Phenotypic and Molecular Characterization of ß-Lactamases among Enterobacterial Uropathogens in Southeastern Nigeria.

Little is known about the molecular basis of antibiotic resistance among uropathogens in Southeast Nigeria. The aim of the study was to characterize enterobacterial uropathogens with respect to drug resistance. One hundred (100) enterobacterial uropathogens were studied. Their antibiotic susceptibility patterns were evaluated using disk diffusion, screened, and confirmed phenotypically for the presence of ß-lactamases: ESBL, AmpC, carbapenemase, and MBLs. Screen positives were further tested for various ß-lactamase genes by PCR. Our isolates showed variable resistance to most drugs tested. Out of the 58 ESBL screen positive E. coli, 35 were confirmed positive with PCR. The predominant ESBL gene was blaTEM while blaSPM was the most prevalent among MBL genes. Forty-six percentage of the screen positive Salmonella isolates coharbored blaTEM + SHV genes. Nine of the 10 ESBL screen positive K. pneumoniae were phenotypically and PCR positive. Three isolates of K. pneumoniae were positive for MBL genes. All the 10 C. freundii were positive for ESBL genes. The study showed high prevalence of drug-resistant genes among the enterobacterial uropathogens. Majority of the uropathogens harbored >1 antibiotic-resistant gene, and the most predominant gene was ESBL (blaTEM) followed by the MBL (SPM) gene.

In-vivo studies of targeted and localized cancer drug release from microporous poly-di-methyl-siloxane (PDMS) devices for the treatment of triple negative breast cancer.

Triple-negative breast cancer (TNBC) treatment is challenging and frequently characterized by an aggressive phenotype and low prognosis in comparison to other subtypes. This paper presents fabricated implantable drug-loaded microporous poly-di-methyl-siloxane (PDMS) devices for the delivery of targeted therapeutic agents [Luteinizing Hormone-Releasing Hormone conjugated paclitaxel (PTX-LHRH) and Luteinizing Hormone-Releasing Hormone conjugated prodigiosin (PG-LHRH)] for the treatment and possible prevention of triple-negative cancer recurrence. In vitro assessment using the Alamar blue assay demonstrated a significant reduction (p < 0.05) in percentage of cell growth in a time-dependent manner in the groups treated with PG, PG-LHRH, PTX, and PTX-LHRH. Subcutaneous triple-negative xenograft breast tumors were then induced in athymic female nude mice that were four weeks old. Two weeks later, the tumors were surgically but partially removed, and the device implanted. Mice were observed for tumor regrowth and organ toxicity. The animal study revealed that there was no tumor regrowth, six weeks post-treatment, when the LHRH targeted drugs (LHRH-PTX and LHRH-PGS) were used for the treatment. The possible cytotoxic effects of the released drugs on the liver, kidney, and lung are assessed using quantitative biochemical assay from blood samples of the treatment groups. Ex vivo histopathological results from organ tissues showed that the targeted cancer drugs released from the implantable drug-loaded device did not induce any adverse effect on the liver, kidneys, or lungs, based on the results of qualitative toxicity studies. The implications of the results are discussed for the targeted and localized treatment of triple negative breast cancer.

Preliminary evaluation of the immunoenhancement potential of Newcastle disease vaccine formulated as a cationic liposome.

This study evaluates the enhancement of immune response of birds to Newcastle disease (ND) vaccine encapsulated in 1,2-dioleoyl-3-trimethylammonium propane (DOTAP)-based liposomes. The vesicles of the liposomal ND vaccine were physically characterized for shape, particle size and zeta potential. The results of the analyses showed that vesicles of the liposomal ND vaccine were spherical and tightly packed. The mean size distribution was below 100 nm. The mean zeta potential was 24 mV. Sixty experimental birds were then divided into an unvaccinated group, a liposomal ND vaccine group and a live La Sota(®) vaccine group. Both the liposomal ND vaccine and live La Sota(®) vaccine groups were vaccinated orally at 3 and 6 weeks of age. The mean antibody titres, total and differential white blood cell count, and blood chemistry, respectively, were assessed. Ten birds from each group were challenged by oral administration of 0.2 ml virulent Herts 33 strain at 9 weeks of age. The log(2) mean antibody titre induced by the liposomal ND vaccine after secondary immunization of the birds was 9.60±0.95 while that of the live La Sota( (®) ) vaccine was 6.00±0.63. Nine of the 10 challenged birds in the unvaccinated group died while none died from the liposomal ND vaccine group or the live La Sota(®) vaccine group. After the boost vaccination, the chickens vaccinated with the liposomal ND vaccine had a higher mean antibody titre, indicating that encapsulating ND vaccine in DOTAP-based liposome induced significantly higher immunity than the live La Sota(®) vaccine.

