Anti-Respiratory Syncytial Virus Compounds from Two Endophytic Fungi Isolated from Nigerian Medicinal Plants.

Background: Respiratory syncytial virus (RSV) is known to cause severe respiratory infections particularly in infants younger than 2 years of age. The only approved drug, ribavirin, is expensive and is not likely to improve therapeutic outcome, thereby necessitating the search for safer and more potent alternatives from natural sources such as endophytic fungi. The present study aimed to investigate the anti-RSV activity of compounds from endophytic fungi. Methods: Two endophytic fungi Colletotrichum gloeosporioides and Pestalotiopsis thea were isolated from the fresh leaves of the host Nigerian plants Anthocleista djalonensis and Fagara zanthoxyloides, respectively. After fermentation in solid rice media, C. gloeosporioides afforded 4 known compounds 4-hydroxybenzoic acid (1), vanillic acid (2), ferulic acid (3) and Nb-acetyltryptamine (4) while P. thea afforded 3 known compounds chloroisosulochrin (5), ficipyrone A (6) and pestheic acid (7). The compounds were investigated for their anti-RSV activity using the HEP-2 cell lines and ribavirin as the standard drug. Results: Compound 5 was found to show the strongest inhibition of the RSV with IC50 of 4.22±1.03 µM (ribavirin 4.91±1.85 µM). Other compounds showed moderate inhibition of the virus (IC50 ranging from 45.00±0.98 to 259.23±2.36 µM). Conclusion: The results of the present study have shown that chloroisosulochrin (5), isolated from an endophytic fungus P. thea, possesses strong activity against RSV.

Topical anti-inflammatory constituents of lipophilic leaf fractions of Alchornea floribunda and Alchornea cordifolia.

The leaves of Alchornea floribunda and Alchornea cordifolia are used traditionally as topical anti-inflammatory agents. In this study, two highly lipophilic fractions AFLF and ACLF isolated from A. floribunda and A. cordifolia leaves respectively were investigated for topical anti-inflammatory effects using xylene-induced mice ear oedema as a model of inflammation. AFLF and ACLF at 5 mg per ear showed significant (p < 0.01) topical anti-inflammatory effect with oedema inhibitions of 64.0% and 79.0% at 2 h, respectively. When compared to indomethacin (5 mg per ear), these fractions showed significantly (p < 0.05) higher topical anti-inflammatory effect. Gas chromatography-mass spectrometry analysis revealed that AFLF is composed mainly of long chain saturated and unsaturated hydrocarbons (18.78%) and their oxygenated derivatives (1.89%); while ACLF is rich in volatile oils eugenol (21.26%) and cadinol (4.76%), and other constituents like, nanocosaine (36.86%) and steroid derivatives, ethyl iso-allocholate (4.59%) and 3-acetoxy-7,8-epoxylanostan-1-ol (15.86%). Analysis of the volatile oil (ACV) extracted from the fresh leaves of A. cordifolia revealed the presence of high concentrations of eugenol (41.7%), cadinol (2.46%), Caryophylene (1.04%), Linalool (30.59%) and (E)-α-bergamotene (4.54%). These compounds could be contributing to the topical anti-inflammatory effects of A. floribunda and A. cordifolia leaf extracts.

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.

A new anti-inflammatory flavonol glycoside from Alchornea floribunda leaves.

Alchornea floribunda leaves are widely used in African ethnomedicine for the management of acute and chronic inflammatory disorders. In the present study, bioactivity-guided fractionation of the ethyl acetate fraction of the methanol leaf extract of the plant material led to the isolation of a new flavonol glycoside (AFF1). The anti-inflammatory activity of this novel compound was evaluated using egg albumen-induced rat paw oedema as a model of inflammation. AFF1 showed significant inhibition of the rat paw oedema in a dose-dependent manner. The activity of AFF1 (50 mg kg(-1)) was higher than that of the standard anti-inflammatory drug, aspirin (100 mg kg(-1)). The compound also significantly (p < 0.001) inhibited heat-induced haemolysis of human erythrocytes in vitro. The structure of AFF1 was elucidated as 3,5,7,3'-tetrahydroxyflavone-3-O-alpha-L-rhamnoside, using a combination of UV, IR, 1D and 2D (COSY) 1H-NMR spectroscopy. This compound, in part, accounts for the anti-inflammatory effect of A. floribunda leaves.

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.

In vitro interaction between caffeine and some penicillin antibiotics against Staphylococcus aureus

Purpose: The aim of this study is to evaluate the in vitro interaction of some penicillins (amoxicillin; ampicillin and benzylpenicillin) and caffeine against Staphylococcus aureus. Method: The interaction between the penicillins and caffeine was studied using the Overlay Inoculum Susceptibility Disc (OLISD) method. Minimum inhibitory concentrations (MIC) of the drugs were determined separately and in combination with caffeine (5 and 10 mg/ml). Result: At 5 and 10 mg/ml; caffeine decreased the MIC of amoxicillin by 22 and 25 times respectively; while that of ampicillin was decreased by 6 and 8 times. The MIC of benzylpenicillin against Staphylococcus aureus was; however; increased by 59 and 40 times at caffeine concentrations of 5 and 10 mg/ml respectively. The inhibition zone diameter increment above 19(index of synergism in OLISD method) was recorded only for amoxicillin at amoxicillin concentrations of 7.81; 15.3; 31.25 and 62.5 mg/ml. Conclusion: The results of this study revealed that the concomitant use of caffeine and the studied antibiotics may potentiate the antibacterial effect of amoxicillin against Staphylococcus aureus; decrease that of benzylpenicillin and has virtually no effect on that of ampicillin. This implies that the intake of caffeine in form of analgesic combination or as tea; coffee; beverages or from other food sources may affect the effectiveness of a co-administered amoxicillin and bezylpenicillin

Anti-inflammatory effects of crude methanolic extract and fractions of Alchornea cordifolia leaves.

The leaves of Alchornea cordifolia were collected, identified, dried, and reduced to coarse powder and extracted with aqueous methanol. Using various solvent treatments, the powdered dried leaf was fractionated into five fractions, A1, A2, B, C, D and E. The fractions were subjected to phytochemical analysis to identify the biologically active constituents. The anti-inflammatory effects of crude methanolic extract (ME) of Alchornea cordifolia leaves and the five fractions were evaluated using egg-albumen-induced rat hind paw oedema as a model of inflammation. The crude extract was also subjected to acute toxicity test. Fraction A2, which exhibited the most promising anti-inflammatory effect, was also subjected to analgesic and ulcerogenic tests. Phytochemical analysis of the extracts showed the presence of terpenes, sterols, flavonoids, tannins, carbohydrates, glycosides, saponins and traces of alkaloids. The LD(50) of the aqueous ME was found to be 1131.4 mg/kg. The crude ME (50 mg/kg) gave anti-inflammatory activity which was significant (P<0.05) at all the observation times (1-3h). The different solvent fractions exhibited varying degrees of anti-inflammatory activities, with terpenoid fraction (A2) and the tannin-containing multi-component fraction (D) showing very high and significant (P<0.01) activity at 100mg/kg, with percentage inhibition of oedema value of 87.69 each. In conclusion, the aqueous ME of Alchornea cordifolia leaves could be beneficial in the management of different inflammatory disease states. Its anti-inflammatory activity may not be attributed only to the terpenoid content.