Biological activities of plant extracts from Ficus elastica and Selaginella vogelli: an antimalarial, antitrypanosomal and cytotoxity evaluation

The cytotoxic, antiplasmodial, and antitrypanosomal activities of two medicinal plants traditionally used in Cameroon were evaluated. Wood of Ficus elastica Roxb. ex Hornem. aerial roots (Moraceae) and Selaginella vogelii Spring (Selaginellaceae) leaves were collected from two different sites in Cameroon. In vitro cell-growth inhibition activities were assessed on methanol extract of plant materials against Plasmodium falciparum strain 3D7 and Trypanosoma brucei brucei, as well as against HeLa human cervical carcinoma cells. Criteria for activity were an IC50 value 10 μg/mL. The extract of S. vogelii did not significantly reduce the viability of P. falciparum at a concentration of 25 μg/mL but dramatically affected the trypanosome growth with an IC50 of 2.4 μg/mL. In contrast, at the same concentration, the extract of F. elastica exhibited plasmodiacidal activity (IC50 value of 9.5 μg/mL) and trypanocidal (IC50 value of 0.9 μg/mL) activity. Both extracts presented low cytotoxic effects on HeLa cancer cell line. These results indicate that the selected medicinal plants could be further investigated for identifying compounds that may be responsible for the observed activities and that may represent new leads in parasitical drug discovery

EFFECT OF ASHWAGANDHA ON PHARMACOKINETIC AND PHARMACODYNAMIC PARAMETERS OF GLIMEPIRIDE IN STREPTOZOTOCIN-INDUCED DIABETIC RATS

 Objective: The present investigation is aimed to determine the effect of ashwagandha (AG) on pharmacokinetic (PK) and pharmacodynamic (PD) parameters of glimepiride (GP) in diabetic rats. Simultaneously, the effect was also studied in normal rats.Methods: Diabetes in rats was induced by streptozotocin. The PK parameters are calculated in normal and diabetic rats. PD studies were performed in diabetic rats only.Results: From the PK results, 2.26-folds of improvement in the oral bioavailability of GP in normal rats were observed when treated with GP in a combination of AG and which is statistically significant (p<0.001). In case of diabetic rats, the oral bioavailability (3.42-folds) of GP was significantly increased when coadministered with AG and was higher (about 33.5%) than the normal rats. Further, the rate of clearance and also the volume of distribution significantly changed in diabetic rats. The blood glucose levels were significantly reduced in GP and AG treated (6.15% reduction) compared to GP alone (5.45% reduction) treated diabetic rats during a period of 24 h were noticed from PD studies. The maximum reduction was observed at 6 h (55.46%) when compared with standard GP treatment (46.06%) in case of GP and AG combination treatment.Conclusion: Therefore, the results suggestive that, the AG might be advantageous as an adjuvant to GP in an appropriate quantity, and also the dose of GP may need to be adjusted to avoid any complications

Studies on synthesis of hypericins by undifferentiated cultures of Hypericum perforatum l.

The high demand for the therapeutically valuable natural hypericins has necessitated to look into alternative sources such as biotechnological methods for their production. Hypocotyl portions of Hypericum perforatum L. seedlings were cultured on Murashighe and Skoog (MS), and Gamborg’s B5 (B5) media supplemented with different concentrations of auxins [2,4-dichlorophenoxy acetic acid (2,4-D) or α-naphthalene acetic acid (NAA)] and cytokinins [kinetin (KN) or benzyl adenine (BA)] for the establishment of callus cultures. The frequency of callus formation was high in MS media but only two callus lines cultured under a photoperiod of 16 h in the presence of phytohormone combination NAA (1 mg/l) + KN (0.25 mg/l) and NAA (0.25 mg/l) + KN (0.025 mg/l) produced pseudohypericin and hypericin in trace amounts. The objective was to study the accumulation of hypericins by in vitro cultures and to improve or induce production by means of elicitation and precursor feeding. However, initiation of cell suspensions from such calli led to a loss of biosynthetic capacity, which could not be restored by the addition of either elicitors (copper sulphate and chitosan) or precursors (sodium acetate and emodin). The inability of cell suspensions to produce hypericins may reflect the absence of the desired biosynthetic pathways due to lack of cellular differentiation suggesting that organ cultures are appropriate culture systems for their production. Elicitation has been found to improve accumulation of hypericins in cell cultures but no reports exist regarding precursor feeding. We tested unreported elicitors and precurors but these treatments did not induce synthesis. One of the callus lines which developed 3-5 shoots accumulated hypericns confirming the results reported previously.Keywords: hypericins, Hypericum perforatum, callus cultures, elicitors, precursor

