Historically, natural products have been used since ancient times and in folklore for the treatment of many diseases and illnesses. Classical natural product chemistry methodologies enabled a vast array of bioactive secondary metabolites from terrestrial and marine sources to be discovered. Many of these natural products have gone on to become current drug candidates. This brief review aims to highlight historically significant bioactive marine and terrestrial natural products, their use in folklore and dereplication techniques to rapidly facilitate their discovery. Furthermore a discussion of how natural product chemistry has resulted in the identification of many drug candidates; the application of advanced hyphenated spectroscopic techniques to aid in their discovery, the future of natural product chemistry and finally adopting metabolomic profiling and dereplication approaches for the comprehensive study of natural product extracts will be discussed.

https://minerva-access.unimelb.edu.au/bitstream/handle/11343/265172/PMC3901206.pdf

A historical overview of natural products in drug discovery.

In the last three decades the discovery of metabolites with biological activities from macroalgae has increased significantly. However, despite the intense research effort by academic and corporate institutions, very few products with real potential have been identified or developed. Based on Silverplatter MEDLINE and Aquatic Biology, Aquaculture & Fisheries Resources databases, the literature was searched for natural products from marine macroalgae in the Rhodophyta, Phaeophyta and Chlorophyta with biological and pharmacological activity. Substances that currently receive most attention from pharmaceutical companies for use in drug development, or from researchers in the field of medicine-related research include: sulphated polysaccharides as antiviral substances, halogenated furanones from Delisea pulchra as antifouling compounds, and kahalalide F from a species of Bryopsis as a possible treatment of lung cancer, tumours and AIDS. Other substances such as macroalgal lectins, fucoidans, kainoids and aplysiatoxins are routinely used in biomedical research and a multitude of other substances have known biological activities. The potential pharmaceutical, medicinal and research applications of these compounds are discussed.

Medicinal and pharmaceutical uses of seaweed natural products: A review

Eucalyptus essential oil as a natural pesticide

Biological activities of sesquiterpene lactones

Antibacterial activity of East African medicinal plants

A new compound named eucamalol and 4-isopropylbenzyl alcohol were isolated as mosquito repellents from the essential oil of Eucalyptus camaldulensis. The structure of eucamalol was elucidated to be 3-formyl-6α-isopropyl-2-cyclohexen-1β-ol by 1 H NMR analysis and confirmed by synthesis. Both compounds exhibited potent repellent activities against Aedes aegypti

New mosquito repellent from Eucalyptus camaldulensis

Occurrence of the insecticidal 16,17-didehydro-16(E)-stemofoline in Stemona collinsae.

A new natural mosquito repellent was isolated from fresh leaves of Vitex rotundifolia. Its structure was elucidated by an extensive NMR spectral analysis to be a cyclopentene dialdehyde named rotundial. This compound possessed potent repelling activity against Aedes aegypti.

Keisuke Watanabe

Papers

New mosquito repellent from Eucalyptus camaldulensis

Occurrence of the insecticidal 16,17-didehydro-16(E)-stemofoline in Stemona collinsae.

Rotundial, a new natural mosquito repellent from the leaves of Vitex rotundifolia.

A polyhalogenated insecticidal monoterpene from the red alga, Plocamium telfairiae

Sesquiterpene lactones and diterpenoids from Helianthus argophyllus