Bioavailability of the Antimalarial Drug Artemisinin Delivered Orally as Dried Leaves of Artemisia annua: the Role of Solubility and Protein.

Malaria treatment using orally consumed dried leaves of the artemisinin producing GRAS plant Artemisia annua has recently shown promise. Previously we showed, oral consumption of A. annua dried leaves (DLA) yielded \u3e40 times more artemisinin in the blood of mice than treatment with pure artemisinin. Using the Caco-2 cell culture model of the human intestinal epithelium, we also showed that compared to pure artemisinin, digested DLA doubled the permeability (Papp). Here, using simulated human digestion, we show that artemisinin solubility is about seven times higher in digestates of DLA than in digestates of pure artemisinin, likely contributing to its enhanced bioavailability. Digestion with pure artemisinin combined with levels of essential oils comparable to that in DLA increased the solubility of artemisinin 2.5 times indicating essential oils play a role in increasing artemisinin solubility. Interestingly, increasing the starting concentration of artemisinin in Caco-2 transport studies did not alter Papp. Considering malaria affects mostly young children and about 60% of the population experiences DLA as unpleasant tasting, we also tested several protein rich foods as potential flavor-masking agents for their effects on bioavailability. We showed that while taste was masked, peanuts and a peanut-based paste used to treat malnutrition, PlumpyNut, reduced artemisinin and flavonoid levels in simulated digestates, respectively, likely decreasing their bioavailability. Experiments to further investigate the role of several compounds such as camphor, a principle component of the essential oil fraction, and flavonoids on artemisinin solubility and bioavailability are ongoing. The results of these experiments are helping to explain the increased bioavailability afforded by DLA seen in mice

The Therapeutic Effects of per os Artemisinin Delivered as Dried Leaf Artemisia annuavs. Artesunate in Non-small Cell Lung Cancer

Artemisinin, the active component of Artemisia annua L. used to treat malaria, also has therapeutic efficacy against many types of cancer. Solubility issues led to development of more soluble semi-synthetic derivatives. Artesunate (ART), in particular, is a more soluble derivative of artemisinin and has profound cytotoxicity toward many types of tumor cells, but healthy cells are less sensitive. Artemisinin delivered per os as dried leaves, referred to as dried leaf artemisinin (DLA), was shown in rodent studies to improve bioavailability by more than 40-fold. ART has been widely studied for its anti-cancer properties, but it has yet to be shown if DLA also improves therapeutic efficacy. As A. annua produces a wide array of phytochemicals with anti-cancer activity other than artemisinin, it is reasonable to expect DLA may provide a more potent therapeutic. Using two non-small cell lung cancer cell lines, PC-9 and H1299, artemisinin delivered as DLA effectively reduced viability with 24h IC50 values of 56.3 and 77.5 µM for PC-9 and H1299, respectively, as determined by MTT assay. For PC-9 cells, this was a 2.5-fold improvement in the 24h IC50 value for ART at 142.9 µM. However, for the H1299 cells, ART at 60.6 µM was better than DLA by about 25%. Ongoing studies are comparing the mechanism of action of DLA and ART on these two cell lines and will analyze markers for apoptosis, proliferation and metastatic migration and invasion. Xenograft models also will be used to compare in vivo efficacy of DLA and ART on tumor reduction. These studies will help us further understand the anti-cancer effects of artemisinin when delivered per os as dried plant leaves

Use of whole plant Artemisia annua L. as an antimalarial therapy

Anti-malarial drugs are primary weapons for reducing Plasmodium transmission in human populations. Successful drugs have been highly efficacious and inexpensive to synthetically manufacture. Emergence of resistant parasites reduces the lifespan of each drug that is developed and deployed. Currently, the most effective anti-malarial is artemisinin (AN), which is extracted from the leaves of Artemisia annua. Because of its poor pharmacokinetic properties and prudent efforts to curtail emergence of resistance, AN is prescribed only in combination with other anti-malarials composing an Artemisinin Combination Therapy (ACT). Low yield in the plant and the added cost of secondary anti-malarials in the ACT, make AN in the developing world a costly treatment. Here we show that dried leaves of A. annua administered orally are more effective at killing malaria parasites than a comparable dose of purified drug in a rodent malaria model (P. chabaudi). A single dose of whole plant (WP) A. annua containing 24 mg/kg AN clears 99% of parasites, where a comparable dose of pure drug has half that effect. This is consistent with findings that blood levels of AN are 40 times greater in mice receiving WP versus those given pure drug. We hypothesize that in addition to increasing bioavailability of AN, administration of WP alone may constitute a combination therapy because it contains other anti-malarial compounds that have been shown to synergize with AN. Inexpensive, efficacious, and resilient treatment for malaria based upon WP A. annua that can be grown and processed locally would be an effective addition to the global effort to reduce malaria morbidity and mortality

Developing a Whole Plant Artemisia annua Antimalarial Therapeutic: pACT

The GRAS plant Artemisia annua L. produces the sesquiterpene lactone, artemisinin. The current therapy for malaria is artemisinin + an older drug: artemisinin combination therapy (ACT). In Plasmodium chabaudi-infected mice, dried leaves of A. annua are more potent than equal amounts of pure artemisinin and may also prevent artemisinin drug resistance from emerging. This whole plant therapy is pACT: plant-based artemisinin combination therapy. Pharmacokinetics in healthy and infected mice given either pure artemisinin or pACT is different and showed that \u3e 40 fold more artemisinin enters the blood when plant material is present; plant matrix enhanced bioavailability into serum. Dried leaves as capsules or tablets given to African malaria patients were also efficacious. Flavonoids, phenolic acids, monoterpenes and other artemisinic metabolites found in the plant have mild antimalarial activity. Some may synergize with artemisinin to enhance its efficacy. In simulated digestion studies the effects of cellulose and gelatin capsules, sucrose, 4 oils, and 3 staple grains (rice, corn, and millet) were studied to determine their effect on AN and flavonoid release into the liquid phase of the intestinal stage of digestion. Compared to pACT alone: sucrose and oil enhanced release of flavonoids by 100%, but artemisinin was unaffected; both capsule types, and corn and millet meal significantly reduced artemisinin release, but had no effect on flavonoids. From field trials in MA, it was estimated that \u3e 500,000 patients could be treated from plants grown on 1 ac of land. Analysis of 10 crops of the high artemisinin-producing WPI clone of A. annua grown under different field and lab conditions showed there was consistent production of artemisinin at about 1.4% DW. Together these results show how a simple herbal remedy could be used as an efficacious, inexpensive, controlled and sustainable orally delivered therapeutic for treating malaria and other artemisinin-susceptible diseases