In Vitro Screening for Anti-Acetylcholinesterase and Antioxidant Activities of Hottonia palustris L. Extracts and Their Unusual Flavonoids

Hottonia palustris L. is from the genus Hottonia (Primulaceae), and the understanding of its phytochemical and pharmacological properties is limited. In this study, the use of chromatographic techniques led to the isolation of a further eleven compounds, including three new flavonoids: 2',5-dihydroxyflavone 2'-O-β-glucopyranoside, 5,6-dihydroxyflavone 6-O-(6"-O-glucopyranosyl)-β-glucopyranoside (hottonioside A), and 4',5,7-trihydroxyflavone 7-O-(2"-O-β-glucuronide)-β-glucopyranoside. Their structures were determined using extensive 1D and 2D NMR data and mass spectrometry (HRMS). The qualitative assessment of the chemical composition of the investigated extracts and fractions was performed using the LC-HRMS technique. Furthermore, the antioxidant potential of extracts, fractions, and compounds and their ability to inhibit acetylcholinesterase were also evaluated. Thus, we may conclude that the observed biological effects are the result of the presence of many biologically active compounds, of which dibenzoylmethane is the most active. Therefore, H. palustris is a source of substances with desirable properties in the prevention and treatment of neurodegenerative diseases.

Novel 2-amino-1,4-dihydropyridine calcium antagonists. I. Synthesis and antihypertensive effects of 2-amino-1,4-dihydropyridine derivatives having nitroxy-alkoxycarbonyl groups at 3- and/or 5-position

Novel 2-amino-1,4-dihydropyridine derivatives, which contain nitroxy-alkoxycarbonyl groups at the 3- and/or 5-position, were synthesized and their pharmaceutical effect was evaluated in spontaneously hypertensive rats. The structure-activity relationships are discussed in terms of potency, onset-rapidity, and duration of antihypertensive activity. Remarkably prolonged duration of antihypertensive action was observed when a tertiary amino group was introduced on either side of an ester chain.