α-Glucosidase Inhibitory Prenylated Anthranols from Harungana madagascariensis

Four new prenylated anthranols, harunganols C-F (1-4), along with kenganthranol A (5), harunganin (6), and ferruginin A (7), were identified from the leaves of Harungana madagascariensis. The structures of compounds 2, 5, and 7 were confirmed by single-crystal X-ray diffraction analysis. Compound 1 is a unique symmetrical anthranol dimer connected via a CH2 group. Compound 4 possesses a unique C-10 hemiketal group. All anthranols were evaluated for their α-glucosidase inhibitory activities. They displayed a higher potency compared to acarbose except for 3 and 4. In particular, harunganol C (1) showed an IC50 value of 1.2 μM.

Anti-cancerous triterpenoid saponins from Lecaniodiscus cupanioides

From the ethanol extract of the stem of Lecaniodiscus cupanioides Planch, two known compounds 1 and 2 were isolated and identified as triterpenoid saponins 3-O-[α-L-arabinofuranosyl- (1→3)-α-L-rhamnopyranosyl- (1→2)-α-L-arabinopyranosyl-]-hederagenin and 3-O- [α-L-arabinopyranosyl- (1→3)-α-L-rhamnopyranosyl (1→2)-α-L-arabinopyranosyl-]-hederagenin. The structures were established by physicochemical and spectroscopic investigations (MS and NMR) as well as comparison of literature data. The compound 1 exhibited anticancer activity against human colon carcinoma H-116, human lung carcinoma A-549 and human lung carcinoma HT-29 cell lines with IC₅₀ 5.0, 2.5 and 2.5μg/ml respectively and compound 2 exhibited similar activities with IC₅₀5.0, 5.0 and 2.5μg/ml respectively. This suggests that the isolated triterpenoid saponins may be considered as potential anticancer leads for further studies.

Traditional medicinal plants in Nigeria--remedies or risks

ETHNO-PHARMACOLOGICAL RELEVANCE

Soil pollution due to increasing industrialization is a reality that is taking its toll on mankind today. Considering the population of people that use herbal remedies especially in developing countries and the discharge of industrial waste on surrounding herbal vegetation, it is imperative to determine the heavy metals contamination in some commonly used medicinal plants.

MATERIALS AND METHODS

Representative samples of five medicinal plants Ageratum conyzoides, Aspilia africana, Alchornea cordifolia, Amaranthus brasiliensis and Chromolaena odorata were collected from Ikpoba-Okha L.G.A, Edo State Nigeria, around a paint company and another set of same plants were collected from a non-polluted source. Dried leaves and roots of collected plants were digested and analyzed using Atomic Absorption Spectrophotometer (AAS) for the presence of Lead (Pb), Cadmium (Cd), Chromium (Cr), Nickel (Ni) and Zinc (Zn). Soil samples from polluted and non-polluted areas were also analyzed to ascertain the levels of these heavy metals in the environment.

RESULTS

Results show that the concentrations of these heavy metals in the leaves and roots of plants collected from polluted soil were significantly higher than those obtained from unpolluted soil. Correspondingly heavy metal concentrations were significantly higher in polluted than in unpolluted soil samples.

CONCLUSION

As part of continuing effort in the standardization of traditional remedies, environmental contamination control and abatement is evident. The source of medicinal plants/herbs should also be a cause for concern since the toxicity of medicinal plants is sometimes associated with environmental sources of the plants.

Evaluation of antioxidant activity of Tetracarpidium conophorum (Müll. Arg) Hutch & Dalziel leaves

This study evaluated the antioxidant activity as well as bioflavonoid content of the methanol and ethanol-water extracts of the fresh and dried leaves of Tetracarpidium conophorum. Antioxidant activity was determined by spectrophotometric methods using DPPH free radical, nitric oxide radical inhibition and ferric reducing antioxidant power assays. In addition, total phenolics, flavonoids and proanthocyanidin content were also determined. The ethanol: water extract of the dried leaves had the highest antioxidant activity with a 50% inhibition of DPPH at a concentration of 0.017 mg/mL compared to the standards, Vitamin C and Vitamin E with inhibition of 0.019 and 0.011 mg/mL, respectively. This extract also showed nitric oxide radical inhibition activity comparable to that of rutin, 54.45% and 55.03% for extract and rutin, respectively, at 0.1 mg/mL. Ferric reducing power was also comparable to that of ascorbic acid (281 and 287 μM Fe (11)/g, resp.) at a concentration of 1 mg/mL. The methanol extract of both the dried and the fresh leaves had higher phenolic, flavonoids and proanthocyanidin content than the ethanol:water extract. The study reveals that T. conophorum can be an interesting source of antioxidants with their potential use in different fields namely food, cosmetics and pharmaceuticals.

