Antimicrobial Activity of the Constituents of Dalbergia tonkinensis and Structural-Bioactive Highlights

Abstract

The vulnerable plant Dalbergia tonkinensis Prain, is a rare species, native to Vietnam. Phytochemical investigations and biological evaluations of this species are quite limited. Antimicrobial screening has suggested that, at the low dose of 1.0 mg/mL, the methanol extracts of the leaf, stem bark, and root, as well as chloroform fraction of heartwood can serve as useful sources against seven gram-positive skin microbacteria, Bacillus cereus (ATCC27522), Escherichia coli (JM109), Staphylococcus aureus (ATCC25923), Staphylococcus epidermidis (ATCC14990), Streptococcus pneumonia (ATCC49619), Streptococcus pyogenes (ATCC12344), and Vibrio parahaemolyticus (RIMD2210010), and four oral gram-positive microbacteria Streptococcus mutans (ATCC 25175), Streptococcus mitis (ATCC903), Streptococcus sobrinus (ATCC 33478), and Porphyromonas gingivalis (ATCC33277), with an inhibitory percentage of 60-80% growth for several strains Bacillus cereus, Escherichia coli, and Streptococcus pneumonia. We further assessed antimicrobial activities of the enriched diverse flavonoids from chloroform fraction of its heartwood. Extensive structural activity relationship studies showed structure function closely related to the antimicrobial activity, in which methoxylation at C-2’, and 4’ in isoflavanones, hydroxylation at C-3’ in flavones, substitution at C-5 in isoflavones, and lactone opened ring in neoflavonoids were found to increase the effective inhibitions. In the second antimicrobial assessment, the isolated flavonoid liquiritigenin showed the MIC values of 50, and 100 μg/mL against the microbacterial strains Staphylococcus aureus subsp. aureus (ATCC 11632), and Aspergillus niger (439), respectively, whereas the MIC value of 100 μg/mL was assignable to biochanin A against microbacterium Staphylococcus aureus subsp. aureus.

Antioxidation of 2-phenylbenzofuran derivatives: structural-electronic effects and mechanisms

“…The structural differences, molecular size, stereochemistry, length of atomic bonds, and extra-or intramolecular hydrogen bonds, especially in terms of the behavior of hydroxyl groups, can be seen as basic characteristics to prove the pharmacological effects of a studied molecule. 3 As a consequence, a comprehensive analysis of structural and electronic descriptors of 2-phenylbenzofuran derivatives 1-16 is always recognized as the best way to forecast the radical scavenging capacity, along with the three antioxidant mechanisms. In the current paper, we provide computational outcomes for all studied compounds 1-16 at the DFT-B3LYP/6-311++G(d,p) level.…”

“…2 Natural products, especially compounds isolated from plants, have historically proven their positive values in terms of therapeutic potency, whereas the employment of synthetic compounds is accompanied by high costs, a long duration of treatment, adverse effects and limitations in drug efficacy. 3 Thus, scientic approaches seeking new drug lead compounds are always expected.…”

Genus Miliusa: A Review of Phytochemistry and Pharmacology

“…The global health problem in developing countries is becoming increasingly involved in growing and expanding of microbacteria. Historical records have accumulated evidence showing that the use of traditional antibiotics, which are derived from synthetic substances, is always accompanied by a long duration of treatment, high cost, and drug resistance [48]. Therefore, calls for new antibiotic drugs from natural sources in the fight against multidrug-resistant bacteria are always strategy.…”

Vasorelaxing Activity of R-(−)-3′-Hydroxy-2,4,5-trimethoxydalbergiquinol from Dalbergia tonkinensis: Involvement of Smooth Muscle CaV1.2 Channels

“…A phytochemical study on this species has led to the identification of different types of compounds [17], including flavonoids, isoflavonoids, and neoflavonoids, endowed with various, interesting, pharmacological activities [18][19][20][21][22][23][24]. Curiously, the term "neoflavonoids" was first proposed by Ollis in 1966 when he found that various dalbergiones and dalbergiquinols are characteristic of the Dalbergia species [25].…”