Clemence Zimudzi

Diversity, Population Structure, and Above Ground Biomass in Woody Species on Ngomakurira Mountain, Domboshawa, Zimbabwe

The diversity, structure, species composition, and above ground biomass of woody plants on Ngomakurira mountain in Zimbabwe were studied. A systematic random sampling approach was adopted to establish 52 sampling plots measuring 10 × 10 m across 3 study strata in the 1266 ha study area. Woody species occurring in each plot were identified and the circumferences of trees with diameters >8.0 cm at 1.3 m height were measured. A total of 91 species belonging to 74 genera and 39 families were identified in the sample plots. A Shannon-Wiener index mean value of 3.12 was obtained indicating high species diversity on the mountain. The DBH size class distribution showed inverse J distribution patterns across the three study strata, but with only 3 individual plants with DBH > 30 cm. Mean basal area was 15.21 m2 ha−1 with U. kirkiana and J. globiflora contributing approximately 30% of the basal area. The estimated above ground biomass ranged from 34.5 to 65.1 t ha−1. Kruskal-Wallis-H test showed no significant differences in species richness, stem density, basal area, above ground biomass, and evenness, across the study strata ( ). Ngomakurira woodland has potential to regenerate due to the presence of many stems in the small diameter size classes.

Phytochemical, Anti-nutrients and Toxicity Evaluation of Cleome gynandra and Solanum nigrum: Common Indigenous Vegetables in Zimbabwe

Aim: This study assesses the phytochemical profiles, toxicity and anti-nutrient properties of two indigenous vegetables, Cleome gynandra and Solanum nigrum. Methodology: Aerial parts of S. nigrum and C. gynandra collected from wild populations were extracted in water and methanol solvents using the cold maceration procedure. Chemical tests to identify different phytochemicals and antinutrients were carried out using specified reagents. Toxicity of the plant extracts was tested using the Brine Shrimp (Artemia salina) lethality bioassay procedure. Results: Phytochemical tests indicated presence of alkaloids, steroids, flavonoids, cardiac glycosides, saponins, phenols and tannins in both S. nigrum and C. gynandra. Anthraquinones were only found in C. gynandra, whereas terpenoids and coumarin glycosides were found only in Original Research Article Sango et al.; BBJ, 13(3): 1-11, 2016; Article no.BBJ.25164 2 S. nigrum. The anti-nutrient levels in the vegetables were high; tannins (3.580 and 1.820 mg/ 100 g), oxalates (21.560 and 24.97±0.156 g/100 g), saponins (71 and 42%), alkaloids (15.160 and 3.44%) and phytates (0.099±0.046 and 0.250±0.013%) in S. nigrum and C. gynandra respectively. The Brine Shrimp LC50 values obtained were 0.67 and 1.84 mg/ml for methanol and water extracts of S. nigrum and 1.09 and 4.9 mg/ml for C. gynandra, respectively. Conclusion: The vegetables, C. gynandra and S. nigrum are rich sources of diverse phytochemicals. However, some phytochemicals are present in high levels and might act as anti nutritional factors interfering with absorption of food. C. gynandra is safe for consumption but S. nigrum contains some toxic phytochemicals and should not be taken regularly.

Phytochemical screening, cytotoxicity and anti-inflammatory activities of the Zimbabwean endemic plant Phyllanthus serpentinicola Radcl.-Sm. (Phyllanthaceae)

Article history: Received on: 10/10/2012 Accepted on: 21/10/2012 Available online: 28/10/2012 Stem methanolic extract of Phyllanthus serpentinicola was screened for phytochemicals, and tested for cytotoxicity and anti-inflammatory activities. Tests indicated presence of alkaloids, tannins, terpenoids, reducing sugars and flavonoids. Saponins, anthraquinones, and cardiac glycosides were absent. Cytotoxic effects of the plant were assessed through Brine shrimp lethality (BSL) bioassay. An LC50 value of 1.3 µg/ml was found, thus indicating that the stem extract was strongly cytotoxic. Anti-inflammatory activity was assessed by the egg albumen induced hind paw oedema test on Swiss albino mice. The extract significantly (p<0.05) reduced the oedema, thus indicating that P. serpentinicola has anti-inflammatory properties.