Antagonistic antimalarial properties of pawpaw leaf aqueous extract in combination with artesunic acid in Plasmodium berghei-infected mice.

BACKGROUND & OBJECTIVES: Artemisinins, the main stay in the treatment of malaria are used in combinations with other antimalarials to forestall resistance, as artemisinin-combination therapies (ACTs). However, ACTs are expensive and some of the non-artemisinin components are not well-tolerated by patients. There are several folkloric and scientific proofs of the efficacy of herbal remedies for malaria. Mature leaves of Carica papaya is widely used to treat malaria in several African countries. An ACT involving a medicinal herb extract or its active constituent(s) will provide an indigenous alternative/herbal ACT. METHODS: Mature fresh leaves of Carica papaya were grounded and macerated in cold distilled water for 24 h and the extract (PCE) was stored in the refrigerator for seven days. Fresh extracts were made as needed. The antiplasmodial activity of PCE and/or artesunic acid were determined by using the Peter's 4-day suppressive test in Plasmodium berghei-infected mice. The ED50 and ED90 were calculated from the dose-response relationships. RESULTS: The combination of 50 mg/kg of PCE and 15 mg/kg of artesunic acid produced a significant reduction of parasitemia (81.25%), compared to 50 mg/kg PCE alone (37.7%). The mean survival time of the combinations of PCE and 15 mg/kg of artesunic acid, and PCE alone followed a dose-dependent manner. The ED50 of PCE showed that it has a very good activity. The isobolar equivalent (IE) calculated from the ED90 of PCE in combination with artesunic acid showed that the interaction was antagonistic. INTERPRETATION & CONCLUSION: Although pawpaw alone was found to have a very good activity, its combination with artesunic acid is antagonistic. Combinations of artemisinins and pawpaw show little promise for combination therapy development.

Adjuvant properties of AcF1, an immunostimulant fraction of Alchornea cordifolia extract.

As a result of strong experimental data supporting effectiveness and safety, herb-based immunomodulators are paving way as alternative sources of potent adjuvants for vaccines. In this study, the immunostimulatory and adjuvant properties of AcF1, a flavonoids-rich fraction of Alchornea cordifolia extract, was evaluated. In vitro, AcF1 was shown to activate total splenocytes, CD4+ T cells, and B cells, inducing remarkable increases in CD69 expression, profound proliferation, and increased IL-4 and IFN-gamma expression by the naïve splenic cells in a concentration-dependent manner. Lympho-activation and proliferation induced by AcF1 was partially inhibited by U0126, a selective mitogen activated protein kinase kinase (MKK) inhibitor. Additionally, AcF1 was shown to induce structural and functional maturation of bone marrow-derived dendritic cells (BM-DCs) and their specific-antigen presentation functions. Used as an adjuvant in a homologous prime-boost OVA immunisation in C57BL/6 mice, AcF1 significantly (P<0.05) increased the level of OVA-specific antibody titres in the sera of immunised mice, compared to the control group immunised with OVA alone. The results of this study show AcF1 as a potent immunostimulant and a potential adjuvant for further study in combination with other vaccine antigens.

The effects of Phyllanthus niruri aqueous extract on the activation of murine lymphocytes and bone marrow-derived macrophages.

Phyllanthus niruri L. (Euphorbiaceae) is acclaimed world-wide for its versatile ethnomedicinal uses. It features in recipes used by some herbalists to manage different diseases, including claims of efficacy against many life-threatening infections, such as HIV/AIDS and hepatitis. In order to understand the mechanisms and the involvement of the immune system in mediating these activities, the effects of the aqueous extract of P. niruri on the activation of murine lymphocytes and macrophages were investigated. The study showed that the extract of P. niruri is a potent murine lymphocytes mitogen, inducing significant (p < 0.01) increases in the expression of surface activation maker (CD69) and proliferation of B and T lymphocytes. The production of interferon-gamma (IFN- gamma) and interleukine-4 (IL-4) by P. niruri extract-stimulated naïve splenocytes cultures was also significantly (p < 0.05) increased in a concentration-dependent manner. Various indices of activation and functions murine bone marrow-derived macrophages were significantly (p < 0.05) enhanced by pre-treatment with the extract, including phagocytosis, lysosomal enzymes activity, and TNF-alpha release. Phyllanthus niruri extract was also shown to modulate nitric oxide release by macrophages. These activities suggest that stimulation of the immune system by the extracts of P. niruri could be partly responsible for the ethnomedicinal applications in the management of infectious diseases.

