D. Martín-Herrera

Antimicrobial activity of extracts from plants endemic to the Canary Islands

The antibacterial and antifungal activities of several extracts and fractions from four endemic Canary plants, Ceropegia fusca Bolle (Asclepiadaceae), Hypericum reflexum L. f. (Hypericaceae or Guttiferae), Maytenus canariensis (loes) Künkel & Sunding (Celastraceae) and Plocama pendula Ait. (Rubiaceae), were determined.

Diuretic activity of some Withania aristata Ait. fractions

We previously reported on the significant dose-dependent diuretic effects produced in laboratory rats by hot water infusions and methanol extracts of Withania aristata Ait., where notable increases were observed in the excretion of water and sodium, with an interesting potassium-saving effect. The present study gives the results of the diuretic effects in rats of the hexane, dichloromethane, ethyl acetate, butanol and methanol-water fractions of the previously studied methanol extract. Water excretion rate, pH, density, conductivity and content of Na(+), K(+) and Cl(-) were measured in the urine of the rats when subjected to hypersaline conditions. Of the above fractions, the methanol:water extract (100mg/kg) showed the most interesting diuretic activity (25%; p<0.01), which suggested that increase in the polarity of the extracting solvent led to an increase in the concentration of the polar compounds responsible for the diuretic effect. These data, together with previous results on the aqueous and methanol extracts, reaffirm assertions made regarding the effectiveness of the extracts of this plant against urinary pathologies in the Canary Islands folk medicine.

Withanolides from Whitania aristata and their diuretic activity.

AIM OF THE STUDY Withania aristata is an endemic plant used traditionally in Canary Islands as a diuretic. In this paper, we report on this pharmacological activity in several extracts of the dry vegetal material collected and the identification and diuretic activity of two withanolides, one of them previously not reported, isolated from the most active fraction. MATERIAL AND METHODS Four Whitania aristata extracts at 100 mg/kg were orally administered to laboratory animals to evaluate their diuretic activity. From the most active fraction, two withanolides were isolated. Both and a mixture of them at 5 and 10 mg/kg were analyzed too as diuretics. Water excretion rate and content of Na(+) and K(+) electrolytes were measured in the urine of saline-loaded animals. RESULTS Whitania aristata water fraction, the two withanolides and the mixture of these compounds displayed high diuretic activity, with a significant excretion of sodium and potassium ions in laboratory animals. CONCLUSIONS This research supports the ethno-medicinal use of Whitania aristata as diuretic. This activity seems to be associated to the presence of a new type of natural diuretic agents, such as withaferin A and witharistatin.

Essential oils and antimicrobial activity of two varieties of Cedronella canariensis (L.) W. et B.

The qualitative and quantitative determination of the essential oils of the aerial part of two varieties of Cedronella canariensis (L.) W. et B., namely, C. canariensis var. canariensis and C. canariensis var. anisata have been performed, together with the study of the antimicrobial activity of both oils. The noteworthy inhibition exhibited against Bordetella bronchiseptica and Cryptococcus albidus may justify the popular use of the these plants in the treatment of certain diseases of the respiratory tract.

Study of the Hypoglycaemic, Diuretic and Cardiovascular Activity of Cedronella canariensis var. canariensis (L.) W. & B.

The hypoglycaemic, diuretic and cardiovascular activities of an infusion and CHCl3 extract of the aerial part of Cedronella canariensis (L.) Webb & Berth are presented. It was observed that the CHCl3 extract had a significant hypoglycaemic and diuretic effect. At the cardiovascular level, the infusion and CHCl3 extract exercised a marked hypotensor effect in vivo and a brachycardiac activity in the isolated atria of the rat.

Diuretic Activity of Extracts from Astydamia latifolia, Forsskaolea angustifolia and Ceterach aureum in Rats

We have confirmed the diuretic properties attributed to three endemic species from the Canary Islands. The plants chosen were Astydamia latifolia (L.f.), Forsskaolea angustifolia (Retz) and Ceterach aureum (Cav.) Buch. and Paronychia canariensis. The results confirm a diuretic activity probably due to high content of potassium salts