Herbal Anti Cancer Medicine : The Vinca Alkaloids Isolated From The Madagascar Periwinkle Plant Essay

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The first herbal anti-cancer medicine was the vinca alkaloids isolated from the Madagascar periwinkle plant, Catharanthus roseus. Extracts from this plant was found to have therapeutic anti-tumour activity and clinically began being used as Vinblastine and Vincristine in 1960. [2] The mechanism of Vinca Alkaloids is the inhibition of microtubules. The drug prevents the alignment of daughter chromosomes by depolymerizing the tubulin molecules inhibiting the formation of spindle fibres ultimately causing mitosis arrest and killing dividing cells. [3]
This class of drug is at danger due to resistance mechanisms via the over expression of multi-drug associated p-glycoprotein which acts as an efflux pump to remove the drug out of the cell. [5] Resistance has led to the development of second generation Vinca Alkoids – Vinorelbine and Vinflunine. these drugs disrupt microtubule formation by alternate methods compared to the older generation hence prolonging multi-drug resistance and anti-angiogenesis which prevents new blood vessels forming to the tumour. From clinical studies Vinorelbine is approved for treatment of Non-small cell lung cancer, (Gregory et al. 2000) over 15 trials with Vinorelbine as monotherapy has produced an overall response rate of 23.6% increasing patient’s survival. A phase 3 trial from an Italian study in 1999 (The Elderly Lung Cancer, Vinorelbine) found that ‘monotherapy vinorelbine seemed reasonable in the elderly whom polychemotherapy is not possible’.
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