Gabriela Rojas

Antimicrobial evaluation of some plants used in Mexican traditional medicine for the treatment of infectious diseases

Twelve methanolic plant extracts from botanical species used in traditional medicine in Morelos, México to cure infectious diseases have been subjected to a screening study to detect potential antimicrobial activity against Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa and Candida albicans. The antimicrobial activity of the products was evaluated using colonies growing in solid medium, establishing the minimal concentration required to inhibit their in vitro growth (MIC). The results showed that extracts from Eucalyptus globolus Labill, Punica granatum L., Artemisia mexicana Wild., and Bocconia arborea Watt. possess strong in vitro antimicrobial activity against the tested microorganisms.

Antimicrobial evaluation of certain plants used in Mexican traditional medicine for the treatment of respiratory diseases

Eighteen crude extracts, including six hexanic, six chloroformic and six methanolic from six different plant species used in Mexican traditional medicine for the treatment of respiratory infections, were evaluated for potential antimicrobial activity against Staphylococcus aureus, Enterococcus faecalis, Streptococcus pneumoniae, Streptococcus pyogenes, Escherichia coli, and Candida albicans. The minimal inhibitory concentration was determined for each extract using a two-fold dilution assay. The results showed that 16 crude extracts (89%) exhibited antimicrobial activity against at least one of the microorganisms tested at concentrations of 5 mg/ml or below. The extracts from Gnaphalium oxyphyllum, Gnaphalium americanum, and Crescentia alata possessed strong antimicrobial activity against the pathogens tested.

Antifungal and antibacterial activity of four selected mexican medicinal plants

Abstract The antifungal and antibacterial activity of 10 crude extracts from four different species, all of them used in Mexican folk medicine for the treatment of infectious diseases, were tested in vitro. for antimicrobial activity against Staphylococcus aureus., Streptococcus faecalis., Escherichia coli, Klebsiella pneumoniae., Salmonella typhi., Candida albicans., Trichophyton mentagrophytes., and Trichophyton rubrum.. All extracts from the above plants showed some degree of antimicrobial activity against at least two microorganisms tested. The strongest antibacterial activity was found in the water extract of Hibiscus sabdariffa. and the methanol extract of Lysiloma acapulcensis., whereas the methanol extract from Loeselia mexicana. showed the best antifungal activity against dermatophytes.

In vitro propagation ofMimosa tenuiflora (Willd.) Poiret, a Mexican medicinal tree

SummaryMimosa tenuiflora (Willd.) Poiret (Leguminosae) was micropropagated throughin vitro culture of axillary buds on Murashige and Skoog (MS) medium. Shoot formation was achieved when the media were supplemented with 0.1 mg.L−1 IAA + 3 mg.L−1 KN.In vitro rooting of regenerated shoots was achieved when 0.1 mg.L−1 KN was combined with 1 mg.L−1 IBA in the absence of IAA. Ninety-four percent of the rooted plants were succesfully adapted to field conditions and grown in the soil. A total of 180 trees grown under these conditions were obtained over a one-year period.

In vitro antifungal activity of coumarin extracted from Loeselia mexicana Brand

The bis‐coumarin daphnoretin and its monomeric precursors scopoletin and umbelliferone were isolated for the first time from the aerial part of Loeselia mexicana Brand (a vegetal species used in Mexican traditional medicine) using chromatographic techniques. The structures of these compounds were determined by 1H and 13C NMR analyses. These coumarins were evaluated for in vitro antifungal activity. The three compounds tested showed significant antifungal activity.

Large-scale cultivation ofSolanum chrysotrichum cells: Production of the antifungal saponin SC-1 in 10-I airlift bioreactors

Cells of two different cell lines:ccvx (cotyledon derived) andccvz (hypocotyl derived) ofSolanum chrysotrichum were cultivated in 10-1 airlift bioreactors for the production of the human antimycotic compound SC-1. When using 3 g l-1 dry weight inoculum in a batch culture, higher levels of biomass were achieved with theccvx cell line (14.6 g l-1) than withccvz (7.7 g l-1), resulting in 23 and 12 mg g-1 of SC-1 after 17 days in culture forccvx andccvz, respectively. The maximum productivity of SC-1 in bioreactors was 0.025 g l-1 day-1 after 9 days in culture. When using a draw-fill mode, the productivity increased by 60% to a value of 0.041 g l-1 day, 4 days after 50% of the cell suspension was removed and replaced with fresh medium. This latter bioreactor system is a feasible alternative for the production of the antimycotic metabolite ofS. chrysotrichum on a large scale.

Studies on Mimosa tenuiflora callus culture. Interaction of kinetin and 2,4 dichlorophenoxyacetic acid in initiation and growth

SummaryInfluence of growth regulators during initiation ofMimosa tenuiflora calli tissue varied according to explant source. KN (Kinetin) affected hypocotyls, while an interaction between different combinations of 2,41) (2,4 dichlorophenoxyacetic acid) and KN induced cotyledons,stems and leaves. Calli growth after 60 days was influenced by both hormones in cotyledons, by 2,4D in hypocotils and by an interaction of the two regulators in stems and leaves. The indole alkaloid Nb-Nb dimethyltryptamine was found to be present in some cultures at a level comparable to that of the source plant.

In vitro culture of Montanoa tomentosa for the production of diterpenic acids

Following a solid phase extraction, GC-MS and GC-FID procedures, the production of three kaurane derivatives (grandiflorenic, kaurenoic and monoginoic acids) was detected in callus and cell suspension batch cultures of Montanoa tomentosa. From different hormonal combinations, the addition of 0.5 mg 2,4-dichlorophenoxyacetic acid l−1 + 2 mg kinetin l−1 increased the accumulation of total kaurenoids in 6 months old calluses to 2.1 mg g−1 dry weight and in cell suspensions cultures up to 0.76 mg g−1 dry weight. Monoginoic acid, which has not been detected before in leaves of wild plants, accumulated in both in vitro systems.

Recent progress in biotechnology of Mexican medicinal plants

Based on traditional medicinal knowledge, it was possible to identify the plant species Solanum chrysotrichum as the source of a new antimycotic agent designated SC-1. Cell suspension batch cultures from this plant were established in shake flasks, in which the production of SC-1 was optimized, reaching values fifty times higher than those registered in field grown plants. Large-scale cultivation of the active biomass from S. chrysotrichum was established in 10 l airlift bioreactors, and productivity levels of SC-1 were increased by 60% when using a draw-fill mode in the bioreactors.