Optically active ethyl ( R )-2-hydroxy-4-phenylbutanoate (( R )-HPBE), is a key component in the production of angiotensin-converting enzyme (ACE) inhibitors, which are essential for treating hypertension. However, the high cost of starting materials has been a barrier to the industrial synthesis of ( R )-HPBE. Herein, we have established for the first time a four-step enzymatic reaction in continuous flow for the efficient synthesis of ( R )-HPBE from inexpensive benzaldehyde and pyruvic acid. This route also overcomes the issues of chemical disequilibrium and incompatibility of reaction conditions that are common in multi-enzyme cascades. The immobilization methods for aldolase/ene-reductase/keto-reductase were developed, and the immobilized enzymes were initially used in three individual flow modules to produce ( R )-2-hydroxy-4-phenylbutanoic acid (( R )-HPB), achieving high space–time yields of 3103 g (OPBEA) L −1 d −1 , 1685 g (OPBE) L −1 d −1 and 1709 g ( R )-HPB L −1 d −1 respectively. Moreover, integrating three modules in continuous flow achieved a space–time yield of about 350 g ( R )-HPB L −1 d −1 after 108 h, and maintained high operational stability with a conversion of >99 % and a product ee of >99.9 % after 192 h. Subsequently, the ethyl esterification of ( R )-HPB as the fourth module for producing ( R )-HPBE obtained a high space–time yield of 2117 g ( R )-HPBE L −1 d −1 , marking a substantial 74.5-fold increase over the batch system.
Hypertension has become a growing public health concern worldwide. In fact, hypertension is commonly associated with increased morbidity and mortality. Currently, oligonucleotide drugs have proven to be promising therapeutic agents for various diseases. In the present study, we aimed to demonstrate that a herbal small RNA (sRNA), XKC-sRNA-h3 (B55710460, F221. I000082.B11), exhibits potent antihypertensive effects by targeting angiotensin-converting enzyme (ACE) in mice. When compared with captopril, oral administration of the sphingosine (d18:1)-XKC-sRNA-h3 bencaosome more effectively prevented angiotensin II-induced hypertensive cardiac damage and alleviated kidney injury in mice. Such findings indicated that XKC-sRNA-h3 may be a novel orally available ACE inhibitor type oligonucleotide drug for hypertension.
LVLPGE is an angiotensin-converting enzyme (ACE) inhibitory peptide extracted from broccoli protein hydrolysates. The antihypertensive mechanism of LVLPGE was explored in the present study. The results indicated that the IC 50 value of LVLPGE was 19.49 μM, and its binding to ACE occurred via a static fluorescence quenching involving the secondary structure changes of ACE. In addition, LVLPGE competitively bound to the active site of ACE through hydrogen bonding. Furthermore, LVLPGE markedly enhanced the levels of the vasodilator nitric oxide (NO) in the Ang I-induced HUVECs model, suppressed the expression of vasoconstrictor endothelin-1 (ET-1), and increased the phosphorylation of eNOS. Moreover, LVLPGE was found to enhance the production of cyclic guanosine monophosphate (cGMP), which leading to a subsequent decrease in intracellular calcium concentration, ultimately facilitating the relaxation of vascular smooth muscles and lowering the blood pressure. These results demonstrated that LVLPGE achieves the antihypertensive effects by inhibiting ACE activity and activating the eNOS/NO/cGMP signaling pathway. This study provides new insights into the antihypertensive mechanism of LVLPGE and contributes to the high-value utilization of broccoli resources.
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