Biofilm inhibition activity of traditional medicinal plants from Northwestern Argentina against native pathogen and environmental microorganisms

Abstract: INTRODUCTION: Plants have been commonly used in popular medicine of most cultures for the treatment of disease. The in vitro antimicrobial activity of certain Argentine plants used in traditional medicine has been reported. The aim of this study was to investigate the antimicrobial, anti-biofilm, and anti-cell adherence activities of native plants (Larrea divaricata, Tagetes minuta, Tessaria absinthioides, Lycium chilense, and Schinus fasciculatus) collected in northwestern Argentina. METHODS: The activities of the five plant species were evaluated in Bacillus strains and clinical strains of coagulase-negative Staphylococcus isolated from northwestern Argentina and identified by 16S rDNA. RESULT: Lycium chilense and Schinus fasciculatus were the most effective antimicrobial plant extracts (15.62µg/ml and 62.50µg/ml for Staphylococcus sp. Mcr1 and Bacillus sp. Mcn4, respectively). The highest (66%) anti-biofilm activity against Bacillus sp. Mcn4 was observed with T. absinthioides and L. divaricate extracts. The highest (68%) anti-biofilm activity against Staphylococcus sp. Mcr1 was observed with L. chilense extract. T. minuta, T. absinthioides, and L. divaricata showed percentages of anti-biofilm activity of between 55% and 62%. The anti-adherence effects of T. minuta and L. chilense observed in Bacillus sp. Mcn4 reflected a difference of only 22% and 10%, respectively, between anti-adherence and biofilm inhibition. Thus, the inhibition of biofilm could be related to cell adherence. In Staphylococcus sp. Mcr1, all plant extracts produced low anti-adherence percentages. CONCLUSION: These five species may represent a source of alternative drugs derived from plant extracts, based on ethnobotanical knowledge from northwest Argentina.

Larvicidal activity of crude extracts from Larrea cuneifolia (Zygophyllaceae) and of its metabolite nordihydroguaiaretic acid against the vector Culex quinquefasciatus (Diptera: Culicidae)

INTRODUCTION: The aim of the present study was to analyze the larvicidal activity of different crude extracts of Larrea cuneifolia and its most abundant lignan, nordihydroguaiaretic acid (NDGA), against Culex quinquefasciatus. METHODS: Chloroform, methanol, and aqueous extracts from L. cuneifolia and NDGA were tested against larvae of Cx. quinquefasciatus under laboratory conditions. RESULTS: The chloroform extract showed the highest larvicidal effect, with an estimated LC50 of 0.062 mg/ml. NDGA also demonstrated significant larvicidal activity with an estimated LC50 of 0.092 mg/ml. CONCLUSIONS: These results indicate that the chloroform extract of L. cuneifolia and NDGA are promising insecticides of botanical origin that could be useful for controlling Cx. quinquefasciatus.

Larrea divaricata Cav: scientific evidence showing its beneficial effects and its wide potential application / Larrea divaricata Cav: evidencia específica mostrando sus efectos beneficiosos y su amplia aplicación potencial

Larrea divaricata Cav. (jarilla) (Zygophyllaceae) is used in Argentinean folk medicine. It contains nordihydroguaiaretic acid (NDGA), a lignan with nefrotoxic and hepatotoxic effects. The presence of NDGA converts controversial the use of L. divaricata. The amount of NDGA is higher in alcoholic extracts than in aqueous extracts (AE). The last 20 years had a great advance on the use of AE to treat different conditions in a safe manner. In this review, we present the scientific results tending to confirm the potential beneficial effects of the AE on human health. The anti-proliferative effects of AE of L. divaricata have been assayed on a tumor lymphoid line (BW 5147) and the pathways involved in such effects were described. The anti-microbial activity was determined by tests for bacteria and fungus. The anti-inflammatory activity was assayed by using carrageen and TPA induced-inflammation tests. The Immunomodulatory effects were investigated ¯in vivo and ¯in vitro on mice. Sub-fractions of aqueous extracts were obtained and analyzed. The immunogenicity of proteins from crude AE was characterized and antioxidant and nutritional activity were studied. The effect of an AE on hair loss was assayed. In summary, AE from L. divaricata has pharmacological activities including anti-microbial, anti-inflammatory, anti-cancer effects.

Larrea divaricata Cav. (Jarilla) (Zygophyllaceae) es utilizada en medicina popular Argentina. Contiene ácido nordihidroguaiarético (NDGA), un lignano con efectos nefrotóxicos y hepatotóxicos. La presencia de NDGA hace controvertido el uso de L. divaricata. La cantidad de NDGA es mayor en extractos alcohólicos que en extractos acuosos (EA). Los últimos 20 años han tenido un gran avance en el uso de EA para el tratamiento de diferentes condiciones en forma segura. En esta revisión se presentan resultados científicos que confirman los efectos potencialmente beneficiosos de los EA sobre la salud humana. Los efectos anti-proliferativos se han ensayado en una línea de tumor linfoide, así como los mecanismos involucrados. La actividad anti-microbiana se determinó usando pruebas para bacterias y hongos. La actividad anti-inflamatoria fue evaluada mediante el uso de inflamación inducida por carragenina y TPA. Los efectos inmunomoduladores fueron investigados "in vivo" e "in vitro" en ratones. Sub-fracciones de los EA fueron obtenidos y analizados. La inmunogenicidad de las proteínas del EA crudo se caracterizaron y se estudiaron las actividades antioxidantes nutricionales. Además, se ensayó el efecto del EA en la caída del cabello. En resumen, los EA de L. divaricata presentan actividades farmacológicas como por ejemplo, anti-microbiana, anti-inflamatoria y efectos anti-cancerígenos.