a b s t r a c tAim: To validate plant species for hypoglycaemic activity. Materials and methods: Four plants were investigated for hypoglycaemic activity by evaluating inhibiting effects on carbohydrate-hydrolising enzymes: ␣-glucosidase and ␣-amylase. Acetone plant extracts were screened against C2C12 myocytes, 3T3-L1 preadipocytes and Chang liver cells by measuring glucose uptake. Cytotoxicity was done in preadipocytes and hepatocytes. Results: Extract of Euclea undulata rootbark exhibited highest activity, displaying a glucose uptake of 162.2% by Chang liver cells at 50 g/ml. An inhibition concentration of 50% for Euclea undulata was found to be 49.95 g/ml for ␣-glucosidase and 2.8 g/ml for ␣-amylase. No cytotoxicity was recorded for Euclea undulata, while Schkuhria pinnata and Elaeodendron transvaalense exhibited cytotoxicity at 12.5 g/ml. ␣-Glucosidase and ␣-amylase assays showed inhibitory activity on enzymes for three plant extracts. Conclusion: Euclea undulata, Schkuhria pinnata and Elaeodendron transvaalense showed in vitro hypoglycaemic activity. Schkuhria pinnata and Elaeodendron transvaalense indicated cytotoxicity on 3T3-L1 preadipocytes and Chang liver cells. Euclea undulata, Pteronia divaricata and Elaeodendron transvaalense inhibited ␣-glucosidase and ␣-amylase enzymes. Ethnopharmacological relevance: Screening of plant extracts scientifically validated traditional use of Euclea undulata for treatment of diabetes. Cytotoxicity results revealed that acetone extracts of Schkuhria pinnata and Elaeodendron transvaalense are toxic and raise concern for chronic use.

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Aim of the study: Investigate the hypoglycaemic activity of the four isolated compounds from a crude acetone extract of the root bark of Euclea undulata var. myrtina, which is used by traditional healers in the Venda area, Limpopo Province in the treatment of diabetes. Material and Methods:The hypoglycaemic activity of the four compounds isolated from E. undulata was determined by in vitro screening of glucose utilization by C2C12 myocytes at a concentration of 25 µg/ml or 50 µg/ml. The inhibition of α-glucosidase was also tested at concentrations ranging from 0.02 to 200.00 µg/ml.Results: Assay-guided isolation of the crude acetone extract of the root bark of E. undulata var. myrtina. afforded a new triterpene, α-amyrin-3O-ß-(5-hydroxy) ferulic a c i d ( 1 ) , in addition to three known compounds; betulin (2), lupeol (3) and epicatechin (4). The in vitro results on C2C12 myocytes suggest that compound 4 may have some effect to lowers blood glucose levels, whereas compound 1 has the ability to inhibit α-glucosidase at a concentration of 200.0 µg/ml with an IC 50 value of 4.79 that correlates with that of the positive control acarbose IC 50 value 4.75. Conclusion:The results suggest that 4 may have some ability to lower blood glucose levels, whereas 1 has the ability to inhibit α-glucosidase.Ethnopharmacological relevance: These findings corroborate the ethnomedicinal use of E. undulata by traditional healers for the treatment of diabetes as two substances was isolated from the acetone plant extract that exhibit hypoglycaemic activity.

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The study of the vegetation of the Ruimsig Entomological Reserve, Gauteng, South Africa revealed four plant communities one of which could be subdivided into two subcommunities and variants. The extensive climax stage of the vegetation represented by the Themeda triandra - Trachypogon spicatus grassland was found to be too dense and tall to support the butterfly Aloeides dentatis dentatis and the host ant Lepisiota capensis (Mayr). A degraded phase caused by succession in an area where pipes have been laid was found to be ideal habitat for both ant and butterfly. This vegetation also contained adequate numbers of the food plant Hermannia depressa. A serai community with tall- growing Hyparrhenia hirta was also found to be an unsuitable habitat for the butterfly. The identification of the preferred ideal habitat for the host ant and butterfly resulted in the compilation of a conservation management strategy that ensured the survival of the rare and endangered butterfly.

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