Études in vitro

Artemisia afra Jacq.

1992

Graven E.H., Deans S.G., Svoboda K.P., Mavi S. & Gundiza M.G.
Antimicrobial and Antioxydative Properties of the volatice Essential Oil of Artemisia afra Jack
Flavour and Fragrance Journal, 7, 121-123 (1992)

Full text submitted to request

Abstract :

Steam-distilled volatile oil from Artemisia afra Jacq. (family Compositae), indigenous to the mountainous regions in southern Africa and used in popular medicine, was analysed by gas chromatography and tested for antimicrobial and antioxidative properties. The main components of the volatile oil were α- and β- thujone (52 %), 1,8-cineole (13%), camphor (15%) and α-pinene (2%). Twenty-five bacterial species and three filamentous fungi were used to assess the antimicrobial properties. Fifteen test bacteria and one fungus showed high degree of inhibition of growth caused by the volatile oil. The most susceptible organisms were Acinetobacter calcoaceticus, Beneckea natriegens, Brevibacterium linens, Brochothrix thermosphacta, Citrobacter freundii, Klebsiella pneumoniae and Serralid marcescens. The oil exerted considerable antioxidative effect.

Key words : Essential oil Artemsia afra Jacq. Compositae GC analysis Antimicrobial activity Antioxidative properties

1996

Meryl A. Abrahams
Bioassay-guided fractionation of Artemisia afra for in vitro antimalarial activity against Plasmodium falciparum.
Master of Science (Medicine) December 1996, A project submitted to the Department of Pharmacology, University of Cape Town in fulfillment of the requirements for the degree

Bioassay-guided fractionation of Artemisia afra for in vitro antimalarial activity against Plasmodium. falciparum

Abstract :

With the increase in recent years in the prevalence of malaria, and in drug resistance of Plasmodium. falciparum, there has been much interest in natural plant products for new antimalarials with novel modes of action against Plasmodium. Artemisinin or Qinghaosu is one such antimalarial isolated from a Chinese herb, Artemisia annua (Asteraceae) and it is currently undergoing phase I and II clinical trials. The Southern African species, Artemisia afra (African wormwood, wildeals, lengana) is commonly used by local traditional healers for symptoms of malaria, in particular fever. Thus it seemed appropriate to investigate this species for antimalarial activity.
Crude petroleum ether soxhlet extracts of Artemisia afra had demonstrated antimalarial activity against Plasmodium. falciparum, FCR-3, cultured in vitro. The IC50 values ranged from 5-13μg/ml. The extract from leaves and flowers was then screened against D10 (chloroquine-sensitive) and FAC8 (chloroquine-resistant) Plasmodium falciparum, in vino, with IC50 values of 1.03 μg/ml and 1.5 μg/ml respectively. This extract was fractionated by column chromatography using silica gel-60 and the fractions obtained were screened for antimalarial activity. The most active fraction had an IC50 of 0.5μg/ml against D10 and FAC8. Using TLC and HPLC-UV analysis with pure artemisinin as a standard, no artemisinin could be detected in this fraction. This result was confirmed by thermospray LC-MS analyses. Purification of this fraction yielded ultimately a single pure compound ; a clear colourless oil identified by MS and NMR analyses as hydroxydavanone. The compound was screened against a variety of Plasmodium falciparum strains with varying degrees of sensitivity and resistance to both chloroquine and mefloquine. Their sensitivity against artemisinin was also established. [C50 values obtained for the isolated pure compound against P. fulcipurum ranged from 0.87 to 2.54μg/ml. The [C50 values obtained for general cytotoxicity of the crude extract and isolated pure compound against RAT-1 fibroblast cells were 34.78 + 8.23 and 6.29 + 0.95 μg/ml (n=4) respectively. Thus the crude extract and isolated pure compound exhibited a greater antimalarial than cytotoxic effect. Hence, there are implications for Artemisia afra to be used as a phytomedicine for the treatment of malaria. In vivo studies are recommended for hydroxydavanone in order to fully assess its potential for clinical use.

1998

Moges Kassa, Robert Mshana, Azeb Regassa and Getachew Assefa
In vitro test of five Ethiopian medicinal plants for antimalarial activity against Plasmodium falciparum.
Ethiopian Journal of Science, 21(1):81_89, 1998

In vitro test of five Ethiopian medicinal plants for antimalarial activity against Plasmodium falciparum

Abstract :

The in vitro antimalarial activity of crude extracts from aerial parts of Ajuga remota Benth., Artemisia afra Jacq. and Artemisia rehan Chiov., seeds of Lepidium sativum (L.) and roots of Securidaca longipedunculata Fresen. were studied by utilizing the inhibition of uptake of [3H]hypoxanthine into Plasmodium. falciparum line FCA-2/Ethiopia. Of the five extracts tested, extracts from seeds of Lepidium sativum and Securidaca longipedunculata showed no antimalarial activity at the highest concentration [50 μg(ml)-1] used in the present study. However, ethanol extracts from aerial parts of Artemisia afra, Artemisia rehan and Ajuga remota possessed antimalarial activity with IC50 values of the order of 7-23 μg(ml)-1. Artemisia afra showed the highest activity [IC50=μg(ml)-1] as compared to that of Artemisia rehan [IC50=,14 μg(ml)-1] and Ajuga remota [IC50=23 μg(ml)-1]. Results of this study showed that the extracts from three of the plants did have antimalarial activity, which suggests further investigations of cytotoxicity, chemical isolation and in viva studies of those plants with potential antimalarials.

