Dried-leaf Artemisia annua: A practical malaria therapeutic for developing countries?

Differential Anti-Fibrotic and Remodeling Responses of Human Dermal Fibroblasts to Artemisia sp., Artemisinin, and Its Derivatives

Fibrosis is a ubiquitous pathology, and prior studies have indicated that various artemisinin (ART) derivatives (including artesunate (AS), artemether (AM), and dihydroartemisinin (DHA)) can reduce fibrosis in vitro and in vivo. The medicinal plant Artemisia annua L. is the natural source of ART and is widely used, especially in underdeveloped countries, to treat a variety of diseases including malaria. A. afra contains no ART but is also antimalarial. Using human dermal fibroblasts (CRL-2097), we compared the effects of A. annua and A. afra tea infusions, ART, AS, AM, DHA, and a liver metabolite of ART, deoxyART (dART), on fibroblast viability and expression of key fibrotic marker genes after 1 and 4 days of treatment. AS, DHA, and Artemisia teas reduced fibroblast viability 4 d post-treatment in up to 80% of their respective controls. After 4 d of treatment, AS DHA and Artemisia teas downregulated ACTA2 up to 10 fold while ART had no significant effect, and AM increased viability by 10%. MMP1 and MMP3 were upregulated by AS, 17.5 and 32.6 fold, respectively, and by DHA, 8 and 51.8 fold, respectively. ART had no effect, but A. annua and A. afra teas increased MMP3 5 and 16-fold, respectively. Although A. afra tea increased COL3A1 5 fold, MMP1 decreased >7 fold with no change in either transcript by A. annua tea. Although A. annua contains ART, it had a significantly greater anti-fibrotic effect than ART alone but was less effective than A. afra. Immunofluorescent staining for smooth-muscle α-actin (α-SMA) correlated well with the transcriptional responses of drug-treated fibroblasts. Together, proliferation, qPCR, and immunofluorescence results show that treatment with ART, AS, DHA, and the two Artemisia teas yield differing responses, including those related to fibrosis, in human dermal fibroblasts, with evidence also of remodeling of fibrotic ECM.

Targeted screening of the synergistic components in Artemisia annua L. leading to enhanced antiplasmodial potency of artemisinin based on a "top down" PD-PK approach

ETHNOPHARMACOLOGICAL RELEVANCE

Artemisinin (ART) showed enhanced antimalarial potency in the herb Artemisia annua L. (A. annua), from which ART is isolated. Increased absorption of ART with inhibited metabolism in the plant matrix is an underlying mechanism. Several synergistic components have been reported based on a "bottom-up" approach, i.e., traditional isolation followed by pharmacokinetic and/or pharmacodynamic evaluation.

AIM OF THE STUDY

In this study, we employed a "top-down" approach based on in vivo antimalarial and pharmacokinetic studies to identify synergistic components in A. annua.

MATERIALS AND METHODS

Two A. annua extracts in different chemical composition were obtained by extraction using ethyl acetate (EA) and petroleum ether (PE). The synergistic antimalarial activity of ART in two extracts was compared both in vitro (Plasmodium falciparum) and in vivo (murine Plasmodium yoelii). For the PD-PK correlation analysis, the pharmacokinetic profiles of ART and its major metabolite (ART-M) were investigated in healthy rats after a single oral administration of pure ART (20 mg/kg) or equivalent ART in each A. annua extract. A liquid chromatography-tandem high-resolution mass spectrometry (LC-HRMS)-based analytical strategy was then applied for efficient component classification and structural characterization of the differential components in the targeted extract with a higher antimalarial potency. Major components isolated from the targeted extract were then evaluated for their synergistic effect in the same proportion.

RESULTS

Compared with pure ART (ED50, 5.6 mg/kg), ART showed enhanced antimalarial potency in two extracts in vivo (ED50 of EA, 2.9 mg/kg; ED50 of PE, 1.6 mg/kg), but not in vitro (IC50, 15.0-20.0 nM). A significant increase (1.7-fold) in ART absorption (AUC0-t) was found in rats after a single oral dose of equivalent ART in PE but not in EA; however, no significant change in the metabolic capability (AUCART-M/AUCART) was found for ART in either extract. The differential component analysis of the two extracts showed a higher composition of sesquiterpene compounds, especially component AB (3.0% in PE vs. 0.9% in EA) and component AA (14.1% in PE vs. 5.1% in EA). Two target sesquiterpenes were isolated and identified as arteannuin B (AB) and artemisinic acid (AA). The synergism between ART and AB/AA in the same proportion with PE extract (20:1.6:7.6, mg/kg) was verified by a pharmacokinetic study in rats.

CONCLUSIONS

A "top-down" strategy based on PD-PK studies was successfully employed to identify synergistic components for ART in A. annua. Two sesquiterpene compounds (arteannuin B and artemisinic acid) could enhance the antimalarial potency of ART by increasing its absorption.

Autofluorescent antimalarials by hybridization of artemisinin and coumarin: in vitro/in vivo studies and live-cell imaging

Malaria is one of our planet's most widespread and deadliest diseases, and there is an ever-consistent need for new and improved pharmaceuticals. Natural products have been an essential source of hit and lead compounds for drug discovery. Antimalarial drug artemisinin (ART), a highly effective natural product, is an enantiopure sesquiterpene lactone and occurs in Artemisia annua L. The development of improved antimalarial drugs, which are highly potent and at the same time inherently fluorescent is particularly favorable and highly desirable since they can be used for live-cell imaging, avoiding the requirement of the drug's linkage to an external fluorescent label. Herein, we present the first antimalarial autofluorescent artemisinin-coumarin hybrids with high fluorescence quantum yields of up to 0.94 and exhibiting excellent activity in vitro against CQ-resistant and multidrug-resistant P. falciparum strains (IC50 (Dd2) down to 0.5 nM; IC50 (K1) down to 0.3 nM) compared to reference drugs CQ (IC50 (Dd2) 165.3 nM; IC50 (K1) 302.8 nM) and artemisinin (IC50 (Dd2) 11.3 nM; IC50 (K1) 5.4 nM). Furthermore, a clear correlation between in vitro potency and in vivo efficacy of antimalarial autofluorescent hybrids was demonstrated. Moreover, deliberately designed autofluorescent artemisinin-coumarin hybrids, were not only able to overcome drug resistance, they were also of high value in investigating their mode of action via time-dependent imaging resolution in living P. falciparum-infected red blood cells.

Chemical Characterization of Different Extracts from Artemisia annua and Their Antioxidant, Enzyme Inhibitory and Anti-Inflammatory Properties

Artemisia annua L. (Asteraceae Family) is an important plant in Asia that has been used for treating different diseases, including fever due to malaria, wounds, tubercolisis, scabues, pain, convulsions, diabetes, and inflammation. In this study we aimed to evaluate the effects of different polarity extracts (hexane, dichloromethane, ethyl acetate, ethanol, ethanol/water (70 %) and water) from A. annua against the burden of inflammation and oxidative stress occurring in colon tissue exposed to LPS. In parallel, chemical composition, antiradical, and enzyme inhibition effects against α-amylase, α-glucosidase, tyrosinase, and cholinesterases were evaluated. The water extract contained the highest content of the total phenolic with 34.59 mg gallic acid equivalent (GAE)/g extract, while the hexane had the highest content of the total flavonoid (20.06 mg rutin equivalent (RE)/g extract). In antioxidant assays, the polar extracts (ethanol, ethanol/water and water) exhibited stronger radical scavenging and reducing power abilities when compared to non-polar extracts. The hexane extract showed the best AChE, tyrosinase and glucosidase inhibitory effects. All extracts revealed effective anti-inflammatory agents, as demonstrated by the blunting effects on COX-2 and TNFα gene expression. These effects seemed to be not related to the only phenolic content. However, it is worthy of interest to highlight how the higher potency against LPS-induced gene expression was shown by the water extract ; thus suggesting a potential phytotherapy application in the management of clinical symptoms related to inflammatory colon diseases, although future in vivo studies are needed to confirm such in vitro and ex vivo observations.

