Most reports on the identification of known flavonoids in new plant sources as well as those on novel flavonoids naturally deal with the two most abundant classes, the flavones and flavonols. For this chapter we have listed all references to the occurrence of flavone and flavonol aglycones which have appeared from 1975 to 1980, and also include such earlier references as were overlooked in the relevant chapters of The Flavonoids’ (1975). Emphasis is given to the natural distribution of these compounds. The data are collected in Tables 4.1 and 4.2 which cite substances, plant sources and references. Since 1974, some 50 flavones and 60 flavonols with common substitution patterns have been described as novel compounds. Many are simply new methyl ethers of known compounds. The structures are arranged throughout the Tables by number and arrangement of substituents in ring A, followed by ring B. Wherever possible, the plant organs from which the compounds have been isolated are cited. In cases where authors have extracted the ‘whole plant’ or ‘aerial parts’, it does not necessarily follow that the compound is present in all parts, since these substances are often specifically located in certain organs only. In all cases where free aglycones are encountered, especially highly methylated flavonoids, it is likely that they occur externally, or are associated with secretory structures and are correlated with the production of other lipophilic secondary compounds, mainly of terpenoid origin.

Flavones and Flavonols

Clerodendrum serratum (L.) Moon. – A review on traditional uses, phytochemistry and pharmacological activities

Acacetin, a flavone with diverse therapeutic potential in cancer, inflammation, infections and other metabolic disorders.

Cyclopeptide alkaloids from Zizyphus jujuba.

Traditional uses and pharmacological properties of Clerodendrum phytochemicals.

Apigenin, acacetin and a new flavone glycoside, characterised as the methyl ester of acacetin-7-0-glucuronide have been isolated from the flowers of Clerodendron infortunatum.

Flavonoids from the flowers of Clerodendron infortunatum.

Cyclopeptide alkaloids from Zizyphus nummularia

Fumariline, a spirobenzylisoquinoline alkaloid, was isolated from the seeds of FUMARIA INDICA. Pharmacological investigations with fumariline indicated that the alkaloid is a central nervous system depressant.

K. K. Seth

Papers

Flavonoids from the flowers of Clerodendron infortunatum.

Cyclopeptide alkaloids from Zizyphus nummularia

Pharmacological actions of fumariline isolated from Fumaria indica seeds.