Antibacterial and antifungal activities of crude plant extracts from Colombian biodiversity

On a global scale, people have used plants to treat diseases and infections, and this has raised interest on the plant biodiversity potencial in the search of antimicrobial principles. In this work, 75 crude n-hexanes, dichloromethane and methanol extracts from the aerial parts of 25 plants belonging to four botanical families (Asteraceae, Euphorbiaceae, Rubiaceae and Solanaceae), collected at the Natural Regional Park Ucumari (Risaralda, Colombia), were evaluated for their antibacterial and antifungal activities by the agar well diffusion method. The antibacterial activities were assayed against two Gram-positive bacteria Staphylococcus aureus and Bacillus subtilis, and three Gram-negative ones named, Klebsiella pneumoniae, Escherichia coli and Pseudomonas aeruginosa. In addition, the same plant extracts were tested against the yeast Candida albicans and the fungi Aspergillus fumigatus and Fusarium solani. Overall, the plant extracts examined displayed better bactericide rather than fungicide activities. In general, the best antibacterial activity was showed by the plant extracts from the Rubiaceae family, followed in order by the extracts from the Euphorbiaceae and Solanaceae ones. It is important to emphasize the great activity displayed by the methanol extract of Alchornea coelophylla (Euphorbiaceae) that inhibited four out of five bacteria tested (B. Subtilis, P. aeruginosa, S. aureus and E. coli). Furthermore, the best Minimal Inhibitory Concentration for the extracts with antifungal activities were displayed by the dichloromethane extracts from Acalypha diversifolia and Euphorbia sp (Euphorbiaceae). The most susceptible fungus evaluated was F. Solani since 60% and 20% of the dichloromethane and methanol extracts evaluated inhibited the growth of this phytopathogenic fungus. The antimicrobial activity of the different plant extracts examined in this work could be related to the secondary metabolites contents and their interaction and susceptibility of pathogenic microorganism evaluated.

Alrededor del mundo, la gente ha usado las plantas para tratar enfermedades e infecciones, este potencial ha hecho que se incremente el interés en la biodiversidad vegetal como fuente de principios antimicrobianos. En este trabajo, se evaluaron 75 extractos crudos de n-hexano, diclorometano y metanol, obtenidos a partir de la parte aérea de 25 especies de plantas proveniente de cuatro familias botánicas (Asteraceae, Euphorbiaceae, Rubiaceae y Solanaceae), colectadas en el Parque Regional Natural Ucumari (Risaralda, Colombia); los cuales fueron evaluados por sus actividades antibacteriana y antifúngica a través del método de difusión en pozo. La actividad antibacteriana fue ensayada frente a las bacterias Gram-positivas Staphylococcus aureus y Bacillus subtilis, y las g-negativas Klebsiella pneumoniae, Escherichia coli y Pseudomonas aeruginosa. Adicionalmente, las mismas plantas fueron evaluadas frente a la levadura Candida albicans y los hongos Aspergillus fumigatus y Fusarium solani. En general, las plantas ensayadas mostraron mejor actividad antibacteriana que antifúngica; donde la familia Rubiaceae fue la que presentó mayor actividad antibacteriana, seguida por las familias Euphorbiaceae y Solanaceae. El extracto metanólico de Alchornea coelophylla (Euphorbiaceae) fue el que presentó mejor actividad antibacteriana al inhibir cuatro de las bacteria ensayadas (B. Subtilis, P. aeruginosa, S. aureus y E. coli); y los extractos de diclorometano de Acalypha diversifolia y Euphorbia sp. (Euphorbiaceae) fueron los que tuvieron la menor Concentración Mínima Inhibitoria en la actividad antifúngica. El hongo evaluado más susceptible fue F. Solani, el cual fue inhibido por el 60% y el 20% de los extractos de diclorometano y metanol, respectivamente. Se considera que la actividad biológica de estos extractos, se relaciona con los metabolitos secundarios que ellos contienen y las diferentes susceptibilidades de los microorganismos patogénicos evaluados.

