work has been done focusing on the toxicity of A. afra extracts. In 2009 an in vivo study in rats established that acute administration of A. afra displayed no toxicity with low potential for toxicity after chronic administration (Ntutela et al., 2009). Lall and Kishore (2014) reviewed plant species used for skin care and reported that A. afra extracts gave a half maximal inhibitory concentration (IC50) value of 16.95 μg/mL on McCoy fibroblast cell line in a MTT toxicity assay. A 2015
Surveys and general biological activity
A relatively large number of surveys and studies testing A. afra extracts in various in vitro and in vivo bioassays have been conducted over the past decade. Sunmonu and Afolayan (2010) studied the cardio protective effect of an aqueous extract of A. afra in isoproterenol-induced myocardial injured rats. They found that A. afra offers some cardioprotective effect. Wintola and Afolayan (2010) conducted a survey of the most common plants used for the treatment of constipation and found that A.
Antimicrobial activity
Buwa and Afolayan (2009) screened A. afra extracts (water, ethanol and dichloromethane) against a number of microbial spp. and found that it showed moderate activity against all species tested. Van Vuuren et al. (2010) encapsulated the essential oil of A. afra and tested various formulations against four microbial species. They concluded that encapsulation did not improve the bioactivity of the essential oil of A. afra whilst other plant species did indeed show improved activity. Suliman et al.
In vitro activity
Since 2009 a number of in vitro studies were published relating to A. afra and its antiplasmodial activity. Liu et al. (2010) tested various extracts of the leaves of A. afra against P. falciparum and found that the non-polar extracts exhibited weak-moderate in vitro activity (8.4–12.35 μg/mL) whilst the tea infusion showed no activity at the highest concentration tested (20 μg/mL). The A. afra material used in this study contained no trace of the active compound artemisinin. Mokoka et al.
Conclusions and recommendations
Is A. afra a treasure chest of new drugs? Based on this review, the answer appears to be, no. Published research conducted over the last decade have shown that A. afra exhibits weak in vitro and in vivo biological activity. A point of concern is the antimycobacterial in vivo mice experiments where the researchers unfortunately concluded that A. afra show good in vitro activity and failed to conclude that based on the in vivo result, people might put their live at risk by forgoing effective
Conflicts of interest
The authors declare to have no conflicts of interest.
Acknowledgements
We like to thank Pharmacen, North West University, South Africa for start-up funds in order to complete this review.
References (65)
- et al.
Antidiabetic therapeutics from natural source: a systematic review
Biomed. Prev. Nutr.
(2014) - et al.
Polysaccharides from the South African medicinal plant Artemisia afra: structure and activity studies
Fitoterapia
(2018) Tuberculosis and nature's pharmacy of putative anti-tuberculosis agents
Acta Trop.
(2016)- et al.
Interactive antimicrobial and toxicity profiles of conventional antimicrobials with Southern African medicinal plants
South Afr. J. Bot.
(2014) - et al.
Are plants used for skin care in South Africa fully explored?
J. Ethnopharmacol.
(2014) - et al.
Metabolomic investigation of the ethnopharmacological use of Artemisia afra with NMR spectroscopy and multivariate data analysis
J. Ethnopharmacol.
(2010) - et al.
Artemisia afra: a potential flagship for African medicinal plants?
South Afr. J. Bot.
(2009) - et al.
Ethnopharmacology in overdrive: the remarkable anti-HIV activity of Artemisia annua
J. Ethnopharmacol.
(2012) - et al.
A preliminary investigation into the potential effect of Artemisia afra on growth and disease resistance in sub-adults of Oreochromis mossambicus
Aquaculture
(2018) - et al.
In vitro inhibition of Plasmodium falciparum early and late stage gametocyte viability by extracts from eight traditionally used South African plant species
J. Ethnopharmacol.
(2016)
Effect of Artemisia annua and Artemisia afra tea infusions on schistosomiasis in a large clinical trial
Phytomedicine
Artemisia annua and Artemisia afra tea infusions vs. artesunate-amodiaquine (ASAQ) in treating Plasmodium falciparum malaria in a large scale, double blind, randomized clinical trial
Phytomedicine
Antiplasmodial potential of traditional phytotherapy of some remedies used in treatment of malaria in Meru–Tharaka Nithi County of Kenya
J. Ethnopharmacol.
The activity of Artemisia spp. and their constituents against trypanosomasis
Phytomedicine
Volatile components of four Ethiopian Artemisia species extracts and their in vitro antitrypanosomal and cytotoxic activities
Phytomedicine
Efficacy of Artemisia afra phytotherapy in experimental tuberculosis
Tuberculosis
A survey of plants responsible for causing allergic contact dermatitis in the Amathole District, Eastern Cape, South Africa
South Afr. J. Bot.
