Antimalarial efficacy of a quantified extract of Nauclea pobeguinii stem bark in human adult volunteers with diagnosed uncomplicated falciparum malaria. Part 2: a clinical phase IIB trial.

According to the promising results of the Phase I and Phase IIA clinical trials with the herbal medicinal product PR 259 CT1 consisting of an 80 % ethanolic extract of the stem bark of Nauclea pobeguinii containing 5.6 % strictosamide, a Phase IIB study was conducted as a single blind prospective trial in 65 patients with proven Plasmodium falciparum malaria to evaluate the effectiveness and safety of this herbal drug. The study was carried out simultaneously using an artesunate-amodiaquine combination (Coarsucam®) as a positive control. This combination is the standard first-line treatment for uncomplicated malaria recommended by the National Programme of Malaria Control in the Democratic Republic of Congo (DR Congo). With regard to PR 259 CT1, patients were treated with a drug regimen of two 500-mg capsules three times daily for three days in the inpatient clinic, followed by out-patient treatment of one 500-mg capsule three times daily during the next four days; the positive control group received two tablets containing 100 mg artesunate and 270 mg amodiaquine (fixed-dose) once daily during three consecutive days. Antimalarial responses were evaluated according to the WHO 2003 guideline for a 14-day test. The results from the physical and laboratory examinations did not show any significant changes in values of vital signs, ECG, biochemical, and haematological parameters. The study showed a significant decreased parasitaemia in patients treated with PR 29 CT1 and artesunate-amodiaquine with adequate clinical parasitological responses (APCR) at day 14 of 87.9 and 96.9 %, respectively. The former product was better tolerated than the latter since more side effects were observed for the artesunate-amodiaquine combination. These results indicated that PR 259 CT1 can be considered as a promising candidate for the development of a herbal medicine for the treatment of uncomplicated falciparum malaria.

Antimalarial efficacy of a quantified extract of Nauclea pobeguinii stem bark in human adult volunteers with diagnosed uncomplicated falciparum malaria. Part 1: a clinical phase IIA trial.

The aim of this phase IIA clinical trial was to assess the efficacy of an 80 % ethanolic quantified extract (containing 5.6 % strictosamide as the putative active constituent) from Nauclea pobeguinii stem bark denoted as PR 259 CT1 in a small group of adult patients diagnosed with uncomplicated falciparum malaria. Results obtained from a phase I clinical trial on healthy male volunteers indicated that the oral administration during meals of two 500 mg capsules three times daily (each eight hours) during seven days was well tolerated and showed only mild and self-resolving adverse effects. This PR 259 CT1 drug regimen was obtained by mathematical conversion of animal doses obtained in several in vivo studies in mice to human equivalent doses as in falciparum malaria patients. The phase IIA study was an open cohort study in eleven appraisable adult patients suffering from proven Plasmodium falciparum malaria. The study was specifically designed to assess the efficacy of PR 259 CT1 administered with a dose regimen of two 500 mg capsules three times daily for three days, followed by outpatient treatment of one 500 mg capsule three times daily for the next four days, in order to prove that this therapeutic dose, which was calculated from animal doses, was effective to treat adult malaria patients and consequently useful for a future Phase IIB clinical trial. This study would then substitute a dose-escalating trial, which in general is used to find the appropriate dose for clinical studies. The phase IIA clinical trial was carried out according to the WHO 2003 14-day test, and the results revealed that all eleven patients were completely cleared of parasitemia and fever on days 3, 7, and 14 except for one patient, who experienced a recurrence of parasitemia at days 7 until 14. Besides this adequate clinical and parasitological response (ACPR), this trial also demonstrated that PR 259 CT1 was well tolerated with only mild and self-resolving adverse effects including fatigue and headache, which were in accordance with those found in the phase I clinical trial. Moreover, all symptoms progressively disappeared, and no symptoms were observed on day 14. Although the number of patients included in this study was rather limited, the statistical analysis nevertheless suggested the efficacy and tolerability of PR 259 CT1, which indicated that this herbal medicinal product might be considered as a putative candidate for a large scale clinical trial.

Assessment of the short-term safety and tolerability of a quantified 80 % ethanol extract from the stem bark of Nauclea pobeguinii (PR 259 CT1) in healthy volunteers: a clinical phase I study.