Inhibition of Cysteine Proteases via Thiol-Michael Addition Explains the Anti-SARS-CoV-2 and Bioactive Properties of Arteannuin B

Artemisia annua is the plant that produces artemisinin, an endoperoxide-containing sesquiterpenoid used for the treatment of malaria. A. annua extracts, which contain other bioactive compounds, have been used to treat other diseases, including cancer and COVID-19, the disease caused by the virus SARS-CoV-2. In this study, a methyl ester derivative of arteannuin B was isolated when A. annua leaves were extracted with a 1:1 mixture of methanol and dichloromethane. This methyl ester was thought to be formed from the reaction between arteannuin B and the extracting solvent, which was supported by the fact that arteannuin B underwent 1,2-addition when it was dissolved in deuteromethanol. In contrast, in the presence of N-acetylcysteine methyl ester, a 1,4-addition (thiol-Michael reaction) occurred. Arteannuin B hindered the activity of the SARS CoV-2 main protease (nonstructural protein 5, NSP5), a cysteine protease, through time-dependent inhibition. The active site cysteine residue of NSP5 (cysteine-145) formed a covalent bond with arteannuin B as determined by mass spectrometry. In order to determine whether cysteine adduction by arteannuin B can inhibit the development of cancer cells, similar experiments were performed with caspase-8, the cysteine protease enzyme overexpressed in glioblastoma. Time-dependent inhibition and cysteine adduction assays suggested arteannuin B inhibits caspase-8 and adducts to the active site cysteine residue (cysteine-360), respectively. Overall, these results enhance our understanding of how A. annua possesses antiviral and cytotoxic activities.

Secondary Metabolites Isolated from Artemisia afra and Artemisia annua and Their Anti-Malarial, Anti-Inflammatory and Immunomodulating Properties-Pharmacokinetics and Pharmacodynamics: A Review

There are over 500 species of the genus Artemisia in the Asteraceae family distributed over the globe, with varying potentials to treat different ailments. Following the isolation of artemisinin (a potent anti-malarial compound with a sesquiterpene backbone) from Artemisia annua, the phytochemical composition of this species has been of interest over recent decades. Additionally, the number of phytochemical investigations of other species, including those of Artemisia afra in a search for new molecules with pharmacological potentials, has increased in recent years. This has led to the isolation of several compounds from both species, including a majority of monoterpenes, sesquiterpenes, and polyphenols with varying pharmacological activities. This review aims to discuss the most important compounds present in both plant species with anti-malarial properties, anti-inflammatory potentials, and immunomodulating properties, with an emphasis on their pharmacokinetics and pharmacodynamics properties. Additionally, the toxicity of both plants and their anti-malaria properties, including those of other species in the genus Artemisia, is discussed. As such, data were collected via a thorough literature search in web databases, such as ResearchGate, ScienceDirect, Google scholar, PubMed, Phytochemical and Ethnobotanical databases, up to 2022. A distinction was made between compounds involved in a direct anti-plasmodial activity and those expressing anti-inflammatory and immunomodulating activities or anti-fever properties. For pharmacokinetics activities, a distinction was made between compounds influencing bioavailability (CYP effect or P-Glycoprotein effect) and those affecting the stability of pharmacodynamic active components.

The mint versus Covid hypothesis

Recent lines of evidence suggest the intriguing hypothesis that consuming common culinary herbs of the mint family might help prevent or treat Covid. Individual citizens could easily explore the hypothesis using ordinary kitchen materials. I offer a philosophical framework to account for the puzzling lack of public health messaging about this interesting idea.

A review of efficacy and safety of Ugandan anti-malarial plants with application of RITAM score

BACKGROUND

Malaria, a treatable disease mainly caused by Plasmodium falciparum has remained a health challenge in Africa, a continent that accounted for 96% of total global cases and deaths in 2021. Uganda, a malaria endemic country is experiencing malaria parasite resistance to some of the drugs used in the artemisinin-based combination therapy (ACT). In an effort to prioritize herbal medicines for new product development, this review synthesized the available safety and efficacy literature on the Ugandan anti-malarial plants to suggest most effective herbal plants.

METHODS

Literature was exhaustively searched using engines and databases, such as Google scholar, Pubmed, and Scopus-indexed journals during the period of June 2020-December 2021. In the first phase, information on ethnobotanical uses of anti-malarial plants in Uganda was gathered and synthetized to generate a list of plants, followed by data on anti-malarial efficacy (both in vitro and in vivo) on each listed plant. Minimum inhibitory concentrations (µg/ml), and % parasite suppression for every plant were scored using The Research Initiative on Traditional and Antimalarial Methods (RITAM) scoring system. The best twenty (20) plants were evaluated for acute safety (LD₅₀) data in rat model, plant parts used, ease of cultivation, presence of clinical studies and other relevant factors for suggesting the best three (3) plants for future anti-malarial product development.

RESULTS

Over one hundred twenty-six (126) plant species are used in Uganda for treatment of malaria in local communities. Out of these, about 33% (41) have been studied for efficacy and safety, with Artemisia annua and Vernonia amygdalina being the most extensively studied and among the best twenty (20) anti-malarial plants in Uganda. Both are limited by parasite recrudescence in clinical studies. Microglossa pyrifolia, a very potent plant (IC50 = 0.03 - 0.05 µg/ml has potential to penetrate the liver and could ameliorate the challenge of recrudescence if combined with A. annua and V. amygdalina in a polyherbal formulation.

CONCLUSION

There are many plants with promising potential for malaria treatment in Uganda and a herbal combination of A. annua, V. amydalina and M. pyrifolia could offer the next herbal ACT if carefully studied and developed.

Aqueous Extract of Artemisia annua Shows In Vitro Antimicrobial Activity and an In Vivo Chemopreventive Effect in a Small-Cell Lung Cancer Model

Artemisia annua (A. annua) has been used as a medicinal plant in the treatment of several infectious and non-infectious diseases in the forms of tea and press juice since ancient times. The aim of this study was to evaluate the aqueous extract of A. annua (AAE) as an antimicrobial agent in vitro and to evaluate its chemopreventive efficacy in vivo in a small-cell lung cancer (SCLC) animal model. The dried powder of AAE was prepared using the Soxhlet extraction system from the leaves of Artemisia annua. The in vitro activity of AAE was determined against Candida albicans (C. albicans), Enterococcus faecalis (E. faecalis), Klebsiella pneumoniae (K. pneumoniae), and methicillin-resistant Staphylococcus aureus (MRSA) using the agar well diffusion method and propidium iodide (PI)-stained microbial death under a confocal microscope. The pretreatment of mice with AAE was initiated two weeks before the first dose of benzo[a]pyrene and continued for 21 weeks. The chemopreventive potential of the extract was evaluated by flow cytometry and biochemical and histopathological analyses of the tissues and serum accordingly, after sacrificing the mice. The data revealed the antimicrobial potential of AAE against all the species investigated, as it showed growth-inhibitory activity by MIC, as well as confocal microscopy. The pretreatment of AAE exhibited significant protection in carcinogen-modulated, average body weight (ABW), and relative organ weight (ROW) cancer biomarkers in the serum and antioxidants in the lungs. The hematoxylin and eosin (H&E) staining of the tissues revealed that AAE prevented malignancy in the lungs. AAE also induced apoptosis and decreased intracellular reactive oxygen species (ROS) in the lung cells analyzed by flow cytometry. The current findings demonstrated the use of AAE as an alternative medicine in the treatment of infectious disease and the chemoprevention of lung cancer. To our knowledge, this is the first study that summarizes the chemopreventive potential of AAE in a lung cancer model in vivo. However, further investigations are suggested to understand the role of AAE to potentiate the therapeutic index of the commercially available drugs that show multiple drug resistance against microbial growth and high toxicity during cancer chemotherapy.

