RESUMO
Dendrobium nobile (Lindl.) have long been used as herbal tea and a traditional herbal medicine to treat Alzheimer's disease (AD). In the current study, nineteen compounds (1-19), including two new vitamin E homologues (1-2), one new sesquiterpene (6), and two new dendrobines (7, 8), were isolated and identified from stems of Dendrobium nobile. Their structures were elucidated on the basis of NMR, 13C NMR calculation, and DP4+ probability analyses. The absolute configurations of new compounds were determined by electronic circular dichroism (ECD) data analysis. Antioxidant, anti-inflammatory, and cytotoxic activities of isolated compounds were evaluated. Among them, compound 2 demonstrated significant antioxidant activity compared with ascorbic acid (VC), while compounds 2 and 4 also exhibited an equal effect to positive control cisplatin. This study on the biological activity of the new vitamin E homologues from Dendrobium nobile may indicate its potential application in the pharmaceutical and food industries.