Phytochemical, anti-inflammatory and anti-trypanosomal properties of Anthocleista vogelii Planch (Loganiaceae) stem bark.

ETHNOPHARMACOLOGICAL RELEVANCE: Anthocleista vogelii Planch (Loganiaceae) is used in African Traditional Medicine for the treatment of pain and inflammatory disorders as well as sleeping sickness. AIM OF THE STUDY: To determine the in vivo anti-inflammatory and in vitro anti-trypanosomal activities of the extracts of A. vogelii stem bark and identify the phytochemical classes of the fractions responsible for the activities. MATERIALS AND METHODS: The in vivo anti-inflammatory activity of the extracts was evaluated using the egg albumin-induced rat paw oedema model while the in vitro anti-trypanosomal activity was assessed on Trypanosoma brucei brucei. The in vitro cytotoxicity was assessed on HeLa (human cervix adenocarcinoma) cell line. RESULTS: The methanolic extract of A. vogelii stem bark, with 11.2% yield, gave LD50 > 5000 mg/kg. The n-hexane fraction of the extract contains steroids, terpenes and fatty acids and yielded non-cytotoxic terpenoidal column fraction with anti-trypanosomal IC50 of 3.0 µg/mL. The ethylacetate fraction at 100 mg/kg dose significantly (p < 0.05) provoked 37.8, 62.5 and 69.7% inhibition of oedema induced by egg-albumin at the second, fourth and sixth hours respectively. CONCLUSION: The study demonstrated that the anti-inflammatory and anti-trypanosomal activities of A. vogelii are probably due to non-cytotoxic terpenoids and validated the traditional use of A. vogelii in the treatment of inflammation and sleeping sickness.

Medicinal plants used by the people of Nsukka Local Government Area, south-eastern Nigeria for the treatment of malaria: An ethnobotanical survey.

ETHNOBOTANICAL RELEVANCE: Malaria is a serious public health problem especially in sub-Saharan African countries such as Nigeria. The causative parasite is increasingly developing resistance to the existing drugs. There is urgent need for alternative and affordable therapy from medicinal plants which have been used by the indigenous people for many years. AIM OF STUDY: This study was conducted to document the medicinal plant species traditionally used by the people of Nsukka Local Government Area in south-eastern Nigeria for the treatment of malaria. METHODS: A total of 213 respondents, represented by women (59.2%) and men (40.8%), were interviewed using a semi-structured questionnaire. The results were analysed and discussed in the context of previously published information on anti-malarial and phytochemical studies of the identified plants. RESULTS: The survey revealed that 50 plant species belonging to 30 botanical families were used in this region for the treatment of malaria. The most cited families were Apocynaceae (13.3%), Annonaceae (10.0%), Asteraceae (10.0%), Lamiaceae (10.0%), Poaceae (10.0%), Rubiaceae (10.0%) and Rutaceae (10.0%). The most cited plant species were Azadirachta indica (11.3%), Mangifera indica (9.1%), Carica papaya (8.5%), Cymbopogon citratus (8.5%) and Psidium guajava (8.5%). CONCLUSION: The present findings showed that the people of Nsukka use a large variety of plants for the treatment of malaria. The identified plants are currently undergoing screening for anti-malarial, toxicity and chemical studies in our laboratory.

Antidiabetic Activity of Extract and Compounds from an Endophytic Fungus Nigrospora oryzae.

The fungal extract as well as the 3 biosynthetic compounds, (S)-(+)-2-cis-4-trans-abscisic acid (1), , 7'-hydroxy-abscisic acid (2) and 4-des-hydroxyl altersolanol A (3) from the endophytic fungus, Nigrospora oryzae, isolated from Combretum dolichopetalum leaf were investigated for their antidiabetic potential.The antidiabetic activity was determined in alloxan-induced diabetic mice by monitoring their fasting blood sugar for 9 h.The extract and the compounds (1-3) significantly (p<0.001) reduced the fasting blood sugar of the diabetic mice.The present study has shown that the biosynthetic products of the endophytic fungus, N. oryzae, exhibited strong antidiabetic activity. It has further shown that endophytic fungi could be an alternative source of novel compounds for management of diabetes.