Antioxidant activity of twenty five plants from Colombian biodiversity

The antioxidant activity of the crude n-hexane, dichloromethane, and methanol extracts from 25 species belonging to the Asteraceae, Euphorbiaceae, Rubiaceae, and Solanaceae families collected at natural reserves from the Eje Cafetero Ecorregión Colombia, were evaluated by using the spectrophotometric 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical-scavenging method. The strongest antioxidant activities were showed by the methanol and dichloromethane extracts from the Euphorbiaceae, Alchornea coelophylla (IC50 41.14 mg/l) and Acalypha platyphilla (IC50 111.99 mg/l), respectively. These two species had stronger DPPH radical scavenging activities than hydroquinone (IC50 151.19 mg/l), the positive control. The potential use of Colombian flora for their antioxidant activities is discussed.

Antibacterial, antifungal and cytotoxic activities of eight Asteraceae and two Rubiaceae plants from colombian biodiversity

Thirty crude extracts of eight plants belonging to Asteraceae and two to Rubiaceae families collected at different places from the Regional Natural Park Ucumarí (RNPU), Colombia, were tested for their antibacterial activity against two Gram-positive and two Gram-negative bacteria and three fungi. Both the antibacterial and the antimycotic activities were tested by the agar well diffusion method. The cytotoxic activity on the same plant extracts was determined through the brine shrimp lethality bioassay. The extracts from the Asteraceae family were more bioactive against Bacillus subtilis and Staphylococcus aureus. The extracts of both families studied were bioactive against the fungi Candida albicans and Fusarium solani. In addition, the extracts of Asteraceae species displayed the greatest cytotoxic activities. However, the most important specie in this research was Gonzalagunia rosea Standl (Rubiaceae) because of the strong and moderate activities of the methanol and dichloromethane extracts against C. albicans and F. solani, respectively; as well as the strong cytotoxic activity of the methanol extract. None of these ten plants has previously been reported for their biological activities.

Trinta extratos crus de oito plantas da família Asteraceae e a duas plantas da família Rubiaceae, coletadas em diferentes lugares do Parque Natural Regional Ucumarí (PNRU), Colombia, foram avaliadas quanto à atividade contra duas bactérias Gram-positivas, duas Gram-negativas e três fungos. As atividades antibacteriana e antimicótica foram determinadas pelo método de difusão em agar. A atividade citotóxica dos mesmos extratos foi determinada através do bioensaio de Artemia salina. Os extratos da família Asteraceae foram os mais bioativos contra Bacillus subtilis e Staphylococcus aureus. Os extratos de ambas famílias estudadas foram bioativos contra os fungos Candida albicans e Fusarium solani. Os extratos da família Asteraceae exibiram maior atividade citotóxica. A espécie mais importante desta pesquisa foi Gonzalagunia rosea Standl (Rubiaceae) devido à atividade intensa e moderada dos extratos de metanol e diclorometano contra F. solani e C. albicans, respectivamente, bem como a intensa atividade citotóxica do extrato metanólico. Não se encontraram estudos prévios acerca das atividades biológicas das dez plantas avaliadas nesse estudo.

In vitro inhibition of acetylcholinesterase by crude plant extracts from Colombian flora

The methanol extracts from five different plant families (Asteraceae, Euphorbiaceae, Melastomataceae, Rubiaceae, and Solanaceae) collected at Regional Natural Park Ucumarí (Colombia), were screened for their acetylcholinesterase inhibitory activity through the modified Ellman's spectrophotometric method. The best inhibitory activities on this study were shown by the extracts of Solanum leucocarpum Dunal (IC50 = 204.59 mg/l) and Witheringia coccoloboides (Damm) (IC50 = 220.68 mg/l), both plants belonging to the Solanaceae family.