Key words : Crude extracts, in vitro, Plasmodium. falciparum

1999

T. Mangena and N.Y.O. Muyima
Comparative evaluation of the antimicrobial activities of essential oils of Artemisia afra, Pteronia incana and Rosmarinus officinalis on selected bacteria and yeast strains
Letters in Applied Microbiology 1999, 28, 291–296

Comparative evaluation of the antimicrobial activities of essential oils of {Artemisia afra}, Pteronia incana and Rosmarinus officinalis on selected bacteria and yeast strains

Abstract :

Essential oils are frequently used for flavour and fragrance in the perfume, pharmaceutical, cosmetic and food industries. The antimicrobial activities of the essential oils of Artemisia afra, Pteronia incana and Rosmarinus officinalis were tested against 41 microbial strains. The test organisms were selected on the basis of their significance as food spoilage and/or poisoning, common human and plant pathogens. The agar diffusion assay was performed using nutrient agar and antibiotic medium. All the oils tested displayed some antimicrobial activities. However, the efficiency differed and depended both on the type and concentration of the oil, as well as the test microbial strain. Artemisia afra and Rosmarinus officinalis showed similar and higher antimicrobial activity than Pteronia incana. Due to their broad antimicrobial activities, the essential oils of the above plants growing in Eastern Cape may have preservative potential for the food and cosmetic industries.

2004

Cailean Clarkson, Vinesh J. Maharaj, Neil R. Crouch, Olwen M. Grace, Pamisha Pillay, Motlalepula G. Matsabisa, Niresh Bhagwandin, Peter J. Smith, Peter I. Folb
In vitro antiplasmodial activity of medicinal plants native to or naturalised in South Africa
Journal of Ethnopharmacology 92 (2004) 177–191

In vitro antiplasmodial activity of medicinal plants native to or naturalised in South Africa

Abstract :

The increasing prevalence and distribution of malaria has been attributed to a number of factors, one of them being the emergence and spread of drug resistant parasites. Efforts are now being directed towards the discovery and development of new chemically diverse antimalarial agents. The present study reports on the in vitro antiplasmodial activity of 134 plant taxa native to or naturalised in South Africa, representing 54 families, which were selected semi-quantitatively using weighted criteria. The plant extracts were tested for in vitro activity against a Plasmodium. falciparum strain D10 using the parasite lactate dehydrogenase (pLDH) assay. Of the 134 species assayed, 49% showed promising antiplasmodial activity (IC50 ≤ 10μg/ml ), while 17% were found to be highly active (IC50 ≤ 5μg/ml). Several plant species and genera were shown for the first time to possess in vitro antiplasmodial activity. These results support a rational rather than random approach to the selection of antiplasmodial screening candidates, and identify a number of promising taxa for further investigation as plant-based antimalarial agents.
Keywords : Malaria ; Antiplasmodial ; Plasmodium. falciparum ; Ethnomedicinal plants ; South Africa

2007

James W. Gathirwa, Waweru Jeremiah
In vitro anti-plasmodial and in vivo anti-malarial activity of some medicinal plants used by the Meru community in Kenya for treatment of malaria
A thesis submitted in partial fulfillment of the requirements of the award of the degree of Master of Science (Biotechnology) of Kenyatta University

