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Two minor ether-soluble resin glycosides, scammonins VII and VIII, were isolated from Radix Scammoniae, the roots of Convolvulus scammonia. In addition to (2S)-2-methylbutyric acid and tiglic acid, they are composed, respectively, of orizabic acid A and a new glycosidic acid named scammonic acid B, with similar macrocyclic ester structures to those of the scammonic acid A-based scammonins I-VI. Isolation of genuine scammonins III-V, which were previously obtained as peracetates, is also described.

The ether-soluble resin glycoside ('jalapin') fraction obtained from scammony roots, on alkaline hydrolysis, gave a glycosidic acid, scammonic acid A, together with isobutyric, 2S-methylbutyric and tiglic acids. In addition, two kinds of resin glycosides, named scammonin I and II, were isolated and characterized, respectively, as (11S)-hydroxyhexadecanoic acid, 11-[( O-6-deoxy-4-O-(2(E)-methyl-1-oxo-2- butenyl)-beta-D-glucopyranosyl-(1----4)-O-6-deoxy-2-O-(2-methyl-1-oxobut yl)- alpha-L-mannopyranosyl-(1----2)-O-beta-D-glucopyranosyl-(1----2)-6-deoxy -beta- D-glucopyranosyl]oxy)-, intramol. 1,3"'-ester and (11S)-hydroxyhexadecanoic acid, 11-[( O-beta-D-glucopyranosyl-(1----4)-O-6-deoxy-2-O-(2-methyl-1-oxobutyl)- alpha-L-mannopyranosyl-(1----2)-O-beta-D-glucopyranosyl-(1----2)-6-deoxy -beta-D - glucopyranosyl]oxy)-, intramol. 1,3"'-ester.

The formation and the function of the resin channels result from processes in the history of development; differences between various pine varieties must be traced to differentiation processes in the history of development. Longer flowing duration, higher reformation speed and reduced crystallization are properties which make Pinus merkusii especially suited for systematic resin production. Pinus merkusii does not react to treatment with weak acids or biologically effective stimulants, like yeast extract solution, which can be used to increase the yield of Pinus massoniana up to 30%. This means specific stimulants for Pinus merkusii still have to be found.

The results of patch tests with colophony in the standard series between 1983 and 1987 were analyzed. 5521 patients were tested in the Department of Dermatology, Hamburg, while 354 were tested in other clinics and private practices. Colophony was positive in 2.4% and 11.9%, respectively. Out of 62 patients in the 1st group and 75 in a 2nd group tested subsequently with 6 unmodified types of colophony and 12 types of modified-colophony products, 17 did not react to the unmodified material. However, most of them responded to 1 or more of the modified products. In the enlarged group (n = 75), reactions to Abitol and the maleic-modified products were the most frequently obtained. As the authors are convinced that the actual incidence of allergic reactions to modified-colophony products is underestimated, they propose to test a mixture of 3 materials: Chinese colophony (today 50% of the world market) and 2 derivatives (modified colophony), instead of the 60% mix of unmodified colophony, in the standard series.

7-oxodehydroabietic acid and 15-hydroxydehydroabietic acid were isolated as their methyl esters from Portuguese colophony of the gum rosin type and identified as contact allergens. Another oxidation product of dehydroabietic acid, 15-hydroxy-7-oxodehydroabietic acid, was synthesized and identified as a component of Portuguese gum rosin. 7-oxodehydroabietic acid was found to a be a grade III allergen according to the GPMT method. Guinea pigs induced with gum rosin showed only a low response to the isolated compounds, while patients with a known allergy to gum rosin reacted to a greater extent. The results imply that the content of oxidized dehydroabietic acids in gum rosin is too low to give a marked sensitization in the animals. However, the patients might have come in contact with the allergens in technically modified rosins. The compounds showed a pattern of cross-reactivity in the animal experiments as well as among the patch tested patients.

Contact dermatitis from lichens is now well documented but the possible influence of exposure to sunlight is less clear. Positive reactions on photopatch testing has recently been described, but whether this represented an unspecific exacerbation or a true photoallergic response was difficult to evaluate. In this study 13 different substances derived from lichens commonly found in nature were investigated with regard to their capacity to induce photo-oxidative membrane damage, as revealed by the photohemolysis technique. It was found that the earlier suggested ability to induce photosensitization could be confirmed for several of the lichen compounds investigated. It was also shown that singlet state excited oxygen may participate to some degree in some of these reactions.

One antimicrobial substance was obtained from the epicarp of the fruits of Paulownia fortunei and Paulownia tomentosa. Other parts of the fruits and leaves had no detectable antimicrobial activity. The substance was active in vitro for Staphylococcus aureus and Bacillus subtilis while it had lower activity for Saccharomyces carlsbergensis and the lowest was for Escherichia coli. The active material was extracted with organic solvents (ether, ethanol and acetone). The activity "in vitro" was demonstrated by the method of dilution in nutrient agar media. The active substance looked as a resin and was insoluble in water at neutral or acid pH. It was very soluble in strong alkaline pH solution.