Effects of MOF6 Fraction from Ethanolic Extract of the Leaves of Moringa oleifera against Sodium Arsenite-Induced Hepatotoxicity in Rats

Moringa oleifera (MO) is a plant of significant medicinal importance. The dried leaves of MO were pulverized, extracted with ethanol and fractionated using column chromatography to provide seven fractions (MOF1-7) with MOF6 having the best preliminary antioxidant potential. Therefore, this study evaluated the hepatoprotective potentials of MOF6 in sodium arsenite (SA)-induced hepatotoxicity in rats. Thirty-five adult male Wistar rats were randomly divided into seven groups of five rats each. Control Group I received normal saline. Groups II and III received 20 mg/kg body weight (bw) of SA for 3 and 6 weeks, respectively. Groups IV and V received 20 mg/kg bw of SA for 3 weeks followed by treatment with 5.0 and 7.5 mg/kg bw of fraction MOF6, respectively, for 6 weeks. Groups VI and VII received only 5.0 and 7.5 mg/kg bw of fraction MOF6, respectively, for 6 weeks. Antioxidant (lipid peroxidation) and biochemical analyses of liver enzymes of all rats were carried out after the completion of experimental procedures. Results showed statistically significant lower mean values (p ≤ 0.05) of malondialdehyde (MDA), acid phosphatase (ACP) and γ-glutamyl transferase (GGT) in rats of Groups IV and V compared with Group III. However, there were statistically significant higher mean values (p ≤ 0.05) of alkaline phosphatase (ALP) in Groups IV and V compared with Groups I and III. In conclusion, these results implied that fraction MOF6 has antioxidant and hepatoprotective potentials. However, results of ALP analyses implied that MOF6 possibly augmented SA-induced hepatotoxicity in rats.

In Vitro Antimicrobial Activity of 80% Methanol Extract and Solvent Fractions of Urtica simensis Hochst. ex. A. Rich. (Urticaceae) Leaves against Pathogenic Bacteria and Fungi

Medicinal plants have been used for the treatment of infectious diseases since a long time. Urtica simensisHochst. ex. A. Rich. is one of the endemic medicinal plants used for the treatment of bacterial and fungalinfections in Ethiopian folklore medicine. The aim of this study was to investigate the antimicrobial activityof 80% methanol extract and solvent fractions of the leaves of U. simensis. The 80% methanol extract wasprepared by maceration and the solvent fractions were obtained by successive fractionation of the 80%methanol extract with chloroform, ethyl acetate, n-butanol and distilled water. The antimicrobial activity ofthe extracts was evaluated on eight bacterial and two fungal species using agar well diffusion method atconcentrations of 200, 400 and 800 mg/ml. Minimum inhibitory concentrations (MICs) were determined bybroth microdilution method. From the gram positive bacteria tested, the most susceptible species wasStreptococcus pneumoniae (MIC of 1.36 mg/ml), while Klebsiella pneumoniae and Aspergillus niger weremost susceptible gram negative bacterial and fungal species with MIC values of 2.54 and 3.13 mg/ml,respectively. The least values of MIC, MBC and MFC were 1.36, 5.21 and 6.25 mg/ml, respectively. Resultsof the present study revealed that the 80% methanol extract and solvent fractions, of the leaves of U.simensis, with the exception of the aqueous fraction, possess activity against the growth of selected pathogenic bacterial and fungal species. Among the solvent fractions, the n-butanol fraction was the most active fraction against the gram positive bacteria tested, while the ethyl acetate fraction was the most active fraction against the other tested organisms. Further studies are needed to isolate the active principles, elucidate the mechanism of antimicrobial action, determine in vivo antimicrobial activity and effect of the extracts on other pathogens including clinical isolates.

Antimalarial Activity of the 80% Methanol Leaf Extract and Solvent Fractions of Stephania abyssinica (Dill. & A. Rich.) Walp. against Plasmodium berghei Infection in Mice

