Hypoglycaemic and amylase inhibitory activities of leaves of Spondias mombin Linn.

Suppressing the production of glucose by inhibiting a-amylase / a-glucosidase activity is one of the therapeutic approaches for decreasing postprandial hyperglycaemia and a strategy for evaluating antidiabetic activity. We investigated leaves of Spondias mombin because our previous ethnobotanical survey showed that it is used by traditional healers to manage diabetes in South West Nigeria. We report a bioactivity-guided study of S. mombin using glucose loading (1 g/kg) alloxan-induced diabetic rats and inhibition of a-amylase as basis for isolation of active constituents. Hyperglycaemia was induced in albino rats and blood glucose levels monitored for 180 mins using a glucometer. Powdered leaves were macerated with 80% Methanol. The active extract was fractionated on column chromatography packed with silica gel G6OA eluting with gradient mixtures of pet. ether and ethylacetate. The most active a-amylase inhibiting fraction was purified on thin layer chromatography (TLC) and pure compound identified by spectroscopy. Peak decrease in blood glucose of 41.4% (p < 0.05) was recorded after 60 mins. This activity-guided study produced an active TLC band (69.8% amylase inhibition, p < 0.05) from which a-sitosterol was characterized as the main inhibitor. This is first report of hypoglycaemic and amylase inhibitory activities of S. mombin. The role of phytosterols in control of diabetes mellitus is discussed. This study justifies the ethnopharmacological use of this species in recipes for management of diabetes mellitus.

Ethnobotanical studies of medicinal plants used in the management of diabetes mellitus in South Western Nigeria.

This survey was carried out in targeted areas of South West Nigeria in order to inventory plants used by traditional healers in the area for the management of diabetes mellitus. One hundred traditional healers who know and use medicinal plants for treating diabetes mellitus were interviewed. The inventory contains scientific, vernacular, common names of the plants used and method of preparation. Thirty-one plants commonly used by traditional healers in the region were identified. The survey shows plants from the Rutaceae, Leguminosae and Cucurbitaceae families are commonly used by traditional healers in South West Nigeria for the treatment of diabetes mellitus.

Characterisation of ingenol: an inflammatory diterpene from some Nigerian Euphorbia and Elaeophorbia species.

Inflammatory latices of Euphorbia deightonii, Euphorbia desmondi, Elaeophorbia drupifera and Elaeophorbia grandiflora were found to contain ingenol as the parent alcohol of the diterpene esters. The chemotaxonomic significance of the occurrence of ingenol in the genus Elaeophorbia is discussed.

Screening extracts of Euphorbia garuana N.E.Br. for in-vitro cytotoxicity.

Two biological assays utilising in-vitro uptake of 3H-thymidine into TLX/5 lymphoma and rat basophilic leukaemia cells have been used for rapid detection and subsequent isolation of active compounds from the latex of Euphorbia garuana (Euphorbiaceae). Two potent esters were characterized from the latex of E. garuana reportedly used in traditional medicine for the treatment of certain forms of cancer.

Antimicrobial screening of Bridelia, micrantha, Alchormea cordifolia and Boerhavia diffusa.

This report is on the antimicrobial potential of Bridelia micrantha, Alchornea cordifolia and Boerhavia diffusa sourced from traditional healers through an ethnobotanical survey of antiinfective plants in Egbado South in Ogun State, Nigeria. Extracts of B. micrantha and A. cordifolia exhibited significant inhibitory activity against the pathogenic organisms. In some cases, the antibacterial activity was comparable to those of ampicillin and gentamycin. However, only the leaf of A. cordifolia showed reasonable antifungal activity when compared with Trosyd. The study shows that there is justification for the use of these medicinal plants in traditional medicine.

Phytochemical and microscopic evaluation of cultivated Datura innoxia miller.

Using a sensitive analytical method, the total alkaloid content of Datura innoxia cultivated in Ibadan is reported at different stages of growth. Furthermore, the total hyoscine content of D. inoxia has been shown to peak during the harmattan season and to be at its lowest in the rainy season in Ibadan. The diagnostic microscopic features of this little studied species is also described.

Seasonal accumulation of anthraquinones in leaves of cultivated Cassia podocarpa Guill et Perr.