Full text submitted to request

Malaria is a serious disease affecting approximately 500 million people worldwide resulting in 3 million deaths every year. Increasing resistance to the commonly used anti-malarial drugs has impacted negatively to its treatment. Consequently, there is an urgent need to develop new drugs. Plants have been considered to be a possible alternative and a rich source of new drugs. Most traditional healers in Africa use medicinal plants in combination and not singly. Research to justify use of medicinal plants in treatment of malaria alone and in combination is a priority. The objective of this study was to investigate the efficacy and safety of traditional anti-malarial plant extracts individually and in combination. Aqueous and methanol extracts of 15 plants traditionally used for treatment of malaria in Meru District, Kenya were tested in vitro and in vivo against Plasmodium. falciparum (06 and W2 clones) and P. berghei. Toxicity of the active extracts was evaluated in vitro and in vivo, while their interactions in combination were tested by the sum-FIC method. Of the plants tested in vitro, 25.0% were highly active (IC50 <10 μg/ml), 45.59% moderately active (IC50 10-50 <μg/ml), 16.18% had weak activity of 50-100 μg/ml while 13.24% were not active IC50 >100 μg/ml. Both the water and methanol extracts of Boscia salicifolia Olivo and Artemisia afra Jacq. ex Willd. Were the most active against both the chloroquine (CQ) sensitive (D6) and the CQ resistant (W2) Plasmodium falciparum clones. When tested in vivo in a mouse model, A. afra and Rhus natalensis Bernh. ex Krauss. depicted the highest percent parasite clearance and a chemossupresion greater than 70%. Evaluating effect of combining some of these extracts with one another or with CQ against the multi-drug resistant Plasmodium falciparum clone W2 revealed some synergistic effect. Marked synergy/additive effect was among blends of plant extracts as opposed to blends with CQ that in many cases was antagonistic. The highest synergy was between Sclerocarya birrea (A.Rich.) Hochst + Lannea schweinfurthii (Engl.) Engl., A. afra + Clausena anisata (Willd.) Hook. f. ex. Benth., A. afra + L. sweinfurthii, and A. afra + Clutia robusta Pax, E, FZ. The interaction between Tabernae montana holstii K. Schum + chloroquine was largely additive. Impressive cytotoxicity results were obtained with most of the plants tested revealing high selectivity indices an indication of enabling achievement of therapeutic doses at safe concentrations. In vivo acute toxicity on these medicinal plants revealed that most were not toxic at a high dose of 5000 mg/kg body weight. The plants with low IC50 values, high percent chemossupresion and low toxicity profiles are potential sources for novel antiplasmodial agents. These findings also justify use of combined medicinal plants in traditional medicine practices.

***

James W. Gathirwa, Geoffrey M. Rukunga, Eliud N. M. Njagi, Sabah A. Omar, Anastasia N. Guantai, Charles N. Muthaura, Peter G. Mwitari, Cecilia W. Kimani, Peter G. Kirira, Festus M. Tolo, Teresia N. Ndunda, Isaiah O. Ndiege
In vitro anti-plasmodial and in vivo anti-malarial activity of some plants traditionally used for the treatment of malaria by the Meru community in Kenya
Journal of Natural Medicine (2007) 61:261–268

In vitro anti-plasmodial and in vivo anti-malarial activity of some plants traditionally used for the treatment of malaria by the Meru community in Kenya

Abstract :

Extracts of seven medicinal plant species used for treatment of malaria in traditional/cultural health systems of the Ameru people in Kenya were tested in vitro and in vivo against Plasmodium. falciparum (D6 and W2 strains) and P. berghei, respectively. Of the plants tested, 28.57% were highly active (IC50 <10 μg/ml) and 42.86% moderately active (IC50 10–50 μg/ml), while 28.57% had weak activity of 50–125 μg/ml in vitro. The water and methanol extracts of Boscia salicifolia Oliv. and Artemisia afra Jacq. (ex-Willd.) were the most active against both the chloroquine (CQ)-sensitive (D6) and the CQ-resistant (W2) Plasmodium falciparum strains. Artemisia afra and Rhus natalensis Bernh. (ex-Krauss) exhibited the highest parasite clearance and chemo-suppression (>70%) in vivo (in mice). The plants with high in vitro anti-plasmodial (low values) and high anti-malarial activity (high chemo-suppression) in vivo are potential sources of novel anti-malarial drugs.
Keywords : Anti-malarial ; Anti-plasmodial ; Toxicity ; Boscia salicifolia ; Artemisia afra ; Rhus natalensis

***

Sammy Tsietsi Seatlholo
The biological activity of specific essential oil constituents
A dissertation submitted to the Faculty of Health Sciences, University of the Witwatersrand, in fulfilment of the requirements for the degree of Master of Science in Medicine Johannesburg, South Africa, 2007

The biological activity of specific essential oil constituents

Abstract :

Twenty essential oil constituents (EOC’s) from seven structural groups were tested for their antimalarial, antimicrobial (both bacterial and fungal), anti-oxidant, anticholinesterase and toxicity properties. To test for their antimalarial property, the tritiated hypoxanthine incorporation assay was used, while the disc diffusion and minimum inhibitory concentration (MIC) microplate assays were employed for the antimicrobial properties. The 2,2-diphenyl-l-picrylhydrazyl (DPPH) method was used to test the anti-oxidant property and their toxicity profile was assessed with the 3-(4,5-dimethyl-2-thiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) cellular viability assay. The anticholinesterase activity was determined using the thin layer chromatography (TLC) bioautographic method. The EOC’s were found to inhibit the growth of Plasmodium falciparum with IC50 values ranging between 0.9 to 1528.8 μM with E- and Z-(+)-nerolidol, (-)-pulegone, (+)-α-pinene and linalyl acetate being the most active. In combination p-cymene (the least active) and E- and Z-(i)-nerolidol (the most active) displayed the most synergistic interaction (ΣFIC = 0.09), with their antimalarial activity comparable to that of the interaction between E- and Z-(+)-nerolidol and quinine (ΣFIC = 0.01). Eugenol had the most favourable safety index and was the only EOC with anti-oxidant activity comparable to vitamin C. Combination studies showed that E- and Z-(+)-nerolidol and (-)-pulegone or quinine, p-cymene and γ-terpinene or (-)-pulegone potentiated each other’s toxicity. The EOC’s inhibited the growth of Gram-positive, Grain-negative bacteria and yeast with MIC values ranging from 1.66 to >238.4mM. When combined, synergism was observed between (+)-β-pinene and caryacrol or y-terpinene ; γ-terpinene and geranyl acetate when tested against Staphylococcus aureus, while (+)-[5-pinene and (-)-menthone showed antagonism against Candida albicans. The combinations of EOC’s and a standard antimicrobial resulted in synergistic interactions between caryacrol and ciprofloxacin against Bacillus cereus, eugenol and ciprofloxacin against Eschericia coli, caryacrol and amphotericin B against Candida albicans. The trans-geraniol and E- and Z-(i)-nerolidol combination demonstrated an additive interaction against Bacillus cereus, while for eugenol and E- and Z-(i)-nerolidol an indifferent interaction against Eschericia coli was noted. These results show that the biological activities of EOC’s can vary when used alone and in combination. They do have the potential to be used as templates for novel drugs and as adjuncts to modern medicines in the combat against drug resistance.