Malaria continues to be a global public health threat. In Africa, malaria accounts for a substantial morbidity and mortality. The emergence of drug resistant malaria parasites and subsequent decrement in effectiveness of current antimalarial medications have complicated malaria control. This urged developing an effective alternative antimalarial agent. Leaves and root of Stephania abyssinica (Dill. & A. Rich.) Walp. is traditionally used for the treatment of malaria in east African countries such as Ethiopia and proved for its in vitro antimalarial efficacy. Hence, this study aimed at evaluating the antimalarial activity of S. abyssinica. Cold maceration technique was employed to prepare the 80% methanol crude extract followed by fractionation using n-hexane, chloroform and ethyl acetate. The in vivo antimalarial property of different dose levels (100, 200 and 400 mg/kg/day) of the hydroalcoholic extract and solvent fractions were investigated using prophylactic and 4-day suppressive mice models, against Plasmodium berghei (ANKA strain). Highest (400 mg/kg) doses of the hydroalcoholic extract and solvent fractions (hexane, chloroform and ethyl acetate) exhibited a statistically significant (p < 0.001) chemosuppressive activities. The chloroform fraction revealed the highest chemosuppresion (55.80%) and chemoprophylactic (57.59%) potency in 4-day suppressive and prophylactic tests, respectively, at 400 mg/kg dose level. Furthermore, 400 mg dose of the chloroform fraction significantly prevented malaria associated haemolysis as compared to vehicle treated group in both prophylactic (p < 0.05) and suppressive (p < 0.01) models. In conclusion, the current study gave evidence that the plant has a potential antimalarial activity against P. berghei, which upholds traditional claims and justifies a need to undertake advanced pharmacological and toxicological investigations.

Anticonvulsant Activity of 80% Methanol Leaf Extract and Solvent Fractions of Buddleja polystachya Fresen. (Buddlejaceae) in Mice

Epilepsy is a chronic non-communicable disease characterized by recurrent seizures. According to 2019 WHO report, it affects about 50 million people globally and nearly 80% of them live in low-and middleincome countries. Current antiepileptic drugs have several limitations including lack of response in significant number of patients and intolerable adverse drug reactions. Buddleja polystachya Fresen. (Buddlejaceae) is a medicinal plant used for the treatment of epilepsy in Ethiopian traditional medicine, where the dried leaves are crushed, mixed with local alcoholic beverage and taken orally. Thus, this study was conducted to evaluate the anticonvulsant activity of the 80% methanol leaf extract and solvent fractions of B. polystachya in mice models of seizure. The dried and powdered leaves of B. polystachya were extracted using cold maceration with 80% methanol (1:5 w/v), and the resulting crude extract was fractionated using chloroform and n-butanol to get chloroform, n-butanol and aqueous fractions. Anticonvulsant activities of B. polystachya crude extract and solvent fractions at doses of 100, 200 and 400 mg/kg were evaluated using pentylenetetrazol (PTZ) and maximal electroshock (MES)–induced seizures in mice (n = 6). In addition, motor coordination effects were assessed using rotarod test. Sodium valproate (200 mg/kg), phenytoin (25 mg/kg) and diazepam (5 mg/kg) were used as standards for PTZ, MES and rotarod tests, respectively. Distilled water or 2% tween 80 was used as negative control. All doses of the crude extract exhibited a significant (p < 0.001) anticonvulsant property in both PTZ and MES tests compared with negative control. Similarly, the n-butanol fraction exerted significant (p < 0.001) anticonvulsant effects in both seizure models. However, the chloroform fraction (200 and 400 mg/kg) showed a significant (p < 0.001) anticonvulsant effect in only PTZ-induced seizure model. The aqueous fraction was devoid of any anticonvulsant activity in both models. The crude extract and fractions did not exert any significant changes in motor coordination. Preliminary phytochemical screening of the crude extract and solvent fractions revealed the presence of flavonoids, phenols, tannins, steroids, terpenoids and saponins. In conclusion, the results of this study indicated that the plant has a promising anticonvulsant activity and could be considered as a potential source to develop new anticonvulsant drug.

Preparation and Characterization of Cellulose and Microcrystalline Cellulose from Sugarcane Bagasse and Assessment of the Microcrystalline Cellulose as a Directly Compressible Excipient

Cellulose, the most abundant biomass material in nature finds wide applications in the pharmaceutical industry. Sugarcane bagasse (SCB) is one of the main agricultural lignocellulose byproducts. The objective of this study was to prepare and characterize native and microcrystalline cellulose (MCC) from SCB and evaluate the MCC as a directly compressible pharmaceutical excipient. Cellulose was extracted from SCB by chlorine-free methods with or without dewaxing. MCC was prepared from the cellulose by hydrolysis using hydrochloric acid, and subsequently oven-dried (OD) or spray-dried (SD). The as-obtained cellulose and MCC were characterized in terms of yield, degree of polymerization (DP), chemical functionality, crystallinity, morphology and thermal stability. The chemical composition, particle size, densities and direct compressibility of MCCs were also determined. Cellulose yields on a dry weight basis were found to be 42.8 ± 1.10% and 43.5 ± 0.5% from non-dewaxed and dewaxed SCB, respectively. Dewaxed SCB cellulose (DSCBC) provided higher yield of MCC (DSCB-MCCOD, 83 ± 0.74%) than non-dewaxed SCB cellulose (SCBC) (SCB-MCCOD; 78 ± 1.07%). The DP of SCBC and DSCBC were 580.56 and 592.75, respectively, while the DP of MCC ranged from 230.10 - 251.40. The FTIR spectra of both cellulose and MCC were similar with that of Avicel PH-101. The degree of crystallinity of the dewaxed cellulose (77.34%) and MCCOD (79.56%) and MCC-SD (81.87%) were higher than non-dewaxed cellulose (74.50%) and MCC-OD (78.11%) and MCC-SD (79.62%). Scanning electron micrographs (SEM) showed a fibrous structure for DSCBC and rod-shaped for DSCB-MCC. Thermogravimetric analysis (TGA) revealed dewaxed products exhibited better thermal stability than non-dewaxed products. All MCC samples exhibited monomodal normal particle size distributions. The Hausner ratio and Carr’s index of DSCB-MCCOD and Avicel PH-101 were not significantly different (p < 0.05) indicating similar flow property and compressibility of the materials, respectively. Also, plain tablets prepared from SCB-MCC showed reasonably high crushing strengths (MCC-SD > MCC-OD), although tablets of Avicel PH-101 showed the highest crushing strengths. Thus, SCB could be an alternative source of cellulose and MCC for pharmaceutical applications.