Antidiabetic activity of the chemical constituents of Combretum dolichopetalum root in mice.

The root of Combretum dolichopetalum (Combreatacea) is used in ethnomedicine for the management of diabetes mellitus. Though some compounds have been isolated from it, the antidiabetic principles have not been identified. The present study was designed to evaluate the chemical constituents from the root of C. dolichopetalum with a view to identifying the antidiabetic principles. The constituents include the alkaloids, echinulin (1) and arestrictin B (2), the terpenoids, arjunolic acid (3) and 4'-dihydrophaseic acid (4) as well as the phenolic acids, ellagic acid (5) and 3, 4, 3'-tri-O-methylellagic acid (6). Twenty eight mice (in seven groups, n = 4) were made diabetic using alloxan monohydrate (i.p., 120 mg/kg) and treated orally with either the vehicle (control group), any of the constituents or glibenclamide (standard drug). The fasting blood glucose of the diabetic animals was monitored for nine hours. Results showed that all the chemical constituents (1-6) exhibited significant (p < 0.05) antidiabetic activity comparable to glibenclamide. The alkaloids exhibited the most profound antidiabetic activity. The present study has thus identified the antidiabetic principles of C. dolichopetalum root as echinulin, arestrictin B, arjunolic acid, 4'-dihydrophaseic acid, ellagic acid and 3, 4, 3'-tri-O-methylellagic acid. The study has further validated the ethnomedicinal use of the root of C. dolichopetalum in diabetes.

Bioactive Phenylpropanoids, Phenolic Acid and Phytosterol from Landolphia owariensis P. Beauv Stringy Seed Pulp.

Landolphia owariensis P. Beauv is economically important for latex/rubber and folklore medicine. Its stringy seed pulp is freely eaten by humans and animals. Thus, L. owariensis stringy seed pulp was extracted serially with hexane and acetone to isolate and characterize its active pharmaceutical ingredients. Solvent/solvent partition and chromatographic separations afforded four bioactive compounds, (E)-3-(3,4-Dihydroxylcinnamoyl)quinic acid [(E)-Chlorogenic acid], I; (E)-3-(3,4-Dihydroxylcinnamoyl)quinic acid methyl ester [(E)-Chlorogenic acid methyl ester], II; 3,4-Dihydroxylbenzoic acid, (Protocatechuic acid), III; and 22,23-Dihydrostigmaster-3ß-ol (3ß-Sitosterol) (IV). Structures of I, II and III were assigned by combinations of high-performance liquid chromatography-ultraviolet-visible spectroscopy, 1D and 2D nuclear magnetic resonance spectroscopy, high-performance liquid chromatography-mass spectrometry and reference to published literatures, while compound IV was identified by chemical methods and gas chromatography-mass spectrometry. The phenylpropanoids and phenolic acid (compounds I, II and III) are notable standard antioxidants with confirmed hepatic-protective activity and other exciting biological activities. Compound IV has been reported to possess anti-inflammatory activity, anti-colon cancer action and a cholesterol-lowering effect. The described compounds are important medicinal constituents of L. owariensis stringy seed pulp, and this is the first major report on the phytochemistry of L. owariensis P. Beauv.

Metabolites from Combretum dolichopetalum and its associated endophytic fungus Nigrospora oryzae--Evidence for a metabolic partnership.