The aim of this study was to evaluate the short-term safety and tolerability of an antimalarial herbal medicinal product (PR 259 CT1) consisting of a quantified 80 % ethanol extract from the stem bark of Nauclea pobeguinii when given orally to healthy adult male volunteers. The amount of the major alkaloid strictosamide in the extract was determined by a validated HPLC method and was shown to be 5.6 %. The herbal preparation was formulated in a gelatine capsule form containing 500 mg of PCR 259 CT1. A sample of 15 healthy male volunteers, selected using the Lot Quality Assurance of Sampling (LQAS) method, was eligible for inclusion after fulfillment of the inclusion criteria and clinical examination by a physician. The volunteers were treated in an outpatient clinic with a drug regimen of two 500 mg capsules three times daily (each eight hours) for seven days, during meals. Safety and tolerability were monitored clinically, haematologically, biochemically and by electrocardiographic (ECG) examination at days 0, 1, 3, 7 and 14. Adverse effects were recorded by self-reporting of the participants or by detection of abnormalities in clinical examinations by a physician. The oral administration of PR 259 CT1 at high doses of 2 × 500 mg/capsule/day for 7 days was found to induce no significant changes in the concentration levels of all investigated haematological, biochemical, electrocardiogram and vital sign parameters and physical characteristics after 14 days of treatment compared to those seen in the baseline data. The concentration levels of all evaluated parameters were within the normal limits as reported in the literature. All adverse events noted were mild and self-resolving including increase of appetite (33 %), headache (20 %) and nausea (20 %). Other minor side effects were insomnia, somnolence and asthenia (7 %). Thus, PR 259 CT1 presented a significant safety and tolerability in healthy volunteers to allow its further development by starting a phase II clinical trial.

Antimalarial activity and toxicity evaluation of a quantified Nauclea pobeguinii extract.

AIM OF THE STUDY: To evaluate the in vitro and in vivo antiplasmodial activity and toxicity of the aqueous and 80% EtOH extract of the stem bark of Nauclea pobeguinii (Pob. Ex. Pell.) Petit (Rubiaceae), a plant used in traditional medicine in DR Congo against malaria. MATERIALS AND METHODS: The aqueous and 80% EtOH extract from N. pobeguinii stem bark, and its constituents (5S)-5-carboxystrictosidine, 19-O-methylangustoline, 3-O-beta-fucosylquinovic acid, 3-ketoquinovic acid and strictosamide, were evaluated for their in vitro activity against Plasmodium falciparum (chloroquine-sensitive Ghana-strain). The 80% EtOH extract, containing 5.6% strictosamide, was evaluated in vivo in the 4-day P. berghei mouse model, and in the P. yoelii N67 model. RESULTS: All compounds were inactive or only moderately active in vitro. The aqueous and 80% EtOH extract displayed moderate in vitro activity with IC(50) values of 44 and 32 microg/mL, respectively, without apparent cytotoxicity on MRC-5 cells (CC50>64 microg/mL). Daily oral dosing of the 80% EtOH extract, at 300 mg/kg, resulted in 86% reduction of parasitaemia in the 4-day P. berghei mouse model, and 75% reduction in the P. yoelii N67 model. Prolonging oral dosing to 2 x 5 days, with an interval of 2 days, and oral administration of the 80% EtOH extract at 300 mg/kg induced 92% reduction of parasitaemia, and a mean survival time of 17 days. Strictosamide, the putative active constituent, may be metabolically activated in the gastrointestinal tract after oral administration. Levels of creatinin, urea, ALAT and ASAT remained unchanged after treatment. No acute toxicity was observed in mice after a single 2g/kg oral dose, nor after 4 weekly doses. No significant macroscopic or microscopic lesions were observed in heart, lung, spleen, kidney, liver, large intestine and brain. CONCLUSIONS: These results can partly support and justify the use of N. pobeguinii in traditional medicine in the DR Congo for the treatment of uncomplicated malaria.

Antiamoebic activity of iridoids from Morinda morindoides leaves.

An aqueous decoction (dried extract), an 80 % methanolic extract from Morinda morindoides (Rubiaceae) leaves, and five iridoids isolated from the 80 % methanolic extract were evaluated in vitro for their activity against Entamoeba histolytica and their cytotoxicity. The aqueous decoction and the 80 % methanolic extract exhibited a promising antiamoebic activity with IC (50) values of 3.1 +/- 1.7 and 1.7 +/- 0.6 microg/mL, respectively. All tested iridoids displayed antiamoebic activity, the most active being epoxygaertneroside (IC (50): 1.3 +/- 0.4 microg/mL) and methoxygaertneroside (IC (50): 2.3 +/- 0.7 microg/mL) followed by gaertneroside, acetylgaertneroside and gaertneric acid with IC (50) values of 4.3 +/- 1.8, 5.4 +/- 1.4 and 7.1 +/- 1.4 microg/mL, respectively. Synergistic effects between the iridoids tested, or with other constituents, may explain the high activity of the extracts. All extracts and iridoids were devoid of any cytotoxic effect against MT-4 cells at the highest test concentration of 250 microg/mL. These findings support at least in part the traditional use of Morinda morindoides leaves for the treatment of amoebiasis in the Democratic Republic of Congo.