Broad spectrum antiviral fractions from the lichen Ramalina farinacea (L.) Ach.

BACKGROUND: An ethylacetate-soluble fraction (ET4) from the lichen Ramalina farinacea has previously been shown to inhibit the infectivity of lentiviral and adenoviral vectors, as well as wild-type HIV-1. We now determined the antiviral activity of ET4 against other wild-type viruses, including the herpes simplex virus type 1 (HSV-1) and the respiratory syncytial virus (RSV). METHODS: Wild-type HIV-1, HSV-1 or RSV were pre-incubated with various concentrations of ET4 for 30 min at 37 degrees C before adding to P4CCR5 indicator cell line (HIV-1), ELVIS TM indicator cell line (HSV-1) or HEp2 cell line (RSV) in 96-well microtitre plates. Controls contain virus alone without ET4. The anti-HIV and anti-HSV activities were quantified by estimating beta-galactosidase expression of the respective indicator cell lines while the anti-RSV activity was determined via an immunofluorescent technique, employing monoclonal mouse antibody against the P-protein of RSV. Toxicity of ET4 to cell lines was evaluated in parallel using either the BrdU incorporation method or the MTT method. The effect of ET4 on the enzymatic activity of HIV-1 reverse transcriptase was also evaluated using a chemiluminescent reverse transcriptase assay. Bioassay-guided fractionation of the whole methanol extract of R. farinacea involved sequential screening of HPLC fractions using a vector-based assay technique. RESULTS: ET4 inhibited HSV-1 and RSV potently (IC(50)=6.09 and 3.65 microg/ml, respectively). Time-of-addition studies suggest that both entry and post-entry steps of the HIV-1 replication cycle and the entry step of the RSV replication cycle are targeted. Furthermore, ET4 inhibited HIV-1 reverse transcriptase with an IC(50) of 0.022 microg/ml. Bioassay-guided fractionation of ET4 led to the identification sub-fraction rfO, with activity against lentiviral vector and HIV-1 (RNA viruses) but not against HSV-1 (DNA virus) and sub-fraction rfM, with activity against HSV-1 but not against the lentiviral vector. CONCLUSIONS: ET4 represents a novel fraction from the lichen R. farinacea with broad spectrum antiviral activity against DNA viruses (adenovirus and HSV-1) and RNA viruses (HIV-1 and RSV). The effect against DNA and RNA viruses is mediated by different sub-fractions within R. farinacea.

Immunomodulatory activities of kolaviron, a mixture of three related biflavonoids of Garcinia kola Heckel.

The immunomodulatory properties of kolaviron (KV), a mixture of three related biflavonoids of Garcinia kola Heckel (Clusiaceae), were investigated. The study was conducted using in vitro and in vivo immunocompetent and immunocompromised animal models. KV (250 and 500 mg/kg) produced a dose-dependent and significant (p < 0.05) inhibition of delayed-type hypersensitivity in rats and also caused a significant (p < 0.05) increase in the primary and secondary sheep erythrocytes-specific antibody titres in rats. In vitro, KV inhibited the classical complement system at concentrations greater than 100 microg/ml. The administration of KV ameliorated the cyclophosphamide-induced leukopenia and increased the proportion of lymphocytes count in rats after 14 days of treatment. Administration of KV on alternate days after immunosuppression with cyclophospamide increased the rate of excision wound closure and reduced epithelialization period from 21.75 to 15.5 days. This study established the immunomodulatory and immunorestorative properties of KV, which could be harnessed for possible clinical benefits to immunodeficient patients.

In vitro bioequivalence study of nine brands of artesunate tablets marketed in Nigeria.