A new altersolanol derivative, 4-dehydroxyaltersolanol A (9), along with two known sesquiterpenoids, (S)-7'-hydroxyabscisic acid (7) and (S)-abscisic acid (8) were obtained from the endophytic fungus, Nigrospora oryzae, isolated from leaves of Combretum dolichopetalum. The host plant yielded six known compounds including ellagic acid (1), 3, 3', 4-tri-O-methylellagic acid (2), arjunolic acid (3), 4'-dihydrophaseic acid (4), echinulin (5) and arestrictin B (6). Close structural similarities with regard to compounds 4, 7 and 8 were observed between the metabolites from the host plant and those of the endophytic fungus. Furthermore compounds 5 and 6 are related to alkaloids isolated from N. oryzae previously thus stressing the notion that some of the isolated plant metabolites may actually be of fungal origin. The structures of the isolated compounds were established by spectroscopic methods including 1D, 2D NMR, MS, and by comparison with the literature. 4-Dehydroxyaltersolanol A (9) and 3, 3', 4-tri-O-methylellagic acid (2) showed cytotoxicity against L5178Y mouse lymphoma cells with IC50 values of 9.4 and 29.0 µM, respectively.

A new antibacterial benzophenone glycoside from Psidium guajava (Linn.) leaves.

Bioactivity-guided fractionation of methanol extract from the leaves of Psidium guajava L. (Myrtaceae) yielded a new benzophenone glycoside, Guajaphenone A (2) together with two known compounds, Garcimangosone D (1) and Guaijaverin (3). Their structures were elucidated by analysis of spectroscopic data including 1D and 2D NMR and electrospray ionisation mass spectrometry (ESI-MS). The isolated compounds were screened against standard strains of Gram-positive and Gram-negative bacteria using broth dilution assay method, and the MIC values determined and compared with reference antibiotic ceftriaxone. They were found to have significant antibacterial activities against Escherichia coli and Staphylococcus aureus with all of them showing better activities against S. aureus, but displaying weaker activities, in comparison to ceftriaxone. However, despite reduced effect of these compounds against the organisms, this work opens the perspective to use these molecules as 'leads' for the design of novel and selective drug candidates for some tropical infectious diseases.

Antioxidative polyphenols from Nigerian mistletoe Loranthus micranthus (Linn.) parasitizing on Hevea brasiliensis.

Two new phenolic glycosides, linamarin gallate (1) and walsuraside B (2), together with nine known compounds, catechin (3), epicatechin (4), epicatechin 3-O-gallate (5), epicatechin 3-O-(3-O-methyl)gallate (6), epicatechin 3-O-(3,5-O-dimethyl)gallate (7), epicatechin 3-O-(3,4,5-O-trimethyl)gallate (8), quercetin 3-O-ß-d-glucopyranoside (9), rutin (10), and peltatoside (11), were isolated from the leafy twigs of Nigerian mistletoe Loranthus micranthus (Linn.) parasitic on Hevea brasiliensis. Compound 1 was characterized as an unusual cyanogenic glycoside, while compound 8 was isolated for the first time from a natural source. This is the first report of a cyanogenic glycoside from mistletoes. The structures of the new compounds were unambiguously elucidated by 1D ((1)H, (13)C), 2D NMR (COSY, HSQC, and HMBC) and by mass spectroscopy. The antioxidant activities of the isolated compounds (1-11) were evaluated using the 2, 2-diphenyl-1-picrylhydrazyl (DPPH) assay.

Antimotility effects of extracts and fractions of Eastern Nigeria mistletoe (Loranthus micranthus Linn).

OBJECTIVE: To evaluate the antimotility activity of Eastern Nigerian mistletoe[Loranthus micranthus (L. micranthus) Linn] parasitic on six different host trees viz. Baphia nitida, Persia americana, Kola accuminata, Irvingia gabonensis, Citrus simensis and Pentacletra macrophylla (P. mycrophylla). METHODS: The antimotility of the methanol extracts and solvent fractions were evaluated in castor oil induced diarrheoa in rats. RESULTS: The methanol extracts (200 mg/kg, i.p.) inhibited defeacation significantly (P < 0.05) 4 h after administration (75.73% to 93.33%) more than that of atropine sulphate (2 mg/kg, i.p.) which inhibited defeacation by 80.0%. The methanol extract (200 mg/kg, i.p.) of L. micranthus parasitic on P. mycrophylla exhibited significant (P<0.05) inhibition in gastrointestinal transit (67.6%) more than that of atropine sulphate (2 mg/kg, i.p.) which inhibited gastrointestinal transit by 26.4%. The solvent fractions of L. micranthus parasitic on P. mycrophylla at dose levels of 150 mg/kg inhibited significantly the gastrointestinal transit of mice. Fraction F(5) exhibited inhibitory activity which was comparable to loperamide (73.3%). CONCLUSION: The methanol extract of L. micranthus parasitic on P. macrophylla exhibits higher antimotility activity that other extracts. The solvent fractions could serve as source of novel antimotility agents.

