S.V. Nwafor’s research while affiliated with University of Nigeria and other places

The study was undertaken to investigate the antiulcer properties of the ethanol root extract of Cissampelos mucronata. A. Rich (Menispermaceae). Three models of experimental ulcer induction in rats were employed in the study. Oral median lethal dose (LD50) was determined in mice using Lorke's method, and the isolated tissue preparations were used to investigate the effect of the extract on calcium ion mobilization in the ileum and H2-receptor blocking property in nongravid rat uterine strip. Study of the acute toxicity test indicated an LD50 of 288.53 mg/kg. Antiulcer study showed that the extract exhibited dose-dependent antiulcer properties in the order indomethacin > histamine > stress-induced ulcers. The ulcer index recorded for the extract against ulcer induced by indomethacin and histamine were significant at p < 0.05. In vitro. pharmacological studies indicated that the extract possessed ability to block the voltage-gated calcium channels; nevertheless, it did not antagonize histamine-induced relaxation of the rat uterine smooth muscle. The results indicate that the ethanol root extract of C. mucronata. exhibited antiulcer property especially against indomethacin-induced ulcer. Cytoprotection and antispasmodic mechanisms of action may be responsible for the antiulcer properties.

The aqueous leaf extract of Viscum album Stapf (Loranthaceae) given i.p. produced a dose-dependent fall in blood sugar. Doses of 200 mg/kg and 400 mg/kg body weight produced significant (p < 0.05) lowering of blood sugar in fasted normal white albino rats and alloxanized rabbits respectively. The fasting blood sugar, measured in milligram per 100ml (mg%), in normoglycemic rats was reduced by 30.06% while in alloxanized rabbits, the blood sugar was reduced from mean value of 650 ± 7.2mg % at zero hour to 87 ± 8.2mg% at 4h. The hypoglycemic effects were compared with those of tolbutamide. Acute toxicity studies of the extract in mice gave LD 50 value of 4.18 ± 0.96 g/kg body weight when given i.p. The mechanism underlying the observed hypoglycemic effect of V. album extract is not fully understood but may be related to enhancement in peripheral utilization of glucose and increase in insulin secretion.

A methanol extract and fractions (pet ether and methanol) of Aframomum melegueta K. Schum (Zingiberacea) seeds were evaluated for anti-inflammatory activity. An acute toxicity test in mice was used to establish an i.p. LD50 of 2154 mg/kg for the methanol extract. The methanol extract and the pet ether fraction (oil) significantly (P < 0.05) inhibited xylene-induced topical edema in the mouse ear. In contrast, the methanol soluble fraction exhibited no topical anti-inflammatory activity. The methanol extract and the pet ether and methanol fractions had systemic anti-inflammatory activity, significantly (P < 0.05) inhibiting rat paw edema induced by egg albumin. An ulcerogenic assay in rats revealed zero ulcer incidence for the methanol extract and the pet ether and methanol fractions, suggesting a possible non-inhibition of prostaglandin synthesis. Phytochemical analysis of the methanol extract revealed the presence of alkaloids, glycosides, tannins, flavonoids, sterols, triterpenes, and oils, while the methanol fraction contained alkaloids, glycosides, tannins, flavonoids, sterols, and resins. The study results indicate that seeds of Aframomum melegueta possess potent anti-inflammatory activity with a favorable gastric tolerability profile.

The anti-inflammatory activity of hexane leaf extract of Aspilia africana C.D. Adams (Compositae) was evaluated in rodents using the xylene-induced ear edema, egg albumin- and agar-induced paw edema, formaldehyde-induced arthritis, cotton pellet granuloma, gastric ulcerogenic, acetic acid-induced vascular permeability and dextran-induced in vivo leukocyte migration tests. Results showed that the extract (5mg/ear) inhibited topical edema in the mouse ear and at 200 and 400mg/kg (i.p.), it significantly (P<0.05) suppressed the development of egg albumin- and agar-induced paw edema, and the global edematous response to arthritis induced by formaldehyde in rats. Oral administration of the extract (200 or 400mg/kg) evoked a significant (P<0.05) dose-related ulceration of the rat gastric mucosa and inhibition of vascular permeability induced by acetic acid in mice. The extract also significantly (P<0.05) reduced total leukocyte and neutrophils counts in a non-dose-related manner. However, it significantly (P<0.05) increased lymphocyte counts and stimulated the growth of granuloma tissues induced by subcutaneously implanted cotton pellets in rats. Phytochemical tests showed that the extract contained sterols and terpenoids. These findings suggest that the leaves of Aspilia africana possess anti-inflammatory activity in acute and certain aspects of chronic inflammation, which may derive from inhibition of prostaglandins synthesis, inhibition of increased vascular permeability, inhibition of neutrophil migration into inflamed tissues, and stimulation of lymphocyte accumulation, which may enhance tissue repair and healing. The terpenoids present in the leaves may account for the anti-inflammatory activity.