Reactive Oxygen, Nitrogen, and Sulfur Species (RONSS) as a Metabolic Cluster for Signaling and Biostimulation of Plants: An Overview

This review highlights the relationship between the metabolism of reactive oxygen species (ROS), reactive nitrogen species (RNS), and H2S-reactive sulfur species (RSS). These three metabolic pathways, collectively termed reactive oxygen, nitrogen, and sulfur species (RONSS), constitute a conglomerate of reactions that function as an energy dissipation mechanism, in addition to allowing environmental signals to be transduced into cellular information. This information, in the form of proteins with posttranslational modifications or signaling metabolites derived from RONSS, serves as an inducer of many processes for redoxtasis and metabolic adjustment to the changing environmental conditions to which plants are subjected. Although it is thought that the role of reactive chemical species was originally energy dissipation, during evolution they seem to form a cluster of RONSS that, in addition to dissipating excess excitation potential or reducing potential, also fulfils essential signaling functions that play a vital role in the stress acclimation of plants. Signaling occurs by synthesizing many biomolecules that modify the activity of transcription factors and through modifications in thiol groups of enzymes. The result is a series of adjustments in plants' gene expression, biochemistry, and physiology. Therefore, we present an overview of the synthesis and functions of the RONSS, considering the importance and implications in agronomic management, particularly on the biostimulation of crops.

Efficacy of Artemisia annua against Coccidiosis in Broiler Chickens: A Field Trial

(1) Background: Various studies on artemisinin and its derivatives have shown that Artemisia annua may be of therapeutic interest for different diseases, including chicken coccidiosis. This study aimed to evaluate the effects of Artemisia annua on farm-reared broiler chickens by analyzing both the anticoccidial efficacy and its effect on the intestinal microbiota of poultry. (2) Methods: The experiment was performed within three houses on a broiler chicken farm located in Romania. House 1 was the experimental group and received a diet with an addition of A. annua. Houses 2 and 4 were the control groups and received anticoccidials. The prophylactic efficacy of A. annua against coccidiosis was evaluated by recording the weight gain, feed conversion rate, number of oocysts per gram of feces, lesion score, and mortality rate. (3) Results: The chickens fed with A. annua showed a decreasing trend in the number of oocysts per gram of faeces, and their lesion score was 80% lower than in the control group. The weight gains of the chickens treated with A. annua was lower, whilst the feed conversion rate was better than in controls. (4) Conclusions: Artemisia annua showed promising results in the prophylaxis of coccidiosis. Overall, the broiler chickens that received A. annua presented promising zootechnical performances and medical data related to coccidiosis and gut microbiota.

Artemisia Species with High Biological Values as a Potential Source of Medicinal and Cosmetic Raw Materials

Artemisia species play a vital role in traditional and contemporary medicine. Among them, Artemisia abrotanum, Artemisia absinthium, Artemisia annua, Artemisia dracunculus, and Artemisia vulgaris are the most popular. The chemical composition and bioactivity of these species have been extensively studied. Studies on these species have confirmed their traditional applications and documented new pharmacological directions and their valuable and potential applications in cosmetology. Artemisia ssp. primarily contain sesquiterpenoid lactones, coumarins, flavonoids, and phenolic acids. Essential oils obtained from these species are of great biological importance. Extracts from Artemisia ssp. have been scientifically proven to exhibit, among others, hepatoprotective, neuroprotective, antidepressant, cytotoxic, and digestion-stimulating activities. In addition, their application in cosmetic products is currently the subject of several studies. Essential oils or extracts from different parts of Artemisia ssp. have been characterized by antibacterial, antifungal, and antioxidant activities. Products with Artemisia extracts, essential oils, or individual compounds can be used on skin, hair, and nails. Artemisia products are also used as ingredients in skincare cosmetics, such as creams, shampoos, essences, serums, masks, lotions, and tonics. This review focuses especially on elucidating the importance of the most popular/important species of the Artemisia genus in the cosmetic industry.

Targeting the Plasmodium falciparum’s Thymidylate Monophosphate Kinase for the Identification of Novel Antimalarial Natural Compounds

Recent reports of resistance to artemisinin-based combination drugs necessitate the need to discover novel antimalarial compounds. The present study was aimed at identifying novel antimalarial compounds from natural product libraries using computational methods. Plasmodium falciparum is highly dependent on the pyrimidine biosynthetic pathway, a de novo pathway responsible for the production of pyrimidines, and the parasite lacks the pyrimidine salvage enzymes. The P. falciparum thymidylate monophosphate kinase (PfTMPK) is an important protein necessary for rapid DNA replication; however, due to its broad substrate specificity, the protein is distinguished from its homologs, making it a suitable drug target. Compounds from AfroDB, a database of natural products originating from Africa, were screened virtually against PfTMPK after filtering the compounds for absorption, distribution, metabolism, excretion, and toxicity (ADMET)-acceptable compounds with FAF-Drugs4. Thirteen hits with lower binding energies than thymidine monophosphate were selected after docking. Among the thirteen compounds, ZINC13374323 and ZINC13365918 with binding energies of −9.4 and −8.9 kcal/mol, respectively, were selected as plausible lead compounds because they exhibited structural properties that ensure proper binding at the active site and inhibitory effect against PfTMPK. ZINC13374323 (also called aurantiamide acetate) is known to exhibit anti-inflammatory and antiviral activities, and ZINC13365918 exhibits antileishmanial activity. Furthermore, aurantiamide acetate, which is commercially available, is a constituent of Artemisia annua, the herb from which artemisinin was derived. The compound also shares interactions with several residues with a potent thymidine analog inhibitor of PfTMPK. The anti-plasmodial activity of aurantiamide acetate was evaluated in vitro, and the mean half-maximal inhibitory concentration (IC50) was 69.33 μM when synchronized P. falciparum 3D7 culture was used as compared to IC50 > 100 μM with asynchronized culture. The significance of our findings within the context of malaria treatment strategies and challenges is discussed.

Combination of artesunate and WNT974 induces KRAS protein degradation by upregulating E3 ligase ANACP2 and β-TrCP in the ubiquitin–proteasome pathway

Background

KRAS mutation is one of the dominant gene mutations in colorectal cancer (CRC). Up to present, targeting KRAS for CRC treatment remains a clinical challenge. WNT974 (LGK974) is a porcupine inhibitor that interferes Wnt signaling pathway. Artesunate (ART) is a water-soluble semi-synthetic derivative of artemisinin.

Methods

The synergistic effect of ART and WNT974 combination in reducing CRC cell viability was determined by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. RT-PCR was utilized for the mRNA levels of KRAS, CUL7, ANAPC2, UBE2M, RNF123, SYVN1, or β-TrCP. Western blot assay was utilized for the protein levels of NRAS, HRAS, KRAS, ANAPC2, β-TrCP, GSK-3β, p-Akt (Ser473), t-Akt, p-PI3K (Tyr458), t-PI3K, p-mTOR (Ser2448), t-mTOR. Xenograft mouse model assay was performed for the anti-CRC effect of combination of ART and WNT974 in vivo. IHC assay was utilized for the levels of KRAS, β-TrCP, GSK-3β or ANAPC2 in tumor tissues.

Results

Our study shows that the combination of WNT974 and ART exhibits synergistic effect in reducing CRC growth. The combination treatment significantly reduces KRAS protein level and activity in CRC cells. Interestingly, the combination treatment increases E3 ligases ANAPC2 expression. Our data show that overexpression of ANAPC2 significantly reduces KRAS protein levels, which is reversed by MG132. Knockdown of ANAPC2 in CRC abolishes the combination treatment-reduce KRAS expression. Besides, the treatment also increases the expressions of GSK-3β and E3 ligase β-TrCP that is known to degrade GSK-3β-phosphorylated KRAS protein. Knockdown of β-TrCP- and inhibition of GSK-3β abolish the combination treatment-induce KRAS ubiquitination and reduction in expression. Last but not least, combination treatment suppresses PI3K/Akt/m-TOR signaling pathway.

