RESUMO
Leptohyptis macrostachys, previously known as Hyptis macrostachys Benth., is used in folk medicine to relieve the symptoms of asthma, cough, and bronchitis. Recently, we showed that the ethanol extract obtained from Leptohyptis macrostachys has selective spasmolytic activity on guinea pig ileum. Therefore, the aim of this study was to characterize the spasmolytic mechanism of this extract, investigated whether it presents toxicological and antidiarrheal activities. Therefore, the crude ethanolic extract of Leptohyptis macrostachys was analyzed by high-performance liquid chromatographic-diode array detection (HPLC-DAD). The spasmolytic effect was evaluated on guinea pig ileum, toxicological activity using rats and antidiarrheal activity using male and female mice. In HPLC-DAD analysis, Rosmarinic acid (5.44%) was the most abundant phenolic compound, being considered as a chemical marker. The spasmolytic potency of the extract on histamine-induced contraction was reduced in the presence of 1 mM TEA+, a selective big-conductance K+ channels blocker (BKCa). The extract produces a dose-dependent antidiarrheal activity, inhibiting equipotently defecation frequency and liquid stool formation. In addition, the extract has inhibited in a dose-dependent manner both castor oil-induced intestinal transit and intestinal fluid content. Thus, the spasmolytic activity of the extract involves positive modulation of BKCa and its antidiarrheal activity is related to inhibition of intestinal motility and secretion.
RESUMO
Flavonoid compounds are widely used as natural protective species, which can act as anti-inflammatory, antioxidant, anticoagulant, antihypertensive and antitumor agents. This study set out to investigate the probable pharmacological activities, along with the antibacterial and antioxidant effects, of flavone and its hydroxy derivatives: 3-hydroxyflavone, 5-hydroxyflavone and 6-hydroxyflavone. To do so, we investigated their pharmacological characteristics, using in silico tests that indicate likelihood of activity or inactivity, with the PASS online software, and the antimicrobial potential against Gram positive and Gram negative bacteria was also analyzed, including bacteria of clinical importance. We also tested for oxidant and antioxidant potential in these molecules in the presence of reactive oxygen species (ROS) and phenylhydrazine (Ph). The results revealed the following characteristics: pharmacological activities for the flavonoids as agonists of cell membrane integrity and as permeability inhibitors, as antagonists of anaphylatoxin receptors, as inhibitors of both kinase and peroxidase, and as having both antimutagenic capacity and vaso-protective potential. All of the flavonoids exhibited moderate antibacterial activity against Gram positive and Gram negative strains, with the flavones being bactericidal at 200 µg/mL for the strains of P. aeruginosa ATCC 8027, S. aureus ATCC 25619 and E. coli 104; the other flavonoids revealed bacteriostatic action. The substances did not promote erythrocyte oxidation and behaved as sequestrators and antioxidants of hydrogen peroxide (H2O2) and phenylhydrazine (Ph). It was concluded that the analyzed compounds have various pharmacological activities in accordance with the predictions of PASS online, as their antibacterial and antioxidant activities were confirmed. The study also helps to consolidate the use of computational chemistry in silico tools to guide new drug search and discovery protocols.
