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Ethnopharmacological relevance: An aqueous decoction of root bark of Alstonia congensis Engl. (Apocynaceae) is used in several African countries to treat various ailments including malaria. Materials and methods: Extracts of different polarity and isolated constituents were tested in vitro for their antiplasmodial activity against the chloroquine-resistant strain Plasmodium falciparum K1 and the chloroquine-sensitive strain P. falciparum NF54A19A, as well as for their cytotoxic effects againt MRC-5 cells (human lung fibroblasts). Extracts and fractions were evaluated in vivo against the chloroquine-resistant strain P. yoelii N67 and the chloroquine-sensitive strain P. berghei berghei ANKA. Results: The aqueous extract, the 80% methanol extract and the alkaloid-enriched extract exhibited strong antiplasmodial activity against P. falciparum K1 with IC50 values < 10 mu g/ml and against P. falciparum NF54 A19A with IC50 values < 0.02 mu g/ml. In vivo against P. yoelii N67, at the highest oral dose of 400 mg/kg body weight, all extracts produced 70-73% chemosuppression, while against P. berghei berghei, more than 75% chemosuppression was observed. With regard to the isolated constituents, boonein was inactive in vitro against P. falci-parwn K-1 (IC50 > 64 mu M), while echitamine, 6,7-seco-angustilobine B and beta-amyrin exhibited moderate activity (IC50 < 30 mu M). Against P. falciparum NF54 A19A, boonein was inactive (IC50 > 64 mu M), while echitamine, 6,7-secoangustilobine and beta-amyrin showed moderate IC50 values of 11.07, 21.26 and 40.70 mu M, respectively. Conclusion: These results demonstrated that all extracts from A. congensis root bark possessed antiplasmodial activity in vitro and in vivo. They can be used as raw materials for the preparation of ameliorated remedies for the treatment of uncomplicated malaria. The observed antiplasmodial activity may be due in part to the presence of indole alkaloids.

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.

The seed oil of Adenanthera pavonina L. (Fabaceaea) collected in Kinshasa, Democratic Republic of Congo was analyzed for its proximate, lipids, mineral fatty acid and amino acid profiles, carbohydrate, mineral elements starch and fiber compositions. The mean values of various nutrients for proximate composition (%) were: moisture 7.36  1.08%, crude proteins 31.04  2.30, crude lipids or fats 11.03  1.41, total fiber dietary 7.84  0.04, carbohydrates 52.04  1.06, starch 41.13 1.04. The calculated energy was 1953.60 kJ/100 g. These results indicated that the studied oil contained higher amounts of proteins, lipids, carbohydrates, ash, and starch compared with most of the commonly consumed legumes or seeds. Mineral elements (mg/100g) included: sodium (842.30), potassium (1284.22, iron (11.71, aluminium (9.65) and magnesium (4.63).The fatty acid profile revealed that linoleic acid was the most abundant fatty acid (52.6%) followed by oleic acid (18.7%), palmitic acid 7.5%) and gadolic acid (7.3%). The seed proteins of this oil contained higher levels of the essential amino acids such as arginine, leucine, lysine, phenylalanine and valine (4.5 to 11.5%) and non-essential amino acid such as glutamic acid, aspartic acid, glycine, proline and serine (4 to 23%). The comparison of these parameters with known oils showed that A. pavonina oil, to some extent, resembles oils that are processed for food and could be serve as a source of good edible oil for human and animal.

The aqueous extracts, the ethanol extracts and their respective fractions of the seeds from ripe and unripe fruits of Carica papaya were screened for their putative antibacterial, antiamoebic and antispasmodic activities. Results indicate that the aqueous extracts, the ethanol extracts and their respective fractions from the seeds of both states of the fruit exhibited antibacterial activity at different extents. Samples of the seeds from ripe fruits showed higher activity with minimum inhibitory and minimum bactericidal concentrations ranged from 7.81 to 250 μg/ml compared to samples from the seeds of unripe fruits (15.62 to 500 μg/ml) against the majority of selected bacteria. The evaluation of the antiamoebic activity against Entamoeba histolytica revealed that the aqueous extracts, the ethanol extracts and their fractions of seeds from ripe and unripe fruits were able to inhibit the growth of this parasite with minimum amoebicidal concentrations (MAC) less than 20 μg/ml. A significant and gradual decrease of vital parasites in the presence of all tested samples was daily observed from Day 1 to Day 6 while in negative control tubes, a significant increase was recorded. The most active samples were the aqueous, ethanol and total alkaloid extracts from the seeds of ripe fruits with 1 < MAC (minimal amoebicidal concentration) < 5 μg/ml and the ethanol extract from the seeds of unripe fruits with MAC value of 3.12 μg/ml. In antispasmodic activity testing, the aqueous extracts, the ethanol extracts and their respective fractions from both seed fruits state produced more than 60% inhibition of contractions of guinea-pig ileum induced by acetylcholine and depolarized solution rich in KCl at the tested concentration of 40 μg/ml. The most active samples were the aqueous and alkaloid extracts, and ethanol extracts from both seeds states showing more than 70% and 80% inhibition respectively, the ethylacetate fraction from the partition of the ethanol extract of seeds from ripe fruits producing more than 70% inhibition of contractions of guinea pig-ileum induced by both agonists while the same fraction of the seeds from unripe fruits produced more than 65% inhibition, but less than 70%. These reported results can justify and support the use of mainly the seeds from the ripe fruits of C. papaya in traditional medicine for the treating of diarrhea since they would act by their antibacterial, antiamoebic and spasmolytic activities proven in the present study.