Conclusions

Our data clearly show that the combination treatment significantly enhances KRAS protein degradation via the ubiquitination ubiquitin–proteasome pathway, which is also demonstrated in xenograft mouse model. The study provides strong scientific evidence for the development of the combination of WNT974 and ART as KRAS-targeting therapeutics for CRC treatment.

Antiplasmodial activity and cytotoxicity of plant extracts from the Asteraceae and Rubiaceae families

The increasing resistance of parasites to antimalarial drugs and the limited number of effective drugs are the greatest challenges in the treatment of malaria. It is necessary to search for an alternative medicine for use as a new, more effective antimalarial drug. Therefore, this study aimed to evaluate the in vitro antimalarial activity and cytotoxicity of extracts from plants belonging to the Asteraceae and Rubiaceae families. The phytoconstituents of one hundred ten ethanolic and aqueous extracts from different parts of twenty-three plant species were analyzed. Evaluation of their antimalarial activities against the chloroquine (CQ)-resistant Plasmodium falciparum (K1) strain was carried out using the lactate dehydrogenase (pLDH) assay, and their cytotoxicity in Vero cells was assessed using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) colorimetric method. A total of 40.91% of the extracts were active antimalarial agents. Three extracts (2.73%) exhibited high antiplasmodial activity (IC50 < 10 μg/ml), twenty-four extracts (21.82%) were moderately active with IC50 values ranging from 10-50 μg/ml, and eighteen extracts (16.36%) were mildly active with IC50 values ranging from 50-100 μg/ml. The ethanolic leaf extract of Mussaenda erythrophylla (Dona Trining; Rubiaceae) exhibited the highest activity against P. falciparum, with an IC50 value of 3.73 μg/ml and a selectivity index (SI) of 30.74, followed by the ethanolic leaf extract of Mussaenda philippica Dona Luz x M. flava (Dona Marmalade; Rubiaceae) and the ethanolic leaf extract of Blumea balsamifera (Camphor Tree; Asteraceae), with IC50 values of 5.94 and 9.66 μg/ml and SI values of 25.36 and >20.70, respectively. GC-MS analysis of these three plant species revealed the presence of various compounds, such as squalene, oleic acid amide, β-sitosterol, quinic acid, phytol, oleamide, α-amyrin, sakuranin, quercetin and pillion. In conclusion, the ethanolic leaf extract of M. erythrophylla, the leaf extract of M. philippica Dona Luz x M. flava and the leaf extract of B. balsamifera had strong antimalarial properties with minimal toxicity, indicating that compounds from these plant species have the potential to be developed into new antiplasmodial agents.

Transcriptional regulation of flavonoid biosynthesis in Artemisia annua by AaYABBY5

Artemisia annua is a medicinal plant rich in terpenes and flavonoids with useful biological activities such as antioxidant, anticancer, and antimalarial activities. The transcriptional regulation of flavonoid biosynthesis in A. annua has not been well-studied. In this study, we identified a YABBY family transcription factor, AaYABBY5, as a positive regulator of anthocyanin and total flavonoid contents in A. annua. AaYABBY5 was selected based on its similar expression pattern to the phenylalanine ammonia lyase (PAL), chalcone synthase (CHS), chalcone isomerase (CHI), and flavonol synthase (FLS) genes. A transient dual-luciferase assay in Nicotiana bethamiana with the AaYABBY5 effector showed a significant increase in the activity of the downstream LUC gene, with reporters AaPAL, AaCHS, AaCHI, and AaUFGT. The yeast one-hybrid system further confirmed the direct activation of these promoters by AaYABBY5. Gene expression analysis of stably transformed AaYABBY5 overexpression, AaYABBY5 antisense, and control plants revealed a significant increase in the expression of AaPAL, AaCHS, AaCHI, AaFLS, AaFSII, AaLDOX, and AaUFGT in AaYABBY5 overexpression plants. Moreover, their total flavonoid content and anthocyanin content were also found to increase. AaYABBY5 antisense plants showed a significant decrease in the expression of flavonoid biosynthetic genes, as well as a decrease in anthocyanin and total flavonoid contents. In addition, phenotypic analysis revealed deep purple-pigmented stems, an increase in the leaf lamina size, and higher trichome densities in AaYABBY5 overexpression plants. Together, these data proved that AaYABBY5 is a positive regulator of flavonoid biosynthesis in A. annua. Our study provides candidate transcription factors for the improvement of flavonoid concentrations in A. annua and can be further extended to elucidate its mechanism of regulating trichome development.

New insights into the spread of resistance to artemisinin and its analogues

Plasmodium falciparum, the causative agent of malaria, has been developing resistance to several drugs worldwide for more than five decades. Initially, resistance was against drugs such as chloroquine, pyrimethamine, sulfadoxine, mefloquine and quinine. Research studies are now reporting parasites with resistance to the most effective and novel drug used against malaria infection worldwide, namely artemisinin. For this reason, the first-line treatment strategy of artemisinin-based combination therapy is becoming unsuccessful in areas where drug resistance is highly prevalent. The increase in artemisinin-resistant P. falciparum strains has threatened international efforts to eliminate malarial infections and to reduce the disease burden. Detection of several phenotypes that display artemisinin resistance, specification of basic genetic factors, the discovery of molecular pathways, and evaluation of its clinical outcome are possible by the current series of research on genomics and transcriptomic levels in Asia and Africa. In artemisinin resistance, slow parasite clearance among malaria-infected patients and enhanced in vitro survival of parasites occurs at the early ring stage. This resistance is due to single nucleotide polymorphisms within the Kelch 13 gene of the parasite and is related to significantly upregulated resistance signalling pathways; thus, the pro-oxidant action of artemisinins can be antagonised. New strategies are required to halt the spread of artemisinin-resistant malarial parasites.

Compounds Isolated from Wikstroemia taiwanensis Regulate Bone Remodeling by Modulating Osteoblast and Osteoclast Activities

Bone remodeling, a dynamic process in which bone formation by osteoblast is preceded by bone resorption by osteoclast, is a vital physiological process for maintaining bone mass and strength, imbalances in which could precipitate osteoporosis. Due to the unilateral mechanism of the existing bone remodeling drugs, identifying compounds that could regulate the balance between osteoclast and osteoblast could improve the treatment of osteoporosis. Here, we show that compounds isolated from Wikstroemia taiwanensis modulate osteoclast and osteoblast activities. Specifically, astragalin (1) and kaempferol 3-O-β-D-apiofuranosyl-(1→6)-β-D-glucopyranoside (2), besides increasing mineral deposition, increased alkaline phosphatase activity (137.2% for 1 and 115.8% for 2) and ESR-α expression (112.8% for 1 and 122.5% for 2) in primary human osteoblasts. In contrast, compounds 1, 2, 3, and 5 inhibited tartrate-resistant acid phosphatase (TRAP) activity in receptor activator of nuclear factor-κB ligand-induced osteoclasts by 40.8, 17.1, 25.9, and 14.5% and also decreased the number of TRAP-positive cells by 51.6, 26.8, 20.5, and 18.6%, respectively. Our findings, therefore, showed that compounds isolated from W. taiwanensis could increase osteoblast activity while simultaneously decreasing osteoclast activity, and hence, warrant further evaluation for development as anti-osteoporosis agents.

Artemisia annua - Importance in Traditional Medicine and Current State of Knowledge on the Chemistry, Biological Activity and Possible Applications

Artemisia annua (annual mugwort) is a species that has long been used in traditional Asian medicine, mainly Chinese and Hindu. The species is widespread and known as a medicinal plant not only in Asia but also in Europe, in both Americas, and Australia. The species has become a subject of particular interest due to the 2015 Nobel Prize awarded for detecting the sesquiterpene lactone artemisinin in it and proving its antimalarial activities. The raw materials obtained from this species are Artemisiae annuae folium and Artemisiae annuae herba. The leaves are a raw material in the Chinese Pharmacopoeia and Vietnamese Pharmacopoeia. Both raw materials are in the International Pharmacopoeia published by the WHO. The main components of these raw materials are mainly specific sesquiterpene lactones, essential oil, flavonoids, coumarins, and phenolic acids. In traditional Asian medicine, the species is used, for example, in the treatment of jaundice and bacterial dysentery, as an antipyretic agent in malaria and tuberculosis, in the treatment of wounds and haemorrhoids, and in viral, bacterial, and autoimmune diseases. Professional pharmacological studies conducted today have confirmed its known traditional applications and explain previously unknown mechanisms of its biological action and have also found evidence of new directions of biological activity, including, among others, anti-inflammatory, analgesic, antioxidant, antitumour, and nephroprotective activities. The species is of growing importance in the cosmetics industry.

