Cardiac glycosides (CGs) are a class of naturally occurring steroid-like compounds, and members of this class have been in clinical use for more than 1500 years. They have been used in folk medicine as arrow poisons, abortifacients, heart tonics, emetics, and diuretics as well as in other applications. The major use of CGs today is based on their ability to inhibit the membrane-bound Na+/K+-ATPase enzyme, and they are regarded as an effective treatment for congestive heart failure (CHF), cardiac arrhythmia and atrial fibrillation. Furthermore, increasing evidence has indicated the potential cytotoxic effects of CGs against various types of cancer. In this review, we highlight some of the structural features of this class of natural products that are crucial for their efficacy, some methods of isolating these compounds from natural resources, and the structural elucidation tools that have been used. We also describe their physicochemical properties and several modern biotechnological approaches for preparing CGs that do not require plant sources.
Objective: Despite the availability of modern anti-emetics, chemotherapy-induced nausea and vomiting (CINV) symptoms remain distressing to a high number of cancer patients. This study intended to (1) describe the incidence of CINV and antiemetic usage; (2) assess the health-related quality of life (HRQoL) and correlate its components with Global Health Status; (3) evaluate HRQoL status in relation to CINV among breast cancer patients receiving chemotherapy. Methods: A cross sectional study was conducted in two government hospitals located in the East Coast of Peninsular Malaysia (Terengganu, Kelantan). The Morrow Assessment of Nausea and Emesis Follow-up (MANE-FU) and European Organization for Research and Treatment of Cancer Quality of Life Questionnaire (EORTC QLQ-C30) were administered. Descriptive statistics and non-parametric tests were employed (SPSS 16). Results: Respondents included 41 female patients (age = 49 ± 9.6 years; Malay = 92.7%; no family history of breast cancer = 68.3% and on moderately emetogenic chemotherapy = 97.6%). Majority of patients experienced nausea during or after chemotherapy (90.2%) and rated it as ‘severe’. Most patients had taken anti-emetic
(87.8%) and considered it ‘somewhat useful’. The median score for Global Health Status was 50 (IqR= 16.7). Emotional Functioning, Fatigue and Pain correlated fairly with HRQoL (rs= +0.435; -0.417; -0.387 respectively). Patients with ‘a lot’ and ‘moderate’ nausea displayed significantly more fatigue compared to those with little nausea (p=0.029). Those who experienced vomiting reported worse HRQoL profile compared to those who did not (p=0.011). Conclusion: These findings generally ascertained that CINV remains poorly controlled and significantly interferes with HRQoL, providing rooms for improvements in therapeutic intervention.