BACKGROUND & OBJECTIVES: The availability of numerous brands of artesunate in our drug market today places clinicians and pharmacists in a difficult situation of choice of a suitable brand or the possibility of alternative use. The aim of the present study was to predict the bioequivalence of nine brands of artesunate tablets marketed in Nigeria using in vitro tests. METHODS: The in vitro dissolution study was carried out on the nine brands of artesunate tablets using the basket method according to US Pharmacopoeia (USP) guidelines. Other general quality assessment tests like hardness and disintegration time were also determined. RESULTS: All the brands tested passed the British Pharmacopoeia (BP) standard for disintegration time. Only AT2, AT4, AT6 and AT9 passed the standard for hardness. There were significant differences in the dissolution profiles of the nine brands. All the brands except AT1, however, released >70% of artesunate within 30 min. Four of the brands AT5, AT6, AT7 and AT8 exhibited >90% dissolution in <10 min. The other brands AT1, AT2, AT3, AT4 and AT9 (innovator brand) have calculated similarity factors of 23.8, 59.8, 50, 54.8 and 100. INTERPRETATION & CONCLUSION: Based on the in vitro tests, AT5, AT6, AT7 and AT8 are considered bioequivalent and interchangeable, while AT2, AT3 and AT4 are considered bioequivalent and interchangeable with the innovator brand (AT9). AT1 has very low dissolution rate, which will likely result in poor bioavailability. The results show the need for constant monitoring of new brands of artesunate introduced into the drug market to ascertain bioequivalence and conformity with pharmacopoeia standards.

Evidence for the spectroscopic determination of artesunate in dosage form.

BACKGROUND & OBJECTIVES: Resistance to conventional antimalarials triggered off new policies to circumvent the devastating consequences of malaria especially in the trans-Saharan Africa. The use of artemisinin-based combinations as first line drug in treatment of uncomplicated malaria was then advocated and adopted by the World Health Organization (WHO). In Nigeria, this new policy has witnessed a surge in the number of circulating brands of such combinations. Unfortunately, at present, there are no "on-the-spot" cheap and reliable assay procedures for artesunate-based combinations. This is what the present research aims to achieve. METHODS: Ultraviolet absorption spectroscopy was used to establish the wavelength of maximum absorbance for pure powder of artesunate and then the Beer's plot generated. This was validated and used to assay nine brands (X1-X9) of artesunate in Nigerian drug market. RESULTS: Distinctive ultraviolet absorption at 287 nm of pure sample of Artesunate in simulated intestinal fluid (SIF) afforded a simple, precise and the most reliable method for the analysis of nine different brands of Artesunate marketed in Nigeria. SIF does not have any appreciable absorption in the ultraviolet region. This simple method yielded a Beer's plot for Artesunate with high correlation (R2) of 0.9972 +/- 0.00016 and was reproducible. The Beer's plot was obeyed in concentration range of 10-200 mg%. The limits of detection (sensitivity) and quantitation were found to be 0.471 mg/ml and 1.27 mg/ml respectively. The results showed that only four out of the nine brands assayed had deviations from label claims that were within acceptable limits. INTERPRETATION & CONCLUSION: Based on these convincing data, simple ultraviolet spectroscopy at 287 nm could be used to assay artesunate in formulations.

Potential anti-respiratory syncytial virus lead compounds from Aglaia species.

Although the global prevalence of respiratory syncytial virus (RSV) infection, especially among infants and young children is on the increase, there are only limited therapeutic options for treatment of this disease. Therefore, the search for novel antiviral inhibitors of RSV has become more intensive. In a pilot screening of eighteen compounds from various Aglaia species for anti-RSV activity, we identified dammarenolic acid (ignT1), aglaiol (dupT1) and niloticin (cucT1) as potential anti-RSV compounds, with ignT1 being the most potent. Methylation of ignT1 results in a complete loss of anti-RSV activity. Time of addition studies reveal that both ignT1 and dupT1 target the RSV replication at a post-entry stage, although ignT1 was more potent. Dammarenolic acid (ignT1) was also more cytotoxic than aglaiol (dupT1). By carrying out parallel anti-RSV screening with aphidicolin (a highly cytotoxic diterpenoid) and ignT1, we showed that although aphidicolin was more cytotoxic than ignT1, it had virtually no anti-RSV activity. Therefore, dammarenolic acid, aglaiol and niloticin demonstrate potent anti-RSV activity that shouldbe explored further in the current search for anti-RSV therapeutic agents.

Antibacterial and wound healing properties of methanolic extracts of some Nigerian medicinal plants.