2010

Ning Qing Liua, Martine Cao, Michel Frédérich, Young Hae Choi, Robert Verpoorte,
Frank van der Kooy
Metabolomic investigation of the ethnopharmacological use of Artemisia afra with NMR spectroscopy and multivariate data analysis
Journal of Ethnopharmacology 128 (2010) 230–235

Full text submitted to request

Abstract :

Ethnopharmacological relevance : Artemisia afra has been used as an infusion to treat malaria throughout the southern parts of Africa, in much the same way as the antimalarial plant Artemisia annua in China. The antiplasmodial activity of purified components from an apolar fraction of Artemisia afra has been shown in the past. No data on the efficacy of the tea infusion prepared from Artemisia afra are however available.

Objective : To investigate the antiplasmodial activity of various extracts of Artemisia afra including an ethnopharmacological prepared sample. To identify polar metabolites in Artemisia afra and Artemisia annua and by using multivariate data analysis investigate the metabolic differences between these species.

Materials and Methods : The antiplasmodial activity of Artemisia afra and Artemisia annua extracts were tested for activity against Plasmodium falciparum 3D7 (chloroquine-sensitive strain) with chloroquine, quinine and artemisinin as positive controls. Hydrophilic metabolites in Artemisia afra and Artemisia annua were identified directly from the crude extracts through 1D- and2D-NMRspectra. The NMR spectra were also used to differentiate between the two species using principal component analysis (PCA) for quality control purposes.

Results : The apolar fractions of both Artemisia afra and Artemisia annua showed activity against Plasmodium falciparum while activity was only found in the tea infusion of Artemisia annua. Metabolomic studies using 1D- and 2D-NMR spectroscopy identified 24 semi-polar components in Artemisia afra including three new phenylpropanoids for this species : caffeic acid, chlorogenic acid and 3,5-dicaffeoyl quinic acid. PCA analysis conducted on the samples yielded good separation between the polar extracts of Artemisia afra and Artemisia annua.
Conclusion : These findings shows that there are no in vitro activity in the tea infusion of Artemisia afra and lists the identified metabolites causing the metabolic differences between Artemisia afra and Artemisia annua for quality control purposes.

Keywords : Antiplasmodial activity, Artemisia afra, NMR spectroscopy, Multivariate data analysis, Plasmodium. falciparum

***

Yusra Kriel
The immune-modulating activity of Artemisia afra
Submitted in fulfilment of the requirement for the degree, Magister Scientiae (M.Sc) at the University of The Western Cape, South Africa Supervised by Professor Edmund J. Pool, May 2010

The immune-modulating activity of Artemisia afra

Abstract

The human immune system consists of innate and adaptive mechanisms of defence that protect the host from harmful substances. Cytokines and other immune components play an important role in the induction and regulation of these defence mechanisms. Despite these mechanisms, sometimes pathogens still manage to evade the immune system causing disease ; or allergens result in hypersensitive reactions ; or the immune system becomes overly sensitive and starts attacking the “self”. Irrespective of the cause, despite its best efforts, the immune system sometimes needs help regulating its defences.

Artemisia afra is an indigenous member of the daisy or Asteraceae family. It is one of the oldest and most common plants used as a traditional medicine in South Africa. Because of the great diversity of ailments traditionally treated with Artemisia afra, it is considered a “cure-all”. The aerial parts contain various phenolic compounds that have anti-bacterial and anti-fungal activity. This helps to explain its popularity in treating bacterial infections such as sore throats, ear infections and various bronchial diseases. Other traditional uses include viral infections such as measles and influenza, and parasitic infections such as malaria and intestinal parasites. Non-pathogenic conditions traditionally treated with Artemisia afra include diabetes mellitus, gout and neuraligia, autoimmune conditions like rheumatoid arthritis and allergic conditions such as asthma. Due to this wide range of traditional
indications, Artemisia afra is thought to have immune regulating effects.

