D-phenyllactic Acid Research Articles

Two Novel Hepatocellular Carcinoma Cycle Inhibitory Cyclodepsipeptides from a Hydrothermal Vent Crab-Associated Fungus Aspergillus clavatus C2WU

Two novel cyclodepsipeptides containing an unusual anthranilic acid dimer and a d-phenyllactic acid residues, clavatustides A (1) and B (2), were identified from cultured mycelia and broth of Aspergillus clavatus C2WU isolated from Xenograpsus testudinatus, which lives at extreme, toxic habitat around the sulphur-rich hydrothermal vents in Taiwan Kueishantao. This is the first example of cyclopeptides containing an anthranilic acid dimer in natural products, and the first report of microbial secondary metabolites from the hydrothermal vent crab. Clavatustides A (1) and B (2) suppressed the proliferation of hepatocellular carcinoma (HCC) cell lines (HepG2, SMMC-7721 and Bel-7402) in a dose-dependent manner, and induced an accumulation of HepG2 cells in G1 phase and reduction of cells in S phase.

Enantiomer separation of phenyllactic acid by HPLC with Hp-β-cyclodextrin as chiral mobile phase additive

In our current research work, a sensitive, specific, and economic HPLC method has been developed for the separation of phenyllactic acid (PLA) enantiomers. The effects of cyclodextrin (CD) type, column temperature, buffer pH, methanol content and CD concentration on enantioselective separation were investigated. Baseline chromatographic separation was achieved on an Inertsil ODS-SP (150 × 4.6 mm, i.d. 5 μm) column with HP-β-CD as chiral mobile phase additive. The LOD and LOQ for d-phenyllactic acid were 0.3 and 0.7 μg/mL, respectively. A good linear relationship was obtained in the concentration range of 0.71–5.13 μg/mL with r2 >0.999 for d-PLA. The percentage recovery of the d-PLA ranged from 94.1 to 103.2 in l-PLA. This method is simple and cost-saving, and could be easily applied for chiral discrimination and determination of the racemic PLA in an enantioselective study in quality control laboratory.

Solution structures by NMR of a novel antifungal drug: Petriellin A

Petriellin A is a novel cyclic depsipeptide antifungal compound consisting of nine l-configured residues, one d-phenyllactic acid (PhLac) and three unknown chiral centres: two N-methyl-threonines (MeThr1 & MeThr2) and one N-methyl-isoleucine (MeIle). NMR experiments including 2D ROESY, NOESY along with structural and energy calculations predicted that the unknown chiral centres were all l-configured, which was later verified chemically. Simulated annealing, dynamics calculations and minimisation processes showed Petriellin A to have a folded "C-shaped" structure.

Efficiency of Phenylpyruvic and Phenyllactic Acids as Substitutes for Phenylalanine in the Diet of the Growing Rat

Male weanling albino rats fed a diet containing all nutrients for optimal growth, including 45.4 mumoles of phenylalanine/g, gained weight at an average of 6.5 g/day. Removal of phenylalanine caused an average weight loss of 1.1 g/day. Addition of graduated increments of phenylalanine led to progressive increases in growth rate; the increases being proportional to the dietary content of this amino acid. When phenylpyruvic or L-phenyllactic acids were added isonitrogenously to the phenyl-alanine-free diet, growth rate also increased. Percent efficiency of these amino acid analogues as dietary substitutes for phenylalanine, calculated as (see article) varied from 50% to 70% for phenylpyruvic acid and 65% to 95% for L-phenyllactic acid. Efficiency increased as dose of analogue increased. Non-isonitrogenous substitution did not change growth rates. Supplementation with a megadose of pyridoxine did not increase the efficiency of phenylpyruvic acid. D-phenyllactic acid and cinnamic acid were completely ineffective as substitutes for phenylalanine. When tyrosine was withdrawn from the diet, efficiency of phenylpyruvic acid was 70% at several doses. The efficiency of L-phenyllactic acid was 65 to 40%, decreasing with increasing dose.