This study was conducted to evaluate methanolic extracts of Ageratum conyzoides, Anthocleista djalonensis, Napoleona imperialis, Ocimum gratissimum, and Psidium guajava for antibacterial and wound healing properties. Antibacterial properties of the extracts were studied against eleven wound isolates (Staphylococcus aureus (four strains), E. coli (two strains), Pseudomonas aeruginosa (one strain), Proteus spp. (three strains), and Shigella spp. (one strain)) using the well diffusion method. Wound healing properties of Ageratum conyzoides, Anthocleista djalonensis, Napoleonaea imperialis, and Ocimum gratissimum were determined using the excision wound model. Extract of Napoleona imperialis inhibited growth of all the test bacterial strains while Psidium guajava and Anthocleista djalonensis extracts prevented growth of 81.8 and 72.7% of the test organisms, respectively. Ageratum conyzoides and Ocimum gratissimum extracts did not inhibit growth of any of the test organisms. More than 90% wound healing was recorded in the extract and cicatrin powder treated groups by 14 days post surgery, where as 72% healing was observed in the distilled water-treated group. The percentage healing in the distilled water-treated group was significantly different (P<0.001) from those of extract and antibiotic-treated groups.

Evaluation of extracts of the root of Landolphia owerrience for antibacterial activity.

Ethanolic and aqueous (cold and hot) extracts of Landolphia owerrience root parts (whole-root, root-bark and root-wood) were tested for activity against ten bacterial strains using agar-well diffusion and macro-broth dilution methods, respectively. The ethanolic extracts of the whole-root and root-wood were active against 100 and 80% of the test organisms, respectively. Ethanolic and aqueous extracts of the root-bark were moderately active while the aqueous (cold and hot) extracts of the root-wood exhibited little or no activity. Out of the nine extracts prepared, 66.7% were active against Staphylococcus aureus ATCC 12600, 55.6% variously against each of Pseudomonas aeruginosa ATCC 10145 and local clinical isolates of P. aeruginosa, S. aureus, Escherichia coli and Salmonella typhi, 44.4% against Proteus sp., 33.3% against Bacillus subtilis ATCC 6051 and 22.2% against E. coli ATCC 11775. The agar-well-determined MIC values for the ethanolic whole-root extract (0.78-50 mg/ml) were higher (indicating lower activity) than the corresponding macro-broth-determined values (0.39-50 mg/ml) probably because of slow diffusion rates of the active constituents of the extract in agar. On the other hand, the differences could be due to the effects of DMSO used to dissolve the ethanolic extracts in the agar-well diffusion tests. Similar discrepancies in the MIC values detectable with the two test methods were apparent in the root-wood extract and the control drug, Gentamycin, except that in the latter the agar-well-determined MIC values (0.125-8.0 microg/ml) were lower than the macro-broth-determined values (0.125-64 microg/ml). The strong activity of the ethanolic extracts against known etiologic agents of diseases traditionally treated with L. owerrience root of similar preparations provides scientific justification for the use of the herb in ethnomedical practice in Nigeria.

Potential use of tea extract as a complementary mouthwash: comparative evaluation of two commercial samples.

OBJECTIVE: To evaluate the potential of using tea extracts as complementary mouthwash and to test the comparative efficacy of two commercial samples. DESIGN: A randomized controlled trial with 30 healthy human volunteers was carried out. The subjects were randomly assigned to 5 groups of 6 subjects per group. The ability of Ndu tea (from Cameroon) and Lipton tea (from Nigeria) to reduce colony forming units (CFU) in the liquid expectorated after 60 seconds of gargling from the mouth of the volunteers at 5 and 60 minutes were evaluated. These were compared to the values obtained from bank water and Minty Brett (thymol 0.047%), a standard antiseptic. SETTING: University of Nigeria, Nsukka, Enugu State, Nigeria. SUBJECTS: Thirty healthy human volunteers (18 males and 12 females, between 22-30 years of age) who met the eligibility requirement of being nonsmokers and not taking any other antimicrobial agent were selected for the study. RESULT: Relative to the bank water, the results indicated that the hot water extract of both teas significantly (p < 0.05) reduced CFU per milliliter in the liquid expectorated after gargling at both 5 and 60 minutes. Minty Brett showed higher activity than both tea extracts; however, unlike Minty Brett both extracts still reduced the CFU per milliliter at time 60 minutes (an indication of longer duration of activity). The combination of the tea extracts with sodium lauryl sulfate (1.2% w/v), a surfactant and emulsifier, significantly increased the antimicrobial activity relative to each tea alone. Comparatively, the activity of Ndu tea was found to be slightly higher than that of Lipton tea but this was not significant (p < 0.05). CONCLUSION: Lipton and Ndu tea extracts potently reduced the CFU per milliliter. This activity was potentiated by sodium lauryl sulfate. Although Minty Brett had more potent antimicrobial activity, both tea extracts have longer duration of activity. The results indicate the potential usefulness of tea extracts as a complementary mouthwash.

