A new antibacterial clerodane diterpenoid from the resinous exudate of Haplopappus uncinatus.

The antibacterial activity of Haplopappus uncinatus is attributed to a new clerodane diterpenoid, 18-acetoxy-cis-cleroda-3-en-15-oic acid (10 betaH, 16 xi 19 beta, 17beta, 20 alpha form) (1), isolated as a major component from the resinous exudates of its twigs and leaves, together with the inactive 3,5-dihydroxy-6,7,3',4'-tetramethoxyflavone, n-alkanes and a few sesquiterpenoids.

Chemical composition of carrageenan blends determined by IR spectroscopy combined with a PLS multivariate calibration method.

The content of kappa, iota and lambda carrageenan in mixtures was determined by application of FT-IR spectroscopy combined with partial least-squares multivariate regression (PLS). This method allows the determination of the relative amounts of the different carrageenans in a rapid and accurate manner.

Acylated flavonoids from pseudognaphalium species

Two new acylated flavonoids have been isolated from the resinous exudates of Pseudognaphalium robustum and Pseudognaphalium cheirantifolium. Their structures were elucidated by high-resolution spectroscopic methods as 5,7,8-trihydroxy-3-methoxyflavone 8-O-[(E)-2-methyl-2-butenoate] (1) and 5,7,8-trihydroxy-3, 6-dimethoxyflavone 8-O-[(E)-2-methyl-2-butenoate] (2).

Antimicrobial study of the resinous exudate and of diterpenoids isolated from Eupatorium salvia (Asteraceae).

The antimicrobial properties of the resinous exudate from twigs and leaves of Eupatorium salvia were tested against five gram-negative and five gram-positive bacteria. Comparison of the antimicrobial activities of 7-hydroxy-8(17)-labden-15-oic acid (salvic acid) and of its acetate, both compounds isolated from the plant, with that of the crude extract suggested that the latter ester derivative was the major active component in the exudate. These results validate the vernacular medicinal use of Eupatorium salvia as an antiseptic agent.