Process Optimization, Structural Characterization, and Calcium Release Rate Evaluation of Mung Bean Peptides-Calcium Chelate.

To reduce grievous ecological environment pollution and protein resource waste during mung bean starch production, mung bean peptides-calcium chelate (MBP-Ca) was synthesized as a novel and efficient calcium supplement. Under the optimal conditions (pH = 6, temperature = 45 °C, mass ratio of mung bean peptides (MBP)/CaCl2 = 4:1, MBP concentration = 20 mg/mL, time = 60 min), the obtained MBP-Ca achieved a calcium chelating rate of 86.26%. MBP-Ca, different from MBP, was a new compound rich in glutamic acid (32.74%) and aspartic acid (15.10%). Calcium ions could bind to MBP mainly through carboxyl oxygen, carbonyl oxygen, and amino nitrogen atoms to form MBP-Ca. Calcium ions-induced intra- and intermolecular interactions caused the folding and aggregation of MBP. After the chelation reaction between calcium ions and MBP, the percentage of ß-sheet in the secondary structure of MBP increased by 1.90%, the size of the peptides increased by 124.42 nm, and the dense and smooth surface structure of MBP was transformed into fragmented and coarse blocks. Under different temperatures, pH, and gastrointestinal simulated digestion conditions, MBP-Ca exhibited an increased calcium release rate compared with the conventional calcium supplement CaCl2. Overall, MBP-Ca showed promise as an alternative dietary calcium supplement with good calcium absorption and bioavailability.

Non-targeted analysis of vulgarisins by using collisional dissociation mass spectrometry for the discovery of analogues from Prunella vulgaris.

Vulgarisins are members of diterpenoids with rare 5/6/4/5 ring skeleton from Prunella vulgaris Linn. (P. vulgaris). Their molecular scaffolds comprise different hydroxylation and degree of esterification. Vulgarisins have attracted many attentions in the fields of food and medicine for their potent bioactivities. Firstly, four reference compounds were analyzed by higher-energy collisional dissociation mass spectrometry (HCD MS/MS) and the fragmentation patterns for molecular scaffold were summarized. And then, a high-performance liquid chromatography/electrospray ionization/high-resolution mass spectrometry (HPLC-ESI-HR-MS) method was adopted to investigate the P. vulgaris extracts. Finally, the proposed analysis results were successfully applied to facilitate the discovery of the vulgarisins analogues from P. vulgaris. For the four reference compounds, the sodium adduct was the predominate ion in full scan. A specific fragmentation pathway of [M+Na]+ ions leads to produce diagnostic ions of vulgarisins at m/z 325 under HCD, which was formed through consecutive-side chains lost. Twenty-three diterpenoids, including 18 vulgarisins analogues, were identified or tentatively characterized in the botanical extracts of P. vulgaris based on their elemental constituents and characteristic fragment ion profiles. Two new vulgarisins analogues in the plant were isolated and their structures were illustrated based on extensive spectroscopic analysis using 1D and 2D nuclear magnetic resonance (NMR) spectroscopy. The HCD MS/MS method, including the profiles of the diagnostic ions induced by characteristic fragmentation, is an effective technique for the discovery of vulgarisins analogues in P. vulgaris. The expected fragmentation pattern knowledge will also facilitate the analysis of other natural products.

The limonoids and their antitobacco mosaic virus (TMV) activities from Munronia unifoliolata Oliv.

Five new limonoids, named munronoids K-O (1-5), together with three known limonoids were isolated from Munronia unifoliola Oliv. These limonoids were involved in the skeletons of evodulone, gedunin, and peieurianin types of limonoids, and their structures were established on the basis of spectroscopic data. Compound 5 featuring a γ-lactone ring instead of the ß-substituted furan ring was found in the peieurianin type for the first time. The antitobacco mosaic virus (anti-TMV) activities of compounds 1-8 were also evaluated with half-leaf, enzyme-linked immunosorbent assay, and Western blot methods, and limonoids 1, 5, and 8 showed stronger anti-TMV treatment activities than the positive control ningnanmycin. Six compounds (1-5 and 8) exhibited infection inhibition activities against TMV.

[Studies on the chemical constituents from Euphorbia chrysocoma].

OBJECTIVE: To study the chemical constituents from the aerial part of Euphorbia chrysocoma. METHODS: All compounds were isolated and purified by many methods, including siliga gel and reversed phase RP-18 column chromatographies, preparative thin layer chromatography, Sephadex LH-20, and recrystallization. Their structures were mainly elucidated by ESI-MS and NMR spectra and their physical characters. RESULTS: Six compounds were isolated from the petroleum ether section from 75% ethanol extraction of the material. Their structures were identified as taraxerol (1), epitaraxerol (2), beta-sistosterol (3), beta-sitostenone (4), jolkinolide E (5), and sesamin (6). CONCLUSION: Compounds 1, 2, 4, 5, and 6 are isolated from this plant for the first time.

[Diterpenoid alkaloids from roots of Aconitum recemulosum and their inhibitory effects on PAF-induced platelet aggregation].

OBJECTIVE: To study diterpenoid alkaloids from the roots of Aconitum recemulosum, and their inhibitory effects on PAF-induced platelet aggregation. METHOD: The root of A. recemulosum was extracted with 95% EtOH. The total alkaloids extracted were isolated and purified by several kinds of column chromatography over silica gel, RP-18, and Sephadex LH-20, and identified based on spectral analysis. And the inhibitory effects of isolated compounds on PAF-induced platelet aggregation were detected. RESULT: Five alkaloids were isolated and identified as sachaconitine (1), 14-acetylsachaconitine (2), hemsleyanine C (3), circinasine A (4), and talatisamine (5). The results showed compounds 1 and 2 have moderate inhibition effect on PAF. CONCLUSION: Compounds 1-5 were firstly isolated from this plant. Furthermore, compounds 1 and 2 possessed moderate inhibitory effects on PAF-induced platelet aggregation.