Aliyu M. Musa

Phenolics-rich fraction of Khaya senegalensis stem bark: Antitrypanosomal activity and amelioration of some parasite-induced pathological changes

Abstract Context: The stem bark of Khaya senegalensis A. Juss (Meliaceae) is currently used for the treatment of trypanosomiasis by traditional practitioners in Nigeria. Objectives: The present study investigated the anti-Trypanosoma brucei brucei activity of phenolics-rich fraction of K. senegalensis (pfks) and its ameliorative effects on trypanosome-induced pathological changes. Materials and methods: The fraction was initially analyzed by gas chromatography-mass spectrometry (GC-MS). A 60 min time course experiment was conducted with various concentrations of the fraction using a 96-well microtiter plate technique and was further used to treat T. brucei infected rats at 100, 200 and 300 mg/kg body weight (BW). Indices of anemia as well as hepatic and renal functions were analyzed in all experimental animals at the end of the experiment. Results: The GC-MS analysis of the pfks revealed that the most abundant phytochemicals are phloroglucinol (40.56%) and 3,4-(dihydroxyphenyl) acetic acid (41.76%). The fraction showed a concentration dependent in vitro antitrypanosomal activity. Interestingly, the fraction completely eliminated the parasites from the bloodstream of infected rats without relapse during the experimental period at the dose of 300 mg/kg BW and also kept the parasites consistently lower at 100 and 200 mg/kg BW than that was recorded in the untreated infected rats. Furthermore, the severity of T. brucei-induced anemia and hepatic damage was significantly (p < 0.05) ameliorated in the 300 mg/kg BW treatment group whereas the parasite-induced renal damage was significantly (p < 0.05) ameliorated in all treatment groups. Conclusion: Data from this study may suggest that phenolics play an important role in the antitrypanosomal activity of K. senegalensis.

Flavonoids with antimicrobial activity from the stem bark of Commiphora pedunculata (Kotschy & Peyr.) Engl.

The first reported investigation into the phytochemical constituents of Commiphora pedunculata led to the isolation of two flavonoids: kaempferol and dihydrokaempferol from the ethyl acetate-soluble fraction of the methanol extract of the stem bark of the plant. The structures of these compounds were characterised by comparing their spectral data including 1D and 2D NMR with those reported in the literature. The two compounds were active against 6 out of 10 tested microorganisms including two resistant strains [methiciline-resistant Staphylococcus aureus and vancomycin-resistant entrococci (VRE)], Candida albicans and Escherichia coli. The zones of inhibition ranged between 24 and 30 mm for both compounds against the microorganisms. The MIC value was as low as 6.25 μg/mL against VRE and Staphylococcus aureus. This is the first report of the isolation of these compounds from the plant.

Central depressant activity of butanol fraction of Securinega virosa root bark in mice

ETHNOPHARMACOLOGICAL RELEVANCE Securinega virosa is a commonly used medicinal plant in African traditional medicine in the management of epilepsy and mental illness. Previous studies in our laboratory showed that the crude methanol root bark extract of the plant possesses significant behavioral effect in laboratory animals. In an attempt to isolate and characterize the biological principles responsible for the observed activity, this study is aimed at evaluating the central depressant activity of the butanol fraction of the methanol root bark extract of Securinega virosa. MATERIALS AND METHODS The medial lethal dose of the butanol fraction was estimated using the method of Lorke. Preliminary phytochemical screening was conducted on the butanol fraction using standard protocol. The behavioral effect of the butanol fraction (75, 150 and 300mg/kg) was evaluated using diazepam induced sleep test, hole-board test, beam walking assay, staircase test, open field test and elevated plus maze assay, all in mice. RESULTS The median lethal dose of the butanol fraction was estimated to be 1256.9mg/kg. The preliminary phytochemical screening revealed the presence of tannins, saponins, alkaloids, flavonoids, cardiac glycosides, similar to those found in the crude methanol extract. The butanol fraction significantly (P<0.001) reduced the mean onset of sleep in mice and doubled the mean duration of sleep in mice at the dose of 75mg/kg. The butanol fraction and diazepam (0.5mg/kg) significantly (P<0.01-0.001) reduced the number of head dips in the hole-board test suggesting sedative effect. The sedative effect of the butanol fraction was further corroborated by its significant (P<0.01-0.001) reduction of the number of step climbed and rearing in the staircase test. The butanol fraction did not significantly increase the time taken to complete the task and number of foot slips in the beam walking assay, suggesting that it does not induce significant motor coordination deficit. Diazepam (2mg/kg), the standard agent used significantly (P<0.01) increased the number of foot slips. In the open field test, the butanol fraction significantly reduced the number of square crossed as well as the number of rearing. However, the butanol fraction did not significantly alter the behavior of mice in the elevated plus maze assay, while diazepam (0.5mg/kg) significantly (P<0.05) increased the time spent in the open arm and reduced the number of closed arm entry. CONCLUSION The findings of this study suggest that the butanol fraction of Securinega virosa root bark contains some bioactive principles that are sedative in nature.

A novel antimicrobial flavonoid from the stem bark of Commiphora pedunculata (Kotschy & Peyr.) Engl.

A new flavonoid, 2-(3,5-dihydroxy-4-methoxy-phenyl)-3,5-dihydroxy-8,8-dimethyl-2,3-dihydro-8H-pyrano[3,2]chromen-4-one, together with previously reported epicatechin was isolated from the ethyl acetate soluble fraction of the methanol extract of the stem bark of Commiphora pedunculata. The structures of these compounds were elucidated based on extensive analysis of their spectral data, including 1 and 2D NMR. The compounds were active against 9 out of 12 tested microorganisms including a resistant strain; vancomycin-resistant entrococci (VRE), Escherichia coli, Staphylococcus aureus and Candida albicans. The zones of inhibition ranged between 22 and 34 mm against the microorganisms. The minimum inhibitory concentration was as low as 6.25 μg/mL against Shigella dysentriae, Bacillus cereus and S. aureus while the minimum bactericidal concentration was as low as 50 μg/mL against Pseudomonas aeruginosa, VRE and C. albicans. This is the first report of the isolation of the compound.

