Antibacterial, Anti-HIV-1 Protease and Cytotoxic Activities of Aqueous Ethanolic Extracts from Combretum Adenogonium Steud. Ex A. Rich (Combretaceae).

\ud \ud Records have shown that Combretum adenogonium Steud. Ex A. Rich (Combretaceae) is used in traditional medicine systems of several tribes in Tanzania. This study focused on the investigation of antibacterial activity, anti-HIV-1 protease activity, toxicity properties and classes of phytochemicals in extracts from C. adenogonium Steud. Ex A. Rich (Combretaceae) to evaluate potential of these extracts for development as herbal remedies. Dried plant material were ground to fine powder and extracted using 80% aqueous ethanol to afford root, leaf and stem bark extracts. The extracts were assayed for anti-HIV-1 protease activities, antibacterial activities using microdilution methods and cytotoxicity using brine shrimps lethality assay. Screening for major phytochemical classes was carried out using standard chemical tests. All extracts exhibited antibacterial activity to at least one of the test bacteria with MIC-values ranging from 0.31-5.0 mg/ml. Two extracts, namely, root and stem bark exhibited anti-HIV-1 PR activity with IC50 values of 24.7 and 26.5 μg/ml, respectively. Stem bark and leaf extracts showed mild toxicity with LC50 values of 65.768 μg/ml and 76.965 μg/ml, respectively, whereas roots were relatively non-toxic (LC50 = 110.042 μg/ml). Phytochemical screening of the extracts indicated presence of flavonoids, terpenoids, alkaloids, tannins, glycosides and saponins. These results provide promising baseline information for the potential development of C. adenogonium extracts in treatment of bacterial and HIV/AIDS-related opportunistic infections

Acute toxicity, brine shrimp cytotoxicity and relaxant activity of fruits of callistemon citrinus curtis

<p>Abstract</p> <p>Background</p> <p><it>Callistemon citrinus </it>Curtis belongs to family Myrtaceae that has a great medicinal importance. In our previous work, fruits of <it>Callistemon citrinus </it>were reported to have relaxant (antispasmodic) activity. The current work describes the screening of fractions of the crude methanol extract for tracing spasmolytic constituents so that it shall help us for isolation of bioactive compounds. Acute toxicity and brine shrimp cytotoxicity of crude methanol extract are also performed to standardize it.</p> <p>Methods</p> <p>The crude methanol extract was obtained by maceration with distilled water (500 ml) three times and fractionated successively with <it>n-</it>hexane, chloroform, ethyl acetate and <it>n-</it>butanol (300 ml of each solvent). Phytochemical analysis for crude methanol extract was performed. Acute toxicity studies were performed in mice. Brine shrimp cytotoxicity studies were performed to determine its cytotoxicity and standardize it. In other series of experiments, rabbits' jejunum preparations were used in screening for possible relaxant activities of various fractions. They were applied in concentrations of 0.01, 0.03, 0.1, 0.3, 1.0, 3.0, 5.0 and 10.0 mg/ml on spontaneous rabbits' jejunum preparations. In similar fashion, fractions were also tested on KCl (80 mM) -induced contractions. Calcium chloride curves were constructed in K-rich Tyrode's solution. The effects of various fractions were tested on calcium chloride curves at concentrations 1.0, 3.0, 5.0 and 10.0 mg/ml. Curves of verapamil used as reference drug at concentration 0.1 μM and 0.3 μM were also constructed. The curves were compared with their respective controls for possible right shift.</p> <p>Results</p> <p>Methanol extract tested strongly positive for saponins and tannins. However, it tested mild positive for presence of proteins, amino acids, carbohydrates and phenolic compounds. LD₅₀value for crude methanol extract is 476.25 ± 10.3 (470-481, n = 4) mg/ml. Similarly, EC₅₀value for brine shrimp cytotoxicity is 65.5 ± 7.28 (60.8- 69.4, n = 4) mg/ml. All the fractions relaxed the spontaneous and KCl-induced contractions. EC₅₀values (mg/ml) for effects of ethyl acetate fraction on spontaneous and KCl induced contractions are 2.62 ± 0.78 (2.15-3.0, n = 4) and 3.72 ± 0.86 (3.38-4.28, n = 4) respectively. Respective EC₅₀values (mg/ml) for <it>n-</it>butanol fraction are 3.59 ± 0.2(3.07-3.9, n = 4) for spontaneous, and 5.57 ± 0.2 (5.07-6.11, n = 4) for KCl- induced contractions. EC₅₀value for control calcium chloride curve (without extract) is -2.73 ± 0.19 (-2.6 - -2.81, n = 4) while EC₅₀for curves treated with 5.0 mg/ml of chloroform is -2.22 ± 0.02 (-2.16 - -2.3, n = 4). EC₅₀value for ethyl acetate treated (1.0 mg/ml) tissues is -1.95 ± 0.10 (-1.88 - -2.0, n = 4) <it>vs</it>. control EC₅₀= -2.71 ± 0.08 (-2.66 - -2.76, n = 4). All the fractions, except <it>n-</it>hexane, showed a right shift like that of verapamil (EC₅₀= -1.72 ± 0.15 (-1.62 - -1.8, n = 4) vs. Control EC₅₀= -2.41 ± 0.06 (-2.38 - - 2.44, n = 4), a standard drug that blocks voltage operated calcium channels.</p> <p>Conclusion</p> <p>Relaxant constituents were more concentrated in ethylacetate fraction followed by chloroform, <it>n -</it>butanol and aqueous fractions that warrant for its isolation. The crude methanol extract is safe at concentration 250 mg/ml or below and results of brine shrimp cytotoxicity assay imply the plant specie may be a source of cytotoxic agents.</p

