Friday, May 7, 2010

The Lesser Periwinkle

A guest post by Ken.

During a short walk in Knaresborough, in North Yorkshire, I discovered a wonderful looking plant. It was the Lesser Periwinkle (Vinca minor). This plant is a member of the periwinkle family Apocynaceae, which are creeping woody shrubs with opposite, evergreen, oval untoothed leaves and have corollas with 5 spreading lobes, twisted in bud. The other member of the family is the Greater Periwinkle (V. major) and although very similar to V. minor, the calyx-teeth on the Greater Periwinkle are hairy and the leaves are oval rather than lanceolate. (Rose, Francis et. al. The Wild Flower Key; Revised edition, 2006, p.352).

The Lesser Periwinkle - Vinca minor

The alkaloid vincamine from this Lesser Periwinkle is used in the production of the synthetic compound vinpocetine. This is a potent neuroprotective agent. It is used in neurological practice, particularly in cerebrovascular diseases such as ischemic stroke. The drugs main pharmacological and physiological actions are not fully understood. Recent studies have shown that Vinpocetine contributes to a regional redistribution of cerebral blood flow in such a way that relatively more blood reaches the brain structures which show a high uptake of radiolabelled vinpocetine. The chemical can also regionally modify the utilisation of glucose in the brain and this effect is more pronounced in the affected hemisphere. These effects of vinpocetine suggest that, through direct CNS effects, the drug can usefully contribute to the restoration of physiological conditions in stroke patients. (Geza Szilagyi, Zoltan Nagy, Laszlo Balkay, Istvan Boros, Miklos Emri, Szabolcs Lehel, Terez Marian, Tamas Molnar, Szabolcs Szakall, Lajos Tron, Daniel Bereczki, Laszlo Csiba, Istvan Fekete, Levente Kerenyi, Laszlo Galuska, Jozsef Varga, Peter Bonoczk, Adam Vas, Balazs Gulyas, Effects of vinpocetine on the redistribution of cerebral blood flow and glucose metabolism in chronic ischemic stroke patients: a PET study, Journal of the Neurological Sciences, Volumes 229-230, Vascular Dementia, 15 March 2005, Pages 275-284).

One did a spot of rowing that day too. Icelandic volcanic ash clouds prevented me from flying. Still, at least I got to see another beautiful plant.

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