Pesticide residue levels in maize samples from markets in Lagos State, Nigeria

BACKGROUND

Pesticides are used widely in agriculture to control destructive pests and hence increase food supply. Their use inadvertently leads to residues in food crops and the environment. Pesticides, by nature are poisonous and exposure of humans to their residues may cause health hazards which include neurotoxicity and carcinogenicity among others. Evaluation of pesticide residues in food is therefore of public health importance and would help to ensure that levels are kept within safety limits.

OBJECTIVE

The aim of this study was to determine the incidence and quantity of organochlorine pesticide residues in maize samples collected from various markets in Lagos State and compare values obtained with established safety values in order to highlight possible health hazards.

METHODS

In this study, samples of white maize (Zea mays L.) purchased from different markets in Lagos State were analyzed for residues of organochlorine pesticides using gas chromatograph with mass spectrometric detector (GC-MS) after careful extraction and cleanup.

RESULTS

The results showed that 96% of the maize samples contained residues of one or more organochlorine pesticides. Mean concentrations ranged from 7.9-52.0 microg/kg and maximum residue limits (MRLs) of some pesticides were exceeded in up to 7% of samples. The estimated total diet intakes (ETDIs) for aldrin and dieldrin exceeded their maximum permissible intakes.

CONCLUSION

It is concluded that residues of organochlorine pesticides are present in maize in Lagos markets. Some exceed safety levels with possible adverse effects on human health. There is therefore a need for more stringent monitoring of the use of pesticides in agriculture and food storage in Nigeria.

Comparative dissolution profiles of representative quinolones in different media

BACKGROUND

Quinolones have a broad spectrum of activity against bacteria and are a class of synthetic antimicrobial modeled after nalidixic acid.

OBJECTIVE

To determine the dissolution efficiencies of ciprofloxacin and sparfloxacin in 0.1NHCL, deionized water, 0.1 M acetic acid and pH 7.4 phosphate buffer.

METHODS

The in-vitro dissolution profiles of ciprofloxacin (250 mg and 500 mg) and sparfloxacin (200 mg) tablets were studied in the respective media using US Pharmacopoeia (USP) Apparatus II. In order to monitor the comparative rate of dissolution, samples were withdrawn from the medium for quantification over nine pre-determined time points during a total period of two hours. Samples were analyzed by an HPLC method capable of concurrent elution of ciprofloxacin/sparfloxacin.

RESULTS

The medium with most stable release pattern for the representative quinolones was 0.1M acetic acid, followed by 0.1NHCl, distilled water and pH 7.4 buffer respectively. The %Q30 of Ciprofloxacin(CP) and Sparfloxacin(SP) was found to conform entirely to both USP2004 and FDA specifications. Sparfloxacin was found to be unstable due to cloudiness observed in 0.1N HCl medium. The CP and SP showed highest %Q(max) in 0.1M acetic acid compared to other media. This result has implication in the choice of medium for dissolution testing of quinolones, particularly for comparative purposes in the absence of specific monograph recommendations. Furthermore, it supports the change from 0.1N to 0.01NHCI for ciprofloxacin in the USP as a monographic modification.

CONCLUSION

We conclude that there is a need to have a general-purpose dissolution medium for comparing profiles of different quinolones, 0.1M acetic acid may be a suitable candidate. Furthermore, the study may serve as guidance to the drug regulatory authorities in formulation of monographs for the drugs.

Artesunate causes relaxation of rat aortic rings and reduces the contractile response to noradrenaline

OBJECTIVE

To study if the present widely used artemisin derived anti-malaria drugs have vascular effects.

