Aloe vera (L.) Burm. fil. (= A. barbadensis Miller) (Liliaceae) is native to North Africa and also cultivated in Turkey. Aloes have long been used all over the world for their various medicinal properties. In the past 15 years, there have been controversial reports on the hypoglycaemic activity of Aloe species, probably due to differences in the parts of the plant used or to the model of diabetes chosen. In this study, separate experiments on three main groups of rats, namely, non-diabetic (ND), type I (IDDM) and type II (NIDDM) diabetic rats were carried out. A. vera leaf pulp and gel extracts were ineffective on lowering the blood sugar level of ND rats. A. vera leaf pulp extract showed hypoglycaemic activity on IDDM and NIDDM rats, the effectiveness being enhanced for type II diabetes in comparison with glibenclamide. On the contrary, A. vera leaf gel extract showed hyperglycaemic activity on NIDDM rats. It may therefore be concluded that the pulps of Aloe vera leaves devoid of the gel could be useful in the treatment of non-insulin dependent diabetes mellitus

Abstract:The aim of our study was to evaluate the effect of in vitro anticancer and cytotoxic activity of the methanolic extracts of 14 medicinal plants, 8 of which are endemic species in Anatolia, against the human HeLa cervical cancer cell line and to compare to the normal African green monkey kidney epithelial cell line (Vero) using the MTT colorimetric assay. Values for cytotoxicity measured by MTT assay were expressed as the concentration that causes 50% decrease in cell viability (IC50, μg/mL). The degree of selectivity of the compounds can be expressed by its selectivity index (SI) value. High SI value (>2) of a compound gives the selective toxicity against cancer cells (SI = IC50 normal cell/IC50 cancer cell). Dose-dependent studies revealed IC50 of 293 mg/mL and >1000 mg/mL for Cotinus coggygria Scop., IC50 of 265 μg/mL and >1000 mg/mL for Rosa damascena Miller, IC50 of 2 μg/mL and 454 mg/mL for Colchicum sanguicolle K.M. Perss, IC50 of 427 μg/mL and >1000 μg/mL for Centaurea antiochia Boiss. var. praealta (Boiss & Bal) Wagenitz on the HeLa cells and the Vero cells, respectively. Four plants showed significant SI values which were 227 for Colchicum sanguicolle K.M. Perss (endemic species), >3.8 for Rosa damascena Miller, >3.4 for Cotinus coggygria Scop. and >2.3 for Centaurea antiochia Boiss. var. praealta (Boiss & Bal) Wagenitz (endemic species). According to our study, 4 methanolic extracts of 14 tested plants exhibit greater activity on the HeLa cell line and little activity on the Vero cell line, meaning that these plants can be evaluated for potential promising anticancer activity.

One of the food intoxications encountered in Turkey is the case caused by toxic honey made by bees from Rhododendron species. R. luteum and R. ponticum are the two species which grow in the north regions of Turkey. Grayanotoxins, mainly Grayanotoxin I (Andromedotoxin) occurring only in Ericaceae plants, are the compounds responsible for poisoning. In this investigation, the diagnosis and treatment of 11 cases of poisoning admitted to Kartal Occupational Diseases Hospital between 1983 and 1988 are presented. The results of the light microscopic and chemical analysis of toxic honey samples are compared with those of the ordinary honey samples and the extract of Rhododendron leaves.

The aim of our study was to evaluate in vitro antioxidant potential of methanolic extracts (ME) of 14 medicinal plants, 8 of which are endemic species of Anatolia. Scavenging activity was tested by 1,1-diphenyl-2-picrylhydrazyl (DPPH) method and the inhibitory effect on lipid peroxidation was examined by the ferric thiocyanate (FTC) and thiobarbituric acid (TBA) methods. The obtained results showed significant differences in the antioxidant potential amongst the tested methanolic plant extracts. Among the plant samples, Crataegus microphylla C. Koch, Salvia hypargeia Fisch. & Mey., Cotinus coggygria Scop., Origanum sipyleum L. and Rosa damascena Miller exhibited the highest DPPH scavenging activity. Five extracts (Centaurea nerimaniaeŞ. K€ ult€ ur, C. coggygria, Scorzonera tomentosa L., R. damascena and Colchicum sanguicolle K.M. Perss) showed strong antioxidant activity in the FTC and TBA tests, with per cent inhibition ranges of 72%À84% and 84%À92%, respectively. The ME of C. coggygria and R. damascena exhibited potent antioxidant activity by the DPPH, FTC and TBA methods.

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