Antioxidant Activities of Three Rubus Species Growing in Ethiopia

In Ethiopian traditional medical practices some species of the genus Rubus (Rosaceae) are used for the treatment of diabetes mellitus, one of the disease conditions in which free radicals and oxidative stress have been implicated. In the present study extracts prepared from three members of the genus, namely Rubus apetalus Poir, R. niveus Thunb and R. steudneri Schweinf were investigated for their in vitro radical scavenging activities using 2,2-diphenyl-1-picrylhydrazyl (DPPH) and deoxyribose degradation assays. The 80% methanol extract, and acetone and methanol soxhlet fractions of the three plants tested showed antioxidant activity in a concentration-dependent manner. The 80% methanolic extract of R. steudneri showed the strongest activity in the DPPH radical scavenging assay (IC50 = 6.5 mg/ml). In the deoxyribose degradation assay the 80% methanol, acetone and methanol extracts of R. niveus displayed potent activity with IC50 values of 0.64, 0.6 and 0.61 μg/ml, respectively. Ascorbic acid (vitamin C) was used as a positive control in the DPPH assay (IC50 = 4.5 μg/ml) and butylhydroxytoluene, in the deoxyribose degradation assay (IC50 = 4.76 μg/ml). The results of the present study suggest that the antioxidant activity of the studied plants may contribute to their purported uses as antidiabetic agents. The work further indicated that the antioxidant active principles of the plants reside in the polar fraction of the extracts. Keywords: Rubus spp., Rosaceae, radical scavenging activity, DPPH assay, deoxyribose degradation assayEthiopian Pharmaceutical Journal Vol. 25 (2) 2007: pp. 103-11

In Vitro Radical Scavenging Activity of the Leaf and Bark Extracts of Senna singueana (Del). Lock

The leaves and bark of Senna singueana (Del). Lock (family: Fabaceae) are traditionally used in some parts of Ethiopia, for the treatment of a form of skin cancer locally called ‘Minshiro Nekersa\'. Total extracts and solvent fractions obtained from the leaves and bark; and fractions obtained from solid-phase extraction and TLC of the leaf extract were prepared and tested for their radical scavenging activity using DPPH (1,1- diphenyl-2-picrylhydrazyl) and deoxyribose degradation inhibition assays. The results revealed that all the samples tested possess strong DPPH radical scavenging activity and moderate deoxyribose degradation inhibitory effect. The IC50 values of the total extracts and solvent fractions ranged from 6.16 to 200.10 μg/ml in DPPH assay and 262.77 μg/ml to 1457.63 μg/ml in deoxyribose degradation inhibition assay. The TLC separated bands showed IC50 values ranging from 8.89 to 53.83 μg/ml, and 72.17 to 849.18 μg/ml, respectively, in the two assays. The positive control standard compounds ascorbic acid (for the DPPH assay) and butylhydroxytoluene (for the deoxyribose degradation inhibition assay) showed IC50 values of 4.46 and 4.76 μg/ml, respectively. As free radicals are known to be involved in carcinogenesis, radical scavengers can short-cut free radical mediated critical steps that lead into carcinogenesis. It was thus proposed that the observed radical scavenging activity of S. singueana may contribute partly to the possible scientific basis for the traditional anticancer use of the plant. Keywords: Senna singueana, Fabaceae, radical scavenging activity, DPPH assay, deoxyribose degradation inhibition assayEthiopian Pharmaceutical Journal Vol. 25 (2) 2007: pp. 77-8