In vitro Activity of Selected Ethiopian Medicinal Plants against Mycobacterium bovis and Mycobacterium tuberculosis

Tuberculosis is a major global public health problem causing ill-health in millions of the world’s population. The emergence of drug resistant strains is a major challenge to the tuberculosis control programme. Hence, there is an urgent need for the development of new drugs. Herbs could be potential source of novel antituberculosis drugs due to their special attribute as a large source of therapeutic phytochemicals. The objective of this study was to investigate the in vitro antimycobacterial activity of the 80% methanol extracts of Erythrina brucei stem bark, Euphorbia candelabrum latex, Otostegia integrifolia leaf, Rumex abyssinicus root, and the chloroform extract of Vernonia amygdalina leaf on in vitro cultures of strains of Mycobactrium bovis and Mycobactrium tuberculosis. The extracts were obtained through cold maceration and soxhlet extraction, and essential oil was obtained by hydrodistillation. Macrodilution technique was used for determining the minimum inhibitory concentration (MIC) values. The MIC of the chloroform extract of V. amygdalina was 10 mg/ml against the mycobacterial strains tested. The 80% methanol extracts of E. brucei, O. integrifolia and R. abyssinicus were effective against M. bovis only with MIC ranging from 12.50 - 25.00 mg/ml. The oil from O. integrifolia was not active against the tested strains. E. candelabrum and oil from O. integrifolia failed to show antimycobacterial activity. In conclusion, the leaf extract of V. amygdalina is proven to be the most active plant that could be a potential source for antimycobacterial agents for human and bovine tuberculosis. Erythrina brucei, O. integrifolia and R. abyssinicus displayed good antimycobacterial activity against M. bovis suggesting their potential to be sources of new compounds for bovine tuberculosis.

Antidiarrhoeal activity of the 80% methanol root extract of Thalictrum ryhnchocarpum Dill. & A. Rich and its major constituent against castor oil-induced diarrhoea in mice

No Abstract.

In Vitro Antioxidant and Antimicrobial Activities of Methanol Leaf Extract and Fractions of Afzelia bellaHarms (Fabaceae)

Afzelia bella Harms (Fabaceae), a plant widely distributed in Africa, is used in traditional medicine for varied disease conditions including the treatment of topical skin infections. The present study investigated the antimicrobial and antioxidant activities of the methanol extract and various solvent fractions of the leaves of the plant. The methanol leaf extract was partitioned to yield petroleum ether, chloroform, ethyl acetate and residual aqueous fractions. Total phenol and flavonoid contents, radical scavenging activity and ferric reduction antioxidant power (FRAP) were determined by spectrophotometry, while antimicrobial activity and minimum inhibitory concentration (MIC) of the extract and fractions were determined using agar-well diffusion and agar dilution methods, respectively against clinical bacterial isolates of Bacillus subtilis, Escherishia coli, Klebsiella pneumoniae, Staphylococcus aureus, and fungi, Aspergillus flavus, Candida parapsilosis, Microsporium audiounii. Bacillus subtilis was the most susceptible among the bacterial strains tested, while Microsporium audiounii was the most susceptible fungus. The alcoholic extract and all solvent fractions demonstrated a concentration dependent antimicrobial activity with inhibition zone diameter range of 7.5 to 35.0 mm. MIC ranged from 0.1 - 8 mg/ml and activity was highest in ethyl acetate fraction with MIC of 0.1 mg/ml. FRAP ranged from 0.161 - 0.319 mmol Fe2+/g extract and was highest in the ethyl acetate fraction. These results give an indication that A. bella leaf has high antioxidant and antimicrobial activities and support the folkloric claim of the therapeutic potential of the plant. Keywords: antioxidant, antimicrobial, ethnomedicine, Afzelia bella, Fabaceae