METHODS

Aortic rings were obtained from adult male Sprague-Dawley rats. The rings were mounted in an organ bath and tension recorded using isometric force transducers. After pre-contraction with noradrenaline, cumulative doses of artesunate were added to the bath containing the rings. The effects of nitric oxide inhibition with L-NAME, on the responses to artesunate were also assessed. Lastly the effects on the contractile responses of the rings to noradrenaline (NA) were determined before and after incubation in artesunate.

RESULTS

Cumulative addition of artesunate from 6 x 10(-4) to 6 x 10(-1) mg/ml resulted in relaxation of pre-contracted aortic rings. L-NAME significantly reduced the relaxation response to artesunate (P < 0.05). Vascular contraction response to NA was significantly reduced (P < 0.01) following the addition of artesunate.

CONCLUSION

Artesunate causes relaxation of precontracted rat aortic rings which is partly mediated by Nitric Oxide (EDRF). It also reduces the contractile responses of the rings to noradrenaline.

Antioxidant activities of methanolic extract of Sapium ellipticum

The stem bark extract of S. ellipticum (Hochst) Pax was investigated for its antioxidant properties in this study. The extract was evaluated for antioxidant activity in vitro in terms of its ability to inhibit lipid peroxidation and its free radical scavenging, reducing and metal chelation powers. The total amount of phenolic compounds in the extract was also determined in terms of gallic acid equivalent. The extract produced effective free radical scavenging and reducing activities in a dose dependent fashion. The extract exhibited noticeable inhibition of lipid peroxidation of linoleic acid emulsion. These activities were less than that of ascorbic acid and 2,6-Di-tert-butyl-4-methylphenol used as positive controls. The extract however demonstrated poor iron chelating ability compared to ethylene diamine tetraacetic acid. The total phenolic content of the extract was 50.61 +/- 0.08 mg g(-1) in terms of gallic acid. This study showed that the stem bark extract of S. ellipticum exhibits significant antioxidant activity and is a good source of natural antioxidants.

The physicochemical and antibacterial properties of ciprofloxacin-Mg2+ complex

PURPOSE

Co-administration of quinolone antibiotics with cation-containing medicaments such as, antacids has been reported to influence the overall bioavailability leading to subtherapeutic plasma concentrations of these antibiotics in humans.

OBJECTIVES OF THE STUDY

The present work was designed to evaluate the binding constant, binding molar ratio, influence of temperature on the binding constant of ciprofloxacin-Mg2+ and to determine the antimicrobial activity of ciprofloxacin and ciprofloxacin-Mg2+.

METHODS

Job's method of continuous variation and Bonesi-Hildebrand equation were adopted to determine the molar ratio and stability constant respectively. The antibacterial activity was determined by the Agar diffusion method.

RESULTS

A complexation molar ratio of 1:1 was obtained for ciprofloxacin-Mg2+ complex. The stability constants were 3.59 and 3.50 at 25 degrees C and 60 degrees C respectively. There was a significant difference between the zones of inhibition of ciprofloxacin-Mg2+ complex and that of ciprofloxacin alone against E. coli, P. aeruginosa, and S. aureus (p < 0.05). This difference showed that the complex formed was not as active as ciprofloxacin.

CONCLUSION

The present studies have shown that ciprofloxacin readily complex with Mg2+ and that the stability constant was temperature dependent. The antibacterial activity of ciprofloxacin was markedly reduced in the presence of Mg2+. Concomitant administration of ciprofloxacin with Mg2. containing medicaments should be avoided to prevent resistance.

Invitro evaluation of the neutralising capacity of twenty brands of antacids in Lagos, Nigeria

BACKGROUND

The use of substandard drugs is a great threat to the lives of people in the community. Identification of substandard drugs is important to exclude their use in clinical practice. These drugs may lead to reduced efficacy of pharmacotherapy. Antacid preparations are weakly basic and consist of metal salts, most commonly aluminium hydroxide or magnesium hydroxide. These salts dissociate to neutralise gastric acid and form neutral salts. The ultimate goal of antacid therapy is to reduce the concentration and the total load of acid in gastric juice with a pH of 1.3 to a pH between 3.5 and 5.0.

