International Journal of Pharmacy and Pharmacology

International Journal of Pharmacy and Pharmacology ISSN: 2326-7267 Vol. 3 (10), pp. 001-008, October, 2012. © International Scholars Journals

Full Length Research Paper

In vitro inhibitory effects of Hypoxis obtusa and Dicoma anomala on cyp450 enzymes and p-glycoprotein

¹L.  Gwaza¹, A. R. Wolfe³, L. Z. Benet³, B. J. Guglielmo⁴, T. E. Chagwedera¹, C. C. Maponga¹ and C. M. Masimirembwa^2,5 *

¹School of Pharmacy, University of Zimbabwe, Harare, Zimbabwe.

²African Institute of Biomedical Science and Technology, Harare, Zimbabwe.

³Department of Biopharmaceutical Sciences, School of Pharmacy, University of California San Francisco, San Francisco, California, United States.

⁴Department of Clinical Pharmacy, School of Pharmacy, University of California San Francisco, San Francisco, California, United States.

⁵African Institute of Biomedical Science and Technology, 1st floor LAPF Center, Corner. J. Moyo / Chinhoyi Street, Harare, Zimbabwe.

Accepted 21 July, 2012

Abstract

Herbal medicines have been shown to cause clinically significant interactions with conventional medicines. Herbal medicines can alter the activity of drug- metabolizing enzymes and transporters, potentially resulting in herb -drug interactions. However, such information is generally not yet available for herbal medicines used only in developing nations. The inhibitory effects of crude extracts of Hypoxis obtusa and Dicoma anomala on cytochrome P450 (CYP) isoforms 1A2, 2C9, 2C19, 2D6 and 3A4 were evaluated in vitro using human liver microsomes. Herbal extracts at concentrations of 50 and 250 g/ml were tested for inhibition of P-glycoprotein (Pgp) transport across Caco-2 cell monolayers using 4.3 nM [3H]-digoxin as the substrate. Extracts of Hypoxis inhibited CYPs strongly, while extracts of Dicoma were moderate CYP inhibitors. The IC50 values for methanol and water extracts on CYP3A4 were 0.20 and 1.0 mg/ml for Hypoxis and 1.2 and 2.4 mg/ml for Dicoma. In the Pgp inhibition experiments, the (basolateral to apical) / (apical to basolateral) digoxin efflux ratios did not change significantly in the presence of the herbal extracts. Whilst, the extrapolation of the data to in vivo is rather speculative, there is need for assessment of the clinical significance of Hypoxis - drug interactions.

Key words: Herb-drug interactions, cytochrome P450, P-glycoprotein, Hypoxis obtusa, Dicoma anomala.

International Journal of Pharmacy and Pharmacology ISSN: 2326-7267 Vol. 3 (9), pp. 001-006, September, 2012. © International Scholars Journals

Full Length Research Paper

Influence of etherel and gibberellic acid on carbon metabolism, growth, and alkaloids accumulation in Catharanthus roseus L.

A. Misra, N. K. Srivastava, A. K. Srivastava and A. Khan

Central Institute of Medicinal and Aromatic Plants, P. O. CIMAP, Lucknow -226015, India.

Accepted 12 May, 2012

Abstract

Changes in growth parameters, 14C0₂ and [U-14C] -sucrose incorporation into the primary metabolic pools and essential oil were investigated in leaves and stems of Catharanthus roseus L. treated with etherel and gibberellic acid (GA). Compared to the control, GA and etherel treatments induced significant phenotypic changes and a decrease in chlorophyll content, carbon assimilation rate, and stomatal conductance. Treatment with etherel led to increased total incorporation of CO₂ into the leaves where as total incorporation from 14C sucrose was decreased. When 14CO ₂ was fed, the incorporation into the ethanol soluble fraction, sugars, organic acids, and essential oil was significantly higher in etherel treated leaves than in the control. However, [U-14C] -sucrose feeding led to decreased label incorporation in the ethanol-soluble fraction, sugars, organic acids, and essential oils compared to the control. When 14C0₂ was fed to GA treated leaves, label incorporation in ethanol-insoluble fraction, sugars, and oils was significantly higher than in the control. In contrast, when [U-14C]-sucrose was fed the incorporation in the ethanol soluble fraction, sugars, organic acids, and oil was significantly lower than in the control. Hence the hormone treatment induces a differential utilization of precursors for oil biosynthesis and accumulation and differences in partitioning of label between leaf and stem. Etherel and GA influence the partitioning of primary photosynthetic metabolites and thus modify plant growth and alkaloid accumulation.

Key words: Amino acids, chlorophyll, CO₂ and C-sucrose incorporation, organic acids, primary photosynthetic metabolites, stem, stomatal conductance, sugars, transpiration rate.