Phytochemical analysis, hepatoprotective and antioxidant activity of Alchornea cordifolia methanol leaf extract on carbon tetrachloride-induced hepatic damage in rats.

OBJECTIVE: To investigate the hepatoprotective and antioxidant activities of Alchornea cordifolia (A. cordifolia) leaf extract. METHODS: Various solvent fractions of the methanol extract of the leaf of the plant A. cordifolia Mull. Arg (Fam: Euphorbiaceae) were evaluated for hepatoprotective activity by carbon tetrachloride-induced liver damage in rats. The degree of protection was measured by using biochemical parameters such as serum glutamate oxalate transaminase (SGOT/AST), serum glutamate pyruvate transaminase (SGPT/ALT), alkaline phosphatase (ALP) and total bilirubin. The in vitro antioxidant activity of the extract was also evaluated by the 1, 1-diphenyl- 2-picrylhydrazyl (DPPH) free radical scavenging assay. The extract was subjected to preliminary phytochemical screening. RESULTS: The ethyl acetate and chloroform fractions, at a dose of 300 mg/kg, produced significant (P<0.05) hepatoprotection by decreasing the activities of the serum enzymes and bilirubin while there were marked scavenging of the DPPH free radicals by the fractions. The effects were comparable to those of the standard drugs used for the respective experiments, silymarin and ascorbic acid. Alkaloids, flavonoids, saponins and tannins were detected in the phytochemical screening. CONCLUSION: From this study, it was concluded that the plant of A. cordifolia possesses hepatoprotective as well as antioxidant activities and these activities reside mainly in the ethyl acetate and acetone fractions of methanol leaf extract.

Anti-inflammatory and membrane-stabilizing stigmastane steroids from Alchornea floribunda leaves.

Alchornea floribunda (Euphorbiaceae) leaves are widely used in African ethnomedicine for the management of acute and chronic inflammatory disorders. In the present study, bioactivity-guided fractionation led to the isolation of two known (1 and 3) and one new (2) stigmastane steroids from the hexane extract of Alchornea floribunda leaves. The anti-inflammatory activities of these compounds were evaluated using IN VITRO and IN VIVO animal models. The compounds 1, 2, and 3 at 50 and 100 microg/ear significantly (p < 0.05) inhibited xylene-induced ear edema in mice in a dose-dependent manner. The topical anti-inflammatory effect of 1 and 2 are significantly (p < 0.05) higher than that of indomethacin and prednisolone. At 20 mg/kg (i. p.), all the compounds significantly (p < 0.05) inhibited acute inflammation induced by subplantar injection of egg albumen in rats. Compound 1 exhibited an anti-inflammatory effect (50.9 % edema inhibition) comparable (p < 0.05) to that of prednisolone (48.0 % edema inhibition) at 3 h. Compounds 1, 2, and 3 (50 microg/mL) significantly (p < 0.05) inhibited heat-induced haemolysis of human erythrocytes in vitro, but had no effect on hypotonicity-induced hemolysis. The compounds were elucidated as (24R)-5alpha-stigmast-3,6-dione ( 1), 5alpha-stigmast - 23-ene-3,6-dione ( 2), and 3beta-hydroxy-5alpha-stigmast-24-ene ( 3) by spectral analysis. The results of this study show that these compounds may, in part, account for the anti-inflammatory effect of Alchornea floribunda leaves. This is the first report on the isolation and structure elucidation of these anti-inflammatory steroids from Alchornea floribunda leaves.