Search

Objective: To screen for α-glucosidase inhibitor active compounds in the total saponins of Baibiandou (Lablab Semen Album) based on UHPLC-Q-Exactive Orbitrap MS technology and to evaluate its hypoglycemic activity in vivo. Methods: Acarbose was used as the positive control, and the median inhibitory concentration (IC50) was used as the evaluation index of α-glucosidase inhibitory activity to establish an in vitro α-glucosidase inhibition model. Further, UHPLC-Q-Exactive Orbitrap MS technology was used to screen and identify the active compounds of α-glucosidase inhibitors in the total saponins of Baibiandou (Lablab Semen Album) in order to further verify the activity of the main active monomer and to perform homologous modeling and molecular docking of yeast-derived α-glucosidase and human-derived α-glucosidase, while the hypoglycemic activity was evaluated in diabetic mice. Results: This study successfully identified 15 compounds with potential α-glucosidase inhibitory activity, including Chikusetsusaponin IVa, from the total saponins of Baibiandou (Lablab Semen Album). Simultaneously, we verified the activity of the main active monomer Chikusetsusaponin IVa, and showed that it has strong α-glucosidase inhibitory activity. The α-glucosidase inhibitory concentration IC50 was (565.2 ± 1.026) μg/mL, and the IC50 of acarbose, which was lower than the positive control, was (706.6 ± 1.058) μg/mL. The docking energies of Chikusetsusaponin IVa were – 6.1 and – 7.7 kcal/mol with yeast-derived α-glucosidase and human-derived α-glucosidase molecules, respectively. Both showed strong binding activity, and the levels of alanine aminotransaminase (ALT), aspartate aminotransaminase (AST), UREA, Creatinine (CREA), and cholesterol (CHO) were significantly decreased by Chikusetsusaponin IVa (P < 0.05). In addition, it could repair damaged liver and pancreas cells of diabetic mice to some extent. Conclusion: This study provides a basis for screening α-glucosidase inhibitors and structural modifications of the total saponins of Baibiandou (Lablab Semen Album).

A new diketopiperazine, cyclo-(d-8-acetoxyl-Pro-l-Leu) (1), together with eight known compounds (2–9) including three enterotoxins (2–4), four diketopiperazines (5–8) and maltol (9), were isolated from the mangrove derived-soil Streptomyces sp. SCSIO 41400. The planar structures of all compounds were determined from analysis of NMR spectra, MS, optical rotation and comparing with literature data. The absolute configuration of compound 1 was assigned by electronic circular dichroism (ECD). The isolated compounds (1–9) were tested for their acetyl cholinesterase (AChE) and pancreatic lipase (PL) enzyme inhibitory activities. Among them, the new diketopiperazine (1) displayed preferable PL enzyme inhibitory activity with IC50 value of 27.3 μg/mL, while compounds 2, 5 and 6 showed weak PL enzyme inhibitory activity. Further molecular docking simulation exhibited that compound 1 could be well bind with the catalytic pocket of the PL. Besides, compound 9 showed moderate antibacterial activity against Methicillin-resistant Staphylococcus aureus with MIC value of 12.5 μg/mL, which was comparable to that of the positive control ampicillin with MIC value of 3.125 μg/mL.

The igneous complex that hosts the Yanbei porphyry tin deposit is situated along the eastern margin of the southeast China Caledonian fold belt. It intrudes a Late Jurassic granitic batholith and was unconformably covered by Late Cretaceous red beds. The complex consists mainly of volcanic (ignimbrites and minor rhyolitic lavas, tuffs, and subvolcanic rhyolite porphyry) and intrusive rocks (topaz-bearing granite porphyry and granite). These rocks are generally peraluminous with F- and VI Al-rich biotite as the main mafic mineral, and F-rich and OH-poor topaz as an accessory mineral in the granite porphyry and granite, and as an essential mineral in the topazite. Topaz in the granites is usually interstitial and crystallized during the late magmatic stage. The volcanic rocks and granites are rich in Si, K, F (SiO 2 > 75 wt %, Na 2 O/K 2 O = 0.03-0.72, F = 0.06-6.48 wt %) and incompatible trace elements (Rb, Zr, Nb, W, Sn ) and poor in Mg, Ti, Ca, P and compatible trace elements (Sr, Eu ). The chondrite-normalized rare earth element (REE) patterns for the granites generally have a distinct V shape, with strong Eu depletion (Eu/Eu (super [whitesunwithrays]) = 0.04-0.20). The main rocks of the complex have low epsilon Nd (T) values (-9.3 to -8.9 for volcanic rocks, -4.0 to -4.8 for granites), and high delta 18 O values of quartz from dacite (9.5ppm) and granites (9.6-10.1ppm). The difference in epsilon Nd (T) between the volcanic rocks and granites indicates that they are not comagmatic. The source of the volcanic rocks probably contains a greater metasedimentary component than that of the granites.The Yanbei porphyry tin deposit is located along the contact zone between topaz-bearing granite porphyry and rhyolite porphyry, and consists principally of one orebody which makes up 99 percent of the total reserves. Of the metallic minerals (5% by volume), cassiterite, pyrite, and chalcopyrite are dominant, sphalerite, wolframite, and galena are less important, and siderite, molybdenite, and stannite are minor. Cassiterite accounts for 96 percent of the total Sn reserves and stannite is the subordinate Sn-bearing mineral that occurs as rims around chalcopyrite. Cassiterite occurs mostly in disseminated form and as veinlets. The wall-rock alteration is intense and can be roughly grouped into three zones spatially arranged around the granite porphyry, namely: topaz-quartz, chloritic, and sericitic zones. Most of the orebody occurs in the topaz-quartz and chloritic zones. Hydrothermal alteration caused a decrease in K and Na and an increase in Al, Fe, Ca, Sn, W, and Cu. The delta 18 O values of quartz and cassiterite from the mineralized zones vary from 6.0 to 11 per mil, and the calculated delta 18 O (sub H 2 O) values of the ore-forming fluid range from 4.2 to 7.8 per mil. The altered rocks have elevated delta 18 O (sub H 2 O) values (14.5-9.7ppm) relative to fresh rocks. The pyrite from the ore has a limited range of delta 34 S values (-0.3-+1.5ppm). These data suggest a magmatic source for the ore-forming hydrothermal fluid.

The F-rich granites in South China could be distinguished as the high-P subtype and the low-P subtype according to their P2O5 contents. There are obvious differences in chemical composition of these two subtypes. The high-P subtype is strongly peraluminous and characterized by low silica and very low REE contents, while the low-P subtype is weakly peraluminous and characterized by high silica and very high REE contents. There are also some differences in chemical compositions of feldspars and micas for these two subtypes. The phosphorus of the high-P subtype mainly appears to be in the feldspar structure as PAISi−2 substitution or subordinately in amblygonite as an accessory mineral, while the phosphorus of the low-P subtype is mainly in apatite and other phosphate minerals.