Anti-plasmodial and anti-inflammatory activities of cyclotide-rich extract and fraction of Oldenlandia affinis (R. & S.) D.C. (Rubiaceae).

BACKGROUND: Oldenlandia affinis, commonly called 'kalata-kalata', a versatile plant used locally to treat malaria fever in some parts of sub-Saharan Africa was investigated for anti-plasmodial and anti-inflammatory activities. OBJECTIVE: The study was designed to evaluate the antiplasmodial as well as anti-inflammatory activities of whole extract and cyclotide-rich fraction of Oldenlandia affinis. METHOD: The dichloromethane-methanol extract (ODE) of the plant, O. affinis was investigated for suppressive and curative antiplasmodial activities against Plasmodium berghei in mice. ODE and the cyclotide-rich fraction (CRF) was investigated for chronic and acute anti-inflammatory activities in rat models of inflammation. Inhibition of pro-inflammatory mediators was studied in RAW264.7 macrophages. RESULTS: ODE exhibited significant (p<0.05) reduction in mean parasitaemia in both the suppressive and curative models of Plasmodium berghei infection in mice.Administration of ODE(100, 200, or 400 mg/kg) and CRF (100, 200, or 400 mg/kg) produced significant inhibition of rodent models of acute and chronic inflammation . This observation is supported by the significant (P<0.05) inhibition of pro-inflammatory mediators, inducible nitric oxide (iNO) and tumour necrosis factor-alpha (TNF-α), and the reactive radical scavenging activities in RAW264.7 macrophages. CONCLUSION: These findings could explain, at least in part, the successes reported in the use of the herb, Oldenlandia affinis in the traditional treatment of malaria fever.

Landolphia owariensis leaf extracts reduce parasitemia in Plasmodium berghei-infected mice.

Context Landolphia owariensis P. Beauv. (Apocyanaceae) leaf is used in southeast Nigeria to treat malaria. Objective This study evaluated the antiplasmodial activity of L. owariensis leaf extract and fractions, also the phytoconstituents were standardized and analyzed. Methods The effects of daily, oral administrations of 200, 400 and 800 mg/kg of L. owariensis leaf extract (LOE), its hexane (LOHF), ethyl acetate (LOEF) and methanol (LOMF) fractions on early, established and residual infections in Plasmodium berghei-infected albino mice were evaluated in vivo. The extract and fractions were subjected to phytochemical analysis and HPLC fingerprinting, and the acute toxicity of LOE was evaluated. Results The extract and fractions elicited 29-86, 18-95 and 75-96% significant (p < 0.001) suppression of parasitemia in early, established and residual infections, respectively. The ED50 values for suppressive activity of LOE, LOHF, LOEF and LOMF were 266.56, 514.93, 392.95 and 165.70 mg/kg, respectively. The post-day 30-survival index was 16.7-50, 16.7, 16.7-66.7 and 50-83.3% for LOE, LOHF, LOEF, and LOMF, respectively. Extract-treated mice significantly (p < 0.001) gained weight and had reduced mortality compared with negative control (untreated) mice. An oral LD50 value >5000 mg/kg in mice was established for LOE. The LOMF showed the greatest antiplasmodial activity in all the models, suggesting that the antimalarial activity of the plant may be attributed to alkaloids, flavonoids, saponins and tannins present in the fraction. Conclusion Results demonstrate the antiplasmodial activity of L. owariensis leaf, and provide a pharmacological rationale for its ethnomedicinal use as an antimalarial agent.

Extracts of Leptadenia hastata Leaf, a Famine Food and Traditional Remedy for Furuncles, Suppress Inflammation in Murine Models.