Anti-Snake Venom, Anti-Arthritic and Cytotoxic Activities of Tectona grandis L. f. Stem Bark (Lamiaceae)

Tectona grandis L. f. (Lamiaceae) is famous for timber production and has been used in traditional medicine for treating bronchitis, liver-related roubles, urinary discharge amongst other diseases. Methanol extract of the stem bark was investigated for in vivo antiophidian assay against Bitis arietans and Naja nigricollis. Also, the extract and chromatographic fractions were subjected to cytotoxicity tests using tadpole model and antiarthritic assay by proteinase inhibition. Chromatography of crude methanol extract afforded three highly polar vacuum liquid chromatography (VLC) fractions (BVLC-1, BVLC-2 and BVLC-3). BVLC-2 further gave four semi-pure uncharacterized isolates (I, II, III, IV). Only BVLC-2 and BVLC-3 were cytotoxic at 10 - 80 mg/ml, with BVLC-3 being most potent (100% mortality, LC50 40 mg/ml). Concentration-dependent proteinase enzyme inhibition (24 - 71%) at 200 - 1000 μg/ml of BVLC-2 was observed, and this was less (IC50 659.24 μg/ml) than the activity of the standard drug, acetyl salicylic acid. However, neutralization of B. arietans and N. nigricollis snake venoms using methanol extract was not dose-dependent, but the extract atthe least dose, 50 mg/kg offered better protection (75%) on Naja nigricollis envenomed-mice in 48 h. Its activity was comparable to that of the positive antivenin tested at 0.2 mg/kg. These findings justify the folkloric use of T. grandis in the treatment of snake bites, arthritic conditions, and oxidative stress-induced diseases. Keywords: Tectona grandis, methanol extract, anti-snake venom activity, tadpole cytotoxicity, anti-arthritic activity

Preparation and Characterization of Carboxymethylated and Cross-Linked Enset Starch as a Disintegrant in Tablets

Starch and modified starches have been commonly employed as excipient in pharmaceutical industry. The use of non-modified or “native” starch, However, is mostly confined due to limitation in several physicochemical properties. Cross-linked sodium carboxymethyl starch which is also known as sodium starch glycolate is extensively used in fast dissolving tablets to disperse the drugs within short span of time. In this study, enset starch was carboxymethylated and subsequently cross-linked. Carboxymethyl enset starch (CMES) was obtained by reacting enset starch and monochloroacetic acid (MCA) in the presence of sodium hydroxide. CMESs having different degree of substitution (DS) were cross-linked at variousconcentrations (2.5, 5 and 10% w/w) of sodium hexametaphosphate (SHMP) to provide sodium starch glycolate of enset starch (SSG-E). The fourier transform infrared (FTIR) spectra confirmed the presence of carboxymethylated group in the modified starch granules with new band at 1608.52 cm-1. This dually modified enset starch (SSG-E) was evaluated as a potential disintegrant in paracetamol tablets in comparison with commercially available sodium starch glycolate, Disegel. Carboxymethylation was significantly influenced by reaction medium, reaction temperature and reaction time (p < 0.05). CMES with higher DS (0.437 ± 0.03) exhibited higher peak viscosity than CMES with lower DS (0.224 ± 0.01). Despite exhibiting greater swelling power, CMES showed significantly lower pasting viscosity compared to the native starch (p < 0.05). At 2.5% SHMP, the dually modified starch (SSG-E) exhibited significant increase in swelling but its rate of water-uptake was lower than that of Disegel. As the SHMP concentration wasincreased from 2.5 to 5%, the swelling power decreased significantly (p < 0.05). When the concentration was increased to 10% the swelling power increased significantly (p < 0.05). At 2.5% SHMP concentration SSG-E showed a viscosity comparable to that of CMES. As the concentration of SHMP increased to 5 and to 10% w/w, significant decrease in viscosity (p < 0.05) was observed. Compared to the native enset starch (NES), the solubility of SSG-E was more than 4-fold, but its viscosity was much lower than that of CMESs. The SSG-E exhibited lower moisture sorption than CMES but higher sorption than NES. SSG-E showed good flowability, superior swelling power and solubility than NES. The disintegration time (DT) of paracetamol tablets containing SSG-E as a disintegrant was comparable to those tablets with similar concentration of Disegel. At 4% SSG-E, paracetamol tablets exhibited DT less than 1 min. Keywords: carboxymethylation, degree of cross-linking, enset starch, paracetamol tablets, sodium starch glycolate