As a traditional medicine, many Ayurveda products have not been tested in rigorous scientific studies and clinical trials. A systematic review of Ayurveda treatments for rheumatoid arthritis concluded that there was insufficient evidence, as most of the trials were not done properly, and the one high-quality trial showed no benefits. A review of Ayurveda and cardiovascular disease concluded that while the herbal evidence is not yet convincing, the spices are appropriate, some herbs are promising complementary treatment. Some ayurvedic products, mainly herbs used for phytotherapy, have been tested with promising results. Turmeric and its derivative curcumin appears to have beneficial properties. Tinspora cordifolia has been tested. Among the medhya rasayanas (intellect rejuvenation), two varieties of Salvia have been tested in small trials; one trial provided evidence that Salvia lavandulifolia (Spanish sage) may improve word recall in young adults,and another provided evidence that Salvia officinalis (Common sage) may improve symptoms in Alzheimer's patients. In some cases Ayurvedic medicine may provide clues to therapeutic compound