Herbal medications are becoming increasingly popular with the general public. Knowledge regarding indigenous medicines is very limited, while the need for such knowledge is becoming more essential. It is estimated that in Africa approximately 80 % of people rely on herbal medicine for primary health care. Most literature sources focus on the study of European herbs and medical practitioners are not well equipped to guide the public on issues relating to herbal medicines. Adverse and side effects of herbs become common when the herb is taken incorrectly or together with certain medications. Despite the wide variety of conditions traditionally treated with Artemisia afra, limited literature exists regarding the bioactivities on the species, and no immune studies have been done until now. The aim of this study was to use human whole blood cultures to examine Artemisia afra’s immunomodulating effects in vitro.

20 % (w/v) Artemisia afra extract was prepared using 94.4 % ethanol and milled aerial herb organs. The extract was air dried and re-suspended in DMSO to obtain a 50 % (wet leaf w/v) extract. Blood was collected from healthy male volunteers and diluted with RPMI1640. To measure inflammatory activity and cytotoxicity, stimulated blood contained 1 volume of 10 μg/ml LPS in DMSO, 10 volumes of blood and 89 volumes of RMPI-1640.

Blood (200 μl/well) was added to various concentrations of Artemisia afra. This was
incubated at 37 ºC for 24 hours. For cell-mediated and humoral immunity, stimulated blood contained 10 volumes of blood and 89 volumes of RPMI-1640 medium and 1 volume of 1.6 mg/ml PHA in RPMI-1640 and incubated for 48 hours. An LDH assay was used to analyse the herb for cytotoxicity and various ELISAs for cytokine analysis. IL-6 was used as a biomarker for inflammatory activity, IL-10 for humoral immunity and IFN-γ for cellmediated immunity. Results were statistically analysed using ANOVA tests.

Results showed that Artemisia afra was significantly cytotoxic (P<0.050)>

Abstract

Background : Many of the plants used to treat certain diseases, because they have showed antimicrobial activity. In this case, many studies have conducted on antimicrobial and antioxidant activity of Artemisia annua.

Materials and Methods : The purpose of this study is to determine the antibacterial effects of aqueous, chloroform, methanol and ethanol extracts of Artemisia annua against eight bacterial species. Antimicrobial activity, minimum inhibitory concentration and minimum bactericidal activity of the essential oil and extract was performed by agar disc diffusion and microdilution broth methods.

Results : The obtained results showed antibacterial activity of the organic and chloroformic extracts of Artemisia annua against the tested microorganisms. Presence of tannins, saponins, alkaloids, amino acids, phenolic compounds, quinines and terpenoids were identified in the composition of the obtained extract using mass gas-chromatograph. The best result for the minimum inhibitory Concentration and minimum bactericidal concentration was reported for the 32 mg/ml of chloroformic extract.

Conclusion : The results indicate the fact that the extracts and essential oils of the plants can be useful as medicinal or preservatives composition.
Keywords : Artemisia annua, Plant extract, Anti-bacterial, Minimum inhibitory, Concentration

***

Garland More, Namrita Lall, Ahmed Hussein, and Thilivhali Emmanuel Tshikalange
Antimicrobial Constituents of Artemisia afra Jacq. Ex Willd. against Periodontal Pathogens
Evidence-Based Complementary and Alternative Medicine, Volume 2012, Article ID 252758

Antimicrobial Constituents of Artemisia afra Jacq. Ex Willd. against Periodontal Pathogens Evidence-Based

Abstract :

The phytochemical investigation of an ethanol extract of Artemisia afra led to the isolation of six known compounds, acacetin (1), 12α,4α-dihydroxybishopsolicepolide (2), scopoletin (3), α-amyrin (4), phytol (5), and a pentacyclic triterpenoid betulinic acid (6). The compounds were evaluated for antimicrobial activity against Gram positive (Actinomyces naeslundii, Actinomyces israelii, and Streptococcus mutans), Gram negative bacteria (Prevotella intermedia, Porphyromonas gingivalis and Aggregatibacter actinomycetemcomitans previously known as Actinobacillus actinomycetemcomitans), and Candida albicans. The crude extract of A. afra inhibited the growth of all tested microbial species at concentration range of 1.6mg/mL to 25 mg/mL. The compounds 1–6 also showed activity range at 1.0 mg/mL to 0.25mg/mL. Three best compounds (scopoletin, betulinic acid, and acacetin) which showed good antimicrobial activity were selected for further studies. Cytotoxicity of extract and compounds was determined using the XTT cell proliferation kit. The antioxidant activity of the extract and compounds was done using the DPPH scavenging method. The extract showed good antioxidant activity with a value of 22.2 μg/mL. Scopoletin had a strong transformation of the DPPH radical into its reduced form, with an IC50 value of 1.24 μg/mL which was significant to that of vitamin C (1.22 μg/mL). Acacetin and betulinic acid exhibited a decreased scavenging activity with the IC50 of 2.39 and 2.42 μg/mL, respectively. The extract and compounds showed moderate toxicity on McCoy fibroblast cell line and scopoletin was relatively nontoxic with an IC50 value of 132.5 μg/mL. Acacetin and betulinic acid also showed a smooth trend of non-toxic effects with IC50 values of 35.44 and 30.96 μg/mL. The obtained results in this study confirm the use of A. afra in the treatment of microbial infections.

