Identification, Characterization and Antihypertensive Effect In Vivo of a Novel ACE-Inhibitory Heptapeptide from Defatted Areca Nut Kernel Globulin Hydrolysates.

The areca (Areca catechu L.) nut kernel (ANK) is a good potential protein source for its high protein content of 9.89-14.62 g/100 g and a high yield of around 300,000 tons per year in China. However, utilization of the areca nut kernel is limited. To expand the usage of ANK in pharmaceutical or foods industries, areca nut kernel globulin was extracted and angiotensin-I converting enzyme (ACE) inhibition peptides were prepared and identified using gel chromatography, reversed phase HPLC separation, UPLC-ESI-MS/MS analysis and in silico screening. Finally, a novel ACE-inhibitory heptapeptide (Ala-Pro-Lys-Ile-Glu-Glu-Val) was identified and chemically synthesized. The combination pattern between APKIEEV and ACE, and the inhibition kinetics, antihypertensive effect and endothlein-1 inhibition activity of APKIEEV were studied. The results of the molecular docking demonstrated that APKIEEV could bind to four active sites (not the key active sites) of ACE via short hydrogen bonds and demonstrated high ACE-inhibitory activity (IC50: 550.41 µmol/L). Moreover, APKIEEV exhibited a significantly lowering effect on both the systolic blood pressure and diastolic blood pressure of spontaneously hypertensive rats, and had considerable suppression ability on intracellular endothelin-1. These results highlight the potential usage of APKIEEV as ingredients of antihypertensive drugs or functional foods.

[Effects of moxibustion on acupoints at "opening" time on testicular tissue apoptosis in aging rats].

OBJECTIVE: To observe the effect of "lingguibafa" moxibustion at "opening" time on the level of superoxide dismutase(SOD), malondialdehyde(MDA), the protein expressions of B-cell lymphoma-2 (Bcl-2) and Bcl-2 associated X protein (Bax) in aging model rats. METHODS: SD rats were randomly divided into blank control, model and lingguibafa groups, with 8 rats in each group. The aging model was established by daily intraperitoneal injection of D-galactose (500 mg/kg) for 42 consecutive days. After successful modeling, moxibustion intervention was applied at"lingguibafa" acupoints, 3 moxa-cone for each acupoint, once a day for 28 consecutive days. The contents of SOD and MDA in serum were detected by ELISA. Morphological changes of testicular tissue and the number of Leydig cells were observed after HE staining. Apoptosis rate of testicular cells was detected by TUNEL staining. The protein expression levels of Bcl-2 and Bax in testis were detected by Western blot. RESULTS: Compared with the blank control group, the SOD content in the serum, the number of testicular Leydig cells, the expression level of Bcl-2 protein in testis were significantly decreased (P<0.01) in the model group, while the MDA content in the serum, the apoptosis rate of testicular cells and the expression level of Bax protein in testis were significantly increased (P<0.01). Compared with the model group, the SOD content in serum, the number of testicular Leydig cells, the Bcl-2 protein expression in testis were significantly increased (P<0.01), while the MDA content in serum, the apoptosis rate of testicular cells, the expression level of Bax protein in testis were significantly decreased(P<0.01) in the lingguibafa group. CONCLUSION: Moxibustion on acupoints at "opening" time can delay testicular aging, and the mechanism may be related to balancing the metabolism of free radicals, reducing oxidative damage, and inhibiting the apoptosis of testicular cells.