Aphrodisiac activity of 50% ethanolic extracts of Myristica fragrans Houtt. (nutmeg) and Syzygium aromaticum (L) Merr. & Perry. (clove) in male mice: a comparative study

BACKGROUND: Spices are considered as sexual invigorators in the Unani System of Medicine. In order to explore the sexual function improving effect of Myristica fragrans Houtt. (nutmeg) and Syzygium aromaticum (L) Merr. & Perry. (clove) an experimental study was conducted in normal male mice. METHODS: The extracts (50% ethanolic) of nutmeg and clove were administered (500 mg/kg; p.o.) to different groups of male Swiss mice. Mounting behaviour, mating performance, and general short term toxicity of the test drugs were determined and compared with the standard drug Penegra (Sildenafil citrate). RESULTS: The extracts of the nutmeg and clove were found to stimulate the mounting behaviour of male mice, and also to significantly increase their mating performance. The drugs were devoid of any conspicuous general short term toxicity. CONCLUSION: The extracts (50% ethanolic) of nutmeg and clove enhanced the sexual behaviour of male mice

Hepatoprotective effects of methanol extract of Carissa opaca leaves on CCl4-induced damage in rat

<p>Abstract</p> <p>Background</p> <p><it>Carissa opaca </it>(Apocynaceae) leaves possess antioxidant activity and hepatoprotective effects, and so may provide a possible therapeutic alternative in hepatic disorders. The effect produced by methanolic extract of <it>Carissa opaca </it>leaves (MCL) was investigated on CCl₄-induced liver damages in rat.</p> <p>Methods</p> <p>30 rats were divided into five groups of six animals of each, having free access to food and water <it>ad libitum</it>. Group I (control) was given olive oil and DMSO, while group II, III and IV were injected intraperitoneally with CCl₄(0.5 ml/kg) as a 20% (v/v) solution in olive oil twice a week for 8 weeks. Animals of group II received only CCl₄. Rats of group III were given MCL intragastrically at a dose of 200 mg/kg bw while that of group IV received silymarin at a dose of 50 mg/kg bw twice a week for 8 weeks. However, animals of group V received MCL only at a dose of 200 mg/kg bw twice a week for 8 weeks. The activities of aspartate transaminase (AST), alanine transaminase (ALT), alkaline phosphatase (ALP), lactate dehydrogenase (LDH) and γ-glutamyltransferase (γ-GT) were determined in serum. Catalase (CAT), peroxidase (POD), superoxide dismutase (SOD), glutathione-S-transferase (GST), glutathione peroxidase (GSH-Px), glutathione reductase (GSR) and quinone reductase (QR) activity was measured in liver homogenates. Lipid peroxidation (thiobarbituric acid reactive substances; TBARS), glutathione (GSH) and hydrogen peroxide (H₂O₂) concentration was also assessed in liver homogenates. Phytochemicals in MCL were determined through qualitative and high performance liquid chromatography (HPLC) analysis.