Seasonal variations and spectrophotometric determination of anthraquinones in cultivated Cassia podocarpa are presented. The study shows that combined anthraquinones are concentrated in the leaves at peak flowering (2.43%) and lowest in the bark (0.21%). Anthraquinone glycosides reached peak levels during the months of October to March (dry season), the maximum being recorded during January to March. There was significant drop in glycosidic content during the period April to September (rainy season). There was slight increase in concentration of aglycones during the rainy season which may be due to inter-conversion of some glycosides to the aglycones. However, the free aglycone content is much lower than the glycosides. This is desirable for optimum laxative activity and reduced toxicity. This study is significant because it provides useful information on the seasonal distribution of anthraquinones and the best period for harvesting leaves of C. podocarpa for drug development. The inclusion of C. podocarpa in the African Pharmacopoeia will, no doubt, enhance its commercialization as laxative and for its antimicrobial effect.

Isolation of an anti-tumour terpenoid from stem bark of Spondianthus preussii var. preussii Engl.

We report a biologically monitored phytochemical separation of stem bark of Spondianthus preussii var. preussii against a panel of human cancer cell lines in vitro and the P-388 murine lymphocytic leukemia cells in culture. An ethylacetate extract of the stem bark exhibited selective cytotoxicity against human melanoma (ED50 = 10.0 ug/ml). Further activity-guided fractionation of the ethylacetate extract by flash chromatography and subsequent purification on preparative thin layer chromatography led to the identification of a lupane-type triterpene, 3beta-hydroxy-20(29)--lupenoic acid, by spectroscopic methods. This is the first report of the occurrence of this compound in S. preussii var. preussii. It is also the first time this triterpene is being shown to exhibit in vitro anti-tumor activity against human melanoma (ED50 = 2.4 ug/ml). This compound could be a promising bioactive natural product since it has been previously reported to exhibit a range of biological activities including in vivo and in vitro antiplasmodial activity and it is not toxic.

Seasonal variations of hydroxyanthraquinone content of cultivated Cassia spectabilis DC.

Seasonal variations and spectrophotometric estimation of the anthraquinone content of cultivated Cassia spectabilis DC are presented. Concentrations of anthraquinones peaked in the leaves (1.03%) at flowering Significant (P < 0.05) variations in anthraquinone content were observed in the cultivated species. Anthraquinones reached peak levels during the months of September to January (dry season). There was a significant (P < 0.05) drop in anthraquinone content during the rainy season. The diagnostic microscopic features of this little studied species are also described. This study has provided vital information on the best period of harvest and seasonal distribution of anthraquinones in the leaves of the species.

Variation of total hyoscine content of cultivated Datura metel Linn.

A titrimetric method is described for rapid assay of hyoscine content of organs of locally cultivated Datura metel Linn. Raw materials required (approximately 1.5 gm) are much less than those required for conventional percolation processes. Using the procedure, the flowers have been shown to be richest in hyoscine, only minimal levels of alkaloids being detected in the fruits. Furthermore, the total alkaloid content of D. metel has been shown to peak in the hot dry season, and at its lowest during the rainy season in Ibadan.

Microscopic evaluation and seasonal variations of anthraquinone glycosides of cultivated Cassia fistula Linn.

In this report, we present the results of the microscopy, seasonal variations and spectrophotometric estimation of hydroxy-anthraquinone glycosides of culitivated Cassia fistula Linn. The total glycoside contents ofthe morphological parts of this species at different stages of growth are also presented. The study shows that anthraquinone glycosides are concentrated in the leaves (1.75%) and flowers (1.58%) at peak flowering. Notable seasonal variations were observed in the cultivated species. Hydroxyanthraquinones reached peak levels druing the months of September (1.08%) and October (2.20%). There was a significant drop (P < 0.05) in glycoside content during most part of the rainy season. It has been established that anthraquinone glycosides, rather than the aglycones, are the active forms and hence an estimation of the total glycoside content of a sample is a reliable indication of biological activity. The advantages of using the natural anthraquinone laxative when the glycoside content is highest are discussed. The study has provided useful information on the best period for harvesting the morphological parts of C. fistula for drug development.

Alpha-amylase inhibitory activity of two Anthocleista species and in vivo rat model anti-diabetic activities of Anthocleista djalonensis extracts and fractions.