Chemical composition and antimicrobial activity of hexane leaf extract of Anisopus mannii (Asclepiadaceae).

Objective: The aim was to determine the chemical constituents and antimicrobial activity of the hexane leaf extract of Anisopus mannii against a wide range of human pathogenic microorganisms. Methods: The chemical constituents of the hexane leaf extract was determined using gas chromatography-mass spectrometry (GC-MS) analysis; and the antimicrobial activity was evaluated on “standard strains”, clinical susceptible and resistant bacterial and fungal isolates using the disc diffusion and broth microdilution methods. Results: GC-MS analysis of the hexane leaf extract revealed 32 compounds, representing 73.8% of the identified components. The major compounds were hexadecanoic acid, ethyl ester (34%), oxirane, hexadecyl- (11%) and 9, 12, 15-octadecatrienoic acid, ethyl ester, (Z, Z, Z) (9.6%). Results from the antimicrobial activity demonstrated higher inhibition zones against Bacillus cereus (29 mm), followed by Streptococcus pyogenes (28 mm). Other notable inhibitions were observed with Enterococcus faecalis (27 mm), Proteus vulgaris (26 mm) and MRSA (25 mm). The MIC values ranged from 0.625 mg/mL to 1.25 mg/mL while the MBC/MFC values ranged from 2.5 mg/mL to 5.0 mg/mL. Conclusion: These results support the traditional use of the plant and demonstrate the huge potential of A. mannii as a source of antimicrobial compounds.

Effects of α-tocopherol on the in vivo antitrypanosomal effects of phenolics-rich fraction of Khaya senegalensis stem bark

Abstract Objective To investigate the effects of combined administration of a low dose of a phenolics-rich fraction of Khaya senegalensis (PFKS) stem bark with α-tocopherol on Trypanosoma brucei brucei (T. brucei brucei) infection. Methods Rats were divided into five groups of six animals, namely, normal control, uninfected but treated with PFKS and α-tocopherol, infected control, infected and treated with PFKS and α-tocopherol (ITTF) and infected treated with diminazine aceturate. Rats in infected control, ITTF and infected treated with diminazine aceturate were infected with T. brucei brucei while the animals in uninfected but treated with PFKS and α-tocopherol and ITTF were treated with a combination of PFKS (100 mg/kg body weight) and α-tocopherol (100 mg/kg body weight) for 8 days. At the end of the experiment, indices of anemia as well as hepatic and renal functions were analysed. Results The combined treatment significantly (P Conclusions Combination of a low dose of PFKS stem bark and α-tocopherol could be a therapeutically active regimen against animal trypanosomiasis.

Anti-proliferative study and isolation of Ochnaflavone from the ethyl acetate-soluble fraction of Ochna kibbiensis Hutch & Dalziel

Abstract Anti-proliferative activity of the ethyl acetate fractions of Ochna schweinfurthiana F. Hoffm. and Ochna kibbiensis Hutch. and Dalziel methanol leaf extracts were investigated against glioblastoma multiforme (GBM U-1242 MG) cell line. O. kibbiensis significantly (p < 0.001) and dose dependently (IC50 = 25.74 μg/mL) reduced cell count. At 125 μg/mL, O. kibbiensis extract reduced cell count by about 92% compared to the untreated control. On the other hand, at 125 μg/mL, O. schweinfurthiana extract reduced cell count only by 20%, indicating a much weaker activity (IC50 = 823.51 μg/mL). Following from the result obtained, ethyl acetate fraction of O. kibbiensis was subjected to chromatographic purification. This led to the isolation of ochnaflavone; the structure of the isolated compound was identified by analysis of its nuclear magnetic resonance (NMR) spectral data and comparison with data in the literature. Although the isolated ochnaflavone could not be tested for anti-proliferative activity due to insufficient quantity, the obtained results indicate the presence of bioactive anti-GBM principles in O. kibbiensis.

A new Antimicrobial Prenylated Benzo-lactone from the Rhizome of Cissus cornifolia

Background: Medicinal plants remain one of the largest reservoirs of new bioactive compounds. In this study, a new prenylated benzo-lactone (4, 6-dihydroxy-5-methoxy-3-(1, 2, 3, 4, 5-pentahydroxypentyl)-2-benzofuran-1(3H)-one) was isolated from the acetone extracts of the rhizome of Cissus cornifolia. The antimicrobial activity of the compound was evaluated against some microorganisms including Staphylococcus aureus, Salmonella typhi, and Candida albicans. Materials and Methods: The acetone extracts of the rhizome of C. cornifolia was separated and purified by various chromatographic techniques. The structure of the isolated compound was characterized by analysis of spectral data including one and two-dimensional nuclear magnetic resonance. Results: The isolated compound was characterized as (4, 6-dihydroxy-5-methoxy-3-(1, 2, 3, 4, 5-pentahydroxypentyl)-2-benzofuran-1(3H)-one), it showed activity against 6 out of 10 tested clinical isolates of some microorganisms including S. aureus, S. typhi, and C. albicans. The inhibition zones ranged between 17 mm and 25 mm. The inhibition zones observed compare favorably with the positive control used. Conclusion: The compound could serve as a lead for the development of more potent antimicrobial agent. To the best of our knowledge, this is the first report of the isolation and characterization as well as antimicrobial screening of the compound.