OBJECTIVE

The aim of this work is to carry out an in-vitro test on the acid neutralising capacity (ANC) of commonly available antacid brands in Lagos market.

METHOD

The British pharmacopoeia (BP) method of analysis of antacids was adopted. Twenty different brands of antacid suspensions and tablets were analysed.

RESULT

Brand SH suspension gave the highest neutralising capacity, 101.65 ml +/- 0.15, while brand SN gave the lowest, 99.75 ml +/- 0.75. All the fourteen antacid suspensions analysed complied with the official specification and therefore passed the analysis. Brand TB tablet gave the highest acid neutralising capacity (ANC), 54.10 ml +/- 0.2 while brand TD 49.50 ml +/- 0.1 gave the lowest. All the six antacid tablet brands analysed passed the assay. The ANC of an antacid is a parameter used to measure the effectiveness of an antacid in relieving ulcer pain.

CONCLUSION

The acid-neutralising capacity of the antacid brands analysed were within the BP specification. The acid neutralising capacity of antacids should be determined before administration.

Evaluation of Antioxidant Properties of Phaulopsis fascisepala C.B.Cl. (Acanthaceae)

The antioxidant activities of crude extract of Phaulopsis fascisepala leaf were evaluated and compared with alpha-tocopherol and BHT as synthetic antioxidants and ascorbic acid as natural-based antioxidant. In vitro, we studied its antioxidative activities, radical-scavenging effects, Fe(2+)-chelating ability and reducing power. The total phenolic content was determined and expressed in gallic acid equivalent. The extract showed variable activities in all of these in vitro tests. The antioxidant effect of P. fascisepala was strongly dose dependent, increased with increasing leaf extract dose and then leveled off with further increase in extract dose. Compared to other antioxidants used in the study, alpha-Tocopherol, ascorbic acid and BHT, P. fascisepala leaf extract showed less scavenging effect on alpha,alpha,-diphenyl-beta-picrylhydrazyl (DPPH) radical and less reducing power on Fe(3+)/ferricyanide complex but better Fe(2+)-chelating ability. These results revealed the in vitro antioxidant activity of P. fascisepala. Further investigations are necessary to verify these activities in vivo.

Effect of Five Alive fruit juice on the dissolution and absorption profiles of ciprofloxacin

OBJECTIVE

To determine the effect of interaction of five Alive fruit juice on the dissolution and absorption profiles of ciprofloxacin tablets using urinary excretion.

METHODS

In-vitro dissolution of ciprofloxacin 500 mg tablets was studied using US Pharmacopoeia dissolution apparatus II. This was conducted using 0.1N HCl and equal volumes of the fruit juice and 0.1N HCL. Samples were collected at predetermined time intervals for two hours. For the in-vivo study, eleven (5 males and 6 females) healthy volunteers participated in an open, single dose, cross-over randomized trial. After an overnight fasting, each volunteer either ingested a 500 mg ciprofloxacin tablet with 250 ml table water or with the fruit juice. Total urine voided was collected for 72 hrs after each dose of ciprofloxacin. Dissolution and urine samples were assayed using a controlled and validated UV spectrophotometric analysis.

RESULTS

A lag time of 5 minutes was observed in dissolution profile of ciprofloxacin in the juice. The percent dissolved of ciprofloxacin in 0.1NHCl and fruit juice were found to be dissimilar (f2 =18.2) using similarity factor. There was statistical difference between the K(el) (elimination constant), K(e) (excretion rate) and X(u) (cumulative amount excreted unchanged) of subjects on water (0.1759 +/- 0.0144; 12.81 +/- 1.36; 375.5 +/- 41.2) and that of fruit juice (0.1250 +/- 0.0161; 7.6 +/- 1.07; 241.6 +/- 34.0). However, there was no difference between the t(1/2) of the subjects (4.2 +/- 0.3; 5.5 +/- 0.8). There was a decrease in relative availability of the drug by 35.75%.

CONCLUSION

We conclude that the absorption of ciprofloxacin can be reduced by concomitant ingestion of the juice containing calcium carbonate and grape. Therefore to avoid drug therapeutic failures and subsequent bacterial resistance as a result of subtherapeutic level of the drug in the systemic circulation, ingestion of the juice with ciprofloxacin should be discouraged.