</p> <p>Results</p> <p>Hepatotoxicity induced with CCl₄was evidenced by significant increase in lipid peroxidation (TBARS) and H₂O₂level, serum activities of AST, ALT, ALP, LDH and γ-GT. Level of GSH determined in liver was significantly reduced, as were the activities of antioxidant enzymes; CAT, POD, SOD, GSH-Px, GSR, GST and QR. On cirrhotic animals treated with CCl₄, histological studies showed centrilobular necrosis and infiltration of lymphocytes. MCL (200 mg/kg bw) and silymarin (50 mg/kg bw) co-treatment prevented all the changes observed with CCl₄-treated rats. The phytochemical analysis of MCL indicated the presence of flavonoids, tannins, alkaloids, phlobatannins, terpenoids, coumarins, anthraquinones, and cardiac glycosides. Isoquercetin, hyperoside, vitexin, myricetin and kaempherol was determined in MCL.</p> <p>Conclusion</p> <p>These results indicate that MCL has a significant protective effect against CCl₄induced hepatotoxicity in rat, which may be due to its antioxidant and membrane stabilizing properties.</p

Screening of crude extracts of six medicinal plants used in South-West Nigerian unorthodox medicine for anti-methicillin resistant Staphylococcus aureus activity

BACKGROUND: Six Nigerian medicinal plants Terminalia avicennioides, Phylantus discoideus, Bridella ferruginea, Ageratum conyzoides, Ocimum gratissimum and Acalypha wilkesiana used by traditional medical practitioners for the treatment of several ailments of microbial and non-microbial origins were investigated for in vitro anti-methicillin Resistant Staphylococcus aureus (MRSA) activity. METHODS: Fresh plant materials were collected from the users. Water and ethanol extracts of the shredded plants were obtained by standard methods. The Bacterial cultures used were strains of MRSA isolated from patients. MRSA was determined by the reference broth microdilution methods using the established National Committee for Clinical Laboratory Standards break points. Staphylococcus aureus NCIB 8588 was used as a standard strain. Susceptibility testing and phytochemical screening of the plant extracts were performed by standard procedures. Controls were maintained for each test batch. RESULTS: Both water and ethanol extracts of T. avicennioides, P. discoideus, O. gratissimum, and A. wilkesiana were effective on MRSA. The Minimum Inhibition Concentration (MIC) and Minimum Bactericidal Concentration (MBC) of the ethanol extracts of these plants range from 18.2 to 24.0 mcg/ml and 30.4 to 37.0 mcg/ml respectively. In contrast, MIC range of 30.6 to 43.0 mcg/ml and 55.4 to 71.0 mcg/ml were recorded for ethanol and water extracts of B. ferruginea, and A. conyzoides respectively. Higher MBC values were obtained for the two plants. These concentrations were too high to be considered active in this study. All the four active plants contained at least trace amount of anthraquinones. CONCLUSION: Our results offer a scientific basis for the traditional use of water and ethanol extracts of A. wilkesiana, O. gratissimum, T. avicennioides and P. discoideus against MRSA-associated diseases. However, B. ferruginea and A. conyzoides were ineffective in vitro in this study; we therefore suggest the immediate stoppage of their traditional use against MRSA-associated diseases in Lagos, Nigeria