The leaf of Asystasia gangetica T. Adams (Acanthaceae) is used in many parts of Nigeria for the management of asthma. This study was aimed at investigating the anti-asthmatic property of hexane, ethylacetate, and methanol extracts of the leaves of Asystasia gangetica, obtained by successive sohxlet extraction. The results indicated that the extracts did not exhibit contractile or relaxant activity in isolated tissue preparations; however, they inhibited the contraction evoked by spasmogens; the IC(50) were calculated, where possible. The extracts relaxed histamine-precontracted tracheal strips in the following degree of potency-ethylacetate extract>hexane extract=methanol extract. The extracts also exhibited anti-inflammatory activity in the order of magnitude-methanol extract>hexane extract>ethylacetate extract. Acute toxicity test estimated an i.p. LD(50) of 2150 mg/kg in mice for methanol extract while phytochemical screening showed the presence of carbohydrates, proteins, alkaloids, tannins, steroidal aglycones, saponins, flavonoids, reducing sugars, and triterpenoids, with the methanol extract having the highest number of constituents. The study justified the use of the leaf of Asystasia gangetica in the management of asthma in Nigerian folk medicine.

Five fractions (F1-F5) isolated from the methanolic leaf extract of Cissampelos mucronata A. Rich were investigated for antiulcer activity. At the dose of 450 mg/kg, they showed varying degree of protection against ulcer induced by indomethacin; the order of protection being F1>F4>F5>F2>F3. The antiulcer potency of F1 and F2 is comparable with that of cimetidine (100 mg/kg, i.p.). Inhibition of gastric mucosal damage may partly contribute to the antiulcer activity of the fractions.

As a result of the inherent problems associated with the current anti-inflammatory agents, there is continuous search especially from natural sources for alternative agents. A good number of plants are employed in the treatment of inflammatory disorders by natural healers. Some of these plants include Aloe vera, Consolida regalis, Chasmanthera dependens, Culcasia scandens, Crataeva religiosa, Tanacetum vulgare, Holmskioldia sanguinea, Mitracarpus scaber, Turner ulmifolia, etc. Most of these plants have demonstrated varying activities in the various in vivo and in vitro inflammatory models. The potency of these plants is attributed to several active principles present in them, which may act at any of the multiple targets in the inflammatory response pathway. In addition to anti-inflammatory activity, some of these plants also possess beneficial properties such as antimicrobial, analgesic, antipyretic and antiulcer effects. These additional effects complement the inherent anti-inflammatory activity and may confer advantage on these plants. Some active anti-inflammatory principles of these plants have been identified, isolated and characterized. They include - lupeol, premnazole, (+) - usnic acid, (+) - pinitol, zanhasaponins A and B, sasanquol, parthenolide etc. These compounds could provide drugs with comparative advantage over existing agents and may as well serve as leads for further development into more active drugs with lesser adverse effects. This review discusses some of these plants with putative anti-inflammatory properties.

Bacterial infections often co-exist with acute malarial attacks. The effect of combining arthemeter (a new antimalarial) with some commonly used 4-quinolones (ciprofloxacin, pefloxacin, norfloxacin and nalidixic acid) was investigated in-vitro with a view to providing data for the design of drug regimens for the treatment of such infections. While arthemeter demonstrated no antibacterial activity whatsoever against any of the test microorganisms (E. coli and Staph. aereus), the 4-quinolones shared marked activity. Comparative analyses of the activity of each quinolone alone and in combination with arthemeter showed 0% 43.8%, 44.9% and -12.2% change in the minimum inhibitory concentration (MIC) of nalidixic acid pefloxacin, ciprofloxacin and norfloxacin respectively against E. coli and -17.5%, 22.3% 35.8% and 50.9% change in the MICs of the same respective drugs against Staph. aureus. These changes in MIC were statistically significant (Pf0.05). With respect to infections caused by E. coli and E. coli, the combination of artemether with ciprofloxacin or pefloxacin proves to be a rational chemotherapeutic regimen when such infection co-exist with malaria.

The present study compares the adsorptive potential of Garcinia kola (Guttiferae) seed (GKS) for ciprofloxacin hydrochloride (CIP) with that of a standard adsorbent and a general poison antidote, activated charcoal (AC), using an in vitro design. In unbuffered medium (distilled water), the adsorption isotherms were shown to follow the classical Langmuir type 1 isotherm. GKS showed a higher adsorptive capacity for CIP than AC. Increased ionic strength generally decreased the adsorptive potentials of both adsorbents. Optimum ciprofloxacin adsorption occurred at pH 7 even though a clinically significant quantity (above 60%) was adsorbed by both adsorbents at all the tested pH ranges. While AC may be adsorbing CIP exclusively through surface accumulation and ion exchange, a combination of complexation and ion exchange may be responsible for the GKS-CIP interaction. We bring to limelight the potential usefulness of the GKS as an alternative antidote in the management of poisoning caused by ciprofloxacin. Hence, attention is drawn to the fact that concurrent intake of GKS and ciprofloxacin should be contraindicated because of the possibility of greatly impairing the drug's bioavailability.