***

Andrea Lubbe, Isabell Seiber, Thomas Klimkait, Frank van der Kooy
Ethnopharmacology in overdrive : The remarkable anti-HIV activity of Artemisia annua
Journal of Ethnopharmacology, 2012 June 14 ; 141 (3) : 854-9.

Full text submitted to request

Abstract :

Ethnopharmacological relevance : Artemisia annua contains the well-known antimalarial compound artemisinin, which forms the backbone of the global malaria treatment regime. In African countries a tea infusion prepared from Artemisia annua has been used for the treatment of malaria only for the past 10-20 years. Several informal claims in Africa exist that the Artemisia annua tea infusions are also able to inhibit HIV. Since HIV is a relatively newly emerged disease, the claims, if substantiated, could provide a very good example of "ethnopharmacology in overdrive". The objective of this study was to provide quantitative scientific evidence that the Artemisia annua tea infusion exhibits anti-HIV activity through in vitro studies. A second objective was to determine if artemisinin plays a direct or indirect (synergistic) role in any observed activity. This was done by the inclusion of a chemically closely related species, Artemisia afra, known not to contain any artemisinin in our studies.

Materials and methods : Validated cellular systems were used to test Artemisia annua tea samples for anti-HIV activity. Two independent tests with different formats (an infection format and a co-cultivation format) were used. Samples were also tested for cellular toxicity against the human cells used in the assays.
Results : The Artemisia annua tea infusion was found to be highly active with IC(50) values as low as 2.0 μg/mL. Moreover we found that artemisinin was inactive at 25 μg/mL and that a chemically related species Artemisia afra (not containing artemisinin) showed a similar level of activity. This indicates that the role of artemisinin, directly or indirectly (synergism), in the observed activity is rather limited. Additionally, no cellular toxicity was seen for the tea infusion at the highest concentrations tested.

Conclusion : This study provides the first in vitro evidence of anti-HIV activity of the Artemisia annua tea infusion. We also report for the first time on the anti-HIV activity of Artemisia afra although this was not an objective of this study. These results open the way to identify new active pharmaceutical ingredients in Artemisia annua and thereby potentially reduce the cost for the production of the important antimalarial compound artemisinin.

2013

L. Spies, T.C. Koekemoer, A.A. Sowemimo, E.D. Goosen, M. Van de Venter
Caspase-dependent apoptosis is induced by Artemisia afra Jacq. ex Willd in a mitochondria-dependent manner after G2/M arrest
South African Journal of Botany, Volume 84, 2013, pp. 104-109

Caspase-dependent apoptosis is induced by Artemisia afra Jacq. ex Willd in a mitochondria-dependent manner after G2/M arrest

Abstract

Artemisia afra is one of the oldest, most well known and widely used traditional medicinal plants in South Africa. It is used to treat many different medical conditions, particularly respiratory and inflammatory ailments (Liu et al., 2009). There is no reported evidence of its use for the treatment of cancer but due to its reported cytotoxicity (Fouche et al., 2008 ; Mativandlela et al., 2008), we investigated the mode of cell death induced by an ethanolic A. afra extract by using two cancer cell lines. IC50 values of 18.21 and 31.88 μg/mL of ethanol extracts were determined against U937 and HeLa cancer cells, respectively. An IC50 value of the aqueous extract was greater than 250 μg/mL. The effect of the cytotoxic ethanolic A. afra extract on U937 and HeLa cells and their progression through the cell cycle, apoptosis and mitochondrial membrane potential were investigated. Melphalan was used as a positive control. After 12 h of treatment with A. afra a delay in G2/M phase of the cell cycle was evident. Apoptosis was confirmed by using the TUNEL assay for DNA fragmentation, as well as fluorescent staining with annexin V-FITC. Apoptosis was evident with the positive control and A. afra treatment at 24 and 48 h. JC-1 staining showed a decrease in mitochondrial membrane potential at 24 h. The results obtained suggest that Artemisia afra potentially has medicinal anticancer properties

Keywords : Artemisia afra, Cytotoxicity, Apoptosis, HeLa, U937

2016

P. Moyo, M.E. Botha, S. Nondaba, J. Niemand, V.J. Maharaj, J.N. Eloff, A.I. Louw, L. Birkholtz
In vitro inhibition of Plasmodium. falciparum early and late stage gametocyte viability by extracts from eight traditionally used South African plant species
Journal of Ethnopharmacology, 2016

In vitro inhibition of Plasmodium. falciparum early and late stage gametocyte viability by extracts from eight traditionally used South African plant species

Abstract :

Ethnopharmacological relevance : Extracts of plant species, used traditionally to treat malaria, have been extensively investigated for their activity against Plasmodium intraerythrocytic asexual parasites in search of new antimalarial drugs. However, less effort has been directed towards examining their efficacy in blocking transmission. Here, we report the results of the in vitro screening of extracts from eight selected plant species used traditionally to treat malaria in South Africa for activity against Plasmodium falciparum NF54 early and late stage gametocytes. The species used were Khaya anthotheca, Trichilia emetica, Turraea floribunda, Leonotis leonurus, Leonotis leonurus ex Hort, Olea europaea subsp. Africana, Catha edulis and Artemisia afra.
Aim of the Study : To investigate the activities of extracts from plant species traditionally used for malaria treatment against Plasmodium falciparum gametocytes.