Insights into oral bioavailability enhancement of therapeutic herbal constituents by cytochrome P450 3A inhibition

Herbal plants typically have complex compositions and diverse mechanisms. Among them, bioactive constituents with relatively high exposure in vivo are likely to exhibit therapeutic efficacy. On the other hand, their bioavailability may be influenced by the synergistic effects of different bioactive components. Cytochrome P450 3A (CYP3A) is one of the most abundant CYP enzymes, responsible for the metabolism of 50% of approved drugs. In recent years, many therapeutic herbal constituents have been identified as CYP3A substrates. It is more evident that CYP3A inhibition derived from the herbal formula plays a critical role in improving the oral bioavailability of therapeutic constituents. CYP3A inhibition may be the mechanism of the synergism of herbal formula. In this review, we explored the multiplicity of CYP3A, summarized herbal monomers with CYP3A inhibitory effects, and evaluated herb-mediated CYP3A inhibition, thereby providing new insights into the mechanisms of CYP3A inhibition-mediated oral herb bioavailability.

In vitro analyses of Artemisia extracts on Plasmodium falciparum suggest a complex antimalarial effect

Dried-leaf Artemisia annua L. (DLA) antimalarial therapy was shown effective in prior animal and human studies, but little is known about its mechanism of action. Here IC50s and ring-stage assays (RSAs) were used to compare extracts of A. annua (DLAe) to artemisinin (ART) and its derivatives in their ability to inhibit and kill Plasmodium falciparum strains 3D7, MRA1252, MRA1240, Cam3.11 and Cam3.11rev in vitro. Strains were sorbitol and Percoll synchronized to enrich for ring-stage parasites that were treated with hot water, methanol and dichloromethane extracts of DLA, artemisinin, CoArtem™, and dihydroartemisinin. Extracts of A. afra SEN were also tested. There was a correlation between ART concentration and inhibition of parasite growth. Although at 6 hr drug incubation, the RSAs for Cam3.11rev showed DLA and ART were less effective than high dose CoArtem™, 8 and 24 hr incubations yielded equivalent antiparasitic results. For Cam3.11, drug incubation time had no effect. DLAe was more effective on resistant MRA-1240 than on the sensitive MRA-1252 strain. Because results were not as robust as observed in animal and human studies, a host interaction was suspected, so sera collected from adult and pediatric Kenyan malaria patients was used in RSA inhibition experiments and compared to sera from adults naïve to the disease. The sera from both age groups of malaria patients inhibited parasite growth ≥ 70% after treatment with DLAe and compared to malaria naïve subjects suggesting some host interaction with DLA. The discrepancy between these data and in-vivo reports suggested that DLA’s effects require an interaction with the host to unlock their potential as an antimalarial therapy. Although we showed there are serum-based host effects that can kill up to 95% of parasites in vitro, it remains unclear how or if they play a role in vivo. These results further our understanding of how DLAe works against the malaria parasite in vitro.

The potential of Artemisia species for use as broad-spectrum agents in the management of metabolic syndrome: a review

Although the prevalence of metabolic syndrome (MetS), a cluster of cardiometabolic risk factors that predispose to the development of type 2 diabetes mellitus and cardiovascular diseases, is increasing globally, there is no broad-spectrum agent for its holistic treatment. Natural plant-derived products with a wide spectrum of biological activities are currently being explored as alternatives in the management of diseases. Artemisia species are a heterozygous group of plants of the Compositae family that possess several health benefits. Here we highlight their antidiabetic, anti-obesity, anti-hyperlipidaemic, hepatoprotective and cardioprotective properties among others. These activities have been linked to the presence of phytochemicals that act on several molecular targets to exert their effects and the species of Artemisia are considered to be relatively safe. Artemisia species offer significant anti-MetS activity and thus are strong therapeutic candidates for the effective management of MetS.

It is not just artemisinin: Artemisia sp. for treating diseases including malaria and schistosomiasis

Artemisia sp., especially A. annua and A. afra, have been used for centuries to treat many ailments. While artemisinin is the main therapeutically active component, emerging evidence demonstrates that the other phytochemicals in this genus are also therapeutically active. Those compounds include flavonoids, other terpenes, coumarins, and phenolic acids. Artemisia sp. phytochemicals also improve bioavailability of artemisinin and synergistically improve artemisinin therapeutic efficacy, especially when delivered as dried leaf Artemisia as a tea infusion or as powdered dry leaves in a capsule or compressed into a tablet. Here results from in vitro, and in vivo animal and human studies are summarized and critically discussed for mainly malaria, but also other diseases susceptible to artemisinin and Artemisia sp. including schistosomiasis, leishmaniasis, and trypanosomiasis.

Liquid chromatography-tandem mass spectrometry assay for the simultaneous determination of three major flavonoids and their glucuronidated metabolites in rats after oral administration of Artemisia annua L. extract at a therapeutic ultra-low dose

The traditional antimalarial herb Artemisia annua L., from which artemisinin is isolated, is widely used in endemic regions. It has been suggested that artemisinin activity can be enhanced by flavonoids in A. annua; however, how fast and how long the flavonoids are present in the body remains unknown. In the present study, a rapid and sensitive liquid chromatography with tandem mass spectrometry method was developed and validated for the simultaneous determination of three major flavonoids components, i.e. chrysosplenol D, chrysoplenetin, and artemetin and their glucuronidated metabolites in rats after oral administrations of A. annua extracts at a therapeutic ultra-low dose. The concentration of the intact form was determined directly, and the concentration of the glucuronidated form was assayed in the form of flavonoids aglycones, after treatment with β-glucuronidase/sulfatase. The method was linear in the range of 0.5-300.0 ng/mL for chrysoplenetin and artemetin, and 2-600 ng/mL for chrysosplenol D. All the validation data conformed to the acceptance requirements. The study revealed a significantly higher exposure of the flavonoid constituents in conjugated forms in rats, with only trace intact from. Multiple oral doses of A. annua extracts led to a decreased plasma concentration levels for three flavonoids.

In vitro antiplasmodial, antitrypanosomal and antileishmanial activities of selected medicinal plants from Ugandan flora: Refocusing into multi-component potentials

ETHNOPHARMACOLOGICAL RELEVANCE

Seven medicinal plants from Ugandan flora, namely Entada abyssinica, Khaya anthotheca, Vernonia amygdalina, Baccharoides adoensis, Schkuhria pinnata, Entandropragma utile and Momordica foetida, were selected in this study. They are used to treat conditions and infections ranging from inflammations, pains and fevers to viruses, bacteria, protozoans and parasites. Two of the plants, V. amygdalina and M. foetida, are also used as human food or relish, while others are important in ethnoveterinary practices and in zoopharmacognosy in the wild. The aim of this study was to evaluate the in vitro antiplasmodial, antitrypanosomal and antileishmanial activities, along with cytotoxicity of the multi-component extracts of these plants.

MATERIALS AND METHODS

Different parts of the plants were prepared and serially extracted with hexane, petroleum ether, dichloromethane, ethyl acetate, methanol and double distilled water. Solvent free extracts were assayed for in vitro inhibition against four reference parasite strains, Plasmodium falciparum (K1), Trypanosoma brucei rhodesiense (STIB 900), Trypanosoma cruzi (Talahuen C2C4) and Leishmania donovani (MHOM-ET-67/L82) using standard methods. Toxicity was assessed against L6 skeletal fibroblast and mouse peritoneal macrophage (J774) cells and selectivity indices (SIs) calculated for the most active extracts.

