Phytochemical and antimicrobial studies on Detarium microcarpum Guill and Sperr (Caesalpinioceae) seeds coat

Ninety percent aqueous methanol extract of the seeds coat (32.324%, w/w) of Detarium microcarpum was screened against clinical isolates of Staphylococcus aureus, Bacillus subtilis, Escherichia coli, Pseudomona aeruginosa, Klebsiella pneumonia, Salmonella paratyphi and Candida albicans. A broad spectrum antimicrobial activity at the test concentration of 10 mg/ml comparable with the control drugs chloramphenicol and penicillin G for bacteria and nystatin for the mould C. albicans was observed. On bio-guided fractionation, the ethyl acetate soluble fraction (ES) retains the observed spectrum of antimicrobial activity. Preparative thin layer  chromatographic separation of the active ESF on silica gel 60G using butan-2-one : chloroform : acetic acid : water (40:40:2:1 v/v/v/v) gave eight constituent bands: B1 (Rf = 0.000), B2 (Rf = 0.079), B3 (Rf =  0.250), B4 (Rf = 0.286), B5 (Rf = 0.500), B6 (Rf = 0.686), B7(Rf = 0.814), and B8 (Rf = 1.000). B1 retained the observed antimicrobial activity spectrum, B2 and B3 showed residual inhibition against B. subtilis and B4 - B8 were inactive. Phytochemical screening indicated the presence steroidal saponins and flavonoids in B1, and flavonoids in B2 and B3. The UV visiblespectrum of B2 and B3 revealed the characteristic benzopyrone maxima (236 – 300 nm). Against the selected bacteria, MIC range of B1 of 1.0488 -2.8887 mg/ml was observed comparable to those of standard control (1.2357 - 3.3420 mg/ml) and chloramphenicol (2.0840 -3.9630 mg/ml) which is suggestive of resistant strains. This study revealed the antimicrobial principles in the seed coat of D. microcarpum to be steroidal saponins and flavonoids with the possibility of synergistic action.Key words: Detarium microcarpum, seed coat, antimicrobial activity, benzopyrone, flavonoids, steroidal saponins, phytoalexins

A Simple UV Spectrophotometric Method for the Determination of Levofloxacin in Dosage Formulations

Purpose: The present study was undertaken to develop a validated, rapid, simple and low-cost ultraviolet (UV) spectrophotometric method for estimating levofloxacin (LFX) in dosage preparations. Method: UV spectrophotometric analysis was performed spectrophotometrically at a pre-determined max of 290 nm with 0.1M HCl as diluent/blank. The method was validated for linearity, accuracy, precision, reproducibility, and specificity as per International Conference on Harmonization (ICH)guidelines. The method was also used in the determination of the content of levofloxacin in two commercial brands of levofloxacin in the Nigerian market. Results: The regression data for the calibration plots exhibited good linear relationship (r = 0.999) over a concentration range of 0.25 – 12.0 ìg/ml and the linear regression equation was y = 0.075x + 0.018.Mean recovery accuracy was 98.7 %, which was not significantly different from the expected value (p = 0.05), while coefficient of variation (CV) for both intra-day and inter-day was < 7 %. The method was specific for levofloxacin in the presence of common excipients, and when it was applied to two marketed brands, levofloxacin content was 99.69 ± 2.38 and 102.65 ± 3.64 %, respectively, of labeled claim. Conclusion: The proposed method gave good validation results and the statistical analysis performed proved that the method is precise, accurate and reproducible, and hence can be employed for routine analysis of LFX in bulk and commercial formulations

Gas chromatography-mass spectroscopic (GC-MS) analysis of n-Hexane extract of Lentinus tuber-regium (Fr) Fr (Polyporaceae) syn Pleurotus tuber regium Fr sclerotia

Purpose: To identify the chemical constituents of the n-hexane extract of the sclerotia of Lentinus tuber-regium (synonym Pleurotus tuber regium) using gas chromatography-mass spectroscopic (GCMS) techniques.Methods: The n-hexane extract of the sclerotia of Lentinus tuber regium was obtained by exhaustive Soxhlet extraction and analysed using gas chromatography-mass spectroscopic (MS) techniques. The structures of the identified constituents were confirmed on the basis of their fragmentation pattern in comparison with that obtained from the National Institute of Standards and Technology (NIST) reference library.Results: Seven fatty acids derivatives: heptadecenal, n-hexadecanoic acid, 1-eicosene, linoleic acid, oleic acid, linoleic acid ethyl ester, and octadecanoic acid, and five steroidal triterpenoids: cholesterol, α- ergostenol, anthraergostatetraenol, stigmasterol, and alpha-ergosta-4,6,8(14),22-tetraen-3-one. The major constituents characterised are α-ergosta-4,6,8(14), 22-tetraen-3-one (8.56 %) &gt; Anthraergostatetra-enol (7.19 %), &gt; n-hexadecanoic acid (6.29 %) &gt; linoleic acid (3.69  ).Conclusion: This study shows that L. tuber-regium is a veritable source of mono- and poly-unsaturated fatty acids, and ergosterol/provitamin D derivatives which may explain, in part, some of its reported nutraceutical benefits.Keywords: Lentinus tuber-regium, Fatty acids, Steroids, Gas chromatography, Mass spectroscop

A Spectrophotometric Method for the Determination of Ramipril in Solid Dosage Forms

Purpose: To develop a simple and cost effective spectrophotometer method for the determination of ACE inhibitor ramipril in dosage forms. Methods: UV spectrophotometry was used to develop and validate a simple method for the assay of ramipril in solid dosage form at λmax of 210 nm, as per International Conference on Harmonization (ICH) guidelines. Aqueous methanol (5 %) was used as the blank solvent. The method was validated for linearity, recovery, accuracy, precision, specificity in the presence of excipients, and also for inter-day stability under laboratory conditions. Results: Validation results showed linearity in the range 1 – 38 µg/ml; recovery accuracy 101.55%; regression equation Y = 0.0256X + 0.0697, R2 of 0.9942; precision RSD <2.00 %; and negligible interference from common excipients and colorants. The method was accurate (95 % confidence limit) compared to standard liquid chromatography (LC) method, with comparable reproducibility when used to assay a commercial product (Ramitace®, 2 and 5 mg tablets). Conclusion: The validated data were within allowable limits and therefore, the proposed method is recommended for routine quality control (QC) analysi