ETHNOPHARMACOLOGICAL RELEVANCE: Anthocleista djalonensis (A. Chev) and Anthocleista vogelii Planch are plants being used in West Africa traditionally to treat various diseases such as malaria, hernia, hypertension, stomach aches, hemorrhoids, syphilis, and diabetes. Diabetes causes about 5% of all deaths globally each year. Chemotherapeutic agents such as biguanides, sulfonylureas, and thiozolidinediones are available for the treatment of diabetes, however, they have undesirable side effects. The need for newer, more effective and less toxic drugs is imperative and the biodiversity of Nigeria has a high potential for drug discovery based on plants used in the ethnomedicine. AIM OF THE STUDY: To investigate the leaves, stem bark and roots of these plants for their probable alpha-amylase inhibitory activities and establish their anti-diabetic activities. The overall goal is do bioassay-guided fractionation and isolation of active anti-diabetic compounds. MATERIALS AND METHODS: Powdered samples (leaves, stem bark and roots) macerated with 80% aqueous methanol were evaluated in vitro using alpha-amylase inhibitory assay while in vivo investigations were carried out on hyperglycemic rats. Diabetes was induced in albino rats by an intraperitoneal injection of alloxan monohydrate (80mg/kg). Plant extracts (1g/kg) were given orally for 7 days, while blood glucose levels were monitored using a one touch glucometer. The crude methanol extracts found to be most active were further partitioned into hexane and ethyl acetate fractions which were also tested in vivo on the diabetic animals. RESULTS: The leaves and stem bark crude methanol extracts of Anthocleista djalonensis gave comparable α-amylase inhibition of 73.66% and 72.90%, respectively which were quite higher than the 38.93% and 22.90% of the same plant parts given by Anthocleista vogelii. The crude stem bark extract of Anthocleista djalonensis exhibited significant peak blood glucose reduction on day 6 (72.59%, p<0.05) which was higher than the leaves or roots which gave 45.73% and 47.46% (p<0.05), respectively The stem bark ethyl acetate fraction of Anthocleista djalonensis gave reduction in blood glucose level of 60.86% (p<0.05). CONCLUSION: From our results, the leaves, stem bark and whole root of both plants exhibited α-amylase inhibitory activities with Anthocleista djalonensis also showing good anti-diabetic activities in vivo indicating that they contain active principles for the management of diabetes. There is justification for the use of the plants traditionally to manage diabetes.

Wound healing effect of Flabellaria paniculata leaf extracts.

AIM OF THE STUDY: This study evaluated wound healing activity of the chloroform and aqueous fractions of the methanolic extract of Flabellaria paniculata leaf on infected wounds in rats as a follow up to an initial study of the crude extract. MATERIALS AND METHODS: Wounds were inflicted on Wistar rats using excision model. Local infection was introduced into rat abdominal wounds with Staphylococcus aureus and Pseudomonas aeruginosa using a 10(8)cells/ml inoculum. Rate of wound healing was assessed by contraction and period of epithelization. RESULTS: Chloroform fraction exhibited significant wound healing potency (p<0.05) as compared with controls. The test drug achieved 100% wound contraction on day 14 in non-infected group, on day 16 in Staphylococcus aureus infected group and on day 18 in Pseudomonas aeruginosa group. CONCLUSIONS: Chloroform extract of Flabellaria paniculata proves to be a potential anti-infective and wound healing agent. Its in vitro antibacterial and in vivo wound healing activities are in good agreement with the local medicinal use of the plant for skin diseases and sores.

Antimicrobial potential of Spondias mombin, Croton zambesicus and Zygotritonia crocea.

The antimicrobial activity of Spondias mombin, Croton zambesicus and Zygotritonia crocea sourced from herbalists through an ethnobotanical survey of Egbado-South in Ogun State in Nigeria is reported. The extracts of the leaf of Spondias mombin and the stem bark of Croton zambesicus exhibited wide spectrum antibacterial effects comparable to those of ampicillin and gentamycin. The antifungal effect of extracts of Zygotritonia crocea and Croton zambesicus were comparable to those of tioconazole. There is justification for the use of these little studied medicinal plants as antiinfective agents in traditional medicine.