Preliminary phytochemical screening and In vitro antioxidant activities of the aqueous extract of Helichrysum longifolium DC

<p>Abstract</p> <p>Background</p> <p>Many oxidative stress related diseases are as a result of accumulation of free radicals in the body. A lot of researches are going on worldwide directed towards finding natural antioxidants of plants origins. The aims of this study were to evaluate <it>in vitro </it>antioxidant activities and to screen for phytochemical constituents of <it>Helichrysum longifolium </it>DC. [Family Asteraceae] aqueous crude extract.</p> <p>Methods</p> <p>We assessed the antioxidant potential and phytochemical constituents of crude aqueous extract of <it>Helichrysum longifolium </it>using tests involving inhibition of superoxide anions, DPPH, H₂O₂, NO and ABTS. The flavonoid, proanthocyanidin and phenolic contents of the extract were also determined using standard phytochemical reaction methods.</p> <p>Results</p> <p>Phytochemical analyses revealed the presence of tannins, flavonoids, steroids and saponins. The total phenolic content of the aqueous leaf extract was 0.499 mg gallic acid equivalent/g of extract powder. The total flavonoid and proanthocyanidin contents of the plant were 0.705 and 0.005 mg gallic acid equivalent/g of extract powder respectively. The percentage inhibition of lipid peroxide at the initial stage of oxidation showed antioxidant activity of 87% compared to those of BHT (84.6%) and gallic acid (96%). Also, the percentage inhibition of malondialdehyde by the extract showed percentage inhibition of 78% comparable to those of BHT (72.24%) and Gallic (94.82%).</p> <p>Conclusions</p> <p>Our findings provide evidence that the crude aqueous extract of <it>H. longifolium </it>is a potential source of natural antioxidants, and this justified its uses in folkloric medicines.</p

Antibacterial activity of Artemisia nilagirica leaf extracts against clinical and phytopathogenic bacteria

<p>Abstract</p> <p>Background</p> <p>The six organic solvent extracts of <it>Artemisia nilagirica </it>were screened for the potential antimicrobial activity against phytopathogens and clinically important standard reference bacterial strains.</p> <p>Methods</p> <p>The agar disk diffusion method was used to study the antibacterial activity of <it>A. nilagirica </it>extracts against 15 bacterial strains. The Minimum Inhibitory Concentration (MIC) of the plant extracts were tested using two fold agar dilution method at concentrations ranging from 32 to 512 μg/ml. The phytochemical screening of extracts was carried out for major phytochemical derivatives in <it>A. nilagirica</it>.</p> <p>Results</p> <p>All the extracts showed inhibitory activity for gram-positive and gram-negative bacteria except for <it>Klebsiella pneumoniae, Enterococcus faecalis </it>and <it>Staphylococcus aureus</it>. The hexane extract was found to be effective against all phytopathogens with low MIC of 32 μg/ml and the methanol extract exhibited a higher inhibition activity against <it>Escherichia coli, Yersinia enterocolitica, Salmonella typhi</it>, <it>Enterobacter aerogenes</it>, <it>Proteus vulgaris</it>, <it>Pseudomonas aeruginosa </it>(32 μg/ml), <it>Bacillus subtilis </it>(64 μg/ml) and <it>Shigella flaxneri </it>(128 μg/ml). The phytochemical screening of extracts answered for the major derivative of alkaloids, amino acids, flavonoids, phenol, quinines, tannins and terpenoids.</p> <p>Conclusion</p> <p>All the extracts showed antibacterial activity against the tested strains. Of all, methanol and hexane extracts showed high inhibition against clinical and phytopathogens, respectively. The results also indicate the presence of major phytochemical derivatives in the <it>A. nilagirica </it>extracts. Hence, the isolation and purification of therapeutic potential compounds from <it>A. nilagirica </it>could be used as an effective source against bacterial diseases in human and plants.</p