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Five new chromone C-glycosides have been obtained from the leaves of Baeckea frutescens. They are: 6-β-C-glucopyranosyl-5,7- dihydroxy-2-isopropylchromone, 8-β-C-glucopyranosyl-5,7-dihydroxy-2-isopropylchromone, 6-β-C-glucopyranosyl-5,7-dihydroxy- 2-methylchromone, 6-β-C-(2′-galloylglucopyranosyl)-5,7-dihydroxy-2-isopropylchromone and 8-β-C-(2′-galloylglucopyranosyl)-5,7-dihydroxy-2-isopropylchromone.

Six triterpenoids were isolated from the callus tissues of Paeonia japonica, P. lactiflora and P. suffruticosa. Four of the compounds are new from a natural source: 11α,12α-epoxy-3β,23-dihydroxyolean-28,13β-olide, 3β-hydroxy-11-oxo-olean-12-en-28-oic acid, 3β-hydroxy-oleana-11,13(18)-dien-28-oic acid and 3β,23-dihydroxy-oleana-11,13(18)-dien-28-oic acid. The postulated biosynthetic sequence of these compounds is discussed and the triterpenoids produced from the three callus tissues have been compared from a chemotaxonomical standpoint.

From the frond of Oreopteris quelpaertensis , a novel chalcone-like product has been isolated as a mixture of keto—enol tautomeric isomers, along with its dimeric form, and their structures were determined by extensive 2D NMR spectroscopy or X-ray diffraction. Isoquercitrin was also obtained from this fern.

A new anthraquinone glycoside, physcion 8-O-β-rutinoside, has been isolated from the bark of Rhamnus libanoticus together with emodin, its 6-O-α-l-rhamnoside and 8-O-β-d-glucoside, and kaempferol.

A new acetophenone glycoside and two new naphthalide glycosides have been isolated from the bark of Turkish Rhamnus libanoticus together with 7-hydroxy-5-methoxyphthalide 7- O -β-D-glucoside. The structures of the new compounds were elucidated by spectroscopic methods as 2,6-dihydroxy-4-methoxyacetophenone 2- O -β- rutinoside, 8,9-dihydroxy-6-methoxynaphthalide 8- O -β-rutinoside, 8,9-dihydroxy-6-methoxynaphthalide 8- O -/3b-D glucoside, respectively.

A chemical assay of ptaquiloside, the major carcinogen of Pteridium aquilinum , based on two-dimensional TLC-densitometry, was devised. The contents of ptaquiloside and related compounds in the fern collected at four places at different seasons were compared and the epidemiological implications of the results are discussed. The behaviour of ptaquiloside on treatment with acid, alkali, light and heat was examined and the instability of the compound, especially under alkaline conditions, was confirmed. The distribution of ptaquiloside and ptaquiloside-like substances in the Pteridaceae was examined by the use of the chemical assay and the modified Ames' test, and widespread occurrence of such compounds was revealed.

The investigation of four pteridaceous ferns afforded, in addition to known pterosins, six new pterosins and three new pterosides. The structures are elucidated mainly by spectroscopic methods.