Bioactive new compounds from endangered tropical plant species
Biologists have isolated 17 secondary metabolites, including three new compounds from the precious and endangered tropical plant species Alangium longiflorum. The newly isolated compound 8-hydroxycholine showed growth inhibition at several subcellular levels against several human tumor cell lines, except for cells overexpressing drug transporters. Compound 1 caused accumulation of sub-G1 cells and had no effect on cell cycle progression, indicating that the substance is an apoptosis inducer
Natural products are well known as valuable resources for drug discovery and development. In particular, plant-derived natural products have greatly facilitated the field of cancer chemotherapy. Many anti-tumor drugs currently in clinical use, such as paclitaxel, vinca alkaloids (vinblastine and vincristine), podophyllotoxin analogues (etoposide and teniposide) and topotecan (camptothecin) ) are based on natural plants. According to a report, from 1981 to 2014, 83% of new chemical entities identified as anticancer drugs were derived from natural products.
In the late 1980s and 1990s, the National Institute of Cancer (NCI, Frederick, MD) Natural Products Division (NPB) supported the collection of ca. 80,000 plant samples from the tropical regions of the Americas, Africa, and Southeast Asia. The extracts from ca. 3,000 species showed significant anti-proliferative activity at a concentration of 20 ?g/mL, and 70% of these active species were from the rainforest or its adjacent areas. Although tropical rainforest plants are important for drug discovery, unfortunately, due to climate change, industrial and economic development, these valuable regions are declining, leading to the extinction crisis of many plant species.Rainforest plant Alangium longiflorum Merr. (Hawthorne) is threatened with extinction and is currently in the Red List of Endangered Species created by the International Union for the Conservation of Nature and Natural Resources (IUCN). The crude organic extract from the leaves of A. longiflorum showed extensive cytotoxicity and a more specific anti-proliferative effect on the growth of leukemia cell lines in the NCI-60 human tumor cell line group. A collaborative phytochemical and biological study of this extract as a source of anticancer drugs was conducted by the Kanazawa University research team and NCI's NPB.
Plants are the first source of medicine and are the main source of modern medicine to date. Surprisingly, about. 90% of higher plants have not been investigated for phytochemistry. The rainforest can provide a rich variety of plants that are expected to be valuable resources for discovering new biologically active natural products with unique phytochemical properties. We will continue to work to identify new bioactive natural products from rainforest plants through collaboration with NCI.
