Extractives from the Meliaceae and Annonaceae.

Abstract

Members of the Annonaceae and Meliaceae, two plant families which are distributed throughout the world, have been studied during the course of this work. The research is an account of the compounds isolated from six members of the Meliaceae (Australian, Indian and South African) and one from the Annonaceae (South African). These families have attracted special attention of scientists world-wide because of the compounds these plants produce and their medicinal applications. Extracts from these species are known to be widely used in traditional medicine and previous studies have demonstrated their anticancer, anti-microbial and other pharmacological activities. Limonoids and protolimonoids were isolated from the Indian Meliaceae specIes, Aphanamixis polystacha and from the South African Meliaceae species Turraea obtusifolia. Extractives from the seeds of Aphanamixis polystacha yielded seven limonoids (2-A to 2-G) from the hexane extract, while the methanol extract only yielded sucrose (2-H). Three of the limonoids (2-B, 2-E and 2-F) were novel and the stereochemistry of polystachin, compound (2-A), was revised. Extractives from Turraea obtusifolia yielded two triterpenoids (3-A and 3-B) and a limonoid (3-C) from the hexane extract of the seed. Several triterpenoids and a benzofuran compound were isolated from the Australian Meliaceae species, Dysoxylum pettigrewianum, Dysoxylum muelleri and Aglaia sapindina. Extractives from Dysoxylum pettigrewianum, yielded three triterpenoids (4-A to 4-C) from the hexane extract of the bark. Two of these triterpenoids (4-Band 4-C) were novel. Extractives from Dysoxylum muelleri yielded two triterpenoids (4-D and 4E) from the methylene chloride extract of the wood. Extractives from Aglaia sapindina yielded a benzofuran compound (4-F) from the hexane extract of the wood. This resulted in the revision of the structure of ferrugin (4-56). A flavonoid (5-A) was isolated from the aqueous extract of the seed of the South African Meliaceae Trichilia dregeana. A polyoxygenated cyclohexane epoxide (6-A) was isolated from the root and leaves of the Annonaceae species, Monanthotaxis caffia. The research undertaken involved the collection, extraction, isolation, purification and structural elucidation of these compounds by infrared, mass and nuclear magnetic resonance spectroscopic techniques.