The effects of the methanol extract (LHE), hexane (LHHF), ethylacetate (LHEF) and methanol (LHMF) fractions of leaf of Leptadenia hastata on acute and chronic inflammation were studied. Furthermore, the effects of LHE on acetic acid induced increase in vascular permeability, carrageenan induced leucocyte migration and membrane stability were evaluated. The LHE and fractions were also subjected to phytochemical analysis. The LHE, LHEF and LHMF significantly (p < 0.05) suppressed topical ear edema, systemic paw edema, global edematous response to formaldehyde arthritis and granuloma tissue growth. The LHE suppressed acetic acid induced vascular permeability and carrageenan-induced leucocyte migration, and also stabilized the erythrocyte membrane. An acute toxicity test in mice established an oral LD50 > 5 g/kg for LHE. The LHEF elicited the greatest inhibition, suggesting that the observed anti-inflammatory effects may be attributable to the flavonoids abundant in the fraction. These findings demonstrate that the effectiveness of L. hastata leaf in the treatment of furuncles may largely derive from anti-inflammatory activities mediated through inhibition of both increase in vascular permeability and leucocyte migration, and stabilization of cell membranes.

Antimicrobial Effects of a Lipophilic Fraction and Kaurenoic Acid Isolated from the Root Bark Extracts of Annona senegalensis.

Root bark preparation of Annona senegalensis Pers. (Annonaceae) is used in Nigerian ethnomedicine for treatment of infectious diseases. Extraction of the A. senegalensis powdered root bark with methanol-methylene chloride (1 : 1) mixture yielded the methanol-methylene extract (MME) which was fractionated to obtain the ethyl acetate fraction (EF). The EF on further fractionation gave two active subfractions, F1 and F2. The F1 yielded a lipophilic oily liquid while F2 on purification, precipitated white crystalline compound, AS2. F1 was analyzed using GC-MS, while AS2 was characterized by proton NMR and X-ray crystallography. Antibacterial and antifungal studies were performed using agar-well-diffusion method with 0.5 McFarland standard and MICs calculated. GC-MS gave 6 major constituents: kaur-16-en-19-oic acid; 1-dodecanol; 1-naphthalenemethanol; 6,6-dimethyl-bicyclo[3.1.1]hept-2-ene-2-ethanol; 3,3-dimethyl-2-(3-methylbuta-1,3-dienyl)cyclohexane-1-methanol; 3-hydroxyandrostan-17-carboxylic acid. AS2 was found to be kaur-16-en-19-oic acid. The MICs of EF, F1, and AS2 against B. subtilis were 180, 60, and 30 µg/mL, respectively. AS2 exhibited activity against S. aureus with an MIC of 150 µg/mL, while F1 was active against P. aeruginosa with an MIC of 40 µg/mL. However, the extracts and AS2 exhibited no effects against Candida albicans and Aspergillus niger. Therefore, kaurenoic acid and the lipophilic fraction from A. senegalensis root bark exhibited potent antibacterial activity.

Studies on the antiulcer and gastrointestinal effects of stem bark extract of Bridelia ferruginea.

The antiulcer and gastrointestinal effects of methanol stem bark extract (BFME) of Bridelia ferruginea Benth. (Euphorbiaceae) and its solvent fractions-dichloromethane (DCMF) and methanol (MF)-were studied using indomethacin- and ethanol-induced ulcers in rats, small intestinal transit of charcoal meal in mice, and the effects on acetylcholine-induced contractions of the isolated guinea pig ileum. The extract and fractions significantly (P<0.05) protected the rats against ethanol and indomethacin-induced ulcers and inhibited small intestinal propulsion in the order of magnitude: DCMF>MF>BFME. On the guinea pig ileum, MF (0.05 - 6.40 mg/ml) elicited no inhibition, DCMF (5 - 40 µg/ml) antagonized acetylcholine-induced contractions of the guinea pig ileum with IC50 of 10.47µg/ml, while BFME (0.05 - 12.80 mg/ml) contracted the guinea pig ileum with EC50 of 1 mg/ml. Oral LD50 of BFME in mice was estimated to be 2,154 mg/kg. Phytochemistry tests revealed the presence of tannins, saponins, steroids, terpenoids, flavonoids and resins in BFME, MF tested positive for tannins, saponins, steroids, terpenoids, and flavonoids, while DCMF gave positive reactions for flavonoids, steroids, terpenoids and resins. These findings suggest that constituents of the stem bark of B. ferruginea possess antiulcer properties. In addition, some non-polar constituents possess spasmolytic activity while spasmogenic activity is likely associated with some polar constituents.