RESULTS

The strongest activities, demonstrating median inhibitory concentration (IC₅₀) values ≤ 2 μg/ml, were observed for the dichloromethane and petroleum ether extracts of K. anthotheca, B. adoensis and S. pinnata. Overall, IC₅₀ values ranged from < 1 μg/ml to > 90 μg/ml. Out of 22 extracts demonstrating IC_50s < 20 μg/ml, seven were against T. b. rhodesiense (IC₅₀: 1.6-16.2 μg/ml), six against T. cruzi (IC₅₀: 2.1-18.57 μg/ml), none against L. donovani (IC₅₀: falling > 3.3 and >10 μg/ml), and nine against P. falciparum (IC₅₀: 0.96 μg/ml to 4.69 μg/ml). Selectivity indices (SI) calculated for the most active extracts ranged from <1.00 to 94.24. However, the B. adoensis leaf dichloromethane extract (a) was equipotent (IC₅₀ = 3.3 μg/ml) against L. donovani and L6 cells respectively, indicating non-specific selection. Trypanosome and Plasmodium parasites were comparatively more sensitive to the test extracts.

CONCLUSIONS

The benefits achieved from the seven tested plant species as traditional ethnomedicinal and ethnoveterinary therapies or in zoopharmacognosy against infections and conditions of animals in the wild are strongly supported by results of this study. The synergy of plant extracts, so achieved by concerted actions of the ligands, produces adequate perturbation of targets in the four parasite genera, resulting in the strong potencies exhibited by low IC₅₀ values. The total inhibitory effect, achieved as a sum of perturbations contributed by each participating compound in the extract, minimises toxic effects of the compounds as seen in the high SI's obtained with some extracts. Those extracts demonstrating SI ≥ 4 form promising candidates for further cell-based and system pharmacology studies.

Flavonoid Versus Artemisinin Anti-malarial Activity in Artemisia annua Whole-Leaf Extracts

Artemisinin, a sesquiterpene lactone produced by Artemisia annua glandular secretory trichomes, is the active ingredient in the most effective treatment for uncomplicated malaria caused by Plasmodium falciparum parasites. Other metabolites in A. annua or related species, particularly flavonoids, have been proposed to either act as antimalarials on their own or act synergistically with artemisinin to enhance antimalarial activity. We identified a mutation that disrupts the CHALCONE ISOMERASE 1 (CHI1) enzyme that is responsible for the second committed step of flavonoid biosynthesis. Detailed metabolite profiling revealed that chi1-1 lacks all major flavonoids but produces wild-type artemisinin levels, making this mutant a useful tool to test the antiplasmodial effects of flavonoids. We used whole-leaf extracts from chi1-1 and mutant lines impaired in artemisinin production in bioactivity in vitro assays against intraerythrocytic P. falciparum Dd2. We found that chi1-1 extracts did not differ from wild-type extracts in antiplasmodial efficacy nor initial rate of cytocidal action. Furthermore, extracts from the A. annua cyp71av1-1 mutant and RNAi lines impaired in amorpha-4,11-diene synthase gene expression, which are both severely compromised in artemisinin biosynthesis but unaffected in flavonoid metabolism, showed very low or no antiplasmodial activity. These results demonstrate that in vitro bioactivity against P. falciparum of flavonoids is negligible when compared to that of artemisinin.

Lack of impact of dietary inclusion of dried Artemisia annua leaves for cattle on infestation by Rhipicephalus (Boophilus) microplus ticks

The present study evaluated whether a natural dietary additive, dried Artemisia annua leaves, may be useful to control Rhipicephalus (Boophilus) microplus on naturally infested cattle. Twenty heifers of the Canchim breed, weighing around 250 kg, were divided into two equally sized experimental groups: 1) control animals and 2) animals receiving 200 g/day of dried A. annua leaves for two months. Before treatment began, the animals were homogeneously distributed in control and treatment groups based on their pre-treatment weight and tick infestation level. Counts of engorged female ticks then occurred weekly during the two-month experimental period. We also monitored cattle weight gain and packed cell volume (PCV). Artemisinin (0.96%) was quantified in the plant material by high-performance liquid chromatography with refractive index detector (HPLC-IR). No statistical differences between the control and treatment groups were observed for engorged female counts (log averages of 1.3 ticks and 1.4 ticks per animal, respectively), daily cattle weight gain (0.910 kg and 0.888 kg, respectively) or PCV (33.5% and 33.0%, respectively). We conclude that the oral supplementation of cattle feed with dried A. annuna leaves did not control natural infestation of R. (B.) microplus. The hypothesis of artemisinin's action on cattle ticks by ingestion through the animals' blood was not confirmed at the evaluated dose.

Biotechnological approaches for artemisinin production in Artemisia

Abstract

Artemisinin and its analogues are naturally occurring most effective antimalarial secondary metabolites. These compounds also possess activity against various types of cancer cells, schistosomiasis, and some viral diseases. Artemisinin and its derivatives (A&D) are found in very low amounts in the only natural source i.e. Artemisia plant. To meet the global needs, plant sources have been exploited for the enhanced production of these natural products because their chemical synthesis is not profitable. The generally adopted approaches include non-transgenic (tissue and cell cultures) and transgenic together with the cell, tissue, and whole transgenic plant cultures. The genes targeted for the overproduction of A&D include the biosynthetic pathway genes, trichome development genes and rol genes, etc. Artemisinin is naturally produced in trichomes of leaves. At the same time, transgenic hairy roots are considered a good source to harvest artemisinin. However, the absence of trichomes in hairy roots suggests that artemisinin biosynthesis is not limited to trichomes. Moreover, the expression of the gene involved in trichome development and sesquiterpenoid biosynthesis (TFAR1) in transgenic and non-transgenic roots provokes researchers to look for new insight of artemisinin biosynthesis. Here we discuss and review precisely the various biotechnological approaches for the enhanced biosynthesis of A&D.

Graphical Abstract

Artemisia annua dried leaf tablets treated malaria resistant to ACT and i.v. artesunate: Case reports

BACKGROUND

Dried leaf Artemisia annua (DLA) has shown efficacy against Plasmodium sp. in rodent studies and in small clinical trials. Rodent malaria also showed resiliency against the evolution of artemisinin drug resistance.

PURPOSE

This is a case report of a last resort treatment of patients with severe malaria who were responding neither to artemisinin combination therapy (ACT) nor i.v. artesunate.

STUDY DESIGN

Of many patients treated with ACTs and i.v. artesunate during the 6 mon study period, 18 did not respond and were subsequently treated with DLA Artemisia annua.

METHODS

Patients were given a dose of 0.5g DLA per os, twice daily for 5d. Total adult delivered dose of artemisinin was 55mg. Dose was reduced for body weight under 30kg. Clinical symptoms, e.g. fever, coma etc., and parasite levels in thick blood smears were tracked. Patients were declared cured and released from hospital when parasites were microscopically undetectable and clinical symptoms fully subsided.

RESULTS

All patients were previously treated with Coartem® provided through Santé Rurale (SANRU) and following the regimen prescribed by WHO. Of 18 ACT-resistant severe malaria cases compassionately treated with DLA, all fully recovered. Of the 18, this report details two pediatric cases.

CONCLUSIONS

Successful treatment of all 18 ACT-resistant cases suggests that DLA should be rapidly incorporated into the antimalarial regimen for Africa and possibly wherever else ACT resistance has emerged.

Investigation of the component in Artemisia annua L. leading to enhanced antiplasmodial potency of artemisinin via regulation of its metabolism

ETHNOPHARMACOLOGICAL RELEVANCE

The chemical matrix of the herb Artemisia annua L. (A. annua), from which artemisinin (QHS) is isolated, can enhance both the bioavailability and efficacy of QHS. However, the exact mechanism of this synergism remains unknown. The biotransformation of QHS and potential "enzyme inhibitors" in plant matrix could be of great importance in understanding the improved efficacy of QHS in A. annua, which has been limited to the synergism with flavonoid components.

