ABSTRACT
The antimycobacterial activity of Scutia buxifolia Reissek, Rhamnaceae, leaves extracts and fractions were evaluated for the first time. Four compounds were identified, flavonoids (quercetin and quercitrin) and phenolic acids (gallic and caffeic acids) and quantified by HPLC-DAD. Promising anti-Mycobacterium smegmatis activity was observed with ethyl acetate extract (MIC 312.50 µg/mL) and their fractions (MIC values ranging from 78.12 to above 312.50 µg/mL). The fractions III and VI of S. buxifolia leaves showed a high level of activity against M. smegmatis (MIC 78.12 and 156.25 µg/mL, respectively), M. tuberculosis (MIC 156.25 µg/mL) and M. avium (MIC 312.50 µg/mL), whereas to the other fractions the values varied from 312.50 to 1250.00 µg/mL against these strains. The better MIC result was associated with two fractions that contain bigger amounts of quercetin, quercitrin, gallic and caffeic acids. The results provided evidence that the studied plants fractions might be potential sources of new antimicrobial drug.
ABSTRACT
Ilex paraguariensis is widely used in South Brazil, Argentinna, Paraguay and Uruguay as a beverage (maté) and also as a traditional medicinal plant. During the past ten years, we have systematically studied the saponins of the leaves of genuine maté (Ilex paraguariensis) and the other Ilex species reported as adulterants, searching for chemical differences. Here we give a brief account of the elucidated saponin structures. Ilex paraguariensis and Ilex dumosa can be considered as saponin rich species, containing between 5-10 per cent of crude saponins in the leaves, in opposition to other species that showed a lower saponin content. All the saponins from Ilex paraguariensis leaves identified up to now are glycosides of ursolic or oleanolic acid. From Ilex dumosa, the most frequently quoted maté adulterant, we have isolated and elucidated the structures of ten saponins, almost all of them being glycosides of oleanolic acid and one of 29-hydroxyoleanolic acid. In comparison, the saponin pattern for the other South American Ilex species investigated up to now is different. The saponins from I. pseudobuxus, I. argentina, I. taubertiana and I. theezans all have the aglycones derived from the 19alpha-hydroxyursolic acid. Saponins containing this type of aglycone were not found in the leaves of Ilex paraguariensis and Ilex dumosa. These are important features, that may have taxonomical significance. Furthermore, this knowledge is necessary to develop methodologies for quality control of maté products and to identify the compounds involved in the tast, flavor and pharmacological properties.