Material and Methods : Air-dried and ground plant leaves were extracted using acetone. Primary two point in vitro phenotypic screens against both early and late stage gametocytes were done at 10 and 20 μg/ml followed by full IC50 determination of the most active extracts. Inhibition of gametocyte viability in vitro was assessed using the parasite lactate dehydrogenase (pLDH) assay.

Results : Of the eight crude acetone extracts from plant species screened in vitro, four had good activity with over 50-70% inhibition of early and late stage gametocytes’ viability at 10 and 20 μg/ml, respectively. Artemisia afra (Asteraceae), Trichilia emetica (Meliaceae) and Turraea floribunda (Meliaceae) were additionally highly active against both gametocyte stages with IC50 values of less than 10 μg/ml while Leonotis leonurus ex Hort (Lamiaceae) was moderately active (IC50<20 μg/ml). The activity of these three highly active plant species was significantly more pronounced on late stage gametocytes compared to early stages.

Conclusion : This study shows the potential transmission blocking activity of extracts from selected South African medicinal plants and substantiates their traditional use in malaria control that broadly encompasses prevention, treatment and transmission.

2019

Phanankosi Moyo, Phaladi Kunyane, Mamoalosi A. Selepe, Jacobus N. Eloff, Jandeli Niemand, Abraham I. Louw, Vinesh J. Maharaj and Lyn‑Marie Birkholtz
Bioassay-guided isolation and identification of gametocytocidal compounds from Artemisia afra (Asteraceae)
Malaria Journal 18, Article number : 65 (2019)

Bioassay-guided isolation and identification of gametocytocidal compounds from Artemisia afra (Asteraceae)

Abstract :

Background : Optimal adoption of the malaria transmission-blocking strategy is currently limited by lack of safe and efficacious drugs. This has sparked the exploration of different sources of drugs in search of transmission-blocking agents. While plant species have been extensively investigated in search of malaria chemotherapeutic agents, comparatively less effort has been channelled towards exploring them in search of transmission-blocking drugs. Artemisia afra (Asteraceae), a prominent feature of South African folk medicine, is used for the treatment of a number of diseases, including malaria. In search of transmission-blocking compounds aimed against Plasmodium parasites, the current study endeavoured to isolate and identify gametocytocidal compounds from Artemisia afra.

Methods : A bioassay-guided isolation approach was adopted wherein a combination of solvent–solvent partitioning and gravity column chromatography was used. Collected fractions were continuously screened in vitro for their ability to inhibit the viability of primarily late-stage gametocytes of Plasmodium. falciparum (NF54 strain), using a parasite lactate dehydrogenase assay. Chemical structures of isolated compounds were elucidated using UPLC-MS/MS and NMR data analysis.

Results : Two guaianolide sesquiterpene lactones, 1α,4α-dihydroxybishopsolicepolide and yomogiartemin, were isolated and shown to be active (IC50 < 10 μg/ml ; 10 μM) against both gametocytes and intra-erythrocytic asexual Plasmodium falciparum parasites. Interestingly, 1α,4α-dihydroxybishopsolicepolide was significantly more potent against late-stage gametocytes than to early-stage gametocytes and intra-erythrocytic asexual Plasmodium falciparum parasites. Additionally, both isolated compounds were not overly cytotoxic against HepG2 cells in vitro.

Conclusion : This study provides the first instance of isolated compounds from Artemisia afra against Plasmodium falciparum gametocytes as a starting point for further investigations on more plant species in search of transmission-blocking compounds.
Keywords : Malaria, Gametocytes, Transmission-blocking, Artemisia afra, Sesquiterpene lactone, Natural products, Plasmodium. falciparum

***

N.F. Kane, M.C. Kyama, J.K. Nganga, A. Hassanali, M. Diallo, F.T. Kimani
Comparison of phytochemical profiles and antimalarial activities of Artemisia afra plant collected from five countries in Africa
South African Journal of Botany 125 (2019) 126–133

Full text submitted to request

Abstract :