International Journal of Pharmacy and Pharmacology ISSN: 2326-7267 Vol. 3 (9), pp. 001-005, September, 2012. © International Scholars Journals

Full Length Research Paper

Informant consensus selection method: A reliability assessment on medicinal plants used in north western Nigeria for the treatment of diabetes mellitus

E. U. Etuk* and B. J. Mohammed

Department of Pharmacology, College of Health Sciences, Usmanu Danfodiyo University, Sokoto, Nigeria.

Accepted 24 April, 2012

Abstract

In this study, the reliability of informant consensus as a method of selecting medicinal plants for pharmacological screening was tested. Ten plants were selected based on the method and screened for antidiabetic properties using animal experimental model of the disease. The plants were selected from a list of medicinal plants obtained from a botanical survey of the region. A correlation between the two sets of data (Informant vs Experimental ranking orders) was examined. The results show that all the extracts of the selected plants (200 mg/kg) exhibited various degrees of blood glucose lowering activity. Vernonia amygdalina (67%), Calotropis procera (59%), Cassia gorotensis (53%) and Magnifera indica (35%) extracts produced a significant (P < 0.0.5%) reduction in blood glucose levels in diabetic rats while Angeissus leiocarpus (30%), Cassia arereh (19%), Gossypium hirsutum (17%), Khaya senegalensis (4%), Senna occidentalis (4%) and Moringa oleifera (4%) produced a non significant (P < 0.05%) effect. V. amygdalina was ranked highest both by the informant consensus and biological evaluation. There was a significant correlation (Rs = 0.8897) between the two sets of data. The study concluded that, informant consensus is a reliable method of selecting medicinal plant for pharmacological evaluation.

Key words: Informant consensus, diabetes mellitus, medicinal plants, screening.

International Journal of Pharmacy and Pharmacology ISSN: 2326-7267 Vol. 3 (8), pp. 001-005, August, 2012. © International Scholars Journals

Full Length Research Paper

In-vitro evaluation of the pharmaceutical quality of some ibuprofen tablets dispensed in Nigeria

Florence E. Eichie*, Ikhuoria M. Arhewoh and Oliver C. Ezeobi

Department of Pharmaceutics and Pharmaceutical Technology, Faculty of Pharmacy, University of Benin, Benin City 300001, Nigeria.

Accepted 13 May, 2012

Abstract

The purpose of this study was to determine the pharmaceutical quality of some Ibuprofen tablets dispensed in Nigerian. 19 different brands of Ibuprofen tablets were purchased from pharmacies and open markets in 3 states in Nigeria. The organoleptic and physicochemical properties of these Ibuprofen tablets were assessed according to British Pharmacopoeia (BP), and unofficial standards as recommended by the manufacturers. Of the 19 brands of tablets assessed, 12 brands passed the uniformity of content test while 15 brands passed the disintegration test and only four brands passed the dissolution test. Ibuprofen tablets dispensed in Nigeria varied considerably in their pharmaceutical quality. A strict check of the quality of brands of Ibuprofen by regulatory agencies and distributors before they are dispensed to the public is therefore recommended.

Key words: Ibuprofen tablets, pharmaceutical quality, dissolution, disintegration, dispensed.

International Journal of Pharmacy and Pharmacology ISSN: 2326-7267 Vol. 3 (8), pp. 001-006, August, 2012. © International Scholars Journals

Full Length Research Paper

Effect of the aqueous seed extract of Persea americana mill (Lauraceae) on the blood pressure of sprague-dawley rats

Ogochukwu N. Anaka, Raymond I. Ozolua* and Stephen O. Okpo

Department of Pharmacology and Toxicology, Faculty of Pharmacy, University of Benin, P. M. B. 1154, Benin City 300001, Nigeria.

Accepted 09 April, 2012

Abstract

The aqueous seed extract (AE) of Persea americana Mill (Lauraceae) is used by some herbal medicine practitioners in Nigeria for the treatment of hypertension. We investigated its effects on the mean arterial pressure (MAP) and Heart Rate (HR) of naïve and 260 mg/kg/day x 10 days pretreated rats. Naïve rats were given bolus injections of (a) - AE (240, 260, 280 mg/kg); (b) - 2 µg/kg of acetylcholine (ACh) + 240, 260, 280 mg/kg of AE; or bolus doses of ACh (1, 2, 4 µg/kg). Results show that 10-day pretreatment significantly reduced MAP (125.7 ± 11.2 vs 92.1 ± 8.5 mm Hg) and HR (274.6 ± 39.3 vs 161.6 ± 11.6 beats/min). Also, acute AE injections significantly decreased MAP from baseline values in naïve rats. The effects of AE on MAP were comparable with those of ACh. Combination of AE with 2 µg/kg of ACh only significantly potentiated the MAP reducing effect of 240 mg/kg of AE. It is concluded that the aqueous seed extract of P. americana reduces BP and HR in normotensive rats. This observation lends credence to its use by herbalists for the management of hypertension.

Key words: Persia americana seed, herbal medicine, blood pressure, heart rate.