Caspase-dependent apoptosis is induced by Artemisia afra Jacq. ex Willd in a mitochondria-dependent manner after G2/M arrest
South Afr. J. Bot.
Validating the in vitro antimicrobial activity of Artemisia afra in polyherbal combinations to treat respiratory infections
South Afr. J. Bot.
Metabolomic quality control of claimed anti-malarial Artemisia afra herbal remedy and A. afra and A. annua plant extracts
South Afr. J. Bot.
Do South African medicinal plants used traditionally to treat infections respond differently to resistant microbial strains?
South Afr. J. Bot.
Isoalantolactone, a sesquiterpene lactone from Artemisia afra Jacq. ex Willd and its in vitro mechanism of induced cell death in HeLa cells
South Afr. J. Bot.
In vivo studies on antidiabetic plants used in South African herbal medicine
J. Clin. Biochem. Nutr.
Artemisia afra Jacq. ameliorates oxidative stress in the pancreas of streptozotocin-induced diabetic Wistar rats
Biosc. Biotech. Biochem.
Protective role of Artemisia afra aqueous extract on tissue antioxidant defense systems in streptozotocin-induced diabetic rats
Afr. J. Tradit., Complementary Altern. Med.
Antioxidant and acetylcholinesterase-inhibitory properties of long-term stored medicinal plants
BMC Complement Altern. Med.
Comment on “Effect of Artemisia annua and Artemisia afra tea infusions on schistosomiasis in a large clinical trial”
Phytomedicine
Quantitative determination of flavonoids by column high-performance liquid chromatography with mass spectrometry and ultraviolet absorption detection in Artemisia afra and comparative studies with various species of Artemisia plants
J. AOAC Int.
The genus Artemisia: a comprehensive review
Pharm. Biol.
Antimicrobial activity of some medicinal plants used for the treatment of tuberculosis in the Eastern Cape Province, South Africa
Afr. J. Biotechnol.
Response to Argemi et al. 2019
Phytomedicine
Synthesis and characterisation of silver nanoparticles using leaf extract of Artemisia afra and their in vitro antimicrobial and antioxidant activities
IET Nanobiotechnol.
Cited by (35)
Artemisia extracts differ from artemisinin effects on human hepatic CYP450s 2B6 and 3A4 in vitro
2022, Journal of EthnopharmacologyIn vitro antischistosomal activity of Artemisia annua and Artemisia afra extracts
2022, Phytomedicine PlusCitation Excerpt :A mixture of the reference compounds was also analysed using these two chromatographic systems. The choice of reference compounds was based on literature regarding the major compounds found in A. annua infusions (Van der Kooy et al. 2008; Mouton and Van der Kooy, 2014; Du Toit and Van der Kooy, 2019). A validated method using an Agilent Ultivo electrospray ionisation triple quadrupole mass spectrometer was used to analyse all samples for artemisinin content (Lee et al., 2022).
Molecular modelling identification of phytocompounds from selected African botanicals as promising therapeutics against druggable human host cell targets of SARS-CoV-2
2022, Journal of Molecular Graphics and ModellingValidating a sensitive LCMS method for the quantitation of artemisinin in Artemisia spp. including material used in retracted clinical trials
2022, Journal of Pharmaceutical and Biomedical AnalysisCitation Excerpt :Both trials reported outcomes far better than expected, for example; the authors stated that; “A. annua and A. afra infusions are polytherapies with better outcomes than ASAQ [artesunate amodiaquine] against malaria.” Both trials were however retracted [5,6], following concerns that were raised by several researchers [7–9]. One of the many points of critique was that the authors reported a significant level of artemisinin in the A. afra material, and as such, would have been the first to report on the presence of artemisinin in A. afra.