AIM OF THE STUDY

To investigate the component in A. annua extracts (MAE) leading to enhanced antiplasmodial potency of QHS via regulation of its metabolism. The efficacy of QHS in combination with the synergistic component was also evaluated.

MATERIALS AND METHODS

The total MAE extract and its three MAE fractions (MAE-I eluted using 3% methanol, MAE-II eluted using 50% methanol and MAE-III eluted using 85% methanol) were obtained from dry plant materials and prepared after lyophilization. The pharmacokinetic profiles of QHS and its major phase I metabolite monohydroxylated artemisinin (QHS-M) were investigated in healthy rats after a single oral administration of QHS in each MAE extract. Major components isolated from the target MAE fraction were evaluated for their enzyme inhibition. The antimalarial activity of QHS in combination with the potential synergistic component against Plasmodium falciparum was studied in vivo (murine Plasmodium yoelii). The recrudescence and survival time of infected mice were also recorded after drug treatment.

RESULTS

Compared to pure QHS, a 2-fold increase in QHS exposure (AUC and C_max) was found in healthy rats after a single oral dose of QHS in the total MAE extract or its fraction MAE-III. In addition, metabolic biotransformation of QHS to the metabolite QHS-M (mediated by CYP3A) was inhibited by MAE or MAE-III. Among nine major components isolated from MAE-III (five sesquiterpenenes, three flavonoids and one phenolic acid), only arteannuin B (AB) showed an inhibition of CYP3A4 (IC₅₀ 1.2μM). The synergism between QHS and AB was supported using in vivo antiplasmodial assay and a pharmacokinetic study in mice. Unfortunately, the synergism cannot reduce the rate of recrudescence.

CONCLUSIONS

AB was one of main contributors in A. annua leading to enhanced antiplasmodial potency of QHS via regulation of its metabolism. The final recrudescence indicated the careful use of A. annua for malaria treatment unless additional contributing components or antiplasmodial mechanism were found.

In vitro and in vivo antileishmanial activity of Artemisia annua L. leaf powder and its potential usefulness in the treatment of uncomplicated cutaneous leishmaniasis in humans

INTRODUCTION:

Cutaneous leishmaniasis (CL) is a tropical disease that affects millions of individuals worldwide. The current drugs for CL may be effective but have serious side effects; hence, alternatives are urgently needed. Although plant-derived materials are used for the treatment of various diseases in 80% of the global population, the validation of these products is essential. Gelatin capsules containing dried Artemisia annua leaf powder were recently developed as a new herbal formulation (totum) for the oral treatment of malaria and other parasitic diseases. Here, we aimed to determine the usefulness of A. annua gel capsules in CL.

METHODS:

The antileishmanial activity and cytotoxicity of A. annua L. capsules was determined via in vitro and in vivo studies. Moreover, a preliminary evaluation of its therapeutic potential as antileishmanial treatment in humans was conducted in 2 patients with uncomplicated CL.

RESULTS:

Artemisia annua capsules showed moderate in vitro activity in amastigotes of Leishmania (Viannia) panamensis; no cytotoxicity in U-937 macrophages or genotoxicity in human lymphocytes was observed. Five of 6 (83.3%) hamsters treated with A. annua capsules (500mg/kg/day) for 30 days were cured, and the 2 examined patients were cured 45 days after initiation of treatment with 30g of A. annua capsules, without any adverse reactions. Both patients remained disease-free 26 and 24 months after treatment completion.

CONCLUSION:

Capsules of A. annua L. represent an effective treatment for uncomplicated CL, although further randomized controlled trials are needed to validate its efficacy and safety.

Exploring the antimalarial potential of whole Cymbopogon citratus plant therapy

ETHNOPHARMACOLOGICAL RELEVANCE

Cymbopogon citratus (lemon grass) has been used in traditional medicine as an herbal infusion to treat fever and malaria. Generally, whole plant extracts possess higher biological activity than purified compounds. However, the antimalarial activity of the whole C. citratus plant has not been experimentally tested.

AIM OF THE STUDY

To evaluate the antimalarial activity of an herbal infusion and the whole Cymbopogon citratus plant in two experimental models of malaria.

MATERIAL AND METHODS

The plant was dried for 10 days at room temperature and was then milled and passed through brass sieves to obtain a powder, which was administered to CBA/Ca mice with a patent Plasmodium chabaudi AS or P. berghei ANKA infection. We analysed the effects of two different doses (1600 and 3200mg/kg) compared with those of the herbal infusion and chloroquine, used as a positive control. We also assessed the prophylactic antimalarial activities of the whole C. citratus plant and the combination of the whole plant and chloroquine.

RESULTS

The C. citratus whole plant exhibited prolonged antimalarial activity against both P. chabaudi AS and P. berghei ANKA. The low dose of the whole C. citratus plant displayed higher antimalarial activity than the high dose against P. berghei ANKA. As a prophylactic treatment, the whole plant exhibited higher antimalarial activity than either the herbal infusion or chloroquine. In addition, the combination of the whole C. citratus plant and chloroquine displayed higher activity than chloroquine alone against P. berghei ANKA patent infection.

CONCLUSIONS

We demonstrated the antimalarial activity of the whole C. citratus plant in two experimental models. The whole C. citratus plant elicited higher anti-malarial activity than the herbal infusion or chloroquine when used as a prophylactic treatment. The antimalarial activity of the whole C. citratus plant supports continued efforts towards developing whole plant therapies for the management of malaria and other infectious diseases prevalent in resource-poor communities.

Cardioprotection by combination of three compounds from ShengMai preparations in mice with myocardial ischemia/reperfusion injury through AMPK activation-mediated mitochondrial fission

GRS is a drug combination of three active components including ginsenoside Rb1, ruscogenin and schisandrin. It derived from the well-known TCM formula ShengMai preparations, a widely used traditional Chinese medicine for the treatment of cardiovascular diseases in clinic. The present study explores the cardioprotective effects of GRS on myocardial ischemia/reperfusion (MI/R) injury compared with ShengMai preparations and investigates the underlying mechanisms. GRS treatment significantly attenuated MI/R injury and exhibited similar efficacy as Shengmai preparations, as evidenced by decreased myocardium infarct size, ameliorated histological features, the decrease of LDH production and improved cardiac function, and also produced a significant decrease of apoptotic index. Mechanistically, GRS alleviated myocardial apoptosis by inhibiting the mitochondrial mediated apoptosis pathway as reflected by inhibition of caspase-3 activity, normalization of Bcl-2/Bax levels and improved mitochondrial function. Moreover, GRS prevented cardiomyocytes mitochondrial fission and upregulated AMPKα phosphorylation. Interestingly, AMPK activation prevented hypoxia and reoxygenation induced mitochondrial fission in cardiomyocytes and GRS actions were significantly attenuated by knockdown of AMPKα. Collectively, these data show that GRS is effective in mitigating MI/R injury by suppressing mitochondrial mediated apoptosis and modulating AMPK activation-mediated mitochondrial fission, thereby providing a rationale for future clinical applications and potential therapeutic strategy for MI/R injury.

A Systematic Review of Anti-malarial Properties, Immunosuppressive Properties, Anti-inflammatory Properties, and Anti-cancer Properties of Artemisia Annua

Artemisia annua belongs to the asteraceae family, indigenous to the mild climate of Asia. The aim of this study was to overview its anti-malarial properties, immunosuppressive properties, anti-inflammatory properties and anti-cancer properties. This systematic review was carried out by searching studies in PubMed, Medline, Web of Science, and IranMedex databases. The initial search strategy identified approximately ninety eight references. In this study, forty six studies were accepted for further screening and met all of our inclusion. The search terms were "Artemisia annua", "therapeutic properties", "and pharmacological effects". Artemisia annua is commonly used for its anti-malarial, immunosuppressive anti-inflammatory properties. Artemisia annua contributes to the treatment of various diseases such as diabetes, heart diseases, arthritis and eczema and possesses various effects such as antibacterial, antioxidant, anticoccidial, and antiviral effects. Furthermore, it was said to be good for cancer treatment. In this study, anti-malarial, immunosuppressive, anti-inflammatory properties of this plant are presented using published articles in scientific sites.