Antimicrobial activities of some amino derivatives of 5, 7-dibromo-2-methyl-8-benzoyloxyquinoline.

In an attempt to design and synthesize more potent quinoline-based chemotherapeutic agents structural modifications of 5, 7-Dibromo-2-methyl-8-benzoyloxyqinoline was carried out. The replacement of the bromine atoms with the requisite alkylamino compound gave four amino-derivatives viz: bis(dipropylamino)-dipyrrolidino-, dipiperidino- and dipiperazino derivatives. The antimicrobial activities of these compounds were investigated against selected Gram-positive bacteria (Staphylococcus aureus and Bacillus subtilis), Gram-negative bacteria (Escherichin coli, Pseudomonas aeruginosa and Klebsiella spp) and yeast (Candida albicans). All the compounds showed broad or significant antimicrobial activity, which varied from two to ninety times that of the parent compound. The dipyrrolidino derivative was the most effective against Gram-positive bacteria and yeast while the dipiperidino derivative was the most effective against Gram-negative bacteria. No correlation has been established between the minimum inhibitory, (MIC) concentrations of the derivatives and the structural modifications.

Evaluation of the physico-chemical properties of a new polysaccharide gum from Prosopis africana.

The gum obtained from the ripe seeds of Prosopis africana was processed to compendial standard for plant gums and characterised. Toxicological studies of the polysaccharide on mice showed the material to be safe. The material hydrates slowly in aqueous media to form a colloidal dispersion. Swelling studies on the gum shows that the gum has a higher swelling capacity than methylcellulose. Rheological studies showed that the material is more viscous than tragacanth gum at equivalent concentrations. Acid hydrolysis and thin layer chromatography of the resulting hydrolysates showed that the gum contains glucose, fructose, galactose and xylose as the monosaccharide components. Microbial tests showed the gum to contain 8.26 x 10(4) viable cells per gram when freshly prepared. Other properties of the gum evaluated includes; melting or charring temperature, optical properties, true density, ash values, element content as well as its reactions with lead subacetate solution and 0.02 M iodine.

Detection of halofantrine, mefloquine and proguanil by charge--transfer complexation on thin layer plates.

A complexation phenomenon between certain antimalarials (as donors) and chloranilic acid (as an acceptor) has been studied using thin-layer-chromatography (TLC). The antimalarials were subjected to charge--transfer complexation using chloranilic acid as the pi-acceptor. This technique was used for the qualitative detection of the drugs. Drug-spotted TLC plates, when developed in suitable solvent systems and sprayed with the pi-acceptor gave a spontaneous purple colour. The Rr values of the three drugs were found to be constant and specific for each drug sample in a particular solvent system.

Drug adsorption studies on pregelatinized gladiolus starch.

A comparative evaluation of the adsorption properties of pregelatinized gladiolus starch and activated charcoal on such drugs as chloroquine phosphate, aspirin, ampicillin and caffeine has been made. Results indicate that the adsorption capacity increases with increase in concentration of adsorbent used. Pregelatinized gladiolus starch exhibited a higher complexation affinity for chloroquine phosphate than activated charcoal, while the reverse was observed in the case of aspirin. The adsorption of caffeine and ampicillin was insignificant with the adsorbents. The desorption profile was slower for the pregelatinized gladiolus starch than for activated charcoal. This slow release property might be exploited in formulations where sustained-release is the desired goal.

Preliminary physicochemical evaluations and bioactive properties of column fractions from the lichen.

The chloroform-soluble portion of an ethanolic extract of the lichen Ramalina farinacea was separated by column chromatography using n-hexane: ethylacetate (4:1) as the mobile phase and silica gel S as the stationary phase. Four column fractions (B, C, H and I) and the n-hexane-soluble portion of the ethanolic extract (N) were screened for possible biological activity by the Brine Shrimp Lethality Bioassay Technique. Some physicochemical evaluations of the column fractions such as pH determinations, ultraviolet (UV) absorption spectra, solubility profile and some chemical tests were also carried out. Phytochemical and elemental analysis of the crude lichen material was equally carried out. Results showed that all the fractions and the n-hexane extract were biologically active with the bioactivity of N > B > C > I > H. Fractions B and C were both acidic and evaluation of their solubility profile, UV spectra and some chemical reactions suggest that the fractions are possibly depsides and depsidones respectively.