Malaria is one of the most dangerous and deadly tropical disease in Africa affecting millions of individuals yearly. It is a major global public health problem, with an alarming spread of parasite resistance to the ACTs drugs. This situation explain the urge to discover new antimalarial compounds. Indigenous species to Africa and traditionally used for years by traditional healers, Artemisia afra is a big source for new antimalarial drugs. Aerial parts of Artemisia afra plant collected from South Africa, Kenya, Tanzania, Burundi and Senegal were each extracted with solvents of different polarity (hexane, dichloromethane, ethanol, andwater), and the different extracts were then screened and compared for their antimalarial activities against two Plasmodium. falciparum strains W2 (CQ resistant) and D6 (CQ sensitive) ; and also compared for their total phenols, flavonoids content and antioxidant activities. Phytochemical screening of the extracts revealed the presence of terpenoids, alkaloids, tannins, saponins and cardiac glycosides. Ethanolic extract of Artemisia afra collected from Burundi was found to have the highest concentration of phenols (606.9449 mg GAE/g of extract) and flavonoids (242.4745 mg Rutin/g of extract) and also exhibited the highest antioxidant activity (IC50=3.12 μg/mL) compare to the others. Total phenols and total flavonoids were found to correlate with the antioxidant activity. Artemisia afra collected from Burundi also showed the highest antimalarial activity compare to the other extracts, the hexane extract of Artemisia afra from Burundi have the highest (IC50 = 0.71μ g/ml for W2 and IC50 = 3.18 μg/ml for D6) ; following by the ethanolic extract (IC50 = 2.66 μg/ml for W2 and 7.84 μg/ml for D6 ; then the dichloromethane extract (IC50 = 3.04 μg/ml for W2 and IC50= 7.92 μg/ml for D6). Comparison of the five Artemisia afra plants collected from South Africa, Kenya, Tanzania, Burundi and Senegal showed that the extracts from Burundi had the highest total content of phenols and flavonoids and also the highest level of antimalarial activity compared to the other plant extracts.
Keywords : Plasmodium. falciparum, Antimalarial activity, Artemisia afra, Phytochemicals screening, Antioxidant activity, Malaria

2019

Ndeye Fatou Kane
Effect of extracts of Artemisia afra collected from five different regions in Africa (Kenya, Burundi, Tanzania, South Africa and Senegal) on in vitro and in vivo cultures of Plasmodium Species
A thesis submitted to Pan African University Institute of Science, Technology and Innovation in partial fulfillment of the requirement for the award of the degree of Doctor of Philosophy in Molecular Biology and Biotechnology of the Pan African University 2019

Full text submitted to request

Abstract :
Malaria is one of the deadliest disease in the world affecting millions of individuals yearly. Artemisinin combination therapies (ACTs), which are the first line of defense against this disease for many years, show some inefficacy due to delay in parasite clearance. Many episodes of resistance against these drugs have been registered in many countries in Africa and in Asia. Currently, there is growing research interest in the use of full blend extract of medicinal plants like Artemisia afra or Artemisia annua as an alternative treatment. Artemisia afra is an indigenous species to Africa, and are traditionally used for decades by traditional healers to cure a lot of afflictions among them malaria. The main objective of this thesis is to compare the growth inhibition effects and molecular profiles of the parasite exposed to extracts of the Artemisia afra plants collected from five regions. Artemisia afra leaves were collected from five countries in Africa (South Africa, Tanzania, Burundi, Senegal, and Kenya), and compared for their level of phytochemicals content, antimalarial, and antioxidant activities. The plant extracts were first tested in vitro and the most active extracts were incubated during 2 days with the parasites to study the expression level of FabI and FabZ. A virtual screening was ran using PyRx with vina to determine the potential interactions between the Fab enzymes (FabI and FabZ) and the active compounds of the plant extracts. The result showed a big antimalarial property of the plant, however a different level of activity depending on the geographical localization. Artemisia afra collected from Burundi was found to have the highest level of phenols and flavonoids. This plant also exhibited the highest antioxidant and antimalarial activities compared to the others. Acute toxicity test run in mice revealed an ED50 greater than 2500mg/kg body weight and no toxic sign was detected on the liver, the organs, and the tissues. The Fab I enzyme, which plays important rule during the liver stage of the malaria infection was found to be downregulated in the W2 strain, after exposition of the parasites with the ethanolic and dichloromethane of the plant extract collected from Burundi. In the D6 strain the enzyme was downregulated with the hexane and ethanolic extracts of the plant. Compared to Fab I, Fab Z was found to be downregulated only on the D6 strain when exposed to the hexane and ethanolic extracts, both extracts downregulate Fab I and Fab Z in the two strains (D6, W2). Virtual screening showed interaction between the active compounds of the plant and the Fab enzymes. In conclusion the results confirm the high antimalarial effect of Artemisia afra and also its prophylactic effect with the inhibition of Fab I enzyme which is crucial during liver stage of the Plasmodium. falciparum life cycle. The difference in level of flavonoids and phenols suggest that the agro-ecological zone play an important role in influencing the level of phytochemical. Artemisia afra active compounds detected during GCMS analysis was found to interact with the fab enzymes of the parasite, further study need to be done to confirm their in vitro activities of those active compounds.

Mis en ligne par La vie re-belle
 3/04/2020
 https://lavierebelle.org/artemisia-afra-etudes-in-vitro

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Études in vitro

Études in vitro de l’Artemisia afra

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