Asteraceae Artemisia campestris and Artemisia herba-alba Essential Oils Trigger Apoptosis and Cell Cycle Arrest in Leishmania infantum Promastigotes

We report the chemical composition and anti-Leishmania and antioxidant activity of Artemisia campestris L. and Artemisia herba-alba Asso. essential oils (EOs). Our results showed that these extracts exhibit different antioxidant activities according to the used assay. The radical scavenging effects determined by DPPH assay were of IC50 = 3.3 mg/mL and IC50 = 9.1 mg/mL for Artemisia campestris and Artemisia herba-alba essential oils, respectively. However, antioxidant effects of both essential oils, determined by ferric-reducing antioxidant power (FRAP) assay, were in the same range (2.3 and 2.97 mg eq EDTA/g EO, resp.), while the Artemisia herba-alba essential oil showed highest chelating activity of Fe2+ ions (27.48 mM Fe2+). Interestingly, we showed that both EOs possess dose-dependent activity against Leishmania infantum promastigotes with IC50 values of 68 μg/mL and 44 μg/mL for A. herba-alba and A. campestris, respectively. We reported, for the first time, that antileishmanial activity of both EOs was mediated by cell apoptosis induction and cell cycle arrest at the sub-G0/G1 phase. All our results showed that EOs from A. herba-alba and A. campestris plants are promising candidates as anti-Leishmania medicinal products.

Artemisinin-based antimalarial research: application of biotechnology to the production of artemisinin, its mode of action, and the mechanism of resistance of Plasmodium parasites

Malaria is a worldwide disease caused by Plasmodium parasites. A sesquiterpene endoperoxide artemisinin isolated from Artemisia annua was discovered and has been accepted for its use in artemisinin-based combinatorial therapies, as the most effective current antimalarial treatment. However, the quantity of this compound produced from the A. annua plant is very low, and the availability of artemisinin is insufficient to treat all infected patients. In addition, the emergence of artemisinin-resistant Plasmodium has been reported recently. Several techniques have been applied to enhance artemisinin availability, and studies related to its mode of action and the mechanism of resistance of malaria-causing parasites are ongoing. In this review, we summarize the application of modern technologies to improve the production of artemisinin, including our ongoing research on artemisinin biosynthetic genes in other Artemisia species. The current understanding of the mode of action of artemisinin as well as the mechanism of resistance against this compound in Plasmodium parasites is also presented. Finally, the current situation of malaria infection and the future direction of antimalarial drug development are discussed.

YiXin-Shu, a ShengMai-San-based traditional Chinese medicine formula, attenuates myocardial ischemia/reperfusion injury by suppressing mitochondrial mediated apoptosis and upregulating liver-X-receptor α

Positive evidence from clinical trials has fueled growing acceptance of traditional Chinese medicine (TCM) for the treatment of cardiac diseases; however, little is known about the underlying mechanisms. Here, we investigated the nature and underlying mechanisms of the effects of YiXin-Shu (YXS), an antioxidant-enriched TCM formula, on myocardial ischemia/reperfusion (MI/R) injury. YXS pretreatment significantly reduced infarct size and improved viable myocardium metabolism and cardiac function in hypercholesterolemic mice. Mechanistically, YXS attenuated myocardial apoptosis by inhibiting the mitochondrial mediated apoptosis pathway (as reflected by inhibition of mitochondrial swelling, cytochrome c release and caspase-9 activity, and normalization of Bcl-2 and Bax levels) without altering the death receptor and endoplasmic reticulum-stress death pathways. Moreover, YXS reduced oxidative/nitrative stress (as reflected by decreased superoxide and nitrotyrosine content and normalized pro- and anti-oxidant enzyme levels). Interestingly, YXS upregulated endogenous nuclear receptors including LXRα, PPARα, PPARβ and ERα, and in-vivo knockdown of cardiac-specific LXRα significantly blunted the cardio-protective effects of YXS. Collectively, these data show that YXS is effective in mitigating MI/R injury by suppressing mitochondrial mediated apoptosis and oxidative stress and by upregulating LXRα, thereby providing a rationale for future clinical trials and clinical applications.

Antimalarial activity of medicinal plants from the Democratic Republic of Congo: A review

ETHNOPHARMACOLOGICAL RELEVANCE

Malaria is the most prevalent parasitic disease and the foremost cause of morbidity and mortality in the Democratic Republic of Congo. For the management of this disease, a large Congolese population recourses to traditional medicinal plants. To date the efficacy and safety of many of these plants have been validated scientifically in rodent malaria models. In order to generate scientific evidence of traditional remedies used in the Democratic Republic of Congo for the management of malaria, and show the potential of Congolese plants as a major source of antimalarial drugs, this review highlights the antiplasmodial and toxicological properties of the Congolese antimalarial plants investigated during the period of 1999-2014. In doing so, a useful resource for further complementary investigations is presented. Furthermore, this review may pave the way for the research and development of several available and affordable antimalarial phytomedicines.

MATERIALS AND METHODS

In order to get information on the different studies, a Google Scholar and PubMed literature search was performed using keywords (malaria, Congolese, medicinal plants, antiplasmodial/antimalarial activity, and toxicity). Data from non-indexed journals, Master and Doctoral dissertations were also collected.

RESULTS

Approximately 120 extracts and fractions obtained from Congolese medicinal plants showed pronounced or good antiplasmodial activity. A number of compounds with interesting antiplasmodial properties were also isolated and identified. Some of these compounds constituted new scaffolds for the synthesis of promising antimalarial drugs. Interestingly, most of these extracts and compounds possessed high selective activity against Plasmodium parasites compared to mammalian cells. The efficacy and safety of several plant-derived products was confirmed in mice, and a good correlation was observed between in vitro and in vivo antimalarial activity. The formulation of several plant-derived products also led to some clinical trials and license of three plant-derived drugs (Manalaria(®), Nsansiphos(®), and Quinine Pharmakina(®)).

CONCLUSION

The obtained results partly justify and support the use of various medicinal plants to treat malaria in folk medicine in the Democratic Republic of Congo. Antimalarial plants used in Congolese traditional medicine represent an important source for the discovery and development of new antimalarial agents. However, in order to ensure the integration of a larger number of plant-derived products in the Congolese healthcare system, some parameters and trends should be considered in further researches, in agreement with the objectives of the "Traditional Medicine Strategy" proposed by the World Health Organization in 2013. These include evaluation of geographical and seasonal variation, investigation of reproductive biology, assessment of prophylactic antimalarial activity, evaluation of natural products as adjuvant antioxidant therapy for malaria, development of plant-based combination therapies and monitoring of herbal medicines in pharmacovigilance systems.

Variations in key artemisinic and other metabolites throughout plant development in Artemisia annua L. for potential therapeutic use

Dried leaves of Artemisia annua show promise as an inexpensive and sustainable antimalarial therapeutic, especially for use in developing countries. Along with the potent terpene, artemisinin, many other small molecules produced by the plant seem to aid in the therapeutic response. However, little is known about the ontogenic and phenological production of artemisinin in the plant, and its plethora of other important secondary metabolites. From a consistently high artemisinin-producing A. annua clone (SAM) we extracted and analyzed by GC/MS 22 different metabolites including terpenes, flavonoids, a coumarin, and two phenolic acids as they varied during leaf development and growth of the plant from the vegetative stage through the reproductive, full flower stage. As leaves developed, the maximum amount of most metabolites was in the shoot apical meristem. Artemisinin, on the other hand, maximized once leaves matured. Leaf and apical tissues (e.g. buds, flowers) varied in their metabolite content with growth stage with maximum artemisinin and other important secondary metabolites determined to be at floral bud emergence. These results indicated that plants at the floral bud stage have the highest level of artemisinin and other therapeutic compounds for the treatment of malaria.